DS2792 Programmable Fuel Gauge with UART Interface

7 of 40

TYPICAL OPERATING CIRCUIT

resistor.

the voltage of each cell. Current flow through the cell pack is monitored by measuring the voltage drop across the

The GPIO pin P0.5 gates the thermistor circuit to limit current flow between measurements. The UART signals

RXD and TXD are combined into a single 3.3V bidirectional I/O line. The I/O circuit causes no extra current drain

when idle.

Figure 2. Example Pack Circuit with Regulated I/O

DS2792

2-Cell Protection

IC

VDD

VB

VIN2

VIN1

VSS, AVSS

SNS1

SNS2

TxD

RxD

DATA

PACK+

PACK-

IS1

Vx

IS2

0.1µF

0.1µF

AT103-2

1K

1K

150

10K

0.1µF

BSS84

1K

1K

1K

1K

1K

100

100

100

100

100

2N2222

2N2222

2N3906

[P0.0-P0.4]

P0.5

DETAILED DESCRIPTION

The following is an introduction to the primary features of the DS2792 programmable 2-cell Li-Ion fuel gauge. More

detailed descriptions of the device features can be found in the errata sheets and user's guides described later in

the Additional Documentation section.

DS2792 Overview

The DS2792 incorporates the 16-bit MAXQ20 microcontroller core with 16 accumulators and 16-level hardware

stack. Four memory blocks provide application code space, utility code space, RAM memory, and EEPROM

memory. Specialized peripherals are integrated to perform battery monitoring, coulomb counting, and UART

communication functions. The MAXQ20 core along with the specialized peripherals provide a flexible solution for

fuel gauging of Li-Ion or NiMH battery packs. Flexibility is further enhanced as the solution allows for upgrading of