Forum: Analog Circuits NTC at LTC4006 charge controller

von K.M. Schulte (Guest)

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the LTC4006 charge controller for Li-Ion batteries supports a NTC for 
the temperature check of the batterie to be charged. The standard value 
for the NTC in the datasheet is 10k.

Now we have got a ready-made battery equipped with a 300 Ohm NTC.

We expect resistances between ~130 and ~900 Ohm for an allowed 
temperature range for the battery of 0° up to 50°C.

I get the controller working for NTC values down to 220 Ohm, but not 

Has anybody experience with this special configuration?

Thank you in advance!


von renard (Guest)

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There is no way to use a low resistance NTC directly. Even if it's not 
mentioned in the datasheet, I would not expect to draw more then some 
100µA from NTC pin without affecting the resulting voltage significantly 
(not reaching the threshold levels of NTCVR*0.5 resp. NTCVR*0.125).

Therefore replace the NTC or use an active circuit for decoupling.

von K.M. Schulte (Guest)

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Thank you for your appraisal!

That is what I suspected. Unfortunately it is not possible to change the 
NTC. So I will have in fact to prepare a work-around circuit.

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