A Bandgap Reference Startup Circuit With Very Low Leakage Current

Abstract

The invention discloses a band-gap reference starting circuit with super-low leakage current, which comprises a PMOS (P-channel Metal Oxide Semiconductor) pipe at high length-width ratio, a current mirror and an NMOS (N-channel Metal Oxide Semiconductor) switch, wherein the PMOS pipe at the high length-width ratio is used as a resistor, the NMOS switch is connected with an input end of a band-gap reference core circuit, and the current mirror is connected with an output end of the band-gap reference core circuit. According to the band-gap reference starting circuit, the NMOS switch is adopted, so that the starting speed is higher than that of the PMOS switch; after the band-gap reference core circuit normally operates, the NMOS switch is turned off, the gate source voltage of the NMOS switch is the negative voltage, so that the turn-off effect is more obvious, leakage current at any process corner and any temperature can be lower than the Pian grade, the affection of the leakage current on reference source current can be omitted, other branches of the starting circuit are still in a conducting state, however, the static current of the starting circuit is very small; in addition, the PMOS pipe resistor replaces a conventional passive resistor, and therefore, the area of a chip is saved.

Description

technical field [0001] The invention relates to a bandgap reference starting circuit with extremely low leakage current, which belongs to the integrated circuit technology. Background technique [0002] In analog circuits and mixed-signal circuits, the bandgap reference circuit is one of the very important units. Its basic function is to provide a reference voltage that is almost independent of the chip input voltage and temperature for use by other functional modules. With the development of integrated circuits and the complexity of SOC systems, the requirements for power consumption, offset voltage and startup speed of bandgap references are getting higher and higher. A very important issue in the power-independent bias circuit in the bandgap reference circuit is the existence of "degenerate" bias points, that is, there are two balanced operating points in the bandgap reference circuit, one of which is zero, and can be infinitely One remains off, and the other is the norm...

AI Technical Summary

Problems solved by technology

[0003] In most start-up circuits, as attached figure 1 , the PMOS device is mostly used as the switch to start, and the resistance is used as the current mirror of the load. The drain voltage of the PMOS is the base-emitter voltage of the triode, and the source voltage is the power supply. ) The leakage current I3 is large, and this leakage current will divert part of the triode current, so that the currents I1 and I2 of the two triodes cannot be completely matched. When the power consumption of the bandgap reference itself is very low, for example, I1 and I2 themselves are only tens of microamperes , and when the current of I3 reaches tens of nanoamperes, the current mismatch will cause the output reference voltage to be out of adjustment, and if the resistance is used as the load, the formation of the layout will increase the layout area

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