Patent ID: 7219244

Claim:
An interface circuit for converting a first control signal with logic states of a first power domain to a second control signal with logic states of a second power domain, comprising: a first circuit powered from the second power domain and having a first input coupled to the first control signal, a second input, and an output generating the second control signal; a second circuit powered from the second power domain and having a first input coupled to a complement of the first control signal having logic states of the first power domain, a second input coupled to the output of the first circuit, and an output coupled to the second input of the first circuit; and a first keeper circuit having a power node coupled to the second power domain, an input coupled to the output of the first circuit, and an output coupled to the first input of the first circuit, wherein a first logic state of the second control signal is asserted in response to the first logic state of the complement of the first control signal, a second logic state of the second control signal is asserted in response to the first logic state of the first control signal, and the second logic state of the second control signal is held in response to the second logic state of the second control signal.