CN202424502U

CN202424502U - Switching power supply circuit

Info

Publication number: CN202424502U
Application number: CN201120526534XU
Authority: CN
Inventors: 张日光; 牛宏强; 范海涛
Original assignee: NINGBO SUNPU-OPTO SEMICONDUCTOR Co Ltd
Current assignee: NINGBO SUNPU OPTO CO., LTD.
Priority date: 2011-12-15
Filing date: 2011-12-15
Publication date: 2012-09-05
Anticipated expiration: 2021-12-15

Abstract

The utility model relates to a switching power supply circuit which comprises a rectifier and filter circuit and a power management IC (Integrated Circuit) chip. The switching power supply circuit is characterized by further comprising a quick start and protection circuit, wherein the input end of the quick start and protection circuit is connected with the output end of the rectifier and filter circuit, the output end of the quick start and protection circuit is connected with a VCC (Virtual Channel Connection) power supply end of the power management IC chip, and thus, the VCC power supply end of the power management IC chip is quickly charged. Due to the adoption of a medium-high speed start and protection modular circuit, compared with the prior art, the switching power supply circuit has the advantages that the quick start and protection circuit can charge the VCC power supply end of the power management IC chip through high current, so that the power management IC chip can quickly obtain start energy, and a whole power supply system can rapidly enter into a working state; when the power supply system enters into the working state, if a failure occurs, the power management IC chip directly enters into a halt state after the power management IC chip is powered down, so that the power management IC chip is protected; and the switching power supply circuit is simple in circuit and low in cost.

Description

A kind of switching power circuit

Technical field

The utility model relates to a kind of switching power circuit.

Background technology

Switching Power Supply has been an indispensable product in life of today; Individual Switching Power Supply is all arranged in consumer electronics product generally speaking, and its function is that the alternating current 220V/50Hz with public electric wire net is converted into the inner actual required DC direct current of electronic product.Therefore the performance of Switching Power Supply is the very important performance assessment criteria of electronic product.

Present most of Switching Power Supply is all used the inverse-excitation type transformer, the conducting through power management IC chip controls switching tube with close the further electromagnetic conversion of control transformer.Switching Power Supply its implementation of this structure is: circuit input end connects fuse EMI circuit, through rectifier bridge, AC signal is converted into direct current signal; The output branch " just " of rectifier bridge " is born " utmost point, the anodal primary coil that connects transformer, the anodal simultaneously resistance that connects; The resistance other end connects the VCC feeder ear of power management IC chip; The on off state of power management IC chip controls switching tube, switching tube come the primary coil break-make electricity of control transformer, and the secondary coil of transformer receives the magnetoelectricity conversion; Load is given in power supply, and the feedback coil of transformer receives conductor magneto-electric energy and supplies power to power management IC chip operate as normal.

The switching power circuit of this structure; After it focused on energising, the startup energy of power management IC chip power supply end will be by the positive terminal that is connected on the resistance after the rectification, and there is following shortcoming in it: the first, in order to improve power-supply system efficient; The resistance of this resistance is often all bigger; Generally all mega-ohms or more than, the VCC terminal voltage of power management IC chip rises slowlyer like this, the power management IC chip enable time is longer; If second late-class circuit breaks down, such as short circuit, energy disappears on the feedback coil of transformer; The feeder ear voltage of power management IC chip descends, and power management IC chip is shut down, and the positive pole of rectification is subsequently resumed work with the resistance of the VCC feeder ear of power management IC chip; Begin VCC feeder ear charging again to power management IC chip; Then power management IC chip is started working again, and fault still exists, and power management IC chip gets into stopped status again; Go round and begin again like this, burning appears in power management IC chip easily.

The utility model content

The utility model technical problem to be solved is to above-mentioned prior art the switching power circuit that a kind of circuit structure is simple, the system start-up time is short, protective feature is good to be provided.

The utility model solves the problems of the technologies described above the technical scheme that is adopted: this switching power circuit; Comprise current rectifying and wave filtering circuit; Power management IC chip is characterized in that: also comprise the fast protective circuit that rises, this input that plays protective circuit soon links to each other with rectification filter circuit output end; The output that should play protective circuit soon links to each other with the VCC feeder ear of power management IC chip, thereby makes the VCC feeder ear quick charge of power management IC chip.

The utility model uses a simple fast protective circuit to substitute the resistance of giving the power supply of power management IC chip enable in the prior art; Can make the VCC feeder ear quick charge of power management IC chip; Power management IC chip can get into mode of operation very soon; After power management IC chip gets into operating state; The feedback coil of transformer just can be given the VCC end power supply of IC chip, and this plays protective circuit piece will cut off the electricity supply the VCC end of Management IC chip and the current path between the rectification " positive pole " soon; When system breaks down, such as short circuit, the VCC terminal voltage of power management IC chip descends; Because having other energy, VCC do not obtain approach; So power management IC chip will get into stopped status always, to get rid of until the system failure, whole drive system just can be resumed work from newly powering on.

As improvement; Said fast protective circuit comprises first resistance, second resistance, the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance, first electric capacity, second electric capacity, first voltage stabilizing didoe, first triode, second metal-oxide-semiconductor; The cathode output end of the first termination current rectifying and wave filtering circuit of first resistance wherein; Second end of first resistance links to each other with first end of second resistance; Second end of second resistance links to each other with first end of the 3rd resistance, the cathode output end of the second termination current rectifying and wave filtering circuit of the 3rd resistance, first electric capacity and the parallelly connected formation of the 3rd resistance delay circuit; First end of the 4th resistance links to each other with the cathode output end of current rectifying and wave filtering circuit; Second end of the 4th resistance links to each other with the emitter of first triode; The base stage of first triode links to each other with second end of second resistance, and the emitter of first triode links to each other with the cathode output end of current rectifying and wave filtering circuit; The two ends of the 5th resistance link to each other with the collector and emitter of first triode respectively; The anode of first voltage stabilizing didoe links to each other with the cathode output end of current rectifying and wave filtering circuit, and the negative electrode of first voltage stabilizing didoe links to each other with the collector electrode of first triode; The two ends of second electric capacity link to each other with the two ends of the 5th resistance respectively; The 6th resistance first end links to each other with the cathode output end of current rectifying and wave filtering circuit; Second end of the 6th resistance is connected with the drain electrode of second metal-oxide-semiconductor; The source electrode of second metal-oxide-semiconductor connects the VCC end of power management IC chip, and the grid of second metal-oxide-semiconductor links to each other with the collector electrode of first triode.

Compared with prior art, the advantage of the utility model is:

1, playing protective circuit soon can make power management IC chip can obtain to start energy very soon through the VCC end charging of big electric current to power management IC chip, and whole power-supply system can get into operating state rapidly.

2, power-supply system gets into operating state, if break down, just directly gets into stopped status after the power down of power management IC chip, and power management IC chip is played a protective role.

3, circuit structure is simple, and cost is low.

Description of drawings

In Fig. 1 square frame is the circuit theory diagrams of the utility model embodiment.

Embodiment

Embodiment describes in further detail the utility model below in conjunction with accompanying drawing.

Switching power circuit as shown in Figure 1, it comprises fuse FUSE, four full-bridge rectification filter circuits 1 that diode is formed, and plays protective circuit 2 soon, power management IC chip 3 and transformer 4.Wherein play protective circuit 2 soon and comprise first resistance R 1, second resistance R 2, the 3rd resistance R 3, the 4th resistance R 4, the 5th resistance R 5, the 6th resistance R 6, first capacitor C 1, second capacitor C 2, the first voltage stabilizing didoe D1, the first triode Q1, the second metal-oxide-semiconductor Q2; The cathode output end of the first termination current rectifying and wave filtering circuit of first resistance R 1 wherein; Second end of first resistance R 1 links to each other with first end of second resistance R 2; Second end of second resistance R 2 links to each other with first end of the 3rd resistance R 3; The cathode output end of the second termination current rectifying and wave filtering circuit of the 3rd resistance R 3, first capacitor C 1 and the 3rd resistance R 3 parallelly connected formation delay circuits; First end of the 4th resistance R 4 links to each other with the cathode output end of current rectifying and wave filtering circuit; Second end of the 4th resistance R 4 links to each other with the emitter of the first triode Q1; The base stage of the first triode Q1 links to each other with second end of second resistance R 2, and the emitter of the first triode Q1 links to each other with the cathode output end of current rectifying and wave filtering circuit; The two ends of the 5th resistance R 5 link to each other with the collector and emitter of the first triode Q1 respectively; The anode of the first voltage stabilizing didoe D1 links to each other with the cathode output end of current rectifying and wave filtering circuit, and the negative electrode of the first voltage stabilizing didoe D1 links to each other with the collector electrode of the first triode Q1; The two ends of second capacitor C 2 link to each other with the two ends of the 5th resistance R 5 respectively; The 6th resistance R 6 first ends link to each other with the cathode output end of current rectifying and wave filtering circuit; Second end of the 6th resistance R 6 is connected with the drain electrode of the second metal-oxide-semiconductor Q2; The source electrode of the second metal-oxide-semiconductor Q2 connects the VCC end of power management IC chip, and the grid of the second metal-oxide-semiconductor Q2 links to each other with the collector electrode of first triode.

Above-mentioned first resistance R 1, second resistance R 2, the 3rd resistance R 3, first capacitor C, the 1 common delay circuit of forming.After power circuit powers on; To 1 charging of first capacitor C, the charging of C1 electric capacity begins by first and second resistance R 1, R2 series connection, and the voltage at its two ends begins to rise; After voltage rises to the first triode Q1 firing point; The first triode Q1 conducting, its base stage and emitter form fixedly pressure reduction, get into to continue conducting state.The effect of the 3rd resistance R 3 is after the power-supply system outage, is used for making first electric capacity return to uncharged preceding initial condition fast to 1 discharge of first capacitor C, waits for that the start next time of power-supply system powers on.

The 4th resistance R 4, the 5th resistance R 5, the first voltage stabilizing didoe ZD1, second capacitor C 2, the first triode Q1 form control circuit jointly.The 6th resistance R 6 and the second metal-oxide-semiconductor Q2 form charging circuit.After power-supply system powers on; The 4th resistance R 4 and the 5th resistance R 5 dividing potential drops are after the first voltage-stabiliser tube ZD1 voltage stabilizing, by 2 filtering of second capacitor C; Form the direct voltage drive second metal-oxide-semiconductor Q2 conducting stably, the voltage after the rectification charges to the VCC of IC chip U1 end through the 6th resistance R 6 fast.

After whole power-supply system powered on, charging circuit work provided the startup energy for the IC chip; First capacitor C 1 also begins charging therebetween, and chip enable after get into normal operating conditions greater than the start-up time of chip the time of delay of delay circuit; After the voltage at first capacitor C, 1 two ends in the delay circuit is raised to the first triode Q1 firing point; The first triode Q1 conducting, the 5th resistance R 5 voltage descend thereupon, and the voltage of keeping the lasting conducting of second metal-oxide-semiconductor descends equally; Second metal-oxide-semiconductor is closed, and the entire circuit module gets into stable state.IC chip power supply subsequently will be provided by the voltage of the feedback coil Naux of transformer T2.

After power-supply system powers on; The VCC end of IC chip is through the 6th resistance R 6 and the second metal-oxide-semiconductor Q2 quick charge; The pressure reduction between its drain D rain and the source S ource is very little after the second metal-oxide-semiconductor Q2 conducting in this process; Can ignore, the resistance of the 6th resistance R 6 is generally at the 10K or the following order of magnitude, so the charging in the time of holding very much of the VCC of IC chip end is accomplished.After delay circuit was accomplished, the second metal-oxide-semiconductor Q2 closed, and no current flows through on the 6th resistance R 6, does not also produce extra power consumption subsequently.Therefore the complete machine power-supply system can accomplish to start fast and get into operating state.When power-supply system breaks down like output short-circuit, the secondary coil Ns of the transformer T2 drops that powers on, the voltage of the feedback coil Naux of transformer T2 also descends thereupon, the VCC end of IC chip noenergy source again after work, the IC chip gets into stopped status.Reach the effect of protection power-supply system.

Claims

1. switching power circuit; Comprise current rectifying and wave filtering circuit; Power management IC chip is characterized in that: also comprise the fast protective circuit that rises, this input that plays protective circuit soon links to each other with rectification filter circuit output end; The output that should play protective circuit soon links to each other with the VCC feeder ear of power management IC chip, thereby makes the VCC feeder ear quick charge of power management IC chip.

2. switching power circuit according to claim 1; It is characterized in that: said fast protective circuit comprises first resistance, second resistance, the 3rd resistance, the 4th resistance, the 5th resistance, the 6th resistance, first electric capacity, second electric capacity, first voltage stabilizing didoe, first triode, second metal-oxide-semiconductor; The cathode output end of the first termination current rectifying and wave filtering circuit of first resistance wherein; Second end of first resistance links to each other with first end of second resistance; Second end of second resistance links to each other with first end of the 3rd resistance, the cathode output end of the second termination current rectifying and wave filtering circuit of the 3rd resistance, first electric capacity and the parallelly connected formation of the 3rd resistance delay circuit; First end of the 4th resistance links to each other with the cathode output end of current rectifying and wave filtering circuit; Second end of the 4th resistance links to each other with the emitter of first triode; The base stage of first triode links to each other with second end of second resistance, and the emitter of first triode links to each other with the cathode output end of current rectifying and wave filtering circuit; The two ends of the 5th resistance link to each other with the collector and emitter of first triode respectively; The anode of first voltage stabilizing didoe links to each other with the cathode output end of current rectifying and wave filtering circuit, and the negative electrode of first voltage stabilizing didoe links to each other with the collector electrode of first triode; The two ends of second electric capacity link to each other with the two ends of the 5th resistance respectively; The 6th resistance first end links to each other with the cathode output end of current rectifying and wave filtering circuit; Second end of the 6th resistance is connected with the drain electrode of second metal-oxide-semiconductor; The source electrode of second metal-oxide-semiconductor connects the VCC end of power management IC chip, and the grid of second metal-oxide-semiconductor links to each other with the collector electrode of first triode.