A kind of operational amplifier dynamic power supply circuit and power supply method

Abstract

The invention discloses a dynamic power supply circuit for an operational amplifier and a power supply method. The circuit comprises a signal input unit, a gain adjusting unit and a power supply, wherein the signal input unit is connected with the gain adjusting unit; an input signal superposition unit, a supply voltage control unit and a power driving unit which are connected with one another are arranged between the signal input unit and the gain adjusting unit; and the power supply is connected with the supply voltage control unit and the power driving unit respectively. The dynamic power supply circuit and the power supply method are mainly characterized in that a supply voltage of the gain adjusting unit varies along with an amplitude of an input signal according to a constant proportion, so that large-signal and large-bandwidth signal conditioning is realized through the operational amplifier with a low conversion rate, and the power consumption and noise of an amplification circuit can be lowered.

Description

technical field [0001] The invention relates to signal conditioning in the fields of testing and measurement, computer, communication, etc., in particular to a dynamic power supply circuit for an operational amplifier and a power supply method. technical background [0002] Signal conditioning is required in the fields of test and measurement, computer, communication, etc. The most used in conditioning circuits is the integrated operational amplifier, which is usually powered by a DC voltage source. Frequency response and transient response of the integrated op amp When a large signal is input, the op amp will work in the nonlinear region, and usually its input stage will produce instantaneous saturation or cut-off phenomenon, so the compensation capacitor is often added inside the op amp. Due to the compensation capacitance inside the integrated op amp, the inter-electrode capacitance and stray capacitance between the BJTs at all levels, etc., during the transient process o...

AI Technical Summary

Problems solved by technology

Due to the compensation capacitance inside the integrated op amp, the inter-electrode capacitance and stray capacitance between the BJTs of all levels, etc., the output voltage of the op amp will only follow the input voltage after the capacitance of the circuit is charged during the transient process of the input large signal. Do linear changes, which limits the slew rate of the op amp

Similarly, chip manufacturers need to provide a larger charging current inside the op amp in order to obtain a high slew rate op amp. As a result, the high slew rate op amp needs to have a large quiescent current and consume more power. It also limits the power supply voltage of the operational amplifier with high conversion rate cannot be too large, and the input voltage range is not high

[0003] On the other hand, the noise of the op amp is closely related to the supply current and voltage. Large current and voltage will introduce more noise, which indicates that the op amp with high conversion rate has greater noise.

Therefore, using conventional integrated op amps to achieve high-bandwidth, large-signal, high-precision signal conditioning, noise can become an issue

[0004] The AC-coupled input signal has a high input source impedance, which makes it difficult to discharge the residual voltage on the internal compensation capacitor, inter-electrode capacitance and stray capacitance of the integrated op amp. For large signals of different frequencies, the op amp currently used in the market adopts Conventional circuit conditioning, there will be a different DC voltage offset

Images