CN108631548A

CN108631548A - A kind of power supply frequency hopping circuit

Info

Publication number: CN108631548A
Application number: CN201710172354.8A
Authority: CN
Inventors: 谭磊
Original assignee: SG Micro Beijing Co Ltd
Current assignee: SG Micro Beijing Co Ltd
Priority date: 2017-03-22
Filing date: 2017-03-22
Publication date: 2018-10-09
Anticipated expiration: 2037-03-22
Also published as: CN108631548B

Abstract

The present invention relates to a kind of power supply frequency hopping circuits.Including switching oscillator FF, timing oscillator FC, latch L, counter C and trigger R；Reset flip-flop R when saltus step occurs for the output voltage UT of the timing oscillator FC, the failing edge of the CLK signal of counter C set flip-flop R again, trigger R outputs at this time make the state of latch L latching accumulators C, the output end of trigger R generates the switching frequency of control Signal-controlled switch oscillator FF, to control the closing and conducting of switching tube in Switching Power Supply.The Switching Power Supply and timing control of the present invention uses two oscillators, intercepts and captures counter status to high-speed oscillator count random using the shake and cycle counter of low speed oscillator to realize the scheme of frequency hopping.

Description

A kind of power supply frequency hopping circuit

Technical field

The present invention relates to Switching Power Supply control field, specifically a kind of power supply frequency hopping circuit.

Background technology

In the prior art, when the Switching Power Supply of multiple frequencies works on a busbar, it is susceptible to beat frequency phenomenon, Make to occur on busbar significantly low-frequency fluctuation and the problems in electromagnetic interference frequency range excessively collects.Frequency hop spread spectrum is switching Field of power supplies application mostly uses an independent triangular wave and controls a voltage controlled oscillator frequency sweep or one in a certain range The control of pseudorandom sequence controller is beated between several frequency points to be realized.

But at present currently existing scheme it is complex, need using pseudo-random sequence generator, special white noise sound source or Person's linear frequency sweep circuit is realized.

Beat frequency phenomenon：When two little processes of frequency phase-difference work together, phase presses the difference of two frequencies alternately Occur with phase and reverse phase；This stablizes with low frequency mutually reflected by power supply or other processes with reverse phase and undesirable Wave phenomenon, that is, beat frequency phenomenon.

Frequency hopping spread spectrum：Artificially make the process i.e. frequency hopping that frequency changes in a certain range.One of purposes of frequency hopping is to keep away Exempt from beat frequency phenomenon occur and electromagnetic interference is avoided steadily to appear in certain frequency range.

Invention content

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a kind of power supply frequency hopping circuits.It solves Technical problem：The Switching Power Supply of multiple frequencies, which occurs beat frequency when working on a busbar, makes occur significantly low frequency wave on busbar Dynamic and electromagnetic interference frequency range the problems in excessively collects.

To achieve the above objectives, the technical solution adopted by the present invention is that：

A kind of power supply frequency hopping circuit, including switching oscillator FF, timing oscillator FC, latch L, counter C and triggering Device R；

The timing oscillator FC is connect with the R input of trigger R, and the output voltage UT of timing oscillator FC is jumped Reset flip-flop R when change；

The S input terminals of the trigger R are connect with counter C, and the output end of trigger R is connect with latch L, counter C is connect with latch L, and switching oscillator FF is connect with latch L,

Again set flip-flop R, the control signal of trigger R outputs at this time make lock to the failing edge of the CLK signal of counter C The state of storage L latching accumulators C, and the switching frequency of switching oscillator FF is controlled, to control switching tube in Switching Power Supply It closes and is connected.

On the basis of said program, the counter C is cycle counter.

On the basis of said program, the trigger R is the RS registers of edging trigger.

On the basis of said program, the timing oscillator FC exports UTO signals, UTO signals to switching power circuit It is the fundamental unit time signal of the UT outputs of timing oscillator FC, is used for the control operation timing of switching power circuit.

On the basis of said program, the switching oscillator FF is used to generate the switching frequency of switching power circuit.

On the basis of said program, the switching oscillator FF exports SFO signals, SFO signals to switching power circuit It is to be determined by the clock frequency signal SWCLK inside switching oscillator FF.

On the basis of said program, the SFO signals are exported to the switch modulator part of switching power circuit, are used for Control the working frequency of power modulators in switching power circuit.

On the basis of said program, when the frequencies of the SWCLK signals is higher than the frequency of SFO signals, need from Increase a frequency unit on the signal flow path of SWCLK to SFO.

In power supply frequency hopping circuit of the present invention, Switching Power Supply and timing control use two oscillators, utilize low speed The shake of oscillator (i.e. timing oscillator FC) and cycle counter are to high-speed oscillator (i.e. switching oscillator FF) count random Intercept and capture the scheme that counter status is used for realizing frequency hopping.Circuit structure of the present invention is succinct, and hardware spending is small.Using periodically shaking The timing noise for swinging device itself generates spread spectrum effect.When the Switching Power Supply of multiple frequencies works on a busbar, will not go out The problems in existing beat frequency makes to occur on busbar significantly low-frequency fluctuation and electromagnetic interference frequency range excessively collects.

Description of the drawings

The present invention has following attached drawing：

The structure chart of Fig. 1 present invention.

Specific implementation mode

Below in conjunction with attached drawing, invention is further described in detail.

As shown in Figure 1, power supply frequency hopping circuit of the present invention, including：Switching oscillator FF, timing oscillator FC, lock Storage L, counter C and trigger R；

This programme generates spread spectrum effect using the timing noise of timing oscillator itself.Switching oscillator FF is opened for generating Powered-down source circuit switching frequency, it has several adjusting positions to be used for adjusting working frequency；Switching oscillator FF in Fig. 1 uses 3 Binary digit controls weighted current source and generates 8 optional Frequency points.Timing oscillator FC is that control is generated in switching power circuit The oscillator of operation timing processed；The oscillator makes it export scheduled frequency Fc by trimming.Switching oscillator FF and timing are shaken The circuit module that device FC is generally existing in switching power circuit is swung, is not new hardware spending；Realize the newly-increased circuit of spread spectrum That is latch L, counter C and a trigger R.

Counter C is a cycle counter, and trigger R is the RS registers of edging trigger.Timing oscillator FC's is defeated Go out UT and reset flip-flop R when saltus step occurs every time, and set triggers the failing edge of the CLK of next counter C outputs again Device R；At this moment trigger R outputs make the state of latch L latching accumulators C, and generate control signal to control Switching Power Supply Switching tube S1~S3 closing and conducting.The frequency of Switching Power Supply is far above the frequency for controlling operation timing clock, UT's The shake Jf in a large amount of Ff periods in a cycle is homogenised for, and only retains low frequency part；The frequency difference makes smaller Jc simultaneously Several Ff periods may be covered.

This programme is (to be opened high-speed oscillator using the larger low speed oscillator (i.e. timing oscillator FC) of jittering noise Close oscillator FF) cycle count state, it is used in combination collected circulating technology state to control high in next low speed oscillator period The frequency of fast oscillator.It is estimated with the high-speed oscillator of the low speed oscillator of 10Hz and 1MHz, the 10ppm shakes of 10Hz can make Occurs the difference of 1 clock when the state of latching accumulator C.As long as confirming that the shake of low speed oscillator is more than high speed by emulation 1 period of oscillator may occur in which macrocyclic frequency hopping effect.Go out when the shake is close to the counter C full range times Now uniform frequency hopping；And further increasing shake no longer improves the uniformity that each frequency occurs.

Actual circuit realizes the frequency difference that can pull open two oscillators as needed, such as further divides using to SFO After frequency method of the frequency of SWCLK without improving Switching Power Supply frequency is used, improves to the switching power circuit that frequency determines again Pull open the difference of two frequencies.In this way, the frequency of the aforementioned value update switching oscillator FF using UT timing interception counters C has There is randomness, that is, realizes random frequency modulation.

A part of this circuit as switching power circuit, SFO is this circuit output to Switching Power Supply herein Switch modulator part, for controlling the signal of the working frequency of power modulators in Switching Power Supply；UTO is other action timings Device UT is output to the fundamental unit time signal of other parts.SWCLK is the clock frequency inside FF oscillators, SFO be with Frequency obtained based on SWCLK, SWCLK is greater than or equal to SFO.Fig. 1 performances are the consistent feelings of SWCLK with SFO frequencies Condition；The situation of SWCLK ratios SFO high needs to increase a frequency unit on the signal flow path from SWCLK to SFO.

The content not being described in detail in this specification belongs to the prior art well known to professional and technical personnel in the field.

Claims

1. a kind of power supply frequency hopping circuit, it is characterised in that：Including switching oscillator FF, timing oscillator FC, latch L, count Device C and trigger R；

The timing oscillator FC is connect with the R input of trigger R, when saltus step occurs for the output voltage UT of timing oscillator FC Reset flip-flop R；

The S input terminals of the trigger R are connect with counter C, and the output end of trigger R is connect with latch L, counter C with Latch L connections, switching oscillator FF are connect with latch L,

Again set flip-flop R, the control signal of trigger R outputs at this time make latch L to the failing edge of the CLK signal of counter C The state of latching accumulator C, and control the switching frequency of switching oscillator FF, with control in Switching Power Supply the closing of switching tube and Conducting.

2. power supply frequency hopping circuit according to claim 1, it is characterised in that：The counter C is cycle counter.

3. power supply frequency hopping circuit according to claim 1, it is characterised in that：The trigger R is that the RS of edging trigger is posted Storage.

4. power supply frequency hopping circuit according to claim 1, it is characterised in that：The timing oscillator FC is to switch power supply Road exports UTO signals, and UTO signals are the fundamental unit time signals of timing oscillator FC outputs, for switching power circuit Control operation timing.

5. power supply frequency hopping circuit according to claim 1, it is characterised in that：The switching oscillator FF is for generating switch The switching frequency of power circuit.

6. power supply frequency hopping circuit according to claim 1, it is characterised in that：The switching oscillator FF is to switch power supply Road exports SFO signals, and SFO signals are determined by the clock frequency signal SWCLK inside switching oscillator FF.

7. power supply frequency hopping circuit according to claim 6, it is characterised in that：The SFO signals are exported to switch power supply The switch modulator part on road, the working frequency for controlling power modulators in switching power circuit.

8. power supply frequency hopping circuit according to claim 6, it is characterised in that：The frequency of the SWCLK signals is believed higher than SFO Number frequency when, on the signal flow path from SWCLK to SFO increase a frequency unit.