Design Of An Input Pulse Filter Circuit For High Voltage Gate Driver Chip

The high-voltage gate driver chip has become a core component of the motor control system with the miniaturization of the motor drive system.In the drive system applications,it is usually necessary to integrate filter circuits inside the driver chip to suppress input signal noise.However,when the pulse width of the input signal is small,the output signal of the RC pulse filter circuit will be seriously distorted,resulting in narrow pulse noise.The transmission of the narrow pulse signal to the rear stage circuit will lead to an error in the output signal of the chip,causing the power transistor of the latter stage to be opened or turned off by mistake,or even causing the power tube to pass through,thereby causing damage to the power tube.Therefore,it is of great significance to do the research on the low-distortion input pulse filter circuit and it will greatly improve the reliability of the driver chip.Firstly,the application background and working principle of the high-voltage gate driver chip are analyzed in detail in this thesis,then the traditional input pulse filter circuit technology is deeply studied in.this thesis It is found that the fundamental reason for the pulse width distortion in the conventional input pulse filter circuit is that it cannot guarantee that the initial voltage is the power supply voltage when the capacitor is discharged.The falling edge delay and rising edge delay of the output signal of the filter circuit are not equal.To solve this problem,a low-distortion input pulse filter circuit based on dual-circuit charge delay circuit is designed in this thesis.When the input signal pulse width is smaller than the filter width,the input signal will be filtered out.When the pulse width of the input signal is greater than the filter width,the two-way charging delay circuit is used to delay the two edges of the input signal respectively to ensure that the transmission delay of the rising edge and the falling edge of the input signal is the same.Finally,the logic signal processing circuit is used to restore the two delayed signals to normal signals,ensuring low distortion of the signal transmission.In this thesis,the input pulse filter circuit was realized based on the 0.5?m 600 V bulk silicon Bipolar-CMOS-DMOS(BCD)process,and the layout of the circuit was designed,at last the layout was taped out and tested.The test results show that,the input pulse filter circuit designed in this thesis filters out the input positive and negative narrow pulse noise signals effectively and the filtering accuracy is better than 1ns.When the normal working signal is transmitted,the pulse width distortion of the output signal of the filter circuit is less than 2%.All the results meet the design requirements.