JPH05111251A - Stabilized power source - Google Patents

Abstract

(57) [Abstract] [Purpose] In a stabilized power supply device used for various electric devices, a stabilizing circuit composed of a resistor in the switching part of a switching regulator, transformer winding,
The purpose of the present invention is to provide a stabilized power supply device that has excellent characteristics by eliminating variations in coupling degree. [Structure] The control circuit unit 13, the output voltage detection circuit 15,
In the switching regulator including the switching circuit unit 11, the switching circuit unit 11 includes a transformer circuit unit 12 and a smoothing filter 14. By providing the stabilizing circuit 20 including a resistor between the transformer circuit unit 12 and the smoothing filter 14, the overshoot voltage of the switching output voltage is eliminated, and a highly accurate and stable output voltage can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stabilized power supply device which can be used in general electric equipment.

[0002]

2. Description of the Related Art In recent years, stabilized power supply devices have been made in various ways.

An example of the above-described stabilized power supply device will be described below with reference to the drawings. FIG. 5 is a block diagram of a conventional stabilized power supply device. Reference numeral 51 is a switching circuit section of a switching regulator, 52 is a transformer circuit section which constitutes the switching circuit section 51, 5
Reference numeral 4 is a smoothing filter that constitutes the switching circuit unit 51, 53 is a control circuit unit that controls the switching circuit unit 51, and 55 is an output voltage detection circuit that transmits information on the output voltage to the control circuit unit 53. FIG. 6 shows a configuration diagram of a conventional stabilized power supply device. A transformer circuit unit 52 is composed of a transformer, a transistor and a diode, a smoothing filter 54 is composed of a coil and a capacitor, and an output voltage detection circuit 55 is a resistor. The control circuit 53 includes a reference voltage, an amplifier, a reference triangular wave, and a comparator.

FIG. 4 is a diagram showing the circuit operation of the conventional stabilized power supply device, which is a waveform showing the switching operation indicated by 63 in FIG. T is ON period of the cycle of the switching operation, T ₁ is the switching operation, (T-T ₁₎ is intended to indicate the OFF period of the switching operation, V _1,
V _2, -V _3, -V ₄ represents the output of the transformer circuit.

The operation of the conventional stabilized power supply device configured as described above will be described below.

First, the control circuit 53 internally has a reference voltage and a reference triangular wave for PWM control. The output voltage detection circuit 55 detects the output voltage B, and the control circuit 5
Communicate information to 3. The control circuit 53 compares the reference voltage with the detection information, and performs PWM control using the internal triangular wave to perform switching control of the switching circuit unit 51 so that the output voltage B becomes a constant target voltage. The transformer circuit section 52 has an output A and an output C in addition to the output B of the reference control voltage, and outputs the output voltages A and B depending on the winding ratio with respect to the duty of the reference control voltage. The state of the operation is as shown in FIG. Figure 4
Represents the voltage waveform of the switching circuit unit 51, T represents the cycle of the switching operation, T ₁ represents the ON cycle of the switching transistor, and (T−T ₁ ) represents the OFF cycle of the switching transistor. Also, (V ₁ + V ₂ )
Represents the voltage value of the ON period of the output _{A, - (V 3 + V} 4)
Shows the voltage value of the ON cycle of the output C. The switching cycle and the ON cycle of the output B are exactly the same, and the voltage according to the winding ratio is (V ₁ + V ₂ )-
It becomes (V ₃ + V ₄ ). The smoothing filter 54 operates as a filter that smoothes the pulse voltage of the ON cycle and the OFF cycle of the T cycle into a DC voltage, and sends a stable voltage to the output.

[0007]

However, in the above structure, the winding method of the winding of the switching transformer,
The variation in the coupling degree of winding, V ₂ of FIG. 3, variations occur in overshoot voltage during the switching operation represented by -V _3. The switching regulator is
The averaged voltage of the ON period (H) and the OFF period (L) is output, and variations in the overshoot voltage cause variations in the averaged output voltage. However, there is a problem that the target stable and highly accurate voltage cannot be obtained, and the voltage guarantee for the load element cannot be satisfied.

In view of the above problems, the present invention includes a resistor that absorbs an overshoot voltage at the time of switching operation between a transformer that constitutes a switching regulator and a filter that smoothes the output voltage, and an averaged output voltage. The present invention provides a stabilized power supply device capable of stably outputting an output voltage even if variations occur in the winding method of the transformer and the coupling degree of the windings by maintaining the constant value.

[0009]

In order to solve the above problems, a stabilized power supply device of the present invention comprises a transformer forming a switching regulator, a filter for smoothing a switching output voltage, and a transformer provided between the transformer and the filter. It is provided with a stabilizing circuit composed of a resistor.

[0010]

According to the present invention, the resistor provided between the transformer of the switching regulator and the filter for smoothing the switching output voltage has the above-described structure, and the variation of the overshoot voltage of the switching output voltage generated by the variation of the switching transformer is provided. Therefore, the averaged output voltage of the switching output voltage can be made uniform, and a stable and highly accurate output voltage can be supplied.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A stabilized power supply device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a stabilized power supply device according to an embodiment of the present invention. In FIG. 1, 11 is a switching circuit part of a switching regulator, and 1 is a switching circuit part.
Reference numeral 2 is a transformer circuit portion which constitutes the switching circuit portion 11, 14 is a smoothing filter which constitutes the switching circuit portion 11, 13 is a control circuit portion which controls the switching circuit portion 11, 15 is control circuit portion 13, and output voltage information. Is a stabilizing circuit provided between the transformer circuit section 12 and the smoothing filter 14.

FIG. 2 is a block diagram of the stabilized power supply device according to the embodiment of the present invention.
It is composed of a transformer, a transistor and a diode, the smoothing filter 14 is composed of a coil and a capacitor, and the stabilizing circuit 20 is composed of a resistor. The output voltage detection device 15 is composed of a resistor, and the control circuit unit 13 is composed of a reference voltage, an amplifier, a reference triangular wave, and a comparator.

FIG. 3 shows an operation waveform diagram of the stabilized power supply device according to the embodiment of the present invention. T is a cycle of the switching operation, T ₁ is an ON cycle of the switching operation, and (T-
T ₁ ) indicates the OFF cycle of the switching operation. V ₁ ′, V ₂ ′, −V ₃ ′ and −V ₄ ′ in FIG. 3 are output voltages of the stabilizing circuit.

The operation of the stabilized power supply device configured as described above will be described below with reference to FIGS. 1, 2 and 3. First, the control circuit 13 internally has a reference voltage and a reference triangular wave for PWM control. The output voltage detection circuit 15 detects the output voltage B, and the control circuit 13
Communicate information to. The control circuit 13 compares the reference voltage with the detection information, and performs PWM control using the internal triangular wave to perform switching control of the switching circuit unit 11 so that the output voltage B becomes a constant target voltage. The transformer circuit section 12 has outputs A and C in addition to the output B of the reference control voltage, and outputs the output voltages A and B depending on the winding ratio with respect to the duty of the reference control voltage. The operation is as shown in FIG. V ₁ ′ and V ₂ ′ in FIG. 3 are output voltage waveforms of the stabilizing circuit 20 for the output A. The overshoot voltage (V ₂ ) at the output of the transformer circuit 12 is absorbed by the stabilizing circuit 20 (resistor), and the waveform of V ₂ ′ at the output of the stabilizing circuit 20 becomes almost zero, resulting in an ideal pulse voltage waveform. This pulse waveform is smoothed by the smoothing filter 14, and a stable and highly accurate DC voltage is supplied. Also, the output C-
Although V ₃ and −V ₄ are negative output voltages, the same operation is performed and a stable and highly accurate DC voltage is supplied.

As described above, according to the present embodiment, the stabilizing circuit composed of the transformer forming the switching regulator, the filter for smoothing the switching output voltage, and the resistor provided between the transformer and the filter is provided. By providing the transformer, even when the windings and the coupling degree of the transformer vary, it is possible to eliminate the variation of the output voltage which is the average voltage of the switching output voltage and to supply a stable and highly accurate output voltage.

[0017]

As described above, the present invention provides a stabilizing circuit including a transformer that constitutes a switching regulator, a filter that smoothes a switching output voltage, and a resistor that is provided between the transformer and the filter. By providing the transformer, it is possible to eliminate the variation of the output voltage which is the average voltage of the switching output voltage due to the variation of the winding of the transformer and the degree of coupling, and it is possible to obtain a highly accurate and stable output voltage with a simple circuit and at low cost. Further, since the stabilizing circuit has a simple circuit configuration, it is possible to obtain an excellent effect that an arbitrary constant can be easily set.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram of the same embodiment.

FIG. 3 is an operation waveform diagram in the example.

FIG. 4 is an operation waveform diagram in a conventional example.

FIG. 5 is a block diagram of a stabilized power supply device in a conventional example.

FIG. 6 is a circuit diagram of a conventional example.

[Explanation of symbols]

 11 Switching Circuit Section 12 Transformer Circuit Section 13 Control Circuit Section 14 Smoothing Filter 15 Output Voltage Detection Circuit 20 Stabilization Circuit

Claims (1)

[Claims] 1. A stabilizing circuit comprising a transformer constituting a switching regulator, a filter for smoothing a switching output voltage, and a resistor provided between the transformer and the filter. Stabilized power supply.