CN218482787U

CN218482787U - Source synchronous driving circuit

Info

Publication number: CN218482787U
Application number: CN202222563941.9U
Authority: CN
Inventors: 陈育辉; 王志文; 申志鹏; 夏伟昇
Original assignee: Mornsun Guangzhou Science and Technology Ltd
Current assignee: Mornsun Guangzhou Science and Technology Ltd
Priority date: 2022-09-27
Filing date: 2022-09-27
Publication date: 2023-02-14
Anticipated expiration: 2032-09-27

Abstract

The utility model relates to a switching power supply field discloses a source synchronous drive circuit, is applied to the flyback converter who adopts source drive, and it increases source synchronous drive circuit on current source drive circuit's basis, and source synchronous drive circuit includes: high low side drive IC, diode D5 and electric capacity C4, through drawing low high avris with high low side drive IC reference ground, supply voltage charges electric capacity C4 through diode D5, when PWMIC gives control signal, give high low side drive IC with the signal in step, for source electrode drive top tube synchronous output drive signal, realize the quick switch to source electrode drive top tube, avoid the top tube turn-off too slowly to lead to stabilivolt D1 to absorb too big main power electric current and damage. The utility model discloses can realize source drive circuit synchronous drive, promote switching power supply's efficiency.

Description

Source synchronous driving circuit

Technical Field

The utility model relates to a switching power supply design field, in particular to source synchronous drive circuit.

Background

In recent years, with the rapid development of the photovoltaic energy storage industry, the high-voltage transmission industry and other industries, the input voltage of a power distribution system of the photovoltaic energy storage industry is up to thousands of volts, and the existing traditional converter is difficult to have a proper high-voltage tube to meet the design requirement, so that some topologies for connecting a plurality of MOS tubes in series to widen the input voltage appear on the market, but the topologies need to ensure the consistency of the opening of the plurality of MOS tubes, so that a driving transformer needs to be added to carry out synchronous driving, and the addition of the driving transformer undoubtedly increases the cost and the volume of the system, and is not favorable for the development direction of small volume and high power density of the system. The main principle of source electrode driving is to fix the grid voltage of the MOS tube at a certain value, and the source electrode voltage is changed to control the on-off state of the MOS tube, so that the input voltage is widened, and a driving transformer is not needed, thereby greatly reducing the volume of a power supply system.

The existing source electrode driving circuit is referred to as a figure 1, and mainly comprises a switch tube Q1, a switch tube Q2, a resistor R1, a clamping capacitor C1, a voltage-stabilizing tube D2, a transformer T1, an output circuit and an auxiliary power supply circuit, wherein a certain time delay exists between the conduction and the disconnection of the switch tube Q1 and the switch tube Q2, when the switch tube Q2 is disconnected and the switch tube Q1 is disconnected too slowly, a main power current flows through the switch tube Q1 and the voltage-stabilizing tube D2 and flows into the voltage-stabilizing tube D1, so that the voltage of a drain source electrode and a source electrode when the power switch tube is conducted is not zero, voltages flowing through two ends of the switch tube Q1 and the switch tube Q2 and currents flowing through the switch tube D1 have obvious overlapping regions, switching loss generated in the overlapping regions can cause the problems of low system efficiency and heating of the voltage-stabilizing tube D1, and the temperature rise of the voltage-stabilizing tube D1 along with the increase of switching frequency, so that the high-frequency development of a switching power supply is limited, the high-frequency development of a system is difficult to be reduced, and the synchronous switching performance of the source electrode driving tube Q1 and the switch tube Q2 can be greatly reduced if the source electrode driving circuit is disconnected.

SUMMERY OF THE UTILITY MODEL

In view of this, the to-be-solved technical problem of the utility model is to provide a source synchronous drive circuit, mainly be applied to switching power supply under the wide voltage input, effectively reduce the loss of stabilivolt, promote switching power supply's efficiency.

The utility model aims at realizing through the following technical scheme:

a source electrode synchronous driving circuit is applied to a flyback converter driven by a source electrode, the flyback converter comprises an input circuit, an output circuit and a transformer T1, the input circuit is connected with the output circuit through the transformer T1, and the input circuit comprises a resistor R1, a capacitor C1, a switch tube Q2, a voltage-stabilizing tube D1 and a voltage-stabilizing tube D2; the primary side input end is sequentially connected with a first end of a primary side winding P1 of a transformer T1, a second end of the primary side winding P1 of the transformer T1, a drain electrode of a switch tube Q1, a source electrode of the switch tube Q1, a drain electrode of the switch tube Q2, a source electrode of the switch tube Q2 and a primary side input ground in series, the primary side input end is also sequentially connected with a first end of a resistor R1, a second end of the resistor R1, a cathode of a voltage regulator tube D1, an anode of the voltage regulator tube D1 and the primary side input ground in series, a capacitor C1 is connected with two ends of the voltage regulator tube D1 in parallel, the anode of the voltage regulator tube D2 is connected with the source electrode of the switch tube Q1, the cathode of the voltage regulator tube D2 is connected with a grid electrode of the switch tube Q1, and a grid electrode of the switch tube Q2 is connected with a driving pin of a PWM IC;

the source synchronous driving circuit includes: the high-low side driving circuit comprises a high-low side driving IC, a diode D5 and a capacitor C4, wherein the anode of the diode D5 is connected with the power supply end of the auxiliary power supply circuit, the cathode of the diode D5 is connected with the first end of the capacitor C4, the second end of the capacitor C4 is connected with the drain electrode of the switch tube Q2, the signal input pin of the high-low side driving IC is connected with the driving pin of the PWM IC, the high-side power supply pin of the high-low side driving IC is connected with the first end of the capacitor C4, the high-side reference pin of the high-low side driving IC is connected with the second end of the capacitor C4, and the high-side output pin of the high-low side driving IC is connected with the grid electrode of the switch tube Q1.

Preferably, the auxiliary power supply circuit includes a secondary winding S2 of the transformer T1, a diode D4 and a capacitor C3, a first end of the secondary winding S2 of the transformer T1 is connected to an anode of the diode D4, a cathode of the diode D4 is connected to a first end of the capacitor C3 and a power supply terminal VCC of the auxiliary power supply circuit, and a second end of the secondary winding S2 of the transformer is connected to a second end of the capacitor C3 and a primary input ground.

Preferably, the auxiliary power supply circuit comprises an auxiliary winding S3 of the transformer T1, a diode D6 and a capacitor C5, a first end of the auxiliary winding S3 of the transformer T1 is connected to an anode of the diode D6, a cathode of the diode D6 is connected to a first end of the capacitor C5 and a power supply terminal VCC _ H of the auxiliary power supply circuit, and a second end of the secondary winding S3 of the transformer is connected to a second end of the capacitor C5 and a high-side reference ground pin of the high-low side driver IC.

The utility model discloses a theory of operation can combine specific embodiment to carry out the detailed description at the back, and the here is not repeated, compares with prior art, the utility model discloses following beneficial effect has:

1. the utility model discloses an increase synchronous drive circuit, can improve switch tube Q1's turn-off speed, avoid turning off at switch tube Q2, switch tube Q1 turn-off when slow, the main power electric current flows through the clamper stabilivolt D1, reduce stabilivolt D1's loss and reduce stabilivolt D1's temperature rise, solve in the high-voltage input switching power supply product harsh to the switch tube lectotype, stabilivolt D1 loss is big, the system efficiency is low, the problem of unable high frequency, promote switching power supply system's performance.

2. The utility model discloses circuit structure is simple, and the device lectotype is simple.

Drawings

FIG. 1 is a schematic diagram of a conventional source driver circuit;

fig. 2 is a schematic diagram of a first embodiment of the source synchronous driving circuit of the present invention;

fig. 3 is a waveform diagram of the first embodiment of the source synchronous driving circuit of the present invention;

fig. 4 is a schematic diagram of a second embodiment of the source synchronous driving circuit of the present invention.

Detailed Description

First embodiment

Fig. 2 is a schematic diagram of the first embodiment of the source synchronous driving circuit of the present invention, which is applied to a flyback converter driven by a source, the flyback converter includes an input circuit, a transformer T1, an output circuit and an auxiliary power supply circuit, the input circuit is connected to the output circuit and the auxiliary power supply circuit through the transformer T1, wherein the transformer T1 is composed of a primary winding P1, a secondary winding S1 and an auxiliary winding S2; the input circuit comprises a resistor R1, a capacitor C1, a switch tube Q2, a voltage-regulator tube D1 and a voltage-regulator tube D2, wherein a primary-side input terminal Vin is sequentially connected in series with a first end of a primary-side winding P1 of a transformer T1, a second end of the primary-side winding P1 of the transformer T1, a drain electrode of the switch tube Q1, a source electrode of the switch tube Q1, a drain electrode of the switch tube Q2, a source electrode of the switch tube Q2 and a primary-side input ground GND, the primary-side input terminal Vin is also sequentially connected in series with a first end of the resistor R1, a second end of the resistor R1, a cathode of the voltage-regulator tube D1, an anode of the voltage-regulator tube D1 and the primary-side input ground GND, the capacitor C1 is connected in parallel with two ends of the voltage-regulator tube D1, an anode of the voltage-regulator tube D2 is connected with the source electrode of the switch tube Q1, a cathode of the voltage-regulator tube D2 is connected with a gate of the switch tube Q1, and a gate of the switch tube Q2 is connected with a driving pin of a PWM IC; the output circuit comprises a capacitor C2, a diode D3 and a diode D4, the first end of the output winding S1 is connected with the anode of the diode D3, the cathode of the diode D3 is connected with the first end of the capacitor C2 and the secondary output end VOUT +, and the second end of the secondary winding S2 is connected with the second end of the diode C2 and the secondary output end VOUT-; the auxiliary power supply circuit comprises a diode D4 and a capacitor C3, the first end of the auxiliary winding S2 is connected with the anode of the diode D4, the cathode of the diode D4 is connected with the first end of the capacitor C3 and the power supply end VCC of the auxiliary power supply circuit, and the second end of the auxiliary winding S2 is connected with the second end of the capacitor C3 and the primary side input ground GND.

The source synchronous driving circuit includes: the high-low side driving circuit comprises a high-low side driving IC, a diode D5 and a capacitor C4, wherein the anode of the diode D5 is connected with a power supply terminal VCC of the auxiliary power supply circuit, the cathode of the diode D5 is connected with the first terminal of the capacitor C4, the second terminal of the capacitor C4 is connected with the drain of a switch tube Q2, a signal input pin HI of the high-low side driving IC is connected with a driving pin of the PWM IC, a high side power supply pin VB of the high-low side driving IC is connected with the first terminal of the capacitor C4, a high side reference pin VS of the high-low side driving IC is connected with the second terminal of the capacitor C4, and a high side output pin HO of the high-low side driving IC is connected with the grid of the switch tube Q1.

Fig. 3 is a waveform diagram of the first embodiment of the source synchronous driving circuit of the present invention, and the working principle of the source synchronous driving circuit of this embodiment is:

when the control signal given by the PWM IC is switched from low level to high level, the switching tube Q2 is turned on, the source voltage of the switching tube Q1 is pulled down, and the gate potential of the switching tube Q1 is maintained, and since the gate-source voltage Vgs of the switching tube Q1 is increased, when the switching tube Q1 reaches the turn-on threshold voltage Vth, the switching tube Q1 is turned on passively.

When the control signal given by the PWM IC is switched from a high level to a low level, the switching tube Q2 is turned off, the source potential of the switching tube Q1 is gradually raised, the gate potential of the switching tube Q1 is not changed, and the gate-source voltage Vgs of the switching tube Q1 is gradually decreased until the threshold voltage of the switching tube Q1 is lower than the turn-off threshold voltage, and the switching tube Q1 starts to be turned off. The Vds voltage of the switch tube Q2 is clamped through the voltage stabilizing tube D1, and because the switch tube Q2 is turned off slowly for the switch tube Q1, a certain time delay exists, namely time t1, so that the iL current flows through the switch tube Q1 and the voltage stabilizing tube D2 and then flows into the voltage stabilizing tube D1, the voltage stabilizing tube D1 absorbs overlarge current, and the voltage Vz1 on the voltage stabilizing tube D1 is overlapped with the flowing current Iz1 to form great loss and generate heat seriously.

By adding the source electrode synchronous driving circuit, when a control signal given by the PWM IC is switched from a low level to a high level, the signal is synchronously sent to the high-side and low-side driving IC, the switching tube Q2 starts to be conducted, the source electrode voltage of the switching tube Q1 is pulled down, the bootstrap capacitor C4 is charged by VCC voltage through the diode D5, the HO pin of the high-side output pin of the high-side and low-side driving IC outputs the high level at the moment, the voltage of the bootstrap capacitor C4 is extracted to drive the switching tube Q1, the switching tube Q1 is quickly turned on, and the switching loss of the switching tube Q1 is reduced.

When a control signal given by the PWM IC is switched from a high level to a low level, a signal is synchronously sent to the high-low side driving IC, the switching tube Q2 starts to be cut off, at the moment, the HO pin of the high-side output pin of the high-low side driving IC outputs the low level, the switching tube Q1 is quickened to be cut off by utilizing the low delay characteristic of the high-low side driving IC, the current flowing into the voltage regulator tube D1 is further reduced, the time of t1 is reduced, and the loss of the voltage regulator tube D1 is further reduced. After the power supply circuit is turned off, the voltage of a Vs point is raised, and the diode D5 plays a role in preventing backflow to protect the power supply end VCC of the auxiliary power supply circuit.

The utility model discloses a draw low with high low side driver IC's high avris reference, supply voltage charges to electric capacity C4 through diode D5, when PWM IC gives control signal, give high low side driver IC with the signal in step, for source drive top tube (switch tube Q1) synchronous output drive signal, realize the fast switch to source drive top tube (switch tube Q1), avoid top tube (switch tube Q1) turn-off to lead to stabilivolt D1 to absorb too big main power electric current and damage too slowly. The utility model discloses can realize source drive circuit synchronous drive, promote switching power supply's efficiency.

Second embodiment

Fig. 4 is a schematic diagram of a second embodiment of the source synchronous driving circuit of the present invention, which is different from the first embodiment in that: in this embodiment, the auxiliary power supply circuit includes an auxiliary winding S3 of a transformer T1, a diode D6 and a capacitor C5, a first end of the auxiliary winding S3 of the transformer T1 is connected to an anode of the diode D6, a cathode of the diode D6 is connected to a first end of the capacitor C5 and a power supply terminal VCC _ H of the auxiliary power supply circuit, a second end of the secondary winding S3 of the transformer is connected to a second end of the capacitor C5 and a GND _ H port, the GND _ H port is connected to a high-side reference ground of a high-low side driving IC of the source synchronous driving circuit and a second end of the capacitor C4, an anode of the diode D5 of the source synchronous driving circuit is connected to the power supply terminal VCC _ H of the auxiliary power supply circuit, a cathode of the diode D5 is connected to a first end of the capacitor C4, a second end of the capacitor C4 is connected to a drain of the switching tube Q2 and the GND _ H port, and other relationships are not changed.

The main differences between the working principle of the present embodiment and the first embodiment are as follows: when a control signal given by the PWM IC is switched from a low level to a high level, the switching tube Q2 starts to be conducted, and the auxiliary winding S3 is added, the diode D5 is used for rectification, the capacitor C5 is charged, and the charging speed of the capacitor C4 can be increased. VCC _ H voltage charges bootstrap capacitor C4 through diode D3, and then accelerates to turn off switch tube Q1, and then reduces the electric current that flows into stabilivolt D1, reduces the time of t1, and then reduces stabilivolt D1's loss. The other operation of this embodiment is the same as that of the first embodiment, and will not be described.

The above are only embodiments of the present invention, and it should be noted that the above embodiments should not be considered as limitations of the present invention, and for those skilled in the art, a plurality of modifications and decorations can be made without departing from the spirit and scope of the present invention, and these modifications and decorations should also be considered as protection scope of the present invention.

Claims

1. A source electrode synchronous driving circuit is applied to a flyback converter driven by a source electrode, the flyback converter comprises an input circuit, an output circuit and a transformer T1, the input circuit is connected with the output circuit through the transformer T1, and the input circuit comprises a resistor R1, a capacitor C1, a switch tube Q2, a voltage-stabilizing tube D1 and a voltage-stabilizing tube D2; the primary side input end is sequentially connected with a first end of a primary side winding P1 of a transformer T1, a second end of the primary side winding P1 of the transformer T1, a drain electrode of a switch tube Q1, a source electrode of the switch tube Q1, a drain electrode of a switch tube Q2, a source electrode of the switch tube Q2 and a primary side input ground in series, the primary side input end is also sequentially connected with a first end of a resistor R1, a second end of the resistor R1, a cathode of a voltage regulator tube D1, an anode of the voltage regulator tube D1 and the primary side input ground in series, a capacitor C1 is connected to two ends of the voltage regulator tube D1 in parallel, an anode of the voltage regulator tube D2 is connected with the source electrode of the switch tube Q1, a cathode of the voltage regulator tube D2 is connected with a grid electrode of the switch tube Q1, and a grid electrode of the switch tube Q2 is connected with a drive pin of a PWMIC;

wherein the source synchronous drive circuit comprises: the high-low side driving circuit comprises a high-low side driving IC, a diode D5 and a capacitor C4, wherein the anode of the diode D5 is connected with the power supply end of the auxiliary power supply circuit, the cathode of the diode D5 is connected with the first end of the capacitor C4, the second end of the capacitor C4 is connected with the drain electrode of a switch tube Q2, the signal input pin of the high-low side driving IC is connected with the driving pin of the PWMIC, the high-side power supply pin of the high-low side driving IC is connected with the first end of the capacitor C4, the high-side reference pin of the high-low side driving IC is connected with the second end of the capacitor C4, and the high-side output pin of the high-low side driving IC is connected with the grid electrode of the switch tube Q1.

2. The source synchronous drive circuit according to claim 1, wherein: the auxiliary power supply circuit comprises a secondary winding S2 of the transformer T1, a diode D4 and a capacitor C3, wherein the first end of the secondary winding S2 of the transformer T1 is connected with the anode of the diode D4, the cathode of the diode D4 is connected with the first end of the capacitor C3 and the power supply end VCC of the auxiliary power supply circuit, and the second end of the secondary winding S2 of the transformer is connected with the second end of the capacitor C3 and the primary input ground.

3. The source synchronous drive circuit according to claim 1, wherein: the auxiliary power supply circuit comprises an auxiliary winding S3 of a transformer T1, a diode D6 and a capacitor C5, wherein a first end of the auxiliary winding S3 of the transformer T1 is connected with an anode of the diode D6, a cathode of the diode D6 is connected with a first end of the capacitor C5 and a power supply end VCC _ H of the auxiliary power supply circuit, and a second end of the auxiliary winding S3 of the transformer is connected with a second end of the capacitor C5 and a high-side reference ground pin of the high-side and low-side drive IC.