bq26200

SLUS509A − DECEMBER 2001 − REVISED NOVEMBER 2004

7

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APPLICATION INFORMATION

1

2

3

4

8

7

6

5

REG

VCC

VSS

HDQ

STAT

SRP

SRN

OSC

bq26200PW

C3

0.1

µ F

VCC

R6

100

Ω

R5

100

Ω

BAT+

DATA

D2

5.6 V

R4

100 k

Ω

C2

0.1

µ F

R3

100 k

Ω

R1

0.02

Ω

R2

100 k

Ω

STAT

BAT−

PACK−

C1

0.1 µF

UDG−01131

Figure 3. Typical Single-Cell Li-Ion/Li-Pol Application Diagram

functional description

The bq26200 measures the voltage drop across a low-value series-current sense-resistor between the SRP

and SRN pins using a voltage to frequency converter. All data is placed into various internal counter and timer

registers. Using information from the bq26200, the system host can determine the battery state-of-charge,

estimate self-discharge, and calculate the average charge and discharge currents. During pack storage

periods, the use of an internal temperature sensor doubles the self-discharge count rate every 10

°C above

25

°C.The VFC offset is automatically compensated for in the charge and discharge counter registers.

Access to the registers and control of the bq26200 is accomplished via a single wire interface through a register

mapped command protocol that includes placing the device in the low-power mode, hardware-register reset,

programming flash from RAM, and transferring flash data to RAM.

The bq26200 can operate directly from a single Li-Ion cell or three or four nickel-chemistry cells for as long as

using a low-cost external FET in conjunction with the REG pin.

REG output

is between 2.8 V and 5.5 V. To facilitate the power supply requirements of the bq26200, the REG output is used

in conjunction with an external low-threshold n-JFET when regulation from a higher source potential is required.

The REG output remains active in sleep mode. For applications that do not need the REG output, operating

current can be reduced by turning off the operational amplifier with the DISREG bit in the MODE/WOE register.

For more details, refer to the MODE/WOE register section