Fully differential comparator and fully differential amplifier

Abstract

A first to a fourth sampling switch (1a to 1d), a first to a fourth sampling capacitor (4 to 7), and a first and a second charge redistribution switch (2a, 2b) are provided on the input side of a differential amplifier (8). A first and a second reset switch (3a, 3b) are provided between the input and the output of the differential amplifier (8). An input signal voltage (Vinp) having a positive polarity, a comparison reference voltage (Vrefn) having a negative polarity, a comparison reference voltage (Vrefp) having a positive polarity, and an input signal voltage (Vinn) having a negative polarity are respectively applied through a first to a fourth sampling switch (1a to 1d) to one end of each of the first to the fourth sampling capacitor (4 to 7). During a reset period, the reset of the differential amplifier (8) is released after sampling of each voltage is completed, and during a comparison period, the first and the second charge redistribution switch (2a, 2b) are electrically connected.

Description

technical field [0001] The invention relates to a technology capable of realizing high-precision comparison and high-precision amplification of differential input signals under the condition of high-speed operation and low power consumption in a fully differential analog signal processing circuit with a large dynamic range. Background technique [0002] In recent years, there has been an increasing demand for lower voltage, higher speed, and lower power consumption of analog signal processing circuits. For this reason, recently, technologies using a switched capacitor structure combining an amplifier and a capacitor of a CMOS analog circuit, which can secure a dynamic range under low power supply voltage conditions and realize high-speed operation, are becoming mainstream. [0003] On the other hand, from the viewpoint of the interface technology between analog and digital, general-purpose ADC (analog-to-digital converter) resolution improvement and high-speed performance ar...

AI Technical Summary

Problems solved by technology

In addition, when comparing a differential input signal that is very close to the differential comparison reference voltage, there are also problems such as charge injection at the time of switch switching for charge storage in the chopper capacitor, and feed-through shift of the switch. It is asymmetrical depending on the voltage level difference between positive and negative, so the error cannot be canceled and the comparison accuracy deteriorates

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