Seaward Elec SE9018-HF

SE9018 is a single-cell lithium battery charge management IC that accepts solar panels, standard adapters, and USB interfaces as input sources. It employs a constant current/constant voltage (CC/CV) charging mode to manage the entire charging process. The IC integrates a maximum power point tracking (MPPT) function, which automatically tracks the maximum power point of the input source to charge the lithium battery when the input power changes. Additionally, the SE9018 features constant-temperature charging: when excessive charging power causes the battery or IC temperature to rise too high, it automatically reduces the charging current to maintain a constant temperature, ensuring normal charging operation. Thanks to the internal PMOSFET architecture with integrated reverse-current protection, no external blocking diode is required. The charge termination voltage is fixed at 4.2V, and the charging current is programmable via an external resistor. The SE9018 first charges the battery rapidly in constant-current mode; when the battery voltage reaches the termination voltage, it transitions to constant-voltage mode, where the charging current gradually decreases. When the current drops to 1/10 of the programmed value, the charging process terminates automatically. When the input power source is removed, the IC automatically enters a low-power state, reducing battery leakage current to below 1uA. The SE9018 can also be placed in shutdown mode while the power supply is connected, reducing supply current to 30uA. Additional features include battery temperature monitoring, undervoltage lockout (UVLO), automatic recharge, and two LED status pins for indicating charging status and end-of-charge status.

• Programmable charge current up to 1000mA
• Maximum power point tracking
• No external MOSFET, sense resistor, or isolation diode required
• Input surge voltage protection up to 10V
• Complete linear charger for single-cell Li-ion batteries
• Constant current/constant voltage operation with integrated thermal regulation to maximize charge rate without risk of overheating
• Preset charge termination voltage of 4.2V/4.35V with ±1% accuracy
• Charge current monitor output for battery fuel gauging
• Automatic recharge support
• Dual charge status outputs indicating no-battery and fault conditions
• C/10 charge termination support
• 70uA supply current in standby mode
• 2.9V trickle charge support
• Soft-start to limit inrush current
• Battery temperature monitoring
• Available in PSOP8, SOT23-6, DFN2×2-6 packages

• Backup power / portable power banks
• Mobile phones, PDAs, GPS devices
• MP3, MP4 players
• Digital cameras, electronic dictionaries
• Portable devices, various chargers