JPH0514588Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a control circuit for transmitting output power (hereinafter referred to as transmitting output) in a mobile radio device, particularly a mobile phone.

(Prior Art) FIG. 2 is a block diagram of a power control circuit showing a conventional example.

In the figure, reference numeral 1 denotes an amplifier circuit, which amplifies an amplifier input A using microwaves, for example, and outputs a transmission output B. +V is its power supply voltage. A detection circuit 2 serves as a detection circuit, which detects the transmission output B and outputs a detection output C logarithmically proportional to the level of the transmission output B. 3 is a level dividing circuit which divides the level of the detected output C into a plurality of level signals C1 to C6 by a plurality of resistors R1 to R5. VR1 and VR2 are variable resistors for level adjustment, and R0 is a fixed resistor for level adjustment. 4 is an analog multiplexer, which inputs the level signals C1 to C6 of the level division circuit 3 to its input terminal IN, selects one of the level signals C1 to C6 as appropriate according to the control command D, and outputs it to the output terminal OUT. Take it out. +5V is the power supply voltage,
VE is a grounded 0 potential. 5 is a comparison circuit,
The level signals C1 to C6 selected from the output terminal OUT of the analog multiplexer 4 are input to the (-) terminal, and the (+) terminal is set to the reference level E by the reference level power supply 6, and the level signals C1 to C6 selected from the output terminal OUT of the analog multiplexer 4 are input. Comparing the signal with the reference level E, the mutual deviation output F
is negatively fed back to the amplifier circuit 1. Note that Rf is a negative feedback resistance. 7 is a Zener diode for absorbing a surge in the detection output C that occurs during a transient response of the amplifier circuit 1.

In the circuit of FIG. 2, by selecting the level signals C1 to C6 of the level division circuit 3 using the control command D, the amplifier circuit 1 adjusts the level of its transmission output B to each predetermined level according to the selection. The gain is adjusted so that

(Problem to be solved by the invention) However, devices using the above circuit are easily affected by variations and fluctuations in the characteristics of the detection circuit 2, and therefore it is difficult to obtain a device that has excellent characteristics with little variation and fluctuations. However, there were problems in that it caused manufacturing difficulties and decreased yield.

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a power control circuit that has a simple circuit configuration, improves manufacturing yield, and facilitates mass production.

(Means for Solving the Problem) In order to solve the above problem, the present invention provides a power supply that controls the output level of an amplifier circuit that is driven by a power supply voltage, amplifies input power, and outputs transmission output power. In the control circuit, a power supply voltage correction circuit that obtains a correction output according to a deviation between the power supply voltage level and a reference level, a level division circuit that divides the output level of the power supply voltage correction circuit into a plurality of levels, and the level division circuit. an analog multiplexer that selectively takes out each level signal divided by the circuit; and a drive circuit that amplifies the level signal taken out from the analog multiplexer and outputs a control signal for controlling the output of the amplifier circuit. Equipped with

(Function) According to the present invention, the power supply voltage correction circuit obtains a correction output according to the deviation between the power supply voltage and the reference level, and the level division circuit divides this output level into a plurality of levels, and these level signals are The transmission output level can be controlled by selectively extracting the level signal with an analog multiplexer, amplifying the extracted level signal with the drive circuit, and outputting a control signal to the amplifier circuit.

(Embodiment) FIG. 1 is a block diagram of a power control circuit showing an embodiment of the present invention, and parts having the same structure as the conventional one are denoted by the same reference numerals. That is, 1 is an amplifier circuit,
3 is a level division circuit, and 4 is an analog multiplexer.

10 is an operational amplifier 10a, resistors Ra, Rb, Rc,
In the power supply voltage correction circuit including Rd and negative feedback resistor Rf as components, a voltage obtained by dividing +5V by resistor Ra and resistor Rb is input to the (+) terminal of operational amplifier 10a as reference voltage Verf. On the other hand (-) terminal,
A voltage obtained by dividing the power supply voltage +V of the device to a value smaller than +5V by a resistor Rc and a resistor Rd is input as a fluctuating voltage V _M. The operational amplifier 10a is the reference voltage
A corrected reference output G that has been amplified and corrected is output according to the deviation between Verf and the fluctuating voltage _VM .

11 is an operational amplifier 11a, a transistor TR,
The drive circuit includes a negative feedback resistor Rg as a component, and level signals C1 to C6 selected from the output terminal OUT of the analog multiplexer 4 are input to the (+) terminal of the operational amplifier 11a, and a transistor TR is input to the (-) terminal. is connected to the emitter of Rf via a negative feedback resistor Rf. The emitter of the transistor TR is connected to the output control terminal of the amplifier circuit 1, the collector is connected to the power supply voltage +V, and the base is connected to the output side of the operational amplifier 11a, which outputs an output control signal H to the amplifier circuit 1. . With this configuration, the output control signal H from the emitter of the transistor TR is fed back to the (-) terminal of the operational amplifier 11a to
This eliminates fluctuations in the output control signal H due to temperature fluctuations in the TR.

Next, the operation of the above configuration will be explained. The amplifier circuit 1 amplifies the amplifier input a and outputs the transmission output B, but the level of the transmission output B is affected by fluctuations in the power supply voltage +V. That is, when the power supply voltage +V decreases, the transmission output B also decreases accordingly, and conversely, when the power supply voltage +V increases, the transmission output B also decreases.
will also be lower.

The power supply voltage correction circuit 10 uses a variable voltage V _M obtained by dividing the above-mentioned power supply voltage +V and a reference voltage obtained by dividing +5V.
Amplify according to the deviation from Verf and correct the standard output G
is output to the level division circuit 3. In the level division circuit 3, this correction reference output G is connected to a plurality of resistors R1 to
Divide into multiple level signals C1 to C6 by R5,
Output to analog multiplexer 4. Level signal C1~ input to analog multiplexer 4
C6 is a control command D from the control unit (not shown)
and output to the drive circuit 11.
The drive circuit 11 amplifies the level signal inputted by the operational amplifier 11a and outputs it as an output control signal H to the output control terminal of the amplifier circuit 1. This makes it possible to output the transmission output B at a stable level without being affected by fluctuations in the power supply voltage +V.

(Effects of the invention) As explained above, according to the invention, in the power control circuit that controls the output level of an amplifier circuit that is driven by a power supply voltage, amplifies input power, and outputs transmission output power, A power supply voltage correction circuit that obtains a correction output according to the deviation between the power supply voltage level and a reference level; a level division circuit that divides the output level of the power supply voltage compensation circuit into a plurality of levels; and a drive circuit that amplifies the level signal taken out from the analog multiplexer and outputs a control signal for controlling the output of the amplifier circuit. Transmission output level can be controlled without using conventional detection circuits. Therefore, manufacturing difficulties caused by variations and fluctuations in characteristics can be avoided and yields can be improved, and mass production can be expected.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a power control circuit showing an embodiment of the present invention, and FIG. 2 is a block diagram of a power control circuit showing a conventional example. DESCRIPTION OF SYMBOLS 1... Amplifier circuit, 2... Detection circuit (detection circuit), 3... Level division circuit, 4... Analog multiplexer, 5... Comparison circuit, 10... Power supply voltage correction circuit, 11... Drive circuit.

Claims (1)

[Claims for Utility Model Registration] In a power control circuit that controls the output level of an amplifier circuit that is driven by a power supply voltage, amplifies input power, and outputs transmission output power, a deviation between the power supply voltage level and a reference level. a power supply voltage correction circuit that obtains a correction output according to the power supply voltage correction circuit; a level division circuit that divides the output level of the power supply voltage correction circuit into a plurality of levels; and a level division circuit that selectively divides each level signal divided by the level division circuit. A power control circuit comprising: an analog multiplexer for extracting the output; and a drive circuit for amplifying the level signal extracted from the analog multiplexer and outputting a control signal for controlling the output of the amplifier circuit.