Single-chip smart power camera controller with photodiode current measurement down to 3 nA

Abstract

This IC, together with an external 8 b microcontroller, implements all signal conditioning, measuring and power actuation functions required by a photographic camera. All IC functions are programmed by an external microcontroller through a 16 b SPI interface. The internal low-drop regulator (0.1 V drop, 30 mA) supplies both the internal circuitry and the external microcontroller. A bandgap voltage reference is used for low sensitivity to temperature variation. To preserve battery life, the micro can shut down itself and the system by writing a bit that switches off the regulator and brings system current consumption under 500 nA.