CN105305816A

CN105305816A - Method for realizing circuit control by adopting series connection of field-effect tubes

Info

Publication number: CN105305816A
Application number: CN201510754849.2A
Authority: CN
Inventors: 俞峰; 杨麒麟
Original assignee: Scud Fujian Electronic Co ltd
Current assignee: Scud Fujian Electronic Co ltd
Priority date: 2015-11-09
Filing date: 2015-11-09
Publication date: 2016-02-03

Abstract

The invention discloses a method for realizing circuit control by adopting series connection of a plurality of field-effect tubes. The method comprises more than two voltage withstand circuits and synchronous drive circuits, every two adjacent voltage withstand circuits are connected in series, and the structures of all the voltage withstand circuits are the same; each voltage withstand circuit comprises a field-effect tube, a resistor and a capacitor which are connected in parallel mutually; the field-effect tubes are connected with the synchronous drive circuits, and the synchronous drive circuits control the field-effect tubes to be connected or disconnected at the same time; the method is used by adopting series connection of the field-effect tubes, and simultaneously the resistor and the capacitor are adopted in each voltage withstand circuit, so that the voltage distributed by the field-effect tubes is average voltage of controlled circuits, and on-off control higher than the voltage withstand circuit of single field-effect tube is realized. Synchronous control is performed after series connection of the field-effect tubes is adopted, the on-off of voltage circuit exceeding the voltage circuits of the field-effect tubes can be controlled, and the method has the advantages of low temperature rise, low drive current, long service life, small size and low cost.

Description

A kind of method adopting multiple field effect transistor series connection realizing circuit to control

Technical field

The present invention relates to the power circuit field of electronic product, refer more particularly to a kind of method adopting multiple field effect transistor series connection realizing circuit to control.

Background technology

In electron trade, in many power supply products, all required power type electronic devices and components come conducting on realizing circuit or shutoff as electronic switch, this kind of electronic switch mainly contains relay, field effect transistor, IGBT, a few class such as triode, for more than in the high-current supply control circui of 300V high pressure, not withstand voltage due to field effect transistor, majority can adopt IGBT or relay to control etc., relay is wherein that mechanical system controls, there is operate time slow, driving power consumption is large, quiescent current is large, the features such as contact can cause the life-span short because of arcing wearing and tearing, IGBT and triode then on-state voltage drop are larger, in big current situation, power tube temperature rise is very high, need the cooling measure of relatively high power.

The break-make that existing field effect transistor carries out electronic circuit controls, generally be only applicable to the application scenario of low pressure applications occasion or high voltage-small current control, when voltage reaches more than 300V, when electric current is more than 50A, on market, existing field effect transistor cannot use not due to withstand voltage, IGBT or triode or relay can only be selected to control, and the temperature rise that IGBT or triode produce is very high, the high heat of 150W will be produced under such as 50A current conditions, the cost of relay is very high, it is mechanical contact, have high-voltage arc discharge wearing and tearing, useful life is short, drive current needs again very large, quiescent dissipation is also very large, volume is also large, cause there is certain limitation in actual applications.

Summary of the invention

The object of the invention is to overcome above-mentioned weak point of the prior art and employing that is long, low cost of a kind of life-span multiple field effect transistor series connection method that realizing circuit controls is provided.

The present invention realizes in the following way:

The method adopting multiple field effect transistor series connection realizing circuit to control, is characterized in that: comprise the voltage holding circuit of more than two, synchronous drive circuit, be in series, and the structure of all voltage holding circuits is all identical between two adjacent between two voltage holding circuits; Described voltage holding circuit comprises field effect transistor, resistance, electric capacity, parallel with one another between described field effect transistor, resistance, electric capacity; Described field effect transistor is connected with synchronous drive circuit, and synchronous drive circuit controls the conducting simultaneously of multiple field effect transistor or shutoff; This method adopts multiple field effect transistor to connect and uses, and adopt resistance and electric capacity to make the voltage assigned by field effect transistor for the average voltage of controlled circuit in each voltage holding circuit, the break-make achieved higher than the withstand voltage circuit of single field effect transistor controls simultaneously.

Beneficial effect of the present invention is: adopt multiple field effect transistor to connect and use, adopt resistance and electric capacity to make the voltage assigned by field effect transistor for the average voltage of controlled circuit in each voltage holding circuit, the break-make achieved higher than the withstand voltage circuit of single field effect transistor controls simultaneously.

Accompanying drawing explanation

Fig. 1 embodiment of the present invention schematic diagram.

Embodiment

Now by reference to the accompanying drawings, the specific embodiment of the invention is described in detail in detail:

The method adopting multiple field effect transistor series connection realizing circuit to control, comprises the voltage holding circuit of more than two, synchronous drive circuit, be in series, and the structure of all voltage holding circuits is all identical between two adjacent between two voltage holding circuits; Voltage holding circuit comprises field effect transistor, resistance, electric capacity, parallel with one another between field effect transistor, resistance, electric capacity; Field effect transistor is connected with synchronous drive circuit, and synchronous drive circuit controls the conducting simultaneously of multiple field effect transistor or shutoff; This method adopts multiple field effect transistor to connect and uses, and adopt resistance and electric capacity to make the voltage assigned by field effect transistor for the average voltage of controlled circuit in each voltage holding circuit, the break-make achieved higher than the withstand voltage circuit of single field effect transistor controls simultaneously.

Embodiment

As shown in Figure 1, the control circui of 500V is realized: two voltage holding circuits are connected mutually for the field effect transistor that 2 300V are withstand voltage, field effect transistor in two voltage holding circuits is connected with synchronous drive circuit respectively, and synchronous drive circuit controls the conducting simultaneously of two field effect transistor or shutoff;

After in parallel with an a resistance R and electric capacity C between the DS pole of each field effect transistor (MOSFET), connect between field effect transistor (MOSFET) again, the G pole of all field effect transistor (MOSFET) all drives by synchronous drive circuit, synchronous drive circuit, just refer to that the G pole of all field effect transistor (MOSFET) drives to carry out simultaneously, to each field effect transistor (MOSFET) be carry out simultaneously conducting driving or turn off drive, because the electric capacity C of two in circuit is identical parameter value, two resistance R are also identical parameter values, and the driving of field effect transistor (MOSFET) is simultaneously, therefore when (MOSFET) conducting of whole circuit loop scene effect pipe or shutoff, the voltage that each field effect transistor (MOSFET) is born can be uniform distribution, thus make whole circuit when turning off the withstand voltage that can bear close to withstand voltage 2 times of each field effect transistor (MOSFET), such as, when single field effect transistor (MOSFET) withstand voltage is 300V, after adopting 2 field effect transistor (MOSFET) series connection, the voltage that circuit controls can reach more than 500V.

When adopting the field effect transistor (MOSFET) of N number of more than 300V to carry out series connection control, the voltage that circuit controls can reach N*300V*0.85 (note: the unbalanced coefficient of the voltage averaged timing that the 0.85 parameter error value that is electric capacity and resistance and field effect transistor (MOSFET) junction capacitance causes), such as adopt 3 withstand voltage be 300V MOSFET connect, the voltage that circuit controls can reach more than 750V.

At present, high voltage bearing IGBT or triode are in the loop of 50A electric current, and the pressure drop that IGBT or triode produce can reach 3V, and the thermal power of generation has 50A*3V=150W.And adopting the circuit in the application, On-resistance can drop to and only has 0.02 Ω, and equally under 50A current conditions, pressure drop only has 1V, and the thermal power of generation only has 50W.This circuit is according to Control, and drive current can reach 120mA, and bulky, and keep static power consumption stream during adhesive also large, can reach more than 50mA, operate time needs 4mS; And if adopt the circuit in this patent, drive current and static power consumption stream can be reduced to 0.1mA, and operate time is within 0.02mS, and volume is very little.

Claims

1. the method adopting multiple field effect transistor series connection realizing circuit to control, is characterized in that: comprise the voltage holding circuit of more than two, synchronous drive circuit, be in series, and the structure of all voltage holding circuits is all identical between two adjacent between two voltage holding circuits; Described voltage holding circuit comprises field effect transistor, resistance, electric capacity, parallel with one another between described field effect transistor, resistance, electric capacity; Described field effect transistor is connected with synchronous drive circuit, and synchronous drive circuit controls the conducting simultaneously of multiple field effect transistor or shutoff; This method adopts multiple field effect transistor to connect and uses, and adopt resistance and electric capacity to make the voltage assigned by field effect transistor for the average voltage of controlled circuit in each voltage holding circuit, the break-make achieved higher than the withstand voltage circuit of single field effect transistor controls simultaneously.