JPS5944967A - Power source circuit of pulse width control type switching regulator - Google Patents

Abstract

PURPOSE:To reduce the peak power of noise by forming the switching current angle pulse width in quasi-random, thereby dispersing the power of noise spectrum in frequency domain. CONSTITUTION:A switching power source 2 receives electric power from an input power source 1, and applies an output voltage to a load 3. The output of a voltage detector 6 is supplied as the variation in the voltage to a votage controlled clock oscillator 7, and when the voltage supplied to the load 3 is, for example, decreased to a value lower than the set value, it is controlled to delay the clock generating period of the clock generator 7. The output of the generator 7 is supplied as the clock frequency of a quasi-random generator 8, which generates a quasi-random pulse of the frequency band in response to the clock frequency. This quasi-random pulse is gated by a variable pulse width generator 9, and applied to the switching power source 2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pulse-width side one-way switching resonator power supply circuit, and particularly to reducing noise generated by its switching operation.

Conventionally, this type of circuit has been shown in Figure 1. In the figure, (11 is a power supply, (2) is a switching power supply, and (3) is this switching power supply t21.
1/(: Load to be connected, (4) is the oscillation circuit that is the driving frequency source of the switching power supply (2), (ri) is the output ゛, which controls the flow angle of the switching power supply (2) according to the voltage value. This is a variable pulse width circuit.

Next, the operation will be explained. The switching power supply (2) receives power from the input power supply (11) and provides a preset output power supply voltage to the load (3).

In order to control the pressure applied to the load (3) at a constant i+&, the width of the switching pulse is widened or narrowed by Q in the switching power supply (2), that is, by pulse width modulation. That goal has been achieved. Oscillator ts5i t4+ pulses 9. (This is an oscillation circuit for determining the f return frequency, and for power supply 'city control (!Sho), this oscillation frequency itself is voltage stable 10''
Since there is no 6-tone, a self-excited oscillator such as a multi-vibrator is often used for 6-oscillators. variable pulse 1
The crystal circuit (5) changes the pulse width in the pulse train of the frequency determined by the 1 oscillation circuit (4), and changes the pulse width of the input power supply (voltage fluctuation of the input power supply (11) and resistance value fluctuation of the load (3)). The pulse width is changed to w to compensate for fluctuations in the output voltage of the switching power supply (2) caused by
This is to make the output 'ton field constant.

That is, when the output voltage decreases, the pulse train is made wider, and when the output voltage increases, the pulse train is made narrower. (2)
), the flow jllj angle system ``111'' is performed.

The conventional four-way switching regulator power supply using the pulse width control method is constructed and operated as described above, so that the voltage of the human power supply (11) and the f'l load resistance of load (3) are (-(
Under stable conditions, the switching power supply (2
), it operates at a nearly constant frequency and a width of /'/L7. For this reason, the noise generated from this circuit, the frequency spectrum consisting of the end frequency components and harmonic components of the L frequency /< /l/ width, is noticeably focused on multiple specific frequency components, and the noise itself peaks. The voltage value is high throughout the sky. Such noise/sound propagates through the input and output sides of the power supply circuit (the 4th load side), or radiates into the air as radio waves, causing harm to other equipment. There were many things that affected me now.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above. By making the switching flow angle pulse width pseudo-random, the power of the noise spectrum is distributed in the frequency domain, and the peak power of the noise is reduced. The purpose of this invention is to provide a switching regulator and a power supply circuit using a pulse width control method that can measure the pulse width.

An embodiment of the present invention will be described below with reference to the drawings. Second
In the figure, (1) is a human powered power supply, (2) is a switching power supply, (3) is a load connected to this switching power supply (2), and (6) is a power supply when the voltage supplied to load (3) is as expected. A voltage detection circuit (7) is a voltage control clock generation circuit whose oscillation frequency is controlled according to the output level of the voltage detection 1rJl path (6).
) generates a pseudo-random pulse signal in a frequency band corresponding to the period based on the clock output of the voltage side clock generation circuit WIf71.The pseudo-random signal generating circuit 191 generates a pseudo-random pulse signal with a frequency band corresponding to the period of the clock output from the voltage side clock generation circuit WIf71. This is a variable pulse width generation circuit that generates and outputs a flow angle control pulse whose gate output has a constant γ rising period and whose pulse width is random.

Next, the operation will be explained. The switching power supply (2) receives input power (f; from the moon), power supply, and has a preset output? 11 pressure, it is given to 4) by itself, and the valley 1 of the signs ((5) to (9) is the one where the load is applied even if the slope ratio fluctuation, load resistance value C [i17, etc.) occur. (3) to control the voltage applied to a constant value.In other words, the voltage detection circuit (6) is connected to the output terminal of the switching power supply R source (2) (to which the load is connected i":f, A part of the output voltage is supplied from the output terminal (i), and the degree of variation in the voltage is detected.The output of this voltage detection circuit (6) is used to generate a voltage control clock as a change in the voltage. If the supply voltage supplied to the circuit (71, for example to the load (3) is 1 (-h-
-The clock generation of the clock generation circuit (7) is controlled to be slow.This voltage fttl,lIil+Iri1
The output of the cock generation circuit (71) is supplied as the clock frequency of the pseudorandom signal generation circuit !+'Rf81, and the pseudorandom signal generation circuit (8) generates and outputs pseudorandom pulses in a frequency band corresponding to this clock frequency. This pseudo-random pulse is generated by a variable pulse width generation circuit (9).
is gated by a gate pulse with a constant period, and the flow angle system (
Goods) A pulse is generated and the flow angle of the switching power supply (2) is controlled by this pulse. As described above, in the control method according to the present invention, the switching frequency as a switching power supply circuit is constant, and the pulse width changes in a pseudo-random manner. The cumulative flow time within a certain period of time is automatically controlled to make the output voltage a constant value, such as increasing or decreasing depending on the output voltage.

In addition, in the above practical example, an example is shown in which a voltage detection circuit (6) is provided, but this is because the voltage control tarlock is generated W, ! 7
It is not an essential element as long as the control sensitivity and polarity of 1 are appropriate.

As described above, according to the present invention, since the pulse width for controlling the flow angle of the pulse width control type switching regulator power supply circuit is changed pseudo-randomly,
Since the 1J frequency noise spectrum generated from this power supply circuit is dispersed in the frequency domain, troubles such as interference at specific frequencies are reduced, and the tth noise suppression method, 1' + ti, is simplified. It has the effect of reducing costs.

[Brief explanation of the drawing]

FIG. 1 shows system IX1. Second
FIG. 5 is a system diagram illustrating a circuit according to an embodiment of the present invention. In the figure, (2) is the switch power supply, (8) is ↑1τ, the pressure detection circuit ~, +71 is the voltage-controlled clock generation -1 circuit,
(81 is a pseudo-random signal generation circuit, (91 is a variable pulse width generation circuit Ilj'1. The same reference numeral in the figure indicates the same part or 411. Substitute hitter Nobu Kuzuno-

Claims (1)

[Claims] In the Hals width control type switching V regulator '1u source circuit, the flow angle control φ reference pulse width 'fc4 pseudo-random pulse width is used, and the cumulative pulse width within a constant 1Ijj is determined by the blue range to output 'tEI:f. Pulse width control force type S/F control (characterized by rounded pulse width control)
Yuubamoto circuit.