Patent ID: 7583107

Claim:
A sense amplifier circuit comprising: a reference current generation circuit coupled to a power supply, configured to generate a reference current that varies linearly with respect to changes in voltages of the power supply, and including a replica circuit to generate a replica current, based on the reference current, on a circuit path between a first supply node and a second supply node of the power supply, and a bias transistor in the circuit path, the bias transistor including a gate, a drain coupled to the gate, and a source coupled to the second supply node, the replica circuit further configured to generate a first copy of the replica current, wherein the reference current generation circuit is configured to generate the reference current such that a value of the replica current is equal to a value of a current flowing through the bias transistor minus a value of the reference current; and a sensing circuit coupled to the reference current generation circuit and configured to generate a second copy of the replica current to sense an amplitude of a current based at least in part on the second copy of the replica current.