L6924D

L6924D Battery charger system with integrated power switch for Li-Ion/Li-Polymer Datasheet - production data Applications • Handheld devices • Digital cameras • Standalone chargers • USB-powered chargers VFQFPN16 Table 1. Device summary Features Order code Package Packaging L6924D013TR VFQFPN16 Tape and reel • 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) February 2022 This is information on a product in full production. DocID11908 Rev 12 1/41 www.st.com Contents L6924D Contents 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Pin description and connection diagrams . . . . . . . . . . . . . . . . . . . . . . . 5 2.1 3 4 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Electrical specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 6 Operation description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 7 8 2/41 6.1 Linear mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 6.2 Quasi-pulse mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Application information: charging process . . . . . . . . . . . . . . . . . . . . . 17 7.1 Charging process flow chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 7.2 Pre-charge current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7.3 Pre-charge voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7.4 Fast charge current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 7.5 End-of-charge current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 7.6 Recharge flow chart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 7.7 Recharge threshold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 7.8 Maximum charging time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 7.9 Termination modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Application information: monitoring and protection . . . . . . . . . . . . . . 24 8.1 NTC thermistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 8.2 Battery absence detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 8.3 Status pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 DocID11908 Rev 12 L6924D Contents 8.4 9 Shutdown . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Additional application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 9.1 Selecting the input capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 9.2 Selecting the output capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 9.3 Battery floating voltage setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 9.3.1 9.4 10 Layout guidelines and demonstration board description . . . . . . . . . . . . . 33 USB battery charger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 11.1 12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Application ideas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 10.1 11 Battery floating voltage: VFLOAT VFQFPN16 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 DocID11908 Rev 12 3/41 41 Description 1 L6924D Description 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. Figure 1. Minimum application size Figure 2. Basic application schematic 5 5 &+$5*(5  9,1 95() 7+ 92616 & & , (1' 9,1616 & %$77(5