Band-gap reference circuit and chip

Abstract

The invention provides a band-gap reference circuit and a chip, the band-gap reference circuit comprises a band-gap core circuit, a starting circuit, a bias current generating circuit and an operational amplifier bias circuit, the operational amplifier bias circuit comprises a feedback tube, an upper bias current source, a current mirror load and an operational amplifier NMOS input tube, the bias current generating circuit is connected with the upper bias current source, and the current mirror load is connected with the operational amplifier NMOS input tube. The upper bias current source is connected with the current mirror load, the current mirror load is connected with the operational amplifier NMOS input tube, the current mirror load is connected with the feedback tube, the operational amplifier NMOS input tube is connected with the band-gap core circuit, the feedback tube is connected with the starting circuit, the starting circuit is connected with the band-gap core circuit, and the feedback tube is connected with a power supply end and the band-gap core circuit. The invention further provides a chip comprising the band-gap reference circuit. The gap reference circuit keeps a proper common-mode input range in a working temperature range so as to work reliably, and has the advantages of low working voltage, low noise, high reliability and the like.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to a bandgap reference circuit and a chip. Background technique [0002] Bandgap reference circuits (BGRs) play an extremely important application in integrated circuits. refer to figure 1 , BGR increases the main reference voltage and bias current for the entire system, which is the basis for the work of most analog modules. In the system power-on sequence, BGR is often the first to work following the power-on reset circuit (POR). In addition, because the lower operating voltage helps reduce the overall power consumption of the chip, the current integrated circuits require lower and lower supply voltages to reduce power consumption, and BGR, as a circuit that provides the main reference voltage, has reliable performance and operation. Performance often takes precedence in system design considerations. [0003] In order to improve the design accuracy of the traditional bandgap...

AI Technical Summary

Problems solved by technology

Because the op amp in the traditional bandgap reference circuit uses tail current bias to obtain a stable DC operating point, and the PNP voltage of the BGR clamp is usually only about 0.6V, and the higher the temperature, the smaller the voltage drop, so different PVT (process voltage temperature (that is, process, voltage, temperature) limits the input tube of the op amp, usually only PMOS tube input can be used. The PMOS tube input determines that the output common mode voltage of the first stage op amp will not be too high, and the input of the PMOS tube The first-stage load is usually a current mirror composed of NMOS transistors, and its output is fed back to the core part of the bandgap. Usually, two stages of operational amplifiers are required to form a proper DC operating point and form a good current match. In the operational amplifier gain and compensation disadvantages

[0004] Another common design see figure 2 In order to increase the input common-mode voltage of the op amp, the resistors R2 are connected in series above the PNP transistors P1 and P2 to use the NMOS transistor MN0 and MN1 input, because the common-mode input needs to ensure that the tail current and the NMOS transistor input are in a saturated state, but The disadvantage of this is that it introduces more resistor matching requirements and introduces additional offset voltage

[0005] Another disadvantage of the self-biasing approach is that it introduces another point of degeneracy to the bandgap, the point of zero current

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