Overview
The L6924U, produced by STMicroelectronics, is a fully monolithic battery charger designed to safely charge single-cell Li-Ion/Polymer batteries from either a USB power source or an AC adapter. This device is ideal for space-limited portable products, integrating the power MOSFET, reverse blocking diode, sense resistor, and thermal protection into a compact VFQFPN16 package. It supports both low-power and high-power modes in USB operation and can also charge from an AC wall adapter. The L6924U operates in linear or quasi-pulse mode, depending on the power source, and features closed-loop thermal control to prevent overheating. It allows users to program various parameters such as fast-charge current, end-of-charge current threshold, and charge timer, making it highly versatile for different applications.
Key Specifications
| Parameter | Min. | Typ. | Max. | Unit |
|---|---|---|---|---|
| Operating Input Voltage (VIN) | 2.5 | - | 12 | V |
| Start-up Threshold | 4.1 | - | - | V |
| Supply Current (Charging Mode) | 1.8 | 2.5 | - | mA |
| Supply Current (Shutdown Mode) | 60 | 90 | - | µA |
| Battery Regulated Voltage (VOUT) | 4.16 | 4.2 | 4.24 | V |
| Charge Current with AC Adapter Input | 450 | 490 | 525 | mA |
| Power MOSFET Resistance (RDS(on)) | 280 | 380 | - | mΩ |
| Operating Temperature | -40 | - | 125 | °C |
Key Features
- Fully integrated solution with power MOSFET, reverse blocking diode, sense resistor, and thermal protection.
- Charges single-cell Li-Ion batteries from selectable AC adapter or USB input.
- Programmable charge current up to 1 A in AC adapter mode and up to 500 mA in USB mode.
- 4.2 V output voltage with ± 1% accuracy.
- Linear or quasi-pulse operating mode.
- Closed-loop thermal control.
- Programmable end-of-charge current and charge timer.
- (NTC) or (PTC) thermistor interface for battery temperature monitoring and protection.
- Status outputs to drive LEDs or to interface with a host processor.
- Small VFQFPN 16-lead package (3 x 3 mm).
- Gas gauge function, battery presence check, and protection from unsafe thermal conditions.
Applications
- GPS and MP3 players.
- USB-powered devices.
- Digital still cameras.
- Standalone chargers.
- Wireless appliances.
Q & A
- What is the L6924U used for?
The L6924U is used to safely charge single-cell Li-Ion/Polymer batteries from either a USB power source or an AC adapter.
- What are the operating input voltage ranges for the L6924U?
The operating input voltage ranges from 2.5 V to 12 V, with a start-up threshold of 4.1 V.
- Can the L6924U operate in different modes?
Yes, the L6924U can operate in both linear and quasi-pulse modes, depending on the power source.
- How does the L6924U manage thermal control?
The L6924U features closed-loop thermal control to prevent overheating.
- What is the maximum charge current in AC adapter mode?
The maximum charge current in AC adapter mode is up to 1 A.
- How is the battery temperature monitored and protected?
The battery temperature is monitored and protected using an (NTC) or (PTC) thermistor interface.
- What are the status outputs used for?
The status outputs can be used to drive LEDs or to interface with a host processor.
- What package type and size does the L6924U come in?
The L6924U comes in a small VFQFPN 16-lead package (3 x 3 mm).
- Does the L6924U have a gas gauge function?
Yes, the L6924U includes a gas gauge function and checks for battery presence.
- What are some common applications of the L6924U?
Common applications include GPS and MP3 players, USB-powered devices, digital still cameras, standalone chargers, and wireless appliances.
