GENERAL DESCRIPTION
It has a fully integrated synchronous buck regulator capable of supplying up to 450mA of cache backup supply current, and the necessary logic and power devices for handling the switchover from system power to battery power. The battery charging method of the DS2731 is constant current/constant voltage (CCCV). Output voltage can be margined from 3.8V to 4.6V using a resistordivider. Charge is terminated when the charging current falls below 5% of full charge current. Switchover to battery backup is initiated by an internal comparator and occurs automatically when a sensed-input voltage drops below 2.93V. At light loads, the 2MHz internal synchronous buck regulator operates in burst mode for maximum efficiency. All nonessential functions of the DS2731 are disabled while supplying holdup current to the cache memory, and the IC goes into very low-current dormant mode when the battery voltage drops below a user-settable threshold. The DS2731 keeps track of charge status...
Maxim Integrated
