Patent ID: 7868688

Claim:
A current filter circuit, the current filter circuit comprising: a source transistor comprising a drain, a gate, and a source, wherein the source of the source transistor is coupled to a reference voltage terminal, the gate of the source transistor is coupled to the gate of a mirror transistor, and the drain of the source transistor is coupled to a reference current source; the mirror transistor comprising a drain, a gate, and a source, wherein the source of the mirror transistor is coupled to the reference voltage terminal, the gate is coupled to the gate of the source transistor, and the drain is coupled to a load; a low pass filter for filtering noise in the current filter circuit, the low pass filter coupled between the drain of the source transistor and the reference voltage terminal, the input to the low pass filter being the drain of the source transistor and output being coupled to gate terminal of the mirror transistor and the source transistor, and an impedance reduction circuit coupled to the drain of the mirror transistor, wherein the impedance reduction circuit reduces bandwidth of the current filter circuit by reducing gain of the source transistor.