XL6009 fails when a high current is drawn from it

[Sreekanthm101]

I'm working on a battery powered LPG detection project that requires constant 5 Volt supply from battery,so I use 3.7 Volt Li-ion battery and a boost converter XL 6009.I use MQ-6 for LPG leakage detection and the problem occurs during the LPG detection.The sensor takes high current from boost converter and boost converter fails resulting a high voltage in the circuit and even damages micro controller.
Please guide me to resolve this issue and any reply would be greatly appreciated.

 

[KlausST]

Hi,

I assume you did go to several SMPS threads here.

Then you already know:
* you need a proper PCB layout --> show us your layout and your schematic
* you need proper part selection --> give us the exact part names and manufacturer of the used devices.

Klaus

 

[Sreekanthm101]

this is the schematics of the boost

 

[KlausST]

Hi,

Sadly I have to repeat myself.

* show us your layout

--> while one PCB layout my work, another PCB layout may not work. Therefore my request for your PCB layout.

* give us the exact part names and manufacturer of the used devices.

--> while one 220uF/35V capacitor may work, the other 220uF/35V capacitor may not work,
--> while one 330u inductor may work, the other 330u inductor may not work...and so on

My request for your circuit details is not to keep you busy, it is to find a solution for your problem.

Klaus

 

[FvM]

Quite dangerous to use a 100 k potentiometer for voltage adjustment. Better calculate a fixed resistor value for 5V output.

According to datasheet, XL6009 has a minimal input voltage of 5V. This is probably the reason why it doesn't work with 3.7 V input at higher load currents.

 

[dick_freebird]

Only a large bulk filter cap is shown. That can fail to
catch the peak voltage delivered by the boost inductor
(that C*V suggests an electrolytic or tantalum cap,
these tend to have dismal ESL, often poor ESR as well,
and self resonant frequencies in the kHz range).

High current implies high inductor current and high
crest voltage at the filter.

Have you put a 'scope to the supply output at all?
Looked at the ripple there under failing conditions?
For that matter I see zero discussion of any attempt
at debugging, only "broke, boo hoo".

Now, with 3.7V in and a "failed" XL6009, how do you
get more than 3.7V anyway? Only can get there if
the pump is pumping. Otherwise it's just 3.7V, inductor,
Schottky, load (so maybe 3.3V-ish). Just what does
"failed" mean, and where is this purported high voltage
(=?) coming from?