JP2001136661A - Power supply controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cut off power supply based on generation of failure in a secondary circuit and a command from a microcomputer. SOLUTION: A switch is interposed between a primary circuit and an AC power supply to make the switch cut off electric power from the AC power supply with a power off signal which a secondary circuit outputs. It is thus possible to cut off main power supply completely automatically in case of some failure, or in the case of remote operation by a user or use of a sleep timer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power supply control device, and more particularly to a power supply control device suitable for use in a television device.

[0002]

2. Description of the Related Art FIG. 5 is a schematic circuit diagram of a conventional power supply control device. In the figure, a push switch 1 is a switch which closes a circuit when a button is pressed and opens when released, and the relay coil 3 is configured to act as an electromagnet by its conduction to close the relay switch 3a. These push switch 1, relay coil 3, relay switch 3a and lamp 2 are provided on one side of a circuit formed in a lattice. The lattice circuit is connected to a power supply via a limit switch 4.

Here, the limit switch 4 is a so-called break contact that normally closes the circuit. When the push switch 1 is pressed, the lamp 2 is turned on and power is supplied to the relay coil 3. When the push switch 1 is released, the contacts of the push switch 1 are opened, but the relay coil 3 opens the relay switch 3a.
Is closed, and power supply to the lamp 2 and the relay coil 3 is maintained. To cut off the power supply to this circuit, the circuit is opened by the limit switch 4.

On the other hand, JP-A-7-95496 discloses that
A power control device for a television device is disclosed. A television device usually includes a circuit for supplying main power for driving the television device, and a circuit for supplying standby power to realize a standby state in which a signal from a remote controller can be received. ing. Here, in the publication, in order to prevent the supply of standby power from being interrupted when the main power supply is interrupted, standby power is supplied from the solar cell when the main power supply is interrupted. .

[0005]

The above-mentioned conventional power supply control device has the following problems. In the former conventional example, the relay switch 3a held by the conduction of the relay coil 3 is opened by a break contact based on physical motion such as the limit switch 4. Therefore, the AC power is obtained in the primary circuit and then converted to DC power,
When used in a television device that supplies the DC power to a secondary circuit, power cannot be shut off based on occurrence of an abnormality in the secondary circuit or a command from a microcomputer.

[0006] In the latter conventional example, the standby power consumed by the AC power supply when the main power is cut off can be set to "0", but the means for cutting off the main power is not shown. It did not respond to abnormalities in the secondary circuit. The present invention has been made in view of the above problems, and an object of the present invention is to provide a power supply control device capable of automatically completely shutting off main power supply in the event of an abnormality or the like.

[0007]

To achieve the above object, according to the present invention, a primary circuit for acquiring power from an AC power supply, and a power supply to the primary circuit driven by DC power and supplied to the primary circuit. A secondary circuit that outputs a predetermined power-off signal for interrupting supply, and a DC power supply unit that converts the power obtained by the primary circuit into a desired DC power and supplies the DC power to the secondary circuit. A switch interposed between the primary circuit and the AC power supply for supplying / cutting power from the AC power supply, and receiving the power supply from the secondary circuit to maintain the conductive state of the switch A switch control circuit capable of shutting off the conductive state by a power-off signal from the secondary side circuit.

In the power supply control apparatus according to the first aspect of the present invention, the power supply control device supplies the power obtained by the primary side circuit to the secondary side circuit, and then controls the primary side circuit by controlling the secondary side circuit. Cut off the power supply to the circuit. For this reason, the primary circuit acquires power from an AC power supply, and the secondary circuit is driven by DC power and a predetermined power-off signal for cutting off the power supply to the primary circuit. Is output. Further, in order to drive the secondary circuit driven by the DC power, the DC power supply means converts the power obtained by the primary circuit into a desired DC power and supplies it to the secondary circuit.

Here, a switch is interposed between the primary circuit and the AC power supply, and the switch supplies and cuts off the power from the AC power supply. The switch control circuit is capable of receiving the supply of power from the secondary side circuit to maintain the conductive state of the switch and to cut off the conductive state by a power-off signal from the secondary side circuit.

That is, once the switch is turned on, power is supplied to the secondary circuit by the DC power supply means, and the switch control circuit maintains the conduction state of the switch. When the power-off signal is output from the secondary circuit, the switch control circuit cuts off the conduction state of the switch. Therefore, power supply to the primary side circuit is completely cut off. As described above, the power-off signal only needs to be output when it is desired to completely cut off the power acquisition in the primary side circuit. The output may be performed when the power is turned off by a timer, or the microcomputer may be configured to detect an abnormal voltage so as to be output when the abnormal voltage is detected.

Here, the primary side circuit may obtain power from an AC power supply, and the DC power supply means may be capable of converting the obtained power into DC power required in the secondary side circuit. Therefore, it is conceivable that the DC power supply means is composed of a switching power supply or the like, and in the primary circuit, power obtained from the AC power supply tap is rectified before supplying power to the switching power supply.

The secondary-side circuit is a circuit driven by DC power, and it is sufficient if the power-off signal for cutting off the power supply to the primary-side circuit can be output. When this is used, this secondary circuit is all devices driven by DC power, such as a one-chip IC and a microcomputer. Further, in this case, the power-off signal can be configured to be output under the control of the microcomputer.

The switch control circuit only needs to be able to maintain the conductive state of the switch and to cut off the conductive state in response to a power-off signal. Item 1 is a power supply control device according to Item 1, wherein the switch control circuit supplies power to the coil from the secondary side circuit and maintains the switch in a conductive state by the attraction force of the coil.

In the invention according to claim 2 configured as described above, the switch control circuit has a coil. Here, the coil can be made to act as an electromagnet by supplying power, and power is supplied from the secondary side circuit to the coil, and the switch is turned on by the attractive force of the coil. That is, the same principle as that of the above-described relay switch is used to secure the conduction state of the switch.

[0015] When the conduction state of the switch is ensured by using the coil as described above, there are various configurations for interrupting the conduction state.
According to a second aspect of the present invention, in the power supply control device according to the second aspect, the switch control circuit shuts off power supply to the coil by a switching transistor that is turned off by the power-off signal.

In the third aspect of the present invention, the switch control circuit includes a switching transistor. The switching transistor is turned off by the power-off signal, and the power supply to the coil is cut off by the off operation. That is, according to the switching transistor, it is possible to easily configure a switch that is turned on / off in response to a predetermined signal output under the control of the microcomputer. In the present invention, the power supply to the coil is turned on / off. By controlling, the conduction state of the switch can be easily cut off.

According to a fourth aspect of the present invention, as an example of another configuration for interrupting the conduction state, the switch control circuit supplies power to the coil in the power supply control device according to the second aspect. The power supply circuit includes a diode to which the anode is connected, and the cathode is set to a low level in response to the power-off signal so that power is not supplied to the coil.

In the invention according to claim 2 configured as described above, the switch control circuit includes a diode whose anode is connected to a circuit for supplying power to the coil. Then, the cathode of this diode goes to a low level in response to the power-off signal, and when the cathode goes to the low level, power is supplied to the subsequent stage through this diode so that power is not supplied to the coil. It has become.

That is, when an anode of a diode is connected to a predetermined position of a circuit for supplying power to the coil and the cathode is kept at a high level, the diode is connected to a circuit for supplying power to the coil. Although there is no effect, when the cathode is set to the low level, the connection point can be set to the low level so that power is not supplied to the circuit for supplying power to the coil. As a result, the switch in which the conductive state is maintained by the coil is interrupted.

[0020]

As described above, according to the present invention, the power is turned on / off in the primary circuit by opening / closing the switch in response to the power-off signal from the secondary circuit. Therefore, it is possible to provide a power supply control device capable of completely completely shutting off the main power supply at the time of abnormality or the like. Claim 2
According to the invention, a switch provided in the primary circuit and the AC power supply can be opened and closed with a simple configuration.

Further, according to the invention of claim 3,
With a simple configuration, it is possible to provide a switch that is turned on / off in response to a power-off signal. Claim 4
According to the invention, a switch that is turned on / off in response to a power-off signal with a simple configuration can be provided.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a power supply control device according to an embodiment of the present invention in a claim correspondence diagram.
In the figure, a primary circuit A1 is supplied with power from an AC power supply, and a circuit between the primary circuit A1 and the AC power supply is opened and closed by a switch A4. The DC power supply means A3 converts the AC power obtained by the primary circuit A1 into a predetermined DC power and supplies the DC power to the secondary circuit A2. The secondary circuit A2 is driven by the DC power output from the DC power supply means A3. The secondary circuit A2 outputs a power-off signal for interrupting power supply to the primary circuit, and this power-off signal is supplied to the switch control circuit A5. The opening and closing of the switch A4 is controlled by this switch control circuit.

FIG. 2 is a main part circuit diagram of a power supply control device according to one embodiment of the present invention. In FIG. 1, the primary side circuit 10 includes an AC input line for obtaining AC power from an AC 100 V power supply and a rectifier circuit 11, and a switch 40 described later is interposed on the AC input line. The output line of the rectifier circuit 11 is input to a switching power supply 30 while being grounded via a capacitor. Output. Further, in this embodiment, a case is shown in which the present power supply device is used for a television device, and the secondary circuit is all devices driven by DC power, such as a one-chip IC and a microcomputer.

The output line of the switching power supply 30 is input to a secondary circuit via a diode and a capacitor having one grounded. In this sense, the switching power supply 30 constitutes the DC power supply means. The output line of the switching power supply 30 is branched, and one of the output lines is input to a switch control circuit 50 that controls opening and closing by the switch 40. That is, the switch 40 is configured by connecting a push switch 41 and a relay switch 42 in parallel, and the relay switch 42 is opened and closed by a coil 51 provided in the switch control circuit 50 acting as an electromagnet.

The push switch 41 is configured so that the contact is closed by a pushing operation of the user and the contact is opened by releasing the pushing operation. After the pushing operation, power is supplied to the coil 51 and the relay switch 42 Are closed, and the conduction state of the primary circuit 10 is maintained until the power of the coil 51 is cut off thereafter. Coil 5
1 is provided in a switch control circuit 50. The switch control circuit 50 includes the coil 51 and a switching transistor T for controlling power supply / interruption to the coil 51.
The switching transistor Tr2 is turned on / off in response to r1 and the power-off signal.

That is, the output line from the switching power supply 30 input to the switch control circuit 50 is branched in the switch control circuit 50, and one of the output lines is connected to the switching transistor Tr via the resistor and the coil 51.
1 is supplied to the collector of the switching transistor Tr, and the other of the switching transistor Tr
1 base. Here, the collector of the switching transistor Tr2 is connected in the middle of the bias line with respect to the base of the switching transistor Tr1, and the emitter is grounded. Further, the power-off signal is input to the base via a resistance element for applying a predetermined bias.

Therefore, while the power-off signal is not being output, the switching transistor Tr2 is off, and the switching transistor Tr1 is appropriately biased and is on. As a result, while the power is supplied to the switch control circuit 50 by the output line from the switching power supply 30 and the power-off signal is not output, the power is continuously supplied to the coil 51. That is, the contacts of the relay switch 42 are kept closed.

When the power off signal is output to turn on the switching transistor Tr2, the collector of the switching transistor Tr2 falls to ground. Therefore, the switching transistor Tr
No proper bias is applied to the base of No. 1 and the switching transistor Tr1 is turned off. Therefore,
The supply of power to the coil 51 is also stopped, the contact of the relay switch 42 is opened, and the AC
Power acquisition from 100V is also cut off. As a result, the supply of the main power is completely cut off. As described above, the switching transistor Tr2 is turned on and the switching transistor Tr1 is turned off by outputting the power-off signal under the control of the secondary side circuit. However, in this embodiment, the user directly receives the main power. It is also possible to cut off the supply.

That is, a push switch 52 is provided in parallel with the collector terminal and the ground terminal of the switching transistor Tr2, and when the user pushes the push switch 52, the switching transistor Tr2 is directly turned on. The collector terminal and the ground can be short-circuited. According to the pushing operation by the push switch 52, the same operation as when the switching transistor Tr2 is turned on can be performed, and the supply of the main power is completely shut off in the same manner as the above operation.

FIG. 3 is a timing chart showing the operation of the power supply control device having the above-described configuration, showing the ON / OFF states of the main elements and the H / L levels of the signals. In the figure, the user pushes the push switch 41 at time t1.
Is pressed, that is, turned on, the primary side circuit 1
0 is maintained, and power is supplied from the AC 100 V power supply to the same primary side circuit. Then, the switching power supply 3
A predetermined DC power is supplied to the secondary-side circuit through the switch 0, and the DC power is also supplied to the switch control circuit 50 to apply an appropriate bias to the switching transistor Tr1 to turn on the switching transistor Tr1.

When the switching transistor Tr1 is turned on, power is simultaneously supplied to the coil 51, and the coil 51 acts as an electromagnet. Therefore, the relay switch 42 is turned on. At this time, even if the user cancels the pushing operation of the push switch 41 at time t2, the power is continuously supplied to the primary circuit 10 and the secondary circuit because the relay switch 42 closes the circuit, and the switching is performed. A state in which the relay switch 42 is also closed because the transistor Tr1 remains on;
That is, it remains on.

In this state, a predetermined DC power is continuously supplied to the secondary circuit, and a predetermined function is performed as a television device. Here, at time t3, when the user performs an operation of turning off the main power by remote control operation, reaches the time instructed by the sleep timer, or detects an abnormal voltage by the microcomputer, the power-off signal Is output.

When the power-off signal is output, at the same time t
3, a predetermined appropriate bias is applied to the switching transistor Tr2, and the switching transistor Tr2
Turns on. Therefore, the switching transistor Tr
2 is almost at the ground level, so that an appropriate bias is not applied to the switching transistor Tr1. As a result, at time t4, the switching transistor Tr1 is turned off and the relay switch 42 opens the circuit, and at the same time, the power supply to the primary circuit is cut off. As a result, power supply to all circuits thereafter is completely stopped.

In this embodiment, the switching transistor Tr1 is interposed between the coil 51 and the ground, and the on / off of the switching transistor Tr1 is controlled by the on / off of the switching transistor Tr2. However, here, it is sufficient that the acquisition / cutoff of power in the primary side circuit can be controlled according to the power-off signal, and the circuit configuration is various. FIG. 4 is a circuit diagram of a switch control circuit 50 according to another embodiment. In the other embodiment, the configuration of the switch control circuit 50 is partially different from that of the above-described embodiment. Instead of diode D
1 is connected.

The diode D1 has its anode terminal connected to the switch control circuit, and its cathode is normally at a high level. That is, when the cathode is at the high level, the diode D1 has no effect on the connection line to the base terminal of the switching transistor Tr1. Therefore, in this state, when a predetermined DC power is supplied from the switching power supply to the switch control circuit 50, the switching transistor Tr1 is appropriately biased to turn on the switching transistor Tr1. That is, the relay switch 42 is kept on.

The cathode level of the diode D1 is set to a low level in response to the power-off signal. When the cathode of the diode D1 goes to a low level, the switching transistor Tr
The switching transistor Tr1 is turned off without an appropriate bias being applied in the same manner as when the switching transistor 2 is turned on.
Therefore, the power supply to the coil 51 is cut off, the relay switch 42 is turned off, and the power supply to the primary circuit is completely stopped.

As described above, in the present invention, the switch is interposed between the primary circuit and the AC power supply, and the power from the AC power supply by the switch is cut off by the power-off signal output from the secondary circuit. . Therefore, the main power supply can be completely cut off automatically when an abnormality occurs, when the user operates the remote controller, or when the sleep timer is used.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims of a power supply control device according to an embodiment of the present invention.

FIG. 2 is a main part circuit diagram of a power supply control device according to one embodiment of the present invention.

FIG. 3 is a timing chart of main elements and signals during operation of the power supply control device.

FIG. 4 is a circuit diagram of a switch control circuit according to another embodiment.

FIG. 5 is a schematic circuit diagram of a conventional power supply control device.

[Description of Signs] 10 Primary circuit 11 Rectifier circuit 30 Switching power supply 41 Push switch 42 Relay switch 50 Switch control circuit 51 Coil Tr1, Tr2 Switching transistor

Claims (4)

[Claims] A primary circuit for obtaining power from an AC power supply; a secondary circuit driven by DC power and outputting a predetermined power-off signal for cutting off power supply to the primary circuit. A DC power supply means for converting the power obtained by the primary circuit into a desired DC power and supplying the DC power to the secondary circuit, and the AC power supply being interposed between the primary circuit and the AC power supply. A switch for supplying / interrupting power from the switch, receiving the power from the secondary circuit, maintaining the conductive state of the switch, and switching the conductive state by a power-off signal from the secondary circuit. A power supply control device, comprising: a switch control circuit that can be shut off. 2. The power supply control device according to claim 1, wherein the switch control circuit supplies power from a secondary circuit to the coil, and maintains the switch in a conductive state by an attraction force of the coil. A power supply control device, characterized in that: 3. The power supply device according to claim 2, wherein the switch control circuit interrupts power supply to the coil by a switching transistor that is turned off by the power-off signal. Control device. 4. The power supply control device according to claim 2, wherein the switch control circuit includes a diode having an anode connected to a circuit for supplying power to the coil, and the power-off signal. A power supply control device, wherein power is not supplied to the coil by setting the cathode to a low level in response to the power supply.