CN103051183A - Drive circuit of synchronous rectification DC/DC (Direct Current/Direct Current) convertor - Google Patents

Abstract

The invention relates to a drive circuit of a synchronous rectification DC/DC (Direct Current/Direct Current) convertor. The drive circuit and a switch level commonly form the synchronous rectification DC/DC convertor, wherein the switch level comprises a main switch tube, a synchronous rectifier tube, a PWM (Pulse-Width Modulation) controller, an inductance L, a capacitance C and a resistance R; the drive circuit comprises a main switch tube drive module and a synchronous rectifier tube drive module; an output signal PG of the main switch tube drive module is connected with a grid electrode of the main switch tube, and is connected to one input end of the synchronous rectifier tube drive module; one input end of the main switch tube drive module is connected with a PD signal output end of the PWM controller; an output signal NG of the synchronous rectifier tube drive module is connected with a grid electrode of the synchronous rectifier tube and is connected to the other input end of the main switch tube drive module; and the other input end of the synchronous rectifier tube drive module is connected with an ND signal output end of the PWM controller.

Description

The drive circuit of a kind of synchronous rectification DC/DC converter

Technical field

The present invention relates to the drive circuit of a kind of synchronous rectification DC/DC converter, belong to electronic technology field.

Background technology

The low-power consumption of power management class chip, high efficiency more and more become an important indicator of design of circuit system, for low voltage circuit, synchronous rectification can improve power supply conversion efficiency, and the key problem of synchronous rectification is the driving problems of synchronous rectifier.The type of drive of synchronous rectifier is divided into two classes: the synchronous rectification of external drive formula and self-driving type synchronous rectification.Wherein, self-driving type synchronous rectification is divided into again voltage driven type synchronous rectification and current drive-type synchronous rectification.

The gate drive voltage of external drive formula synchronous rectifier need to obtain from additional peripheral hardware drive circuit, for realizing synchronously, drive circuit must be controlled by the driving signal of converter main switch, so the synchronous rectification of external drive formula can provide more accurate control sequential, but its drive circuit is complicated, expensive, therefore less employing external drive formula synchronous rectification.

Voltage driven type synchronous rectification drive voltage signal is from the PWM controller, and synchronous rectifier is automatically opened or turn-offed according to the polarity of voltage of control signal, and simple in structure, economical and efficient becomes the synchronous rectification Driving technique that is subject at present extensive concern.There is the problem that drives the dead band usually in the driving synchronous rectification of conventional voltage, if Dead Time is long, can cause the body diode conducting of rectifying tube, loss is very large, if Dead Time is too short, switching node place parasitic capacitance is not discharged, the rectifying tube conducting, then can discharge by rectifying tube, also will cause than lossy.In recent years, voltage driven type synchronous rectification has obtained very large development, speed synchronous rectification and grid charge transfer voltage of grid charge holding voltage occurred and has driven synchronous rectification, has solved preferably the dead-time problem that synchronous rectification drives.

Current drive-type synchronous rectification is flow through the electric current of synchronous rectifier by detection, determines whether to open or turn-off synchronous rectifier.When synchronous rectifier conducting and electric current flowed to drain electrode from the source electrode of synchronous rectifier, the electric current of detection power MOSFET obtained the driving signal of current drive-type synchronous rectifier.When current reduction is 0 or oppositely the time, synchronous rectifier turn-offs.The current drive-type synchronous rectifier can turn on and off automatically as a general-purpose diode.With respect to the voltage driven type synchronous rectifier, the topological structure of current drive-type synchronous rectifier is independent.That is to say, in existing switch power supply topological structure, can replace rectifier diode with the current drive-type synchronous rectifier.Therefore, the current drive-type synchronous rectifier has versatility, but must impressed current detection means and auxiliary circuit.

Summary of the invention

The present invention overcomes the defective that prior art exists, on the basis of existing research, the drive circuit of a kind of synchronous rectification DC/DC converter has been proposed, by the method control main switch of the staggered time-delay of gate drive signal and conducting and the shutoff of synchronous rectifier, solved the dead-time problem that synchronous rectification drives.

For achieving the above object, the present invention is by the following technical solutions: the drive circuit of a kind of synchronous rectification DC/DC converter, this drive circuit with comprise main switch, synchronous rectifier, the PWM controller, inductance L, the switching stage that capacitor C and resistance R form consists of synchronous rectification DC/DC converter jointly, it is characterized in that: drive circuit comprises main switch driver module and synchronous rectifier driver module, the output signal PG of main switch driver module is connected with the grid of main switch and is connected to input of synchronous rectifier driver module, the main switch that an input of main switch driver module connects the output of PWM controller drives signal PD, the output signal NG of synchronous rectifier driver module is connected and is connected to another input of main switch driver module with the grid of synchronous rectifier, the synchronous rectifier that another input of synchronous rectifier driver module connects the output of PWM controller drives signal ND;

The main switch driver module comprises four couples of metal-oxide-semiconductor MP1 and MN1, metal-oxide-semiconductor MP2 and MN2, metal-oxide-semiconductor MP3 and MN3, metal-oxide-semiconductor MP4 and MN4 totally 8 metal-oxide-semiconductors, 3 two input NOR gate nor_1, nor_2, nor_3, two two input nand gate nand_1, nand_2 and two inverter inv_1, inv_2; Metal-oxide-semiconductor MP1, MP2, MP3, the source electrode of MP4 is connected to power supply Vin, metal-oxide-semiconductor MN1, MN2, MN3, the source electrode of MN4 is connected to ground, the drain electrode of metal-oxide-semiconductor MP1 and MN1 is the output signal port PG of main switch driver module, the grid of metal-oxide-semiconductor MP1, the drain electrode of MP2 and the drain electrode of MN2 are connected to the input of inverter inv_1, the grid of metal-oxide-semiconductor MN1, the drain electrode of MP4 and the drain electrode of MN4 are connected to the input of two input NOR gate nor_3, the drain electrode of metal-oxide-semiconductor MP3 and the drain electrode of MN3 are connected to the grid of metal-oxide-semiconductor MP2, input of two input NOR gate nor_1 and the output of nor_3 are connected to the grid of metal-oxide-semiconductor MN2, the grid of metal-oxide-semiconductor MP3, the input of the grid of MN3 and two input nand gate nand_1 is connected to the output of two input NOR gate nor_1, another input of two input NOR gate nor_1 and the input of nand_2 are an input of main switch driver module, the main switch that connects the output of PWM controller drives signal PD, another input of the output of two input nand gate nand_1 and nand_2 is connected to the grid of metal-oxide-semiconductor MP4, the grid of metal-oxide-semiconductor MN4 is connected to the output of inverter inv_2, the output of the input of inverter inv_2 and two input nand gate nand_2 is connected to another input of two input NOR gate nor_3, another input of two input nand gate nand_1 is connected to the output of two input NOR gate nor_2, and the input of two input NOR gate nor_2 is connected to the output of inverter inv_1;

The synchronous rectifier driver module comprises metal-oxide-semiconductor MP5 and MN5, metal-oxide-semiconductor MP6 and MN6, metal-oxide-semiconductor MP7 and MN7, four couples of metal-oxide-semiconductor MP8 and MN8 be totally 8 metal-oxide-semiconductors, two two input NOR gate nor_4, nor_5,3 two input nand gate nand_3, nand_4, nand_5 and two inverter inv_3, inv_4, wherein, metal-oxide-semiconductor MP5, MP6, MP7, the source electrode of MP8 is connected to power supply Vin, metal-oxide-semiconductor MN5, MN6, MN7, the source electrode of MN8 is connected to ground, the drain electrode of metal-oxide-semiconductor MP5 and MN5 is the output signal port NG of synchronous rectifier driver module, another input port with the main switch driver module, namely another input of two input NOR gate nor_2 connects, the grid of metal-oxide-semiconductor MP5, the drain electrode of MP6 and the drain electrode of MN6 are connected to the input of two input nand gate nand_4, the grid of metal-oxide-semiconductor MN5, the drain electrode of MP8 and the drain electrode of MN8 are connected to the input of inverter inv_3, the drain electrode of metal-oxide-semiconductor MP7 and the drain electrode of MN7 are connected to the grid of MP6, input of two input NOR gate nor_4 and the output of nor_5 are connected to the grid of metal-oxide-semiconductor MN6, the grid of metal-oxide-semiconductor MP7, another input of the grid of MN7 and nand_4 is connected to the output of nor_4, another input of two input NOR gate nor_4 and the input of two input nand gate nand_5 are an input of synchronous rectifier driver module, the synchronous rectifier that connects the output of PWM controller drives signal ND, another input of the output of nand_4 and nand_5 is connected to the grid of metal-oxide-semiconductor MP8, the grid of metal-oxide-semiconductor MN8 is connected to the output of inverter inv_4, the input of inv_4 and the output of nand_5 are connected to the input of nor_5, another input of nor_5 is connected to the output of nand_3, another input that the input of nand_3 is the synchronous rectifier driver module, connect the output signal port PG of main switch driver module, another input of nand_3 is connected to the output of inverter inv_3.

Advantage of the present invention and remarkable result:

(1) the present invention produces conducting and the shutoff that staggered gate drive signal of delaying time is controlled main switch and synchronous rectifier by main switch driver module and synchronous rectifier driver module, there is the dead band in the gate drive signal that produces, the length in dead band can be by changing main switch driver module and synchronous rectifier driver module inside the time-delay of gate circuit regulate, solve the dead-time problem that synchronous rectification drives, thereby improved power supply conversion efficiency.

(2) also consider the dead-time problem of driving tube in the design of main switch driver module of the present invention and synchronous rectifier driver module, added the Dead Time of driving tube, reduced the driving loss of drive circuit.

Description of drawings

Fig. 1 is the overall pattern of drive circuit of the present invention;

Fig. 2 is the electrical schematic diagram of main switch MP0 driver module among the present invention;

Fig. 3 is the electrical schematic diagram of synchronous rectifier MN0 driver module among the present invention;

Fig. 4 is drive circuit of the present invention and the prior art common synchronous rectification DC that consists of of switching stage that comprises main switch MP0, synchronous rectifier MN0, PWM controller etc. and form/DC converter;

Fig. 5 is the simulation waveform figure of PD among the present invention, ND, PG and NG port.

Embodiment

Such as Fig. 1, drive circuit of the present invention comprises main switch driver module and synchronous rectifier driver module, and this drive circuit and the switching stage that comprises that main switch, synchronous rectifier, PWM controller, inductance L, capacitor C and resistance R form shown in Figure 4 consist of synchronous rectification DC/DC converter jointly.The output signal PG of main switch driver module is connected with the grid of main switch MP0 and is connected to input of synchronous rectifier driver module, an input of main switch driver module connects the PD signal output part of PWM controller, the output signal NG of synchronous rectifier driver module and the grid of synchronous rectifier MN0 are connected and are connected to another input of main switch driver module, and another input of synchronous rectifier driver module connects the ND signal output part of PWM controller.

Such as Fig. 2, the main switch driver module comprises four couples of metal-oxide-semiconductor MP1 and MN1, metal-oxide-semiconductor MP2 and MN2, metal-oxide-semiconductor MP3 and MN3, metal-oxide-semiconductor MP4 and MN4 totally 8 metal-oxide-semiconductors, 3 two input NOR gate nor_1, nor_2, nor_3, two two input nand gate nand_1, nand_2 and two inverter inv_1, inv_2; Metal-oxide-semiconductor MP1, MP2, MP3, the source electrode of MP4 is connected to power supply Vin, metal-oxide-semiconductor MN1, MN2, MN3, the source electrode of MN4 is connected to ground, the drain electrode of metal-oxide-semiconductor MP1 and MN1 is the output signal port PG of main switch driver module, the grid of metal-oxide-semiconductor MP1, the drain electrode of MP2 and the drain electrode of MN2 are connected to the input of inverter inv_1, the grid of metal-oxide-semiconductor MN1, the drain electrode of MP4 and the drain electrode of MN4 are connected to the input of two input NOR gate nor_3, the drain electrode of metal-oxide-semiconductor MP3 and the drain electrode of MN3 are connected to the grid of metal-oxide-semiconductor MP2, input of two input NOR gate nor_1 and the output of nor_3 are connected to the grid of metal-oxide-semiconductor MN2, the grid of metal-oxide-semiconductor MP3, the input of the grid of MN3 and two input nand gate nand_1 is connected to the output of two input NOR gate nor_1, another input of two input NOR gate nor_1 and the input of nand_2 are an input of main switch driver module, the PD signal output part that connects the PWM controller, another input of the output of two input nand gate nand_1 and nand_2 is connected to the grid of metal-oxide-semiconductor MP4, the grid of metal-oxide-semiconductor MN4 is connected to the output of inverter inv_2, the output of the input of inverter inv_2 and two input nand gate nand_2 is connected to another input of two input NOR gate nor_3, another input of two input nand gate nand_1 is connected to the output of two input NOR gate nor_2, and the input of two input NOR gate nor_2 is connected to the output of inverter inv_1.

Such as Fig. 3, the synchronous rectifier driver module comprises metal-oxide-semiconductor MP5 and MN5, metal-oxide-semiconductor MP6 and MN6, metal-oxide-semiconductor MP7 and MN7, four couples of metal-oxide-semiconductor MP8 and MN8 be totally 8 metal-oxide-semiconductors, two two input NOR gate nor_4, nor_5,3 two input nand gate nand_3, nand_4, nand_5 and two inverter inv_3, inv_4, wherein, metal-oxide-semiconductor MP5, MP6, MP7, the source electrode of MP8 is connected to power supply Vin, metal-oxide-semiconductor MN5, MN6, MN7, the source electrode of MN8 is connected to ground, the drain electrode of metal-oxide-semiconductor MP5 and MN5 is the output signal port NG of synchronous rectifier driver module, another input port with the main switch driver module, namely another input of two input NOR gate nor_2 connects, the grid of metal-oxide-semiconductor MP5, the drain electrode of MP6 and the drain electrode of MN6 are connected to the input of two input nand gate nand_4, the grid of metal-oxide-semiconductor MN5, the drain electrode of MP8 and the drain electrode of MN8 are connected to the input of inverter inv_3, the drain electrode of metal-oxide-semiconductor MP7 and the drain electrode of MN7 are connected to the grid of MP6, input of two input NOR gate nor_4 and the output of nor_5 are connected to the grid of metal-oxide-semiconductor MN6, the grid of metal-oxide-semiconductor MP7, another input of the grid of MN7 and nand_4 is connected to the output of nor_4, another input of two input NOR gate nor_4 and the input of two input nand gate nand_5 are an input of synchronous rectifier driver module, the ND signal output part that connects the PWM controller, another input of the output of nand_4 and nand_5 is connected to the grid of metal-oxide-semiconductor MP8, the grid of metal-oxide-semiconductor MN8 is connected to the output of inverter inv_4, the input of inv_4 and the output of nand_5 are connected to the input of nor_5, another input of nor_5 is connected to the output of nand_3, another input that the input of nand_3 is the synchronous rectifier driver module, connect the output signal port PG of main switch driver module, another input of nand_3 is connected to the output of inverter inv_3.

Such as Fig. 4, the drive circuit and the prior art that the present invention includes main switch driver module and synchronous rectifier driver module formation comprise that the switching stage that main switch MP0, synchronous rectifier MN0, PWM controller, inductance L, capacitor C and resistance R consist of has consisted of synchronous rectification DC/DC converter jointly.The source electrode of main switch MP0 is connected to power supply Vin, one end of the source electrode of synchronous rectifier MN0, capacitor C and an end of resistance R all are connected to ground, the drain electrode of the drain electrode of main switch MP0 and synchronous rectifier MN0 is connected to an end of inductance L, the other end of the other end of inductance L, the other end of capacitor C, resistance R is connected with the input of PWM controller, and this port also is the output end vo ut of DC/DC converter.The grid of main switch MP0 is connected to the output port PG of main switch driver module, the grid of synchronous rectifier MN0 is connected to the output port NG of synchronous rectifier driver module, the output PD of PWM controller is connected to an input port of main switch driver module, and another input port of main switch driver module connects NG.The output of PWM controller connects the input port that ND connects the synchronous rectifier driver module, and another input port of synchronous rectifier driver module connects PG.

Suppose that two output waveforms (PD and ND) that the PWM controller produces are identical, do not have time-delay, the operation principle of drive circuit is as follows: the MP5 in the MP1 in the main switch driver module and MN1, MP2 and MN2, MP3 and MN3, MP4 and four pairs of metal-oxide-semiconductors of MN4 and the synchronous rectifier driver module and MN5, MP6 and MN6, MP7 and MN7, MP8 and four pairs of metal-oxide-semiconductors of MN8 play the inverter effect respectively.

When PD and ND are low level, in the synchronous rectifier driver module, nand_5 is output as high level, nor_5 is output as low level, so nor_4 is output as high level, MP7 and MN7 are output as low level, MP6 and MN6 are output as high level, so nand_4 is output as low level, MP8 and MN8 are output as high level, so MP5 and MN5 output NG are low level; In the main switch driver module, nand_2 is output as high level, and nor_3 is output as low level, so nor_1 is output as high level, MP3 and MN3 are output as low level, MP2 and MN2 are output as high level, and inv_1 is output as low level, because NG is low level, then nor_2 is output as high level, so nand_1 is output as low level, MP4 and MN4 are output as high level, so MP1 and MN1 output PG are low level.

In like manner, when PD and ND were high level, in the main switch driver module, nor_1 was output as low level, MP3 and MN3 are output as high level, nand_1 is output as high level, and then nand_2 is output as low level, and inv_2 is output as high level, so MP4 and MN4 are output as low level, then nor_3 is output as high level, and MP2 and MN2 are output as low level, so MP1 and MN1 output PG are high level.In the synchronous rectifier driver module, nor_4 is output as low level, and MP7 and MN7 are output as high level, nand_4 is output as high level, then nand_5 is output as low level, and inv_4 is output as high level, so MP8 and MN8 are output as low level, inv_3 is output as high level, because PG is high level, then nand_3 is output as low level, and nor_5 is output as high level, MP6 and MN6 are output as low level, so MP5 and MN5 output NG are high level.

In sum, when PD and ND were low level, the saltus step of the output NG of synchronous rectifier driver module elder generation was low level, and then the output PG saltus step of main switch driver module is low level; When PD and ND were high level, the saltus step of the output PG of main switch driver module elder generation was high level, and then the output NG saltus step of synchronous rectifier driver module is high level.

The simulation waveform figure of PD, ND, PG and NG port as shown in Figure 5.Dead Time between PG and the NG is to be produced by the time-delay of the gate circuit of main switch driver module and synchronous rectifier driver module inside, and this delay time can be adjusted to optimum Dead Time.There is Dead Time in simultaneously in the course of the work simultaneously conducting of MP1 and MN1, MP2 and MN2, MP4 and MN4, MP5 and MN5, MP6 and MN6 and MP8 and MN8, has reduced the driving loss of drive circuit.

Claims (1)

1. the drive circuit of synchronous rectification DC/DC converter, this drive circuit with comprise main switch, synchronous rectifier, the PWM controller, inductance L, the switching stage that capacitor C and resistance R form consists of synchronous rectification DC/DC converter jointly, it is characterized in that: drive circuit comprises main switch driver module and synchronous rectifier driver module, the output signal PG of main switch driver module is connected with the grid of main switch and is connected to input of synchronous rectifier driver module, the main switch that an input of main switch driver module connects the output of PWM controller drives signal PD, the output signal NG of synchronous rectifier driver module is connected and is connected to another input of main switch driver module with the grid of synchronous rectifier, the synchronous rectifier that another input of synchronous rectifier driver module connects the output of PWM controller drives signal ND;

The main switch driver module comprises four couples of metal-oxide-semiconductor MP1 and MN1, metal-oxide-semiconductor MP2 and MN2, metal-oxide-semiconductor MP3 and MN3, metal-oxide-semiconductor MP4 and MN4 totally 8 metal-oxide-semiconductors, 3 two input NOR gate nor_1, nor_2, nor_3, two two input nand gate nand_1, nand_2 and two inverter inv_1, inv_2; Metal-oxide-semiconductor MP1, MP2, MP3, the source electrode of MP4 is connected to power supply Vin, metal-oxide-semiconductor MN1, MN2, MN3, the source electrode of MN4 is connected to ground, the drain electrode of metal-oxide-semiconductor MP1 and MN1 is the output signal port PG of main switch driver module, the grid of metal-oxide-semiconductor MP1, the drain electrode of MP2 and the drain electrode of MN2 are connected to the input of inverter inv_1, the grid of metal-oxide-semiconductor MN1, the drain electrode of MP4 and the drain electrode of MN4 are connected to the input of two input NOR gate nor_3, the drain electrode of metal-oxide-semiconductor MP3 and the drain electrode of MN3 are connected to the grid of metal-oxide-semiconductor MP2, input of two input NOR gate nor_1 and the output of nor_3 are connected to the grid of metal-oxide-semiconductor MN2, the grid of metal-oxide-semiconductor MP3, the input of the grid of MN3 and two input nand gate nand_1 is connected to the output of two input NOR gate nor_1, another input of two input NOR gate nor_1 and the input of nand_2 are an input of main switch driver module, the main switch that connects the output of PWM controller drives signal PD, another input of the output of two input nand gate nand_1 and nand_2 is connected to the grid of metal-oxide-semiconductor MP4, the grid of metal-oxide-semiconductor MN4 is connected to the output of inverter inv_2, the output of the input of inverter inv_2 and two input nand gate nand_2 is connected to another input of two input NOR gate nor_3, another input of two input nand gate nand_1 is connected to the output of two input NOR gate nor_2, and the input of two input NOR gate nor_2 is connected to the output of inverter inv_1;

The synchronous rectifier driver module comprises metal-oxide-semiconductor MP5 and MN5, metal-oxide-semiconductor MP6 and MN6, metal-oxide-semiconductor MP7 and MN7, four couples of metal-oxide-semiconductor MP8 and MN8 be totally 8 metal-oxide-semiconductors, two two input NOR gate nor_4, nor_5,3 two input nand gate nand_3, nand_4, nand_5 and two inverter inv_3, inv_4, wherein, metal-oxide-semiconductor MP5, MP6, MP7, the source electrode of MP8 is connected to power supply Vin, metal-oxide-semiconductor MN5, MN6, MN7, the source electrode of MN8 is connected to ground, the drain electrode of metal-oxide-semiconductor MP5 and MN5 is the output signal port NG of synchronous rectifier driver module, another input port with the main switch driver module, namely another input of two input NOR gate nor_2 connects, the grid of metal-oxide-semiconductor MP5, the drain electrode of MP6 and the drain electrode of MN6 are connected to the input of two input nand gate nand_4, the grid of metal-oxide-semiconductor MN5, the drain electrode of MP8 and the drain electrode of MN8 are connected to the input of inverter inv_3, the drain electrode of metal-oxide-semiconductor MP7 and the drain electrode of MN7 are connected to the grid of MP6, input of two input NOR gate nor_4 and the output of nor_5 are connected to the grid of metal-oxide-semiconductor MN6, the grid of metal-oxide-semiconductor MP7, another input of the grid of MN7 and nand_4 is connected to the output of nor_4, another input of two input NOR gate nor_4 and the input of two input nand gate nand_5 are an input of synchronous rectifier driver module, the synchronous rectifier that connects the output of PWM controller drives signal ND, another input of the output of nand_4 and nand_5 is connected to the grid of metal-oxide-semiconductor MP8, the grid of metal-oxide-semiconductor MN8 is connected to the output of inverter inv_4, the input of inv_4 and the output of nand_5 are connected to the input of nor_5, another input of nor_5 is connected to the output of nand_3, another input that the input of nand_3 is the synchronous rectifier driver module, connect the output signal port PG of main switch driver module, another input of nand_3 is connected to the output of inverter inv_3.

Images