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In the datasheet for an overvoltage protector (TI BQ771815) there is a device I don't recognize:

WhatIsIt

It is used in the datasheet as a fuse which can be opened by an external signal from the overvoltage protector (in this case, by pulling the signal connection to ground). It is used to protect Lithium battery packs. This is from Page 10 of the BQ771815 datasheet:

diagram

What is this device called? Who produces them?

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    \$\begingroup\$ No, I don't think so. The lower connection is connected to an Open-Collector output which indicates a failure and should blow the fuse. If I understood right, if the resistor is connected to GND, it heats up the fuse and destroyes it. The component is found in the following datasheet ti.com/product/bq771815 on page 10 \$\endgroup\$ – Botnic Apr 2 '15 at 16:35
  • \$\begingroup\$ Thanks for that link. I agree with your assessment. I don't know what the part is, though! I'm going to keep an eye on this question. \$\endgroup\$ – bitsmack Apr 2 '15 at 16:56
  • \$\begingroup\$ Maybe this is a normal fuse with external resistors with resistance high enough to not blow them selves up but only the fuse? Just a guess, because none of the usual fuse suppliers seem to have the kind of fuse depicted. \$\endgroup\$ – Dejvid_no1 Apr 3 '15 at 18:16
  • \$\begingroup\$ @Botnic I put a bounty on this question. I hope you don't mind! :) \$\endgroup\$ – bitsmack Apr 8 '15 at 5:24
  • \$\begingroup\$ The schematic symbol in the data sheet extract below looks more functional than the one in the schematic above. The above arrangement would keep draining or charging the battery through the resistor even if the fuse had opened causing the dreaded under or over voltage Li cell condition eventually. \$\endgroup\$ – KalleMP Apr 9 '15 at 21:11
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This element is called Self Control Protector (SCP) and is produced for example by Dexerials

enter image description here

When the heater is activated and melts fuse element to stop overcharging, the flow of electric current through the heater stops as soon as the charging circuit is cut off.

(Source: e2e.ti.com and Dexerials.jp)

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  • \$\begingroup\$ Thank you bitsmack. We found it more or less ;-) Even I know now what element it is, I could not purchase it. But with the equivalent circuit it should work as well. \$\endgroup\$ – Botnic Apr 13 '15 at 19:30

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