CN-224233544-U - Driving circuit and switching power supply

CN224233544UCN 224233544 UCN224233544 UCN 224233544UCN-224233544-U

Abstract

The utility model discloses a driving circuit and a switching power supply, wherein the driving circuit comprises a primary winding, an input driving signal source, a first secondary winding, a first output circuit connected with the primary winding, a second secondary winding, a second output circuit connected with the second secondary winding, and a first capacitor, a second capacitor and a second capacitor, wherein the first diode, the first MOS tube, the voltage limiting circuit and the negative pressure module are the same, one end of the negative pressure module is connected with one end of the corresponding secondary winding, the other end of the negative pressure module is connected with a grid electrode of a driven switching tube, the first end of the voltage limiting circuit is connected with the cathode of the first diode and the other end of the corresponding secondary winding, the second end of the voltage limiting circuit is connected with the grid electrode of the first MOS tube, the third end of the voltage limiting circuit, the anode of the first diode and the source electrode of the first MOS tube are connected with the source electrode of the driven switching tube, and the first capacitor and the second capacitor are arranged between the first end and the second end of the voltage limiting circuit. The utility model provides a low-cost and stable SiC driving circuit scheme.

Inventors

YUAN YUAN
Yin Zenghe

Assignees

广州金升阳科技有限公司

Dates

Publication Date: 20260512
Application Date: 20250326

Claims (8)

1. A driving circuit is characterized by comprising a transformer magnetic core, a primary winding, a first secondary winding, a first output circuit, a second secondary winding and a second output circuit, wherein the primary winding is used for inputting a driving signal source; The first output circuit and the second output circuit have the same structure and both comprise: The negative voltage circuit comprises a first diode, a first MOS tube, a voltage limiting circuit and a negative voltage module, wherein one end of the negative voltage module and the drain electrode of the first MOS tube are simultaneously connected with one end of a corresponding secondary winding, the other end of the negative voltage module is used for being connected with the grid electrode of a driven switching tube, the first end of the voltage limiting circuit and the cathode of the first diode are simultaneously connected with the other end of the corresponding secondary winding, the second end of the voltage limiting circuit is connected with the grid electrode of the first MOS tube, the third end of the voltage limiting circuit, the anode of the first diode and the source electrode of the first MOS tube are connected together and are used for being connected with the source electrode of the driven switching tube, a first capacitor is arranged between the first end and the second end of the voltage limiting circuit, and a second capacitor is arranged between the second end and the third end of the voltage limiting circuit; when the input driving signal source is at a high level, the first secondary winding, the corresponding negative pressure module, the corresponding grid capacitor of the driven switching tube and the corresponding first diode form a first driving loop to provide a first driving voltage; When the input driving signal source is switched to a low level, the voltage at two ends of the first secondary winding is zero, the grid capacitance of the corresponding driven switching tube, the corresponding negative pressure module, the first secondary winding and the corresponding voltage limiting circuit form a first loop, the grid capacitance of the corresponding driven switching tube is discharged, meanwhile, the capacitance in the corresponding voltage limiting circuit is charged, the voltage at two ends of the second capacitance in the corresponding voltage limiting circuit is increased, the corresponding first MOS tube is stably conducted through the corresponding voltage limiting circuit, and the corresponding negative pressure module provides negative driving voltage for the corresponding driven switching tube.
2. The driving circuit according to claim 1, wherein the voltage limiting circuit further comprises three diodes, the anode of the first diode and the cathode of the second diode are connected together and then connected to the second end of the voltage limiting circuit, the cathode of the first diode and one end of the first capacitor are connected together and then connected to the first end of the voltage limiting circuit, the anode of the second diode and the cathode of the third diode are simultaneously connected to the other end of the first capacitor, and the anode of the third diode is connected to the third end of the voltage limiting circuit.
3. The driving circuit according to claim 1, wherein the negative pressure module comprises a capacitor and a resistor, one end of the capacitor is connected to one end of the negative pressure module, the other end of the capacitor is connected to one end of the resistor, and the other end of the resistor is connected to the other end of the negative pressure module.
4. The driving circuit according to claim 3, wherein the negative voltage module further comprises a zener diode, a cathode of the zener diode is connected to one end of the negative voltage module, and an anode of the zener diode is connected to the other end of the capacitor.
5. The driving circuit according to claim 3 or 4, wherein the negative voltage module further comprises a diode, a cathode of the diode is connected to one end of the negative voltage module, and an anode of the diode is connected to the other end of the resistor.
6. The driving circuit according to claim 1, wherein the driving circuit further comprises a resistor, one end of the resistor is connected to the other end of the negative pressure module, and the other end of the resistor is connected to a connection point between the anode of the first diode, the other end of the first charge storage unit, and the source electrode of the first MOS tube.
7. The driving circuit according to claim 1 or 6, wherein the driving circuit further comprises two zener diodes, wherein the cathode of one zener diode is connected to the other end of the negative pressure module, the anode of the other zener diode is connected to the anode of the other zener diode, and the cathode of the other zener diode is connected to a connection point of the anode of the first diode, the other end of the first charge storage unit, and the source of the first MOS transistor.
8. A switching power supply employing a half-bridge topology, characterized in that the switching power supply comprises the drive circuit of any one of claims 1 to 7.

Description

Driving circuit and switching power supply Technical Field The utility model belongs to the field of power electronics, and particularly relates to a driving circuit and a switching power supply. Background Along with the development of power electronics technology, the SiC MOS tube has been widely used in a plurality of fields such as automobile charging, photovoltaic power generation, rail transit and data center by virtue of the advantages of high voltage resistance, high switching speed, small reverse recovery and the like. In order to better exert the conduction performance of the SiC MOS, the gate voltage of the SiC MOS is usually controlled to be 15-18V when the SiC MOS is conducted, and meanwhile, in order to avoid the false turn-on of the SiC MOS, the gate voltage of the SiC MOS is usually controlled to be-3 to-5V when the SiC MOS is turned off. The adoption of the isolation drive IC integrating negative pressure has the advantages of higher cost and limited driving capability, and the extra power supply cost is also required to be increased for the half-bridge topology. The transformer isolation driving scheme is a low-cost scheme, the isolation type SiC driving circuit shown in fig. 1 is a scheme proposed in patent document CN 116388534A, wherein a secondary winding of a transformer forms a loop through two resistors R1 and R2, if the resistance value of R1 and R2 is small, a larger load current is caused in the secondary winding of the transformer, driving loss and front-stage burden are increased, if the resistance value of R1 and R2 is too large, the switching speed of a switching tube Q1 is limited, thereby affecting the switching speed of a substituted switching tube U1 and causing larger switching loss, in addition, in order to accelerate the switching process of the switching tube Q1, the switching tube Q1 usually adopts a low-voltage MOS, and a driving power supply born by the switching tube Q1 is usually not too high. In summary, in CN 116388534A, a suitable driving voltage of the switching tube Q1 is obtained by adopting a voltage division manner of connecting resistors R1 and R2 in series, as described above, the small resistance values of the resistors R1 and R2 generate larger load current and loss, and the large resistance values of the resistors R1 and R2 generate larger switching loss, so that it is needed to provide a low-loss, low-cost and stable SiC driving circuit scheme, which can fully exert the excellent performance of SiC and bring higher economic benefit. Disclosure of utility model In view of the above, the present utility model aims to provide a solution to at least some of the technical problems of the prior art. In order to achieve the above purpose, the present utility model adopts the following technical scheme: As a first aspect of the present utility model, an embodiment of a driving circuit is provided as follows: The driving circuit comprises a transformer magnetic core, a primary winding, a first secondary winding, a first output circuit, a second secondary winding and a second output circuit, wherein the primary winding is used for inputting a driving signal source; The first output circuit and the second output circuit have the same structure and both comprise: The negative voltage circuit comprises a first diode, a first MOS tube, a voltage limiting circuit and a negative voltage module, wherein one end of the negative voltage module and the drain electrode of the first MOS tube are simultaneously connected with one end of a corresponding secondary winding, the other end of the negative voltage module is used for being connected with the grid electrode of a driven switching tube, the first end of the voltage limiting circuit and the cathode of the first diode are simultaneously connected with the other end of the corresponding secondary winding, the second end of the voltage limiting circuit is connected with the grid electrode of the first MOS tube, the third end of the voltage limiting circuit, the anode of the first diode and the source electrode of the first MOS tube are connected together and are used for being connected with the source electrode of the driven switching tube, a first capacitor is arranged between the first end and the second end of the voltage limiting circuit, and a second capacitor is arranged between the second end and the third end of the voltage limiting circuit; when the input driving signal source is at a high level, the first secondary winding, the corresponding negative pressure module, the corresponding grid capacitor of the driven switching tube and the corresponding first diode form a first driving loop to provide a first driving voltage; When the input driving signal source is switched to a low level, the voltage at two ends of the first secondary winding is zero, the grid capacitance of the corresponding driven switching tube, the corresponding negative pressure module, the first secondary winding and the corresponding vol