Functional Description

General Operation

The bq2013H determines battery capacity by monitoring

the amount of charge input to or removed from a recharge-

able battery. The bq2013H measures discharge and charge

currents, estimates self-discharge, monitors the battery for

low-battery voltage thresholds, and compensates for tem-

perature and charge rates. The charge measurement is

made by monitoring the voltage across a small-value se-

ries sense resistor between the battery’s negative terminal

and ground. The available battery charge is determined

by monitoring this voltage over time and correcting the

measurement for the environmental and operating condi-

tions.

Figure 1 shows a typical battery pack application of the

bq2013H using the LED display.

The bq2013H can be

configured to display capacity in either a relative or an

absolute display mode. The relative display mode uses

the last measured discharge capacity of the battery as

the battery “full” reference. The absolute display mode

uses the programmed full count (PFC) as the full refer-

ence, forcing each segment of the display to represent a

fixed amount of charge. A push-button display feature

is available for enabling the LED display.

The bq2013H monitors the charge and discharge cur-

ure 1). A filter between the negative battery terminal

and the SR pin is required.

3

bq2013H

FG2013H1.eps

PROG6

SEG5/PROG5

SEG4/PROG4

SEG3/PROG3

SEG2/PROG2

SEG1/PROG1

VSS

DISP

SB

VCC

REF

bq2013H

Gas Gauge IC

LCOM

RBI

HDQ

DONE

100K

Q1

ZVNL110A

R1

C1

RS

H, Z, or L

To

µC

RB1

0.1

µF

RB2

Load

Charger

To

µC or

Fast Charger

2. The battery stack voltage can be directly connect to VCC across 4 nickel cells

(4.8V nominal and should not exceed 6.5V) with a resistor and a zener diode

to limit voltage during charge. Otherwise, R1and Q1 are needed for

regulation of > 4 nickel cells.

3. Programming resistors and ESD-protection diodes are not shown.

4. R-C on SR is required.

SR

1.

Indicates optional.

Notes:

Figure 1. Application Diagram: LED Display