Features

ä Complete bq2050H Power Gauge solution for Li-Ion

battery packs

ä Battery information available over a single-wire

(HDQ) bidirectional serial port

ä Control signals to enhance pack protection

ä Battery state-of-charge monitoring for 2- to 5-cell

series applications

ä On-board regulator allows direct connection to the

battery

ä “L” version includes push-button activated LEDs to

display state-of-charge information

ä Nominal capacity pre-configured

ä Compact size for battery pack integration

General Description

The bq2150H Power Gauge Module provides a complete

and compact solution for capacity monitoring of Li-Ion bat-

tery packs. Designed for battery pack integration, the

bq2150 incorporates a bq2150H Gas Gauge IC, a current

sense resistor, and all other components necessary to accu-

rately monitor and display the capacity of 2 to 5 series

cells.

The bq2150L includes five LEDs to display remaining ca-

pacity in 20% increments of the learned capacity.

The

LEDs are activated with the onboard push-button switch.

Contacts are provided on the bq2150H for direct connec-

tion to the battery stack (BAT+, BAT-) and the serial

communications port (HDQ). The RBI input provides

backup power to the bq2150H in the event that the cells

are removed or the battery is turned off. The bq2150H

hasa1

µF 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

bq2050H IC off to minimize internal current consump-

tion of the battery pack and maximize storage life of the

pack in the system. When turned off, the bq2150H is

non-functional, and the RBI power source maintains

register information. Please refer to the bq2050H data

sheet for the specifics on the operation of the Gas Gauge.

Unitrode configures the bq2150H based on the informa-

tion requested in Table 1. The configuration defines the

number of series cells, the nominal battery pack capac-

ity, and the Li-Ion battery type (coke or graphite anode).

Figure 1 shows how the module connects to the cells.

A module development kit is also available for the

bq2150. The bq2150HB-KT or the bq2150HLB-KT in-

cludes one configured module and the following:

1)

An EV2200-50H interface board that allows con-

nection to the serial port of an AT-compatible com-

puter.

2)

Menu-driven software to display charge/discharge

activity and to allow user interface to the bq2150H

from any standard Windows 3.1x or 95 PC.

Pin Descriptions

P1

HDQ/Serial Communications port

P2

PSTAT/Protector status input

P3

BAT+/Battery positive/pack positive

P4

SD/Shutdown

P5

RBI/Register backup input

P6

GND/Ground

P7

PACK-/Pack negative

P8

BAT-/Battery negative

P9

CFC/Charge FET control output

1

Li-Ion Power Gauge™ Module

Preliminary

bq2150H

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