Driving circuit and relevant control method for power switch

Abstract

This invention provides a driving circuit for driving a power switch having a gate terminal, a drain terminal, and a source terminal. The driving circuit includes a driver and a switching time detector. The driver provides a driving current based on a switching signal to charge or discharge the gate terminal, thereby turning the power switch on or off. The driving current has a characteristic, which is one of a duration and a current intensity. The switching time detector determines a switching time based on a gate voltage at the gate terminal, starting at a first point and ending at an end point. The switching time detector updates a recorded voltage based on the switching time. The driver determines the characteristic based on the recorded voltage.

Claims

1. A drive circuit for driving a power switch having a gate terminal, a drain terminal, and a source terminal, the drive circuit comprising: a driver that provides a drive current to the gate terminal to charge or discharge the gate terminal according to a switching signal, thereby turning the power switch on or off, wherein... The drive current has a characteristic, which is either a duration or a current intensity; and a switching time detector determines a switching time based on a gate voltage at the gate terminal, which starts at a first point and ends at an end point, and the switching time detector updates a recorded voltage based on the switching time; wherein the driver determines the characteristic based on the recorded voltage; and the switching signal is a pulse width modulation signal provided by a pulse width modulator, which has a signal frequency, and the driver provides the drive current based on the signal frequency.

2. A drive circuit for driving a power switch having a gate terminal, a drain terminal, and a source terminal, the drive circuit comprising: a driver that provides a drive current to the gate terminal to charge or discharge it according to a switching signal, thereby turning the power switch on or off, wherein... The drive current has a characteristic, which is either a duration or a current intensity; and a switching time detector determines a switching time based on a gate voltage at the gate terminal, which starts at a start point and ends at an end point, and the switching time detector updates a recorded voltage based on the switching time; wherein the driver determines the characteristic based on the recorded voltage; the switching time is a rising switching time, and the end point of the rising switching time is determined by comparing the gate voltage with a first preset voltage; and the power switch can provide a channel current, a current detection signal is used to represent the channel current, and the start point of the rising switching time is determined by comparing the current detection signal with a threshold value.

3. As in the driving circuit of claim 2, wherein, The current detection signal is one of the source voltages at the source terminal.

4. A drive circuit for driving a power switch having a gate terminal, a drain terminal, and a source terminal, the drive circuit comprising: a driver that provides a drive current to the gate terminal according to a switching signal to charge or discharge the gate terminal, thereby turning the power switch on or off, wherein... The drive current has a characteristic, which is either a duration or a current intensity; and a switching time detector determines a switching time based on a gate voltage at the gate terminal, which starts at a start point and ends at an end point, and the switching time detector updates a recorded voltage based on the switching time; wherein the driver determines the characteristic based on the recorded voltage; the switching time is a rising switching time; the end point of the rising switching time is determined by comparing the gate voltage and a first preset voltage; the switching time detector compares the gate voltage and a second preset voltage to determine the start point; and the second preset voltage is lower than the first preset voltage.

5. A drive circuit for driving a power switch having a gate terminal, a drain terminal, and a source terminal, the drive circuit comprising: a driver that provides a drive current to the gate terminal to charge or discharge the gate terminal according to a switching signal, thereby turning the power switch on or off, wherein... The drive current has a characteristic, which is either a duration or a current intensity; and a switching time detector determines a switching time based on a gate voltage at the gate terminal, which starts at a start point and ends at an end point, and the switching time detector updates a recorded voltage based on the switching time; wherein the driver determines the characteristic based on the recorded voltage; the switching time is a falling switching time; and the start point of the falling switching time is determined by comparing the gate voltage with a first preset voltage.

6. As in the driving circuit of claim 5, wherein, A current detection signal represents the current flowing through one channel of the power switch, and the end point of the falling switching time is determined by comparing the current detection signal with a threshold value.

7. As in the driving circuit of claim 5, wherein, The switching time detector compares the gate voltage with a second preset voltage to determine the end point of the falling switching time.

8. A control method for driving a power switch having a gate terminal, a drain terminal, and a source terminal, the control method comprising: providing a drive current according to a switching signal to charge or discharge the gate terminal, thereby turning the power switch on or off, wherein... The drive current has a characteristic, which is either a duration or a current intensity; a switching time is determined based on a gate voltage at the gate terminal, which starts at a first point and ends at an end point; a recorded voltage is updated based on the switching time; and the characteristic is determined based on the recorded voltage; wherein the switching signal is a pulse width modulation signal having a signal frequency, and the control method further includes: providing the drive current based on the signal frequency.

9. A control method for driving a power switch having a gate terminal, a drain terminal, and a source terminal, the control method comprising: providing a drive current according to a switch signal to charge or discharge the gate terminal, thereby turning the power switch on or off, wherein... The drive current has a characteristic, which is one of a duration and a current intensity; a switching time is determined based on a gate voltage at the gate terminal, which starts at a start point and ends at an end point; a recorded voltage is updated based on the switching time; the characteristic is determined based on the recorded voltage; the gate voltage is compared with a first preset voltage to determine one of the start point and the end point; and the gate voltage is compared with a second preset voltage to determine the other of the start point and the end point.

10. A control method for driving a power switch having a gate terminal, a drain terminal, and a source terminal, the control method comprising: providing a drive current according to a switching signal to charge or discharge the gate terminal, thereby turning the power switch on or off, wherein... The drive current has a characteristic, which is one of a duration and a current intensity; a switching time is determined based on a gate voltage at the gate terminal, which starts at a start point and ends at an end point; a recorded voltage is updated based on the switching time; the characteristic is determined based on the recorded voltage; and the gate voltage is compared with a first preset voltage to determine one of the start point and the end point; wherein the power switch can provide a channel current, and the control method further includes: providing a current detection signal to represent the channel current; and comparing the current detection signal with a threshold value to determine the other of the start point and the end point.

11. A control method for driving a power switch having a gate terminal, a drain terminal, and a source terminal, the control method comprising: providing a drive current according to a switching signal to charge or discharge the gate terminal, thereby turning the power switch on or off, wherein... The drive current has a characteristic, which is one of a duration and a current intensity; a switching time is determined based on a gate voltage at the gate terminal, which starts at a first point and ends at an end point; a recorded voltage is updated based on the switching time; and the characteristic is determined based on the recorded voltage; wherein, corresponding to the switching signal, the drive current has a first current intensity and a first duration in a first segment, and a second current intensity and a second duration in a second segment immediately following the first segment, and the control method includes: determining at least one of the second current intensity and the second duration based on the recorded voltage.

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