CN201966801U

CN201966801U - Voltage resistance circuit

Info

Publication number: CN201966801U
Application number: CN2011200451686U
Authority: CN
Inventors: 吴新科; 华桂潮; 王莉
Original assignee: Inventronics Hangzhou Co Ltd
Current assignee: Led One Hangzhou Co Ltd
Priority date: 2011-02-23
Filing date: 2011-02-23
Publication date: 2011-09-07
Anticipated expiration: 2021-02-23

Abstract

The utility model discloses a voltage resistance circuit, which comprises a first switching tube, a second switching tube and an auxiliary capacitor, wherein a source electrode of the second switching tube is connected with a drain electrode of the first switching tube; a grid electrode of the second switching tube is connected with an auxiliary power supply through a reversely connected diode; a grid electrode of the first switching tube is used for receiving a driving voltage; the source electrode of the first switching tube is connected with the grid electrode of the second switching tube through a first voltage-regulator diode; and the auxiliary capacitor comprises a first capacitor and/or a second capacitor, wherein the first capacitor is connected in parallel with the diode, and/or the second capacitor is connected in parallel with the voltage-regulator diode. The voltage resistance circuit disclosed by the utility model has a simple structure. Enough driving voltage and current are supplied to the second switching tube by the power supply Vcc (volt current condenser) through the diode, and thereby, the breakover speed of the second switching tube is accelerated and the circuit efficiency is improved.

Description

A kind of voltage holding circuit

Technical field

The utility model relates to the electric equipment field, relates in particular to a kind of voltage holding circuit.

Background technology

For the higher occasion of line voltage, for example the 480VAC electrical network designs the Switching Power Supply that is suitable for and can run into the problem that the high-voltage transistor switching device is chosen difficulty.For the 480VAC electrical network, consider the fluctuation and the design capacity of electrical network, use traditional Switching Power Supply scheme need select for use the above transistor of withstand voltage 1000V as switching device usually, the above transistor of withstand voltage 1000V belongs to relatively special device, and procurement cycle is long, price is high.In order to address the above problem, prior art adopts following scheme:

Fig. 1 is that two metal-oxide-semiconductor series connection improve the application of device withstand voltage at circuit of reversed excitation.Manage Q1 down and be subjected to the direct driving of pwm control circuit, when Q1 by becoming from conducting when turn-offing, the DS both end voltage of Q1 raises, when the DS of Q1 both end voltage during near voltage-stabiliser tube ZD1 voltage, the GS voltage of last pipe Q2 is lower than the conducting threshold voltage, Q2 also enters off state, and the voltage that Q1 shared when Q1, Q2 turn-offed is by the voltage stabilizing value decision of voltage-stabiliser tube ZD1.The DS both end voltage descends when Q1 transfers conducting to by shutoff, and resistance R 1 will make also conducting of Q2 for Q2 provides drive current.But, because R1 is subjected to the restriction of oneself power consumption, can not when the Q2 conducting, provide bigger drive current, make the conducting speed of Q2 slow, the switching loss of Q2 and conduction loss are all bigger, so this circuit efficiency is low, only are applicable to the occasion that power is very little usually.

The utility model content

In view of this, the utility model provides a kind of voltage holding circuit, has solved the problem of voltage holding circuit of the prior art.Its concrete scheme is as follows:

A kind of voltage holding circuit comprises: first switching tube, second switch pipe and auxiliary capacitor;

The source electrode of described second switch pipe links to each other with the drain electrode of described first switch; The grid of described second switch pipe links to each other with accessory power supply by the diode of reversal connection; The grid of described first switching tube receives driving voltage, and the source electrode of described first switching tube links to each other with the grid of described second switch pipe by first voltage stabilizing didoe; Described auxiliary capacitor comprises: first electric capacity in parallel with described diode and/or second electric capacity in parallel with described voltage stabilizing didoe.

Preferably, also comprise clamp circuit, the cold end of described clamp circuit links to each other with the source electrode of described second switch pipe, and the hot end of described clamp circuit links to each other with the grid of described second switch pipe.

Preferably, described clamp circuit is second voltage stabilizing didoe.

Preferably, described first switching tube and described second switch pipe are field effect transistor MOSFET or insulated gate bipolar transistor IGBT.

By such scheme as can be seen, the disclosed voltage holding circuit of the utility model is simple in structure, accessory power supply Vcc provides enough driving voltage and electric currents through diode to the second switch pipe, access by auxiliary capacitor, make the second switch pipe reduce with respect to the switch time-delay of first switching tube, can further reduce the wastage, improve the efficient and the reliability of circuit.

Description of drawings

In order to be illustrated more clearly in the utility model embodiment or technical scheme of the prior art, to do to introduce simply to the accompanying drawing of required use in embodiment or the description of the Prior Art below, apparently, accompanying drawing in describing below only is embodiment more of the present utility model, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is the application structure schematic diagram of voltage holding circuit in circuit of reversed excitation of prior art;

Fig. 2 is the structural representation of the disclosed voltage holding circuit of the utility model embodiment;

Fig. 3 is the principle schematic of the disclosed voltage holding circuit of the utility model embodiment;

Fig. 4 is the structural representation of the disclosed another voltage holding circuit of the utility model embodiment;

Fig. 5 is the structural representation of the disclosed circuit of reversed excitation of the utility model embodiment;

Fig. 6 is the structural representation of the disclosed BUCK circuit of the utility model embodiment;

Fig. 7 is the structural representation of the disclosed BOOST circuit of the utility model embodiment.

Embodiment

Below in conjunction with the accompanying drawing among the utility model embodiment, the technical scheme among the utility model embodiment is clearly and completely described, obviously, described embodiment only is the utility model part embodiment, rather than whole embodiment.Based on the embodiment in the utility model, those of ordinary skills are not making the every other embodiment that is obtained under the creative work prerequisite, all belong to the scope of the utility model protection.

The utility model discloses a kind of voltage holding circuit, its structure comprises as shown in Figure 2: the first switching tube Q1, second switch pipe Q2 and auxiliary capacitor, and wherein: the source electrode of second switch pipe Q2 links to each other with the drain electrode of the first switch Q1; The grid of second switch pipe Q2 links to each other with accessory power supply Vcc by the diode D1 of reversal connection; The grid of the described first switching tube Q1 receives driving voltage, and the source electrode of the first switching tube Q1 links to each other with the grid of second switch pipe Q2 by the first voltage stabilizing didoe ZD1.

Auxiliary capacitor in the present embodiment comprises: first capacitor C 1 in parallel with diode D1 and second capacitor C 2 in parallel with the first voltage stabilizing didoe ZD1.

The schematic diagram of the operation principle of the disclosed voltage holding circuit of present embodiment is as shown in Figure 3:

When the first switching tube Q1, second switch pipe Q2 are in conducting state, at this moment second switch pipe Q2 grid G 2 approaches the accessory power supply voltage vcc with the voltage VGS2 of source S 2 point-to-point transmissions.When the first switching tube Q1 begins to turn-off under the effect of drive signal Vd, the drain D 1 of the Q1 of first switch raises with the voltage VDS1 of source S 1 point-to-point transmission, diode D1 bears back-pressure and turn-offs, an electric current part that meanwhile flows through second switch pipe Q2 flows through the first switching tube Q1, another part is given first capacitor C 1 and 2 chargings of second capacitor C through the grid source electrode parasitic capacitance Cgs2 of second switch pipe Q2, the grid voltage VG2 of the source voltage VS2 of second switch pipe Q2, second switch pipe Q2 rises, and voltage VGS2 descends between source electrode and grid.As the grid voltage VG2 of second switch pipe Q2 during near the voltage stabilizing value of voltage-stabiliser tube ZD1, VGS2 reduces rapidly that Q2 also enters off state behind the conducting threshold voltage that is lower than Q2.The first switching tube Q1, when second switch pipe Q2 turn-offs the DS both end voltage of Q1 by the decision of the voltage stabilizing value of the first voltage stabilizing didoe ZD1.

Suppose that the first switching tube Q1, second switch pipe Q2 all are in off state, second switch pipe Q2 grid G 2 approaches 0V with the voltage VGS2 of source S 2 point-to-point transmissions, and second switch pipe Q2 grid voltage VG2, second switch pipe Q2 source voltage VS2 approximate the voltage of voltage regulation of the first voltage stabilizing didoe ZD1.When beginning conducting under the high level driving action of the first switching tube Q1 at Vd, the voltage VDS1 that the drain D 1 of the first switching tube Q1 and source S are 1 descends, first capacitor C 1, second capacitor C 2 reduce second switch pipe Q2 grid voltage VG2 through grid source electrode parasitic capacitance Cgs2, the first switching tube Q1 discharge of second switch pipe Q2, source voltage VGS2 rises, when second switch pipe Q2 grid voltage VG2 is lower than Vcc, diode D1 conducting, Vcc provides enough driving voltage and electric currents through D1 to Q2, makes also conducting of second switch pipe Q2.

This shows that the disclosed voltage holding circuit of present embodiment is simple in structure, power Vcc provides enough driving voltage and electric currents through diode to the second switch pipe, has accelerated the conducting speed of second switch pipe, has improved circuit efficiency.Simultaneously, because first capacitor C 1, second capacitor C 2 have extracted the electric charge among the grid source electrode parasitic capacitance Cgs2 of second switch pipe Q2 in advance when the first switching tube Q1 turn-offs, VGS2 is descended fast, thereby quickened the shutoff of second switch pipe Q2; When opening, first capacitor C 1, second capacitor C 2 in advance to the grid source electrode parasitic capacitance Cgs2 charging of second switch pipe Q2, make the VGS2 fast rise, thereby have also quickened the open-minded of second switch pipe Q2 again.As can be seen, the existence of first capacitor C 1 and second capacitor C 2 makes second switch pipe Q2 reduce with respect to the switching time delay of the first switching tube Q1, can further reduce the wastage, and improves the efficient and the reliability of circuit.

Present embodiment does not limit the mode that adds first electric capacity and second electric capacity simultaneously, can also be chosen in the mode of diode or voltage stabilizing didoe two ends shunt capacitance, just adopt the mode of two electric capacity to adopt the mode of an electric capacity can further reduce the switch time-delay, improve circuit efficiency.

First switching tube in the present embodiment and second switch pipe are field-effect transistor MOSFET or insulated gate polar form power tube IGBT, do not limit its particular type herein.

Further, in the voltage holding circuit shown in Figure 2, can also comprise clamp circuit between the grid that is connected in parallel on second switch pipe Q2 and the source electrode, as shown in Figure 5, in the present embodiment, clamp circuit is the second voltage stabilizing didoe ZD2.The grid voltage that guarantees second switch pipe Q2 is within safe range.

Further, the voltage holding circuit shown in above-mentioned Fig. 2 and Fig. 4 can be used as a switching device, is applied in other circuit, for example: circuit of reversed excitation, buck conversion BUCK circuit and BOOST booster circuit etc.

With circuit shown in Figure 2 is example, the structural representation of its composition circuit of reversed excitation as shown in Figure 5, it in the wire frame the disclosed voltage holding circuit of the utility model embodiment, its integral body is used as a switching device, the drain electrode of second switch pipe Q2 connects the end of the same name of the former limit winding of transformer T1, and the end of the same name of the secondary winding of transformer T1 connects output plus terminal by the second diode D2.Output capacitance Co in parallel between output plus terminal and the output negative terminal.

Wherein the widespread usage of circuit of reversed excitation is in Switching Power Supply, and its input voltage is Vin, and output voltage is Vo.If input voltage vin is bigger, just need the voltage endurance capability of switching tube stronger this moment, withstand voltage higher.And the disclosed voltage holding circuit of the utility model embodiment is as switching tube,

In like manner, the structure of the BUCK circuit of its composition as shown in Figure 6, the structure of the booster circuit BOOST of composition as shown in Figure 7, voltage holding circuit is applied in the foregoing circuit as switching device equally.

This shows that the disclosed voltage holding circuit of the utility model embodiment is applicable to the topological structure of multiple converter, the scope of application is wider.

Each embodiment adopts the mode of going forward one by one to describe in this specification, and what each embodiment stressed all is and the difference of other embodiment that identical similar part is mutually referring to getting final product between each embodiment.For the disclosed device of embodiment, because it is corresponding with the embodiment disclosed method, so description is fairly simple, relevant part partly illustrates referring to method and gets final product.

To the above-mentioned explanation of the disclosed embodiments, make this area professional and technical personnel can realize or use the utility model.Multiple modification to these embodiment will be conspicuous concerning those skilled in the art, and defined herein General Principle can realize under the situation that does not break away from spirit or scope of the present utility model in other embodiments.Therefore, the utility model will can not be restricted to these embodiment shown in this article, but will meet and principle disclosed herein and features of novelty the wideest corresponding to scope.

Claims

1. a voltage holding circuit is characterized in that, comprising: first switching tube, second switch pipe and auxiliary capacitor;

2. circuit according to claim 1 is characterized in that, also comprises clamp circuit, and the cold end of described clamp circuit links to each other with the source electrode of described second switch pipe, and the hot end of described clamp circuit links to each other with the grid of described second switch pipe.

3. circuit according to claim 2 is characterized in that, described clamp circuit is second voltage stabilizing didoe.

4. according to any described circuit among the claim 1-3, it is characterized in that described first switching tube and described second switch pipe are field effect transistor MOSFET or insulated gate bipolar transistor IGBT.