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Use the ADP2118 tracking input to minimize current-sense resistor value?

Question asked by mark03 on Jul 14, 2011
Latest reply on Jul 15, 2011 by mbhatt

I'm contemplating the ADP2118 for a high-power white LED driver.  The usual issue with buck regulators in this application is the [relatively] high reference voltage into the error amplifier.  Getting 0.6 volts from a current-sense resistor means lots of wasted power in I^2*R loss.

 

From the datasheet, it looks like I could drive the TRK input to something like 50 mV, making that the effective reference voltage for the error amplifier.  Then I could use a small sense resistor and everything is wonderful.  Are there any problems with this scenario, or should it just work?  (I do realize the FB/TRK offset voltage means the fractional uncertainty will be larger.)

 

Thanks,

 

Mark

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