JP2000353019A - Power source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power source device that a safe operation area of a switching element on the primary side and a switching element for controlling low voltage forward output is optimized by setting a overcurrent protection set value matched to a use temperature by detecting the use temperature of equipment. SOLUTION: Relating to a voltage resonance type power source device to generate low voltage and high voltage output by the same transducer 7, it is provided with a current detecting means 29 to detect current of the low voltage forward output, a voltage converting means 30 to convert the current detected by the current detecting means 29 into voltage, a temperature detecting means 61 to detect temperature, a reference voltage generating means 60 to generate reference voltage based on the temperature detecting means 61 and a comparing means 58 to compare the voltage converting means 30 with the reference voltage generating means 60. And a PWM operation is switched according to a result of the comparing means 58.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply used for electronic equipment and the like, and more particularly to a control circuit of the power supply.

[0002]

2. Description of the Related Art FIG. 6 is a circuit diagram of a conventional power supply device. Conventionally, in a power supply device that generates a low-voltage output and a high-voltage output by one transformer, as shown in FIG. 6, a PWM1 signal from a control circuit 52 is supplied to a drive circuit 6 via a transformer 8, and a switching transistor 5 is The switching operation is performed, and the energy required by the output load is supplied via the transformer 7. In a power supply circuit that generates a low-voltage output and a high-voltage output by one transformer, a voltage resonance type is adopted in the circuit configuration, so that a low-voltage flyback output is detected by the voltage detection circuit 17 and the PWM1 signal is controlled. The voltage is controlled to be constant.

Further, low-pressure forward output control is performed by PW
A PWM2 signal is generated while synchronizing with the M1 signal, the drive circuit 27 is operated, and the output voltage control switching transistor 24 is controlled based on the result of the detection circuit 28. The control of the high-voltage output voltage is performed by controlling the high-voltage output control transistor 14 based on the information of the detection circuit 18 based on the PWM3.
The signal is controlled and turned on and off via a drive circuit 54 to control the voltage to be constant.

In addition, a certain value is provided for overcurrent protection of the low-voltage forward output, and control is performed so that the protection is activated when the value is exceeded.

[0005]

However, in the above conventional example, the overcurrent protection set value of the low voltage forward output is set to a certain value. For this reason, the overcurrent protection set value is set to the maximum load at the time of low temperature startup, etc., and the set value is not necessarily optimized. Features include:
It was not enough. Further, since the overcurrent protection set value is large, the power element is given an unnecessarily large margin in consideration of safety in a high temperature state and safety in a steady state. For this reason, there is a problem in that the power supply device as a whole becomes larger due to an increase in the size of the primary-side switching element and the low-voltage forward output control switching element.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and detects a use temperature of a device and provides an overcurrent protection set value in accordance with the use temperature to thereby provide a primary side switching element and a low voltage forward output. An object of the present invention is to provide a power supply device that optimizes a safe operation area of a control switching element.

Furthermore, by providing overcurrent protection set values for the start-up and steady-state operation of the equipment drive system separately, the abnormal current flowing through the primary-side switching element and the low-voltage forward output control switching element can be minimized. It is another object of the present invention to provide a power supply device that optimizes a safe operation area of these switching elements.

[0008]

According to a first aspect of the present invention, there is provided a power supply apparatus for generating a low voltage and a high voltage using the same transformer. Current detection means for detecting an output current; voltage conversion means for converting the current detected by the current detection means into a voltage; temperature detection means for detecting a temperature; and a reference based on a detection value of the temperature detection means. Reference voltage generating means for generating a voltage, and comparing means for comparing the output voltage of the voltage converting means with the output voltage of the reference voltage generating means, and switching the PWM operation according to the result of the comparing means. Features.

According to a second aspect of the present invention, in the power supply device of the first aspect, the current detecting means detects the current by a current transformer.

According to a third aspect of the present invention, in the power supply device according to the first aspect, the current detecting means detects by a resistor.

According to a fourth aspect of the present invention, in the power supply device of the first aspect, the reference voltage generating means has a plurality of reference voltages.

According to a fifth aspect of the present invention, in the power supply device for transmitting energy via a transformer, a current detecting means for detecting an output current, and a voltage conversion means for converting the current detected by the current detecting means into a voltage. Means, a temperature detecting means for detecting a temperature, a reference voltage generating means for generating a reference voltage based on a detected value of the temperature detecting means, an output voltage of the voltage converting means and an output voltage of the reference voltage generating means. And comparing the switching operation according to the result of the comparing means.

A power supply according to a sixth aspect of the present invention is the power supply according to the fifth aspect, wherein the current detecting means detects by a current transformer.

According to a seventh aspect of the present invention, in the power supply device according to the fifth aspect, the current detecting means detects by a resistor.

According to an eighth aspect of the present invention, in the power supply device according to the fifth aspect, the reference voltage generating means has a plurality of reference voltages.

According to a ninth aspect of the present invention, there is provided a power supply apparatus of a voltage resonance type in which a low voltage and a high voltage output are generated by the same transformer, a current detection means for detecting a low voltage forward output current, and the current detection means. Voltage converting means for converting the obtained current into a voltage, signal detecting means for detecting an on / off signal, reference voltage generating means for generating a reference voltage based on a detection value of the signal detecting means, and the signal detecting means A time measuring means for measuring time based on the detected value of, and a comparing means for comparing an output voltage of the voltage converting means with an output voltage of the reference voltage generating means, and according to a result of the signal detecting means. Changing the generated value of the reference voltage generating means,
The generation value of the reference voltage generation unit is changed according to the result of the time measurement unit.

According to a tenth aspect of the present invention, there is provided a power supply device according to the ninth aspect.
The power supply device according to the above, wherein the current detecting means detects the current using a current transformer.

The power supply device according to claim 11 is the power supply device according to claim 9.
The power supply device according to the above, wherein the current detecting means detects by a resistance.

According to a twelfth aspect of the present invention, there is provided a power supply device according to the ninth aspect.
Wherein the reference voltage generation means has a plurality of reference voltages.

According to a thirteenth aspect of the present invention, in the power supply device for transmitting energy via a transformer, a current detecting means for detecting an output current, and a voltage converter for converting the current detected by the current detecting means into a voltage. Means, signal detection means for detecting an on / off signal, reference voltage generation means for generating a reference voltage based on the detection value of the signal detection means, and time measurement based on the detection value of the signal detection means A time measuring unit; and a comparing unit that compares an output voltage of the voltage converting unit with an output voltage of the reference voltage generating unit, and changes a generated value of the reference voltage generating unit according to a result of the signal detecting unit. In addition, a generation value of the reference voltage generation unit is changed according to a result of the time measurement unit.

According to a fourteenth aspect of the present invention, there is provided a power supply device according to the first aspect.
3. The power supply device according to item 3, wherein the current detection means detects the current using a current transformer.

A power supply according to claim 15 is the power supply according to claim 1.
3. The power supply device according to item 3, wherein the current detection means detects by a resistance.

A power supply according to claim 16 is the power supply according to claim 1.
3. The power supply device according to item 3, wherein the reference voltage generation means has a plurality of reference voltages.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a configuration diagram showing a first embodiment of a power supply device according to the present invention.
In FIG. 1, 1 is an AC power supply, 2 is a rectifier diode, 3
Is a smoothing capacitor, 4 is a resonance capacitor, 5 is a switching transistor, 6 is a switching transistor 5
A drive circuit for transmitting energy to a load;
8 is a drive transformer for the switching transistor 5, 9 is a transformer for supplying power to the control circuit 52, 1
Reference numerals 0, 11, and 12 are high-voltage capacitors, 13 is a current limiting resistor, 14 is a high-voltage control transistor as a switching element, 15 and 16 are double rectification high-voltage diodes, 18 is a high-voltage output voltage detection circuit, 19, 22, and 23. Is a rectifier diode, 20 and 26 are smoothing capacitors, 17 is a low-voltage flyback output voltage detection circuit, 24 is a forward output control switching transistor as a switching element, 25 is a choke coil, and 27 is a forward output control switching transistor 24. A drive circuit, 28 is a low voltage forward output detection circuit, 29 is a current transformer for current detection of the switching transistor 24 for low voltage forward output control, 30 is a voltage conversion resistor, 31 is a diode, 32 is a peak hold capacitor, and 47 is a rectifier. Diode, 48, 9 smoothing capacitor, 50 is a three-terminal regulator, 52 a control circuit, 58 a comparator, 61 is a negative resistance (thermistor).

The operation of the circuit will be described below.

When the AC voltage 1 is applied, VDD is supplied to the control circuit 52 via the transformer 9. V
When DD is supplied to the control circuit 52, a pulse voltage is supplied from the control circuit 52 to the drive circuit 6 of the switching transistor 5 via the transformer 8, and the switching transistor 5 performs a switching operation to transfer energy required for each load to the transformer. 7 to each load. The voltage supplied to the low-voltage flyback output, which is the main control voltage, is sent by the detection circuit 17 to the analog / digital converter A / D 53 via the PWM1IN port of the control circuit 52, and via the comparator 56 to the register 57. Is increased or decreased, and the PWM1 output is varied to control and control the switching operation of the switching transistor 5.

The voltage supplied to the low voltage forward output is
The PWM2IN of the control circuit 52 is detected by the detection circuit 28.
Sent to the A / D 53 via the port
, The value of the register 55 is increased / decreased and the PWM2 output is varied to control and control the switching operation of the switching transistor 24. The voltage supplied to the high voltage output is sent by the detection circuit 18 to the A / D 53 via the PWM3 IN port of the control circuit 52, and the comparator 54 increases or decreases the value of the register 55 through the comparator 54 to change the PWM.
The three outputs are varied to control and control the operation of the high voltage control transistor 14.

A feature of the present invention resides in the control method of the overcurrent protection circuit for the low-voltage forward output current. The set value of the overcurrent protection circuit is set at the maximum current value at the time of starting at a low temperature.
Therefore, even when the use environment temperature changes, the overcurrent detection value level remains constant, and in a high temperature environment, a large load is applied to the switching transistor 5 and the low-voltage forward output control switching transistor 24. In order to optimize the overcurrent detection level at the time of high temperature, a negative resistance 61 (thermistor) is used as an overcurrent detection level setting element, and the setting value is automatically changed to a set value according to the use environment temperature (circuit 62). ).

For example, if the detection level at 0 ° C. is 10 A, the setting is made so that the detection level is automatically changed to 8 A at 25 ° C. With this method, if overcurrent protection of the low-voltage forward output current is performed, the current flowing through the switching transistor 5 and the low-voltage forward output switching transistor 24 at the time of abnormality can be suppressed to the minimum necessary. It is not necessary to select the switching transistor 5 and the low-voltage forward output control switching transistor 24 in consideration of the current margin for the current detection level at the time of startup, and the switching transistors 5 and 24 can be downsized. Thus, high reliability, downsizing, and cost reduction of the power supply device can be realized.

As described above, in the overcurrent protection circuit according to the present invention, the detecting means for detecting the use environment temperature is provided for the overcurrent protection set value, and the detection level of the overcurrent is changed in accordance with the use environment temperature. Is controlled so that the overcurrent protection operates. To achieve this, a temperature detection element is used as a reference voltage generating element of the low-voltage forward output overcurrent protection circuit so that the set value automatically changes in accordance with the temperature. Control to perform current protection. This prevents excessive current from flowing into the primary-side switching element and the low-voltage forward output control switching element, and eliminates the need for unnecessary margins for the primary-side switching element and the low-voltage forward output control switching element. It has realized miniaturization, miniaturization, and cost reduction.

(Second Embodiment) FIG. 2 is a configuration diagram showing a power supply device according to a second embodiment of the present invention.
In FIG. 2, 1 is an AC power supply, 2 is a rectifier diode, 3
Is a smoothing capacitor, 4 is a resonance capacitor, 5 is a switching transistor, 6 is a switching transistor 5
A drive circuit for transmitting energy to a load;
8 is a drive transformer for the switching transistor 5, 9 is a transformer for supplying power to the control circuit 52, 1
Reference numerals 0, 11, and 12 are high-voltage capacitors, 13 is a current limiting resistor, 14 is a high-voltage control transistor, 15 and 16 are double rectification high-voltage diodes, 18 is a high-voltage output voltage detection circuit,
9, 22, and 23 are rectifying diodes, 20 and 26 are smoothing capacitors, 17 is a low-voltage flyback output voltage detection circuit, 24 is a forward output control switching transistor, 25 is a choke coil, and 27 is a forward output control switching transistor 24. , A low-voltage forward output detection circuit 28, a current detection resistor 30 of the low-voltage forward output control switching transistor 24, a voltage detector 58 detects a voltage drop due to the current of the resistor 30,
An operational amplifier that outputs a voltage corresponding to the detected amount, 47 is a rectifying diode, 48 and 49 are smoothing capacitors, 50 is a three-terminal regulator, 52 is a control circuit, and 61 is a negative resistor (thermistor).

The operation of the circuit will be described below.

When the AC voltage 1 is applied, VDD is supplied to the control circuit 52 via the transformer 9. V
When DD is supplied to the control circuit 52, a pulse voltage is supplied from the control circuit 52 to the drive circuit 6 of the switching transistor 5 via the transformer 8, and the switching transistor 5 performs a switching operation to transfer energy required for each load to the transformer. 7 to each load. The voltage supplied to the low-voltage flyback output, which is the main control voltage, is sent by the detection circuit 17 to the analog / digital converter A / D 53 via the PWM1IN port of the control circuit 52, and via the comparator 56 to the register 57. Is increased or decreased, and the PWM1 output is varied to control and control the switching operation of the switching transistor 5.

The voltage supplied to the low voltage forward output is
The PWM2IN of the control circuit 52 is detected by the detection circuit 28.
Sent to the A / D 53 via the port
, The value of the register 55 is increased / decreased and the PWM2 output is varied to control and control the switching operation of the switching transistor 24. The voltage supplied to the high voltage output is sent by the detection circuit 18 to the A / D 53 via the PWM3 IN port of the control circuit 52, and the comparator 54 increases or decreases the value of the register 55 through the comparator 54 to change the PWM.
The three outputs are varied to control and control the operation of the high voltage control transistor 14.

A feature of the present invention lies in the control method of the overcurrent protection circuit for the low-voltage forward output current. The set value of the overcurrent protection circuit is set at the maximum current value at the time of starting at a low temperature.
Therefore, even when the use environment temperature changes, the overcurrent detection value level remains constant, and in a high temperature environment, a large load is applied to the switching transistor 5 and the low-voltage forward output control switching transistor 24. In order to optimize the overcurrent detection level at the time of high temperature, a negative resistance 61 (thermistor) is used as an overcurrent detection level setting element, and the control circuit 52 sequentially monitors the value,
Control is performed so as to automatically change the set value according to the use environment temperature (circuit 63).

For example, if the detection level at 0 ° C. is 4.5 V and the set current at this time is 10 A,
At 25 ° C., the setting is made such that the detection level is 3.5 V and the set current is automatically changed to the detection level of 8 A. With this method, if overcurrent protection of the low-voltage forward output current is performed, the current flowing through the switching transistor 5 and the low-voltage forward output switching transistor 24 at the time of abnormality can be suppressed to the minimum necessary. It is not necessary to select the switching transistor 5 and the low-voltage forward output control switching transistor 24 in consideration of the current margin for the current detection level at the time of startup, and these switching transistors 5, 2
4 can be reduced in size. Thus, high reliability, downsizing, and cost reduction of the power supply device can be realized.

(Embodiment 3) FIG. 3 is a block diagram showing a third embodiment of the power supply unit according to the present invention. FIG.
In FIG. 7, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description of the operation will be omitted. In FIG. 3, reference numeral 66 denotes a voltage setting circuit, and 67 denotes a configuration of the overcurrent protection circuit of the present invention.

Next, the operation will be described with reference to the flowchart shown in FIG. FIG. 4 is a flowchart showing a control procedure of the power supply device shown in FIG.

A feature of the present invention resides in a method of controlling an overcurrent protection circuit for a low-voltage forward output current. Overcurrent protection circuit 6
The set value of 7 is set at the maximum current value at the time of low temperature startup or the like. For this reason, the detection level of the overcurrent protection detection value remains constant between the start of the drive system and the steady-state operation, although the required current amount is significantly different. A large load may be applied to the forward output control switching transistor 24. In order to optimize the overcurrent protection detection level at the time of startup and steady operation, a voltage setting circuit 66 is provided inside the control circuit 52 to monitor the drive system ON / OFF signal (step S1), and to turn the drive system ON. When the / OFF signal is detected,
The overcurrent protection detection point is set to the first set value (V1) (step S2), and a certain time (t1) (time until transition to the steady state) elapses after the detection of the drive system ON / OFF signal. Then (steps S3 and S4), control is performed to set the overcurrent protection detection point to the second set value (V0) (step S5).

For example, assuming that the inrush current / inrush current duration time at the time of startup is 10 A (4 V) / 100 ms and the current during steady operation is 6 A (3 V), the drive system is turned ON / OFF.
When the signal is detected, the overcurrent protection detection point is set to 11
A (4.5V) and set the overcurrent protection set point to 7A 110ms after detecting the drive system ON / OFF signal.
(2.5V). With this method, if overcurrent protection of the low-voltage forward output current is performed, the current flowing through the switching transistor 5 and the low-voltage forward output control switching transistor 24 at the time of abnormality can be suppressed to the minimum necessary. There is no need to select the switching transistor 5 and the low-voltage forward output control switching transistor 24 in consideration of the current margin for the current detection level at the time of low-temperature startup, and these switching transistors 5, 24
Can be reduced in size. This will increase the reliability of the power supply,
Small size and low cost can be realized.

(Embodiment 4) FIG. 5 is a block diagram showing a fourth embodiment of the power supply unit according to the present invention. FIG.
In FIG. 7, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description of the operation will be omitted. In FIG. 5, reference numeral 64 denotes a voltage setting circuit, and 65 denotes a configuration of an overcurrent protection circuit of the present invention.

A feature of the present invention resides in a control method of an overcurrent protection circuit for a low-voltage forward output current. The set value of the overcurrent protection circuit is set at the maximum current value at the time of starting at a low temperature or the like. For this reason, the overcurrent protection detection level remains constant even though the required current amount is greatly different between the start-up of the drive system and the steady-state operation, and the switching transistor 5 and the constant-pressure forward A large load may be applied to the output control switching transistor 24. In order to optimize the detection level of the overcurrent protection at the time of start-up and at the time of steady operation, a voltage setting circuit 64 is provided inside the control circuit 52 to monitor the drive system ON / OFF signal, and After the detection, the transistor 63 is turned off to set the overcurrent protection detection point to the first set value (V1), and a certain time (t1) after detecting the drive system ON / OFF signal (to a steady state). After the elapse of the transition time, control is performed so that the transistor 63 is turned on in order to set the overcurrent protection detection point to the second set value (V0).

For example, assuming that the inrush current / inrush current duration time at the time of startup is 10 A (4 V) / 100 ms and the current at the time of steady operation is 6 A (3 V), the drive system is turned ON / OFF.
When the signal is detected, the overcurrent protection detection point is set to 11
A (4.5V) and set the overcurrent protection set point to 7A 110ms after detecting the drive system ON / OFF signal.
(2.5V). With this method, if overcurrent protection of the low-voltage forward output current is performed, the current flowing through the switching transistor 5 and the low-voltage forward output control switching transistor 24 at the time of abnormality can be suppressed to the minimum necessary. There is no need to select the switching transistor 5 and the low-voltage forward output control switching transistor 24 in consideration of the current margin for the current detection level at the time of low-temperature startup, and these switching transistors 5, 24
Can be reduced in size. This will increase the reliability of the power supply,
Small size and low cost can be realized.

[0045]

As described above, according to the present invention,
By using a temperature detection element as the reference voltage generation element of the low-voltage forward output protection circuit, the set value automatically changes according to the temperature, and by controlling to perform overcurrent protection based on this set value In addition, unnecessary current does not flow into the primary-side switching element and the low-voltage forward output control switching element, and the primary-side switching element and the low-voltage forward output control switching element do not need more margin than necessary. , Miniaturization and cost reduction can be realized.

Further, a voltage setting circuit is provided in the control circuit to monitor the drive system ON / OFF signal and to control the drive system ON / OFF.
When a signal is detected, the overcurrent protection detection point is set to the first set value, and after a certain period of time (the time until transition to the steady state) has elapsed since the detection of the drive system ON / OFF signal, overcurrent protection is performed. By controlling the detection point to the second set value, an unnecessary current does not flow into the primary-side switching element and the low-voltage forward output control switching element, and the primary-side switching element and the low-voltage forward output control switching. This eliminates the need for unnecessary margins for the elements, and makes it possible to achieve high reliability, small size, and low cost of the power supply.

[Brief description of the drawings]

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

FIG. 2 is a configuration diagram showing a power supply device according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram illustrating a power supply device according to a third embodiment of the present invention.

4 is a flowchart showing a control procedure of the power supply device shown in FIG.

FIG. 5 is a configuration diagram showing a power supply device according to a fourth embodiment of the present invention.

FIG. 6 is a circuit diagram of a conventional power supply device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC power supply 2 Rectifier diode 3 Smoothing capacitor 4 Resonant capacitor 5 Switching transistor 6 Drive circuit 7, 8, 9 Transformer 10, 11, 12 High voltage capacitor 13 Current limiting resistor 14 High voltage control transistor 15, 16 High voltage rectifying diode Reference Signs List 18 High voltage output voltage detection circuit 19, 22, 23 Rectifier diode 20, 26 Smoothing capacitor 17 Low voltage flyback output voltage detection circuit 24 Forward output control switching transistor 25 Choke coil 27 Drive circuit 28 Low voltage forward output detection circuit 29 Current detection Current transformer 30 Voltage conversion resistor 31 Diode 32 Peak hold capacitor 33 Zener diode 34 Driver for turning off drive circuit 35 Current detection resistor 36 Voltage comparator 47 Rectifier Diode 48, 49 Smoothing capacitor 50 Three-terminal regulator 52 Control circuit 58 Comparator 61 Negative resistance (thermistor) 62, 63 Overcurrent protection circuit 64, 66 Voltage setting circuit

Continued on the front page F-term (reference) 5H430 BB01 BB09 BB11 BB20 CC06 CC07 EE02 FF01 FF07 FF13 GG17 HH03 JJ07 LA07 LA10 5H730 AS01 BB13 BB23 BB57 BB86 DD02 DD22 EE02 EE06 EE07 EE08 EE18 EE31 FF18 XXV XX38

Claims (16)

[Claims] 1. A voltage resonance type power supply device for generating a low voltage and a high voltage output by the same transformer, a current detecting means for detecting a current of a low voltage forward output, and converting the current detected by the current detecting means into a voltage. Voltage converting means, a temperature detecting means for detecting a temperature, a reference voltage generating means for generating a reference voltage based on a detected value of the temperature detecting means, an output voltage of the voltage converting means and the reference voltage generating means. A power supply device, comprising: comparing means for comparing an output voltage, and switching a PWM operation according to a result of the comparing means. 2. The power supply device according to claim 1, wherein said current detection means detects the current using a current transformer. 3. The power supply device according to claim 1, wherein said current detection means detects by a resistance. 4. The apparatus according to claim 1, wherein said reference voltage generating means has a plurality of reference voltages.
The power supply as described. 5. A power supply device for transmitting energy via a transformer, a current detecting means for detecting an output current, a voltage converting means for converting a current detected by the current detecting means into a voltage, and detecting a temperature. Temperature detecting means, reference voltage generating means for generating a reference voltage based on a detection value of the temperature detecting means, and comparing means for comparing an output voltage of the voltage converting means with an output voltage of the reference voltage generating means. And a switching device that switches a switching operation according to a result of the comparing unit. 6. The power supply device according to claim 5, wherein said current detecting means detects the current by a current transformer. 7. The power supply device according to claim 5, wherein said current detecting means detects by a resistance. 8. The apparatus according to claim 5, wherein said reference voltage generation means has a plurality of reference voltages.
The power supply as described. 9. A voltage resonance type power supply device for generating a low voltage and a high voltage output by the same transformer, a current detecting means for detecting a current of a low voltage forward output, and converting the current detected by the current detecting means into a voltage. Voltage conversion means, signal detection means for detecting an on / off signal, reference voltage generation means for generating a reference voltage based on the detection value of the signal detection means, and time based on the detection value of the signal detection means. A time measuring means for measuring; and a comparing means for comparing an output voltage of the voltage converting means with an output voltage of the reference voltage generating means, and a generated value of the reference voltage generating means according to a result of the signal detecting means. And changing the value generated by the reference voltage generating means according to the result of the time measuring means. Power supply. 10. The power supply device according to claim 9, wherein said current detecting means detects by a current transformer. 11. The power supply device according to claim 9, wherein said current detection means detects by a resistance. 12. The power supply device according to claim 9, wherein said reference voltage generation means has a plurality of reference voltages. 13. A power supply device for transmitting energy via a transformer, a current detecting means for detecting an output current, a voltage converting means for converting a current detected by the current detecting means into a voltage, an on / off signal Signal detecting means for detecting a voltage; a reference voltage generating means for generating a reference voltage based on a detected value of the signal detecting means; a time measuring means for measuring time based on a detected value of the signal detecting means; A comparison unit that compares an output voltage of the conversion unit with an output voltage of the reference voltage generation unit, and changes a generation value of the reference voltage generation unit according to a result of the signal detection unit; A power supply device, wherein a value generated by the reference voltage generating means is changed according to a result. 14. The power supply device according to claim 13, wherein said current detection means detects by a current transformer. 15. The power supply device according to claim 13, wherein said current detection means detects by a resistance. 16. The power supply device according to claim 13, wherein said reference voltage generation means has a plurality of reference voltages.