Self-adaptive gate drive detection circuit

Abstract

The utility model discloses a self-adaptive gate drive detection circuit, which relates to the technical field of electronic circuits, aims to solve the problem of overhigh invalid power loss of a drive motor, and comprises a logic circuit module connected with a level conversion module, the level conversion module is connected with a gate drive module, and the gate drive module is connected with a power supply module. The grid driving module is connected with a phase voltage detection module, the phase voltage detection module is connected with the logic circuit module, and the grid driving module is connected with a direct current motor. According to the self-adaptive gate drive detection circuit, self-adaptive gate drive is adopted, and the conduction and turn-off delay of an external MOS (Metal Oxide Semiconductor) tube is reduced by adjusting the magnitude of charging and discharging current before and after the arrival of a Miller platform, so that a driver can meet the harsh EMI (Electro-Magnetic Interference) requirement, and the invalid power loss of a driving motor is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of electronic circuit technology, and specifically relates to an adaptive gate drive detection circuit. Background Technology

[0002] In modern electronic devices, the drive control of MOSFETs is crucial. However, existing MOSFET gate drive technologies have several problems. Due to the Miller effect, a plateau voltage forms during MOSFET gate drive, leading to longer switching times and increased switching losses, which negatively impacts the normal operation of the MOSFET. Furthermore, electromagnetic interference causes ineffective power loss in the drive motor. Excessive charging and discharging times before and after the Miller plateau increase chip power consumption, causing the chip temperature to rise excessively during motor operation, thus affecting normal chip operation.

[0003] For example, Chinese patent CN115603549B discloses an adaptive hierarchical driving method and circuit for a MOSFET. The method involves acquiring the drain-source voltage of the MOSFET, determining a detection threshold based on the acquired steady-state voltage values ​​after turn-on and complete turn-off, a preset fixed bias, and a preset bias calibration voltage, superimposing the preset bias voltage onto the drain-source voltage, and comparing this with the detection threshold to determine the switching transition state of the MOSFET. Based on the switching transition state, a preset basic drive current configuration, and preset drive state control information, a drive current code is obtained. A D / A conversion module is then used to convert the drive current code into a drive current signal. The drive current is output to the MOSFET gate to achieve hierarchical driving, reduce switching losses, and improve system efficiency. However, the Chinese patent with publication number CN115603549B has a relatively complex hardware structure and high implementation cost. It also requires the first acquisition of drain-source voltage, and the subsequent multi-level processing such as bias adjustment, multiplexing, and comparison before generating the drive current code and finally outputting the drive current through D / A conversion. The response speed is relatively slow. In addition, the Chinese patent with publication number CN115603549B mainly focuses on reducing switching losses, with few direct control and optimization measures for EMI, resulting in weak EMI control capabilities. Utility Model Content

[0004] To address the problem of excessive ineffective power loss in drive motors, this invention proposes an adaptive gate drive detection circuit. By employing adaptive gate drive, the charging and discharging current is adjusted before and after the Miller plateau, reducing the turn-on and turn-off delays of the external MOSFET. This enables the driver to meet stringent EMI requirements and reduces ineffective power loss in the drive motor.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: an adaptive gate drive detection circuit, comprising a logic circuit module connected to a level conversion module, the level conversion module connected to a gate drive module, the gate drive module connected to a phase voltage detection module, the phase voltage detection module connected to the logic circuit module, and a DC motor connected to the gate drive module and the phase voltage detection module.

[0006] In this technical solution, by adjusting the magnitude of the charging and discharging current before and after the arrival of the Miller platform, the turn-on and turn-off delay of the external MOSFET is reduced, enabling the driver to meet stringent EMI requirements.

[0007] Preferably, the input terminal of the logic circuit module is connected to the output terminal of the phase voltage detection module, and the output terminal of the logic circuit module is connected to the input terminal of the gate drive module through a level conversion module. The level conversion module raises the input signal from a low voltage level to a high voltage level to control the gate drive module.

[0008] Preferably, the output terminal of the gate drive module is connected to the input terminal of the phase voltage detection module, and the input terminal of the phase voltage detection module is connected to the load inside the DC motor, the phase voltage and the switch node threshold voltage. The gate drive module is used to realize adjustable gate drive current control to adjust the VDS slew rate of the DC motor's MOSFET.

[0009] Preferably, the gate driving module includes a high-side gate driving module and a low-side gate driving module, which are respectively connected to the gate of the high-side MOSFET M5 and the gate of the low-side MOSFET M6 of the DC motor.

[0010] Preferably, the phase voltage detection module consists of a first unit and a second unit. The first unit includes a comparator C1, and the second unit includes a comparator C2. The phase voltage detection module is used for phase voltage VSH detection.

[0011] Preferably, the non-inverting input terminals of comparators C1 and C2 are connected to the phase voltage of the DC motor, the output terminals of comparators C1 and C2 are connected to the logic circuit module, the inverting output terminal of comparator C1 is connected to the high voltage threshold signal of the switching node, and the inverting output terminal of comparator C2 is connected to the low voltage threshold signal of the switching node. The phase voltage VSH is used as the switching node detection signal to realize closed-loop control.

[0012] Preferably, the gate drive module includes a plurality of MOSFETs, and the MOSFETs are connected to a plurality of drive current sources. The high-side gate drive module includes at least MOSFETs M1 and M2, and the low-side gate drive module includes at least MOSFETs M3 and M4.

[0013] Preferably, the gates of MOSFETs M1 and M2 are connected to a level conversion module, the source of MOSFET M1 and the drain of MOSFET M2 are connected, the drain of MOSFET M1 is connected to a first power supply, the source of MOSFET M2 is connected to the phase voltage of a DC motor, a first drive current source is connected between the first power supply and the source of M1, and a second drive current source is connected between the drain and the source of MOSFET M2.

[0014] Preferably, the gates of MOSFETs M3 and M4 are connected to a level conversion module, the source of MOSFET M3 and the drain of MOSFET M4 are connected, the drain of MOSFET M3 is connected to a first power supply, the source of MOSFET M4 is connected to a power ground line, a third drive current source is connected between the first power supply and the source of M3, and a fourth drive current source is connected between the drain and the source of MOSFET M4.

[0015] Preferably, the source of MOSFET M1 is connected to the gate of the high-side MOSFET M5 of the DC motor, and the source of MOSFET M3 is connected to the gate of the low-side MOSFET M6 of the DC motor.

[0016] The beneficial effects of this invention are: by adaptively adjusting the gate drive current to achieve segmented driving, the switching losses of the MOSFET are effectively reduced, and the efficiency and reliability of the circuit are improved; it can meet stringent EMI requirements, reduce the impact of electromagnetic interference on the motor drive system, and improve the performance and stability of the entire system. Attached Figure Description

[0017] Figure 1 This is a block diagram of an adaptive gate drive detection circuit according to the present invention.

[0018] Figure 2 This is a circuit diagram of an adaptive gate drive detection circuit according to the present invention.

[0019] Figure 3 This is a schematic diagram illustrating the working principle of an adaptive gate drive detection circuit according to this utility model.

[0020] Figure reference numerals: Phase voltage VSH; High voltage threshold signal VSH_H for VSH switching node; Low voltage threshold signal VSH_L for VSH switching node; High-side gate drive signal GH; Low-side gate drive signal GL; High-side source voltage signal SH; Power ground PGND; First power supply VVCP; Second power supply VBAT; Ground signal GND; Gate drive pull-up current IDRVP; Gate drive sink current IDRVN; Pre-charge current IPRE_CHR; Pre-discharge current IPRE_DCHR; Post-charge current IPST_CHR; Post-discharge current IPST_DCHR. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only one preferred embodiment of this utility model and are only used to explain this utility model. They do not limit the scope of protection of this utility model. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0022] Example 1

[0023] This embodiment provides an adaptive gate drive detection circuit, such as Figure 1 As shown, it includes a logic circuit module, a level conversion module, a gate drive module, and a phase voltage detection module.

[0024] The input terminal of the logic circuit module is connected to the output terminal of the phase voltage detection module to receive the threshold detection feedback signal from the phase voltage detection module.

[0025] Based on these signals, the logic circuit module generates corresponding control signals through internal logic operations and judgments to control the gate drive signal and adjust the drive current of the gate drive module.

[0026] The output of the logic circuit module is connected to the input of the gate drive module through a level conversion module to ensure that the control signal can be accurately transmitted to the gate drive module.

[0027] The main function of the level conversion module is to convert the low-voltage level signal output by the logic circuit module into a high-voltage level signal to meet the operating voltage requirements of the gate drive module.

[0028] The input terminal of the level conversion module is connected to the output terminal of the logic circuit module to receive low-voltage control signals; the output terminal is connected to the input terminal of the gate drive module to provide the gate drive module with a high-voltage signal after level conversion.

[0029] The level conversion module enables level matching between the logic circuit module and the gate drive module, ensuring accurate signal transmission and normal operation of the gate drive module.

[0030] The gate drive module is a key component that directly controls the gate voltage of the MOSFET, and its output is connected to the gate of the MOSFET in the DC motor.

[0031] The gate drive module adjusts its own drive current according to the high-voltage level control signal provided by the level conversion module, thereby achieving precise control of the gate voltage of the MOSFET.

[0032] By adjusting the magnitude of the drive current, the gate drive module can provide different charging and discharging currents before and after the Miller plateau, thereby reducing the turn-on and turn-off delays of the MOSFET and improving the switching speed and efficiency of the motor.

[0033] In this embodiment, the gate drive module is divided into a high-side gate drive module and a low-side gate drive module. The input terminals of the high-side gate drive module and the low-side gate drive module are each connected to an independent level conversion module, and the output terminals are connected to a DC motor to realize adjustable gate drive current control, so as to adjust the VDS slew rate of the high-side MOSFET and the low-side MOSFET of the DC motor.

[0034] Figure 2 The schematic diagram of the adaptive gate drive detection circuit in this embodiment includes logic circuits, level conversion, comparator C1, comparator C2, MOS transistor M1, MOS transistor M2, MOS transistor M3, MOS transistor M4, drive current source I1, drive current source I2, drive current source I3, and drive current source I4.

[0035] Specifically, the high-side gate drive module includes MOSFETs M1 and M2. The gates of MOSFETs M1 and M2 are connected to a level conversion module. The source of MOSFET M1 and the drain of MOSFET M2 are connected. The drain of MOSFET M1 is connected to a first power supply. The source of MOSFET M2 is connected to the phase voltage of a DC motor. A first drive current source I1 is connected between the first power supply and the source of M1. A second drive current source I2 is connected between the drain and the source of MOSFET M2.

[0036] During the switch-off period, MOSFET M1 can maintain a high-side gate pull-up current, and MOSFET M2 can maintain a high-side gate strong pull-down current; during the switch-on period, the first drive current source I1 can generate a high-side gate pull-up current, and the second drive current source I2 can generate a high-side gate sink current.

[0037] The low-side gate drive module includes MOSFETs M3 and M4. The gates of MOSFETs M3 and M4 are connected to a level conversion module. The source of MOSFET M3 and the drain of MOSFET M4 are connected. The drain of MOSFET M3 is connected to a first power supply. The source of MOSFET M4 is connected to a power ground line. A third drive current source I3 is connected between the first power supply and the source of M3. A fourth drive current source I4 is connected between the drain and source of MOSFET M4.

[0038] During the switch-off period, MOSFET M3 can maintain the low-side gate pull-up current, and MOSFET M4 can maintain the low-side gate strong pull-down current; during the switch-on period, the third drive current source I3 can generate the low-side gate pull-up current, and the fourth drive current source I4 can generate the low-side gate sink current.

[0039] Among them, the first power supply VVCP is the power supply for the gate drive module, the second power supply VBAT is the power supply for the DC motor, GND is the ground signal, IDRVP is the gate drive pull-up current, IDRVN is the gate drive sink current, VSH_H and VSH_L are the high voltage threshold signal and low voltage threshold signal of the VSH switch node, respectively.

[0040] The source of MOSFET M1 is connected to the gate of the high-side MOSFET M5 of the DC motor, and the source of MOSFET M3 is connected to the gate of the low-side MOSFET M6 of the DC motor.

[0041] In this embodiment, the drive pull-down current can be adaptively adjusted to reduce the turn-on and turn-off delay of the external MOSFET, enabling the driver to meet stringent EMI requirements.

[0042] The phase voltage detection module has one input terminal connected to the phase voltage VSH and the other terminal connected to the switch node thresholds VSH_H and VSH_L for phase voltage VSH detection.

[0043] The phase voltage detection module can monitor the phase voltage VSH of the DC motor in real time and compare it with the preset high voltage threshold signal VSH_H and low voltage threshold signal VSH_L.

[0044] In this embodiment, the phase voltage detection module consists of two comparators C1 and C2. The non-inverting input terminals of comparator C1 and C2 are both connected to the phase voltage VSH of the DC motor. The inverting input terminal of comparator C1 is connected to the high voltage threshold signal VSH_H, and the inverting input terminal of comparator C2 is connected to the low voltage threshold signal VSH_L.

[0045] Based on the comparison results of VSH with VSH_H and VSH_L, comparators C1 and C2 output corresponding high and low level signals. These signals are transmitted to the logic circuit module as threshold detection feedback signals, providing a basis for the control decision of the logic circuit module.

[0046] The working principle of an adaptive gate drive detection circuit in this embodiment will be described in detail below.

[0047] The gate drive module adjusts the drive current according to the control signal, such as Figure 3 As shown.

[0048] Before the MOS transistor QGD Miller plateau arrives, increase the pre-charge current IPRE_CHR and the pre-discharge current IPRE_DCHR to reduce the on and off delays of the external MOS transistor, enabling the driver to achieve a wider range of duty cycle resolution while still meeting stringent EMI requirements.

[0049] After the MOS transistor QGD Miller plateau, increase the post-charge current IPST_CHR and the post-discharge current IPST_DCHR to reach the low-resistance or off state more quickly, achieving precise control of the MOS transistor switching process, improving the performance and efficiency of the motor, and minimizing power loss.

[0050] The switching node that adjusts the charge and discharge current magnitudes before and after the Miller plateau arrives measures the MOS transistor switching node voltage VSH and then increases the gate current after exceeding an appropriate threshold.

[0051] Comparators C1 and C2 respectively implement the determination of the VSH_H and VSH_L node voltages.

[0052] During the operation of the circuit, the phase voltage VSH slowly rises from zero.

[0053] When 0 < VSH < VSH_L, both comparators C1 and C2 output a low level.

[0054] When VSH_L < VSH < VSH_H, comparator C1 outputs a low level and comparator C2 outputs a high level.

[0055] When VSH_H < VSH, both comparators C1 and C2 output a high level.

[0056] The logic circuit controls the drive current of the gate drive circuit through the threshold detection feedback signal to achieve a negative feedback closed loop.

[0057] Specifically, after receiving these signals, the logic circuit module generates corresponding control signals according to the preset logical relationship and transmits them to the gate drive module through the level conversion module.

[0058] An adaptive gate drive detection circuit provided in this embodiment can achieve hierarchical drive by adaptively adjusting the gate drive current, effectively reducing the switching loss of the MOS transistor and improving the operating efficiency of the motor.

[0059] At the same time, it can use the phase voltage VSH as a feedback signal to form a closed-loop control system, real-time monitor and adjust the gate drive process, ensuring that the motor can operate stably and efficiently under various working conditions.

[0060] In addition, the structure design of the adaptive gate drive detection circuit provided in this embodiment is reasonable, and each module works in coordination with each other, having good reliability and versatility, and can be widely applied to various motor drive systems.

[0061] Embodiment 2

[0062] Taking a small DC motor drive system as an example, this embodiment further elaborates on the technical solution of the present invention. This small DC motor drive system uses an adaptive gate drive detection circuit of the present invention.

[0063] In this embodiment, the adaptive gate drive detection circuit is applied to a small DC motor drive system with a rated voltage of 24V.

[0064] The circuit includes a logic circuit module, a level conversion module, a gate drive module, and a phase voltage detection module.

[0065] The logic circuit module uses a CMOS logic circuit, the level conversion module uses a dedicated level conversion chip, and the gate drive module consists of a high-side and a low-side drive circuit, each containing two MOS transistors and corresponding drive current sources. Among them, MOS transistors M1 and M2 are used for the high side, and MOS transistors M3 and M4 are used for the low side.

[0066] The phase voltage detection module includes two comparators C1 and C2, which are used to detect the motor phase voltage VSH and compare it with the set high and low voltage thresholds VSH_H = 18V and VSH_L = 6V.

[0067] When the motor starts, the phase voltage VSH gradually rises.

[0068] In the initial stage, that is, when 0 < VSH < 6V, both comparators C1 and C2 output low levels. After receiving the signal, the logic circuit module controls the gate drive module to provide a relatively small pre-charge current IPRE_CHR = 50mA and pre-discharge current IPRE_DCHR = 50mA, so that the MOSFET starts to conduct.

[0069] As VSH continues to rise to 6V < VSH < 18V, comparator C2 outputs a high level. The logic circuit module adjusts the control signal, increases the pre-charge current IPRE_CHR = 100mA and pre-discharge current IPRE_DCHR = 100mA, speeds up the conduction speed of the MOSFET, and reduces the conduction delay.

[0070] When VSH exceeds 18V, both comparators C1 and C2 output high levels. The logic circuit module further adjusts, increases the post-charge current IPST_CHR = 150mA and post-discharge current IPST_DCHR = 150mA, so that the MOSFET quickly reaches the low-resistance state and reduces the switching loss.

[0071] An adaptive gate drive detection circuit in this embodiment employs adaptive gate drive current regulation, which achieves graded drive by adjusting the magnitude of the charging and discharging current before and after the Miller plateau.

[0072] Specifically, before the Miller plateau arrives, the pre-charge current IPRE_CHR and pre-discharge current IPRE_DCHR are increased to reduce the turn-on and turn-off delays of the external MOSFET; after the Miller plateau, the post-charge current IPST_CHR and post-discharge current IPST_DCHR are increased to enable the MOSFET to reach low resistance or turn-off state more quickly, minimizing power loss.

[0073] The adaptive gate drive detection circuit in this embodiment is implemented using closed-loop control. The phase voltage VSH is used as the detection signal of the switching node. Comparators C1 and C2 compare VSH with the high and low voltage thresholds VSH_H and VSH_L. The logic circuit controls the drive current of the gate drive circuit according to the comparison result, forming a negative feedback closed loop to achieve precise control of the gate drive process.

[0074] By adaptively adjusting the gate drive current, the switching speed of the motor is significantly increased, switching losses are reduced by about 30%, and motor operating efficiency is improved by about 15%. At the same time, because the circuit can adjust the drive current in real time according to changes in phase voltage, the stability and reliability of the motor under different load conditions are significantly improved, effectively avoiding motor speed fluctuations and unstable operation caused by switching delays.

[0075] Example 3

[0076] This embodiment takes an electric vehicle motor drive system as an example to further illustrate the technical solution of this utility model. The electric vehicle motor drive system adopts an adaptive gate drive detection circuit of this utility model.

[0077] In an electric vehicle motor drive system, an adaptive gate drive detection circuit is applied to a high-voltage DC motor with a rated voltage of 300V.

[0078] The circuit structure is similar to that of Example 2, but the parameters and performance requirements of each module are higher.

[0079] The logic circuit module uses a high-performance digital signal processor (DSP) to implement more complex control algorithms.

[0080] The level conversion module can convert low-voltage signals into high-voltage signals up to 400V to meet the high voltage requirements of motors.

[0081] The MOSFETs and drive current sources in the gate drive module are all selected from devices that can withstand high voltage and high current to ensure stable operation under harsh working conditions.

[0082] The high and low voltage thresholds VSH_H and VSH_L of the phase voltage detection module are set to 280V and 200V respectively, based on the characteristics of the motor.

[0083] When an electric vehicle starts and accelerates, the motor phase voltage VSH changes rapidly.

[0084] When VSH is below 200V, comparator C2 outputs a low level, and the logic circuit module controls the gate drive module to provide a small pre-charge current and pre-discharge current, so that the MOSFET can be turned on smoothly.

[0085] As VSH rises to between 200V and 280V, comparator C2 outputs a high level, and the logic circuit module increases the pre-charge and pre-discharge current, accelerating the switching speed of the MOSFET to meet the high power requirements of the motor during acceleration.

[0086] When VSH exceeds 280V, comparator C1 also outputs a high level. The logic circuit module further increases the post-charging and post-discharging current to ensure that the MOSFET quickly reaches a low resistance state, reducing switching losses and improving motor efficiency.

[0087] During deceleration or braking, VSH decreases, and the circuit correspondingly reduces the drive current to achieve smooth shutdown control.

[0088] The adaptive gate drive detection circuit in this embodiment is applied to an electric vehicle motor drive system, significantly improving the motor's control accuracy and dynamic performance. The motor's switching losses are reduced by approximately 35%, efficiency is increased by approximately 20%, and the driving range of the electric vehicle is effectively extended.

[0089] Meanwhile, the circuit's adaptive adjustment function enables the motor to maintain optimal operating conditions under different operating conditions, improving driving smoothness and comfort.

[0090] Furthermore, because the circuit can effectively reduce the switching delay and power loss of MOSFETs, the reliability and service life of the motor are also greatly improved, reducing the maintenance cost and failure rate of electric vehicles.

Claims

1. An adaptive gate drive detection circuit, characterized in that, The system includes a logic circuit module connected to a level conversion module, a level conversion module connected to a gate driving module, a gate driving module connected to a phase voltage detection module, a phase voltage detection module connected to the logic circuit module, and a DC motor connected to the gate driving module and the phase voltage detection module.

2. The adaptive gate drive detection circuit according to claim 1, characterized in that, The input terminal of the logic circuit module is connected to the output terminal of the phase voltage detection module, and the output terminal of the logic circuit module is connected to the input terminal of the gate drive module through a level conversion module.

3. The adaptive gate drive detection circuit according to claim 1, characterized in that, The input terminals of the phase voltage detection module are connected to the DC motor and the internal preset threshold signal, respectively, to obtain the phase voltage of the DC motor and the threshold voltage of the switching node.

4. An adaptive gate drive detection circuit according to claim 1 or 3, characterized in that, The gate driving module includes a high-side gate driving module and a low-side gate driving module, which are respectively connected to the gate of the high-side MOSFET M5 and the gate of the low-side MOSFET M6 of the DC motor.

5. The adaptive gate drive detection circuit according to claim 1, characterized in that, The phase voltage detection module consists of a first unit and a second unit. The first unit includes a comparator C1, and the second unit includes a comparator C2.

6. The adaptive gate drive detection circuit according to claim 5, characterized in that, The non-inverting input terminals of comparators C1 and C2 are connected to the phase voltage of the DC motor. The output terminals of comparators C1 and C2 are connected to the logic circuit module. The inverting output terminal of comparator C1 is connected to the high voltage threshold signal of the switching node, and the inverting output terminal of comparator C2 is connected to the low voltage threshold signal of the switching node.

7. The adaptive gate drive detection circuit according to claim 4, characterized in that, The gate driving module includes a plurality of MOS transistors, each MOS transistor being connected to a plurality of driving current sources. The high-side gate driving module includes at least MOS transistors M1 and M2, and the low-side gate driving module includes at least MOS transistors M3 and M4.

8. The adaptive gate drive detection circuit according to claim 7, characterized in that, The gates of MOSFETs M1 and M2 are connected to a level conversion module. The source of MOSFET M1 and the drain of MOSFET M2 are connected. The drain of MOSFET M1 is connected to a first power supply. The source of MOSFET M2 is connected to the phase voltage of a DC motor. A first drive current source is connected between the first power supply and the source of M1. A second drive current source is connected between the drain and source of MOSFET M2.

9. The adaptive gate drive detection circuit according to claim 7, characterized in that, The gates of MOSFETs M3 and M4 are connected to a level conversion module. The source of MOSFET M3 and the drain of MOSFET M4 are connected. The drain of MOSFET M3 is connected to a first power supply. The source of MOSFET M4 is connected to a power ground line. A third drive current source is connected between the first power supply and the source of M3. A fourth drive current source is connected between the drain and the source of MOSFET M4.

10. The adaptive gate drive detection circuit according to claim 7, characterized in that, The source of MOSFET M1 is connected to the gate of the high-side MOSFET M5 of the DC motor, and the source of MOSFET M3 is connected to the gate of the low-side MOSFET M6 of the DC motor.

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