Short-circuit protection method for transistor in control circuit

A short-circuit protection and control circuit technology, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problems that cannot meet the short-circuit protection time requirements of MOSFETs, long response time of Hall sensors, etc., and achieve good linearity, high accuracy, The circuit achieves simple effects

Inactive Publication Date: 2015-05-06
CHANGZHOU GLOBE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the Hall sensor itself has a long response time, which cannot meet the short-circuit protection time requirements of the MOSFET, and can only be used for over-current detection.

Method used

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  • Short-circuit protection method for transistor in control circuit

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Embodiment Construction

[0014] Specific embodiments of the present invention will be described below in conjunction with the accompanying drawings.

[0015] see figure 1 As shown, it shows a schematic circuit diagram of an embodiment of the present invention. In this embodiment, the control circuit is a control circuit for controlling a motor of a high pressure washer. Such as figure 1 As shown, six MOSFET transistors are used in the control circuit to form a three-phase bridge drive circuit. Each phase drive circuit includes two MOSFET transistors connected in series, and the two MOSFET transistors connected in series are connected to the positive and negative poles of the power supply. One phase coil is energized to drive the motor to rotate. The specific principle and working method of the three-phase bridge drive circuit composed of MOSFET transistors will not be described in detail here.

[0016] Such as figure 1 As shown, when the circuit is abnormal, the positive and negative electrodes ...

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Abstract

The invention provides a short-circuit protection method for a transistor in a control circuit. The short-circuit protection method comprises the steps of acquiring induced electromotive force U at two ends of a section of a loop inductor of the circuit where the transistor is located, comparing the induced electromotive force U with pre-determined reference voltage Vref, enabling a transistor short-circuit protection circuit to output a control signal for controlling a drive signal of the transistor to change if the induced electromotive force U at two ends of the loop inductor is larger than the pre-determined reference voltage Vref, and enabling the transistor to be disconnected so as to achieve transistor short-circuit protection.

Description

technical field [0001] The invention belongs to the field of electronic circuits, in particular to a short-circuit protection method for transistors in a control circuit that uses transistors in parallel to drive a motor. Background technique [0002] In the framework of high-power low-voltage motor controllers, the power control circuit is generally realized by connecting multiple MOSFETs in parallel. When the controller is abnormal, the positive and negative electrodes of the power supply capacitor are short-circuited through the MOSFET, and the internal resistance of the MOSFET is very small, generally a few milliseconds. In Europe, the loop impedance is the sum of the PCB circuit board traces and the internal resistance of the MOSFET. At this time, the peak current of the loop will be very high, exceeding the maximum allowable operating current of the MOSFET in an instant, that is, the rate of change of the di / dt current to time will suddenly increase. At this time, if ...

Claims

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Application Information

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IPC IPC(8): H02H7/20
Inventor 封雷
Owner CHANGZHOU GLOBE
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