High Speed ​​High Precision Drivers for Switched Capacitor Circuits

Abstract

The invention relates to a high-speed and high-precision driver for a switched capacitor circuit, belonging to the technical field of analog or digital-analog hybrid integrated circuit drivers. The driver includes a high-gain operational amplifier unit and a high-precision rapid establishment control module; the high-gain operational amplifier unit specifically includes: a differential operational amplifier AMP providing high gain, a PMOS transistor P0 providing output current, and a tail current providing Tail current source N0; the high-precision rapid establishment control module specifically includes: an ADC with a Flash structure, two impedance transformation units Z1 and Z2, and a capacitor C1. Compared with the traditional structure, the invention has higher linearity performance, can effectively meet the requirements of high-speed and high-precision drivers, and is especially suitable for the design of switched capacitor circuit drivers in analog or digital-analog hybrid integrated circuits.

Description

technical field [0001] The invention belongs to the technical field of analog or digital-analog hybrid integrated circuit drivers, and relates to a high-speed and high-precision driver for switched capacitor circuits. Background technique [0002] In recent years, with the further improvement of the performance index of the digital-to-analog / analog-to-digital converter, the performance requirements of the driver that provides the common mode or reference voltage inside the chip are also getting higher and higher. However, the circuit structure of the traditional driver is relatively simple. Under the condition of high operating frequency, it has the disadvantage of insufficient establishment accuracy, which affects the overall linearity. Especially in some applications in high-precision fields, traditional drivers cannot meet the requirements for linearity. [0003] Resistive driver circuits such as figure 1 As shown, the circuit mainly includes two voltage dividing resisto...

AI Technical Summary

Problems solved by technology

However, there are two problems with this structure. First, after the switch SW is turned on, the settling time of capacitor C2 will change with the initial voltage of the plate on C2. In the case of incomplete settling, the linearity will vary with the input voltage. Second, because there is a phase difference between the input and output of the operational amplifier, after the switch SW is turned on, the settling time of the capacitor C2 is not necessarily in the optimal interval

The above two points will seriously affect the linearity of the circuit when the circuit is working at high speed

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