JPS63249467A - Power source - Google Patents

Abstract

PURPOSE:To improve the conversion efficiency of a power source by charging a capacitor with an output voltage to a load, and discharging the capacitor to supply it to the load when the potential difference between the charging voltage and the load voltage shows a predetermined value. CONSTITUTION:A power source 10 inputs a desired AC voltage from a diode bridge 2, full-wave rectifies it, and outputs the rectified voltage Vin from output terminals (a), (b). A smoothing condenser C10 is charged by a second diode D12 forwardly connected to the output terminal (a). In this case, a load 3 is supplied with power through a first diode D11, the output voltage VOUT2 at this time is detected by a series circuit of a resistor R1 and a Zener diode ZD forwardly connected, and a thyristor TH is driven. When the difference between the output voltage VOUT2 and the voltage of the capacitor C10 exceeds a Zener voltage, the thyristor TH is made conductive to supply power from the capacitor C10 to the load 3.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a power supply device, and can be applied, for example, to a power supply device that rectifies a commercial power source to obtain a predetermined DC voltage.

B Summary of the Invention The present invention provides a power supply device that outputs a rectified voltage obtained through a rectifier circuit to nine loads, charges a capacitor, and causes the charge charged in the capacitor to become higher than the rectified voltage by a predetermined potential difference. By discharging the charge stored in the capacitor and supplying it to the load, a power supply device with high conversion efficiency from AC voltage to DC voltage using a small capacitance capacitor can be obtained.

C. PRIOR TECHNOLOGY Conventionally, in this type of power supply device, one in which a commercial power supply consisting of an alternating current voltage is rectified and a direct current voltage is supplied to a predetermined load has been used.

That is, in FIG. 4, the power supply device 1 converts commercial power into a desired alternating current voltage AC via, for example, a power transformer (not shown), and then converts it into a desired alternating current voltage AC through four diodes D1, D2, D.
3 and D4 are connected in a quadrilateral manner to a diode bridge circuit 2, which performs full-wave rectification to obtain a full-wave rectified voltage V 1 H.

Next, the full-wave rectified voltage V1.4 is applied to the smoothing capacitor C1.
The DC voltage V is smoothed through the DC voltage V and thus includes a pulsating current component as shown in FIG. UT+ is the load resistance R
8 is supplied to both ends of the load 3.

DC voltage V applied to load 3. The pulsating flow component of ut+ is
Before the peak (indicated by the voltage value ■) of each waveform of the full-wave rectified voltage ■1 (indicated by the broken line in FIG. 5) output from the diode bridge circuit 2, the full-wave rectified voltage VIN directly eclipses fi73. During the period TA during which the smoothing capacitor C0 is charged after the peak of each waveform is discharged and applied to the load 3, the full-wave rectified voltage VIN
In line with the rising edge of the waveform, the minimum secured voltage V 141
A discharge period T for obtaining N + is alternately repeated.

Therefore, the DC voltage ■. LIT+ has a full-wave rectified voltage V
It includes a pulsating flow component at the level of the difference between the peak value of IN and the minimum ensured voltage VMINI.

However, in practice, the DC voltage supplied to the load should have as small a level of pulsating current components as possible and be close to a constant voltage value, which would be more efficient in terms of power usage efficiency and load operating efficiency. It can be said that it is a good power supply device.

Therefore, the DC voltage V of the power supply device 1. In Ua,
By making the discharge period T of the smoothing capacitor CI longer,
Minimum guaranteed voltage■. It is conceivable to increase the voltage value of 114I, thereby lowering the level of the pulsating flow component.

Here, the discharge period Tll is the angular frequency of the alternating current voltage AC
Assuming that the peak voltage value of the full-wave rectified voltage V 1 H is V, the minimum ensured voltage V HI N + exists on the waveform of the full-wave rectified voltage VIN, so the following formula % formula % (1), and as a result, if the minimum secured voltage VMIN+ is set to a higher voltage value than the full-wave rectified voltage VIN including the peak voltage value V, the discharge period T will be correspondingly longer. I know what will happen.

On the other hand, the popularity of smoothing capacitor C3 is the resistance RK of load 3.
The following formula obtained from the relationship between the time constant of the smoothing capacitor C3OCR and the time constant of the smoothing capacitor C3OCR is modified to be expressed as the following formula.

Therefore, in order to increase the minimum ensured voltage 1, 11 and lengthen the discharge period Tm, a capacitor with a larger capacity is required as the smoothing capacitor CI.

D Problems to be Solved by the Invention However, when trying to use a capacitor with a larger capacity as the smoothing capacitor C1, it is inevitable that the external shape of the capacitor itself will increase, and as a result, the power supply itself will become larger. There was a problem in that it was large.

The present invention has been made in consideration of the above points, and eliminates the need to use a large capacity capacitor as a smoothing capacitor.
This paper attempts to propose a power supply device with high conversion efficiency from AC voltage to DC voltage.

E Means for Solving the Problems In order to solve the problems, the present invention provides 6 a rectifier circuit 2 that rectifies an alternating current voltage AC and outputs a rectified voltage Vl11, and a pair of output terminals a of the rectifier circuit 2. , a first diode DIl and a load resistor RK connected in series between
, a second diode D12 and a capacitor CIG connected in series between output terminals a and b, and a first diode D.
The potential difference between the connection point C of ll and load resistor RK and the connection point d of the second diode D12 and capacitor C1° is detected, and when the potential difference reaches a predetermined value 2, the capacitor CIG is charged. Discharge circuits ZD, R4, and T to I are provided to discharge the generated charges through a load resistor RK.

During the F action predetermined period TA, the rectified voltage ■ output from the rectifier circuit 2 is supplied to the load resistor RK via the first diode Dll, and is also supplied to the capacitor via the second diode D12. Charged to C1°.

Furthermore, the electric charge charged in the capacitor C5 is the rectified voltage V
The period TA! is higher than IM and the potential difference is lower than the predetermined voltage value V2! During this period, the rectified voltage Vl1 is applied to the load resistor RK.
1 is supplied.

Subsequently, when the potential difference between the charge charged in the capacitor C1o and the rectified voltage V 1 H becomes equal to the predetermined voltage value ■2, the charge charged in the capacitor C8° is discharged instead of the rectified voltage VIN. , during the period T12 in which the charge of the capacitor CIO is equal to the rectified voltage V1H,
Supplied to load resistor RK.

G example An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, in which parts corresponding to those in FIG. 4 are indicated by the same reference numerals, 10 indicates the power supply device as a whole.

The power supply device 10 converts a commercial power source into a desired alternating current voltage AC through a transformer (not shown) as in the conventional case, inputs the converted voltage into a diode bridge circuit 2, and outputs a pair of output terminals a. From and b, a full-wave rectified voltage V is obtained by full-wave rectifying the alternating current voltage AC.

One output terminal a of the full-wave rectified voltage VIN outputted from the diode bridge circuit 2 is connected to the other output terminal A through a series circuit of a first diode Dll and a load 3 connected in the forward direction. As a result, the output terminal a is supplied to the load 3, and is also connected to the other output terminal via a series circuit of the second diode D12 and the smoothing capacitor C3° connected in the forward direction. As a result, the smoothing condenser C1° is charged.

Further, the cathode of the first diode Dll is connected to the resistor R1 and the Zener diode ZD connected in the direction of 1llJi.
is connected to the cathode of the second diode D12 through a series circuit, and the cathode of the second diode D12 is connected to the cathode of the first diode Dll through a forward-connected thyristor TH. The gate of thyristor TH is connected to the anode of Zener diode ZD.

As a result, the potential difference between the connection point C between the first diode Dll and the load 3 and the connection point d between the second diode D12 and the smoothing capacitor Cto is detected, and when the potential difference reaches a predetermined value, the smoothing The electric charge stored in the capacitor C1° is supplied to the load 3.

In the above configuration, the full-wave rectified voltage VIN output from the diode bridge circuit 2 has the waveform shown by the broken line 212th, and rises from the lowest voltage VMIN□ to the peak value ■, from the time point L1. Period T at time tztE
During A1, the full-wave rectified voltage V1,1 is supplied to the load 3 via the first diode Dll, and the smoothing capacitor C1° is charged via the second diode DI2.

At this time, since the potentials of the connection point C of the first diode Dll and negative f1η3 and the connection point d of the second diode Dl2 and the normal r:f condenser CIO are equal,
No current flows through the series circuit of resistor R1 and Zener diode ZD, and the si risk T H! It is in a reverse blocking state.

Subsequently, after the point L2 when the full-wave rectified voltage ■1.4 starts to fall from the peak value ■, the first diode D is connected to the load 3.
A full-wave rectified voltage VIN is provided through the voltage VIN. On the other hand, since the potential at the connection point d between the second diode 012 and the smoothing capacitor C1° maintains a peak of 4fiVr, the second diode D12 enters a reverse blocking state.

Also, with respect to the potential of the connection point d, the first diode Dll
As the potential at the connection point C of the load 3 falls in accordance with the fall of the full-wave rectified voltage , a reverse voltage is applied to the Zener diode ZD, and the thyristor T
A forward voltage is applied between the anode and cathode of H. However, since the gate voltage of the thyristor TH is lower than the anode voltage, the thyristor TH turns off and maintains this state.

This state is maintained until time t3 when the reverse voltage applied to the Zener diode ZD becomes higher than the Zener voltage (2).

That is, at time t3, the Zener diode ZD
A reverse current flows through the resistor R1 and the resistor R1, and thus the cyrisk TH
The voltage generated by the resistor R1 is applied to the gate of the thyristor TH, which turns on the thyristor TH, thereby discharging the charge stored in the smoothing capacitor C1°, and the peak value ■, which had been charged up to time t2, is discharged. From the voltage,
A voltage that changes according to the characteristics determined by the smoothing capacitor CIO and the CR time constant of the resistor RK of the load 3 is supplied to the load 3 as a DC voltage V 0IIT□.

Note that from this time t onwards, the potential at the connection point C between the first diode D11 and the load 3 is higher than the potential at the output terminal a of the diode bridge circuit 2, so that the first diode D
ll is in a reverse blocking state.

Next, the DC voltage due to the discharge of the smoothing capacitor CIO. At time t4, when the full-wave rectified voltage V0 rises, UTt becomes the same voltage 8°2 as the full-wave rectified voltage v1,4, the DC voltage V due to the discharge of the smoothing capacitor C1°. Since the voltages of uT□ and the full-wave rectified voltage V I N are equal, the first and second diodes D11 and 012
is turned on, and Cyrisk TH is also turned off because the voltages between the anode and cathode are equal. Note that in practice, a slight reverse bias voltage is required for the thyristor TH to turn off, so
It is designed to turn off at a timing slightly later than time t4.

Further, when the voltage value of the full-wave rectified voltage VIN increases, the load 3 is applied to the time 1.0 as described above. to time L2 and periods TA1 and TA! from time tt to time tU! During this period, a full-wave rectified voltage V□ is applied, and from time t3 to time t
During the period TRt of 4, the electric charge charged in the smoothing capacitor CIO is discharged, and the applied operation is sequentially repeated, resulting in a DC voltage ■. u7□ is supplied.

In the above configuration, in the power supply device IO, the voltage value of the full-wave rectified voltage VIN at time t when discharging by the smoothing capacitor C1 is started, and the intersection of the falling edge of the discharge and the rising edge of the full-wave rectified voltage VIH. It is considered to be an optimized state when the voltage values V DIM The discharge period T m t of the capacitor C1° is expressed by the following formula, (1
) The conventional discharge period T and the longer discharge period T shown by the formula
By substituting HE into equation (2), the minimum ensured voltage V, IN□
As a result, a higher voltage value can be obtained compared to the conventional minimum guaranteed voltage VMIN+.

Here, as shown in FIG. 3, in the conventional power supply device 1 and the power supply device 10 according to the above-described embodiment, smoothing capacitors C4 and C1° having the same capacitance are used and the same resistance R is used.
The direct tjiL voltage V supplied to the load 3 consisting of 1. Ll?
l and ■. According to an experiment comparing at□, a full-wave rectified voltage V (Fig. 3 (A)) is obtained from an alternating current voltage AC through a diode bridge circuit 2 using a conventional power supply device l.
The DC voltage V obtained by further smoothing this. DC voltage ■ obtained using the power supply device IO with respect to U□ (Fig. 3 (13)). LIT□ can obtain a DC voltage with a small level of pulsating current component by increasing the voltage value of the minimum ensured voltage VMIN□ as shown in FIG. 3(C).

According to the above configuration, in the power supply device 10, the rectified voltage VIN obtained through the rectifier circuit 2 is outputted to the load 3, and the smoothing capacitor C1° is charged, and the smoothing capacitor CIG is charged with the charge. When the potential difference between the rectified voltage V1.4 output to the load 3 reaches a predetermined value v2, the electric charge charged in the smoothing capacitor C1° is discharged and supplied to the negative 4'@3. Due to the configuration, DC voltage with low level of pulsating current component ■. The power supply device 10 that can supply the LI 72 to the load 3 can be realized.

Therefore, from the alternating current voltage AC to the direct current voltage VOtlT
A power supply device 10 with high conversion efficiency to Z can be obtained.

Further, according to the embodiment described above, the minimum secured voltage is set in the same manner as the conventional power supply device 1, and for example, the minimum secured voltages VMIN+ and VMIN! in equations (1) and (5) are set. If the relationship between the peak value and
, T, and □ have values as shown in the following formula % formula % (7). Therefore, by substituting the respective discharge periods T and T'az into formula (3), the same minimum ensured voltage can be obtained. It can be seen that in order to obtain this, the capacitance of the smoothing capacitor should be approximately 1/2 that of the conventional one.

As a result, there is no need to use a large-capacity smoothing capacitor, and the external shape of the power supply itself can be made smaller.
Can be made lighter.

In the above embodiment, the voltage applied to the thyristor and its gate is obtained by a Zener diode, and the potential difference between the charge charged in the smoothing capacitor and the voltage supplied to the load is detected, and a predetermined voltage is obtained. Although the electric charge charged in the smoothing capacitor is supplied to the load when there is a potential difference, the circuit configuration according to the present invention is not limited to this, and any circuit configuration that can perform the same operation can be applied to the above-mentioned embodiment. You can get the same effect as .

Further, in the above-described embodiment, a power supply device that obtains a DC voltage from a commercial power supply has been described, but the power supply device according to the present invention is not limited to this. For example, the power supply device according to the present invention is not limited to this. It can be widely applied to other power supply devices, such as a power supply device that obtains a DC power supply having a desired voltage value after converting the voltage into a DC power supply.

H Effects of the Invention As described above, according to the present invention, in a power supply device, a rectified voltage obtained through a rectifier circuit is output to a load, a capacitor is charged, and the charge charged in the capacitor is transferred to the load. When the potential of the output DC voltage reaches a predetermined value, the charge stored in the capacitor is discharged,
By configuring it to supply the load to the load, it is possible to supply the load with a DC voltage with a low level of pulsating current components, thus making it possible to create a power supply device with high conversion efficiency from AC voltage to DC voltage using a small capacitor. realizable.

[Brief explanation of drawings]

Fig. 1 is a connection diagram showing an embodiment of the present invention, Fig. 2 is a signal waveform diagram to explain its operation, and Fig. 3 is a comparison of the operation of the power supply device of the embodiment and a conventional power/TX device. The signal waveform diagram of the experimental example shown in Figure 4 is a connection diagram showing a conventional power supply device.
FIG. 5 is a signal waveform diagram for explaining the operation. 1.10...Power supply device, 2...Diode bridge circuit, 3...Load, C+, Coo
... Smoothing capacitor, ZD ... Zener diode, T I ... Thyrisk. υII of Momme power supply device example! Country T IF! Electricity is on the line! Harayabu 1 movement tea 2 figure polish r-1 interlayer time experiment example

Claims (1)

[Claims] A rectifier circuit that rectifies an alternating current voltage and outputs a rectified voltage, and a first circuit connected in series between a pair of output terminals of the rectifier circuit.
a second diode and a capacitor connected in series between the output terminals, a connection point of the first diode and load resistance, and a connection point of the second diode and capacitor. A power supply device comprising: a discharge circuit that detects a potential difference and discharges the charge stored in the capacitor via the load resistor when the potential difference reaches a predetermined value.