A novel current steering charge pump with low current mismatch and variation

A charge pump circuit to minimize current mismatch and current variation over a wide voltage compliance range is proposed. A feedback loop is used to cancel both deterministic and random mismatches between charging and discharging current to minimize PLL reference spurs and static phase offset. A current compensation circuit is used to minimize current variation to avoid bandwidth variation and loop instability. The circuit can operate at low supply voltage. The power overhead due to added circuitry is 3.36% making it suitable for low-power and low-voltage applications. The proposed current-steering charge pump circuit achieves mismatch lower than 0.44% over the output voltage range from 0.06 V to 0.85 V. Also the current variation is reduced to less than 1.19% when the output voltage varies from 0.06 V to 0.85 V in the 65 nm CMOS process with 1 V supply.