BM3451 Datasheet PDF – Protection IC for Cell Battery

Part Number: BM3451

Function: 3/4/5 Cell Battery Protector

Package: SOP TSSOP 28, TSSOP 20 Pin Type

Manufacturer: BYD Microelectronics Co., Ltd


BM3451 datasheet pdf


The BM3451 is a professional protection IC for 3/4/5 cells rechargeable battery pack; it is highly
integrated, and generally used in power tools, electric bicycles and UPS applications.

The device works constantly to monitor each cell’s voltage, the current of charge or discharge, and
the temperature of the environment to provide overcharge, over-discharge, discharge overcurrent, short circuit, charge overcurrent and over-temperature protections, etc. Besides, it also can change the protection delay time of overcharge, over-discharge and discharge overcurrent by setting the external capacitors.


BM3451 pinout



(1) High-accuracy voltage detection for each cell

1. overcharge threshold 3.6V~4.6V accuracy: ±25 mV (+25 ) ℃
accuracy: ±40 mV (-40℃ to +85℃)
2. overcharge hysteresis 0.1V accuracy: ±50 mV
3. over-discharge threshold 1.6V~3.0V accuracy: ±80 mV
4. over-discharge hysteresis 0V / 0.2V / 0.4V accuracy: ±100 mV

(2) Three grades voltage detection of discharge overcurrent
– Discharge overcurrent 1 0.025 V ~ 0.30 V (50 mV step)
– Discharge overcurrent 2 0.2 V / 0.3V / 0.4V / 0.6 V
– Short circuit 0.8V / 1.2 V

(3) Charge overcurrent detection
– Detection voltage -0.03V / -0.05V / -0.1V / -0.15V / -0.2 V

(4) 3/4/5 cell protection enable

(5) Setting of output delay time
·overcharge, over-discharge, discharge overcurrent 1 and discharge overcurrent 2 protection delay
time can be set by external capacitors

(6) Supports external bleeding for balance

(7) Controlling the state of charge or discharge by external signals

(8) The maximum output voltage of CO / DO: 12V

(9) Over-temperature protection

(10) Breaking wire protection

(11) Low power consumption



1. Power tool

2. Electric bicycle

3. UPS backup battery

Other data sheets are available within the file: BM-3451



BM3451 Datasheet PDF Download