The MAX8934_ dual-input Li+/Li-Poly linear battery chargers with Smart Power SelectorK safely charge a single Li+/Li-Poly cell in accordance with JEITA recommendations. The MAX8934_ monitors the battery temperature (TBATT) while charging, and automatically adjusts the fast-charge current and charge termination voltage as the battery temperature varies. The MAX8934_ also monitors the battery temperature while the battery is discharging, and provides a warning flag (OT) to the system in the event that the battery is over temperature. Two safety profiles are supported (see Figure 6 for details). An ultra-low IQ, always-on LDO provides an additional 3.3V supply for system power. The MAX8934_ operates with either separate inputs for USB and AC adapter power*, or from a single input that accepts both. All power switches for charging and switching the load between battery and external power are included on-chip. No external MOSFETs are required. The MAX8934_ features a Smart Power Selector to make the best use of limited USB or adapter power. Input current limit and battery charge current limit are independently set. Input power not used by the system charges the battery. Charge current limit and DC current limit can be set up to 1.5A and 2A, respectively, while USB input current can be set to 100mA or 500mA for the MAX8934A/ MAX8934B/MAX8934C/MAX8934E and up to 1.5A (max) for the MAX8934D. Automatic input selection switches the system load from battery to external power. The MAX8934A provides a SYS output voltage of 5.3V, while the MAX8934B–MAX8934E provides a SYS output voltage of 4.35V. Other features include overvoltage protection (OVP), open-drain charge status and fault outputs, power-OK monitors, charge timers, and a battery thermistor monitor. Additionally, on-chip thermal limiting reduces the battery charge-rate to prevent charger overheating. The MAX8934_ is available in a 28-pin, 4mm x 4mm, TQFN package.
Li+ Charger with Smart Power Selector, No External MOSFETs Needed
Monitors Battery Temperature and Adjusts Charge Current and Termination Voltage Automatically per JEITA Recommendations
OT Flags System of a Hot Battery During Discharge
Common or Separate USB and Adapter Inputs
Automatic Adapter/USB/Battery Switchover
Load Peaks in Excess of Adapter Rating are Supported by Battery