JP3192960U - Backlight drive module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a backlight drive module capable of flexibly responding to specifications of an LCD system and an LCD system capable of reducing manufacturing cost with a high degree of design freedom and reducing inventory risk. A backlight drive module 22 is arranged independently of an LCD device 1. The backlight drive module 22 generates a maximum backlight current control signal that can be varied depending on the type of LCD device. [Selection diagram] Fig. 1

Description

  The present invention relates to a liquid crystal display / LCD technology, and more particularly to a backlight driving module used in an LCD device.

  Conventionally, a liquid crystal display device with an LED backlight having a built-in backlight driving module has been used (see, for example, Patent Document 1). Conventional liquid crystal display devices have high brightness using LEDs and can obtain stable light emission.

U.S. Pat. No. 8,294,660

  The conventional liquid crystal display (LCD) device has a sophisticated design feeling that does not take up space due to the thinning, but there is a problem that the degree of freedom in device design is low and the manufacturing cost increases as the thickness is reduced. . Further, the backlight driving module is incorporated in the LCD device, and if it is broken, a repair cost is required. On the other hand, if we try to meet the demands of users, the specifications of LED backlight liquid crystal display devices such as size and model number will increase, and a variety of backlight drive modules will have to be prepared. There is also a problem that is expensive. Further, the type of the LCD device varies depending on the size and model number of the LCD panel, and it goes without saying that the LCD panel is manufactured such that the panel size differs depending on the manufacturer.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a backlight driving module that can flexibly respond to the specifications of the LCD device and can reduce inventory risk. .

  In order to achieve the above object, the present invention provides an LED backlight module for a liquid crystal display (LCD) device comprising a video processing module for generating a backlight on control signal and a light emitting diode (LED) backlight module. A backlight driving signal for driving, a decoding circuit for generating a variable maximum backlight current control signal, the maximum backlight current control signal and the backlight on control signal; Receiving the backlight on signal by generating the backlight driving signal based on the maximum backlight current control signal and the backlight on control signal, connected to the decoding circuit and the video processing module for receiving; Provided to the LED backlight module by a control signal A drive circuit that outputs a backlight current output for determining whether or not the backlight current output is maximum and a current maximum value of the backlight current output related to the maximum backlight current control signal. A light driving module is provided.

  Since the backlight driving module is arranged outside the LCD device, the backlight driving module can be arranged independently of the LCD device, so that the design flexibility of the LCD device is high. Since the backlight drive module can change the maximum value of the backlight current output according to the type of LCD device, it can be used without replacing the backlight drive module even if the type of LCD device is different. Risk can be reduced.

1 is a functional block diagram schematically showing a configuration of an LCD system according to a first embodiment of the present invention. It is a figure which shows the timing chart of a backlight on (ON) control signal in a 1st Example. It is a functional block diagram which shows the structure of the backlight drive module of a 1st Example. It is a figure which shows the timing chart of the backlight on control signal by the LCD system which concerns on 2nd Example of this invention. It is a functional block diagram which shows the structure of the backlight drive module of a 2nd Example. It is a figure which shows the timing chart of the backlight on control signal by the LCD system which concerns on 3rd Example of this invention. It is a functional block diagram which shows the structure of the backlight drive module of a 3rd Example. It is a figure which shows the timing chart of the backlight on control signal and maximum brightness control signal by the LCD system which concerns on 4th Example of this invention. It is a functional block diagram which shows the structure of the backlight drive module of a 4th Example. It is a figure which shows the timing chart of the backlight on control signal and maximum brightness control signal by the LCD system which concerns on 5th Example of this invention. It is a functional block diagram which shows the structure of the backlight drive module of a 5th Example. It is a figure which shows the timing chart of the backlight on control signal and maximum brightness control signal by the LCD system which concerns on 6th Example of this invention. It is a functional block diagram which shows the structure of the backlight drive module of a 6th Example. It is a functional block diagram which shows roughly the structure of the LCD system which concerns on the 7th Example of this invention.

  Hereinafter, some embodiments of the present invention will be described in detail with reference to the drawings.

(First embodiment)
The LCD system according to the first embodiment includes a liquid crystal display (LCD) device 1 and an AC adapter 2 as shown in FIGS. The LCD device 1 is, for example, a monitor or a TV device, and includes a video processing module 11, a light emitting diode (LED) backlight module 12, and other necessary components such as an LCD panel. The AC adapter 2 is provided independently of the LCD device 1 and includes an AC / DC conversion module 21 and a backlight driving module 22.

  The video processing module 11 generates a power saving control signal, a backlight on control signal, and a dimming signal. The backlight on control signal is switched between the first voltage V1 and the second voltage V2 according to the type of the LCD device 1.

  The AC / DC conversion module 21 is connected to the video processing module 11 and the backlight driving module 22 so that an AC line voltage is input and a power saving control signal is received from the video processing module 11. The AC / DC conversion module 21 converts the AC line voltage into a first DC voltage, a second DC voltage, or a third DC voltage, and the video processing module 11 converts the first DC voltage and the second DC voltage. And the backlight drive module 22 are supplied to supply power, and the third DC voltage is selectively output to the video processing module 11 based on the power saving control signal. In this example, the first DC voltage is 5 V, for example, the second DC voltage is 32 V, and the third DC voltage is 12 V. In order to switch whether or not to save power, for example, the logic level of the power saving control signal is switched between a high voltage and a low voltage. For example, when the power saving control signal is switched to a high voltage, the third DC voltage is output from the AC / DC conversion module 21, and when the power saving control signal is switched to a low voltage, the AC / DC conversion module 21 outputs the third DC voltage. 3 DC voltage is not output.

  The backlight driving module 22 includes a decoding circuit 221 and a driving circuit 222. The decoding circuit 221 is connected to the video processing module 11 so as to receive the backlight on control signal, compares the second voltage V2 in the backlight on control signal with at least one reference voltage, A comparison unit 2211 is provided that generates a maximum backlight current control signal associated with the type of the LCD device 1 on the basis of the result of the comparison. As described above, the maximum backlight current control signal varies depending on the second voltage V2 of the backlight on control signal, in other words, varies depending on the type of the LCD device 1. The drive circuit 222 is connected to the decoding circuit 221 and is connected to the video processing module 11 and the LED backlight module 12, receives a maximum backlight current control signal from the decoding circuit 221, and receives a backlight from the video processing module 11. An on control signal and a dimming control signal are received.

  The driving circuit 222 generates a backlight driving signal based on the maximum backlight current control signal, the backlight on control signal, and the dimming control signal, and outputs the backlight driving signal to drive the LED backlight module 12, thereby the backlight. A backlight current output for determining whether or not to be provided to the LED backlight module 12 by the ON control signal, a current maximum value (Imax) of the backlight current output related to the maximum backlight current control signal, and dimming The current average value of the backlight current output related to the control signal is output.

  In this embodiment, the second voltage V2 is 2V, 3.5V, 5V depending on the type of the LCD device, and the reference voltage includes 3V, 4V. When the backlight on control signal is the first voltage V <b> 1, the backlight current output to be given to the LED backlight module 12 is not generated, and no current flows through the LED backlight module 12.

  When the backlight control signal is the second voltage V2, a backlight current output that causes a pulsation between the maximum current value Imax and zero is output to the LED backlight module 12, and the LED backlight module 12 is driven. Note that the maximum current value Imax is determined by Equation 1 based on the result of comparing the second voltage V2 with the two reference voltages 3V and 4V. The backlight current output is a pulse width modulated to have a duty ratio associated with the dimming control signal.

  Note that the control logic of the decoding circuit 221 and the driving circuit 222 may be combined into one integrated circuit, or may be combined into several integrated circuits. For example, the control logic of the decoding circuit and the driving circuit 222 may be assembled into one integrated circuit, or when the control logic of the driving circuit 222 is assembled into another integrated circuit, the decoding circuit 221 is integrated into another integrated circuit. It may be assembled. As another example, the backlight drive module 22 may be provided in the LCD device 1 instead of the AC adapter 2.

  Advantages of the LCD system configured as described above will be described below.

  Since the backlight drive module 22 is disposed outside the LCD device 1, the backlight drive module 1 can be disposed independently of the LCD device. Therefore, the design freedom of the LCD device 1 is higher than that of the conventional LED backlight LCD device. In particular, the manufacturing cost of the LCD device 1 does not have to be higher than that of a conventional LED backlight LCD device.

  Further, since the backlight drive module 22 is disposed outside the LCD device 1, when the AC adapter 2 is damaged, only the AC adapter 2 may be replaced without disassembling the LCD device 1. Therefore, the repair cost of the LCD device 1 does not have to be higher than that of the conventional LCD device.

  Further, since the backlight drive module 22 can change the maximum value Imax of the backlight current output in accordance with the type of the LCD device 1, the same backlight module 22 is used even if the type of the LCD device 1 is different. Can do.

(Second embodiment)
1, 4 and 5 show an LCD system according to a second embodiment of the present invention. The LCD system according to the second embodiment is a modification of the first embodiment, and instead of the second voltage V2, the backlight on control signal is a predetermined number N (N ≧ 1) during the set period Ts. The predetermined number N is related to the type of the LCD device 1. Further, as shown in FIG. 5, the decoding circuit 221 includes a pulse number detector 2212 instead of the comparison unit 2211.

  The pulse number detector 2212 detects the pulse number N of the pulses of the backlight-on control signal within the set period Ts, and the maximum backlight current control signal is related to the type of the LCD device 1 according to the result of the detection. It is generated as a backlight current control signal. For example, the maximum value Imax of the backlight current output when the number of pulses of the backlight on control signal is 3, 5 or 7 is expressed by Expression 2.

(Third embodiment)
1, 6 and 7 show an LCD system according to a third embodiment of the present invention. The LCD system according to the third embodiment is a modification of the first embodiment, and instead of the second voltage V2, the backlight on control signal outputs a pulse having a predetermined pulse width Tp during the set period Ts. The pulse width Tp is related to the type of the LCD device 1. In addition, the decoding circuit 221 includes a pulse width detector 2213 instead of the comparison unit 2211 as shown in FIG.

  The pulse width detector 2213 detects the pulse width Tp of the pulse of the backlight-on control signal within the set period Ts, and outputs the maximum backlight current control signal according to the result of the detection to the maximum backlight related to the LCD device 1 type. It is generated as a write current control signal. For example, the maximum value Imax of the backlight current output when the pulse width Tp of the backlight on control signal is 1 ms, 2 ms, or 3 ms is expressed by Equation 3.

  As another example, the backlight on control signal may be other combinations except the combinations shown in FIG. 2, FIG. 4, or FIG. 6, but the decoding circuit 221 detects the number of pulses with the comparison unit 2211 (see FIG. 3). It is good also as a structure which has the device 2212 (refer FIG. 5) and the pulse width detector 2213. FIG.

(Fourth embodiment)
1, FIG. 8, and FIG. 9 show an LCD system according to a fourth embodiment of the present invention. The LCD system according to the fourth embodiment is a modification of the first embodiment, in which the video processing module 11 has a maximum voltage V3 associated with the type of the LCD device 1 as a substitute for the second voltage V2. A backlight luminance control signal is further generated. Also, the decoding circuit 221 receives the maximum backlight luminance control signal from the video processing module 11 instead of the backlight on control signal, and the comparison unit 2211 uses the predetermined voltage V3 of the maximum backlight luminance control signal as at least one reference voltage. And the maximum backlight current control signal is generated as the maximum backlight current control signal related to the type of the LCD device 1 according to the comparison result. The maximum backlight current control signal is changed based on the predetermined voltage V3, that is, the type of the LCD device 1.

  For example, the maximum value Imax of the backlight current output when the predetermined voltage V3 of the maximum backlight luminance control signal is 2V, 3.5V, or 5V is expressed by Expression 4.

(Fifth embodiment)
1, 10 and 11 show an LCD system according to a fifth embodiment of the present invention. The LCD system according to the fifth embodiment is a modification of the fourth embodiment, and is different in that the maximum backlight luminance control signal includes a predetermined number N (N ≧ 1) of pulses. Related to the type of device 1. The decoding circuit 221 includes a pulse number detector 2212 (see FIG. 11) instead of the comparison unit 2211. The pulse number detector 2212 detects the pulse number N of the maximum brightness control signal and generates the maximum backlight current control signal as the maximum backlight current control signal related to the type of the LCD device 1 by referring to the result of the detection. To do.

  For example, the maximum value Imax of the backlight current output when the number of pulses N of the maximum backlight luminance control signal is 3, 5 or 7 is expressed by Equation 2 shown above.

(Sixth embodiment)
1, 12 and 13 show an LCD system according to a sixth embodiment of the present invention. The LCD system according to the sixth embodiment is a modification of the fourth embodiment, and differs in that the maximum backlight luminance control signal includes a pulse having a predetermined pulse width Tp. The pulse width Tp is different from that of the LCD device 1. Related to format. The decoding circuit 221 includes a pulse width detector 2213 (see FIG. 13) instead of the comparison unit 2211. The pulse width detector 2213 detects the pulse width Tp of the maximum backlight luminance control signal, and generates the maximum backlight current control signal as the maximum backlight current control signal by the LCD device 1 based on the result of the detection.

  For example, the maximum value Imax of the backlight current output when the pulse width Tp of the maximum backlight luminance control signal is 1 ms, 2 ms, or 3 ms is expressed by Equation 3 as described above.

  Here, as another example, the maximum backlight luminance control signal may be one of the combinations of the maximum backlight luminance control signals shown in FIGS. 8, 10, and 12, and the decoding circuit 221 includes the comparison unit 2211. Note that corresponding combinations of (see FIG. 9), pulse number detector 2212 (see FIG. 11), and pulse width detector 2213 may be included.

(Seventh embodiment)
FIG. 14 shows the configuration of a seventh embodiment of the LCD system according to the present invention. The LCD system according to the seventh embodiment is a modification of the first embodiment. In addition to the configuration according to the first embodiment, a DC / DC connected to the AC / DC conversion module 21 and the video processing module 11 is used. A DC conversion module 13 is further included.

  The AC / DC conversion module 21 converts the AC line voltage into a first DC voltage and a second DC voltage, and converts the first DC voltage and the second DC voltage into the video processing module 11 and the backlight, respectively. It outputs so that electric power may be supplied to the drive module 22. Note that the first DC voltage is, for example, 12V, and the second DC voltage is, for example, 32V.

  The DC / DC conversion module 13 converts the first DC voltage from the AC / DC conversion module 21 into a third DC voltage, and outputs the third DC voltage to supply power to the video processing module 11. Note that the third DC voltage is, for example, 5V. Further, the video processing module 11 does not generate a power saving control signal and does not output it to the AC / DC conversion module 21.

DESCRIPTION OF SYMBOLS 1 Liquid crystal display (LCD) apparatus 11 Video processing module 12 Light emitting diode (LED) backlight module 13 DC / DC conversion module 2 AC adapter 21 AC / DC conversion module 22 Backlight drive module 221 Decoding circuit 2211 Comparison unit 2212 Pulse number detection 2213 Pulse width detector 222 Drive circuit V1 First voltage V2 Second voltage

Claims (7)

A backlight driving signal for driving the LED backlight module of a liquid crystal display (LCD) device including a video processing module for generating a backlight on control signal and a light emitting diode (LED) backlight module is generated. And
A decoding circuit for generating a variable maximum backlight current control signal;
Connected to the decoding circuit and the video processing module to receive the maximum backlight current control signal and the backlight on control signal, and based on the maximum backlight current control signal and the backlight on control signal By generating the backlight driving signal, it is determined whether the backlight on control signal is provided to the LED backlight module, and the backlight current output is related to the maximum backlight current control signal. A drive circuit that outputs a maximum current value of the backlight current output;
A backlight driving module comprising: The backlight on control signal is converted into a first voltage and a second voltage,
The decoding circuit is provided to receive the backlight on control signal from the video processing module;
The decoding circuit according to claim 1, further comprising a comparison unit that compares the second voltage with at least one reference voltage and generates the maximum backlight current control signal according to a result of the comparison. Backlight drive module. The backlight on control signal includes a pulse having a predetermined number of pulses during a set period,
The decoding circuit is provided to receive the backlight on control signal from the video processing module;
The decoding circuit includes a pulse number detector that detects the number of pulses of the backlight-on control signal during the set period and generates the maximum backlight current control signal according to a result of the detection. Item 2. The backlight drive module according to Item 1. The backlight on control signal includes a pulse having a predetermined width during a set period,
The decoding circuit is provided to receive the backlight on control signal from the video processing module;
The decoding circuit includes a pulse width detector that detects the width of the pulse of the backlight-on control signal during the set period and generates the maximum backlight current control signal according to a result of the detection. The backlight drive module according to claim 1. The video processing module further generates a maximum backlight luminance control signal having a predetermined voltage,
The decoding circuit is provided to receive the maximum backlight luminance control signal from the video processing module;
The decoding circuit includes a comparison unit that compares the predetermined voltage of the maximum backlight luminance control signal with at least one reference voltage and generates the maximum backlight current control signal according to a result of the comparison. The backlight drive module according to claim 1. The video processing module further generates a maximum backlight brightness control signal including pulses having a predetermined number of pulses,
The decoding circuit is provided to receive the maximum backlight luminance control signal from the video processing module;
The decoding circuit includes a pulse number detector that detects the number of pulses of the maximum backlight luminance control signal and generates the maximum backlight current control signal according to a result of the detection. Item 2. The backlight drive module according to Item 1. The video processing module further generates a maximum backlight luminance control signal including a pulse having a predetermined width,
The decoding circuit is provided to receive the maximum backlight luminance control signal from the video processing module;
The decoding circuit includes a pulse width detector that detects the width of the pulse of the maximum backlight luminance control signal and generates the maximum backlight current control signal according to a result of the detection. 2. The backlight drive module according to 1.

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