HIGH-SPEED SAMPLING FRONT-END CIRCUIT

摘要

The present invention relates to a high-speed sampling front-end circuit, comprising an MDAC sampling network, a reference voltage generating circuit, a comparer array, an operational amplifier, an output short-circuit switch, a clock stabilizing circuit with an adjustable duty cycle, a state control module, and a feedback control module. The high-speed sampling front-end circuit has low power consumption, a high sampling rate, and high input bandwidth of the sampling network, and time constants of the MDAC sampling network and the comparer array are accurately matched, so that the input bandwidth of the sampling network is greatly improved. A sampling capacitor is used as a feedback capacitor and a DAC operational capacitor, so that a feedback coefficient of the operational capacitor is improved by more than twice, the requirement on operational amplifier bandwidth is reduced by 50%, and the power consumption of an operational amplifier is saved by more than 50%. With the adoption of the clock stabilizing circuit with an adjustable duty cycle, a sampling time is shortened, and a phase amplification time is prolonged, so that the sampling frequency is greatly improved. Only one input reference voltage is required, so that the design complexity of the reference voltage generating circuit is reduced. The present invention can be widely applied to an assembly line A/D converter.