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Observing heating issues

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FreshmanNewbie

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I'm using this Boost converter.

Below is the schematic:enter image description here
Layout:
enter image description here
The IC , inductor and diode immediately gets heated up. Any idea why?
Also, there's always a 500mV drop on the output voltage. For 9V output, 8.5V is available when load current goes above 0.5A.
Any idea why?
 

Hi,

please also show the bottom copper layer of the PCB.

added:
Datasheet: pin11: "Do not leave floating". But in your schematic the resistors are not assembled.

Why is your C37 value that far from datasheet recommendation?

Klaus
 
Last edited:

Your schematic contains an extraneous text indicating that L2 is capable of handling 4A ( peak value? ); Should we assume that you have already reviewed the specification of L2 against the device actually mounted on the board ? BTW, nowardays I no longer design SMPS without performing electrical simulation before, did you do that ?
 

Since you have not shown any signals, comparing your ground layout with the datasheet, I wonder if you have reasons for making such drastic changes to crosstalk and isolation of input and output and bridging Analog with Power ground. I would expect you have some resonant instabilities drawing more than rated current.

1680807494299.png
 

What is the Fsw ? Oh - 1MHz

the capacitance in the choke may be upsetting the switching losses - also all COTS chokes are very lossy - esp at 1MHz

your diode may not be a fast enough type for 1MHz
 

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