JPS5851453B2 - transmitting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transmitter having a function of reducing the transmission output of a mobile station in accordance with the approaching distance when a mobile station approaches a partner station in mobile communication.

In conventional devices of this type, the power efficiency of the high-frequency power amplifier output circuit was determined according to the maximum output, so the power efficiency at low output was 20% to 30%, and the power efficiency at maximum output was 60%. It was significantly lower than that of

Therefore, even with low output, the expected effect from the viewpoint of power saving was not achieved, and a high efficiency design was required due to battery life issues.

The present invention has been made to solve these drawbacks, and aims to improve power efficiency by reducing transmission output and automatically selecting an optimal output matching circuit. This will be explained in detail.

FIG. 1 shows an embodiment of the present invention, in which 1 is an excitation circuit for a high frequency power amplifier, 2 is a final stage transistor of the high frequency power amplifier, 3 to 6 are output matching circuits, and 7 to 14 are , a PIN diode for switching the aforementioned output matching circuits 3 to 6, 15 a high frequency output coupler, 16 a filter that sends out only the desired wave, and 17 an antenna.

18 is a detector that converts the output of the coupler 15 into DC; 19
is a comparator that compares the output of the wave detector 18 with a reference voltage sent from a control circuit, which will be described later, in order to determine the transmission output.

20 is a voltage controller that increases or decreases the power supply voltage of the high-frequency power amplifier according to the output signal of the comparator 19; 21 is a discriminator that determines the degree of approach of the local station to the other station by measuring electric field strength, etc.; 22; 23 is a controller that has the function of sending out a reference voltage for determining the transmission output based on the signal from the discriminator 21 and at the same time outputting a switching signal for the output matching circuit; 23 is a controller that controls the magnitude of the output voltage of the voltage controller 20; In order to make a determination, the voltage determiner has a multi-stage comparator function, and outputs the output voltage divided into m bits in proportion to the magnitude of the output voltage.

24 is an optimum value judger that selects the optimum matching circuit from the output matching circuit switching signal sent from the controller 22 and the output signal of the voltage judger 23 and sends the signal to the matching switching circuit; 25 is a plurality of n output matching circuits; This is a matching switching circuit that turns the PIN diode ON and OFF to switch the PIN diode.

The operation of this device will be explained below.

Normally, when the mobile station is sufficiently far away from the partner station, the controller 22 outputs a reference voltage and a switching signal so that the transmission output becomes the maximum output, and the matching circuit is selected accordingly.

Next, when the own station approaches the other station, the discriminator 21 sends a discrimination signal to the controller 22 to reduce the transmission output according to the degree of approach, The reference voltage is changed accordingly.

At the same time, a switching signal is sent to the optimum value determiner 24 in order to select the output matching circuit.

The optimum value judger 24 uses a matching switching circuit 25 so that all the output matching circuits it has are sequentially switched.
and simultaneously receives the output of the voltage judger 23 as data.

The voltage determiner 23 has m comparators and 1.2→
It has the function of determining the control voltage level of the automatic transmission output control circuit made in the system of 3 to 6 → 15 → 18 → 19 → 20 → 1°2.

Therefore, by utilizing the fact that the maximum power efficiency point coincides with the minimum control voltage point, the optimum value determiner 24 selects a matching circuit, and a signal is sent out to fix the matching circuit.

As a result, it works to match the circuit with the highest power efficiency.

As explained above, this configuration can save energy and reduce power consumption, and we believe that this will be particularly effective for devices with limited battery life, such as portable mobile devices. It will be done.

Moreover, FIG. 2 shows a specific configuration example of a high frequency power amplifier realized with a relatively simple circuit configuration, in which 101 is a final stage transistor of the high frequency power amplifier, 102 and 103 are choke coils, 104 and 105 are high frequency bypass capacitors, and 106 to 112 are output matching circuit coils and capacitors, 113 and 114 are PIN diodes for circuit switching, 115 is a coupler, and 116 is coupler 1.
15 is an output detection diode, 117 is a smoothing capacitor, 118 is an antenna, and 119 is a controller that sets a reference voltage that determines the transmission output and sends out a circuit switching signal.

120 is a comparator, 121 is a switching transistor,
122 is a voltage control transistor.

The operation of this circuit will be explained below. When the output is high, the switching transistor 121 is turned on, resulting in an output circuit as shown in FIG.

Switching transistor 121 is OFF when the output is low
In operation, as shown in FIG. 4, the load impedance is increased to achieve matching.

Therefore, the power efficiency is much improved compared to achieving low output only by voltage control while maintaining the circuit state of FIG. 3.

FIG. 5 is a graph of output power versus efficiency characteristics obtained by actually measuring the above results.

As is clear from this figure, the power efficiency at low output is significantly improved. Alternatively, it can be selected manually, which can maintain high power efficiency and save power.

In this way, increasing the efficiency of the high-frequency power amplification section in the transmitting device, which also dominates the power consumption of radio equipment, has a significant effect on the lifespan of the radio equipment, and as a result, the battery life of portable equipment etc. Since miniaturization can be achieved, the path to further miniaturization and weight reduction of radio equipment will be opened.

[Brief explanation of drawings]

Fig. 1 is a system diagram of a transmitter according to an embodiment of the present invention, Fig. 2 is a specific wiring diagram of a part thereof, Fig. 3 is an equivalent circuit diagram of an output matching circuit at high output, and Fig. 4 is an equivalent circuit diagram of the output matching circuit at low output, and FIG. 5 is a diagram showing output power versus efficiency characteristics. 1... Excitation circuit of high frequency power amplifier, 2...
...Final stage transistor, 3-6...Output matching circuit, 7-14...Switching PIN diode, 15...Coupler, 16...・
Filter, 17... Antenna, 18...
・Detector, 19... Comparator, 20...
Voltage controller, 21... Discriminator, 22...
・Controller, 23... Voltage judge, 24...
...Optimum value determiner, 25...Matching switching circuit, 101...Final stage transistor, 102
, 103... Choke coil, 104, 105
...High frequency bypass capacitor, 106-11
2... Matching circuit coil and capacitor, 113, 114... PIN diode, 11
5...Coupler, 116...Detection diode, 117...Smoothing capacitor, 118...
...Antenna, 119...Controller, 12
0... Comparator, 121... Switching transistor, 122... Voltage control transistor.

Claims (1)

[Claims] 1. A transmission output section including at least a power amplifying transistor whose transmission output can be varied by a control voltage, an output matching circuit connected to the transmission output section and selected from a plurality of circuits, and a circuit between the output matching circuit and the antenna. a connected power detection means, a comparator whose reference voltage changes according to a required transmission output and which compares the difference with the output of the power detection means, and a comparator which changes the control voltage according to the output of the comparator. and a voltage controller for switching the plurality of output matching circuits so that the output of the voltage comparator is minimized for each of the required transmission outputs, and selecting an output matching circuit that minimizes the control voltage. A transmitting device comprising an optimum value determiner and a matching switching circuit.