Patent ID: 6072355
Filing Date: 2000-06-06
Classification: G11C,H03K

Abstract:
A circuit for accurately acquiring values of a high frequency analog input signal for use by a utilization circuit, comprising in combination:(a) a sampling MOSFET coupled between a first conductor conducting the high frequency analog input signal and a second conductor;(b) the utilization circuit having an input conductor coupled to the second conductor for performing a predetermined signal processing operation on successive values of the analog input signal coupled by the sampling MOSFET to the second conductor;(c) a bootstrap circuit includingi. a first bootstrap capacitor coupled between third and fourth conductors,ii. a first MOSFET coupled between a first reference voltage and the third conductor, and a second MOSFET coupled between a second reference voltage and the fourth conductor, the first and second MOSFETs being turned on in response to pulses of a first clock signal, andiii. a third MOSFET coupled between the third conductor and a gate of the sampling MOSFET, and a fourth MOSFET coupled between the fourth conductor and the first conductor, the third and fourth MOSFETs being turned on by pulses of a second clock signal which are non-overlapping with the pulses of the first clock signal, to apply a constant gate-to-source voltage to the sampling MOSFET, the gate-to-source voltage having a magnitude equal to the difference between the first reference voltage and the second reference voltage during the pulses of the second clock signal.