Charge pump circuit reducing noise and charge error and pll circuit using the same

Abstract

Operation noise and charge error of a charge pump circuit are reduced, thereby the jitter characteristics and the spectrum characteristics of a PLL circuit are improved, and further a time period elapsed until the PLL circuit is locked is shortened. The charge pump circuitreceives a control signal depending on an output of a phase comparison circuitfrom a control circuit, and comprises a first P-channel MOS transistor P, a second P-channel MOS transistor Pand a third P-channel MOS transistor P, and a first N-channel MOS transistor N, a second N-channel MOS transistor Nand a third N-channel MOS transistor N, and a first current source, a second current source, a third current sourceand a fourth current source. The transistor Pis turned on and off by an up-signal of the phase comparison circuit, and the transistor Nis turned on and off by a down-signal of it, and each of the transistor P, the transistor P, the transistor Nand the transistor Nis turned on and off on the basis of the control signal of the control circuit, an output signal from a VCO control terminalis input to a VCOthrough a low pass filterwhile causing current to flow through the charge pump circuit