Low voltage selection control circuit for dual power supply systems

摘要

The power supply selection control circuit includes: a first comparator; a second comparator; a first reference generator coupled to a first power supply node, and having a first reference output node coupled to a first input of the first comparator and to a first input of the second comparator; and a second reference generator coupled to a second power supply node, and having a second reference output node coupled to a second input of the first comparator and to a second input of the second comparator. The first comparator provides a logic low when the first power supply voltage is lower than the second power supply voltage. The second comparator provides a logic low when the second power supply voltage is lower than the first power supply voltage.