efficiency in boost converters

[volyaire]

I made a boost circuit using the LMR 64010 chip to boost 7.5v to 44v at only 3mA.  It works well but consumes 41mA from the 7.5v battery which is way too much. My question is if I increased the value of the 10uH inductor to say 20uH or more will it improve the efficiency of the circuit? If I had some spare inductors I would test it myself, but I haven't.

[Zero999]

It might help, as long as it has an equal or lower ESR.

Extrapolating the efficiency curves on the data sheet, 43% seems similar to what you should expect from this IC, at the input/output voltage and current you describe.
http://www.ti.com/lit/ds/snvs736b/snvs736b.pdf

Without a transformer, 7.5V to 44V requires a duty cycle of >83% so you shouldn't expect great efficiency, but it's possible to get better than this. You need a boost converted designed for lower current operation.

[soubitos]

It might help, as long as it has an equal or lower ESR.

Extrapolating the efficiency curves on the data sheet, 43% seems similar to what you should expect from this IC, at the input/output voltage and current you describe.
http://www.ti.com/lit/ds/snvs736b/snvs736b.pdf

Without a transformer, 7.5V to 44V requires a duty cycle of >83% so you shouldn't expect great efficiency, but it's possible to get better than this. You need a boost converted designed for lower current operation.

Doing some research on boost ic's myself lately, i realized that in current draw under certain levels, most ic's performances drop significantly

[Paul Price]

This boost chip LMR 64010 spec shows a max output voltage of 40V and the OP is attempting to get 44V out.

[volyaire]

I am getting 44v out

[ocset]

Yes youre stressing lmr64010 and shouldnt use it....pretty much all  practical smps are very inefficient when at low power.
Also, the switching frequency is 1.6MHz which wont help......though i assume it acts in burst mode at your low power leve.
Also, i am looking for the bias power draw of the chip
http://www.ti.com/lit/ds/snvs736b/snvs736b.pdf
..oh its only 3ma...so i would put it down to the high f(sw) and the fact your overstressing it and could be putting much leakage current through the internal fet.....also, the operation at low power level.

[soubitos]

It also doesnt help when you have a very low starting voltage.. the fact the chips CAN boost say from 5 top 20V doesnt mean they will be efficient at such setting... I use MT3608 powered from 1S lithium batteries... whith fully charged battery and output at 5-9V there is no problem drawing 1A (chip is spec'ed up to 2A)... doing the same at 12 V is trickier, chip starts heating up ... over 12V efficiency drops further and you can draw 200-500mA up to 15V maybe but its best not to stress it so far... I think at 24V (from 4.2V) you can draw as much as 50-100mA continuously but its still hot... I am not an expert per se, just sharing my experience!