bq2150

The bq2150 Power Gauge Module provides a complete and compact solution for capacity monitoring of Li-Ion battery packs. Designed for battery pack integration, the bq2150 incorporates a bq2050 Gas Gauge IC, a current sense resistor, and all other components necessary to accurately monitoranddisplaythecapacityof2to4seriescells.


The bq2150L includes five LEDs to display remaining capacity in 20% increments of the learned capacity. The LEDsareactivatedwiththeonboardpush-buttonswitch.


Contacts are provided on the bq2150 for direct connection to the battery stack (BAT+, BAT-) and the serial communications port (DQ). The RBI input provides backup power to the bq2050 in the event that the cells are removed or the battery is turned off. The bq2150 hasa1F capacitor onboard connected to RBI to supply backup power for about an hour. In battery packs that use high-side FETs to control the charge/discharge of the Li-Ion cells, the RBI input can be wired to a single cell to provide prolonged data retention times. The SD input allows an external signal (active low) to turn the bq2050 IC off to minimize internal current consumption of the battery pack and maximize storage life of the pack in the system. When turned off, the bq2050 is non-functional, and the RBI power source maintains register information. Please refer to the bq2050 data sheet for thespecificsontheoperationofthegasgauge.


Unitrode configures the bq2150 based on the information requested in Table 1. The configuration defines the number of series cells, the nominal battery pack capacity, and the Li-Ion battery type (coke or graphite anode).Figure1showshowthemoduleconnectstothecells.


A module development kit is also available for the bq2150. The bq2150B-KT or the bq2150LB-KT includes oneconfiguredmoduleandthefollowing:
1) An interface board that allows connection to the serialportofanAT-compatiblecomputer.
2) Menu-driven software to display charge/discharge activity and to allow user interface to the bq2050 fromanystandardDOSPC.
3) SourcecodefortheTSR.