Ultra low power temperature insensitive current source with line and load regulation

摘要

A temperature insensitive sub-nA current reference is presented with pA-range power overhead. The main concept is to linearly reduce the gate voltage of a sub-threshold-biased MOSFET as temperature increases, in order to compensate for exponential dependence of drain current on temperature. For example, a MOSFET-only, 20 pA, 780 ppm/° C. current reference that consumes 23 pW is disclosed, marking the lowest reported power among current references. The circuit exploits sub-threshold-biased MOSFETs and a complementary-to-absolute temperature (CTAT) gate voltage to compensate for temperature dependency. The design shows high immunity to supply voltage of 0.58%/V and a load sensitivity of 0.25%/V.

主权项

1. A current reference circuit, comprising:
a voltage regulator configured to receive a supply voltage and output a constant regulated voltage, the voltage regulator comprised of transistors operating only in the subthreshold region; an output stage having an output transistor, wherein the output transistor has a drain terminal configured to produce a reference current and is operating only in a subthreshold region; and a complementary-to-absolute temperature (CTAT) voltage generator configured to receive the regulated voltage from the voltage regulator and supply a gate voltage to a gate terminal of the output transistor, where the CTAT voltage generator is comprised of transistors operating only in the subthreshold region and the CTAT voltage generator adjusts the gate voltage linearly and inversely with changes in temperature.