Abstract: A method of operating a four quadrant motor involves (a) monitoring a motor voltage magnitude request signal which varies between zero and a maximum value and (b) monitoring a motor direction request input. In step (c), based upon the request signal and input monitored in steps (a) and (b), a voltage request reference signal is established. In a step (d) a current magnitude request signal is monitored and in a step (e) a first current request reference signal and a second current request reference signal are established based upon the signal monitored in step (d). In a step (f) a voltage across a current sense resistor of a bus connected for powering the motor is monitored and in a step (g) a sense resistor reference signal is established based upon the signal monitored in step (f). In a step (h) the first current request reference signal is compared with a feedback current signal and in a step (i) the second current request reference signal is also compared with the feedback current signal.

Abstract: A power latch circuit for a computer is improved by the expansion of an activate control circuit to include overvoltage protection circuitry. The activate control circuit is responsive to either an activate input circuit or a feedback latch circuit to activate an activating transistor which in turn activates a series transistor providing power from a DC electric power source through a voltage regulating circuit to the computer, which is programmed to turn itself off by activating a deactivate transistor to deactivate the activating and series transistors.