A High Speed ​​Reference Buffer with Cross-Coupling Filter Network

Abstract

A high-speed reference voltage buffer with a cross-coupling filter network belongs to the technical field of analog integrated circuits. It includes a reference voltage generation module and a reference voltage output buffer module. The reference voltage generation module includes a level shift circuit, two feedback loops composed of an error amplifier and a source follower MOS transistor, and a diode-connected MOS transistor. The reference voltage output The buffer module includes a CRC filter network, two source-follower output stages and a diode-connected MOS tube. The external reference voltage is passed through the level shift circuit to generate the primary positive reference voltage and the primary negative reference voltage, and then passed through the After the two feedback loops, the output terminals of the two error amplifiers are input to the CRC filter network in the reference voltage output buffer module for filtering and processing, and finally the positive reference voltage and the negative reference voltage are output through two source follower output stages. The invention saves chip area and improves response speed.

Description

technical field [0001] The invention belongs to the technical field of analog integrated circuits, in particular to a reference voltage buffer circuit with a cross-coupling filter network and fast response capability. Background technique [0002] The advancement of integrated circuit technology has continuously increased the working speed of digital circuits, requiring higher speeds for analog-to-digital converters ADC. However, with the improvement of ADC speeds, the requirements for the response speed of reference voltage buffers are also getting higher and higher, especially For a high-speed time-interleaved ADC, not only the reference voltage buffer is required to have a fast response speed, but also more stringent requirements are imposed on the mutual interference of the reference voltages between channels. In view of the above reasons, the high-speed reference voltage buffer circuit with a filter network with excellent filtering effect has become a research hotspot i...

AI Technical Summary

Problems solved by technology

[0020] Aiming at the problems of large circuit area and slow response speed in the above-mentioned traditional reference voltage buffer structure, the present invention proposes a reference voltage buffer with a cross-coupling filter network. Under the premise of ensuring the filtering effect, the area of ​​the capacitor can be reduced It is close to 4 times, which solves the problem that the traditional CRC filter network consumes a large chip area for the capacitance to ground; in addition, based on changing the fixed resistor connected to the output terminal of the negative reference voltage Vrefb to a variable resistor, the negative reference voltage Vrefb and the overall The response speed reduces the power consumption of the circuit

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