JPH0695652B2 - Transmitter / receiver automatic power interruption circuit - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic power supply / interruption circuit for a transmitter / receiver, and more particularly to supplying a power supply voltage to the transceiver only when an input signal is applied to save power when the transceiver is not operating. The present invention relates to an automatic power interruption circuit of a transmitter / receiver capable of performing.

[0002]

2. Description of the Related Art Portable electric devices including transceivers such as cordless phones, car phones and pagers depend on batteries for their power supply voltage, so that the battery life is kept as long as possible or a small capacity battery is used for practical use. In order to obtain sufficient usage time, it is necessary to reduce the power consumption of the circuit as much as possible. However, in a portable electric device including this type of transceiver, it is uncertain when the input signal is supplied, and therefore in the conventional device, the transceiver was always placed in a standby state.

Therefore, in such a device, in the standby state,
There is a problem in that current consumption that cannot be ignored occurs, and for this reason, a battery with a large battery capacity used as a power source must be used, or the battery must be frequently charged.

Conventionally, the power saving in this kind of portable equipment has been considered by reducing the current consumption of the circuit element as much as possible. For example, instead of the conventional general electric circuit by 5V driving, a 3V driving element is used. Efforts such as using were made.

[0005]

However, even if such a power saving action of the circuit element is performed as effectively as possible, since it is kept in a standby state for a long time, it is unavoidable that the accumulated current consumption increases. In the past, the current situation is that reduction in size and weight of the device is hindered by such unnecessary current consumption in the standby state.

As such a transceiver, in addition to the above-mentioned various portable devices, it is widely used in a radio transceiver of a CD player or a tape recorder using an emergency radio receiver or a wireless microphone, for example. .

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to provide an improved automatic power supply disconnecting circuit for a transceiver used in various fields in order to significantly reduce the current consumption during the conventional standby.

[0008]

In order to achieve the above object, the present invention provides a transmission control circuit for subjecting an input signal to a predetermined transmission process and outputting the signal to a transmission circuit, and the transmission control circuit and the transmission circuit. A power switch circuit that intermittently supplies the power supply voltage, a piezoelectric element that resonates with an input signal in a predetermined frequency range to output a piezoelectric voltage, and the piezoelectric voltage of the piezoelectric element is supplied to a gate terminal, and turns on when a predetermined piezoelectric voltage is applied. An FET switching element that operates to turn on the power switch circuit is provided, and power is automatically supplied to the transmission control circuit and the transmission circuit for a predetermined time when a predetermined input signal is applied.

Further, a reception control circuit for subjecting an input signal to a predetermined reception process and outputting it to a reception circuit, a power supply switch circuit for intermittently supplying the power supply voltage to the reception control circuit and the reception circuit, and a predetermined frequency region. A piezoelectric element that resonates with an input signal and outputs a piezo voltage, and a piezo voltage of the piezoelectric element is supplied to a gate terminal and is turned on when a predetermined piezo voltage is applied to turn on the power switch circuit.
A switching element is included, and power is automatically supplied to the reception control circuit and the reception circuit for a predetermined time when a predetermined input signal is applied.

[0010]

Therefore, according to the present invention, the input signal is monitored in the standby state of the device by the piezoelectric element which does not consume current, and the piezo voltage of this piezoelectric element is detected by the FET switching element. It is possible to reduce the current consumption of the transceiver to almost zero.

The piezoelectric element of the present invention is in a standby state where it can always resonate with an input signal in a predetermined frequency range, and the input signal can be continuously monitored without power consumption.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a preferred embodiment of an automatic power interruption circuit of a transmitter according to the present invention. In the figure, the transmitter constitutes a transmitter of a wireless CD player, for example.

A stereo input signal reproduced from a CD player is supplied to the input terminal 10 and distributed to the right input line 11 and the left input line 12, respectively.

Both input signals are supplied to the transmission and transmission control circuit 14 via the smoothing circuit 13, are subjected to high frequency modulation by the transmission control circuit, and then propagated from the antenna 15 of the transmission circuit to the receiver.

As is well known, the transmission control circuit includes a frequency modulation circuit including a local oscillation circuit and a mixing circuit and a high frequency amplifier, and a desired modulation action is given by a predetermined carrier frequency.

Therefore, according to such a wireless CD player transmitter, the CD player and the headphones can be completely separated to listen to music.

A feature of the present invention is that in such a transmitter, when there is no input signal supplied to the input terminal 10, the power supply voltage to the transmission and transmission control circuit 14 is automatically cut off. It is to obtain a desired power saving effect.

As is apparent from FIG. 1, the power supply for the device is shown at 16 and normally a battery is used to make the CD player transmitter portable.

In the embodiment, the power source 16 has its positive electrode connected to the transmission and transmission control circuit 14,
On the other hand, the ground side of the transmission and transmission control circuit 14 is grounded via the power switch circuit 17, and as a result, when the power switch circuit 17 is in the OFF state, the power supply voltage is not supplied to the transmission and transmission control circuit 14. Completely blocked.

A feature of the present invention is that the power supply switch circuit 17 is turned on only when a predetermined input signal is supplied, and a piezoelectric element 18 is provided as a monitoring means for this purpose. The piezoelectric element 18 is made of piezoelectric ceramics, and for example, ferroelectric ceramics containing barium titanate, lead zirconate or lead titanate as a component is suitable, and these ceramics are polarized to form a piezoelectric element. .

In the present invention, lead zirconate titanate ceramics (PZT) is particularly preferable.

The piezoelectric element 18 can be formed, for example, from a low-priced element which is usually used as a speaker, and the piezoelectric ceramic is firmly adhered and fixed on a substrate such as brass, and one side thereof is fixed. The terminal 18a provided is grounded, while three electrodes 18 are provided on the other surface side.
b, 18c and 18d are fixed.

The electrode 18b is connected to the right signal input line 11 via the damping resistor 19, while the electrode 1b
8c is the left signal input line 12 via the attenuation resistor 20.
It is connected to the.

Therefore, when either one of the input signals is supplied to the input terminal 10, the piezoelectric element 18 can generate resonance vibration and generate a piezo voltage at the output electrode 18d. Of course, in this embodiment, the resonance frequency of the piezoelectric element 18 is set within the frequency range of the input signal supplied from the CD player, and the piezoelectric element 18 responds only to the desired input signal. And in the example,
Input electrodes 18 are separately provided for the left and right input signals.
b and 18c are provided, the piezoelectric element 1 of the embodiment
Reference numeral 8 can output the piezo voltage only with at least one of the input signals.

According to the present invention, by turning on the power switch circuit 17 by the piezo voltage of the piezoelectric element 18, the transmission and transmission control circuit 14 can be put in the power supply voltage supply state only when the input signal is supplied. , In fact, the input signal itself from the CD player is intermittent,
Since the piezo voltage output from the piezoelectric element 18 also becomes an intermittent voltage signal, a circuit for holding this signal for a predetermined time is required. Further, in the present invention, the piezo voltage is used as it is in the power switch circuit 17. Since it is extremely weak for use as an input signal, this piezo voltage is applied to the FET switching element 21 with a delay action.

That is, the piezo voltage generated from the electrode 18d is connected to the gate terminal of the FET switching element 21, and this gate terminal is grounded via the resistor 22. The FET switching element 21 has almost no current consumption when the gate input is not supplied, and as a result, the current consumption in the input signal monitoring apparatus according to the present invention can be almost zero.

The resistor 22 is composed of a protective resistor having a high resistance value, and when an overcurrent is generated thereby, it is leaked to protect the circuit. For example, this protection resistor 22 is 5M
It is preferable to set it to about ohm.

In the embodiment, the source of the FET switching element 21 is grounded via the delay circuit 25 consisting of the resistor 23 and the capacitor 24. As a result, the piezoelectric element 18 once receives the input signal and outputs the piezo voltage to the FET. When it is supplied to the gate terminal of the switching element 21, the FET switching element 21 continues to be turned on for a predetermined time, and even when the piezo voltage of the piezoelectric element 18 disappears during this time, this on state can be maintained.

The time constant of the delay circuit 25 is arbitrarily set according to the type of the input signal. For example, when listening to music with a CD player or the like, a signal holding period of about 5 seconds is suitable.

The drain of the FET switching element 21 is further amplified by an amplifier 26 via a variable resistor 27 and supplied to one input terminal of a comparator 28 via a voltage dividing circuit. The voltage of the power supply 16 is supplied to the other input of the comparator 28, and as a result, the comparator 2 is in a state where the FET switching element 21 is kept in the ON state.
A comparison signal is output from 8 and is inverted by the inverter 29 before being supplied to the gate input of the preceding-stage transistor 30.

Of course, in the present invention, the output of the inverter 29 may be supplied to the gate input of the power switch circuit 17 described above. However, in the present embodiment, the output of the front stage transistor 30 further has a variable timer. It is supplied to the output of the power switch circuit 17 through the hold circuit 31.

The hold circuit 31 can set the hold time only by changing the resistance value of the variable resistor 32, and if necessary, the FET switching element 21.
It is possible to hold the ON operation state of the preceding stage transistor 30 for a predetermined time separately from the delay circuit 26 connected to the source terminal of the.

Therefore, the power switch circuit 17 continues to be in the ON operation state for an arbitrary time after the input signal is applied, and in the normal case, the signal from the CD player is intermittently applied to the piezoelectric element 18. It is possible to continuously maintain the power supply state of the transmission and transmission control circuit 14 while the intermittent signal is supplied.

As described above, according to this embodiment, when the piezoelectric voltage of the piezoelectric element 18 exceeds a predetermined value, F
The ET switching element 21 is turned on, and the power switch circuit 17 is turned on for a predetermined holding time determined at this time, so that the transmitter can be kept in an operating state.

When the input signal is not supplied for a predetermined time, the FET switching element 21 is turned off, and as a result, the power switch circuit 17 is turned off after a predetermined hold time has elapsed.

As described above, according to the transmitter of this embodiment, only the piezoelectric element 18 and the FET switching element 21 are in the standby state for monitoring the input signal.
The piezoelectric element 18 does not consume current, and
Since the T switching element 21 is also of the voltage drive type, its current consumption is almost zero as is well known. Therefore, the total current consumption of these two elements can be almost zero even in the input signal monitoring standby state.

As described above, according to this embodiment, C
It is possible to configure a power supply disconnecting circuit that supplies a power supply voltage to the transmission and transmission control circuits only when an input signal from the D player is applied. As these transmitters, not only the transmitter of the wireless CD player shown in the embodiment but also any other transmitters such as mobile phones, cordless phones, car phones, etc. can be used.

On the other hand, the present invention can be applied not only to the transmitter but also to the receiver, and is particularly suitable as a portable receiver for an automobile telephone or a cordless telephone.

That is, these receivers are preferably driven by a small battery in order to enhance their portability, and on the other hand, they must always be in the reception standby state, and therefore the current consumption in the reception standby state is reduced. A significant reduction is desired.

FIG. 2 shows a receiver of a cordless telephone. In the figure, the signal received by the antenna 40 is supplied from the resonance circuit 41 to the reception control circuit 42.

As is well known, the reception control circuit 42 performs a predetermined demodulation operation, and supplies the output to the reception circuit 43 to cause the user to perform a desired communication operation through, for example, a speaker 44, or a predetermined communication operation. Causes the display unit to perform a display function.

Also in such a receiver, similarly to the transmitter of FIG. 1 described above, the reception control circuit 42 and the reception circuit 4 are provided.
3, a power supply voltage is supplied from a power supply 116, and a power supply switch circuit 117 is connected to the negative side of the power supply 116.

Also in the receiver shown in FIG. 2, the input signal supplied from the antenna 40 and the resonance circuit 41 is the piezoelectric element 11.
8 and the piezoelectric elements 118 to F
ET switching element 121, amplifier 126, comparator 1
28, the inverter 129, and the power switch circuit 1
Since the circuit configuration between 17 is almost the same as in FIG. 1,
100 is added to the reference numeral of each member, and detailed description thereof is omitted.

In FIG. 2, the input signal to the piezoelectric element 118 is a single-channel signal unlike the stereo signal of FIG. 1, so the piezoelectric element 118 in the embodiment of FIG. 2 has only a single input electrode 118b.

Further, in FIG. 2, when the present embodiment is used as a receiver of a cordless telephone or a car telephone,
After the reception control circuit 42 is supplied with power by the ON operation of the power switch circuit 117 from the supply of the input signal, the hold signal 42a of the reception control circuit 42 is supplied to the gate input of the power switch circuit 117, and the reception operation thereafter. The power switch circuit 117 is kept in the on-operation state until the above is completed.

Therefore, in this embodiment, unlike the embodiment in the transmitter shown in FIG. 1, the delay circuit 25 connected to the source of the FET switching element 121 is eliminated, and similarly, the preceding stage transistor of FIG. 30 and the hold circuit 31 are also removed.

Therefore, according to the present embodiment, the piezoelectric element 11
After the input signal is applied to 8, the receiving circuit 43 and the receiving control circuit 42 receive the power supply voltage supply only until the reception action is completed, and the power supply voltage supply is cut off in other portions, so that the receiver It is possible to obtain a remarkable power saving effect.

[0049]

As described above, according to the present invention,
In the transmitter or the receiver, when the input signal is not applied, the supply of the power supply voltage to the transmission / reception circuit and the transmission / reception control circuit is completely cut off, so that the current consumption of the transceiver can be remarkably reduced.

Further, since the piezoelectric element is used for monitoring the transmission / reception input signal, there is an advantage that the consumption current in this monitoring circuit can be made almost zero and the input signal can be monitored with high response.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment in which an automatic power interruption circuit according to the present invention is applied to a transmitter.

FIG. 2 is a circuit diagram showing an embodiment in which an automatic power interruption circuit according to the present invention is applied to a receiver.

[Explanation of symbols]

 14 transmission and transmission control circuit 16,116 power supply 17,117 power supply switch circuit 18,118 piezoelectric element 21,121 FET switching circuit 42 reception control circuit 43 reception circuit

Claims (2)

[Claims] 1. A transmission control circuit that performs a predetermined transmission process on an input signal and outputs the signal to a transmission circuit, a power supply switch circuit that intermittently supplies a power supply voltage to the transmission control circuit and the transmission circuit, and a predetermined frequency range. A piezoelectric element that resonates with an input signal and outputs a piezoelectric voltage, and a piezoelectric voltage of the piezoelectric element is supplied to a gate terminal, and an FET switching element that is turned on when a predetermined piezoelectric voltage is applied to turn on the power switch circuit. And an automatic power interruption circuit of a transmitter, which automatically supplies power to the transmission control circuit and the transmission circuit for a predetermined time when a predetermined input signal is applied. 2. A reception control circuit for performing a predetermined reception process on an input signal and outputting the reception signal to a reception circuit, a power supply switch circuit for intermittently supplying a power supply voltage to the reception control circuit and the reception circuit, and a predetermined frequency region. A piezoelectric element that resonates with an input signal and outputs a piezoelectric voltage, and a piezoelectric voltage of the piezoelectric element is supplied to a gate terminal, and an FET switching element that is turned on when a predetermined piezoelectric voltage is applied to turn on the power switch circuit. And an automatic power interruption circuit of the receiver, which automatically supplies power to the reception control circuit and the reception circuit for a predetermined time when a predetermined input signal is applied.