Abstract: The current state of the art in conventional direct current (DC) power supplies is to provide direct current to a load where the direct current is derived from alternating current (AC) line voltage. There are two inherent problems with such power supplies. If a large transient occurs in the line voltage it can pass through the power supply to the DC output and damage the load. The second problem is that DC power to the load is lost if AC line voltage is lost. An Uninterruptible Power Source (UPS) is sometimes used to provide power to the load in the event of loss of AC line voltage and to provide some degree of transient protection. In many cases the UPS fails to provide the required protection. The Battery Integrated Power Supply (BIPS) circuit claimed in this application provides isolation between the load and the line to minimize damage due to transients and also provides an inherent UPS function.