JPH0641244U - Power supply circuit for hands-free unit for mobile phones - Google Patents

Abstract

(57) [Abstract] [Purpose] Turning on / off the power of the hands-free unit Eliminating manual operation [Configuration] The power circuit of the hands-free unit for mobile phones is connected to the earphone microphone terminal of the mobile phone via a cable. The input / output terminal 21 and the control switch 26 for detecting that a bias is supplied to the input / output terminal from the earphone / microphone terminal of the mobile phone and turning on the power of the hands-free unit.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a power supply circuit of a hands-free unit for mobile phones.

[0002]

[Prior art]

 With the spread of mobile phones, they have come to be used in various places, and it has become possible to use a hands-free unit to answer calls while working in the car or working. In particular, when using a mobile phone in a car, it is difficult for the driver to talk while driving due to traffic safety problems, and the need for a hands-free unit is strongly desired. ing.

[0003]

[Problems to be solved by the device]

 This conventional hands-free unit is configured to connect the input / output terminals of the hands-free unit to the earphone microphone terminal of the mobile phone, turn on the power switch of the hands-free unit, and start talking. However, the conventional hands-free unit is not designed for connection with a mobile phone, so if you use the hands-free unit in a car, for example, turn it on during a call.・ I had to turn it off, which was not desirable.

[0004]

[Means for Solving the Problems]

 In order to solve such a problem, according to the present invention, an input / output terminal connected to an earphone / microphone terminal of a mobile phone via a cable and a bias is supplied to the input / output terminal from the earphone / microphone terminal of the mobile phone. There is provided a power supply circuit of a handsfree unit for a mobile phone, which is provided with a control switch for detecting the fact and turning on the power supply of the handsfree unit.

[0005]

[Action]

 This makes it possible to make a hands-free call by operating only the mobile phone side when making a call.

[0006]

【Example】

 FIG. 1 shows the basic configuration and power supply circuit of an earphone microphone terminal area of a mobile phone and a hands-free unit connected to the terminal area for explaining an embodiment of the present invention. In the figure, a mobile phone 10 has an earphone microphone terminal 11, and the microphone side of the earphone microphone terminal 11 is connected to an internal circuit (not shown) via a capacitor 12 and an amplifier 13. A resistor 14 is connected between the earphone microphone terminal 11 and the power supply. The earphone side of the earphone microphone terminal 11 is connected to the internal circuit via the amplifier 15. The configuration operation of the mobile phone itself is publicly known, and since the operation is not directly related to the present invention, it will not be described in detail here. A condenser microphone is normally connected to the earphone microphone terminal 11, and a DC bias (for example, about 5 volts) is supplied to operate the condenser microphone in a use state.

Further, in FIG. 1, the hands-free unit 20 includes an input / output terminal 21 into which one of the plugs provided at both ends of the cable 30 is inserted, and an output side of the input / output terminal 21 and a capacitor 22a. The processing circuit 23 is connected to the input side via the capacitor 22b, a microphone 25A and a speaker 25B connected to the processing circuit 23, a power supply 24, and a control switch 26. The processing circuit 23 is a circuit used in a known hands-free unit, and therefore detailed description thereof will be omitted here.

The control switch 26 is a portion characterized by the present invention. The input side is connected to the input / output terminal 21, and when a DC bias voltage appears at the input / output terminal 21, the power supply 24 is turned on and processed. The circuit 23 is activated. In the control switch circuit 26, for example, the base of a transistor 26b is connected via a resistor 26a, and the collector of the transistor 26b closes a switch 24a of a power source 24 to supply a power source 24b such as a battery or a dry cell to a processing circuit 23. Connecting. In this example, the control switch 26a has a resistor 26c between the base of the transistor 26b and the ground, and a resistor 26d between the collector of the transistor 26b and the power source. The emitter of the transistor 26b is grounded. ing.

In such a configuration, the plugs at both ends of the cable 30 are connected to the earphone microphone terminal 11 of the mobile phone 10 and the input / output terminal 21 of the hands-free unit 20, respectively, and the mobile phone 10 is put into use. Then, the control switch 26 of the handsfree unit 20 detects the DC bias voltage appearing at the input / output terminal 21 and turns on the transistor 26b, and its output is sent from the collector of the transistor 26b to the power supply 24. The switch 24a of the power supply 24 is operated. As a result, the hands-free unit 20 is put into operation.

When the mobile phone 10 is in the non-use state or the standby mode, the DC bias does not appear at the input / output terminal 21. As a result, the control switch 26 is turned off and the switch 24a of the power supply 24 is opened. Deactivate the hands-free unit 20. As a result, it is not necessary to turn on / off the power of the hands-free unit, which was required in the past, and the mobile phone can be used even under special conditions such as in a car.

The control switch 26 is not limited to the above-mentioned embodiment, and it goes without saying that various known switch configurations can be applied as they are. This is the same in the configuration of the power supply 24, and in this embodiment, the configuration in which the power supply is turned on / off is described in principle. If the output side is connected, the hands-free unit 20 can be brought into the operating state and the standby state depending on the presence or absence of the output of the control switch 26. In this case, when the cable is removed from the mobile phone, the hands-free unit 20 will be in a standby state.

[0012]

[Effects of the Invention] As described above, by using the power supply circuit of the handsfree unit for a mobile phone according to the present invention, it is possible to make a handsfree call without manually turning on / off the power supply of the handsfree unit. Yes, and when using a device with a power save terminal as a hands-free unit, the operation of the hands-free unit can be set to the operating state / standby state. Further, in this way, the hands-free unit can be used for a long time.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of a power supply circuit of a hands-free unit for a mobile phone according to the present invention.

[Explanation of symbols]

 10 Mobile Phone 11 Earphone Microphone Terminal 12 Capacitor 13 Amplifier 14 Resistance 20 Hands-Free Unit 21 Input / Output Terminal 22 Capacitor 23 Processing Circuit 24 Power Supply 24a Switch 24b Power Supply 25A Microphone 25B Speaker 26 Control Switch 26a Resistance 26b Transistor 26c Resistor 26d Resistance

Claims (1)

[Scope of utility model registration request] 1. An input / output terminal connected to an earphone / microphone terminal of a mobile phone via a cable, and a bias of the earphone / microphone terminal of the mobile phone to the input / output terminal is detected to detect a hands-free unit. A power supply circuit for a hands-free unit for mobile phones, comprising a control switch for turning on the power supply.