A Sub-1V CMOS Switched Capacitor Voltage Reference with high output current capability

This paper presents an original low-voltage CMOS, bipolar transistor free, sub-threshold voltage reference capable of operating with sub-1V supply voltages. Novel aspects of the proposed solution are (i) use of a bandgap core with a single MOSFET to avoid threshold voltage error terms and (ii) adoption of an high-gain, low offset inverter-like amplifier in the bandgap feedback loop. Relatively high output current sourcing capabilities are obtained by means of an output source follower stage based on native MOSFETs. The circuit potentiality is demonstrated by means of electrical simulations performed on a prototype designed with a standard 0.18um CMOS process. A reference voltage of 0.483 V, with a maximum variation of 4mV in a temperature range of -20/80°C, has been obtained with a supply voltage of 0.7 V. The maximum output current is 200μA with a quiescient current consumpion of only 9.8μA.

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