This paper presents a low power high swing charge pump for phase-locked loop (PLL) applications. The charge pump achieves low power consumption by using three switch circuits to allow one operational amplifier (OPA) to be used in both charge and discharge current mirror circuits on demand, thus the power consumption is greatly reduced and both charge and discharge current mirrors can achieve high impedance with the use of the multiplexed OPA, resulting in the charge pump exhibiting a high swing output. The charge pump is designed in 40nm CMOS process and verified under 1.2 V voltage supply, simulation results demonstrate that the designed charge pump achieves a power consumption of only 159 $\mu \mathrm{W}$, while meeting high output swing requirements of 89 mV to 1.06 V when the current mismatch rate is less than 1%, the switch time is less than 10 ps and the phase noise is -116 dBc/Hz@1MHz.