Chopped wave band-gap reference circuit

Abstract

The invention provides a chopped wave band-gap reference circuit which comprises a starting circuit module, a clamping operational amplifier module, an offset voltage eliminating module and a band-gap reference module, wherein the starting circuit module is used for supplying a starting voltage to the band-gap reference module and is closed after the band-gap reference module is started; the clamping operational amplifier module is used for clamping voltages at two nodes of the band-gap reference module; the offset voltage eliminating module is used for eliminating an offset voltage of the clamping operational amplifier module; the band-gap reference module is used for generating the voltage which does not change following the temperature; the clamping operational amplifier module comprises a first chopped wave circuit, a second chopped wave circuit and a filtering circuit for a switch capacitor. A chopped wave technique is adopted by the chopped wave band-gap reference circuit for eliminating the offset voltage and acquiring a high-precision output voltage. The switch capacitor instead of a traditional RC technique is adopted by a filter, so that the area of the filter is reduced, the chip cost is lowered, and the integration degree is increased.

Description

technical field [0001] The invention relates to the field of large-scale analog integrated circuit design, in particular to a chopper bandgap reference circuit for high-precision and small-area bandgap reference realized by switched capacitor filtering, which is suitable for a system on chip (SOC). Background technique [0002] The reference voltage source is a very important unit module circuit in a CMOS integrated circuit, which can provide a high-precision and high-stability reference voltage, and is widely used in various analog and digital systems. With the continuous development of mobile communication and other communication technologies, the requirements for the reference voltage source module are getting higher and higher. [0003] The design of the CMOS reference voltage source is basically based on the bandgap reference source technology. A voltage reference source with an extremely low temperature coefficient is obtained by using a bandgap structure combined wit...

AI Technical Summary

Problems solved by technology

However, the low-pass filter that realizes chopping technology requires a large resistor and capacitor, which increases the area and cost of the chip.

Images