JPH10117475A - Power supply unit by active filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate forming a power source by an active filter, which restrains generation of harmonic by using an inrush current preventing means and a control reference voltage generating means as the variable impedance of a transistor. SOLUTION: In an inrush current preventing device 20, when the voltage generated at a resistor R1 exceeds the saturated voltage between the base and emitter of a transistor Tr4, base current runs through R2, the Tr4 turns on to limit the base current of a Tr3 which runs through R3, the current which runs through Tr3 is made into a constant current for preventing excess current. A control reference voltage generating means 21 divides Vin with R6 and Tr6, and variable impedance consisting of R9, the divided voltage is impedance- converted by the Tr9, and is divided further by Rd7 and Rd8 to attain prescribed reference voltage Vm. This control is conducted by averaging the erroneous signal Ver of a comparator 14 with R8 and a capacitor C4, by which the reference voltage Vm stabilizes the average of output Vo to change a peak value with a roughly sinewave arc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a pulsating flow in which a current of an AC (commercial) power supply is controlled so as to flow in a substantially sinusoidal arc, and a harmonic component of an AC power supply frequency is suppressed to improve a power factor. The present invention relates to a configuration of a power supply device using an active filter that obtains a substantially stabilized DC output.

[0002]

2. Description of the Related Art A prior art will be described with reference to the drawings. FIG. 1 shows a schematic configuration of a capacitor input type switching type power supply device. 1 represents an AC (commercial) power supply, AC100 / 11
There are 7 volts and 230 volts AC. Reference numeral 2 denotes a rectifier for full-wave rectification, and reference numeral 3 denotes an inrush current prevention circuit for preventing an inrush overcurrent from flowing through the capacitor 4. Reference numeral 5 denotes a switching type converter, which switches a charging voltage of a capacitor by switching a transformer and normally emits a predetermined DC output insulated from a primary side and a secondary side. Vin represents the voltage waveform of full-wave rectification. For the inrush current prevention circuit, use a simple circuit that uses a thermistor with a small capacity power supply of about 50 watts or less, whose resistance is high when the power is turned on, and whose resistance decreases due to a temperature rise when power is supplied continuously. In the case of more than this, a complicated configuration in which a resistor of several tens of ohms and a thyristor are connected in parallel, and when the power supply circuit starts up, the thyristor conducts electricity and short-circuits the resistor.

FIG. 2A shows the charging voltage and current of the capacitor 4 when the power supply device of FIG. 1 has a load.
If the capacity of the capacitor 4 is large, the charging voltage has a small fluctuation and the conversion efficiency of the converter is good, but the conduction angle of the charging current is narrow and the peak is large.

[0004] In the era where switching power supplies are used in all electronic devices such as personal computers recently, a serious problem occurs. This causes a problem that a large amount of peak current is superimposed on the AC power supply line, thereby making it impossible to normally operate the electronic device due to the line drop, or causing interruption or failure of the power distribution equipment.

Therefore, as shown in FIG. 2B relating to the present invention, the output voltage waveform has a pulsating current of the AC power source, but the current is controlled to flow in a substantially sinusoidal arc, so that the power factor is close to 100%. Active filter systems have been proposed. In FIG. 1, the power factor is 50-60%.

FIG. 3 shows an outline of the proposed embodiment. Choke transformer 10 with transistor Tr
It is excited by 1 to accumulate energy, and is discharged to the output capacitor Co when Tr1 is turned off. The output voltage Vo is set higher than the peak voltage of Vin.

For example, since it is necessary to guarantee a fluctuation of ± 15% of the normal AC, the maximum peak is 190 volts in the AC100 / 117 system, and Vo is set to around 250 volts or more.

Reference numeral 11 denotes an auxiliary power supply for emitting the stabilized output Vs to supply necessary power to the circuit. When the rising circuit starts operating at Vin, power is supplied from the auxiliary coil of the choke transformer 10. Receiving from Vin is cut off.

Reference numeral 12 denotes a 30-200 kHz oscillator (OSC), which is an RS-FF.
(Reset / set flip-flop) and output Q
Turn Tr1 ON. When turned on, the choke transformer 10 outputs the current I = Ib + Vin / L · t (Ib: initial current,
L: transformer inductance, t: time) flows and accumulates electromagnetic energy. When Tr1 turns off, current Ie at the time of OFF
Then, the current I = Ie− (Vo−Vin) / L · t flows to the capacitor Co via the backflow prevention diode D1. When this is viewed from the Vin side, the current is controlled so as to continuously flow in a substantially sinusoidal arc, and a pulsating flow but a substantially stabilized output Vo is obtained. In this case, at the same output power, the peak current is at least a quarter of that in FIG. 1, and the above-mentioned problem is solved.

[0010] However, the harmonics of the AC are almost only the fundamental wave in the AC line, and there is no problem, but the high frequency of the OSC 12 can be easily carried. Therefore, it is necessary to strengthen a filter (not shown).

Now, a method for realizing this will be described. A divided voltage Vd is generated from the output Vo using the voltage dividing resistors Rd3 and Rd4, and Vd
Is set to an average voltage of the half cycle of AC by the capacitor C1. The comparator 14 compares Vd with the reference voltage Vr to generate an error signal Ver. On the other hand, Vin obtains a predetermined divided voltage Vir by the voltage dividing resistors Vd1 and Vd2. This Vir and Ver are multiplied by a multiplier 15, and a multiplied output voltage Vm indicated by a dotted line in FIG. 4B is compared with Vs1 generated in a resistor Rs1 proportional to a current flowing through Tr1 by a comparator 1.
Compare with 6. When Vs1> Vm, the comparator 16 resets RS-FF, and Tr1 turns off. FIG. 4 schematically shows these relations. (A) shows the oscillation pulse of the OSC12, (b) shows the current flowing through Tr1 and the multiplied output Vm, and (c) shows the continuous current of Vin substantially in the form of a sine arc. Are respectively shown. However, when the load is light or when the load fluctuates greatly, the load may be intermittent or may be far away from the sine arc. In any case, on average, Vin
Current flows in a sinusoidal arc and has a power factor of 100 with less AC harmonics.
FIG. Also, the conversion efficiency of the input power to output power ratio in this method can be 90% or more, although it depends on the load.

The active filter type power supply device shown in FIG. 3 has an advantage, but the output is a pulsating flow and the input side and the output side are not insulated. Therefore, the converter 5 of FIG. I have to do it.

As described above, the conventional embodiment has been briefly described with reference to FIG. 3. However, actually, the AC current is directly detected by the current transformer to calculate the input power and the output power. Has been reduced.

There is a great defect that the power supply device becomes expensive due to an increase in the mounting volume and the number of parts. Therefore,
At present, it is applied only to large power supplies of several kilowatts.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and an object of the present invention is to provide an active filter which improves a power factor and suppresses generation of harmonics. It is an object of the present invention to provide a power supply device using an active filter which has a simple configuration and is inexpensive, and which can be applied to an insulated power supply having a small capacity of several hundred watts or less at low cost.
Still another object is to provide a power supply device using an active filter in which an insulated converter is also inexpensive and the total cost is reduced.

[0016]

A power supply device according to claim 1 performs full-wave rectification on an AC (commercial) power supply through a filter with a rectifier having an output of Vin, and means for preventing inrush current from the Vin. A choke transformer having an auxiliary coil, a main transistor for exciting the choke transformer, a loop returning to the Vin, and an excitation capacitor for storing the excitation energy of the choke transformer via a diode from a connection point between the choke transformer and the main transistor. A storage loop,
A power supply device based on an active filter that obtains a boost DC output Vo composed of an auxiliary power supply that supplies power to a circuit that rises at the Vin and that is generated by an induced voltage of the auxiliary coil, wherein the inrush current prevention unit is preferably Is the main pole of the transistor whose control pole is driven by a constant current source.
A resistor is provided on the AC power supply side, and the control electrode of the transistor is controlled by a control transistor that detects the voltage generated at the resistor by the base-emitter saturation voltage to limit the maximum current of the choke transformer, and It is composed of a series-connected resistor and a diode that initially charges the output capacitor from the connection point of the resistor, and in addition to those that operate safely and simply, the average value of the output Vo for about half a cycle of the AC power supply or more. Output voltage detecting means, an error detecting means comprising a comparator for comparing the value of the output voltage detecting means with a reference voltage Vr, and modulating the voltage of Vin with a predetermined resistance and an error signal of the error detecting means. A control reference voltage generating means having a simple configuration for generating a reference voltage Vir by dividing the voltage with a variable impedance, and a transmitter for transmitting at a predetermined frequency for setting a storage means, When the voltage generated by the detection resistor for detecting the current of the transistor exceeds the reference voltage Vir, the comparator emits an output to reset the storage means, and a power amplifier for amplifying the output of the storage means. Driving means for driving and controlling the current so as to draw a sine arc when viewed from the AC power supply side, suppressing the harmonic components of the AC power supply frequency and improving the power factor. It is characterized in that it is possible to provide an inexpensive device having a simple configuration with a power supply device using an active filter for obtaining an output.

According to a second aspect of the present invention, in the power supply apparatus, another variable impedance controlled by a peak voltage holding means of the AC power supply is provided in parallel with the variable impedance in the configuration of the control reference voltage generating means. 2. The method according to claim 1, wherein a maximum of the voltage Vir is generated in inverse proportion to a peak voltage of the AC power supply.
A power supply device according to the active filter described in the above,
It is characterized by having control characteristics that are not significantly affected by the AC power supply voltage.

The power supply according to claim 3 is characterized in that the output Vo
Is an input, an insulated type half-bridge converter that insulates the primary and secondary sides is formed.On the secondary side, an intermediate capacitor is directly arranged by full-wave rectification, and the primary and secondary sides are A power supply device using an active filter to which a resonance current coupling is applied and a DC stabilized output is obtained by chopping the voltage of the intermediate capacitor, wherein a rush current preventer for the intermediate capacitor is removed. It is assumed that.

The power supply according to claim 4 is characterized in that the output Vo
Input, form an insulated half-bridge converter that insulates the primary and secondary sides.On the secondary side, connect to the output capacitor through full-wave rectification and switch means to pass the resonant current waveform. A power supply apparatus using an active filter to which a number is controlled by the switch means to obtain a stabilized DC output, wherein a control circuit on the secondary side is extremely simplified.

According to a fifth aspect of the present invention, in the power supply device, the chopping means of the chopping method according to the third and fourth aspects and the switch means are a P-type field-effect transistor, and all the components are used to drive the transistor. On the high voltage end side of the wave rectification, a voltage source and a complementary emitter follower supplied with power from the voltage source, a resistor disposed between the input terminal of the emitter follower and the high voltage terminal, and a predetermined resistance And a power supply device based on an active filter executed by a drive circuit driven by a constant current so as to generate the above voltage, wherein power consumption of the drive circuit is reduced by a simple circuit.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described. Note that constituent elements, means, and symbols having the same meaning as described above are given the same symbols and numbers.

FIG. 5 shows an embodiment of a power supply device using an active filter according to the present invention. Reference numeral 20 denotes an inrush current preventer when the power is turned on. A voltage that generates a current flowing through the transistor Tr3 in the resistor R1 is applied to the transistor Tr4.
Exceeding the base-emitter saturation voltage (varies depending on temperature, but approximately 0.6 volts) causes the base current to flow through R2, turning on Tr4 and limiting the base current of Tr3 that was flowing through resistor R3, The constant current of 0.6 / R1 is selected (a value that does not saturate the choke transformer 10) to prevent excessive current. The diode D3 and the resistor R4 are connected to the output capacitor Co through R1.
This is for charging from this loop when Co is not charged much. Compared to the conventional method described above, this type of inrush current protector has a feature that ensures sufficient safety. For example, even if the current is intentionally repeated, it responds according to the circuit state, so it is not destroyed. Having.

3 is different from the conventional embodiment shown in FIG. 3 in that a field effect transistor may be used, but a bipolar transistor Tr2 is used, and a control reference voltage generating means 21 corresponding to the multiplier 15 is provided. It is. Although it cannot be said generally in general, the capacitance charge-discharge loss is Cs · Vo ^ 2 · f (Cs: parasitic capacitance,
f: Oscillation frequency of OSC 12)

However, since switching loss due to storage delay increases, the Tr7 of the emitter follower and the resistor 1 are connected between the RS-FF and the RS-FF in order to strengthen the base drive.
0, a grounded transistor Tr8 for extracting the base current is provided.

The control reference voltage generating means 21 outputs the control reference voltage.
Vm is generated by a simple configuration.
6 and a variable impedance composed of a transistor Tr6 and a resistor R9, and these components are considerably high in order to suppress power consumption. The voltage is divided by Rd7 and Rd8 to obtain a predetermined control reference voltage Vm. The control of the variable impedance is executed by averaging the error signal Ver of the comparator 14 with the resistor R8 and the capacitor C4.

Then, the peak value of the control reference voltage Vm shown in FIG. 6 changes substantially in a sinusoidal arc so that the average value of the output Vo is stabilized. Naturally, the output Vo is an average value control,
As shown in FIG. 2B, the pulsating current is twice the commercial power frequency, but can be controlled to ± 10% or less of the average value.
FIG. 6 shows an example of operation at low, medium, and high AC voltages.
2, t3 indicates the ON time of Tr2, and t2, t4, t6 indicate the OFF time. Ip2, I
b2 shows an example of a current change value during ON and OFF times of Tr2.

With this alone, the output Vo may generate a large overshoot at the time of the rise of the power supply circuit. For example, as shown in FIG. 7A, if the peak of the control reference voltage Vm is 10 V at 135 V AC, At 85 VAC
Control starts from 6.3 volts. Actually, assuming that the output power is the same, the input current may be inversely reduced as the AC input voltage increases, so that if the control is started from the inverted maximum control reference voltage Vm as shown in FIG. With the same rising characteristics, the output Vo is stabilized in a predetermined fluctuation range of the AC voltage.

This is realized by the transistor Tr5
And another variable impedance composed of resistor R7 and
If this is composed of a diode D4 that holds the peak voltage of Vin and a capacitor C3 and divided by Rd5 and Rd6 and given to Tr5, the higher the AC voltage, the lower the impedance.
Can be reduced. That is, the maximum value of the control reference voltage can be set substantially in inverse proportion to the AC voltage.

As described above, since a power supply device using an active filter can be easily configured, a hybrid IC can be easily formed at low cost except for the choke transformer 10 and is convenient for application. Therefore, even if an insulation type converter of several hundred watts or less is added, it naturally becomes expensive, but it can be realized with an allowable cost.

The power consumption of the components to be integrated into an IC depends on the output power, but is several to several tens of watts.
Is difficult due to heat dissipation.

Next, another embodiment of the inrush current preventer is shown in FIG.
Will be described. (a) Tr3 of FIG. 5 is a transistor of a different type.
Replace Tr10 and Tr11 with Dillington connection,
Even though Tr10 is driven at a constant current, the current capacity is increased and the switch power consumption is reduced. The current is about Vs / R13 between the transistor Tr12 and the resistor R13. In this way, if the constant current is Vin> Vs (about 5 volts or more), the inrush current protector operates normally. When only the resistor is used, when the base current is determined at a low voltage, an excessive current occurs when Vin becomes high. The resistors R11 and R12 prevent dark current of the transistor.

FIG. 8 (b) shows a case where the current control transistor is a field effect transistor Tr13, in which a constant current flows through the resistor R14 to generate a predetermined gate voltage. And does not change.

The capacitor C2 and the diode D2 are usually unnecessary. However, in the case of the system in which the inrush current preventer 20 is cut off when Vin is less than about 10 volts or when the overcurrent originally flows, the choke is not used. The loop forms a loop for circulating the energy stored in the transformer 10, and the capacitor capacity is set to about several tens of times the parasitic capacity of Tr2.

Next, an embodiment in which an insulation type converter is added to the power supply device using the active filter of the present invention having such a characteristic will be described with reference to FIG. The figure shows switch means 30,
This is a converter having a half-bridge configuration including the capacitors C5 and C6 and the transformer 31. Lp is a primary winding which is excited in both directions at a constant frequency in cooperation with the control winding Lc and the switch means 30. Ls is a secondary winding, and the turns ratio with the primary winding is n: 1. Lh is an auxiliary winding that creates an auxiliary power supply 33 that supplies circuit power on the secondary side. The induced voltage of the secondary winding Ls is
5, D6 rectifies and charges the intermediate capacitor C7. This charging voltage is applied to the transistor Tr14, coil 33, output capacitor
Cot, the output Eo is fed back, and Tr14 is
The output Eo is stabilized by the normal chopping method that opens and closes. The diode D7 forms a loop for charging the residual electromagnetic energy of the coil 33 to the Cot when the Tr14 is turned off. GND
2 represents secondary side grounding.

Here, assuming that the values of the capacitors C5 and C6 are C, the name of each winding is an inductance value, and the primary and secondary coupling coefficients of the transformer 31 are k, an equivalent circuit viewed from the secondary side is shown in FIG. It looks like 10. This indicates that the problem of electromagnetic radiation does not occur because the current propagated from the primary side to the secondary side is a resonance current and has few harmonics. If the resonance angular frequency ω, the characteristic impedance Z, the current Is, and the charging voltage Vc of the capacitor C7 are Z = √ (Ls (1-k ^ 2) / (2C / n ^ 2)), ω = 1 / √ ( Ls (1-k ^ 2) ・ (2C
/ n ^ 2)) Is = (Vo / 2 / n-Vc) / Z · sin (ωt). Here, the value of each component is selected based on the relationship of resonance angular frequency ω> half-bridge driving angular frequency. Note that the capacitance of the capacitor has a relationship of Cot >> C7 >> C, and the resonance angular frequency is determined by the capacitance C.

As described above, the current Is is a sine arc whose current peak changes in the charged state of the capacitor C7.

The induced voltage Vo / 2 / n of the secondary winding is output voltage.
If it is set to about 3 times or less of Eo, the inrush current at the time of power supply rise of the capacitor C7 is limited by the characteristic impedance and is about 3 times the maximum load current, which is within the allowable range. Some features are unnecessary. In the 100/117 volt system described above in which this is directly performed by the capacitor input method, a wide range of control of 80 to 190 VDC must be performed. 135 ± 41% for ± 10%
And trying to get the desired output at 80 volts, 190
In volts, the induced voltage of the secondary coil is 190/80 = 2.4 times, and in practice, the inrush current is 2.4.3 = 7.2 times, and a countermeasure is needed.

Next, another embodiment for obtaining a stabilized output Eo using the same converter system as that of FIG. 9 will be described with reference to FIG. 40 is
A drive circuit for switching the Tr 14 is provided. Reference numeral 41 denotes control means for providing an error signal of the output to the drive circuit 40. Reference numeral 42 denotes a synchronizing signal generating means synchronized with the transmission frequency of the converter from the auxiliary coil, and supplies a synchronizing signal to the control means 41. The control means 41 is controlled by the number of passages of the resonance current cycle as shown in FIG. 12A for a heavy load and as shown in FIG. 12B for a light load, and has a simple circuit configuration. A and B in the figure
Represents half cycles with different transmission phases, and the capacitors C5 and
Make sure that the charging voltage of C6 does not deviate. However, there is a defect that a relatively large ripple voltage (less than or equal to 0.2 volt) is generated because the control cycle varies.

The drive circuit 40 can also be applied to the control means 32 shown in FIG. 9, and is usually driven by a transformer. However, the drive circuit 40 is somewhat complicated due to the expensive transformer and the provision of an exciting current quenching circuit. Considering this, the drive circuit of the present invention is proposed. Zena diode, R1
5, a Tr15 and a capacitor C8 form a constant voltage circuit of Vcs = about 5 to 12 volts. Transistors Tr17 and T connected to Vcs
Complementary emitter follower for low impedance in both directions due to r18, resistor R17 has transistor Tr16 and resistor R16
A constant drive current is supplied to obtain a predetermined drive voltage, and the resistor 18 is a leakage resistor that prevents the gate voltage of the Tr 14 from becoming abnormal. The ON / OFF of the Tr 14 may be performed by rapidly charging / discharging the gate capacitance. There is almost no power consumption except during the transition period, and the drive circuit 40 has a feature that low power consumption can be realized.

The switching loss can be extremely reduced by switching the switching means 30 alternately with a dead time. From this, the converters of FIGS. 9 and 11 can obtain a conversion efficiency of 95% with an appropriate load, and the overall efficiency is 90%.
% · 0.95 of 85.5% is obtained, which is not inferior to the conversion efficiency of FIG.

The power supply device using the active filter according to the present invention has been described above. However, various modifications can of course be considered in detail.

[0042]

According to the above-described structure of the present invention, the transistors can be varied between the safe and inexpensive inrush current preventing means and the control reference voltage generating means for controlling the current viewed from the AC side so as to draw a sinusoidal arc. Since it is used as impedance and has an inexpensive configuration, it is possible to provide a power supply device using an inexpensive active filter with an improved power factor as a whole. Further, the configuration on the secondary side of the insulation type half-bridge converter added thereto is simplified, and the effect of applying the power supply device using the active filter to several hundred watts or less is great.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a commonly used capacitor input type converter.

2A is a diagram showing an AC input voltage waveform and a current waveform in FIG. 1, and a charging voltage waveform of a capacitor. FIG. (b) is a diagram showing an AC input voltage / current waveform and an output voltage waveform when an active filter according to the present invention is used.

FIG. 3 is a diagram showing a circuit / block as an embodiment of a power supply device using a conventional active filter.

FIG. 4 is a diagram showing operation waveforms of the circuit in FIG. 3;

FIG. 5 is a diagram showing a specific circuit of a power supply device using an active filter according to the present invention.

FIG. 6 is a diagram showing a partial operation of FIG. 5;

FIG. 7 is a diagram showing a control reference voltage waveform over an AC half cycle used in the present invention.

FIG. 8 is a diagram showing another specific circuit of the inrush current preventer used in the present invention.

FIG. 9 is a diagram showing a circuit in which a power supply device using an active filter according to the present invention is provided in front and a stabilized output by a chopping method is obtained on the secondary side by an insulating half-bridge converter.

FIG. 10 is a diagram showing an equivalent circuit viewed from the secondary side in FIG. 9 and a waveform of a current flowing through a secondary coil.

FIG. 11 is a diagram showing an embodiment for obtaining a secondary-side stabilized output by another method using an insulation type half-bridge converter.

FIG. 12 is a diagram showing how the number of passing current blocks changes depending on the load in the operation of FIG. 11;

[Explanation of symbols]

 2 Rectifier 3, 20 Rush current arrester 10, Choke transformer 11, 33 Auxiliary power supply 12, OSC (oscillator) 13, RS-FF (reset, set flip-flop) 14, 16, · Comparator 15 ··· Multiplier 21 ··· Control reference voltage generating means 31 ··· Transformers 32 and 41 ··· Control means 40 ··· Drive circuit 42 ··· Sync signal generating means

Claims (5)

[Claims] 1. An output from an AC (commercial) power supply through a filter.
Full-wave rectification with a rectifier to Vin, a rush current prevention means from the Vin, a choke transformer having an auxiliary coil, a main transistor for exciting the choke transformer, a loop returning to the Vin, and a choke transformer and a main transistor A step-up type comprising a storage loop for storing the excitation energy of the choke transformer in an output capacitor via a diode from a connection point, and an auxiliary power supply for supplying power to a system that rises at the Vin and is generated by an induced voltage of the auxiliary coil. A power supply device based on an active filter that obtains a DC output Vo, a, wherein the inrush current prevention means preferably includes a resistor provided on the AC power supply side of a main pole of a transistor whose control pole is driven by a constant current source. A control transistor for detecting a voltage generated at the resistor by a base-emitter saturation voltage. Means comprising a series-connected resistor and a diode for controlling the control pole to limit the maximum current of the choke transformer and initially charging the output capacitor from the connection point of the transistor and the resistor, b, the AC power source of the output Vo Output voltage detecting means for detecting an average value of about a half cycle or more, error detecting means comprising a comparator for comparing the value of the output voltage detecting means with a reference voltage Vr, c, a voltage of the Vin with a predetermined resistance A control reference voltage generating means for generating a reference voltage Vir by dividing a voltage with a variable impedance modulated by an error signal of the error detecting means, d, a transmitter for transmitting at a predetermined frequency for setting a storage means, and a current of the main transistor. When the voltage generated by the detection resistor to be detected exceeds the reference voltage Vir, the comparator releases the output to reset the storage means, and the power amplifier amplifies the output of the storage means. A driving means for driving the main transistor, wherein the pulsating current is controlled so that the current draws a sine arc when viewed from the AC power supply side, thereby suppressing a harmonic component of the AC power supply frequency and improving the power factor. A power supply device for obtaining a substantially stable DC output including: 2. The apparatus according to claim 1, further comprising another variable impedance controlled by a peak voltage holding means of said AC power supply, wherein said control reference voltage generating means is provided in parallel with said variable impedance. The power supply device according to claim 1, wherein the voltage is generated in an inversely proportional relationship with the peak voltage of the power supply. 3. An insulated half-bridge converter that receives the output Vo as an input and insulates a primary side and a secondary side, and has an intermediate capacitor directly disposed on the secondary side by full-wave rectification. 3. The method according to claim 1, wherein the primary side and the secondary side have a resonance current coupling, and the voltage of the intermediate capacitor is added to obtain a stabilized DC output by a chopping method. Power supply. 4. An insulated half-bridge converter that receives the output Vo as an input and insulates a primary side and a secondary side, and uses a switch means by full-wave rectification on the secondary side to provide an output capacitor. 3. An apparatus according to claim 1 or 2, further comprising a circuit connected to control the number of passages of the resonance current waveform by said switch means to obtain a stabilized DC output.
A power supply according to claim 1. 5. The chopping means of claim 3 and 4, wherein said chopping means and said switch means are P-type field effect transistors, and said transistors are driven on the high voltage end side of full-wave rectification. A voltage source, a complementary emitter follower supplied with power from the voltage source, a resistor between the input terminal of the emitter follower and the high voltage terminal, and a constant voltage generated at the resistor. The power supply device according to claim 3, wherein the power supply device is executed by a current-driven drive circuit.