KR102084427B1 - Wireless power receiver for controlling wireless power by using switch - Google Patents

Abstract

A wireless power receiver is disclosed that receives wireless power from a wireless power transmitter. The wireless power receiver according to the present invention includes a power receiver for receiving the wireless power from the wireless power transmitter, a rectifier for rectifying the wireless power of the AC form output from the wireless power receiver in a direct current form, and outputting the rectified power; The rectified power is input and outputs a first power having a first voltage having a lower value than the rectified power during a first period, and does not output power during a second period, thereby providing power having a predetermined voltage value. It may include a power adjusting unit for outputting.

Description

WIRELESS POWER RECEIVER FOR CONTROLLING WIRELESS POWER BY USING SWITCH}

The present invention relates to a wireless power receiver, and more particularly, to a wireless power receiver for receiving power wirelessly based on an electromagnetic resonance scheme.

Mobile terminals such as mobile phones or PDAs (Personal Digital Assistants) are driven by rechargeable batteries due to their characteristics, and in order to charge such batteries, electric energy is supplied to the batteries of the mobile terminals using a separate charging device. Typically, the charging device and the battery are configured with separate contact terminals on the outside, thereby contacting each other, thereby electrically connecting the charging device and the battery.

However, in this type of contact charging method, since the contact terminal protrudes to the outside, contamination by foreign matter is easy, and for this reason, there is a problem in that battery charging is not performed correctly. In addition, charging is not performed correctly even when the contact terminals are exposed to moisture.

In order to solve this problem, wireless charging or contactless charging technology has recently been developed and used in many electronic devices.

The wireless charging technology uses a wireless power transmission and reception, for example, a system in which the battery can be automatically charged by simply placing a mobile phone on a charging pad without connecting a separate charging connector. Generally known to the public as a cordless electric toothbrush or a cordless electric shaver. This wireless charging technology can increase the waterproof function by charging the electronics wirelessly, and there is an advantage that can increase the portability of electronic devices because no wired charger is required, and related technologies are expected to develop significantly in the coming electric vehicle era. .

Such wireless charging technologies include an electromagnetic induction method using a coil, a resonance method using resonance, and a radio wave radiation (RF / Micro Wave Radiation) method that converts electrical energy into microwaves and transmits them.

Until now, electromagnetic induction has been the mainstream, but recently, at home and abroad, it has been successful in experimenting to transmit power wirelessly at a distance of several tens of meters using microwaves. In the near future, it will wirelessly charge all electronic products without wires anytime and anywhere. The world seems to open.

A method of transmitting power by electromagnetic induction is a method of transmitting power between a primary coil and a secondary coil. When the magnet moves to the coil, an induction current is generated. The magnetic field is generated at the transmitting end and current is induced by the change of the magnetic field at the receiving end to generate energy. This phenomenon is called a magnetic induction phenomenon and the power transmission method using the same has excellent energy transmission efficiency.

In 2005, MIT's Soljacic professor, Coupled Mode Theory, announced a system that uses the resonant power transfer principle to transfer electricity wirelessly, even a few meters away from the charger. The MIT team's wireless charging system uses the concept of physics that sounds like a resonance when the tuning fork sounds. Instead of resonating the sound, the team resonated electromagnetic waves containing electrical energy. Resonant electrical energy is transmitted directly only when there is a device with a resonant frequency, and the unused part is reabsorbed into the electromagnetic field instead of spreading into the air, so unlike other electromagnetic waves, it will not affect the surrounding machinery or the body. .

Meanwhile, the conventional wireless power receiver includes a rectifying circuit for converting a received AC waveform into a DC waveform and a DC-DC converting circuit for adjusting the rectified DC waveform power to a predetermined voltage value at an output terminal. However, since the DC-DC converting circuit must use a passive element having a large external value, it is difficult to implement the circuit to have a small mounting area with high output and high efficiency. In particular, when the wireless power receiver is implemented as a mobile communication device such as a mobile phone, the increased mounting area adversely affects the thinning of the entire device.

In addition, DC-DC converting circuits can only operate below a few MHz, in that they are externally packaged active devices.

The present invention has been made to solve the above-described problem, the present invention provides a wireless power receiver that is adjusted in size by controlling the wireless power received using a switch.

In order to achieve the above, a wireless power receiver for receiving wireless power from a wireless power transmitter according to an embodiment of the present invention, the power receiving unit for receiving the wireless power from the wireless power transmitter; A rectifying unit rectifying the wireless power of the AC form output from the wireless power receiving unit in the form of DC, and outputting the rectified power; And receiving the rectified power and outputting a first power having a first voltage having a lower value than the rectified power during a first period, and outputting no power during a second period, thereby having a preset voltage value. It may include a power adjustment unit for outputting.

According to various embodiments of the present disclosure, there may be provided a wireless power receiver in which the magnitude of wireless power received by a short circuit and a disconnection of a switch is adjusted.

Accordingly, it is possible to reduce the size and weight of the conventional DC-DC converting circuit, and to significantly reduce the number of passive elements and integrated circuits. In addition, the switch includes a resonant inductor and a capacitor to obtain a stable DC output power.

In addition, it is possible to provide more precise and stable DC power by controlling the switch by comparing the synchronization signal of the wireless power received from the output power and the power receiver.

1 is a conceptual diagram illustrating an overall operation of a wireless charging system.
2 is a block diagram of a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.
3 is a block diagram of a wireless power receiver according to a comparative example with the present invention.
4 is a block diagram of a wireless power receiver according to an embodiment of the present invention.
5A through 5C are circuit diagrams of a wireless power receiver according to various embodiments of the present disclosure.
6A and 6B are graphs showing output stage voltages in a continuous current mode and a discontinuous current mode.
7A and 7B are graphs showing output stage currents in a continuous current mode and a discontinuous current mode.
8A is a block diagram of a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.
8B is a circuit diagram of a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.
9 is a circuit diagram of a wireless power receiver according to an embodiment of the present invention.
10 is a circuit diagram illustrating a method of generating a switch on / off control signal according to an embodiment of the present invention.
11 is a graph for explaining generation of a control signal according to an embodiment of the present invention.
12 is a circuit diagram of a boost bias generator according to an embodiment of the present invention.
13 is a graph for explaining a voltage applied to the boost bias generator.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in more detail. It should be noted that the same elements in the figures are represented by the same numerals wherever possible. In the following description and the annexed drawings, detailed descriptions of well-known functions and configurations that may unnecessarily obscure the subject matter of the present invention will be omitted.

1 is a conceptual diagram illustrating an overall operation of a wireless charging system. As shown in FIG. 1, the wireless charging system includes a wireless power transmitter 100 and at least one wireless power receiver 110-1, 110-2, 110-n.

The wireless power transmitter 100 may wirelessly transmit power 1-1, 1-2, 1-n to at least one wireless power receiver 110-1, 110-2, 110-n. More specifically, the wireless power transmitter 100 may wirelessly transmit power 1-1, 1-2, 1-n to only an authenticated wireless power receiver that has performed a predetermined authentication procedure.

The wireless power transmitter 100 may form an electrical connection with the wireless power receivers 110-1, 110-2, and 110-n. For example, the wireless power transmitter 100 may transmit wireless power in the form of electromagnetic waves to the wireless power receivers 110-1, 110-2, and 110-n.

Meanwhile, the wireless power transmitter 100 may perform bidirectional communication with the wireless power receivers 110-1, 110-2, and 110-n. Herein, the wireless power transmitter 100 and the wireless power receivers 110-1, 110-2, and 110-n may process or transmit and receive packets 2-1, 2-2, and 2-n composed of predetermined frames. The above-described frame will be described later in more detail. In particular, the wireless power receiver may be implemented as a mobile communication terminal, a PDA, a PMP, a smart phone, or the like.

The wireless power transmitter 100 may wirelessly provide power to the plurality of wireless power receivers 110-1, 110-2, and 110-n. For example, the wireless power transmitter 100 may transmit power to the plurality of wireless power receivers 110-1, 110-2, and 110-n through a resonance method. When the wireless power transmitter 100 adopts a resonance method, a distance between the wireless power transmitter 100 and the plurality of wireless power receivers 110-1, 110-2, and 1110-n may be 30 m or less. In addition, when the wireless power transmitter 100 adopts an electromagnetic induction method, a distance between the power supply device 100 and the plurality of wireless power receivers 110-1, 110-2, and 110-n may be preferably 10 cm or less.

The wireless power receivers 110-1, 110-2, and 110-n may receive wireless power from the wireless power transmitter 100 to charge the battery included therein. In addition, the wireless power receivers 110-1, 110-2, and 110-n transmit signals for requesting wireless power transmission, information necessary for wireless power reception, wireless power receiver status information, or wireless power transmitter 100 control information. 100). Information on the above-described transmission signal will be described later in more detail.

Also, the wireless power receivers 110-1, 110-2, and 110-n may transmit messages indicating respective states of charge to the wireless power transmitter 100.

The wireless power transmitter 100 may include display means such as a display, and the wireless power receivers 110-1, 110-2, and 110-n based on messages received from the wireless power receivers 110-1, 110-2 and 110-n, respectively. Each state can be displayed. In addition, the wireless power transmitter 100 may also display the estimated time until each of the wireless power receivers 110-1, 110-2, and 110-n is fully charged.

The wireless power transmitter 100 may transmit a control signal for disabling the wireless charging function to each of the wireless power receivers 110-1, 110-2, and 110-n. The wireless power receiver that receives the disable control signal of the wireless charging function from the wireless power transmitter 100 may disable the wireless charging function.

2 is a block diagram of a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.

As shown in FIG. 2, the wireless power transmitter 200 may include a power transmitter 211, a controller 212, and a communicator 213. In addition, the wireless power receiver 250 may include a power receiver 251, a controller 252, and a communication unit 253.

The power transmitter 211 may provide power required by the wireless power transmitter 200, and may wirelessly provide power to the wireless power receiver 250. Here, the power transmitter 211 may supply power in the form of an AC waveform, and may also supply power in the form of an AC waveform by converting it into an AC waveform using an inverter while supplying power in the form of a DC waveform. The power transmitter 211 may be implemented in the form of a built-in battery, or may be implemented in the form of a power receiving interface to receive power from the outside and supply it to other components. It will be readily understood by those skilled in the art that the power transmitter 211 is not limited as long as it can provide power of a constant AC waveform.

In addition, the power transmitter 211 may provide the AC waveform to the wireless power receiver 250 in the form of electromagnetic waves. The power transmitter 211 may further include a loop coil, and thus may transmit or receive a predetermined electromagnetic wave. When the power transmitter 211 is implemented as a loop coil, the inductance L of the loop coil may be changeable. On the other hand, the power transmitter 211 will be readily understood by those skilled in the art that there is no limitation as long as it is a means for transmitting and receiving electromagnetic waves.

The controller 212 may control overall operations of the wireless power transmitter 200. The controller 212 may control the overall operation of the wireless power transmitter 200 using an algorithm, a program, or an application required for control read from a storage unit (not shown). The controller 212 may be implemented in the form of a CPU, a microprocessor, or a minicomputer. The detailed operation of the controller 212 will be described later in more detail.

The communication unit 213 may communicate with the wireless power receiver 250 in a predetermined manner. The communication unit 213 communicates with the communication unit 253 of the wireless power receiver 250 using near field communication (NFC), Zigbee communication, infrared communication, visible light communication, Bluetooth method, Bluetooth low energy method, and the like. Can be performed. The communication unit 213 according to an embodiment of the present invention may perform communication using a Bluetooth low energy method. In addition, the communication unit 213 may use a CSMA / CA algorithm. The configuration related to frequency and channel selection used by the communication unit 213 will be described later in more detail. On the other hand, the above-described communication method is merely exemplary, the scope of the present invention is not limited by the specific communication method performed by the communication unit 213.

Meanwhile, the communication unit 213 may transmit a signal for information of the wireless power transmitter 200. Herein, the communication unit 213 may unicast, multicast, or broadcast the signal.

The communication unit 213 may receive power information from the wireless power receiver 250. Herein, the power information may include at least one of the capacity of the wireless power receiver 250, the battery remaining amount, the number of charges, the usage amount, the battery capacity, and the battery ratio. In addition, the communication unit 213 may transmit a charging function control signal for controlling the charging function of the wireless power receiver 250. The charging function control signal may be a control signal for controlling the wireless power receiver 251 of the specific wireless power receiver 250 to enable or disable the charging function.

The communication unit 213 may receive a signal from not only the wireless power receiver 250 but also another wireless power transmitter (not shown). For example, the communication unit 213 may receive a notice signal of the above-described frame of Table 1 from another wireless power transmitter.

Meanwhile, in FIG. 2, although the power transmitter 211 and the communication unit 213 are configured with different hardware so that the wireless power transmitter 200 is communicated in an out-band format, this is exemplary. According to the present invention, the power transmitter 211 and the communication unit 213 may be implemented in one piece of hardware so that the wireless power transmitter 200 may perform communication in an in-band format.

The wireless power transmitter 200 and the wireless power receiver 250 may transmit and receive various signals. Accordingly, the wireless power transmitter 250 subscribes to the wireless power network managed by the wireless power transmitter 200 and wireless power transmission and reception. The charging process through may be performed, and the above-described process will be described in more detail below.

3 is a block diagram of a wireless power receiver according to a comparative example with the present invention.

As shown in FIG. 3, the wireless power receiver 250 includes a power receiver 251, a controller 252, a communication unit 253, a rectifier 254, a DC / DC converter 255, a switch unit 256. And a charging unit 257.

The description of the power receiver 251, the controller 252 and the communication unit 253 will be omitted here. The rectifier 254 may rectify the wireless power received by the power receiver 251 in the form of direct current, for example, may be implemented in the form of a bridge diode. The DC / DC converter 255 may convert the rectified power into a predetermined gain. For example, the DC / DC converter 255 may convert the rectified power such that the voltage of the output terminal 259 is 5V.

The switch unit 256 may connect the DC / DC converter 255 and the charging unit 257. The switch unit 256 may maintain an on / off state under the control of the controller 252. The charging unit 257 may store the converted power input from the DC / DC converter 255 when the switch unit 256 is in an on state.

However, the wireless power receiver according to the comparative example for comparison with the present invention includes a DC / DC converter 255, and thus, the number of passive elements and integrated circuits increases, and it is difficult to miniaturize.

4 is a block diagram of a wireless power receiver according to an embodiment of the present invention.

As shown in FIG. 4, the wireless power receiver 400 may include a power receiver 410, a rectifier 420, a power adjuster 430, and a load unit 440.

The power receiver 410 may receive power from a wireless power transmitter (not shown). The rectifier 420 may rectify and output the AC-type power received by the power receiver 410 in a DC form. The power adjusting unit 430 may convert the regulated power to have a predetermined value, for example, a voltage of 5V, and regulate and output the regulated power. The load unit 440 may store power.

In particular, the power adjusting unit 430 may output a first power having a first voltage value during a first period, and output a second power having a second voltage during a second period. Accordingly, the power adjusting unit 430 may output power having a predetermined value, for example, a voltage of 5V. In particular, the power adjuster 430 does not include a converting means including a passive element, and may simply convert the voltage value of power based on the on / off adjustment of the switch. Accordingly, it is possible to reduce the size and weight of the conventional DC-DC converting circuit, and to significantly reduce the number of passive elements and integrated circuits. In addition, the switch includes a resonant inductor and a capacitor to obtain a stable DC output power. In addition, it is possible to provide more precise and stable DC power by controlling the switch.

5A is a circuit diagram of a wireless power receiver according to an embodiment of the present invention. In particular, the embodiment of FIG. 5A is a circuit diagram of the wireless power receiver in the first period described above in FIG. 4.

As shown in FIG. 5A, the wireless power receiver includes a resonant circuit 510, a rectifier circuit 520, and a first switch 532, a second switch 533, a third switch 534, and a first capacitor 536. ) And a second capacitor 537.

The resonant circuit 510 may include a capacitor 511 and a coil 512, and may receive power having a value of I _RS from a wireless power transmitter based on a resonance method.

The rectifier 520 may include at least one diode and may rectify and output the AC power input from the resonant circuit 510 in a DC shape. The rectifier 520 may output rectified power having a current value of I _RT and a voltage value of V _XH .

The rectifier 520 may be connected to the first node 531. A voltage value of V _XH may be applied to the first node 531. The first node 531 may be connected to the first switch 532 and the second capacitor 537. The second capacitor 537 may have a capacitance of C _FL . Herein, the first capacitor 536 and the second capacitor 537 may be variable capacitors, and the capacitances C _out and C _FL may be changed. As the capacitances of the first capacitor 536 and the second capacitor 537 are adjusted, the output voltage in the second period (OFF duty) can be adjusted. The above-mentioned capacitances C _out and C _FL are voltage divisions and may be referred to as capacitive voltage dividers. In addition, according to the transmission power, the effect of using the capacitor value required for regulation in the first period (ON duty) is created. The first period (ON duty) and the second period (OFF duty) will be described later in more detail.

Meanwhile, the first switch 532, the second switch 533, and the third switch 534 may be implemented as a high-side PMOS switch or a low-side NMOS switch, respectively. Accordingly, integration with the first switch 532, the second switch 533, the third switch 534, and the rectifier circuit may be possible.

One end of the first switch 532 may be connected to the first node 531, and the other end thereof may be connected to one end of the first capacitor 536. Meanwhile, during the first period, the first switch 532 may be controlled to be in an on state, and thus the rectifier 520 may be connected to one end of the first capacitor 536. The other end of the second capacitor 537 may be connected to the second node 535, and one end of the second switch 533 and one end of the third switch 534 may be connected to the second node 535. . The other end of the second switch 533 may be connected to the other end of the first switch 532 and one end of the first capacitor 536. In particular, during the first period, the second switch 533 can be controlled to the off state. Meanwhile, the second node 535 may be connected to one end of the third switch 534, and the other end of the third switch 534 may be connected to the other end of the first capacitor 536 and the ground. In particular, during the first period, the third switch 534 can be controlled to an on state, whereby the other end of the second capacitor 537 can be grounded. That is, during the first period, the first switch 532 and the third switch 534 may be controlled to the on state, and the second switch 533 may be controlled to the off state. Accordingly, the voltage value of V _XH applied to the first node 531 may be distributed and applied to the first capacitor 536 and the second capacitor 537. This is due to the first capacitor 536 and the second capacitor 537 being connected in parallel. Accordingly, the voltage value of the first capacitor 536, which is an output terminal, has a value smaller than V _XH as shown in FIG. 6A. 6A is a graph of voltage values applied to the output stage during the first period. As shown in FIG. 6A, it can be seen that the output terminal voltage Vout is lower than V _XH during the first period (ON duty).

5B is a circuit diagram of a wireless power receiver according to an embodiment of the present invention. In particular, the embodiment of FIG. 5B is a circuit diagram of the wireless power receiver in the second period described above in FIG. 4. FIG. 5B shows only the right end of the rectifying part 520 of FIG. 5A. During the second period, as shown in FIG. 5B, the first switch 532 and the third switch 534 may be controlled to be in an off state, and the second switch 533 may be controlled to be in an on state. Accordingly, the first node 531 is connected to the second capacitor 537, and the second capacitor 537 is connected to the first capacitor 536. As a result, V _XH applied to the first node 531 may be applied to the first capacitor 536 as it is. Accordingly, the voltage value of the first capacitor 536 as the output terminal has a V _XH value as shown in FIG. 6A. This is due to the first capacitor 536 and the second capacitor 537 connected in series. 6A is a graph of the voltage value applied to the output stage during the second period. As shown in FIG. 6A, it may be confirmed that the output terminal voltage Vout is V _XH during the second period (OFF duty). As described above, the output voltage value is less than V _XH during the first period, and the output voltage value of V _XH is output during the second period, thereby outputting a predetermined voltage value, for example, 5 V, for the total period.

Meanwhile, the output voltage modes of the first period and the second period may be referred to as continuous current mode (CCM). In FIG. 7A, a graph showing the current in the CCM. As shown in FIG. 7A, I _RS and I _RT may increase during a first period (ON duty), and I _RS and I _RT may decrease during a second period (OFF duty). However, the currents during the first period and the second period may be continuous. The increase in current during the first duty period (ON duty) may be due to the drop in the equivalent impedance from the position of the wireless power transmitter to increase the transmission power. On the other hand, the decrease in current during the second period (OFF duty) may be due to the increase in the equivalent impedance from the standpoint of the wireless power transmitter and the decrease in the transmission power. CCM may be used, for example, when the transmit power is large, and DCM may be used, for example, when the transmit power is small.

5C is a circuit diagram of a second period in the case of a discontinuous current mode (DCM). Meanwhile, it may be the same as FIG. 5A during the first period of DCM. During the second period, as shown in FIG. 5C, the first switch 531, the second switch 532, and the third switch 534 may all be controlled to the off state. Accordingly, the voltage applied to the first capacitor 536, which is an output terminal, may have a value attenuated from V _XH as shown in FIG. 6B. That is, a voltage value lower than V _XH is output during the first period, and a voltage value attenuating from V _XH is output during the second period, and accordingly, a predetermined voltage, for example, a voltage value of 5 V, is output during the total period. Can be.

7B is a graph showing the current value in DCM. As shown in FIG. 7B, I _RS and I _RT in the second period may have a value of zero. This may be due to the floating of V _XH .

As described above, in the CCM mode or the DCM mode, a predetermined voltage, for example, a voltage value of 5 V may be maintained and output stably even without a passive element.

8A is a block diagram of a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.

As illustrated in FIG. 8A, the wireless power transmitter 800 may include a power transmitter 811, a controller 812, a communication unit 813, and a power supply unit 814. In addition, the wireless power receiver 850 may include a power receiver 851, a communication unit 853, a rectifier 860, a power adjuster 870, and a load unit 880. The power adjuster 870 may include a switch 871 and a controller 872.

The power supply unit 814 may supply power to the power transmitter 811, and the amount of power supplied may be controlled by the controller 812. The power transmitter 811 may transmit wireless power to the power receiver 851 based on a resonance method.

The rectifier 860 may rectify the input power and output the rectified power to the power adjuster 870. In particular, the rectifier 860 may output the rectified power to the switch unit 870. The switch unit 870 may include at least one switch, and output the first power having the first voltage value or the second power having the second voltage value based on the on / off state of the at least one switch. Can be. Meanwhile, power having a predetermined voltage value, for example, a voltage value of 5V may be output from the power adjuster 870 by outputting the first power and the second power.

The controller 872 may receive some power from the rectifier 860. The controller 872 may control an on / off state of each of the at least one switch included in the switch unit 870 based on some power received from the rectifier 860. For example, the controller 872 may control an on / off state of each of the at least one switch included in the switch unit 870 such that the first power having the first voltage value is output during the first period. During the two periods, the on / off state of each of the at least one switch included in the switch unit 870 may be controlled to output the second power having the second voltage value. Accordingly, the controller 872 controls the on / off state of each of the at least one switch included in the switch unit 870 to output power having a predetermined voltage value, for example, a voltage value of 5V, for the total period. Can be.

Meanwhile, when excessive power is applied to the rectifier 860, the controller 872 may control the communication unit 853 to transmit a signal for adjusting the power output from the power supply unit 814 to the communication unit 813. have.

The load unit 880 may receive a power having a preset voltage value output from the switch unit 870, for example, a voltage value of 5V.

8B is a circuit diagram of a wireless power transmitter and a wireless power receiver according to an embodiment of the present invention.

In FIG. 8B, the power supply 814 may include a power supply means, a Class-E Amp, and an inverter. The power supply means can vary within the range of 10V to 14V. The power transmitter 811 may include a resonance circuit. Here, the resonant frequency may be 6.78Mhz, for example.

The power receiver 851 may receive, for example, wireless power at a resonance frequency of 6.78 Mhz, and may include a resonance circuit. Meanwhile, the rectifier may include first to fourth diodes 861 to 614 and a third capacitor 865 having a capacitance of C _LM . Meanwhile, signals at both ends of the third capacitor 865 may be input to the timing controller 884. The timing controller 884 may generate and output a clock CLK signal capable of controlling the on / off states of the first to third switches 874, 877, 878. The timing controller 884 may generate a clock signal based on the delay signal 881, the mode selection signal 882, and the duty signal 883. The gate driving signal generating element 885 may generate and output a gate driving signal based on a clock signal. In addition, the gate driving signal generating element 885 may generate a gate driving signal using the output results of the comparator 888 and the calculator 887. This will be described later in more detail.

Meanwhile, the on / off state of the first to third switches 874, 877, 878 may be controlled based on the clock signal. Based on the on / off states of the first to third switches 874, 877, 878, for example, a first voltage is applied to the output terminal 879 during the first period, and a second voltage is applied to the output terminal 879 during the second period. Value can be applied.

9 is a circuit diagram of a wireless power receiver according to an embodiment of the present invention. In FIG. 9, only additional components will be described in comparison with FIG. 5A. In FIG. 9, a first resistor 901, a second resistor 902, a comparator 903, a switch controller 904, and a signal detector 905 may be included.

One end of the first resistor 901 may be connected to an output terminal, and the other end thereof may be connected to one end of the second resistor 902 and the first input unit (−) of the comparator 903. The other end of the second resistor 902 may be grounded. The reference voltage Vref may be applied to the second input unit + of the comparator 903. The comparator 903 may compare the reference voltage Vref with the voltage applied to the first input unit (−), and output the comparison result to the switch controller 904. The switch controller 904 may control an on / off state of each of the first switch 532, the second switch 533, and the third switch 534 based on the comparison result. Meanwhile, the signal detector 905 may receive the AC synchronization signal from the resonance circuit 510 and output the feedback signal to the switch controller 904. The switch controller 904 may control an on / off state of each of the first switch 532, the second switch 533, and the third switch 534 based on the AC synchronization signal.

For example, the reference voltage Vref of the comparator 903 may be set to 5V. For example, when a voltage higher than 5 V, which is a reference voltage, is applied to the output terminal, the power adjusting unit may control the on / off state of the switch to maintain the voltage applied to the output terminal at 5 V. FIG. As described with reference to FIGS. 5A and 5B, during the first period in which the first switch 532 and the third switch 534 are controlled to the on state and the second switch 533 is controlled to the off state, Low voltage is applied. In addition, a relatively high voltage is applied during the second period in which the first switch 532 and the third switch 534 are controlled to the off state and the second switch 533 is controlled to the on state. The power regulator may adjust the first period to be relatively longer than before, so that the voltage at the output terminal is applied at 5V. On the contrary, when a voltage lower than 5 V, which is a reference voltage, is applied to the output terminal, the power adjuster sets the first period to be relatively shorter than before to maintain the voltage applied to the output terminal at 5 V so that the output terminal voltage is applied at 5 V. I can adjust it.

On the other hand, in the case of DCM, the power is output during the first period and the power is not output during the second period. Accordingly, when a voltage higher than the reference voltage of 5V is applied to the output terminal, the power adjuster sets the first period to be relatively shorter than before to maintain the voltage applied to the output terminal at 5V, and the output terminal voltage is applied at 5V. Can be adjusted as possible. In addition, when a voltage lower than 5 V, which is a reference voltage, is applied to the output terminal, the power adjusting unit sets the first period relatively longer than before to maintain the voltage applied to the output terminal at 5 V so that the voltage at the output terminal is applied at 5 V. I can adjust it.

10 is a circuit diagram illustrating a method of generating a switch on / off control signal according to an embodiment of the present invention. The circuit diagram operation of FIG. 10 will be described with reference to the graph of FIG. 11. 11 is a graph for explaining generation of a control signal according to an embodiment of the present invention.

The rectifier circuit may include first to fourth diodes 1061 to 1064 and a capacitor 1065 having a capacitance of C _LM . A node 1066 exists between the first diode 1061 and the third diode 1063, and a node 1067 exists between the second diode 1062 and the fourth diode 1064. V _{IN +} may be applied to the node 1066, and V _{IN −} may be applied to the node 1067. For example, differential signals of V _{IN +} and V _{IN −} in FIG. 11 may be applied to the nodes 1066 and 1067, respectively.

The node 1066 may be connected to one end of the resistor 1011, and the other end of the resistor 1011 may be connected to one end of the resistor 1012. The other end of resistor 1012 may be grounded. The other end of the resistor 1011 and one end of the resistor 1012 may be input to the first input unit (+) of the calculator 1013. Meanwhile, one end of the resistor 1019 and one end of the resistor 1014 may be connected to the second input unit (−) of the calculator 1013. The other end of the resistor 1019 may be connected to the node 1067, and the other end of the resistor 1014 may be connected to one end of the capacitor 1015. The other end of the capacitor 1015 may be grounded.

Accordingly, differential signals of V _{IN +} and V _{IN −} may be input to each of the first input unit (+) and the second input unit (−) of the calculator 1013. The calculator 1013 may calculate a differential signal to be input and output a compound sync signal 1016. In FIG. 11, the synthesized synchronization signal Comp Sync may be generated by calculating a differential signal of V _{IN +} and V _{IN −} .

Meanwhile, the node 1067 may be connected to the inverter 1017. The inverter 1017 may invert the V _{IN −} signal applied to the node 1067 and output an inverting synchronization signal (Inv Sync) 1018. The inverting sync signal Inv Sync in FIG. 11 may be generated by inverting the V _{IN −} signal. The selection signal SEL may be applied to the switch 1019 to determine whether the switch 1019 receives a composite sync signal or an inverting sync signal. For example, the select signal SEL controls the switch 1019 to receive an inverted synchronization signal Inv Sync during the first period (ON duty), and the composite synchronization signal (Comp) during the second period (OFF duty). The switch 1019 may be controlled to receive Sync.

The delay unit 1020 may output the clock signal CLK by delaying the inverted synchronization signal Inv Sync or the composite synchronization signal Comp Sync. As illustrated in FIG. 11, a clock signal CLK in which an inverted synchronization signal Inv Sync is delayed is generated during a first period (ON duty), and a synthesized synchronization signal (Comp Sync) during a second period (OFF duty). The delayed clock signal CLK is generated.

12 is a circuit diagram of a boost bias generator according to an embodiment of the present invention. The boost bias generator according to FIG. 12 may be connected to the node 531 and the output terminal V _out of FIG. 9, for example.

The node 1201 may be connected to an EEF 1210 and a schottky diode 1202. The EEF 1210 may include a capacitor 1211, a resistor 1212, and a resistor 1213. Capacitor 1211 may have a capacitance of, for example, 50 fF, resistor 1212 may have a resistance of, for example, 700 Ω, and resistor 1213 may have a resistance of, for example, 10 kΩ. . The EEF 1210 may be connected to the third sub switch 1221. The third sub switch 1221 may be implemented as an FET, and the EEF 1210 may be connected to the gate terminal of the third sub switch 1221. Meanwhile, the drain of the third sub switch 1221 may be connected to the gate of the first sub switch 1223. The source of the third sub switch 1221 may be connected to the source of the diode 1227 and the second sub switch 1224. The drain and gate of the second sub-switch 1224 may be connected to the source and the node 1225 of the first sub-switch 1223. A capacitor 1226 may be disposed between the node 1226 and the output terminal V _out . The Schottky diode 1202 may be connected to the drain of the first sub switch. On the other hand, there may be a plurality of diodes 1227, for example, five.

For example, when the switches 532, 533, and 534 in FIG. 9 are implemented as N type MOSFETs, the boost bias generator may be operated by maintaining a predetermined voltage higher than the voltage V _{out of the} output terminal. In particular, the boost bias can generate a voltage capable of substantially driving the first switch 532 in FIG. 9. In particular, when a high voltage is applied to V _XH while the first switch 532 is switched between V _out and 2V _out in the CCM mode, the boost bias may provide a high voltage.

In addition, the boost bias generator may maintain the voltage applied to the voltage V _B applied to the node 1225 to be a predetermined voltage, for example, 10V or less. For example, as illustrated in FIG. 13, the voltage applied to the voltage V _B applied to the node 1225 may be maintained below 10 V, which is a predetermined voltage. Accordingly, the boost bias generator may control the switches 532, 533, and 534 to operate when the N type MOSFET is implemented, while controlling the overvoltage to not be applied to the wireless power receiver.

For example, when the difference between the voltage of V _G1 and the threshold voltage V _th of the first sub switch 1223 is less than V _B , the first sub switch 1223 may be turned on. In addition, the difference between the voltage of V _G1 and the threshold voltage V _th of the first sub-switch 1223 is V _B. In this case, the first sub-switch 1223 may be turned off. The boost bias generator may be operated based on the above operation.

Although the preferred embodiments of the present invention have been illustrated and described above, anyone of ordinary skill in the art to which the present invention pertains preferably implements the present invention without departing from the spirit and scope of the present invention. Of course, the examples can be changed in various ways. Therefore, various modifications may be made without departing from the spirit of the invention as claimed in the claims, and such modifications should not be individually understood from the technical spirit or outlook of the invention.

Claims (22)

A wireless power receiver for receiving wireless power from a wireless power transmitter,
A power receiver configured to receive the wireless power from the wireless power transmitter;
Rectifier for rectifying the wireless power of the AC form output from the power receiver in the form of direct current, and outputs the rectified power; And
And a power adjuster including at least one switch and at least one capacitor and receiving the rectified power to output power having a predetermined voltage value.
The power adjustment unit,
Controlling the at least one switch to apply at least a portion of the rectified power to the at least one capacitor to output a first power having a first voltage having a lower value than the rectified power during a first period of time; And controlling at least one switch not to output power during a second period of time. The method of claim 1,
And the power adjuster increases the impedance of the wireless power receiver during the first period. The method of claim 1,
And the power adjuster controls the wireless power received by the power receiver to increase during the first period. The method of claim 1,
The power adjustment unit,
A node connected to the output terminal of the rectifier;
A first switch, one end of which is connected to the node;
A first capacitor having one end connected to the node;
A second switch having one end connected to the other end of the first capacitor;
A third switch having one end connected to the other end of the first capacitor;
And a second capacitor having one end connected to the other end of the first switch and the other end of the second switch, and the other end connected to the other end of the third switch. The method of claim 4, wherein
The power adjustment unit,
And controlling the first switch and the third switch in an on state and controlling the second switch in an off state during the first period. The method of claim 5, wherein
The power adjustment unit,
And connecting the first capacitor and the second capacitor in parallel to control to output a first power having the first voltage. The method of claim 4, wherein
The power adjustment unit,
And during the first period, control the first switch, the second switch and the third switch to an off state. The method of claim 7, wherein
The power adjustment unit,
Wireless power receiver characterized in that the control does not output the power by not connecting the first capacitor and the second capacitor. The method of claim 4, wherein
The power regulator includes a switch controller that controls the first switch, the second switch, and the third switch based on at least one of a voltage applied to an output terminal of the power regulator and a synchronization signal received by the power receiver. Wireless power receiver, characterized in that. The method of claim 9,
And a comparator comparing the voltage applied to the output terminal of the power adjusting unit with a reference voltage and outputting a comparison result to the switch controller. The method of claim 10,
The power adjusting unit, when the voltage applied to the output terminal of the power adjusting unit is greater than the reference voltage, the wireless power receiver, characterized in that for setting the time of the first period shorter than before. The method of claim 10,
The power adjusting unit, when the voltage applied to the output terminal of the power adjusting unit is less than the reference voltage, the wireless power receiver, characterized in that for setting the time of the first period longer than before. The method of claim 1,
And a first differential signal and a second differential signal are input to the rectifier. The method of claim 13,
The power adjuster may include at least one of an operator configured to calculate the first differential signal and the second differential signal to output a synthesized synchronization signal, and an inverter to invert the second differential signal to output an inverted synchronization signal. Wireless power receiver, characterized in that. The method of claim 14,
The power adjusting unit includes a delay unit for outputting a synchronization signal by delaying at least one of the synthesis synchronization signal and the inverting synchronization signal. The method of claim 15,
The power regulator further comprises a switch for switching between the calculator and the inverter and connected to the delay unit. The method of claim 16,
And the power adjusting unit controls the switch to connect the inverter and the delay unit during the first period, and controls the switch to connect the calculator and the delay unit during the second period. The method of claim 1,
And a boost bias generator coupled to an output of the rectifier and an output of the power adjuster. The method of claim 18,
The boost bias generator,
An EEF connected to the output terminal of the rectifier;
A schottky diode connected to the output of the rectifier;
A first sub switch having a drain connected to the Schottky diode and a source connected to an output terminal of the power regulator;
A second sub switch having a drain and a gate connected to a source of the first sub switch;
A third sub switch having a drain connected to a gate of the first sub switch and a source connected to a source of the second sub switch; And
And at least one diode coupled to the source of the second sub-switch and the source of the third sub-switch. The method of claim 19,
The boost bias generator further comprises a capacitor disposed between the source of the first sub-switch and the output terminal of the power adjuster. The method of claim 20,
When the difference between the threshold voltage of the first sub-switch and the gate voltage of the first sub-switch is smaller than the voltage applied to the source of the first sub-switch, the boost bias generator turns on the first sub-switch. Wireless power receiver, characterized in that for controlling. The method of claim 20,
The boost bias generator is configured to control the first sub-switch to an off state when a difference between a threshold voltage of the first sub-switch and a gate voltage of the first sub-switch is equal to or greater than a voltage applied to a source of the first sub-switch. Wireless power receiver, characterized in that.

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