PLL 적용을 위한 900㎒급 저전압 고속 차지펌프 설계

다국어 초록 (Multilingual Abstract)

In this paper, we propose a novel low-voltage and high-speed charge pump for PLL applications. The conventional current steering method charge pump has problems of current spark and charge sharing. In the low-voltage charge pump the switching speed of current mirror MOSFETs is limited. For those problems, the charge pump that we implemented can reduce the influences of current spark and charge sharing due to it's differential construction, hence the waveform of the output shows a stable step. Also the proposed charge pump improves the speed limit of the current mirror MOSFETs. Moreover we use the non full-swing signals to improve the switching speed of the switch MOSFETs. The maximum operating frequency of the proposed charge pump is improved to 900㎒ in 1.5V supply voltage with 15㎂ reference current. The proposed charge pump is implemented in a standard CMOS 0.18㎛ technology and simulated by HSPICE.