Charge pump circuit used for charge pump phase-locked loop

摘要

A charge pump circuit used for a charge pump phase-locked loop that includes a charging and discharging unit, two complementary circuit units, two operational amplifier units, an inverter unit, and a current mirror unit. The charge pump circuit resolves the matching problem of charging and discharging currents and the charge sharing problem in existing charge pump circuits. Both complementary circuit units positively and reversely compensate the charging and discharging unit to keep the charging and discharging currents of capacitors constant. Thus, the problem of the change of charging and discharging currents is resolved, the voltage linear variation of the charge pump capacitors is achieved, and the charging and discharging of the capacitors can be accurately controlled. The charge pump circuit is simple in structure, easy to integrate, high in the matching precision of the charging and discharging current sources, and suitable for low voltage and low power consumption applications.

主权项

1. A charge pump circuit for a charge pump phase-locked loop, comprising: a charging and discharging unit, a first complementary circuit unit, a first operational amplifier unit (A1), a phase inverter unit, a second complementary circuit unit, a current mirror unit and a second operational amplifier unit (A2), wherein
an output terminal of the charging and discharging unit is connected to a negative input terminal of the first operational amplifier unit (A1); an output terminal of the first complementary circuit unit is connected to a positive input terminal of the first operational amplifier unit (A1), and an output terminal of the first operational amplifier unit (A1) is connected to a first input terminal of the charging and discharging unit and a first input terminal of the first complementary circuit unit; an input terminal of the phase inverter unit is connected to an output terminal of the first complementary circuit unit, and an output terminal of the phase inverter unit is connected to a negative input terminal of the second operational amplifier unit (A2); an output terminal of the second complementary circuit unit is connected to a positive input terminal of the second operational amplifier unit (A2), and an output terminal of the second operational amplifier unit is connected to an input terminal of the current mirror unit and an input terminal of the second complementary circuit unit; and an output terminal of the current mirror unit is connected to a second input terminal of the charging and discharging unit and a second input terminal of the first complementary circuit unit.