JPS5869462A - Rectifying power source circuit with ripple reduction control circuit - Google Patents

Abstract

PURPOSE:To reduce the size and weight of a rectifying power source circuit and to remove the low frequency noise and vibration by connecting a high frequency switching regulator to the power source circuit and compensating the ripple voltage generated by negative control. CONSTITUTION:A switching regulator is composed of a transformer 15, a rectifying circuit 16, a smoothing circuit 17, a switching element 18 and a voltage vs. pulse converter 19. This regulator control circuit is formed by connecting the output side of the converter 19 connected at the input side between the terminals 20 and 21 to the control input terminal of the element 18. In this manner, negatie feed back control is performed in the regulator to remove the ripple of the output voltage of the rectifying power source circuit. Thus, the ripple can be readily removed without using a large filter, thereby reducing the size and weight of the power source and removing the noise and vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rectifier power supply circuit equipped with a ripple reduction control circuit.

Generally, a ripple filter is used in a rectifying power supply circuit for obtaining a DC voltage from an AC voltage to prevent ripple from being applied to the load. This kind.

An example of a conventional power supply circuit is shown in FIG. In this figure, 1 is an AC power supply, 2 is a rectifying bridge diode, and 3.5 is a smoothing coil.

4.6 is a smoothing capacitor. In this circuit,
Coils 3 and 5 and capacitors 4 and 6 constitute a ripple filter, and in order to suppress ripples that occur on the output side, these values must be made sufficiently large, and the weight and volume of the entire power supply circuit must be This has the disadvantage of not only increasing the noise but also generating low-frequency noise and vibration from the coils and the like.

An object of the present invention is to eliminate the above-mentioned conventional drawbacks by adding a ripple reduction control circuit to a rectification power supply circuit, and to provide an economical rectification power supply circuit that is small, lightweight, and does not generate low-frequency noise or vibration. It is in.

According to the present invention, the DC
-1,) Connect one of the input and output ends of the 0 conversion type switching regulator.

The other input end of the switching regulator is connected to the other output end of the rectifying power supply circuit.

and a voltage-to-pulse conversion circuit is connected between the other output end of the switching regulator and the other output end of the rectifying power supply circuit, and the output side of the voltage-to-pulse conversion circuit is connected to the switching regulator. By connecting to the control input terminal of the switching regulator, the output voltage between the other output terminal of the switching regulator to which a load is connected and the other output terminal of the rectifying power supply circuit is controlled to be constant. A rectifying power supply circuit equipped with a ripple reduction control circuit featuring the following characteristics is obtained.

Next, an example will be given of a rectifying power supply circuit according to the present invention.
This will be explained with reference to the drawings.

This is what is shown. In this figure, 11 is an AC power supply, and 12 is a rectifying bridge diode.

13 is a smoothing coil, and 14 is a smoothing capacitor.

15 is a high frequency transformer, 16 is a rectifying circuit, 17 is a smoothing circuit, 18 is a switching element, and 19 is a voltage-to-pulse conversion circuit. In such a circuit, the coil 13 and the capacitor 14 constitute a smoothing circuit according to the prior art.

Since the inductance value of the coil 13 and the capacitance value of the capacitor 14 are smaller than the values set in a normal power supply, the output voltage obtained across the capacitor 14 has a non-negligible residual ripple voltage. appear. Also.

Trance 15. Rectifier circuit 16. Smoothing circuit 17. The switching element 18 and the voltage-to-pulse conversion circuit 19 constitute a switching regulator, and the input side of this regulator is connected to both ends of the capacitor 14. This switching regulator compensates for the residual ripple voltage, as seen in waveform B in FIG. 3, and provides a ripple-free output voltage between output terminals 20 and 21. Note that in FIG. 3, waveform A shows an output waveform including ripples appearing at both ends of the capacitor 14.

Waveform B shows the output voltage between terminals 20 and 21 that has been made constant by adding the controlled output voltage of the switching regulator shown with diagonal lines.

The control circuit of the switching regulator is connected to terminals 20 and 2.
The voltage-to-pulse conversion circuit 1 is formed by connecting the output side of the voltage-to-pulse conversion circuit 19 whose input side is connected between the voltage-to-pulse conversion circuit 1 and the control input terminal of the switching element 18.
The reference numeral 9 outputs, for example, a pulse whose width is changed according to the value of the DC voltage applied as an input as a converted output to the output side, and in a stable operating state.

When the DC voltage shown in waveform B is applied, a pulse with a preset width is applied to the switching element 18 as a control input. As a result, the regulator performs negative feedback control to remove ripples in the output voltage of the rectifier power supply circuit (=r>f voltage across the fuser 14). In other words, for residual ripple voltage that cannot be removed by the rectifier power supply circuit.

The switching regulator generates a voltage that can sufficiently compensate for this, thereby absorbing the residual ripple component.

FIG. 4 shows a circuit diagram of a second embodiment of the present invention. In the figure, 11 to 14 indicate the same elements, as shown by the same reference numerals in the embodiment shown in FIG. 3 above. 22 is a high frequency transformer, 23 and 24 are diodes, 25 is a smoothing coil, 26 is a smoothing capacitor, 27 is a switching element, 28 is a comparator for voltage to pulse conversion, and 29 is a driver. In this circuit, elements 22 to 29 constitute a switching regulator, which performs control to remove ripples in the same manner as in the first embodiment. A reference triangular wave to be compared with the input DC voltage is applied from the terminal 32 to the comparator 28 connected on the input side between the output terminals 30 and 31.
In a steady state, a pulse with a predetermined width is output. In Figure 5, which shows the operating waveforms of this example, waveform A is the output voltage of the rectification and power supply circuit (voltage across capacitor 14) before ripple removal, and waveform B is the ripple in the shaded area removed by the switching regulator. The output voltage between output terminals 30 and 61 is shown.

In addition, in the first and second embodiments described above, one example of the switching regulator was shown, but in addition to these, there are also forward switching type, push-pull type, flyback type, bridge type, etc. Many methods can be applied, such as: It goes without saying that, as a voltage-to-pulse conversion circuit, in addition to comparison circuits using triangular waves, circuits that change the number of pulses such as pulse width modulation circuits, noise number modulation circuits, pulse frequency modulation circuits, etc. can be applied. .

As is clear from the above description, according to one aspect of the present invention, a high-frequency switching regulator is connected to a rectified power supply circuit, and the ripple voltage generated by negative control is compensated for.

It is possible to easily remove ripples without using a large ripple filter as in the prior art, and it has great effects such as being smaller and lighter, as well as being able to eliminate noise and vibration.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing an example of a conventional rectifier power supply circuit;
FIG. 3 is a circuit diagram showing a first embodiment of the present invention, FIG. 3 is a diagram showing operating waveforms in the embodiment of FIG. 2, and FIG. 4 is a circuit diagram showing a second embodiment of the present invention. FIG. 5 is a diagram showing operating waveforms in the embodiment of FIG. 4. In the figure, 1.11 is an AC power supply, 2.12 is a bridge diode, 3, 5.13 is a smoothing coil, and 4
゜6.14 is a smoothing capacitor, 15.22 is a high frequency transformer, 16 is a rectifier circuit, 17 is a smoothing circuit, 18゜27 is a switching element, 19 is a voltage to pulse conversion circuit, 23.24 is a diode, 25 is a high frequency coil for,
26 is a high frequency capacitor, 28 is a voltage-to-pulse/sparse conversion comparator, and 29 is an id driver. Introduction figure 1 - m 1 hour figure 3 111 time darkness figure 5

Claims (1)

[Claims] 1. Connect one of the input and output ends of a DC-Do conversion switching regulator to one of the output ends of the rectifying power supply circuit, and connect the input end of the switching regulator to the other of the output ends of the rectification power supply circuit. and a voltage to pulse conversion circuit is connected between the other output end of the switching regulator and the other output end of the rectifying power supply circuit, and the output side of the voltage to pulse conversion circuit is connected to the switching regulator. By connecting to the control input terminal of the regulator, the output voltage between the other output terminal of the switching regulator to which a load is connected and the other output terminal of the rectifying power supply circuit is controlled to be constant. A rectifier power supply circuit equipped with a ripple reduction control circuit.