| 摘要 |
An apparatus for detecting short circuit condition in a MOSFET power transistor in a pulse width modulation controller for a commutator type direct current motor detects whether current is flowing through the channel of the transistor by monitoring current through a normally closed override means. The apparatus further monitors the control signal to the transistor gate, determining when the control signal should have cut off current through the transistor channel. An error condition is indicated when the invention detects current through the channel at a time when the control signal to the transistor gate should have cut off current through the channel. Responsive to detection of an error condition, embodiments open the override means, thereby cutting off current supplied to the motor. Embodiments further provide an alarm signal to indicate MOSFET failure.
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