Switched capacitor amplifier

Abstract

A switched capacitor amplifier comprises a switched capacitor module, an amplifier module and a sample hold output module, the switched capacitor module uses a first control clock, a second control clock and a third control clock which have different phases to control opening and closing of corresponding switches, and adds a first input voltage and a second input voltage in proportion, and the switched capacitor amplifier is particularly suitable for adding the voltage with a positive temperature coefficient and the voltage with a negative temperature coefficient in a reference voltage sourceaccording to the temperature coefficient proportion to obtain the reference voltage with the zero temperature coefficient. The amplifier module only uses two MOS transistors, the structure is simple,and in combination with the effect of the switched capacitor module, under the condition that the open-loop gain of the amplifier is small, a small gain error can still be obtained. In addition, underthe condition of the same output voltage precision, the power supply voltage and the reference voltage can be effectively reduced, and the design of a low-voltage low-power-consumption circuit is facilitated.

Description

technical field [0001] The invention belongs to the field of switched capacitors and amplifiers, and relates to a switched capacitor amplifier, which is especially suitable for a reference voltage source and is used for proportionally adding positive temperature coefficient voltages and negative temperature coefficient voltages generated by the reference voltage source. Background technique [0002] The working principle of the reference voltage source is: generate a voltage VPTAT with a positive temperature coefficient and a voltage VCTAT with a negative temperature coefficient and add them in a certain ratio, thereby generating a reference voltage with a temperature coefficient close to zero. Traditional reference voltage sources generally superimpose VPTAT on VCTAT in a certain proportion. The disadvantage of this is that the reference voltage cannot be made very low, and the power supply voltage of the reference source cannot be reduced. Under the trend of integrated cir...

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Problems solved by technology

[0004] Aiming at the problems that the reference source power supply voltage cannot be made very low and the overall power consumption of the circuit is increased in the above-mentioned traditional switched capacitor amplifier, the present invention proposes a switched capacitor amplifier, which can reduce the gain error by using a small open-loop gain A It is very small and can be used in the scene of adding voltages, especially in the reference voltage source, which is used to add the positive temperature coefficient voltage and the negative temperature coefficient voltage generated by the reference voltage source in proportion to obtain a zero temperature coefficient reference voltage, and the supply voltage of the reference source can be made very low

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