JPS63200214A - Voltage stabilizing power supply circuit - Google Patents

Abstract

PURPOSE:To stabilize the output voltage and to reduce the scale of a power supply circuit device by connecting a resistance between the input and output terminals of a voltage stabilizing circuit via an open/close means. CONSTITUTION:The power is supplied to a load 5 from a battery 1 via a voltage stabilizing circuit 3. An open/close means 10 consists of a transistor TR9, the base bias resistances 7 and 8 for the TR9, and a TR driving transmission switch 6. A resistance 11 is connected in series to an emitter-collector circuit of the TR9 provided into the means 10 and then connected in parallel to the circuit 3. In such a constitution, the current capacity of the circuit 3 is compensated and increased by a due amount by the current which is shunted to a resistance from a power supply and by closing the controllable means 10.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a voltage stabilizing power supply circuit used as a power source for small equipment, particularly portable radio equipment.

[Conventional technology]

FIG. 4 is a block diagram of the periphery of a conventional voltage stabilized power supply circuit. In the figure, 1 is a battery, 3 is a voltage stabilizing circuit, 5 is a load, and 2 and 4 are the input terminal and output terminal of the voltage stabilizing circuit 30, respectively. This voltage stabilizing circuit 3 is often implemented as an IC.

The general characteristics of this conventional voltage stabilizing power supply circuit are shown in FIG. In the same figure, the horizontal axis is the load 5
The vertical axis represents the output voltage of the voltage stabilization circuit 3, 1 represents the maximum current capacity value of the voltage stabilization circuit 3, and vO represents the stabilized output voltage value of the voltage stabilization circuit 30. It shows.

At the current capacity value Iet, the output voltage is a constant value V.

It can be seen that K is maintained.

[Problem that the invention seeks to solve]

When the voltage stabilizing power supply circuit of the prior art as described above is used in a portable radio device, it may cause a problem because the load current of the power supply differs significantly between the time of transmission and the time of reception.

In other words, the load current at the time of reception is set, and the load current at the time of transmission is set! If the load current 11 is set approximately at the center of the flat characteristic as shown in Fig. 5, the output voltage value Vo will always remain at a constant value even if the load current m increases or decreases somewhat during reception. However, when transmitting, the load current I! is the current capacity value! Since the voltage may exceed 0, the current capacity of the entire circuit has been increased by using a plurality of voltage stabilizing power supply circuits. Furthermore, when - number of voltage stabilizing power supply circuits are used, it is necessary to use a voltage stabilizing power supply circuit having a large current capacity and having a sufficiently larger load current It during transmission.

As described above, in any conventional method, the size is large (whichever method is used), and it is also necessary to take measures against heat generation, which has been an obstacle in downsizing the device.

[Means for solving problems]

In the voltage stabilizing power supply circuit according to the present invention, the input terminal and the output terminal of the voltage stabilizing circuit are connected by a resistor using switching means that can be turned on and off.

[Effect]

By closing the controllably switching means, the current capacity of the voltage stabilized power supply circuit is captured by the current shunted from the power supply to the resistor, and increases by a corresponding amount.

[Embodiment] FIG. 1 shows an embodiment in which the voltage stabilizing power supply circuit of the present invention is applied to a portable radio device. Note that the same reference numerals are used for the same or corresponding parts as in FIG. 4, and the explanation thereof will be omitted.

In the figure, the opening/closing means 10 is composed of a transistor 9, a resistance 7.8 for pace bias, and a transmission switch 6 for driving the transistor. This opening/closing means 1
In the emitter collector circuit of transistor 9 in 0,
A resistor 11 is connected in series, and this series circuit is connected between the input terminal 2 and the output terminal 4 so as to be in parallel with the voltage stabilizing circuit 3.

Next, to explain the operation, when receiving data from a portable radio, the transmitting switch 6 of the opening/closing means 10 is turned off, so the transistor 9 is turned off because no pace current flows, and the voltage stabilizing circuit The input terminal 2 and output terminal 4 of No. 3 are in an open state. The maximum current that can be passed through the load 5 at this time is determined by the current capacity value of the voltage stabilizing circuit 3 itself, and the characteristics between its output voltage and load current are as shown in FIG. The current capacity value is still large enough for the load current Ill during reception.

On the other hand, when the portable radio is transmitting, the transmission switch 6 of the opening/closing means 10 is turned on, so the transistor 90 pace is biased by the resistor 7 and the resistor 8, a pace current flows, and the transistor 9 is turned on. Therefore, a closed circuit is established between the input terminal 2 and the output terminal 4 of the voltage stabilizing circuit 30 via the resistor 11. The maximum current that can be passed through the load 5 at this time is from the battery 1 to the resistor 11. The current I divided into and the current capacity value of the voltage stabilization circuit 3 itself! Sum with 0 (
I11. ), its output voltage, and load current characteristics are shown in FIG. In Figure 3, the horizontal axis represents the load current, and the vertical axis represents the output voltage of the voltage stabilized power supply circuit. represents the input voltage value of the voltage stabilizing circuit 3. As shown in the figure, the output voltage is stabilized at vo while the load current is from I to I@t.

Load current during transmission! Even if the current capacity value IO of the voltage stabilizing circuit 3 is exceeded, the excess amount is compensated for by the current I that is shunted to the resistor 11, and the current capacity of the power supply circuit as a whole has increased. .

Therefore, even if the load current increases during transmission and exceeds the current capacity of the voltage stabilizing circuit 3, the current capacity can be increased by appropriately selecting the value of the resistor 11 and connecting it between its input and output terminals. This makes it possible to respond to the increase in

Further, FIG. 2 shows another embodiment according to the present invention using a plurality of resistors and a plurality of opening/closing means. In the figure, the same or corresponding parts as in FIG. 1 are denoted by the same reference numerals, and the explanation thereof will be omitted.

In addition to the series circuit of the switching means 10 and the resistor 11, FIG. They are connected in parallel between each other.

By the way, by connecting the input and output terminals of a voltage stabilizing circuit with a resistor, it is possible that the voltage stabilizing effect due to power supply ripple etc. will be impaired, but in general, small devices such as portable radios have almost no power supply ripple. Since it uses batteries, there are no issues with this. therefore,
This has the effect of reducing the number of minutes required for voltage stabilization circuits, especially in devices that use a battery as a power source.

Although the above embodiments have been described as applied to portable wireless devices, they can also be applied to cordless telephones and the like.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, by connecting a resistor between the input and output terminals of the voltage stabilizing circuit using a switching means, the load current exceeds the current capacity of the voltage stabilizing circuit itself. Even in this case, it is possible to obtain a stable output voltage over the entire load current range with one voltage stabilizing circuit, and it is also possible to downsize the device. When a plurality of resistors are used, a current capacity suitable for the current situation can be obtained by selectively connecting them using switching means.

Furthermore, when the voltage stabilizing power supply circuit according to the present invention is applied to a portable radio, even if the power supply circuit is adapted to the low load current during reception of the portable radio, it will not be possible to cope with the high load current during transmission. , the device can be made smaller.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the voltage stabilized power supply circuit according to the present invention, FIG. I2 is a block diagram showing another embodiment, and FIG. , a graph showing the characteristics between the output voltage and load current of the voltage stabilizing circuit 3, FIG. 4 is a block diagram showing the vicinity of the voltage stabilizing power supply circuit according to the prior art, and FIG. 3 is a graph showing the characteristics between the output voltage and load current of the stabilized power supply circuit 3. FIG. 1...Battery, 3...-Voltage stabilization circuit, 5
...-Load, 6...Transmission switch, ? , 8.11
, 13, 15...Resistor, 9...Transistor,
10,12.14@...Opening/closing means.

Claims (1)

[Claims] A voltage stabilizing power supply circuit in which a switching means that can be turned on and off and a resistor are connected in series between the input terminal and output terminal of the voltage stabilizing circuit.