| 摘要 |
At least upper order stages of a multi-stage charge pump contain respective drive signal recovery circuits, that enable the charge pump to operate over a larger voltage range and/or be driven by a very small input voltage. The switch control signal recovery circuit has an auxiliary NFET switch whose current flow path is series-coupled with a Schottky diode between the output voltage of the next lower order stage and a PFET switch drive line. The auxiliary switch controllably clamps the PFET switch drive line at a voltage that differs from the output voltage of the next lower order charge pump stage by the voltage drop across the Schottky diode. This effectively guarantees that the level-shifted line of that stage's transient clamp network will be biased to its appropriate operating voltage level, so that the clamp rail of this stage cannot hang up at a voltage level that is well below the output voltage from the next lower order stage.
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