CN205232018U - Discrete component high frequency switch gate drive circuit - Google Patents

The utility model discloses a discrete component high frequency switch gate drive circuit relates to the drive circuit technical field, it includes drive signal module, level conversion module, pull -up drive module, drop -down drive module and switch tube, the drive signal module includes digital process chip or singlechip, and the drive signal module produces the PWM control signal by digital process chip or singlechip output, level conversion module connects in the drive signal module for carry out level conversion with the PWM signal, and pull -up drive module is given in output, pull -up drive module connects on level conversion module, and drop -down drive module connects in the drive signal module, and pull -up drive module, drop -down drive module are used for enlargeing of drive signal voltage and electric current, the switch tube is connected on pull -up drive module and drop -down drive module, the beneficial effects of the utility model are that: realize high frequency switch gate drive under little components and very low -cost condition, substitute gate drive IC, improved the product price / performance ratio.

Discrete component high frequency switch gate drive circuit

Technical Field

The utility model relates to a drive circuit, more specifically the utility model relates to a discrete component high frequency switch gate drive circuit.

Background

With the miniaturization and intellectualization of electronic products, the application of digital control power supplies is more and more extensive. The common simple digital power supply comprises an operation and control unit consisting of a DSP or a singlechip, a grid drive chip, a switching tube, an inductor and other elements. The digital control unit outputs a low-voltage high-internal resistance signal of about 5V, cannot be directly used for driving a switching tube, and needs a grid driving chip for conversion. The cost of the grid driving chip is high, and the cost performance of a low-power product is reduced.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome the not enough of above-mentioned technique, provide a discrete component high frequency switch gate drive circuit, this circuit structure is simple, with low costs, has improved the price/performance ratio of product.

The technical scheme of the utility model is realized like this: in a discrete component high frequency switching gate drive circuit, the improvement comprising: the device comprises a driving signal module, a level conversion module, a pull-up driving module, a pull-down driving module and a switching tube; wherein,

The driving signal module comprises a digital processing chip or a single chip microcomputer, and the driving signal module generates a PWM control signal output by the digital processing chip or the single chip microcomputer;

the level conversion module is connected to the driving signal module and used for carrying out level conversion on the PWM signal and outputting the PWM signal to the pull-up driving module;

the pull-up driving module is connected to the level conversion module, the pull-down driving module is connected to the driving signal module, and the pull-up driving module and the pull-down driving module are used for driving amplification of signal voltage and current;

the switch tube is connected to the pull-up driving module and the pull-down driving module.

In the structure, the level conversion module comprises an auxiliary power supply VCC, a fifth resistor and a third field effect transistor, the auxiliary power supply VCC is connected to the grid electrode of the third field effect transistor through the fifth resistor, and the PWM control signal pin of the digital processing chip or the single chip microcomputer is connected to the source electrode of the third field effect transistor.

Furthermore, an auxiliary power supply interface is arranged on a digital processing chip or a single chip microcomputer of the driving signal module, and the auxiliary power supply VCC is connected to the auxiliary power supply interface.

Furthermore, the pull-up driving module comprises a first triode, a second resistor, a fourth resistor, a sixth resistor and an auxiliary power supply for driving the switching tube, a source electrode of the third field effect tube is connected to a base electrode of the first triode through the sixth resistor, one path of the auxiliary power supply is connected to an emitting electrode of the first triode, the other path of the auxiliary power supply is connected to the base electrode of the first triode through the fourth resistor, and a collector electrode of the first triode outputs a pull-up driving signal through the second resistor.

Further, the voltage of the auxiliary power supply for driving the switching tube is 12V.

Furthermore, a second diode is arranged between the level conversion module and the pull-up driving module, and the second diode is arranged between the sixth resistor and the third field effect transistor.

In the structure, the pull-down driving module comprises a fourth field effect transistor, a seventh resistor and an eighth resistor, a PWM control signal pin of the digital processing chip or the single chip microcomputer is connected to a gate of the fourth field effect transistor through the eighth resistor, and a drain of the fourth field effect transistor outputs the pull-down driving signal through the seventh resistor.

In the above structure, the switching tube is a MOSFET or an IGBT.

In the above structure, it further includes a topology circuit, where the topology circuit includes a first diode, a first inductor, and a first capacitor, one end of the first diode is grounded, and the other end of the first diode is connected to the switch tube; one end of the first inductor is connected to the switching tube, and the other end of the first inductor is a voltage output end; one end of the first capacitor is connected to the voltage output end, and the other end of the first capacitor is grounded.

In the above structure, the feedback circuit further includes a feedback circuit, where the feedback circuit is composed of a third resistor, a ninth resistor, and a third capacitor, one end of the third resistor is connected to the voltage output end, the other end of the third resistor is connected to one end of the ninth resistor, a connection end between the third resistor and the ninth resistor is a common end, the other end of the ninth resistor is grounded, and the third capacitor is connected in parallel with the ninth resistor; and the common end of the third resistor and the ninth resistor is a feedback voltage output end, and the common end is electrically connected to a feedback signal input end of the digital processing chip or the singlechip.

The utility model has the advantages that: when the PWM signal output by the digital processing chip MCU is high, the voltage difference of the gate source electrode of the third field effect transistor is zero, the first triode is also cut off, and the second resistor has no voltage output; meanwhile, the high level enables the fourth field effect transistor to be conducted through the eighth resistor, the grid voltage of the second field effect transistor is pulled down through the seventh resistor and the fourth field effect transistor, and the second field effect transistor is cut off; when the PWM signal output by the digital processing chip MCU is low, the fourth field effect transistor is cut off; the third field effect transistor is conducted, the base electrode of the first triode is pulled down through the sixth resistor and the second diode, the collector electrode of the emitter of the first triode is conducted, high voltage is output through the second resistor, and the second field effect transistor is conducted; the utility model discloses this kind of discrete component high frequency switch gate drive circuit realizes the drive of high frequency switch gate under few components and very low cost condition, and replacement gate drive IC has improved product nature price ratio, and the product has good market prospect.

Drawings

Fig. 1 is a schematic block diagram of a discrete component high frequency switch gate driving circuit according to the present invention.

Fig. 2 is a diagram of an embodiment of a discrete component high frequency switch gate driver circuit according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, the utility model discloses a discrete component high frequency switch gate drive circuit, the utility model discloses a high frequency switch gate drive is realized to this kind of circuit structure under few components and very low-cost condition, has replaced gate drive IC, has improved the price/performance ratio of product. In the embodiment shown in fig. 1, the discrete component high-frequency switching gate driving circuit includes a driving signal module 10, a level converting module 20, a pull-up driving module 30, a pull-down driving module 40, and a switching tube 50, and the discrete component high-frequency switching gate driving circuit in this embodiment is described in detail below with reference to functions of the respective modules. The driving signal module 10 includes a digital processing chip or a single chip, and the driving signal module 10 generates a PWM (pulse width modulation) control signal output by the digital processing chip or the single chip; the level conversion module 20 is connected to the driving signal module 10, and is configured to perform level conversion on the PWM signal and output the PWM signal to the pull-up driving module 30; the pull-up driving module 30 is connected to the level shifting module 20, the pull-down driving module 40 is connected to the driving signal module 10, and the pull-up driving module 30 and the pull-down driving module 40 are used for amplifying driving signal voltage and current; the switching tube 50 is connected to the pull-up driving module 30 and the pull-down driving module 40.

As shown in fig. 2, a specific embodiment of the discrete component high-frequency switching gate driving circuit is shown, in this embodiment, the driving signal module 10, the level shifting module 20, the pull-up driving module 30, the pull-down driving module 40, and the switching tube 50 are described in detail. The level shift module 20 includes an auxiliary power VCC, a fifth resistor R5 and a third fet Q3, the auxiliary power VCC is connected to the gate of the third fet Q3 through the fifth resistor R5; in this embodiment, the driving signal module 10 includes a digital processing chip MCU, and a PWM control signal pin of the digital processing chip MCU is connected to the source of the third fet Q3. An auxiliary power supply interface is arranged on the digital processing chip MCU of the driving signal module 10, and the auxiliary power supply VCC is connected to the auxiliary power supply interface. The pull-up driving module 30 includes a first triode Q1, a second resistor R2, a fourth resistor R4, a sixth resistor R6 and an auxiliary power supply for driving the switching tube 50, a source of the third field effect transistor Q3 is connected to a base of the first triode Q1 through the sixth resistor R6, one path of the auxiliary power supply is connected to an emitter of the first triode Q1, the other path of the auxiliary power supply is connected to a base of the first triode Q1 through the fourth resistor R4, and a collector of the first triode Q1 outputs a pull-up driving signal through the second resistor R2. In this embodiment, as shown in fig. 2, the voltage of the auxiliary power supply for driving the switch tube 50 is 12V. In addition, a second diode D2 is disposed between the level shift module 20 and the pull-up driving module 30, and a second diode D2 is disposed between the sixth resistor R6 and the third fet Q3.

Further, the pull-down driving module 40 includes a fourth field effect transistor Q4, a seventh resistor R7 and an eighth resistor R8, the PWM control signal pin of the digital processing chip MCU is connected to the gate of the fourth field effect transistor Q4 through the eighth resistor R8, and the drain of the fourth field effect transistor Q4 outputs a pull-down driving signal through the seventh resistor R7. In this embodiment, the switch tube 50 is a MOSFET or an IGBT, but the switch tube 50 may be other types of power switches.

Further, in this embodiment, the discrete component high-frequency switch gate driving circuit further includes a feedback circuit, the feedback circuit is composed of a third resistor R3, a ninth resistor R9 and a third capacitor C3, one end of the third resistor R3 is connected to the voltage output end, the other end of the third resistor R3 is connected to one end of a ninth resistor R9, a connection end of the third resistor R3 and the ninth resistor R9 is a common end, the other end of the ninth resistor R9 is grounded, and the third capacitor C3 is connected in parallel with the ninth resistor R9; and the common end of the third resistor R3 and the ninth resistor R9 is a feedback voltage output end, and the common end is electrically connected to a feedback signal input end of the digital processing chip MCU. Furthermore, the discrete component high frequency switch gate driving circuit further comprises a topology circuit, the topology circuit comprises a first diode D1, a first inductor L1 and a first capacitor C1, one end of the first diode D1 is grounded, and the other end of the first diode D1 is connected to the switching tube 50; one end of the first inductor L1 is connected to the switching tube 50, and the other end of the first inductor L1 is a voltage output end; one end of the first capacitor C1 is connected to the voltage output end, and the other end of the first capacitor C1 is grounded.

With reference to fig. 2, we will describe the main operation principle of the discrete component high frequency switch gate driving circuit in the embodiment, when the PWM signal output by the digital processing chip MCU is high, the gate-source voltage difference of the third fet Q3 is zero, the first transistor Q1 is also turned off, and the second resistor R2 has no voltage output; meanwhile, the high level makes the fourth field effect transistor Q4 turned on through the eighth resistor R8, the gate voltage of the second field effect transistor Q2 is pulled low through the seventh resistor R7 and the fourth field effect transistor Q4, and the second field effect transistor Q2 is turned off. When the PWM signal output by the digital processing chip MCU is low, the fourth field effect transistor Q4 is cut off; the third field effect transistor Q3 is conducted, the base electrode of the first triode Q1 is pulled down through the sixth resistor R6 and the second diode D2, the collector electrode of the first triode Q1 is conducted, high voltage is output through the second resistor R2, and the second field effect transistor Q2 is conducted. The second diode D2 is used to reduce the standby power consumption of the system, and the D2 diode can be short-circuited without such requirement. The utility model discloses a discrete component high frequency switch gate drive circuit uses when step-down circuit topological structure as shown in fig. 2, and output voltage feeds back to digital processing chip MCU after third R3, ninth resistance R9 sample, and digital processing chip MCU is according to output voltage state adjustment PWM duty cycle, based on the stable output of prior art control, no longer gives details here. The utility model discloses this kind of discrete component high frequency switch gate drive circuit realizes the drive of high frequency switch gate under few components and very low cost condition, and replacement gate drive IC has improved product nature price ratio, and the product has good market prospect.

The above description is only for the preferred embodiment of the present invention, and the above specific embodiments are not intended to limit the present invention. Within the scope of the technical idea of the present invention, various modifications and alterations can be made, and any person skilled in the art can make modifications, amendments or equivalent replacements according to the above description, all belonging to the protection scope of the present invention.