Nisshinbo NB7401 protects 2-4 series lithium cells from overcharge

Nisshinbo Micro Devices has launched the NB7401, a secondary protection IC for 2 to 4 lithium-ion or lithium-polymer battery cells in series, designed to prevent hazardous failures like thermal runaway. The IC independently detects abnormal overcharge conditions and triggers a fuse-blowing mechanism to permanently interrupt the charging path if primary protection fails. It supports up to 32 V, with overcharge detection voltages programmable from 3.55 to 3.85 V or 4.20 to 4.85 V, accurate to ±15 mV at 25°C. Operating at just 1.5 µA normally and 0.2 µA in shutdown, the NB7401 includes a built-in voltage regulator (1.2 to 3.3 V) and optional external PTC temperature monitoring. It comes in a compact DFN2020-9-HC package with configurable delay times and output voltages.