24 Volt Boost converter design

[hemnath]

I am trying to design a boost converter circuit and looking for some IC. Recently I have received samples from Linear technology and Texas instruments.
Samples received: LT1317, LT1930, LT8330, MC34063

My Input voltage varies from 5 to 12V. Output voltage: 24V

First I have tested the LT1930. I have used the circuit which is in datasheet page 8.
Output voltage measured is 25.30V. since I don't have exact value. Which is okay.

Output load connected is 1KOhms. Multimeter measures 8.64V, 147.7mA on input side and output current is 25.30V, 24.5mA.

I think it is 58% efficiency.

how to increase the efficiency? Please suggest me for some IC for better efficiency. I couldn't find it when I surfed.

Meanwhile I shall test the performance of other sample IC and post the results.

 

[schmitt trigger]

This is a very low power output.

Efficiencies are rated for full load, where the IC supply and biasing requirements are negligible. Plus the Mosfet drive current, which at high frequencies can be significant.

For this purpose, there are many controllers with features like "pulse-skipping" and "frequency foldback" options, which dynamically adjust their operating conditions for low output current operation.

Linear, TI, Onsemi, STMicro and others offer such regulators.

 

[hemnath]

I hit a search and tried. But couldn't find the better solution.

Can you suggest?

 

[KlausST]

Hi,

Your question: How to improve efficiency:
--> Draw more output current.

But this won't reduce input power...And I assume you want to reduce the input power.
* select a more suitable converter IC (with burst mode... or one that lowers switching frequency with low load current)
* select low loss inductance
* select low loss capacitors
* select low loss diodes
* use a good PCB layout

*********
You said you used the circuit of page8..
To be comparable you need to use exactely the same inductors, capacitors, diodes, PCB layout, temperature....
Just using the same schematic will give no comparable results.

Klaus

 

[BigBoss]

I tried once this one, maybe more expensive.
https://www.linear.com/product/LTC3130

 

[hemnath]

I tried to use LT8330 and below is the circuit.


When i starts drawing output current, the output voltage reduces. Am I missing anything? Please help.

 

[KlausST]

Hi,

Like in post#4 I assume:
* wrong inductor selection
* bad PCB layout.
... both we can not verify.

Klaus