LP8727

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SNVS898A – OCTOBER 2012 – REVISED MAY 2013

SINGLE INPUT LINEAR CHARGER

The LP8727 has a built-in Li-Ion/Li-Poly battery management system. Its main features are:

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Single-input linear charger

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Wide array of battery charging current options

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Flexible charging cycle control

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Thermal regulation

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Safety timer in Pre-charge mode

BATTERY CHARGER FUNCTION

A charge management system allowing safe charge and maintenance of a Li-Ion battery is implemented on the

LP8727.

Following the correct detection of a voltage at the charger input, the charger enters pre-charge mode. In this

mode the battery is charged with a small constant current. Pre-charge settings are available in register 0x08, and

charging.

In full charging mode full-rate constant current is applied to the battery, to raise the voltage to the termination

level. The charging current is programmable via CHG_SET bits. When termination voltage is reached, the

charger is in constant voltage mode, and a constant voltage is maintained. After reaching the end-of-charge

condition, the charge management isolates the battery and enters the maintenance mode.

Maintenance mode enables the battery voltage to be maintained at the correct level. If restart conditions have

been met, then the charge cycle is re-initiated to re-establish the termination voltage level.

END-OF-CHARGE AND RESTART

When EOC condition is met, the LP8727 will generate an interrupt to the processor and the processor is

Once the charger goes into maintenance mode (stop charging), the processor is also responsible for monitoring

the battery voltage and restarting the charger when the battery voltage drops to restart voltage.

PRODUCTION TEST MODE (PTM)

When PTM bit is set, then the charger enters special high-load mode. In this mode the charger should be able to

supply up to 2.3A.

OVER-VOLTAGE PROTECTION

A built-in over-voltage protection (OVP) ensures that the charger can withstand high voltages (up to 28V) on

VBUS input. When VBUS voltage exceeds the OVP threshold (typ. 6.9V), the charger operation is disabled in

order to protect the charger from breakdown. When VBUS voltage drops below the OVP threshold, the charger

automatically resumes its charging function.

THERMAL REGULATION

When the die temperature of the charger reaches the thermal regulation threshold (typ. 115°C), the thermal

regulation loop dynamically reduces the charging current to prevent the charger from being overheated. As the

die temperature drops below the thermal regulation threshold, the charging current will be automatically

increased back to the programmed charging current setting.

Copyright © 2012–2013, Texas Instruments Incorporated

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Product Folder Links: LP8727