Apparatus and method for disabling the operation of high power devices

摘要

A drive circuit for delivering high-level power to a load, and method of stopping a high power load from operating, are disclosed. The drive circuit includes a high power circuit capable of being coupled to the load and delivering the high level power thereto, and a to power circuit that controls the high power circuit. The low power circuit includes a first circuit portion that provides at least one control signal that is at least indirectly communicated to the high power circuit and that controls the delivering of the high level power by the high power circuit, and a second circuit portions coupled to the first circuit portion. The second circuit portion is capable of disabling the first circuit portion so that the at least one control signal avoids taking on values that would result in the high power circuit delivering the high level power to the load.

主权项

1. A drive circuit for delivering high-level power to an AC motor, the drive circuit comprising:
a high power circuit including a set of semiconductor switching devices capable of being coupled to the motor and delivering the high level power thereto; a logic circuit generating signals to control the semiconductor switching devices; a low power circuit to transmit the signals from the logic circuit to the high power circuit only when the low power circuit is receiving electrical power; and a safety relay having a contact connected to a power terminal of the low power circuit to control the application of power to the low power circuit, wherein the safety relay couples the power terminal of the low power circuit to ground to disable the low power circuit, and wherein the safety relay is electrically isolated from the logic circuit; wherein the safety relay is coupled to a pull-up resistor of the low power circuit, wherein the safety relay further disables the low power circuit by at least one of coupling the pull-up resistor to ground and decoupling the pull-up resistor from a power supply; wherein the safety relay is coupled to an override port of the low power circuit, and wherein the safety relay disables the power circuit by providing a first signal to the override port of the low power circuit.