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- Brand
- BYD
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- BM3451 Series
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- Other Electronics
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- Electronics
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- 2
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- EN
- Last added
- 2026-10-07
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BYD BM3451 Series 3/4/5 Cell Rechargeable Battery Protection IC Datasheet
The BM3451 series from BYD Microelectronics provides high‑integration protection for 3‑, 4‑ and 5‑cell rechargeable battery packs used in power tools, e‑bikes and UPS systems. It monitors cell voltage, charge/discharge current and temperature to prevent over‑charge, over‑discharge, over‑current, short‑circuit, and temperature hazards, and includes a capacity‑balancing function.
The device is offered in TSSOP20 and TSSOP28 packages, supports cascade operation for packs of six cells or more, and features external‑capacitor‑adjustable delay times. Detailed electrical characteristics, pin assignments, absolute maximum ratings, and application notes are provided in the following sections.
BYD BM3451 Series specifications
| Operating current (with temperature protection) | 25 µA typical |
|---|---|
| Operating current (without temperature protection) | 15 µA typical |
| Sleep current | 6 µA typical |
| Over‑charge detection voltage range | 3.6 V ~ 4.6 V |
| Charging over‑current detection voltage | -0.03 V / -0.05 V / -0.1 V / -0.15 V / -0.2 V |
Source: BYD BM3451 Series 3/4/5 Cell Rechargeable Battery Protection IC Datasheet
All BYD BM3451 Series documents by type
Ratings, dimensions and ordering codes, for selection and design work.
Questions answered in these manuals
What is the typical operating current of the BM3451 series?
The typical operating current is 25 µA when temperature protection is enabled, and 15 µA without temperature protection.
From: BYD BM3451 Series 3/4/5 Cell Rechargeable Battery Protection IC Datasheet
How does the BM3451 detect an over‑charge condition?
If any cell voltage exceeds the over‑charge detection threshold VDET1 for the programmed delay TOV, the chip pulls the CO control pin low to disable charging.
From: BYD BM3451 Series 3/4/5 Cell Rechargeable Battery Protection IC Datasheet
What is the maximum output voltage of the CO and DO pins?
Both the CO and DO pins can output up to 12 V.
From: BYD BM3451 Series 3/4/5 Cell Battery Protectors Datasheet
Which applications are recommended for the BM3451 series?
The IC is intended for power tools, electric bicycles and UPS backup battery packs.
From: BYD BM3451 Series 3/4/5 Cell Battery Protectors Datasheet