Patent ID: 6157206
Filing Date: 2000-12-05
Classification: H03H

Abstract:
A circuit comprising:a first variable impedance device coupled between a first power supply node and a first node, the first variable impedance device having at least one control terminal;a second variable impedance device coupled between the first power supply node and a second node, the second variable impedance device having at least one control terminal;a resistive pathway coupled between the second node and ground; andan impedance control circuit having an input terminal and at least one output terminal, the input terminal of the impedance control circuit coupled to the second node, and the at least one output terminal coupled to the corresponding control terminals of the first and second variable impedance devices and wherein the impedance control circuit comprises a comparator having at least two input terminals; a first voltage divider coupled to a first one of the comparator input terminals; and a state machine coupled to an output terminal of the comparator.