Abstract: A circuit provides a secondary output voltage from an input voltage. The circuit includes power supply circuitry for creating an unregulated DC bus voltage line and a regulator circuit connected to the DC bus voltage line for controlling a first switch in series with a transformer winding. The control circuit samples an output voltage to control the output voltage by cycling the first switch. The circuit further includes a pulse generator circuit connected to the regulator circuit for controlling start and stop cycles of the regulator circuit and a comparator circuit connected to the pulse generator circuit for monitoring the secondary output voltage and for disabling the pulse generator circuit during normal operation of the power supply circuit.

Abstract: The present invention is a battery transfer circuit connected to a load, a power supply for powering the load with at least a minimum supply voltage during normal operating conditions, and a source of battery voltage for powering the load during a power fail condition when the power supply is unable to power said load at the minimum supply voltage. The battery transfer circuit comprises a first circuit for applying at least the minimum supply voltage to the load during normal operating conditions and a second circuit for charging the battery to an optimal voltage greater than the minimum supply voltage and for down-regulating the optimal charge voltage to a predetermined voltage and for applying the predetermined voltage to the load during the power fail condition, wherein the predetermined voltage is less than the minimum supply voltage.

Abstract: A circuit for providing a secondary output voltage from an input voltage. The circuit comprises power supply circuitry for creating an unregulated DC bus voltage line, a regulator circuit connected to the DC bus voltage line for controlling a first switch in series with a transformer winding, the control circuit sampling an output voltage to control the output voltage by cycling the switch, a pulse generator circuit connected to the regulator circuit for controlling start and stop cycles of the regulator circuit, and a comparator circuit connected to the pulse generator circuit, for monitoring the secondary output voltage and disabling the pulse generator circuit during normal operation of the power supply circuit.

Abstract: The present invention is a battery transfer circuit connected to a load, a power supply for powering the load with at least a minimum supply voltage during normal operating conditions, and a source of battery voltage for powering the load during a power fail condition when the power supply is unable to power said load at the minimum supply voltage. The battery transfer circuit comprises a first circuit for applying at least the minimum supply voltage to the load during normal operating conditions and a second circuit for charging the battery to an optimal voltage greater than the minimum supply voltage and for down-regulating the optimal charge voltage to a predetermined voltage and for applying the predetermined voltage to the load during the power fail condition, wherein the predetermined voltage is less than the minimum supply voltage.