Patent ID: 6954090

Claim:
A charge pump fabricated on a substrate for use in a phase lock loop system, the charge pump comprising: a first input stage having a first input transistor that receives a first control signal, a first complementary transistor, and a first discharging transistor, where the source terminals of the first input transistor and the first complementary transistor are connected with a drain terminal of the first discharging transistor, and the first complementary transistor is operable to receive a first reference signal having a substantially constant voltage; a second input stage coupled to the first input stage, the second input stage having a second input transistor that receives a second control signal, a second complementary transistor, and a second discharging transistor, where the source terminals of the second input transistor and the second complementary transistor are connected with a drain terminal of the second discharging transistor, and the second complementary transistor operable to receive a second reference signal having a substantially constant voltage; a first output terminal for providing an output signal having reduced switching noise, the output terminal being coupled to the second complementary transistor; a first charging transistor connected between a supply voltage and the first input transistor and a second charging transistor connected between a supply voltage and the second input transistor; and a third charging transistor connected between the supply voltage and the first complementary transistor and a fourth charging transistor connected between the supply voltage and the second complementary transistor.