CMOS backup power switching circuit

摘要: A load circuit is provided with a backup power supply to the essential functions of in event that its primary fails or otherwise degraded. The positive terminals both and supply, having common negative reference, are input differential voltage comparator circuit. output controls switching transistor located line between load, when inverted by an inverter circuit, second load. In operation, only more voltages also available indicate which two sources applied may be further used disable non-essential portions circuitry.