bq2164

Features:

Complete bq2004/bq2014 battery management solution for NiCd or NiMH pack
Accurate battery state-of-charge monitoring
Reliable fast charge termination
Automatic full capacity calibration
Battery information available over a single-wire bi-directional serial port
Nominal capacity,cell chemistry,and harge control parameters pre-configured
Compact size for battery pack integration


Specifications

Symbol	Parameter	Minimum	Maximum	Unit	Notes
PSR	Continuoussenseresis- torpowerdissipation	-	3	W	Thru-hole sense resistor
		-	1	W	Surface-mount sense resistor
VCHG	Charging voltage	-	20	V
TOPR	Operatingtemperature	0	+70	°C	Commercial
TSTR	Storage temperature	-40	+85	°C

Description

The bq2164 Gas Gauge Module provides a complete and compact battery management solution for NiCd and NiMH battery packs. Designed for battery pack integration, the bq2164 combines the bq2014 Gas Gauge IC with the bq2004 Fast-Charge IC on a small printed circuit board.The board includes all the necessary components to accurately monitor the capacity and reliably terminate fast chargeof5to10seriescells.


The gas gauge IC uses the onboard sense resistor to track charge and discharge activity of the battery pack. The fast chargeICgatesacurrent-limitedorconstant-currentcharging supply connected to PACK+. Charging termination is based on ?T/?tor-?V/PVD, maximum temperature, time,and voltage. The bq2004 signals charge completion to the bq2014 to indicate full capacity. The charge complete signal to the gas gauge eliminates the need to fully cycle the bat-terypacktoinitiallycalibratefullpackcapacity.


Contacts are provided on the bq2164 for direct connection to the battery stack (BAT+, BAT-), the gas gauge's communications port (DQ), and the thermistor (THERM+, THERM). The thermistor is required for temperature fast charge termination. Please refer to the bq2004 and bq2014 data sheets for the specifics on the operationofthegasgaugeandthefastchargeICs.


Unitrode configures the bq2164 based on the information requested in Table 1. The configuration defines the number of series cells, the nominal battery pack capacity, the self-discharge rate, and the fast charge control parameters. The control parameters depend on the charge rate, cell chemistry and termination techniquespecified in the configuration table. They consist of the fast charge hold-off, safety timers, and the pulse trickle rate as showninthebq2004datasheet.Thebq2164isoptimizedfor temperature termination with the thermistor provided with thedevelopmentkit. Figure 1 shows how the module connectstothecells.


The sense resistor value and type should also be specified on the configuration sheet. The two options available are a 3W through-hole type or a 1W surface-mount type. Please refer to the application note entitled "A Tutorial for GasGauging"toselectthepropervalue.


A module development kit is also available for the bq2164. The bq2164B-KT includes one configured moduleandthefollowing:
1) A serial interface board that allows connection to theRS-232portofanAT-compatiblecomputer.
2) Menu-driven software with the bq2164 to display charge/discharge activity and to allow user interfacetothebq2014fromanystandardDOSPC.
3) SourcecodefortheTSR.
4) A Philips 10K NTC Thermistor type 2322-640-63103.