CN202142981U

CN202142981U - Circuit for AC/DC switch power supply converter high-voltage starting

Info

Publication number: CN202142981U
Application number: CN201120265803U
Authority: CN
Inventors: 丁国华; 吴霖; 谭在超; 胡斌; 吴建国; 朱勤为; 李盼盼
Original assignee: WUXI SI-POWER MICRO-ELECTRONICS Co Ltd
Current assignee: WUXI SI-POWER MICRO-ELECTRONICS Co Ltd
Priority date: 2011-07-26
Filing date: 2011-07-26
Publication date: 2012-02-08
Anticipated expiration: 2021-07-26

Abstract

The present utility model provides a circuit for AC/DC switch power supply converter high-voltage starting. The circuit comprises a PWM controller which comprises a high-voltage starting module, an under-voltage locking module and a PWM generator. A power supply voltage pin of the PWM controller is connected with the cathode of a diode and connected with the ground through a high-voltage starting capacitor, the anode of the diode is connected with one end of a second secondary winding of the AC/DC switch power supply converter, and the other end of the second secondary winding is connected with the ground. One end of a primary winding of the AC/DC switch power supply converter is connected with the DC input high voltage, the other end is connected with a power switch leakage electrode, a power switch source electrode is connected with the ground, a drain electrode is connected with the output end of the PWM generator, and a first secondary winding of the AC/DC switch power supply converter is connected with a load. When the PWM controller is started, the charging current of the capacitor is cut off, the charging current of the capacitor can be freely adjusted through arranging resistors, and the charging current of the capacitor can be stabilized through the negative feedback technology.

Description

The circuit that is used for AC/DC switching power converters high voltage startup

Technical field

The utility model relates to a kind of integrated circuit, especially a kind of circuit that is used for AC/DC switching power converters high voltage startup.

Background technology

Supply convertor is widely used in the portable electric appts, supply convertor can be with power supply from a kind of formal argument to another kind of form.For example: power supply can transform to direct current (DC), transform to AC or transform to DC from DC from DC from exchanging (AC), and supply convertor comprises linear quantizer and two kinds of main types of switched-mode converter, and the utility model relates to switched-mode converter.

Fig. 1 is the rough schematic view of an AC/DC switching power converters topology; As shown in Figure 1; AC-input voltage is through converting direct current input high pressure 121 to behind the rectifying and wave-filtering; Generally require the AC/DC switching power converters can operate as normal in the 265VAC scope at AC-input voltage 85VAC, the corresponding direct voltage scope of this alternating voltage scope be 120VDC to 375VDC, i.e. the voltage range of direct current input high pressure 121 is that 120V is to 375V.

During circuit start, PWM controller 100 is not started working, and the output port 124 of PWM controller is a low level, so power switch 106 turn-offs.DC input voitage 121 charges through 107 pairs of electric capacity 104 of resistance; Along with the voltage on the electric capacity 104 rises, the voltage of the supply voltage input port VDD of PWM controller 100 also rises, when the voltage of VDD rises to when PWM controller 100 is started working; The output port 124 output PWM modulation signals of PWM controller 100; The conducting and the shutoff of control NMOS power tube 106, during 106 conductings of NMOS power tube, energy storage is in the elementary winding 101 of transformer; When NMOS power tube 106 ends; NE BY ENERGY TRANSFER is given first, second

secondary winding

102 and 103 of converter, and wherein first secondary winding 102 is for load provides energy, and second subprime winding 103 provides the work energy needed through diode 105 and electric capacity 104 for the PWM controller.

After PWM controller 100 operate as normal, its work energy needed is provided by transformer second subprime winding 103, but owing to can't cut off the path over the ground of resistance 107, can have leakage current always, causes power loss, has reduced the overall efficiency of AC/DC.The value of resistance 107 is big more, and after circuit start was accomplished, the power of loss was just more little on resistance 107; After but the value of resistance 107 is too big; Can cause when starting too for a short time to the charging current of electric capacity 104, the rate of voltage rise on the electric capacity 104 is slack-off, finally makes the AC/DC complete machine prolong start-up time.Otherwise the value of resistance 107 is got little, though can shorten AC/DC complete machine start-up time, the power of loss also increases thereupon.

Therefore, be starved of a kind of system and method for high voltage startup, the contact between said system start-up time and the system effectiveness is kept apart, can when improving system effectiveness, not influence the system start-up time.

Summary of the invention

The purpose of the utility model is to overcome the deficiency that exists in the prior art, and a kind of circuit of the AC/DC of being used for switching power converters high voltage startup is provided.

The technical scheme that provides according to the utility model; The said circuit that is used for AC/DC switching power converters high voltage startup; Comprise the PWM controller; Said PWM controller comprises high voltage startup module, under-voltage locking module and PWM generator, and the input of said high voltage startup module connects direct current input high pressure, and the high voltage startup module also connects the input of PWM generator; The supply voltage pin of PWM controller connects the input of PWM generator and the input of under-voltage locking module, the input of the output termination PWM generator of under-voltage locking module and the input of high voltage startup module; Through the high voltage startup capacity earth, diode anode connect an end of the second subprime winding of AC/DC switching power converters, the second subprime winding other end ground connection when supply voltage pin of PWM controller connected diode cathode; The elementary winding one termination direct current input high pressure of AC/DC switching power converters, another termination power switch drain electrode, power switch source ground, grid connect the output of PWM generator; First secondary winding of AC/DC switching power converters connects load.

Said high voltage startup module comprises: the drain electrode of technotron connects direct current input high pressure, and the grounded-grid of technotron, source electrode connect an end and first nmos transistor drain of first resistance; The grid of first nmos pass transistor connects the other end of first resistance, and source electrode connects an end of the transistorized source electrode of PMOS and second resistance, the other end of the transistorized grid connecting resistance of PMOS and the supply voltage pin of PWM controller; The PMOS transistor drain connects the drain and gate of second nmos pass transistor; Second nmos pass transistor links to each other source ground with the 3rd nmos pass transistor grid; The drain electrode of the 3rd nmos pass transistor connects the drain electrode of the grid and the 4th nmos pass transistor of first nmos pass transistor; The grid of nmos pass transistor connects the high-level control signal of under-voltage locking module output.

The high voltage startup module produces one road current signal, and high voltage startup electric capacity is charged, and As time goes on, voltage can increase on the high voltage startup electric capacity; The under-voltage locking module is being monitored the variation of voltage on the high voltage startup electric capacity constantly; When the voltage on the high voltage startup electric capacity surpasses certain threshold voltage; The output control signal; This control signal is given PWM generator and is produced modulation signal, also gives the high voltage startup module simultaneously and is used for cutting off the charging current to high voltage startup electric capacity.In the high voltage startup module, the utility model is used for stablizing the charging current to high voltage startup electric capacity for it has designed a negative-feedback circuit, makes this charging current and direct current input high pressure irrelevant.

The utility model has the advantages that: the utility model carries out technological improvement to existing high-voltage starting circuit; After the PWM controller is accomplished startup; Cut-out is to the charging current of electric capacity; Through be provided with resistance can free adjustment to the charging current of electric capacity, and introduce negative-feedback technology and be used for stable charging current electric capacity.

Description of drawings

Fig. 1 is the prior art circuits principle schematic;

Fig. 2 is the utility model circuit block diagram;

Fig. 3 is the circuit theory diagrams of the high voltage startup module of the utility model embodiment.

Embodiment

Below in conjunction with accompanying drawing and embodiment the utility model is described further.The utility model only is that the mode with example is applied in the AC/DC switching power converters, but will be appreciated that and the utlity model has wide applications more.

As shown in Figure 2; The utility model comprises PWM controller 100; Said PWM controller 100 comprises high voltage startup module 207, under-voltage locking module 208 and PWM generator 209; The input of said high voltage startup module 207 connects direct current input high pressure 121; High voltage startup module 207 also connects the input of PWM generator 209, and the supply voltage pin VDD of PWM controller 100 connects the input of PWM generator 209 and the input of under-voltage locking module 208, the input of the output termination PWM generator 209 of under-voltage locking module 208 and the input of high voltage startup module 207; When connecting diode 204 negative electrodes, passes through the supply voltage pin VDD of PWM controller 100 high voltage startup electric capacity 204 ground connection; Diode 204 anodes connect an end of the second subprime winding 103 of AC/DC switching power converters, second subprime winding 103 other end ground connection; The elementary winding 101 1 termination direct currents input high pressure 121 of AC/DC switching power converters, another termination power switch 106 drain electrodes, power switch 106 source grounds, grid connects the output of PWM generator 209; First secondary winding 102 of AC/DC switching power converters connects load.

High voltage startup module 207 is configured and is used for accepting direct current input high pressure and control signal, and produces one road current signal, and this current signal charges to electric capacity, converts voltage signal to; Under-voltage locking module 208 is configured to accept above-mentioned voltage signal and produces control signal; PWM generator 209 is configured to accept above-mentioned voltage signal and above-mentioned control signal, and produces modulation signal; Power switch 106 is configured to accept the input current of above-mentioned modulation signal and control switching converter.

During the system electrifying startup, the output port output low level of PWM controller 100, power switch 106 turn-offs, and does not have NE BY ENERGY TRANSFER on the Transformer Winding, so voltage is zero on the high voltage startup electric capacity 204.Direct current input high pressure 121 is input on the high voltage startup module 207 through the pin HV of PWM controller 100; The high voltage startup module will be imported high pressure and convert a constant electric current to, and high voltage startup electric capacity 204 is charged, and As time goes on the voltage on the electric capacity 204 rise; Be that voltage on the supply voltage pin VDD of PWM controller 100 rises; Above-mentioned voltage is that PWM controller 100 provides supply voltage, and when this voltage surpassed certain pre-set threshold voltage, under-voltage locking module 208 output control signals were given PWM generator 209 and high voltage startup module 207; Export modulation signal after the PWM generator 209 suspension control signal effects; Power switch 106 is accepted this modulation signal, and transformer begins to transmit energy, and Secondary winding of transformer 103 begins for PWM controller 100 the work energy needed to be provided.After the 207 suspension control signal effects of high voltage startup module, cut off charging current to high voltage startup electric capacity 204.

As shown in Figure 3, high voltage startup module 207 comprises: direct current input high pressure is applied to the drain electrode of technotron 302, and the grounded-grid of technotron 302, source electrode connect an end and 304 drain electrodes of first nmos pass transistor of first resistance 303; The grid of first nmos pass transistor 304 connects the other end of first resistance 303, and source electrode meets the source electrode of PMOS transistor 306 and an end of second resistance 303, the supply voltage pin VDD of the other end of the grid connecting resistance 305 of PMOS transistor 306 and PWM controller 100; The drain electrode of PMOS transistor 306 connects the drain and gate of second nmos pass transistor 308; Second nmos pass transistor 308 links to each other source ground with the 3rd nmos pass transistor 309 grids; The drain electrode of the 3rd nmos pass transistor 309 connects the drain electrode of the grid and the 4th nmos pass transistor 310 of first nmos pass transistor 304; The grid of nmos pass transistor 310 connects the high-level control signal 311 of under-voltage locking module output.

The operation principle of the utility model is that when system powered on, the supply voltage VDD of PWM controller was zero, under-voltage locking module 208 output low levels, 310 shutoffs of the 4th nmos pass transistor.Increase along with direct current input high pressure; The source voltage 312 of technotron 302 is also followed rising; After voltage 312 rises to the grid voltage that makes first nmos pass transistor 304 and surpasses its threshold voltage conducting; Electric current flows out from the source electrode of first nmos pass transistor 304, gives high voltage startup electric capacity 204 chargings through second resistance, 305 backs.Along with the electric current of second resistance 305 of flowing through increases, 306 conductings of PMOS transistor produce electric current, in case after 306 conductings of PMOS transistor, the charging current of high voltage startup electric capacity 204 just is stabilized in V _GS306/ R ₃₀₅, work as V _GS306During variation, the feedback loop that designs in the circuit can suppress it to be changed, thus stable charging current to high voltage startup electric capacity.

The feedback loop operation principle is to work as V _GS306During increase, I _DS306Can increase, make the drain-source current of second nmos pass transistor 308 increase, second nmos pass transistor 308 must increase its gate source voltage in order to adapt to the increase of electric current, causes the gate source voltage of the 3rd nmos pass transistor 309 to increase.V _GS309Increase, can cause I equally _DS309Increase, this electric current is through first resistance 303, and therefore the pressure drop on first resistance 303 increases, and causes the grid voltage of first nmos pass transistor 304 to descend, and the source voltage of first nmos pass transistor 304 is followed its grid voltage and descended, and finally makes V _GS306Reduce, accomplish a negative feedback control procedure.Wherein, V, I, R represent voltage, electric current, the resistance of the components and parts that its index number is identified in the accompanying drawings respectively.

When under-voltage locking module 208 detects voltage on the high voltage startup electric capacity 204 and surpasses its threshold value that designs in advance; Under-voltage locking module output high-level control signal 311; 310 conductings of control signal 311 control nmos pass transistors; Nmos pass transistor 304 grids pulled down to ground and turn-off, and have cut off the charging current to high voltage startup electric capacity 204.

At this moment, the flow through electric current of first resistance 303 is V ₃₁₂/ R ₃₀₃, in direct current input high pressure uphill process, the voltage at 312 places can not followed its rising always; Because the grounded-grid of technotron; Along with the continuous rising of HV voltage, pinch off can take place in its conducting channel, and therefore the voltage at 312 places is stabilized near the pinch-off voltage of technotron 302.Start the quiescent current that high-voltage starting circuit consumed after electric capacity 204 charging currents in order to reduce cutoff high; First resistance, 303 general values are bigger; For example during value 10M ohm, the quiescent current that the high voltage startup electric current is consumed is a microampere rank, has significantly reduced system's quiescent dissipation.

Use the high-voltage starting circuit that the utility model proposed, can effectively reduce the quiescent current of switch power supply system after accomplishing high voltage startup, improve overall efficiency.And can be provided with through resistance the charging current of high voltage startup electric capacity 204, this electric current can be realized stablizing under the effect of negative-feedback circuit.

Claims

1. the circuit that is used for AC/DC switching power converters high voltage startup; Comprise PWM controller (100); It is characterized in that: said PWM controller (100) comprises high voltage startup module (207), under-voltage locking module (208) and PWM generator (209); The input of said high voltage startup module (207) connects direct current input high pressure (121); High voltage startup module (207) also connects the input of PWM generator (209); The supply voltage pin (VDD) of PWM controller (100) connects the input of PWM generator (209) and the input of under-voltage locking module (208), the input of the output termination PWM generator (209) of under-voltage locking module (208) and the input of high voltage startup module (207); When connecting diode (204) negative electrode, passes through the supply voltage pin (VDD) of PWM controller (100) high voltage startup electric capacity (204) ground connection; Diode (204) anode connects an end of the second subprime winding (103) of AC/DC switching power converters, second subprime winding (103) other end ground connection; Elementary winding (101) the one termination direct currents input high pressure (121) of AC/DC switching power converters, another termination power switch (106) drain electrode, power switch (106) source ground, grid connects the output of PWM generator (209); First secondary winding (102) of AC/DC switching power converters connects load.

2. the circuit that is used for AC/DC switching power converters high voltage startup according to claim 1; It is characterized in that said high voltage startup module (207) comprising: the drain electrode of technotron (302) connects direct current input high pressure; The grounded-grid of technotron (302), source electrode connect an end and first nmos pass transistor (304) drain electrode of first resistance (303); The grid of first nmos pass transistor (304) connects the other end of first resistance (303); Source electrode connects the source electrode of PMOS transistor (306) and an end of second resistance (303), the other end of the grid connecting resistance (305) of PMOS transistor (306) and the supply voltage pin (VDD) of PWM controller (100); The drain electrode of PMOS transistor (306) connects the drain and gate of second nmos pass transistor (308); Second nmos pass transistor (308) links to each other source ground with the 3rd nmos pass transistor (309) grid; The drain electrode of the 3rd nmos pass transistor (309) connects the drain electrode of the grid and the 4th nmos pass transistor (310) of first nmos pass transistor (304); The grid of nmos pass transistor (310) connects the high-level control signal (311) of under-voltage locking module output.