3S Li-ion Battery Protection Board — Code 9 Product Introduction

Overview

This protection board adopts Pingxin Micro’s self-developed PW7126 protection IC, paired with four PW4406A MOSFETs. It delivers complete overcharge, over-discharge, overcurrent, and short-circuit protection for 3S (three-cell series Li-ion) battery packs rated at 11.1 V nominal and 12.6 V fully charged. The board supports a continuous discharge current of 6 A, with an overcurrent protection threshold of approximately 7 A. An integrated PW2213 cell-balancing IC effectively extends the service life of the battery pack.

Specifications

Parameter	Specification
Battery Type	3S (three-cell series Li-ion pack, 11.1 V nominal, 12.6 V fully charged)
Continuous Discharge Current	6 A
Overcurrent Protection Current	~7 A
Protection IC	PW7126
MOSFET	PW4406A × 4
MOSFET Package	SOP8
Cell Balancing	With balancing
Balancing IC	PW2213

Main Control IC Introduction

PW7126 is a protection IC dedicated to 3-cell Li-ion batteries. It integrates overcharge, over-discharge, overcurrent, and short-circuit protection, and supports high-precision voltage detection.

PW2213 is a high-precision cell-balancing IC that effectively eliminates voltage differences among cells, extends battery pack service life, and ensures consistent charge/discharge behavior.

Solution Features

· Four PW4406A MOSFETs in parallel, 7 A overcurrent protection, 6 A continuous discharge

· PW2213 three-cell balancing function automatically equalizes the voltage of all three cells

· Balancing function extends battery pack cycle life by more than 30%

· SOP8-packaged MOSFETs offer a balanced cost-performance ratio

· Ideal for 3S battery pack applications requiring long service life

Circuit Schematic

Circuit Schematic

PCB Physical Image

Dimensions: 58 mm × 33 mm

PCB Physical Image

BOM (Bill of Materials)

No.	Designator	Model / Specification	Qty
1	C1, C2, C3	0603 0.1 µF / 25 V	3
2	CVC1	0603 1 µF / 16 V	1
3	CVC2, CVC3	0603 0.1 µF / 16 V	2
4	Q1, Q2, Q3	PW2302 SOT-23-3L	3
5	R1, R2, R3, RVC1, RVC2, RVC3	0603 1 kΩ ±1%	6
6	RBAL1, RBAL2, RBAL3	2512 620 Ω ±1%	3
7	RSENSE	2512 14 mΩ ±1%	1
8	RVIN, RVM	0603 2.21 kΩ ±1%	2
9	U1	PW7126 SOP8	1
10	U2, U3, U4, U5	PW4406A SOP8	4
11	U6, U7, U8	PW2213 SOT23-6L	3

Typical Applications

Power tools, electric scooters, massage guns, high-power LED lights, and electric garden tools.

Wiring Instructions

Please refer to the circuit schematic for battery connection. The charge/discharge interface is P+ and P-.

Documentation & Technical Support

We provide IC samples, technical documentation, and circuit design support. For more solutions or to request materials, please contact us at support@pwchip.com or reach out to our distributors at https://www.pwchip.com/page/180.html.

PW7126 + PW80N03×2 3-Cell Li-ion Battery Charge-Discharge Protection Board Solution, Continuous 7A, Overcurrent Protection 10A

Product Details PCB Design Suggestions