Advanced Micro Devices, Inc.
Low voltage power on reset circuit

Abstract:

A power supply detection circuit for an integrated circuit (IC) includes a reference voltage circuit and a comparator circuit. The reference voltage circuit produces a reference voltage from the supply voltage at a reference voltage node. The comparator circuit includes a first p-type metal oxide semiconductor (PMOS) transistor with a source coupled to a positive supply terminal, a gate receiving the reference voltage, and a drain connected to a comparator output terminal. A first n-type metal oxide semiconductor (NMOS) transistor has a drain connected to the comparator output terminal, a source connected to the negative supply terminal, and a gate receiving a second voltage that varies relative to the supply voltage. A second PMOS transistor has a source coupled to the positive supply terminal, a gate connected to the reference voltage node, and a drain providing the second voltage and coupled to a filter.