The Intersil ICL7673 is a monolithic CMOS battery backup circuit that offers unique performance advantages over conventional means of switching to a backup supply. The ICL7673 is intended as a low-cost solution for the switching of systems between two power supplies; main and battery backup. The main application is keep-alive-battery power switching for use in volatile CMOS RAM memory systems and real time clocks. In many applications this circuit will represent a low insertion voltage loss between the supplies and load. This circuit features low current consumption, wide operating voltage range, and exceptionally low leakage between inputs. Logic outputs are provided that can be used to indicate which supply is connected and can also be used to increase the power switching capability of the circuit by driving external PNP transistors.

The Intersil ICM7228 display driver interfaces microprocessors to an 8-digit, 7-segment, numeric LED display. Included on chip are two types of 7-segment decoder, multiplex scan circuitry, LED display segment drivers, LED display digit drivers and an 8-byte static memory as display RAM. Data can be written to the ICM7228A and ICM7228B?s display RAM in sequential 8-digit update or in single-digit update format. Data is written to the ICM7228C display RAM in parallel random access format. The ICM7228A and ICM7228C drive common anode displays. The ICM7228B drives common cathode displays. All versions can display the RAM data as either Hexadecimal or Code B format. The ICM7228A and ICM7228B incorporate a No Decode mode allowing each bit of each digit's RAM word to drive individual display segments resulting in independent control of all display segments. As a result, bargraph and other irregular display segments and formats can be driven directly by this chip.