High-precision li-ion battery secondary protection IC
26 August 2026 
Nisshinbo Micro Devices, a leader in innovative semiconductor products, has announced the launch of the NB7401, a highly integrated secondary protection IC designed for 2 to 4 lithium-ion or lithium-polymer battery cells connected in series.
The company say engineered with a high-voltage tolerant process and precise voltage detection technology, the NB7401 is tailored to meet the stringent safety requirements of modern battery-powered applications.
The NB7401 offers an additional layer of security in multi-cell battery applications. While primary protection ICs typically manage standard charge/discharge cycles and basic threshold monitoring, secondary protection ICs are critical in scenarios where the primary circuitry fails or becomes unresponsive. The NB7401 detects abnormal overcharge conditions independently and triggers a fuse-blowing mechanism to interrupt the charging path permanently, effectively preventing hazardous scenarios such as thermal runaway or battery rupture.
The NB7401 supports the supply voltage tolerance of up to 32 V, and offers overcharge detection voltages programmable from 3.55 to 3.85 V and 4.20 to 4.85 V with high accuracy (±15 mV at 25°C). It also incorporates an optional overcharge timer reset delay, ensuring resilience against noise-induced false triggers, with delay times configurable to 2, 4, or 6 seconds. Key attributes of the NB7401 include an ultra-low operating current of just 1.5 µA during normal operation, and switches to a minimal shutdown current of 0.2 µA to conserve battery life, activated when any cell voltage falls below a configurable threshold. To support external components like real-time clocks, it integrates a built-in voltage regulator delivering a stable output between 1.2 V and 3.3 V, accurate within ±2%. Additional safety can be acquired by connecting an external PTC to monitor the temperature of the battery pack.
The NB7401 is available in multiple configurations, with selectable set voltages, delay times, and output voltages tailored to specific design needs. The product is manufactured in a compact DFN2020-9-HC package, suitable for use in small-sized applications and gadgets.
https://www.linkedin.com/company/nisshinbo-micro-devices-inc