BQ771800 / BQ771801 / BQ771802 / BQ771803

Chang-woo YANG

Expert 1285 points

Hello~

I have one question from "FUNCTIONAL BLOCK DIAGRAM" of BQ77180x datasheet.

What is this in the red rectangle as below??

Thanks... C.W. :)

0 MaciejKucia over 12 years ago

This is a three-terminal fuse.

See:

Battery Circuit Architecture, I. TYPICAL BATTERY CIRCUITRY FOR A LI-ION BATTERY PACK by Bill Jackson: http://www.ti.com/lit/ml/slyp087/slyp087.pdf
IEEE Xplore, The Three-Terminal Fuse: A New Switching Device by Simon S. Cohen: http://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=00391220

The poorly-drawn transistor open in case of over voltage in one or more cells. The current heats the fuse opening it.

Regards,
Maciej

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