| 摘要 |
PURPOSE: A differential charge pump and method and a phase locked loop and method by using the same are provided to reduce the switching noise generated during the shift of the up and down signals, thereby improving the operational performance. CONSTITUTION: A differential charge pump includes a first driver(D1), a second driver(D2), a third driver(D3), a fourth driver(D4), a first transistor(P1), a second transistor(P2), a third transistor(N1) and a fourth transistor(N2). The first driver(D1) a first output signal by inputting a first input signal. The second driver(D2) generates a second output signal by inputting a second input signal. The third driver(D3) generates a third output signal having a voltage level equal to that of the first output signal by inputting the inverted signal of the second input signal. The fourth driver(D4) generates a fourth output signal having a voltage level equal to that of the second output signal by inputting the inverted signal of the first input signal. The first transistor(P1) is provided with a gate connected to a first bias voltage, a source applied thereto the first output signal and a drain connected to the first differential charge pump output signal. The second transistor(P2) is provided with a gate connected to a first bias voltage, a source applied thereto the second output signal and a drain connected to the second differential charge pump output signal. The third transistor(N1) is provided with a gate connected to a second bias voltage, a source applied thereto the third output signal and a drain connected to the first differential charge pump output signal. And, the fourth transistor(N2) is provided with a gate connected to a second bias voltage, a source applied thereto a fourth output signal and a drain connected to the second differential charge pump output signal.
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