Contribution to Safety Improvement

New Release of the NB7120 Series, the Industry-Leading High-Accuracy 1-cell Li-ion Battery Protection IC with Temperature Protection for High-Side FETs

Nisshinbo Micro Devices Inc. released the NB7120 series, the industry-leading^*1 high-accuracy 1-cell Li-ion battery protection IC with temperature protection for high-side FETs.

• *1Based on Nisshinbo Micro Devices Inc. research, as of May 8, 2024.

The market for wearable and hearable devices powered by 1-cell lithium-ion batteries is expanding due to factors such as the proliferation of virtual reality (VR) and augmented reality (AR). Safety measures for protective functions are becoming increasingly important, especially when used in equipment worn directly by humans, to prevent battery ignition and other problems.

Since the NB7120 series is a high-side N-channel MOSFET drive type that does not generate a voltage difference at ground level between the system side and the battery pack side, this product facilitates communication. By improving the accuracy of overcharge detection (-20°C to 60°C) and charge/discharge overcurrent detection to industry-leading levels for same-type products, the safety of equipment is enhanced. In addition, the new protection IC shuts down the internal circuit after over-discharge detection to minimize power consumption, and therefore can minimize the loss of battery charge during the inventory period before the product is sold.
Furthermore, the small package WLCSP-8-P15 is adopted. This product contributes to the competitiveness of customers' Li-ion battery applications with its features of high accuracy, low power consumption, improved safety and space saving.

Features

1. Industry-Leading High-Accuracy Overcharge Detection (OVP)

Cell Detection Voltage Range: 4.2 V to 4.6 V
-20°C to 60°C Temperature Range, Accuracy: ±12 mV
The improved accuracy contributes to strengthening safety in the trend of charging voltage increase even outside the room.

2. Industry-Leading High-Accuracy Overcurrent Detection in Products for High-Side FETs

• Discharge Overcurrent Detection Voltage:
  
  • 0.0080 V to 0.0300 V, Accuracy: ±1.5 mV
  • 0.0301 V to 0.0600 V, Accuracy: ±5%
  • 0.0601 V to 0.0800 V, Accuracy: ±3 mV
• Charge Overcurrent Detection Voltage:
  
  • -0.0080 V to -0.0325 V, Accuracy: ±1.5 mV
  • -0.0326 V to -0.0600 V, Accuracy: ±5%
  • -0.0601 V to -0.0800 V, Accuracy: ±3 mV

Lower voltage and more accurate overcurrent detection enables lowering sense resistor (R_SENS) resistance. Reduced board heat generation and battery pack impedance simplifies board thermal design by reducing heat generation at high currents.

3. High-Accuracy Over-Discharge Detection Voltage (UVP)

Cell Detection Voltage Range: 2.0 V to 3.4 V, Accuracy: ±35 mV
Thanks to its high accuracy, this product helps extend battery life by using the remaining battery charge close to the lower limit.

4. Industry-Leading Low Supply Current

Normal Mode: Typ. 5.0 μA
Standby Current: Max. 0.04 μA (Over-discharge detection latch type)
Low current consumption during normal operation and low standby current enable longer application run times.

5. High-Accuracy 0 V Battery Charging Inhibition Voltage

Selectable Range: 1.25 V to 2.00 V, Accuracy: ±50 mV
Since charging 0 V (low voltage) batteries can cause an internal short circuit, it can meet the requirement of setting the inhibition voltage in 0.05 V steps from a safety point of view.

6. Forced Standby Function

The CTL terminal can be used to force the product into standby mode without over-discharging the battery. Power consumption can be significantly reduced until a charger is connected.

7. Ultra-Small Package

The WLCSP-8-P15 (1.50 × 1.08 × 0.38 mm), an ultra-thin, ultra-small and leadless package, is adopted.

Main Specifications (Please refer to the datasheet for details.)

Items	NB7120 Series
Operating Input Voltage	1.5 V to 5.0 V (Absolute Maximum Rating: 6.5 V)
Supply Current	Typ. 5.0 µA (Normal mode)
Standby Current	Max. 0.04 µA
Overcharge Detection Voltage (-20°C to 60°C)	4.2 V to 4.6 V, Accuracy: ±12 mV
Over-discharge Detection Voltage	2.0 V to 3.4 V, Accuracy: ±35 mV
Discharge Overcurrent Detection Voltage	0.0080 V to 0.0300 V, Accuracy: ±1.5 mV 0.0301 V to 0.0600 V, Accuracy: ±5% 0.0601 V to 0.0800 V, Accuracy: ±3 mV
Charge Overcurrent Detection Voltage	-0.0080 V to -0.0325 V, Accuracy: ±1.5 mV -0.0326 V to -0.0600 V, Accuracy: ±5% -0.0601 V to -0.0800 V, Accuracy: ±3 mV
Short Circuit Detection Voltage	0.025 V to 0.125 V, Accuracy: ±2.5 mV
0 V Battery Charging Inhibition Voltage	1.25 V to 2.00 V, Accuracy: ±50 mV

Typical Application Circuit

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