JPH0545003Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The present invention relates to a drive circuit for a self-holding relay.
In particular, the present invention relates to a drive circuit for a self-holding relay that is provided in combination with a remote control IC in electronic equipment such as a television receiver having a remote control function.

[Conventional technology]

For electronic devices such as televisions that have a remote control function, the remote control transmitter can control various functions on the electronic device itself, such as channel selection and volume adjustment, as well as turning the power on and off. It also allows for control. In order to turn on the power of an electronic device that is turned off, it is necessary to keep the power on the receiver side of the remote control turned on even if the power of the electronic device is turned off. Provide a power source that cannot be turned off by a switch,
The remote control receiver is configured to receive power supply from this power source.

[Problem that the idea aims to solve]

In conventional electronic equipment, as mentioned above, a power supply that cannot be turned off by the power switch on the electronic equipment itself is used as the power source for the remote control receiver, so the power line to the electronic equipment [distribution line]
As long as the power supply from the remote control transmitter side is not cut off, the remote control receiver of the electronic device main body remains active, and therefore, the power of the electronic device main body can be turned on by remote control operation from the remote control transmitter side. However, if the power supply to the electronic device is cut off due to some reason, such as a power outage, this specially installed power supply for the remote control receiver will also be turned off, and when the power supply starts again, the remote control receiver side will be turned off. The state of the control relay may not return to its original state, and the remote control receiver may not operate properly and remote control operations from the remote control transmitter side may become impossible. This idea was made in consideration of the above points, and in electronic equipment whose power switch is turned on and off by remote control, there is a possibility that the power supply line (distribution line) may be disconnected when the equipment is moved or due to a power outage. An object of the present invention is to provide a drive circuit for a self-holding relay that can prevent the relay from malfunctioning when power supply is stopped and power supply is restarted.

[Means to solve the problem]

In order to solve the above-mentioned problem, in this invention, a first terminal A to which a first voltage V1 is always applied;
a self-holding relay 2; a first switching element 3 connected between the first terminal A and the self-holding relay 2 and controlling a current for turning off the self-holding relay 2; , a capacitor 6 connected in series to the self-holding relay 2 and having the other end grounded; and a capacitor 6 connected to the first terminal A and having the other end connected to the control electrode of the first switching element 3. a second resistor connected between the other end of the high resistor 7 and the ground to control the current for turning on the self-holding relay 2;
a switching element 4, a diode 10 connected between the connection point between the relay 2 and the first switching element 3, and the connection point between the high resistance 7 and the second switching element 4; When the holding relay 2 is on, a second voltage V2 that rises slower than the first voltage V1 and falls faster is applied to the second terminal B;
a resistor 8 whose one end is connected to the terminal B of the switching element 3 and whose other end is connected to the control electrode of the first switching element 3; a power terminal P whose output is "L" (roll bell) when the power is turned on; A remote control control circuit 1 having a set terminal S for receiving a signal for switching the output of the power terminal P to "H" (high level), the power terminal P of the remote control control circuit 1 being connected to the second switching element 4. The set terminal S constitutes a drive circuit for a self-holding relay connected to the control electrode and the set terminal S connected to the resistor 8.

[Effect]

When the power supply to the electronic device is stopped due to a power outage while the self-holding relay 2 is in the ON state, and the power supply is restarted, the first switching element is In response to this, a current flows in the direction to turn off the relay 2, but the current due to the control current from the second power source, which rises slowly, does not flow, and is sufficient to turn off the self-holding relay 2. Since there is no current, it remains in the on state. Additionally, if the power supply is stopped due to a power outage or the like while the self-holding relay 2 is in the OFF state, and the power supply is restarted, the second switching element for turning on the self-holding relay 2 will be inoperative. , remains off. As a result, even if the power supply is temporarily interrupted due to a power outage, etc., and then the power supply is restarted, the self-holding relay 2 will maintain its previous state as it is, making it possible to prevent the self-holding relay from malfunctioning. become.

【Example】

The present invention will be described below with reference to embodiments shown in the drawings. 1 is a remote control control circuit having a set terminal S and a power terminal P; 2 is a self-holding relay that performs on/off operations; and 3 and 4 are switching devices constituting first and second switching elements, respectively. Transistors 5, 7, 8, 9, 11, 1
4 is a resistor, 6 is a capacitor, and 10, 12, and 13 are diodes. A and B are terminals, voltage V1 is always applied to terminal A when the electronic device is connected to the power line [distribution line], and voltage V2 is applied to terminal B only when relay 2 is on. . The rise of this voltage V2 is slower than the voltage V1 at terminal A, and the fall is faster. Furthermore, the power terminal P of the control circuit 1 is configured to be at the "L" (low level) level when the power is turned on.
The "L" state can be changed by applying a signal to the set terminal S or by a command from an external remote control transmitter.Furthermore, the power terminal P is set to "H" (high level). After becoming
“L” by command from external remote control transmitter
It is configured so that it can be changed to The control circuit 1 may be configured by a combination of gate circuits, and may include a microcomputer or the like. In the self-holding relay 2, the discharge current of the electric charge charged in the capacitor 6 flows through the relay 2 and the diode 1.
0, collector of switching transistor 4
It turns on when the current flows through the emitter, and turns off when the current flows from terminal A through the switching transistor 3, resistor 5, relay 2, and capacitor 6. The magnitude of the current in this OFF operation depends on the base current of the switching transistor 3, and is therefore related to the magnitudes of the resistors 7 and 8, but in this invention, only the terminal A is The voltage is applied and the base current IB7 of the transistor 3 flowing through the resistor 7 cannot turn off the relay 2, and the voltage V at the terminal A
1 and terminal B voltage V2 rise together, and base currents IB7 and IB8 of transistor 3 flowing through resistors 7 and 8 are set so that a current sufficient to turn off relay 2 can flow. . Next, the operation of the circuit will be explained. First, the operation when the self-holding relay 2 is in the on state will be explained. In the drive circuit in which the relay 2 is in the on state, when the main body of the electronic device is connected to the power supply line and the voltage V1 of the terminal A rises, voltage is applied to the collector of the transistor 3 and the voltage for switching is applied via the resistor 7. The base current IB7 of the transistor 3 flows, and the transistor 3
turns on, and current IR1 flows from terminal A to transistor 3, resistor 5, relay 2, and capacitor 6.
flows. The direction of current flow at this time is relay 2
The current flows in the direction of turning off the transistor 3, but is caused only by the base current IB7 of the transistor 3 (via the resistor 7) due to the voltage V1 at the terminal A only.
IR1 cannot turn off relay 2. Therefore, since relay 2 remains on, voltage is applied to terminal B via relay 2, but the rise of voltage V2 at terminal B is slower than the rise of voltage V1 applied to terminal A. Therefore, the voltage V2 at the terminal B rises after the voltage V1 at the terminal A rises. At this time, the capacitor 6 is already charged by the current generated when only the voltage V1 at the terminal A rises, and the base current of the transistor 3 does not flow through the diode 12. On the other hand, the voltage V to terminal B
2 is transmitted to the set terminal S of the control circuit 1 via the resistor 8 and the resistor 9, and the power terminal P of the control circuit 1 becomes "H" (high level). When the power terminal P of the control circuit 1 becomes "H",
The base current of transistor 4 flows, turning on transistor 4, and the on-current of relay 2 (charge of capacitor 6 is discharged through relay 2, diode 10, and collector/emitter of the transistor) flows, but naturally relay 2 is in the on state. It remains as it is. Further, since transistor 4 is turned on, the base of transistor 3 is grounded, no base current flows, and transistor 3 is turned off. At this time, current flows through the transistor 4 from the terminal A through the resistor 7. At the same time, the current from terminal B also flows to resistor 8, diode 12, transistor 4, and ground, so the potential of set terminal S decreases and becomes "L" state, but power terminal P remains "H" state. (The power terminal P is brought into the "L" state only by a command from a remote control transmitter (not shown)), and the transistor 4 maintains the on state. Even if the power supply from the power supply line (distribution line) is stopped for some reason while the self-holding relay 2 is in the on state and the power supply is restarted, it will perform the same operation as described above and will maintain its self-holding status. Since the ON state of the self-holding type relay 2 will be maintained as it is, there is no possibility that the self-holding type relay 2 will malfunction. This state is the on state of relay 2. Next, the case where relay 2 is turned off will be explained. When the relay 2 is in the on state as described above, in order to turn off the relay 2, a predetermined key provided on a remote control transmitter (not shown) is operated. By this operation, a signal for resetting the power terminal is input to the control circuit 1, and the power terminal P of the control circuit 1 becomes "L" and the transistor 4 is turned off. Then, base current IB7 flows from terminal A to the base of transistor 3 through resistor 7, and base current IB8 flows from terminal B through resistor 8.
flows, and the base current flows to the base of transistor 3.
A base current equal to the sum of IB7 and base current IB8 flows, turning on transistor 3, and current IR2 flows from terminal A through transistor 3, resistor 5, relay 2, and capacitor 6. At this time, the current IR2 is the base current IB7, 8 of the transistor 3 (base current IB7 and base current IB
8), the current is sufficient to turn off the relay 2, and the relay 2 is turned off. If power is started to be supplied to the electronic device via the power line (distribution line) while the self-holding relay 2 is in the OFF state, the base current of the transistor 3 flows through the resistors 7 and 11, so the transistor 3 is in the on state, and a corresponding current (in the off direction) flows through relay 2 (at this time, since relay 2 is off, voltage V2 is not applied to terminal B, and the voltage from the terminal B side is (No base current flows to transistor 3), which naturally maintains the off state. Further, the capacitor 6 is charged by the current at this time. In order to turn on the relay 2 from the above-mentioned off state, the power terminal P of the control circuit 1 is set to "H" by operation from the remote control transmitter. As a result, transistor 4 is turned on, and as mentioned above, the base of transistor 3 is grounded and no base current flows, turning transistor 3 off, and current flows through capacitor 6, relay 2, diode 10, transistor 4, and relay 2. is turned on. Now, regarding when relay 2 is in the off state,
If the power supply from the power line (distribution line) is stopped for some reason, the power terminal P of the control circuit 1
remains “L” and transistor 4 remains off, so the charge on capacitor 6 is transferred to relay 2,
It is discharged toward terminal A via diode 10 and resistor 7. However, since the current in the resistor 7 is limited, sufficient current does not flow to turn on the relay 2, so the relay 2 will not turn on. The relay can be turned on and off arbitrarily if voltage V1 is applied to terminal A and voltage V is applied to terminal B.
Only when 2 is added.

[Effect of the idea]

As described above, according to the present invention, even if the power supply to the device is temporarily stopped due to moving the electronic device or a power outage, etc., and then restarting the power supply, the state of the relay that was before the power supply was stopped is maintained. It is possible to reliably prevent malfunction of the relay.

[Brief explanation of the drawing]

The drawing is a circuit diagram of one embodiment of the present invention. 1... Control circuit, 2... Relay, 3, 4... Transistor, 6... Capacitor, 7, 8, 9, 1
1, 14...Resistor, 10,12,13...Diode.

Claims (1)

[Claims for Utility Model Registration] First terminal A to which the first voltage V1 is constantly applied
a self-holding relay 2; a first switching element connected between the first terminal A and the self-holding relay 2 and controlling a current for turning off the self-holding relay 2; 3, a capacitor 6 connected in series to the self-holding relay 2 and having its other end grounded; and a capacitor 6 connected to the first terminal A and having its other end connected to the control electrode of the first switching element 3. a second switching element 4 connected between the other end of the high resistance 7 and the ground and controlling a current for turning on the self-holding relay 2; and the relay 2. and the first switching element 3
and a diode 10 connected between the connection point of the high resistance 7 and the second switching element 4, and when the self-holding relay 2 is on, the first
a second terminal B to which a second voltage V2 that rises slower and falls faster than the voltage V1 is applied; one end is connected to the second terminal B, and the other end is connected to the first switching terminal B; The resistor 8 connected to the control electrode of the element 3, the power terminal P whose output is "L" (low level) when the power is turned on, and the output of the power terminal P set to "H".
a remote control control circuit 1 having a set terminal S for receiving a signal for switching to a high level (high level);
A drive circuit for a self-holding relay, which is connected to a control electrode of a switching element 4, and the set terminal S is connected to the resistor 8.