JPS63308620A - Power source control circuit - Google Patents

Abstract

PURPOSE:To dissolve the problem due to the consumption and deterioration of a contact part and a driving part and to execute the control with high reliability and a durability by using a solid state relay in place of a switch. CONSTITUTION:A solid state relay SSR4 functions as a non-contact relay element to be turned on at the time of impressing an input signal and be turned off at the time of no-impressing. At the time of operating, a switch 6 is shorted between b-c, then, the input side of an SSR4 is turned on and the output side is shorted. Thus, a commercial power source is supplied to the input side of a power source part 1 and an electric power is supplied to a load circuit 2. At such a time, an inverting OFF signal of a central processing part 3 is held at 'H'. Thereafter, a power source resetting is released and the load circuit 2 executes the usual action under the control of the processing part 3. Next, when the switch 6 is short-circuited between a-c, an inversion INT signal comes to be an 'L', interruption the processing part 3 is interrupted and a post- processing before the power source is turned off is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power supply control circuit that controls power off by a CPU.

[Conventional technology]

Conventionally, there are devices that require post-processing when the power is turned off.

For example, a computer may have a job being executed when the power is turned off, and it is necessary to complete the execution of that job, transfer data to be saved, and then turn off the power.

Additionally, if a call is in progress when the communication control device is powered off, the call is disconnected and necessary information is saved in a backed-up memory. It is necessary to ensure that other communication control devices can operate normally without being affected. Therefore, in order to reliably execute such post-processing when the power is turned off, a power switch to turn off the power and a button to execute post-processing are usually provided, and the operator turns on this button. After finishing the post-processing, a method is used in which a notification is received, such as by lighting a lamp or sounding a buzzer, and then the power switch is turned off.

However, with this method, there is a possibility that the operator may make a mistake in the procedure, so it cannot be said to be a foolproof method.

Therefore, in order to make the operation easier and prevent mistakes, there is a method in which the power switch also serves as a button for executing post-processing.

Figure 's2 is an example of the method.

1 is a power supply unit that converts commercial power (AC) to power supply (DC) used by ICs, LSIs, etc., 2 is a load circuit that is supplied with electricity from power supply unit 1, and 3 is a part of load circuit 2. It is a central processing unit. 8 is an electromagnetic relay that turns on the relay by passing a current through the coil, and 9 is a two-circuit interlocking manual switch (one switch is in the firing mode and the other is in the oven mode).

To explain the operation, first, when the power is turned on, manual switch 9, 6
By shorting the circuit (e-circuit oven),
The power supply unit 1 is supplied with commercial power and turns on, supplying electricity to the load circuit 2. As a result, the central processing unit 3 starts execution, causes current to flow through the coil of the electromagnetic relay 8, and one circuit is short-circuited.

After that, the routine moves to execution of the normal operation.

When the power is off, the 6 circuits of the manual switch 9 are connected to the oven (8
By shorting out the circuit, an interrupt is generated in the central processing unit 3. At this time, since the circuit C of the electromagnetic relay 8 is short-circuited, the power supply section remains on.

Due to this interruption, the central processing unit 3 executes post-processing before turning off the power, and after finishing the execution, cuts off the current to the coil of the electromagnetic relay 8, opens the circuit e, and turns off the power.

[Problem that the invention is trying to solve] However,
In the conventional example above, an electromagnetic relay and a manual switch are used as one power source.
Since this is the next side, several problems arise.

First, in the case of the primary side, safety standards are very strict, so you have to be very careful when selecting parts.Also, because the voltage is high, there are inrush currents, arc discharges, and sparks when the contacts of relays and switches open and close. Because electrical discharge occurs, durability is compromised due to deterioration due to wear and tear on the contacts.

In order to compensate for this drawback, a protection circuit must be provided externally to suppress the occurrence of the discharge.

Furthermore, since electromagnetic relays use coils to operate mechanical contacts, they consume a considerable amount of power and have problems with the durability of their moving parts.

[Means and effects for solving the problem] According to the present invention, the output side of the SSR is interposed on one side of the AC line of the power source that supplies power to the load circuit, and the Φ on the input side of the SSR is
A sub-power supply that constantly supplies the power required to drive the SSR is connected to the terminal, and a drive circuit (oven collector IC or equivalent function) controlled by the central processing unit is connected to the e terminal of the input terminal of the SSR. connect the output terminal of the transistor) and one connection terminal of a single-pole double-throw switch having a mechanical contact, and the other connection terminal of the switch is pulled up and connected to an interrupt to the CPU; With a configuration in which the common connection terminal of the switch is grounded, the SSR can be closed by closing the switch to the one connection terminal side.
means for turning on the power supply and supplying power to the load circuit, means for turning on the drive circuit by supplying power to the load circuit, and then connecting the switch to the other connection terminal. When the device is closed to the side, an interrupt is generated to the CPU, and when the CPU turns off the drive circuit, the SSR is turned off and the power supply is turned off, and power is no longer supplied to the load circuit. It is possible to provide a highly flexible power supply control circuit.

(Example) FIG. 1 shows an example of the present invention. In the figure, 1 is a power supply unit that converts a commercial power supply (AC) into a power supply (DC) that can be used by ICs, LSIs, etc., 2 is a load circuit that receives power from the power supply unit 1, and 3 is a load circuit 2. 4 is a SSR (solid state relay), 5 is a sub power supply that supplies power to the input side of 5SR4, 6 is used to notify the central processing unit 3 when the power is on and when the power is off. 7 is an oven collector IC used to turn off 5SR4 in response to a command from the central processing unit 3.

5SR4 is a non-contact relay element that remains on while an input signal is applied and turns off when the human input signal is removed, and has exactly the same function as a conventional electromagnetic relay. Its characteristics are that it can be driven directly by a microcomputer or IC, and has high reliability as there are no contacts or drive systems.

FIG. 3 is an internal configuration diagram of the SSR.

Numeral 10 is a phototransistor that converts electricity to light, and 11 is an element that converts light to electricity. Examples of couplers include transistors, thyristors, triacs, and the like.

12 is an ignition circuit for turning on and off the triac 13;

FIG. 4 is a timing chart of SSR.

When the SSR input voltage is turned on, the triac 13 is turned on, shorting occurs between the SSR outputs, and the voltage becomes 0 (■). Also, when the SSR input voltage is turned off, the triac 1
3 is turned off and the SSR output is opened.

Furthermore, as shown in FIG. 5, there is a zero voltage switch type SSR.

10 is a light emitting circuit, 11 is a light receiving circuit, 13 is a triac, and 14 is controlled so that it is always turned on near the zero voltage of the AC power supply and turned off when the load current is near zero, regardless of the phase of the applied input signal. This is a non-zero voltage point spark control circuit. FIG. 6 is a time chart.

This zero-voltage switch type SSR suppresses inrush current and transient voltage, and can suppress the adverse effects of noise.

FIG. 7 shows the operation timing of the present invention.

First, when switch 6 is shorted between b and c (oven between a and c), the input side of 5SR4 is turned on, and 5
The output side of SR4 is shorted.

This allows A to supply commercial power to the input side of the power supply section 1.
The C line is connected, power is supplied to the power supply section 1, and the power supply section 1 supplies power to the load circuit 2. At that time, the OFF signal of the central processing unit 3 is changed from 0FF to “H” by power reset.
" is determined and held. Thereafter, when the power supply reset is released, the load circuit 2 starts normal operation under the control of the central processing unit according to the program.

Also, since the oven is between a and 0 of the switch 6, the resistor R
By pulling up 1, the INT signal, which is the interrupt input signal of the central processing unit 3, is held at the "H" level.

Next, when switch 6 is shorted between a and C (opened between b and c), the INT signal transitions from "H" to "L",
The falling edge causes an interrupt to be sent to the central processing unit 3, and the central processing unit 3 receives the interrupt from the switch 6.
It recognizes that it is an NT signal interrupt and starts post-processing before turning off the power. Since the content of post-processing varies depending on the device, there are no limitations on the post-processing. As an example, we will discuss the case of a communication control device.

FIG. 8 shows the flow of various packets during the process in which a device connected to a packet switching network makes a call, transfers data, and disconnects the call.

In this case, when the power off request is notified from the switch 6 to the central processing unit 3 by the INT signal, if there is a call, the data transfer is completed and the call is disconnected, and finally the DISC command is sent and the VA response is received. There is a post-processing process that involves turning off the power. Furthermore, when a power off request is made, it is sufficient to immediately send a DISC command, receive a VA response, and then turn off the power.

FIG. 9 is a flowchart outlining a series of operations in the case of a communication control device using a token passing method in a local area network. In this example,
The flowchart in which the flow branches to "yes" when determining whether or not there is a power off request corresponds to post-processing.

In other words, when a power off request is received and a token is sent to you, all nodes participating in the network are notified by broadcast that your node will be disconnected from the network, and then the token is transferred to the next node. The post-processing process involves turning off the power.

In addition to that, there is also post-processing that writes data transfer history, error information, etc. to memory, which serves as a backup for the power supply. During such post-processing, even if the SSR becomes an oven between b and c of the switch 6, the OFF signal of the central processing unit 3 is held at "H" from power on as described above, so the oven collector IC7 can maintain L'' and 5SR4 can maintain an on state.

Thereafter, when the post-processing is completed, the central processing section moves to an operation of turning off the power, and changes the OFF signal from "H" to "L".

As a result, the oven collector 7 changes from L'' to 'H'', and since the b-c section of the switch 6 is also an oven, the input side of the 5SR4 is turned off, and the output section of the 5SR4 is ovend.

Therefore, the AC line is disconnected, power is no longer supplied to the power supply unit 1, and the load circuit is powered off.

Regarding the sub power supply, when the power is on, power must be constantly supplied to keep the light emitting circuit 10 of 5SR4 in the on state, but when the power is off, the circuit is cut off, so no current flows to the light emitting circuit 10, resulting in no consumption. There is no electricity.

Furthermore, as shown in FIG. 10, an embodiment using a backup power source 15 in place of the sub power source 5 of FIG. 1 will be described.

Conventionally, the sub power supply 5 is connected to IC, LS from a commercial power supply (AC).
Since it is necessary to generate the DC power necessary for I, etc., the circuit shown in FIG. 11 is used. 16 is a fuse, 1
7 is a power supply transformer that steps down the voltage and separates the circuit between the primary and secondary sides, and 18a, 18b, 18c, and 18d are diodes that rectify the AC power that has been stepped down by the transformer 17 and convert it into DC power. forming a bridge.

A capacitor 19 has the role of smoothing ripples in the DC power supply rectified by the diode bridge.

20 is a three-terminal regulator that can obtain any stable constant voltage without any external circuit.

21 is a capacitor for stably supplying the voltage output from the three-terminal regulator to the load circuit.

In Figure 1, while the SSR is kept in the on state,
Power is always supplied from this sub power supply.

In this way, the cost of the sub-power supply 5 increases significantly, and since there is a connection on the primary side, there are constraints such as safety standards, so it is necessary to design and manufacture the sub-power supply so that it satisfies all of the conditions. It must be made.

Therefore, as shown in FIG. 10, a backup power supply 15 was provided in the load circuit 2 to supply power to the 5SR4.

The internal configuration of the backup circuit 15 is shown in FIG.

Reference numeral 22 denotes a primary battery, and the types include an alkaline dry battery, a manganese dry battery, a mercury battery, a silver oxide battery, and a lithium battery.

R6 is a protective resistor that suppresses the generation of large current due to a short circuit in the circuit supplied by the primary battery 22. 23 is a diode, whose role is to supply power from the battery 22 to the vBB side;
Its role is to prevent current from flowing backwards from vBB to the battery 22. 24 is a diode, which is connected to the V to which the power supply section 1 is supplied.
The role of supplying CC power to the vBB side, and the role of V! Its role is to prevent current from flowing backwards from the IB side to the VCC side. To explain the operation, first, when the power is turned on, the battery 22 to 5SR4
By shorting switches 6b and 6c, 5SR4 is turned on, and power supply section 1
is turned on, and the Vcc'E source is supplied to the load circuit 2. When VCC becomes higher than the voltage generated by the battery 22, the power supply to the 5SR4 switches from the battery 22 to the VCC power supply, and thereafter continues to be supplied from the VCC power supply until the power is turned off.

From the above, the backup circuit in FIG. 12 is as shown in FIG.
Although it is a simpler and cheaper circuit than that of , it can perform the same function in terms of operation.

Furthermore, the battery 22 is consumed only during the first startup until the power supply section 1 is turned on, and after that, the VCC from the power supply section 1 is consumed.
5SR4 is turned on and the power supply section 1 is kept on by itself, so battery consumption is very small. Therefore, although this method requires maintenance such as battery replacement, it is possible to extend the replacement period for a considerably long period of time.

Next, FIG. 13 shows an example in which the battery is a secondary battery (that is, a rechargeable battery).

25 is a secondary battery, and the types include sealed nickel-cadmium storage batteries, cadmium batteries), and lead-acid batteries.

R7 is a bypass resistor for charging the battery 25.

23 is a diode that has the role of supplying power from the battery 25 to the v0 side and the role of preventing current from directly flowing back to the battery 25 from the vCCr V am side.

24 is a diode with V supplied from the power supply section 1 to the side.
The role of supplying CC power and the battery 2 through resistor R7
It has the role of supplying power to and charging the battery.

To explain the operation, as in FIG. 12, when the power is turned on, power is supplied from the battery 25 to 5SR4, and the switch 6 is turned on.
By short-circuiting between b and c of The power supply to is switched from the battery 25 to the Vcc power supply, and thereafter, the power is supplied from the VCC power supply until the power is turned off. At the same time, the battery 25 is charged by supplying power from the power supply VCC to the battery 25 via the resistor R7. Therefore, in the primary battery shown in FIG. 12, maintenance such as replacing the battery was required, but by using the secondary battery as shown in FIG. 13, there is no need to replace the battery.

Furthermore, in the case of Figure 13, the secondary battery is charged for a long time with a constant voltage source called VCC, so the charging current decreases as charging progresses, but even if the current is low, charging for a long time will result in overcharging. The drawback was that it shortened the battery life.

Therefore, FIG. 14 shows an embodiment in which a circuit is provided to prevent this overcharging. Reference numeral 26 denotes a voltage detection IC, which has the function of setting the OUT terminal to the "L" level when the voltage at the IN terminal exceeds a set value, and to the ``H'' level when the voltage at the IN terminal exceeds the set value.

Tri and Tr2 are transistors.

Next is an explanation of the operation, when the power is turned on/off.
Since it is similar to FIG. 13, it will be omitted and only the overcharge prevention circuit will be explained.

First, when the voltage of the battery 25 is lower than the voltage set in the voltage detection IC 26, the IN terminal detects this and sets the OUT terminal to "H" level. As a result, Tr2 is turned on, Tri is also turned on, and the power supply VCC is turned on.
and supplies power to the battery 25 through the diode 27,
Charge.

Next, due to charging, the voltage of the battery 25 changes to the voltage detection IC 26.
When the voltage becomes higher than the set voltage, the IN terminal detects it and sets the OUT terminal to "L" level, thereby turning Tr2 off and Tri also turning off.
Charging from power supply ■cc stops.

From the above, the pack-up power supply shown in FIG. 14 can prevent the life of the secondary battery from being shortened due to overcharging.

(Effects of the Invention) As explained above, in the present invention, by using SSR in place of relays and switches, there is no need to worry about durability and reliability due to wear and deterioration of contact parts and drive parts.Furthermore,
Since the on/off switch of SSR is electrical, it is easy to control the switch on and off at zero voltage, but using such a zero voltage switch type SSR, it is difficult to take countermeasures with relays and switches. Inrush currents and transient voltages, which were thought to be harmful, could also be suppressed, and the effects of noise generated by them could also be significantly reduced. In addition, the single pole double throw switch is
Since this is a secondary power supply circuit, there are no strict constraints.

Furthermore, since the power is turned on by shorting one side of the single-pole, double-throw switch, there is no electrical circuit to back up and keep it in the on state. Also, while the switch is short-circuited, the power will not be turned off due to malfunction of the electric circuit. Furthermore, by using a backup power source using primary or secondary batteries instead of a sub power source, you can reduce costs without sacrificing functionality, making it cost-effective and reliable! , it is possible to easily provide a highly durable power supply control circuit.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a power supply control circuit according to an embodiment of the present invention, Fig. 2 is a block diagram of a conventional power supply control circuit, and Fig. 3 is a block diagram of a power supply control circuit according to an embodiment of the present invention.
Internal configuration diagram of R, Figure 4 is a timing waveform diagram of the SSR in Figure 3, Figure 5 is an internal configuration diagram of the zero voltage switch type SSR, Figure 6 is a timing waveform diagram of the SSR in Figure 5. 7 is a time chart of the power supply control circuit of the present invention, FIG. 8 is a communication procedure for data transfer in a packet switching network, and FIG. 9 is a series of token passing method sequences for a local area network. 10 is a block diagram of a power supply control circuit according to another embodiment of the present invention; FIG. 11 is an internal block diagram of a sub power supply; FIG. 12 is an internal block diagram of a backup power supply; 14 is an internal configuration diagram of a backup power source using a secondary battery, and FIG. 14 is an internal configuration diagram of a pair of control circuits for charging the secondary battery of the backup power source.

Claims (1)

[Claims] The power supply to the switching element that controls power on/off is a backup power supply composed of a primary battery or a secondary battery, and when the power is turned on, power is supplied to the switching element, and when the switching element is turned on, , when the power supply starts up, it switches from the battery to this power supply and supplies power to the switching element,
A power supply control circuit that maintains its state until the power is turned off.