JP2002010641A - Power unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cut down the cost of a power unit by use of a low-ranked element avoiding a trouble of a discharge-circuit element or a trouble of a rear-step circuit by eliminating a repeat of a power-on/off motion against a comparatively slow level change of an indication signal. SOLUTION: The number of changes of the indication signals (commercial- power signal, main-power on/off signal and remote-control signal) that change to a 'H' level is counted (step 101) and, if the number of the changes is not less than 10 times per minute (YES of step 102), a power-off signal is forcibly output and a power-off state is protected (step 103).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a power supply device for generating a plurality of DC power supplies from an AC power supply and supplying the generated DC power supplies to a subsequent circuit.

[0002]

2. Description of the Related Art Conventionally, in this type of power supply device, a plurality of DC power supplies are generated from a commercial power supply and supplied to a subsequent circuit. For example, two DC power supplies (first and second DC power supplies) are generated from an AC power supply of 50 Hz, and supplied to a subsequent circuit. In this case, the generation and stop of the first and second DC power supplies are performed by power-on / power-off.
The microcomputer receives the instruction signal for instructing power-off, and performs the operation.

The microcomputer outputs a power-on command to the sequence circuit when the instruction signal becomes "H" level. When the power-on command is input, the sequence circuit starts generation of the first DC power supply, checks output of the first DC power supply, and starts generation of the second DC power supply.

The microcomputer outputs a power-off command to the sequence circuit when the instruction signal goes to "L" level. When the power-off command is input, the sequence circuit stops generating the second DC power supply, and confirms that the second DC power supply is no longer output.
Generation of the DC power supply is stopped.

[0005] The output line of the second DC power supply is connected to a discharge circuit composed of, for example, a resistor and a transistor. The sequence circuit stops the generation of the second DC power supply and activates the discharge circuit to discharge the accumulated charge on the output line of the second DC power supply in order to ensure the sequence operation at the time of power-off. .

[0006]

In this power supply device, there is a possibility that the instruction signal repeats the "H" / "L" level at a high speed due to noise or the like, and a chattering phenomenon may occur. Therefore, in the conventional power supply device, for example, 100 mse
The level of the instruction signal within 100 msec is checked every c. If the 100 msec period that is not fixed to the “H” level or “L” level continues, the “H”
The occurrence of the chattering phenomenon is suppressed by ignoring the change in / L level.

FIG. 8 shows an example of the instruction signal in this case.
The “H” / “L” level is repeated in the periods T3 and T4. In this case, since the period not fixed to the “H” level or the “L” level is continuous with T3 and T4, the change of the “H” / “L” level in the periods T3 and T4 is ignored. On the other hand, in the periods T5 and T6, the period T5
5, the state is not fixed at the “H” level or the “L” level. However, in the period T6, the state is fixed at the “L” level.
A change from the level to the “L” level is regarded as a level change of the instruction signal.

As described above, in the conventional power supply device, it is possible to suppress the occurrence of chattering when the instruction signal changes at a high speed due to noise or the like. However,
The power-on / power-off is repeated for a relatively slowly changing level of the instruction signal such that the period not fixed at the “H” level or the “L” level is not continuous, and the discharge circuit operates in synchronization. . A circuit having an element configuration such as a resistor and a transistor as a discharge circuit consumes power every time the discharge circuit is turned on. For this reason, when the temperature of the element increases and the number of times of on / off increases, the element may be broken. In addition, there is a concern that a subsequent circuit that requires a sequence may also fail. For this reason, high-rank resistors and transistors are used, resulting in an increase in cost.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and an object of the present invention is to provide a power-on / power-off circuit for a relatively slowly changing level of an instruction signal.
An object of the present invention is to provide a power supply device that does not repeat power-off, eliminates a failure in a discharge circuit element and a circuit in a subsequent stage, and can reduce costs by using an element with a low rank.

[0010]

In order to achieve such an object, a first invention (an invention according to claim 1) counts the number of changes in the level of an instruction signal, and the number of changes is determined within a predetermined time. When the value is equal to or more than a predetermined value, a power-off command is forcibly output, and the generation stop state of the first and second DC power supplies stopped by the power-off command is protected. According to the present invention, for example, the number of times the instruction signal changes to the “H” level is 1
When the number of times reaches 10 or more per minute, a power-off command is forcibly output. Thus, if the power is on, the first
And the generation of the second DC power supply is stopped, and this generation stopped state is protected.

The second invention (the invention according to claim 2) is the first invention.
In the present invention, when the number of level changes within the predetermined time of the instruction signal is less than the predetermined value, the power-off command is forcibly issued when the number of level changes within the predetermined time falls within the predetermined range for a predetermined number of times. This is to output. According to the present invention, for example, when the number of changes to the "H" level in one minute of the instruction signal is less than ten, 1
The power-off command is forcibly output when the number of changes to the “H” level per minute is 1 to 9 times for three consecutive times (1 minute × 3 = 3 minutes).

A third invention (an invention according to claim 3) counts the number of times the level of the instruction signal changes, and if the number of changes exceeds a predetermined value within a predetermined time, sets the predetermined time to N (N
≧ 2) When the level change of the instruction signal in each divided time range is limited to one time, the number of times the level of the restricted instruction signal is changed is counted, and the number of changes becomes equal to or more than a specified value within a predetermined time. , Forcibly outputting a power-off command. According to the present invention, for example, if the number of times the instruction signal changes to the “H” level becomes 10 or more per minute, the instruction signal in each time range obtained by dividing one minute into three (1 minute ÷ 3 = 20 seconds) Changes to "H" level by 1
The number of changes to the "H" level of the limited instruction signal is counted, and when the number of changes becomes two or more per minute, a power-off command is output.

The fourth invention (the invention according to claim 4) is the third invention.
In the present invention, if the number of level changes within a predetermined time of the instruction signal is less than a predetermined value, if the state in which the number of level changes within a predetermined time falls within a predetermined range continues for a predetermined number of times,
The change of the level of the instruction signal in each time range obtained by dividing the predetermined time into N is limited to one time. According to the present invention, for example, when the number of changes to the "H" level for one minute is less than ten times in one minute, the state in which the number of changes to the "H" level for one minute is one to nine is included. When three consecutive times (1 minute x 3 = 3 minutes), 1 minute is divided into 3
The change of the instruction signal to the “H” level in each time range of minutes (= 3 seconds = 20 seconds) is limited to one time.

The fifth invention (the invention according to claim 5) is the third invention.
In the invention and the fourth invention, when the number of level changes within a predetermined time of the restricted instruction signal is less than a specified value, if the number of changes is 0, the level of the instruction signal in each time range obtained by dividing the predetermined time by N Remove the restriction of the change of 0
The power-off command is forcibly output when the state below the specified value is not repeated for a predetermined number of times. According to the present invention, for example, when the number of level changes to the "H" level for one minute of the restricted instruction signal is less than two times, if the number of changes is zero, one minute is divided into three times. The restriction of the change in the level of the instruction signal in the range is released, and if less than 0 times the state of less than 2 times continues for 2 times, the power-off command is forcibly output.

The above specific numerical values are merely examples, and it is needless to say that the present invention is not limited to these numerical values. Further, the level change of the instruction signal may be a change to the “L” level.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments. FIG. 1 is a circuit configuration diagram of a power supply device showing an embodiment of the present invention. In the figure, 1 is a commercial power supply (50 Hz AC power supply), 2 is an AC relay, and 3 is 1
Secondary rectifier circuit, 4 is a first switching power supply circuit, 5 is a second switching power supply circuit, 6 is a sequence circuit, 7
Is a microcomputer, 8 is a commercial power detection circuit, 9,
10 is a signal transmission circuit, 11 is a main power switch, and 12 is a remote control light receiving unit.

Reference numeral 13 denotes a first output monitoring circuit for monitoring the output status of the DC power supply (first DC power supply) from the switching power supply circuit 4 to a subsequent circuit, and 14 denotes a DC power supply (first power supply) from the switching power supply circuit 5. 2, a second output monitoring circuit for monitoring the output status of the DC power supply, 15 is a signal transmission circuit for transmitting a monitoring signal from the output monitoring circuit 13 to the sequence circuit 6, and 16 is a signal transmission circuit for outputting a monitoring signal from the output monitoring circuit 14. A signal transmission circuit for transmitting to the sequence circuit 6, a discharge circuit 17 connected to the output line L of the second DC power supply from the switching power supply circuit 5, and a transmission control signal 18 for transmitting the discharge control signal from the sequence circuit 6 to the discharge circuit 17. Signal transmission circuit.

The switching power supply circuit 4 includes a converter transformer 4-1, a transistor 4-2, a switching control circuit 4-3, a secondary rectifier circuit 4-4, an error detection circuit 4-5, and an error detection circuit. A signal transmission circuit 4- for transmitting an error signal from the circuit 4-5 to the switching control circuit 4-3;
6 is comprised. The error detection circuit 4-5 detects an error (a difference between an output voltage and a set voltage) of the first DC power supply output from the switching power supply circuit 4. The switching control circuit 4-3 receives the error signal from the error detection circuit 4-5 via the signal transmission circuit 4-6, and controls the on / off of the transistor 4-2 so that the error becomes zero.

The switching power supply circuit 5 includes a converter transformer 5-1, a transistor 5-2, a switching control circuit 5-3, a secondary rectifier circuit 5-4, an error detection circuit 5-5, and an error detection circuit. A signal transmission circuit 5-for transmitting an error signal from the circuit 5-5 to the switching control circuit 5-3.
6 is comprised. The error detection circuit 5-5 detects an error (difference between an output voltage and a set voltage) of the second DC power supply output from the switching power supply circuit 5. The switching control circuit 5-3 receives the error signal from the error detection circuit 5-5 via the signal transmission circuit 5-6, and controls the on / off of the transistor 5-2 so that the error becomes zero.

The discharge circuit 17 comprises a discharge resistor 17-1 and a transistor 17-2.
One end of -1 is connected to the output line L of the second DC power supply. The other end of the discharge resistor 17-1 is connected to the transistor 17-
2 and the emitter of the transistor 17-2 is grounded. The discharge control signal from the sequence circuit 6 via the signal transmission circuit 18 is applied to the base of the transistor 17-2.

[Basic Operation] The basic operation of the power supply device will be described with reference to a time chart shown in FIG. 2A shows the on / off state of the commercial power supply 1, FIG. 2B shows a commercial power detection signal a (AC POWER) to the microcomputer 7 via the signal transmission circuit 9 from the commercial power supply detection circuit 8, and FIG. c) Main power switch 1
1 is a main power on / off signal b (MAIN POWER) to the microcomputer 7 via the remote controller 1 or a remote control signal c (REM POWER) to the microcomputer 7 via the remote control light receiving section 12; A first DC power supply on / off signal e (POWER1) to the switching power supply circuit 4 of (1), (e) is a second DC power supply on / off signal f () from the sequence circuit 6 to the second switching power supply circuit 5 POWER2),
(F) is a discharge control signal i (D-CHARG) from the sequence circuit 6 to the discharge circuit 17 via the signal transmission circuit 18.
E).

[Power-On] In this example, the commercial power supply 1 has already been turned on, and this on-state is detected by the commercial power supply detection circuit 8 and the microcomputer 7 outputs a "H" level commercial power supply detection signal a. Is given.
When the microcomputer 7 receives the “H” level commercial power detection signal a, the main power on / off signal b from the main power switch 11 or the remote control light receiving unit 12
When the remote control signal c from the H level becomes "H" level (see FIG. 2).
(Point t1 shown in (c)), that is, when the instruction signal for instructing power on / power off becomes “H” level, the power on / off signal d (POWER) to the sequence circuit 6 is made “H” level.

Upon receiving an "H" level power on / off signal d from the microcomputer 7, the sequence circuit 6
Sets the AC relay on / off signal j to the “H” level to the AC relay 2 and turns on the contact 2-1 of the AC relay 2. As a result, the commercial power supply 1 is supplied to the primary rectifier circuit 3, and the rectified primary power is transmitted to the first switching power supply circuit 4 and the second switching power supply circuit 5. Next, the sequence circuit 6 sets the first DC power supply on / off signal e to the first switching power supply circuit 4 to the “H” level (point t2 shown in FIG. 2D). Thereby, the switching control circuit 4-3 in the switching power supply circuit 5 operates, and the generation of the first DC power supply is started.

When the first DC power is output from the first switching circuit 4, the monitoring signal g (WATCH1) from the output monitoring circuit 13 to the sequence circuit 6 becomes "H" level. In response to this "H" level monitoring signal g, the sequence circuit 6 sets the second DC power supply on / off signal f to the second switching power supply circuit 5 to the "H" level (FIG. 2 (e)). T3 point). Thereby, the switching control circuit 5- in the second switching power supply circuit 5
3 is activated, and the generation of the second DC power supply is started.

[Power off] Microcomputer 7
Means that when the "H" level commercial power detection signal a is given, the main power on / off signal b from the main power switch 11 or the remote control signal c from the remote control light receiving unit 12 becomes "L" level ( When the instruction signal for instructing power-on / power-off becomes “L” level, the power on / off signal d to the sequence circuit 6 is set to “L” level (point t4 in FIG. 2C).

Upon receiving the "L" level power on / off signal d from the microcomputer 7, the sequence circuit 6
Sets the second DC power supply on / off signal f to the second switching power supply circuit 5 to the “L” level (point t5 shown in FIG. 2E). As a result, the operation of the switching control circuit 5-3 in the second switching power supply circuit 5 is interrupted, and the generation of the second DC power supply is stopped. Further, the sequence circuit 6 raises the discharge control signal i to the discharge circuit 17 (point t4 shown in FIG.
-2 is turned on for a predetermined time. Thus, the accumulated charge on the output line L of the second DC power supply is discharged through the path from the discharge resistor 17-1 to the transistor 17-2.

When the generation of the second DC power supply is stopped and the accumulated charge on the output line L is discharged, the output monitoring circuit 14
From the monitor signal h (WATCH) to the sequence circuit 6
2) becomes the “L” level. In response to the "L" level monitor signal h, the sequence circuit 6 sets the first DC power supply on / off signal e to the first switching power supply circuit 4 to the "L" level (FIG. 2 (d)). T6 point shown). As a result, the operation of the switching control circuit 4-3 in the first switching power supply circuit 4 is interrupted, and the generation of the first DC power supply is stopped. Then, the sequence circuit 6
"L" for the AC relay on / off signal j to the AC relay 2
Level, and the contact 2-1 of the AC relay 2 is turned off.

[Basic Operation] The basic operation of the power supply device will be described with reference to a time chart shown in FIG. In this example, at time t0, the commercial power supply 1 is turned on. When the commercial power supply 1 is turned on, this on-state is detected by the commercial power supply detection circuit 8, and an “H” level commercial power supply detection signal a is supplied to the microcomputer 7 (point t1 shown in FIG. 3B). ). When the commercial power detection signal a becomes “H” level, that is, when the instruction signal for instructing power on / power off becomes “H” level, the microcomputer 7 turns on the main power switch 11 to turn on the main power on / off signal. b is set to the “H” level (point t2 shown in FIG. 3C), and the power on / off signal d to the sequence circuit 6 is set to the “H” level.

Upon receiving the "H" level power on / off signal d from the microcomputer 7, the sequence circuit 6
Sets the AC relay on / off signal j to the “H” level to the AC relay 2 and turns on the contact 2-1 of the AC relay 2. As a result, the commercial power supply 1 is supplied to the primary rectifier circuit 3, and the rectified primary power is transmitted to the first switching power supply circuit 4 and the second switching power supply circuit 5. Next, the sequence circuit 6 sets the first DC power supply on / off signal e to the first switching power supply circuit 4 to the “H” level (point t3 shown in FIG. 3D). Thereby, the switching control circuit 4-3 in the switching power supply circuit 5 operates, and the generation of the first DC power supply is started.

The first switching power supply circuit 4
Is output, the monitoring signal g from the output monitoring circuit 13 to the sequence circuit 6 becomes "H" level.
In response to the "H" level monitoring signal g, the sequence circuit 6 sets the second DC power supply on / off signal f to the second switching power supply circuit 5 to the "H" level (FIG. 3).
(Point t4 shown in (e)). Thereby, the switching control circuit 5-3 in the second switching power supply circuit 5 operates, and the generation of the second DC power supply is started.

[Power Off] Microcomputer 7
Means that the commercial power supply 1 is turned off (t5 shown in FIG.
When the commercial power detection signal a goes low (point t7 shown in FIG. 3B), that is, when the power-on / power-off command signal goes low, the main power switch 11 is turned off. When the power is turned off, the main power on / off signal b is set to the “L” level (point t8 shown in FIG. 3C), and the power on / off signal d to the sequence circuit 6 is set to the “L” level.

Upon receiving an "L" level power on / off signal d from the microcomputer 7, the sequence circuit 6
Sets the second DC power supply on / off signal f to the second switching power supply circuit 5 to the “L” level (point t9 in FIG. 3E). As a result, the operation of the switching control circuit 5-3 in the second switching power supply circuit 5 is interrupted, and the generation of the second DC power supply is stopped. Further, the sequence circuit 6 raises the discharge control signal i to the discharge circuit 17 (point t8 shown in FIG.
-2 is turned on for a predetermined time. Thus, the accumulated charge on the output line L of the second DC power supply is discharged through the path from the discharge resistor 17-1 to the transistor 17-2.

When the generation of the second DC power supply is stopped and the accumulated charge on the output line L is discharged, the output monitoring circuit 14
Monitoring signal h to sequence circuit 6 attains an "L" level. In response to the "L" level monitor signal h, the sequence circuit 6 sets the first DC power supply on / off signal e to the first switching power supply circuit 4 to the "L" level (FIG. 3 (d)). T11 point shown in the figure). Thereby, the switching control circuit 4 in the first switching power supply circuit 4
-3 is interrupted, and the generation of the first DC power supply is stopped. Then, the sequence circuit 6 sets the AC relay on / off signal j to the AC relay 2 to the “L” level,
The contact 2-1 of the relay 2 is turned off.

In the power supply device for performing such basic operations, in the present embodiment, a relatively slow instruction signal (commercial power supply signal a, main power on / off signal b, remote control signal With respect to the level change of c), repetition of power-on / power-off is prevented from occurring as follows. That is, the microcomputer 7 executes the processing operation as shown in the flowcharts of FIGS.

FIG. 7 is a block diagram showing a configuration of a main part of the microcomputer 7. In the figure, 7-1 is C
PU, 7-2 is ROM, 7-3 is RAM, 7-4, 7-
5 is an interface. CPU 7-1 is a ROM
4 and 5 are performed while accessing the RAM 7-3 according to the program stored in 7-2.

[Example of processing operation: FIG. 4]
Instruction signals provided via the interfaces 7-4 and 7-5, that is, the commercial power signal a, the main power on / off signal b, and the remote control signal c are monitored, and the number of changes to the "H" level is counted. (Step 101).
The number of times this instruction signal changes to the “H” level is 1 per minute.
If it is zero or more times (YES in step 102), the power on / off signal d to the sequence circuit 6 is forcibly set to "L".
Level (output power off command: Step 1)
03).

Thus, when the power is on (during generation of the first and second DC power supplies), the generation of the second DC power supply in the switching power supply circuit 5 is stopped, and the power supply of the second DC power supply is stopped. After the accumulated charge on the output line L is discharged via the discharge circuit 17, the generation of the first DC power supply in the switching power supply circuit 4 is stopped. CPU
7-1 protects this power-off state, that is, holds the power-off state, and then the instruction signal becomes "H".
Do not transition to the power-on state even if you rise to the level. At this time, the CPU 7-1 causes, for example, an LED (not shown) to emit light to notify the user of the protection state.

The protection in the power-off state is released when, for example, the main power switch 11 and another switch (for example, a reset switch) are simultaneously pressed. When the protection is released, the CPU 7-1 confirms the release state of the protection (YES in step 104), and then turns on the power to the sequence circuit 6 when the instruction signal goes to the “H” level. / Off signal d is set to the "H" level (power-on command is output: step 105).

The number of times the instruction signal has changed to "H" level is 1
If not more than 10 times per minute (N in step 102)
O), that is, the number of changes to the “H” level for one minute is 1
If less than 0, the CPU 7-1 continues counting the number of times the instruction signal has changed to the "H" level (step 106). That is, if the number of changes per minute is 1 to 9 consecutively for 3 minutes (YE in step 107)
S), proceed to step 103 and forcibly output a power-off command.

[Processing operation example: FIG. 5]
Instruction signals provided via the interfaces 7-4 and 7-5, that is, the commercial power signal a, the main power on / off signal b, and the remote control signal c are monitored, and the number of changes to the "H" level is counted. (Step 501).
The number of times this instruction signal changes to the “H” level is 1 per minute.
If it is zero or more (YES in step 502), the change in the level of the instruction signal in each time range obtained by dividing one minute into three is limited to one (step 503). That is, one minute is divided into three time ranges every 20 seconds, and the change of the instruction signal to the “H” level in each time range is two or more, but one.

Then, "H" of the restricted instruction signal
The number of changes to the level is counted, and if the number of changes is two or more per minute (YES in step 504), the power on / off signal d to the sequence circuit 6 is forcibly set to the "L" level. (Output a power-off command: Step 505).

Thus, when the power is on (while the first and second DC power supplies are being generated), the generation of the second DC power supply in the switching power supply circuit 5 is stopped, and the second DC power output line is turned off. After the accumulated charge on L is discharged through the discharge circuit 17, the generation of the first DC power supply in the switching power supply circuit 4 is stopped. CPU7-
1 protects the power-off state, that is, keeps the power-off state, so that the power-on state is not changed even if the instruction signal subsequently rises to the “H” level. At this time, the CPU 7-1 causes, for example, an LED (not shown) to emit light to notify the user of the protection state.

The protection in the power-off state is released when, for example, the main power switch 11 and another switch (for example, a reset switch) are simultaneously pressed. When the protection is released, the CPU 7-1 confirms the release state of the protection (YES in step 506), and then turns on the power to the sequence circuit 6 when the instruction signal goes to the “H” level. / Off signal d is set to "H" level (power-on command is output: step 507).

The number of times the instruction signal has changed to "H" level is 1
If not more than 10 times per minute (N in step 502)
O), that is, the number of changes to the “H” level for one minute is 1
If less than 0, the CPU 7-1 continues counting the number of times the instruction signal has changed to the “H” level (step 508), and the number of times of change per minute is 1 to 9 for 3 consecutive times. That is, if the number of changes per minute is 1 to 9 consecutively for 3 minutes (YE in step 509)
S), proceed to step 503 to limit the change in the level of the instruction signal to one in each time range obtained by dividing one minute into three.

When the number of times the restricted instruction signal changes to the "H" level is not twice or more per minute (step 504)
NO), that is, when the number of changes to the “H” level for one minute is less than two, if the number of changes is zero (YES in step 510), the CPU 7-1 changes the level of the instruction signal. After the restriction is released (step 511), the process returns to step 501.

In step 510, if the number of changes is not 0, that is, if the number of changes is 1, the process returns to step 503. In this case, the CPU 7-1
Indicates that the state in which the number of changes to the "H" level of the limited instruction signal is once per minute has been repeated twice (step 50).
(YES in Step 4), the process proceeds to Step 505, and a power-off command is forcibly output.

As described above, according to the present embodiment, the power-off command is forcibly output in response to the relatively slowly changing level of the instruction signal, and the power-off state is protected. The power-on / power-off is not repeated, and it is possible to eliminate the failure of the elements in the discharge circuit 17 and the circuits in the subsequent stages. Also,
It is possible to reduce the cost by using a low rank element as an element used in the discharge circuit 17.

In the above-described embodiment, the first DC power supply is generated by the first switching power supply circuit 4 and the second DC power supply is generated by the second switching power supply circuit 5.
However, the second DC power supply may be generated from the first DC power supply. For example, as shown in FIG. 6, a chopper circuit 19 is provided, a first DC power supply from the switching power supply circuit 4 is supplied to the chopper circuit 19, and a second DC power supply is generated from the first DC power supply by chopper control. You may make it.

In FIG. 6, when a power-on command is given from the microcomputer 7, the sequence circuit 6 sets the DC power supply on / off signal e to the switching power supply circuit 4 to “H” level, and sets the first DC power supply Start generation. When the first DC power supply is output from the switching power supply circuit 4, the monitoring signal g from the output monitoring circuit 13 to the sequence circuit 6 becomes "H" level. In response to the “H” level monitoring signal g, the sequence circuit 6 sets the chopper circuit on / off signal k via the signal transmission circuit 20 to the chopper circuit 19 to the “H” level. Thereby, chopper control in the chopper circuit 18 is started, and a second DC power supply is generated based on the first DC power supply from the switching power supply circuit 4.

In FIG. 6, when a power off command is given from the microcomputer 7, the sequence circuit 6 sets the chopper circuit on / off signal k to the chopper circuit 19 to "L" level. Thereby, the chopper circuit 1
9, the chopper control is interrupted, and the generation of the second DC power supply is stopped. Further, the sequence circuit 6 sets the discharge control signal i to the discharge circuit 17 to the “H” level, activates the discharge circuit 17, and discharges the accumulated charge on the output line L of the second DC power supply. Second in the chopper circuit 19
Is stopped, and the accumulated charge on the output line L is discharged, the monitoring signal h from the output monitoring circuit 14 to the sequence circuit 6 becomes “H” level. In response to the "H" level monitor signal h, the sequence circuit 6
Sets the DC power supply on / off signal e to the switching power supply circuit 4 to the “L” level to stop the generation of the first DC power supply.

In FIGS. 1 and 6, the microcomputer 7 is used as a command means for outputting a power-on / power-off command to the sequence circuit 6, but the same processing as that of the microcomputer 7 is performed by a hardware circuit. You may do so. In FIGS. 1 and 6, the switching power supply circuits 4 and 5 are known circuits and are not directly related to the present invention, so that detailed description of the configuration and operation is omitted. In FIGS. 1 and 6, two DC power supplies are generated. However, it goes without saying that the present invention can be similarly applied to a case where three or more DC power supplies are generated.

[0052]

As apparent from the above description, according to the present invention, a power-off command is forcibly output in response to a relatively slow change in the level of an instruction signal, and the power-off state is protected. Therefore, power-on / power-off is not repeated, failure of the discharge circuit element and the subsequent circuit is eliminated, and the cost can be reduced by using an element with a low rank.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a power supply device according to an embodiment of the present invention.

FIG. 2 is a time chart for explaining a basic operation of the power supply device.

FIG. 3 is a time chart for explaining a basic operation of the power supply device.

FIG. 4 is a flowchart illustrating a processing operation example of a microcomputer in the power supply device.

FIG. 5 is a flowchart illustrating an example of a processing operation of a microcomputer in the power supply device.

FIG. 6 is a circuit configuration diagram illustrating an example of a power supply device using a chopper circuit.

FIG. 7 is a block diagram showing a configuration of a main part of a microcomputer used in the power supply device shown in FIGS. 1 and 6;

FIG. 8 is a diagram illustrating an example of an instruction signal that repeats “H” / “L” levels at a high speed due to noise or the like;

[Explanation of symbols]

1 ... commercial power supply (50 Hz AC power supply) 2 ... AC relay,
3 Primary rectifier circuit, 4 first switching power supply circuit, 4-1 converter transformer, 4-2 transistor, 4-3 switching control circuit, 4-4 secondary rectifier circuit, 4- 5 Error detection circuit, 4-6 Signal transmission circuit, 5 Second switching power supply circuit, 5-1 Converter transformer, 5-2 Transistor, 5-3 Switching control circuit, 5-4 Secondary Side rectifier circuit, 5-5: Error detection circuit, 5-6: Signal transmission circuit, 6: Sequence circuit, 7: Microcomputer, 8: Commercial power supply detection circuit, 9, 10, 15, 16, 18, 20, 20: Signal Transmission circuit, 11: Main power switch, 12: Remote control light receiving unit, 1
3 ... first output monitoring circuit, 14 ... second output monitoring circuit,
17 ... discharge circuit, 17-1 ... discharge resistance, 17-2 ... transistor, 19 ... chopper circuit.

Claims (5)

[Claims] 1. A DC power supply generating means for rectifying an AC power supply to generate a first DC power supply and a second DC power supply; a discharging means connected to an output line of the second DC power supply; Instruction means for receiving an instruction signal for instructing power-off, outputting a power-on instruction when the instruction signal reaches a first level, and outputting a power-off instruction when the instruction signal reaches a second level. And a power-on / power-off command from the command means. If the power-on command is input, the first
After the generation of the DC power supply is started, the generation of the second DC power supply is started. When a power-off command is input, the generation of the second DC power supply is stopped and the second DC power supply is stopped. Sequence means for stopping the generation of the first DC power supply after discharging the accumulated charge on the output line of the DC power supply through the discharging means, wherein the command means comprises: The number of changes is counted, and when the number of changes becomes equal to or more than a predetermined value within a predetermined time, a forced power-off means for forcibly outputting a power-off command, and generation is stopped by a power-off command from the forced power-off means. And a protection unit for protecting the first and second DC power supplies from being stopped. 2. The power-off means according to claim 1, wherein the number of level changes within the predetermined time falls within a predetermined range when the number of level changes within the predetermined time of the instruction signal is less than a predetermined value. A power supply device for forcibly outputting a power-off command when a state continues for a predetermined number of times. 3. A DC power supply generating means for rectifying an AC power supply to generate a first DC power supply and a second DC power supply; a discharging means connected to an output line of the second DC power supply; Instruction means for receiving an instruction signal for instructing power-off, outputting a power-on instruction when the instruction signal reaches a first level, and outputting a power-off instruction when the instruction signal reaches a second level. And a power-on / power-off command from the command means. If the power-on command is input, the first
After the generation of the DC power supply is started, the generation of the second DC power supply is started. When a power-off command is input, the generation of the second DC power supply is stopped and the second DC power supply is stopped. Sequence means for stopping the generation of the first DC power supply after discharging the accumulated charge on the output line of the DC power supply through the discharging means, wherein the command means comprises: The number of changes is counted, and when the number of changes becomes equal to or more than a predetermined value within a predetermined time, a change in the level of the instruction signal in each time range obtained by dividing the predetermined time by N (N ≧ 2) is limited to one. Limiting means for counting the number of changes in the level of the instruction signal limited by the limiting means, and forcing a power-off command to output a power-off command if the number of changes exceeds a specified value within a predetermined time. When the power supply apparatus characterized by comprising a protection means for applying a protection to generation stop state of said first and second DC power supply powered off generated by a command is stopped from the forcible power-off means. 4. The apparatus according to claim 3, wherein the limiter sets a state in which the number of level changes within a predetermined time falls within a predetermined range when the number of level changes within the predetermined time is less than a predetermined value. A power supply device, wherein, when a predetermined number of consecutive times have occurred, a change in the level of the instruction signal in each time range obtained by dividing the predetermined time into N is limited to one time. 5. The method according to claim 3, wherein the forced power-off means sets the number of times of change of the instruction signal limited by the limiting means to zero when the number of level changes within a predetermined time is less than a prescribed value. Then, the restriction of the change of the level of the instruction signal in each time range obtained by dividing the predetermined time into N is released, and if it is not 0 times, the power is forcibly turned off when the state less than the specified value continues for a predetermined number of times. A power supply device for outputting a command.