STMicroelectronics Battery charger

The L6924D is a fully monolithic battery charger dedicated to single-cell Li-Ion/Polymer battery packs. It is the ideal solution for space-limited applications, like handheld equipment, and digital cameras. It integrates all of the power elements (the power MOSFET, reverse blocking diode and the sense resistor) in a small VFQFPN16 (3 x 3 mm) package. When an external voltage-regulated wall adapter is used, the L6924D works in linear mode, and charges the battery in a constant current/constant voltage (CC/CV) profile. Moreover, when a current-limited adapter is used, the device can operate in quasi-pulse mode, dramatically reducing the power dissipation. Regardless of the charging approach, a closed-loop thermal control avoids device overheating. The device has an operating input voltage ranging from 2.5 V to 12 V. The L6924D allows the user to program many parameters, such as pre-charge current, fast-charge current, pre-charge voltage threshold, end-of-charge current threshold, and charge timer. The L6924D offers two open collector outputs for diagnostic purposes, which can be used to either drive two external LEDs or communicate with a host microcontroller. Finally, the L6924D also provides very flexible control of the charge process termination and gas gauge capability, as well as other functions, such as checking for battery presence, and monitoring and protecting the battery from unsafe thermal conditions.

Key features

• Fully integrated solution, with a power MOSFET, reverse blocking diode, sense resistor, and thermal protection
• Ideal for coke and graphite anode single-cell LI-ION packs
• Both linear and quasi-pulse operation
• Closed loop thermal control
• USB BUS-compatible
• Programmable charge current up to 1 A
• Programmable pre-charge current
• Programmable end-of-charge current
• Programmable pre-charge voltage threshold
• Programmable charge timer
• Programmable output voltage at 4.1 V and 4.2 V, with ± 1 % output voltage accuracy
• (NTC) or (PTC) thermistor interface for battery temperature monitoring and protection
• Flexible charge process termination
• Status outputs to drive LEDs or to interface with a host processor
• Small VFQFPN 16-lead package (3 x 3 mm)

Applications

• Handheld devices
• Digital cameras
• Standalone chargers
• USB-powered chargers

Available tools

STEVAL-ISA076V1:

Battery charger demonstration board with integrated power switch for Li-ION/Li-POLYMER based on the L6924D

The STEVAL-ISA076V1 demonstration board is based on the L6924D battery charger system with integrated power switch. The L6924D device is a fully monolithic battery charger dedicated to single-cell lithium-ion polymer (Li-Pol) battery packs, and is the ideal solution for space-limited applications such as PDAs, handheld equipment, cellular phones, and digital cameras.

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