Band-gap reference voltage circuit

Abstract

The invention discloses a band gap basic voltage circuit that uses a combined circuit of TG switch and capacitance for displacing RC filter circuit in existing band gap basic voltage circuit, and controls output voltage ripples by controlling turn-on time of TG switch for realizing filtering of voltage signal, accordingly, larger R or C is not needed and can overcome problem that RC filter circuit is difficult to integration, and the combined circuit of TG switch and capacitance has simple structure. A chopper circuit has higher switch frequency, and can act on filtering, increase stability of basic voltage further.

Description

technical field [0001] The invention relates to integrated circuit technology, in particular to a bandgap reference voltage circuit based on a chopper circuit and a switch filter circuit. Background technique [0002] The existing bandgap reference voltage circuit is usually composed of a chopper circuit, a control circuit and an RC filter circuit. Such as figure 1 As shown, the chopper circuit 12 receives the voltage signal provided by the constant current source, performs chopping processing on the voltage signal, and then outputs it to the resistor-capacitor (RC) filter circuit 14 through its input terminal. [0003] In practical applications, the chopper circuit 12 usually includes a proportional to absolute temperature (PTAT) circuit, a switch circuit, and an operational amplifier (not shown in the figure). Wherein, the switch circuit receives the voltage signal output by the PTAT circuit, and the switch circuit and the operational amplifier circuit cooperate to chop ...

AI Technical Summary

Problems solved by technology

But it is more difficult to integrate larger R or C into the chip

[0007] Although in the prior art, the accuracy of the voltage signal output by the chopper circuit 12 is improved by various means, such as eliminating the offset voltage and 1 / f noise in the operational amplifier of the chopper circuit 12, it still needs to be filtered by RC The circuit 14 filters the voltage signal output by the output chopper circuit 12, so there is still a problem that it is difficult to achieve integration due to the large R or C

[0008] For example, U.S. Patent US20070152740 discloses a low-power bandgap reference voltage circuit for improving accuracy and reducing area overhead. Although this patent application can improve the accuracy of the voltage signal after chopping processing at low-voltage power supply, but for chopping The processed output voltage signal is still filtered by the RC filter circuit, so there is still the problem that the RC filter circuit is not easy to integrate in the chip

[0009] And U.S. Patent US006788131 discloses a kind of circuit that produces high precision reference voltage, and this patent utilizes the digital circuit including analog / digital (A / D) converter, D / A converter and adder, divider and some controllers It replaces the RC filter circuit, but other circuits that replace the RC filter circuit have complex structure, high cost, and high requirements on the circuit

[0010] It can be seen that it is difficult to ensure the integration of the existing various bandgap reference voltage circuits under the premise of low-cost filtering

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