Charge pump with switching gate bias

摘要

An apparatus including: a current source configured to generate current; a bias node coupled to the current source; a switching current source circuit coupled to the current source and the bias node to allow the current to flow through the switching current source circuit into the bias node; a biasing circuit configured to receive a control signal from a phase detector, and mirror the current flowing through the switching current source circuit in response to the control signal; and a switch device disposed between the switching current source circuit and the biasing circuit to isolate the switching current source circuit from the biasing circuit.

主权项

1. An apparatus comprising:
a current source configured to generate current; a bias node coupled to the current source; a switching current source circuit coupled to the current source and the bias node to allow the current to flow through the switching current source circuit into the bias node; a biasing circuit configured to receive a control signal from a phase detector, and mirror the current flowing through the switching current source circuit in response to the control signal, wherein the biasing circuit comprises a second transistor having gate, source, and drain terminals, a third transistor having gate, source, and drain terminals, and a second capacitor, wherein the gate terminal of the third transistor receives the control signal, the drain terminal of the third transistor is coupled to the source terminal of the second transistor, and the source terminal of the third transistor is coupled to a ground voltage; a switch device disposed between the switching current source circuit and the biasing circuit to isolate the switching current source circuit from the biasing circuit, wherein the gate terminal of the second transistor is coupled to the switch device; and an output node coupled to the drain terminal of the second transistor.