Grid driving circuit based on comparator control

Abstract

The utility model relates to a gate drive circuit based on comparator control, which comprises a comparator, a first gate driver and a second gate driver, the voltage output end of the comparator and the input ends of the two gate drivers are connected with a first power supply end through resistors, the output end of the first gate driver is connected with the negative input end of the comparator, and the output end of the second gate driver is connected with the negative input end of the comparator. The output end of the second gate driver is connected with the positive input end of the comparator, the negative input end of the comparator is grounded through a capacitor, and the first output end of the first gate driver is connected with the gate driving end of the first to-be-driven MOSFET through a first voltage division circuit. The second output end of the second gate driver is connected with the gate driving end of the second MOSFET to be driven through the second voltage division circuit. The input voltage and the pull-up voltage are adjusted by changing the resistance value, the two gate drivers are turned on when the output voltage of the comparator is at a high level, and the two gate drivers are in a cut-off state when the output voltage of the comparator is at a low level, so that the driving control of the MOSFET to be driven is realized.

Description

Technical Field

[0001] The utility model relates to the field of circuit control, in particular to a gate drive circuit based on comparator control. Background Art

[0002] In the circuit control process, MOSFET gate drive circuits are widely used in switching power supplies, photovoltaic inverters and motor drive systems.

[0003] Existing gate drive circuits are usually equipped with gate drivers to amplify low voltage or low current buffer circuits from microcontrollers or other sources. The gate drive circuit can increase the microcontroller's output PWM wave drive capability, and can drive large-size MOSFETs under smaller signals to achieve digital logic control circuits to control power MOSFETs.

[0004] However, the existing gate drive circuit has a shortcoming: the voltage output to the gate driver cannot be controlled as needed to meet the needs of turning on or off different gate drivers. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a gate drive circuit based on comparator control in view of the above prior art. The gate drive circuit based on comparator control can control the voltage output to the gate driver as required to meet the on or off requirements of different gate drivers.

[0006] The technical solution adopted by the utility model to solve the above technical problems is: a gate drive circuit based on comparator control, characterized in that it includes:

[0007] A comparator having a negative input terminal, a positive input terminal, a voltage output terminal, a first power supply terminal and a second power supply terminal, wherein the first power supply terminal of the comparator is connected to a power supply, the second power supply terminal of the comparator is connected to a ground terminal, the voltage output terminal of the comparator is connected to a first end of a first resistor, and the second end of the first resistor is connected to the first power supply terminal;

[0008] A first gate driver, comprising a first input terminal, a first voltage output terminal, a first power supply terminal and a second power supply terminal, wherein the first input terminal of the first gate driver is connected to the first terminal of a first resistor, the first voltage output terminal of the first gate driver is connected to the first terminal of a second resistor, the second terminal of the second resistor is respectively connected to the negative input terminal of the comparator and the first terminal of a first capacitor, and the second terminal of the first capacitor is connected to the ground terminal; the first power supply terminal of the first gate driver is connected to the second power supply terminal and the first power supply terminal is connected to the ground terminal through a second capacitor connected in series; the second power supply terminal of the first gate driver is connected to the ground terminal and the second power supply terminal is connected to the first power supply terminal of the comparator through a third capacitor connected in series;

[0009] A second gate driver has a second input terminal and a second voltage output terminal, the second input terminal of the second gate driver is connected to the first terminal of the first resistor, the second output terminal of the second gate driver is connected to the first terminal of a third resistor, and the second terminal of the third resistor is connected to the positive input terminal of the comparator;

[0010] The first voltage output terminal of the first gate driver is connected to the gate driving terminal of the first MOSFET to be driven through a first voltage divider circuit; the second voltage output terminal of the second gate driver is connected to the gate driving terminal of the second MOSFET to be driven through a second voltage divider circuit.

[0011] Improved, in the gate driving circuit based on comparator control, the first voltage divider circuit includes:

[0012] a fourth resistor, a first end of which is connected to the first voltage output end of the first gate driver, and a second end of which is connected to the gate driving end of the first MOSFET to be driven;

[0013] A fifth resistor has a first end connected to the first end of the fourth resistor and a second end connected to the second end of the fourth resistor.

[0014] Further, in the gate driving circuit based on comparator control, the second voltage divider circuit includes:

[0015] a sixth resistor, a first end of which is connected to the second voltage output end of the second gate driver, and a second end of which is connected to the gate driving end of the second MOSFET to be driven;

[0016] A first end of the seventh resistor is connected to the first end of the sixth resistor, and a second end of the seventh resistor is connected to the second end of the sixth resistor.

[0017] As a further improvement, in the gate driving circuit based on comparator control, the model of the comparator is MIC6270YM5, and the model of the first gate driver and the second gate driver are both MIC4428YM.

[0018] Improved, in the comparator-controlled gate drive circuit, the resistance of the first resistor is 4.99KΩ, and the voltage of the first power supply terminal is 5V; the resistance of the second resistor is 475KΩ, the capacitance of the first capacitor is 1nF, and the voltage of the second power supply terminal is 12V; the capacitance of the second capacitor is 1μF, the capacitance of the third capacitor is 0.1μF, and the resistance of the third resistor is 475KΩ.

[0019] Further, in the gate driving circuit based on comparator control, the resistance value of the fourth resistor is 3.3Ω, the resistance value of the fifth resistor is 3.3Ω; the resistance value of the sixth resistor is 3.3Ω, and the resistance value of the seventh resistor is 3.3Ω.

[0020] Compared with the prior art, the utility model has the advantages that: in the utility model, the gate drive circuit includes a comparator, a first gate driver and a second gate driver, the voltage output end of the comparator and the input ends of the two gate drivers are connected to the first power supply end through a resistor, the output end of the first gate driver is connected to the negative input end of the comparator, the output end of the second gate driver is connected to the positive input end of the comparator, the negative input end of the comparator is grounded through a capacitor, the first output end of the first gate driver is connected to the gate drive end of the first MOSFET to be driven through a first voltage divider circuit, and the second output end of the second gate driver is connected to the gate drive end of the second MOSFET to be driven through a second voltage divider circuit. By changing the resistance value to adjust the input voltage and the pull-up voltage, the two gate drivers are turned on when the output voltage of the comparator is high, and the two gate drivers are turned off when the output voltage of the comparator is low, thereby realizing the drive control of the MOSFET to be driven. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of a gate drive circuit based on comparator control in an embodiment of the utility model. DETAILED DESCRIPTION

[0022] The present invention will be described in further detail below in conjunction with the accompanying drawings.

[0023] This embodiment provides a gate drive circuit based on comparator control. Figure 1 As shown, the gate driving circuit based on comparator control of this embodiment includes:

[0024] The comparator U23 has a negative input terminal 11, a positive input terminal 12, a voltage output terminal 13, a first power supply terminal 14 and a second power supply terminal 15. The first power supply terminal 14 of the comparator U23 is connected to a power supply VCC, the second power supply terminal 15 of the comparator U23 is connected to a ground terminal GND, the voltage output terminal 13 of the comparator U23 is connected to a first end of a first resistor R81, and the second end of the first resistor R81 is connected to a first power supply terminal V1;

[0025] The first gate driver U27B has a first input terminal 21, a first voltage output terminal 22, a first power supply electrode 23 and a second power supply electrode 24. The first input terminal 21 of the first gate driver U27B is connected to the first end of the first resistor R81, the first voltage output terminal 22 of the first gate driver U27B is connected to the first end of a second resistor R84, the second end of the second resistor R84 is respectively connected to the negative input terminal 11 of the comparator U23 and the first electrode of a first capacitor C42, and the second electrode of the first capacitor C42 is connected to the ground terminal GND; the first power supply electrode 23 of the first gate driver U27B is connected to the second power supply terminal V2 and the first power supply electrode 23 is connected to the ground terminal GND through a second capacitor C65 connected in series; the second power supply electrode 24 of the first gate driver U27B is connected to the ground terminal GND and the second power supply electrode 24 is connected to the first power supply terminal 14 of the comparator U23 through a third capacitor C56 connected in series;

[0026] The second gate driver U27A has a second input terminal 31 and a second voltage output terminal 32, the second input terminal 31 of the second gate driver U27A is connected to the first end of the first resistor R81, the second output terminal 32 of the second gate driver U27A is connected to the first end of a third resistor R83, and the second end of the third resistor R83 is connected to the positive input terminal of the comparator U23;

[0027] Among them, the first voltage output terminal 22 of the first gate driver U27B is connected to the gate driving terminal G1 of the first MOSFET to be driven through the first voltage divider circuit X; the second voltage output terminal 32 of the second gate driver U27A is connected to the gate driving terminal G2 of the second MOSFET to be driven through the second voltage divider circuit Y.

[0028] Specifically in this embodiment, the first voltage divider circuit X here includes a fourth resistor R88 and a fifth resistor R87 connected in parallel with each other, a first end of the fourth resistor R88 is connected to the first voltage output terminal 22 of the first gate driver U27B, and a second end of the fourth resistor R88 is connected to the gate drive terminal G1 of the first MOSFET to be driven; a first end of the fifth resistor R87 is connected to the first end of the fourth resistor R88, and a second end of the fifth resistor R87 is connected to the second end of the fourth resistor R88.

[0029] More specifically in this embodiment, the second voltage divider circuit Y here includes a sixth resistor R89 ​​and a seventh resistor R86 connected in parallel with each other, the first end of the sixth resistor R89 ​​is connected to the second voltage output terminal 32 of the second gate driver U27A, and the second end of the sixth resistor R89 ​​is connected to the gate drive terminal G2 of the second MOSFET to be driven; the first end of the seventh resistor R86 is connected to the first end of the sixth resistor R89, and the second end of the seventh resistor R86 is connected to the second end of the sixth resistor R89.

[0030] As for the specific parameter settings of each electrical component in this embodiment, the model of the above-mentioned comparator U23 is MIC6270YM5, and the models of the first gate driver U27B and the second gate driver U27A are both MIC4428YM. In addition, the resistance of the first resistor R81 is 4.99KΩ, the resistance of the second resistor R84 is 475KΩ, the resistance of the third resistor R83 is 475KΩ, the resistance of the fourth resistor R88 is 3.3Ω, the resistance of the fifth resistor R87 is 3.3Ω, the resistance of the sixth resistor R89 ​​is 3.3Ω, and the resistance of the seventh resistor R86 is 3.3Ω; the voltage of the first power supply terminal V1 is 5V, and the voltage of the second power supply terminal V2 is 12V; the capacitance of the first capacitor C42 is 1nF, the capacitance of the second capacitor C65 is 1μF, and the capacitance of the third capacitor C56 is 0.1μF.

[0031] The following combination Figure 1 , the principle of the gate drive circuit based on comparator control in this embodiment is explained:

[0032] By adjusting the resistance values ​​of the third resistor R83 and the second resistor R84, the input differential voltage of the comparator U23 can be changed, that is, the input voltage of the positive input terminal 12 and the input voltage of the negative input terminal 11 are changed, thereby changing the output voltage of the comparator U23;

[0033] When the input voltage of the positive input terminal 12 of the comparator U23 is greater than the input voltage of the negative input terminal 11, the comparator U23 outputs a high level, so that the first gate driver U27B and the second gate driver U27A are both turned on, and then the first gate driver U27B drives the gate of the first MOSFET to be driven and the second gate driver U27A drives the gate of the second MOSFET to be driven;

[0034] When the input voltage of the positive input terminal 12 of the comparator U23 is less than the input voltage of the negative input terminal 11, the comparator U23 outputs a low level, and the first gate driver U27B and the second gate driver U27A are both in the cut-off state, thereby having a hysteresis effect.

[0035] Although the preferred embodiments of the present invention are described in detail above, it should be clearly understood that the present invention may be modified and varied by those skilled in the art. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Gate drive circuit based on comparator control, It is characterized in that include: A comparator (U23) having a negative input terminal (11), a positive input terminal (12), a voltage output terminal (13), a first power supply terminal (14) and a second power supply terminal (15); the first power supply terminal (14) of the comparator (U23) is connected to a power supply (VCC); the second power supply terminal (15) of the comparator (U23) is connected to a ground terminal (GND); the voltage output terminal (13) of the comparator (U23) is connected to a first end of a first resistor (R81); and the second end of the first resistor (R81) is connected to a first power supply terminal (V1); A first gate driver (U27B) has a first input terminal (21), a first voltage output terminal (22), a first power supply terminal (23) and a second power supply terminal (24), wherein the first input terminal (21) of the first gate driver (U27B) is connected to a first end of a first resistor (R81), the first voltage output terminal (22) of the first gate driver (U27B) is connected to a first end of a second resistor (R84), and the second end of the second resistor (R84) is respectively connected to a negative input terminal (11) of a comparator (U23) and a first capacitor (C42). ), the second electrode of the first capacitor (C42) is connected to the ground terminal (GND); the first power supply electrode (23) of the first gate driver (U27B) is connected to the second power supply terminal (V2), and the first power supply electrode (23) is connected to the ground terminal (GND) through a second capacitor (C65) connected in series; the second power supply electrode (24) of the first gate driver (U27B) is connected to the ground terminal (GND), and the second power supply electrode (24) is connected to the first power supply terminal (14) of the comparator (U23) through a third capacitor (C56) connected in series; A second gate driver (U27A) has a second input terminal (31) and a second voltage output terminal (32), wherein the second input terminal (31) of the second gate driver (U27A) is connected to the first terminal of the first resistor (R81), the second voltage output terminal (32) of the second gate driver (U27A) is connected to the first terminal of a third resistor (R83), and the second terminal of the third resistor (R83) is connected to the positive input terminal of the comparator (U23); The first voltage output terminal (22) of the first gate driver (U27B) is connected to the gate driving terminal (G1) of the first MOSFET to be driven through a first voltage divider circuit (X); and the second voltage output terminal (32) of the second gate driver (U27A) is connected to the gate driving terminal (G2) of the second MOSFET to be driven through a second voltage divider circuit (Y).

2. The comparator-controlled gate drive circuit according to claim 1, It is characterized in that The first voltage divider circuit (X) comprises: a fourth resistor (R88), a first end of which is connected to the first voltage output end (22) of the first gate driver (U27B), and a second end of which is connected to the gate drive end (G1) of the first MOSFET to be driven; A fifth resistor (R87) has a first end connected to the first end of the fourth resistor (R88), and a second end of the fifth resistor (R87) is connected to the second end of the fourth resistor (R88).

3. The comparator-controlled gate drive circuit according to claim 2, It is characterized in that The second voltage divider circuit (Y) comprises: a sixth resistor (R89), a first end of which is connected to the second voltage output end (32) of the second gate driver (U27A), and a second end of which is connected to the gate drive end (G2) of the second MOSFET to be driven; A first end of the seventh resistor (R86) is connected to the first end of the sixth resistor (R89), and a second end of the seventh resistor (R86) is connected to the second end of the sixth resistor (R89).

4. The comparator-controlled gate drive circuit according to claim 3, It is characterized in that The model of the comparator (U23) is MIC6270YM5, and the model of the first gate driver (U27B) and the second gate driver (U27A) are both MIC4428YM.

5. The comparator-controlled gate drive circuit according to claim 3, It is characterized in that The resistance of the first resistor (R81) is 4.99KΩ, and the voltage of the first power supply terminal (V1) is 5V; the resistance of the second resistor (R84) is 475KΩ, the capacitance of the first capacitor (C42) is 1nF, and the voltage of the second power supply terminal (V2) is 12V; the capacitance of the second capacitor (C65) is 1μF, the capacitance of the third capacitor (C56) is 0.1μF, and the resistance of the third resistor (R83) is 475KΩ.

6. The comparator-controlled gate drive circuit according to claim 5, It is characterized in that The resistance value of the fourth resistor (R88) is 3.3Ω, the resistance value of the fifth resistor (R87) is 3.3Ω; the resistance value of the sixth resistor (R89) is 3.3Ω, and the resistance value of the seventh resistor (R86) is 3.3Ω.

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