Patent ID: 7830200

Claim:
A voltage bias circuit, comprising: a self-biased reference circuit disposed between an internal power supply node and a reference node and comprising bias circuits that provide at least one reference value based on a stable bias potential on at least one internal node; a bias protection circuit coupled between a device power supply node and the reference node, the bias protection circuit comprising a drive circuit that enables a controllable impedance path between the device power supply node and the internal power supply node according to a potential on at least a first supply bias voltage node, a limit circuit that enables a first current path between the first supply bias voltage node and the reference node when the first supply bias voltage node exceeds a first predetermined limit with respect to the potential at the reference node, and a feedback bias circuit that includes a first bias feedback current path coupled between the device power supply node and the reference node that is controlled according to the potential at the one internal node of the self-biased reference circuit; and a limit supply circuit that provides a current to the limit circuit according to the current provided by the first bias feedback path.