JP5098620B2 - Power switch circuit - Google Patents

Description

  The present invention relates to a power switch circuit of an electric device, and more particularly to a power switch circuit that consumes no power during standby and has excellent operability.

  In recent years, energy saving of all electric devices has been further advanced. Moreover, the movement is not limited to energy saving at the time of operation of the electric device, but has been developed to a state where the electric device is waiting for an operation signal, that is, energy saving of electric power required at the time of standby. As prior art documents of such a power switch circuit for saving energy during standby, there are, for example, the following.

JP 2003-284337 A

A conventional power switch circuit will be described below. FIG. 4 is a configuration example of a conventional power switch circuit. The switch 1 connects the power plug 2 and the power circuit 3 in the on state. The switch 6 is a mechanical relay, a semiconductor relay or the like. The power plug 2 is usually commercially available and is connected to a commercial power source. The power supply circuit 3 converts a commercial power supply into direct current, and is composed of electrical components. However, the circuit scale is large and the power consumption during operation and standby is large.

The switch control circuit 4 is connected to the secondary side of the power supply circuit 3. The switch 5 is a momentary operation type, that is, a switch that operates only while the button is pressed. The switch 6 is controlled to be turned on or off by the switch control circuit 4. The load 7 is a circuit that operates using the power switch circuit having the above-described configuration as a power source, and includes, for example, a circuit or a device.

  FIG. 5 is a configuration example of a circuit in which power consumption during standby is reduced. In FIG. 5, the same components as those in FIG. The auxiliary power circuit 8 is connected to the power plug 2 via the switch 1. The auxiliary power supply circuit 8 is a power supply circuit for supplying power to the switch control circuit 4, and uses a power supply circuit that is smaller than the power supply circuit 3 serving as a main power supply circuit.

  FIG. 6 is a configuration example of a circuit in which power consumption during standby is zero. The power plug 2 is connected to the power supply circuit 3 via the switch 1, and the switch 5 is connected to the switch 1 in parallel. When the switch 5 is turned on, the switch control circuit 4 operates via the power supply circuit 3, and the switch 1 is turned on under the control of the switch control circuit 4. After the switch 1 is turned on, the energization is maintained even if the activation switch 5 is turned off.

In order to turn off the power supplied to the load 7, a signal is output from the load 7 to the switch control circuit 4, and the switch control circuit 4 turns off the switch 1. That is, even if the switch 5 is turned off, the power cannot be turned off.

As described above, the conventional power switch circuit uses the auxiliary power circuit 8 to reduce power consumption when the power is turned off.

However, in the electrical equipment, when the load 7 controls on / off of the power supply itself, or when the power supply is turned on / off using a small switch as described with reference to FIGS. Thus, it is necessary to supply power to a circuit that controls on-off even when the power is off (standby), and to operate the circuit. However, these methods have the following problems.

  First, in order to turn on the power supply circuit 3 in the circuit of FIG. 4, it is necessary to turn on the switch 1 serving as the main power supply in advance. In order to realize this, if the switch 1 is deleted and the power supply circuit 3 is directly connected to the power plug 2, it is not necessary to turn on the switch 1 in advance, but the power supply circuit 3 is always energized.

  Then, since the switch control circuit 4 is connected to the power supply circuit 3, standby power is consumed even if the switch 6 is off. Furthermore, since the power supply circuit 3 is made for the purpose of supplying power to the load 7, the scale of the circuit is large, and the standby power of the power supply circuit 3 itself is also large. Therefore, it is difficult to reduce power during standby in the configuration of FIG.

  In the circuit of FIG. 5, the auxiliary power supply circuit 8 having a small circuit scale and low power consumption during standby supplies power to the switch control circuit 4, so that the power supply circuit 3 and the switch control circuit 4 as shown in FIG. Power consumption can be reduced compared to supplying power to However, electric power for operating the auxiliary power supply circuit 8 is still required.

  On the other hand, in the circuit of FIG. 6, since the switch 1 and the switch 5 are off and the power supply circuit 3 is also disconnected from the power plug 2 when the device is off, no standby power is consumed. However, since the start switch 5 can only perform the operation of turning on the power of the apparatus, there is a problem that the operability is poor.

  The present invention has been made in view of these problems, and an object of the present invention is to provide a power switch circuit that consumes zero power during standby and has excellent operability.

In order to solve such a problem, the invention described in claim 1
In a power switch circuit including a power supply circuit for supplying power to the device circuit,
A switch for supplying power from a commercial power source to the power circuit;
A startup switch connected in parallel with this switch;
A switch control circuit that starts operation by a signal output from the power supply circuit when the activation switch is turned on, and switches the switch on and off;
A latch circuit that outputs a signal to the switch control circuit when a signal is input from the power supply circuit;
When the operation starts, the switch control circuit monitors a signal output from the latch circuit. When this signal is at a high level, the switch control circuit determines that it is a start-up sequence, turns on the switch, and the signal output from the latch circuit is When the level is low, it is determined that the power is turned off and the switch is turned off.

The invention of claim 2, in the power switching circuit of claim 1, wherein,
The second start switch is connected to the primary side of the power supply circuit together with the start switch, and the state of the second start switch is transmitted to the switch control circuit via a photocoupler.

Furthermore, the invention according to claim 3 is the power switch circuit according to claim 1 or 2 , wherein
A backup battery is connected to the switch control circuit, a timer is connected to the backup battery, and the switch control circuit is activated by the backup battery when a predetermined time elapses with this timer.

  The present invention has the following effects. A latch circuit is provided and the start signal or power off sequence is determined by the monitor signal, so the power can be turned on and off with one switch, and the power switch circuit itself can turn off the power. It becomes. In addition, since an auxiliary power circuit is not required, a power switch circuit in which standby power when the power is turned off is zero can be provided.

A configuration example of the power switch circuit of the present invention will be described below with reference to FIG. The switch 1 connects the power supply circuit 3 to the power plug 2 in the ON state. The switch control circuit 4 controls the switch 1.

A switch 10a is connected to the switch 1 in parallel. The switch 10 a is a momentary operation type switch. When the switch 10 a is turned on, the switch control circuit 4 operates via the power supply circuit 3, and the switch 1 is turned on by the control of the switch control circuit 4. After the switch 1 is turned on, the energization is maintained even if the activation switch 10a is turned off.

Similarly to the switch 10a, the switch 10b is a momentary operation type switch and is connected to the switch control circuit 4. When the switch 10b is turned on, an off signal is input to the switch control circuit 4. Specifically, the switch control circuit 4 is grounded and the power supply is turned off. Note that the switch 10a and the switch 10b may be configured by using two-circuit momentary switches. In the following description, it is assumed that the switches 10a and 10b are always turned on and off simultaneously in the circuit of FIG.

  The LATCH circuit (latch circuit) 11 sets the monitor signal 103 to a high level when the output voltage 102 of the power supply circuit 3 rises. When the trigger signal 104 is input from the switch control circuit 4, the monitor signal 103 is held at a low level, and this holding state is canceled when the voltage of the output signal 102 of the power supply circuit 3 becomes a certain value or less.

  Next, an operation when the power supply circuit 1 of FIG. 1 is turned on will be described with reference to FIG. Here, FIG. 2 is a waveform diagram for explaining the operation of FIG. 1, but the following operation means an operation within the period of reference numeral 300 in FIG. 2 unless otherwise specified.

First, when the activation switches 10a and 10b are turned on (reference numeral 200 in FIG. 2), a voltage is input to the power supply circuit 3 (reference numeral 201), and the output signal 102 of the power supply circuit 3 rises (reference numeral 202). Is input to the switch control circuit 4, and the switch control circuit 4 operates.

  When the operation is started, the switch control circuit 4 confirms the state of the monitor signal 103 output from the LATCH circuit 11 (reference numeral 203). When the monitor signal 103 is at a high level (reference numeral 207), it is determined as an activation sequence, the main power holding signal 105 is output (reference numeral 205), and the switch 1 is turned on.

  At the same time, the switch control circuit 4 generates a trigger signal 104 (reference numeral 204), and the LATCH circuit 11 holds the monitor signal 103 at a low level (reference numeral 208). Further, since the switch 1 is turned on even when the switch 10a is turned off, the main power holding signal 105 remains at the high level (reference numeral 205), and the power supply of the apparatus is kept on.

  Subsequently, an operation when the power of the apparatus is turned off will be described. In the following description, an operation within a period 310 in FIG. 2 is meant unless otherwise specified. First, in a state where the power supply of the apparatus is turned on (reference numeral 205), when the activation switches 10a and 10b are turned on (reference numeral 209), an off signal 106 is input to the switch control circuit 4 by the activation switch 10b. Is done. The switch control circuit 4 detects that the OFF signal falls (reference numeral 212), and confirms the state of the monitor signal 103 output from the LATCH circuit 11.

  When the LATCH circuit monitor signal 103 is at a low level (reference numeral 210), the switch control circuit 4 determines that the power supply is off, sets the main power holding signal 205 to a low level (reference numeral 211), and turns off the switch 1. When the switch 1 is turned off and the start switch 10 is turned off, the apparatus is turned off.

  The monitor signal 103 output from the LATCH circuit 11 is intended to prevent the operator from accidentally turning on the power even though the operator intends to perform the power-off sequence. If the LATCH circuit 11 is not provided, the switch 1 is turned off when the switch 10 is turned on in the power-off sequence. However, in this state, since it cannot be distinguished from the startup sequence, the power-on sequence is entered again and the power is turned off. I can't.

  For this reason, the LATCH circuit 11 is added, and the activation sequence and the power-off sequence are discriminated by the monitor signal 103.

  As described above, the LATCH circuit 11 is provided and the start signal or the power-off sequence is determined by the monitor signal 103. Therefore, the power can be turned on / off with one switch 10a, 10b, and the power switch circuit. The power can be turned off by itself. In addition, since an auxiliary power circuit is not required, a power switch circuit in which standby power when the power is turned off is zero can be provided.

Next, application examples of the present invention will be described. FIG. 3 is a block diagram of an application example of the present invention. The same components as those in FIG. The start switch 12 is a two-circuit momentary operation type switch, one of which is connected in parallel with the main power switch 1 and the other connected to the photocoupler 13a (photocoupler LED side).

  The photocoupler 13b, that is, the phototransistor side of the photocoupler is connected to the switch control circuit 4. The backup battery 14 is connected to the switch control circuit 4.

  That is, the difference between FIG. 1 and FIG. 3 is that both start switches 12 are moved to the primary side of the power supply circuit and the state of the switch 12 is transmitted to the secondary side via the photocouplers 13a and 13b. Two points are that the backup battery 14 is attached to the switch control circuit 4.

  Incidentally, in the configuration of FIG. 1, two activation switches 10 a and 10 b are connected to the input side and the output side of the power supply circuit 3, respectively. Usually, since the input side of the power supply circuit 3 is connected to a commercial power source and the output side (secondary circuit) needs to be insulated from the input side (primary circuit), insulation is also provided between the starting switches 10a and 10b. As a result, the switch itself becomes large.

  In the configuration of FIG. 3, when the start switch 12 is turned on while the apparatus is turned on, the state of the start switch 12 is transmitted to the switch control circuit 4 via the photocoupler 13. Therefore, since all the circuits of the start switch 12 can be connected to the input side (primary side) of the power supply circuit 3, the start switch 12 can be reduced in size.

  In the configuration of FIG. 3, the backup battery 14 is connected to the switch control circuit 4 so that the apparatus can be turned on without operating the start switch 12.

  That is, in the configuration of FIG. 1 described above, the device power can be turned “off” by the load 7 without operating the activation switches 10a and 10b. In order to do this, the start switch had to be operated.

  According to the configuration of FIG. 3, it is possible to control the switch control circuit 4 and the switch 1 with the power of the backup battery 14 by using a control element with low power required for driving, such as a semiconductor relay, for the switch 1. Become. For this reason, a timer circuit or the like (not shown) is mounted on the switch control circuit 4, and the switch control circuit 4 is operated using the backup battery 14 at the set time so that the device can be turned on.

  As described above, in the application example of FIG. 3, since the state of the start switch 12 is transmitted to the secondary side using the photocouplers 13a and 13b, the start switch 12 can be downsized, and the power switch circuit itself can be downsized. Can be Further, since the backup battery 14 is provided, not only can the apparatus 7 be turned off by the load 7, but also the apparatus can be turned on.

It is an example of a structure of the power switch circuit of this invention. It is a wave form diagram explaining the operation | movement of FIG. It is a block diagram of the application example of this invention. It is a structural example of the power switch circuit by a prior art. It is an application example of the power switch circuit by a prior art. It is a 2nd application example of the power switch circuit by a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Switch 2 Power plug 3 Power supply circuit 4 Switch control circuit 7 Device circuit 10a Switch 10b Switch 11 LATCH circuit 12 Start switch 13 Photocoupler 14 Backup battery

Claims (3)

In a power switch circuit including a power supply circuit for supplying power to the device circuit,
A switch for supplying power from a commercial power source to the power circuit;
A startup switch connected in parallel with this switch;
A switch control circuit that starts operation by a signal output from the power supply circuit when the activation switch is turned on, and switches the switch on and off;
A latch circuit that outputs a signal to the switch control circuit when a signal is input from the power supply circuit;
When the operation starts, the switch control circuit monitors a signal output from the latch circuit. When this signal is at a high level, the switch control circuit determines that it is a start sequence, turns on the switch, and the signal output from the latch circuit is A power switch circuit characterized in that when it is at a low level, it is determined as a power-off sequence and the switch is turned off . The second start switch is connected to the primary side of the power supply circuit together with the start switch, and the state of the second start switch is transmitted to the switch control circuit via a photocoupler. The power switch circuit according to claim 1 . A backup battery is connected to the switch control circuit, a timer is connected to the backup battery, and the switch control circuit is activated by the backup battery when a predetermined time elapses with the timer. Item 3. The power switch circuit according to any one of Items 1 and 2 .

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