2S Li-ion Battery Protection Board (Code 18) — Product Introduction

Overview

This protection board employs the PWCHIP PW7120 protection IC and two PW4406A MOSFETs to provide complete overcharge, over-discharge, overcurrent, and short-circuit protection for 2S lithium-ion battery packs (7.4 V nominal, 8.4 V fully charged). It supports a continuous discharge current of 3 A and an overcurrent protection threshold of approximately 7 A. The integrated PW4084 synchronous buck charger accepts DC input from 10 V to 15 V and delivers up to 2 A charge current to the battery.

Specifications

Parameter	Specification
Battery Type	2S (2-series Li-ion, 7.4 V nominal, 8.4 V fully charged)
Continuous Discharge Current	3 A
Overcurrent Protection Threshold	Approx. 7 A
Protection IC	PW7120
MOSFETs	PW4406A × 2
MOSFET Package	SOP-8
Charging Input	DC 10 V–15 V
Charging IC	PW4084
Charging Topology	Synchronous buck charging
Battery-Side Charging Current	2 A

Key ICs

PW7120 is a dedicated 2-cell lithium-ion protection IC integrating overcharge, over-discharge, overcurrent, and short-circuit protection. It requires minimal external components and offers low standby power.

PW4084 is a synchronous switching buck charger with conversion efficiency up to 93 %. It accepts 10 V–15 V input and steps it down to 8.4 V at 0.5 A–2 A. The IC integrates input OVP, disabling charging when the input exceeds 15 V, and withstands input voltages up to 25 V.

Key Features

· Single-board protection and charging solution

· PW4084 synchronous buck charging with up to 93 % efficiency

· 10 V–15 V DC input stepped down to 8.4 V, delivering 2 A charge current

· Integrated 15 V OVP shutdown and 25 V input withstand

· PW7120 protection IC plus two PW4406A MOSFETs for 7 A overcurrent protection

· Optimized for 2S battery packs powered by 12 V adapters

Schematic

Code 18 Schematic

PCB Photo

Code 18 PCB Photo

Typical Applications

In-vehicle devices, 12 V solar power systems, security equipment, LED lighting, industrial instruments.

Wiring Notes

Connect the battery as indicated on the schematic. The charge/discharge terminals are P+ and P-.

Documentation & Technical Support

We provide chip samples, technical documentation, and circuit design support. For more information or to request materials, please contact us at support@pwchip.com or reach an authorized distributor at https://www.pwchip.com/page/180.html.