Low-Power, Single/Dual-Level Battery Monitors

with Hysteresis

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13

Microprocessor power will not return until the battery has

recharged to a voltage greater than HTH+ (Figure 6).

Li+ Battery Charger Application

The MAX6430/MAX6431/MAX6432 and MAX6436/

MAX6437/MAX6438 dual-output battery monitors can

be used in conjunction with a battery charger to pro-

vide a system with additional information about the bat-

tery charge state (Figure 10). Many battery chargers,

such as the MAX1879, provide the user with a CHG

output, which tells the system that the battery is

charged. The MAX6430/MAX6431/MAX6432 and

MAX6436/MAX6437/MAX6438 dual-output battery mon-

itors provide two outputs, which can be used to relay

the battery condition to the system. This information is

useful in determining which system resources can be

powered by the battery at the current charge state.

Figure 10. Lithium-Ion Cell Charger Application (using MAX1879)

BATT

GND

1-CELL

Li+

BATTERY

THERM

ADJ

GATE

CURRENT-

LIMITED

AC WALL

ADAPTER

PULSE-WIDTH

SELECT INPUT

CHG

LED

THERMISTOR

IN

MAX1879

MAX6430

TSEL

GND

LBOL

LBOH

MAX6427

µP

BATT

LBO

NMI

Typical Operating Circuit