Features

➤ Accurate measurement of available

charge in rechargeable batteries

➤ Designed for electric assist bicycles

and other applications

➤ Measures a wide dynamic current

range

➤ Supports NiCd,NiMH or lead acid

➤ Designed for battery pack integration

- 120μA typical standby current

(self-discharge estimation mode)

- Small size enables implementations

in as little as 1

2 square inch of PCB

➤ Direct drive of LEDs for capacity

display

➤ Automatic charge and selfdischarge

compensation using internal

temperature sensor

➤ Simple single-wire serial communications

port for subassembly

testing

➤ 16-pin narrow SOIC

General Description

The bq2013H Gas Gauge IC is intended

for battery-pack installation to

maintain an accurate record of a battery’s

available charge. The IC monitors

a voltage drop across a sense resistor

connected in series between the

negative battery terminal and ground

to determine charge and discharge activity

of the battery. The bq2013H is

designed for high cpaacity battery

packs used in high-discharge rate systems.

Battery self-discharge is estimated

based on an internal timer and temperature

sensor. Compensations for

battery temperature, rate of charge,

and self-discharge are applied to the

charge counter to provide available

capacity information across a wide

range of operating conditions. Initial

battery capacity, self-discharge rate,

display mode, and charge compensation

are set using the PROG1-6 pins.

Actual battery capacity is automatically

“learned” in the course of a discharge

cycle from full to empty.

Nominal available charge may be

directly indicated using a five-segment

LED display. These segments

are used to graphically indicate

nominal available charge.

The bq2013H supports a simple

single-line bi-directional serial link to

an external processor (common

ground). The bq2013H outputs battery

information in response to external

commands over the serial link. To

support battery pack testing, the

outputs may also be controlled by

command. The external processor

may also overwrite some of the

bq2013H gas gauge data registers.

The bq2013H may operate directly

from four nickel cells or three lead

acid. With the REF output and an

external transistor, a simple, inexpensive

regulator can be built to provide

VCC from a greater number of cells.

Internal registers include available

charge, temperature, capacity, battery

ID, and battery status.