Patent ID: 6847251
Filing Date: 2005-01-25
Classification: H03K

Abstract:
1. A differential charge pump circuit for eliminating influence of mismatches between current sources, the differential charge pump circuit comprising: a capacitor for providing an output voltage and having a first terminal and a second terminal; a first current source being connected to the first terminal of said capacitor when a comparison signal is a first level, and being connected to the second terminal of said capacitor when the comparison signal is a second level; a second current source being connected to the second terminal of said capacitor when the comparison signal is the first level, and being connected to the first terminal of said capacitor when the comparison signal is the second level; a first-common-mode current source being connected to the first terminal of said capacitor when the comparison signal is the first level, and the positive terminal being connected to the second terminal of said capacitor when the comparison signal is the second level; a second-common-mode current source being connected to the second terminal of said capacitor when the comparison signal is the first level, and the positive terminal being connected to the first terminal of said capacitor when the comparison signal is the second level; and a third-common-mode current source connected in parallel with the first current source.