Comparator for supply range 16.8V

Thread Starter

Vindhyachal Takniki

Joined Nov 3, 2014
535
1. I have a battery powered application which is powered application from 4S li-ion cell. (12V - 16.8V). I need a comparator for this. Comprator output will drive a mosfet FDS6690A, which is basically in current path.
2. Comparator has to be very low powered since it is battery powered application. I have checked TLV3701 from texas instrument. Datasheet says it for upto 16V, but absolute max can go upto 17V. Can I use it here?
3. Another option is to use LT1716(upto 44V), but its current can upto 85uA at 12V. So I haven't consider it yet.
4. Any other very low powered comparator for 16.8V supply & to drive FDS6690A.
 

Thread Starter

Vindhyachal Takniki

Joined Nov 3, 2014
535
Attached is the circuit, if I use TLV1701. Have to drive a mosfet which will cut the load current. Input of comaprator has to compare between 3.3V & 1.5V.

Only problem is at V+ side of comparator, wich exceeds 16V limit.

Looking for some series diode which can be added. Problem in that case may be that series diodes themselves have very low Vf at current in uA range. e.g http://www.digikey.com/product-detail/en/1N4148X-TP/1N4148XTPMSCT-ND/789335 has drop of 0.2V at 10uA


Problem with open drain, is everytime current will be consumed when output is low. as in attached circuit
 

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ErnieM

Joined Apr 24, 2011
8,047
Your schematic has no comparator shown.

I know you need need to choose one, but for that we need to see where you are using it.
 

Thread Starter

Vindhyachal Takniki

Joined Nov 3, 2014
535
Attached is my circuit.
1. MCU takes one input(J3, voltage), do some processing & then turn P1.7 high or low. When P1.7 is high, it gives high to comparator, which in turn on the FDS6690A, & turn off if p1.7 is low.
2. Can I turn on/off mosfet FDS6690A directly by MSP430(3.3V)? Datasheet says VGSmax = 3V, when VDS=VGS & IDS = 250uA.
In my case max Vds will be 16.8V & max current will be around 7A.
If yes, then I can remove comparator.
 

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