JPH0546136U - Mobile radio power switch circuit - Google Patents

Abstract

(57) [Abstract] [Purpose] To eliminate wasteful power consumption of batteries and batteries and to realize a simplified low-cost circuit. [Structure] The power supply line L connecting the power supply unit 2 and the power-supplied unit 3 is opened and closed. The emitter-collector of the switching transistor Q is inserted and connected to the power supply line L, and the base of the switching transistor Q is connected in series to the first switch unit 4 and the second resistor Rs connected in series to the first resistor Rf. It is grounded through the parallel circuit of the two-switch unit 5.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a power supply switch circuit for a portable wireless device that opens and closes a power supply line that connects a power supply unit and a power-supplied unit.

[0002]

[Prior Art]

 FIG. 2 shows a conventional power switch circuit in a portable wireless device. In the figure, reference numeral 22 is a power supply unit (battery or battery), 23 is a power-supplied unit that constitutes the main circuit of the portable wireless device, and the power supply unit 22 and the power-supplied unit 23 are connected by a power switch circuit 20. That is, the emitter-collector of the switch transistor (PNP type) Qo is inserted and connected to the power supply line Ls that connects the power supply unit 22 and the power-supplied unit 23, and the base and emitter of the switch transistor Qo are resistors. It is connected to one contact of the open / close switch 21 via Rb and Re, and the other contact is grounded. Therefore, if the open / close switch 21 is provided in the handset connected to the main body of the wireless device by the connection cable, the power can be turned on / off by remote control. That is, when the open / close switch 21 is turned on, the switch transistor Qo is turned on and the power supply line Ls is closed. When the open / close switch 21 is turned off, the switch transistor Qo is turned off and the power supply line Ls is opened. become.

[0003]

[Problems to be solved by the device]

 By the way, in the case of a portable wireless device, since a battery or a battery is used as a power source unit, it is necessary to suppress unnecessary power consumption as much as possible.

However, in the case of the conventional power supply switch circuit 20 described above, the emitter-collector current of the switching transistor Qo needs to be designed to allow the maximum operating current required by the power-supplied part 23. .. For this reason, since it is necessary to set the base current to a relatively large value, the power consumption of the power switch circuit 20 itself becomes invisible, and eventually there is a problem that wasteful power consumption of the battery and the battery is caused. It was

The present invention solves the problems existing in such conventional technology, eliminates wasteful power consumption of batteries and batteries, and is realized by a very simplified and low-cost circuit. It is an object of the present invention to provide a power switch circuit for a portable wireless device.

[0006]

[Means for Solving the Problems]

 In the present invention, when the power switch circuit 1 of the portable radio that opens and closes the power supply line L that connects the power supply unit 2 and the power-supplied unit 3 is constructed, the emitter-collector of the switching transistor Q is inserted and connected to the power supply line L. In addition, the base of the switch transistor Q is connected in series to the first resistor Rf and the second switch Rs having a resistance value larger than that of the first resistor Rf. It is characterized in that it is grounded through a parallel circuit of the section 5. In this case, it is desirable that the first switch section 4 is constructed by using an open collector inverter 4i, and the second switch section 5 is constructed by using a transistor 5t.

[0007]

[Action]

 In the power switch circuit 1 of the portable wireless device according to the present invention, when both the first switch unit 4 and the second switch unit 5 are turned off, the switching transistor Q is turned off and the power supply line L is opened, that is, The power switch circuit 1 is turned off.

By the way, in the case of a portable wireless device, normally, the reception mode and the transmission mode are switched, but in the reception mode, only the reception circuit operates, so that the power consumption is relatively small, while the transmission mode is In mode, the transmitter circuit is activated, which requires relatively large power consumption.

Therefore, for example, an opening / closing signal “1” is applied to the input side of the inverter 4i so that only the first switch unit 4 is turned on, that is, the connection side of the inverter 4i with respect to the first resistance Rf becomes “0” level. If applied, the base current of the switching transistor Q flows through the first resistor Rf, and the transistor Q is turned on. In this case, since the resistance value of the first resistor Rf is set large, the base current becomes small, and the current flowing through the power supply line L is limited. Therefore, in this case, it is possible to support the reception mode in which the power consumption is low.

On the other hand, if the switching signal “1” is input to the base of the transistor 5t so that the second switch unit 5 is turned on, that is, the transistor 5t is turned on, the base current of the switching transistor Q is set to the second value. It flows through the parallel circuit of the resistor Rs and the first resistor Rf. In this case, since the resistance value of the second resistor Rs is set small, the base current becomes large, and the current flowing through the power supply line L is also large. Therefore, in this case, it is possible to support the transmission mode in which the power consumption is large.

[0011]

【Example】

 Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, the configuration of the power switch circuit 1 according to the present invention will be described with reference to FIG.

Reference numeral 2 is a power supply unit (battery or battery), 3 is a power-supplied unit that constitutes a main circuit of the portable wireless device, and the power switch circuit 1 is connected between the power supply unit 2 and the power-supplied unit 3. Further, Q is a switching transistor (PNP type), and the emitter and collector of the switching transistor Q are inserted and connected to a power supply line L connecting the power supply section 2 and the power-supplied section 3. A resistor Rp is connected between the emitter and base of the switching transistor Q.

On the other hand, the base of the switching transistor Q is grounded via the first resistor R f having a relatively large resistance value and the series circuit of the first switch unit 4. In this case, the first switch unit 4 uses an open collector inverter 4i, and the first resistor Rf is connected to the output side of the inverter 4i. The base of the switching transistor Q is grounded via a second resistor Rs having a relatively small resistance value and a series circuit between the emitter and collector of the transistor 5t forming the second switch section 5. The input side of the inverter 4i and the base of the transistor 5t are connected to the switching signal input sections 11 and 12, respectively. An open / close switch or the like can be connected to the input units 11 and 12, and an open / close signal “1” (high level signal) or “0” (0 level signal) can be selectively given.

Next, a usage method and an operation of the power switch circuit 1 will be described.

First, if the open / close signal “0” is applied to both the input units 11 and 12, the output side of the inverter 4i becomes “1”, while the transistor 5t is turned off. Therefore, the base current ib of the switching transistor Q does not flow, and the switching transistor Q is turned off. Therefore, the power supply line L is opened, that is, the power switch circuit 1 is turned off.

On the other hand, in the reception mode, the opening / closing signal “1” is given to the input section 11, and the opening / closing signal “0” is given to the input section 12. As a result, the transistor 5t maintains the off state, but the output side of the inverter 4i becomes "0", that is, the grounded state, and the base current ib of the switching transistor Q flows through the first resistor Rf and the switching transistor Qt switches. The transistor Q is turned on, and the power switch circuit 1 is turned on with the current flowing through the power supply line L being limited.

On the other hand, in the transmission mode, the opening / closing signal “1” is further given to the input unit 12. As a result, the transistor 5t is turned on and the output side of the inverter 4i becomes "0", so that the base current ib of the switching transistor Q flows through the parallel circuit of the first resistor Rf and the second resistor Rs. That is, the power switch circuit 1 is turned on in a state in which a relatively large current is allowed with respect to the current flowing through the power supply line L. In this case, the base current ib may be passed only through the second resistor Rs by applying the opening / closing signal “0” to the input unit 11 and turning on only the transistor 5t.

Although the embodiments have been described in detail above, the present invention is not limited to such embodiments. For example, the switching transistor may be another switching element such as a FET. Further, each switch section can be replaced with another switch circuit or a switching element. In addition, the detailed circuit configuration and the like can be arbitrarily changed without departing from the gist of the present invention.

[0020]

[Effect of the device]

 As described above, in the power switch circuit of the portable radio device according to the present invention, the emitter and collector of the switch transistor are inserted and connected to the power supply line, and the base of the switch transistor is connected in series to the first resistor. Since the first switch and the second switch are grounded via the parallel circuit of the second switch connected in series, it is possible to eliminate the wasteful power consumption of the battery and the battery, and the extremely simplified low It has the remarkable effect that it can be realized with a cost circuit.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of a power switch circuit of a portable wireless device according to the present invention,

FIG. 2 is an electric circuit diagram of a power switch circuit of a portable wireless device according to a conventional technique,

[Explanation of symbols]

 1 Power Switch Circuit 2 Power Supply Part 3 Powered Part 4 First Switch Part 4i Inverter 5 Second Switch Part 5t Transistor L Feed Line Q Switch Transistor Rf First Resistor Rs Second Resistor

Claims (4)

[Scope of utility model registration request] 1. A power supply switch circuit for a portable radio that opens and closes a power supply line that connects a power supply unit and a power-supplied unit, wherein an emitter-collector of a switching transistor is inserted and connected to the power supply line and a base of the switching transistor is connected. Is grounded via a parallel circuit of a first switch unit connected in series with a first resistor and a second switch unit connected in series with a second resistor. 2. The power switch circuit of a portable wireless device according to claim 1, wherein the resistance value of the first resistor is set larger than the resistance value of the second resistor. 3. The power switch circuit for a portable wireless device according to claim 1, wherein the first switch section uses an open collector inverter. 4. The power switch circuit of a portable wireless device according to claim 1, wherein the second switch section uses a transistor.