Abstract: A system and method for providing an alternate AC voltage to an electrical load having a main AC voltage. The system and method include a signal generator for generating a main AC voltage signal representing the value of the main AC voltage, and a processor for processing the main AC voltage signal to determine a status of the main AC voltage, a main AC voltage failure time period, and a main AC voltage restoration time period. The system and method also include a control signal generator for generating a control signal in response to the main AC voltage signal, the main AC voltage failure time period, the main AC voltage restoration time period, and a pre-selected delay time period, and a switch for switching the electrical load between the main AC voltage and the alternate AC voltage in response to the control signal.

Abstract: A method and system of converting a wide range of DC input voltages from a DC power source to a substantially lower regulated DC output voltage is disclosed. A pulse width modulated (PWM) signal is generated from an applied DC input voltage to obtain a desired regulated DC output voltage. The PWM signal has a fixed frequency and a variable duty cycle. The PWM signal is filtered to provide a DC output voltage proportional to the amount of time the PWM signal spent in the ON or HIGH state. The duty cycle of the PWM signal is controlled based on an error signal generated by comparing an error voltage level that is proportional to the output voltage to a voltage reference. High voltage protection is provided to the controller during the period the PWM signal is in the OFF or LOW state.