Patent ID: 7129686

Claim:
A circuit for high PSRR, comprising: a current mirror circuit that is operable to provide a tail current based, in part, on an input current, wherein the current mirror circuit is coupled to a power supply node; a first current mirror having at least an output that is coupled to the current mirror circuit, wherein the first current mirror is an n-type current mirror; the first current mirror includes a first transistor and a second transistor; the first transistor has at least a gate, a drain, and a source; the second transistor has at least a gate, a drain, and a source; the gate of the first transistor is coupled to the gate of the second transistor, and wherein the drain of the second transistor is the output of the first current mirror; and a capacitor that is coupled between the gate of the second transistor and the power supply node such that the gate of the second transistor follows AC variations of a power supply voltage at the power supply node such that variations in the tail current due to the AC variations of the power supply voltage are approximately cancelled.