Sequencing circuit for applying a highest voltage source to a chip

摘要

A sequencing circuit and sequencing method are provided for applying a highest voltage of first and second system supplies to a chip. The sequencing circuit includes a first transistor coupled between the first system power supply and a power supply input to the chip and a second transistor coupled between the second system power supply and a power supply input to the chip. The sequencing circuit includes a comparator for sensing a highest voltage of the first and second system power supplies. The first transistor and second transistor are coupled to an output of the comparator. When the comparator senses that the first power supply voltage is higher than the second power supply voltage, the first transistor is turned on and couples the first power supply voltage to the power supply input to the chip. Alternately, when the comparator senses that the second power supply voltage is higher than the first power supply voltage, the second transistor is turned on and couples the second power supply voltage to the power supply input to the chip.