| 摘要 |
The present invention provides a circuit and method having a fast response time for generating a regulated voltage from a first voltage source. The circuit includes a driver for generating a drive signal. The driver has a clock input coupled to a clock signal. A charge pump that has a first voltage input coupled to the first voltage source. In response to the drive signal, the charge pump provides a pump voltage that is boosted from the first voltage. An amplifier has a reference input coupled to a reference voltage, a sense input coupled to a sense signal representative of the pump voltage, and an output. The amplifier is operable in response to a difference between the reference voltage and the sense signal, to control the driver. A switch is coupled from the amplifier output to an output of the charge pump such that the pump voltage is controllably boosted by the amplifier output through the switch. In another aspect of the invention the circuit is arranged in a cascode configuration to provide a low noise output voltage. The cascode configuration can provide a low noise output having an increased ripple frequency and reduced ripple amplitude. In addition, in another aspect of the invention, the cascode configuration can provide an output voltage level that is not limited by the level of the supply voltage.
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