Patent ID: 6621269
Filing Date: 2003-09-16
Classification: F02D,G01R,Y02T

Abstract:
A system for monitoring a flyback voltage of a solenoid comprising:a wave shaping circuit for transforming the flyback voltage to a logic level signal, the logic level signal having a leading edge and a trailing edge; a leading edge detection circuit for detecting a leading edge of the logic level signal, the leading edge detection circuit defining a leading edge timing window, and the leading edge detection circuit having a comparison circuit for determining whether the leading edge of the logic level signal falls within the leading edge timing window, the comparison circuit providing a plurality of signals to a state machine, wherein the state machine sets a flag variable if the leading edge of the logic level signal falls outside the leading edge timing window; a trailing edge detection circuit for detecting a trailing edge of the logic level signal, the trailing edge detection circuit defining a trailing edge timing window, and the trailing edge detection circuit having a comparison circuit for determining whether the trailing edge of the logic level signal falls within said trailing edge timing window, the comparison circuit providing a plurality of signals to a state machine, wherein the state machine sets a flag variable if the trailing edge of the logic level signal falls outside the trailing edge timing window; a register for accumulating the flags generated by the leading edge and trailing edge detection circuits; and a processor for monitoring the flags stored within the register, the processor reading the contents of the register to determine if the leading edge signal and the trailing edge signal are within their predefined windows.