Raise XL6009 maximum voltage - Page 1
Forum section: electronics / projects

author: Stephen37
author_rank: Contributor
timestamp: October 05, 2016, 02:09:59 pm
content: Hello guys,Yesterday I wanted to get out 44V (I only need50-100mA) out of a cheap XL6009 module which has a 50V output capacitor. The maximum voltage I could get out of it with 5V input was 37.7V.I checked the datasheet and the voltage is set by VOut = 1.25*(1+R2/R1), on the board R2 is a 10k 10-turn potentiometer and R1 is a 330-ohm resistor. Also, I looked at the maximum voltage output of the XL6009 chip and the first datasheet I checked had 60V specified.Therefore I turned the 10k potentiometer to 8k andchanged the 330-ohm original resistor to a 220-ohm resistor to get a theoretical maximum output voltage of 46.5V .Of course I was stupid and the flux which I didn't clean started vaporising on the SS34 diode on the board after a second and the output was the same as the input voltage. I desoldered the diode and put an N4007 instead to test whether the switching still works, and I could get 33.3V out with the new setup but the diode and chip started to get hot very fast because I suppose the N4007 is not fast enough for 400khz. (luckily I didn't burn the chip)I tested the SS34 diode and I confirmed that it became open on both ways after only 1-2 seconds of overheating.This is the first time I tried to hack a boost converter and because I didn't check the diode first I didn't realise that the SS34 is rated for only 40V.Now here is why I am making this topic :Today I searched again for the datasheet of the Xl6009 chip and I found another datasheet that specifies only 42V output for the same chip, same datasheet.Behold the beauty of chinese products :1.http://www.szxinna.com/pdf/20117302753.PDFis specifying 42V2.https://www.pollin.de/shop/downloads/D351434D.PDFis specifying 60V3. There is no datasheet for the XL6009 on the website of XLSEMI...Now I have no idea whether I should try to get out 44V out of the converter or not... Unfortunately I don't have a 50/60V schottky diode at hand to test whether the diode is my issue or not...Furthermore I have to note that there is another version that has a 50k R2 potentiometer and a 1.3k R1 configuration on the internet (probably older) which has a theoretical maximum output voltage of 50V but still has the SS34 diode.Has anyone tried to do the same thing and come to the conclusion that the chip is capable of only 42V ? (the modules sold on ebay are actually set to a maximum of ~38V)Did I miss something ?

author: hasithvm
author_rank: Contributor
timestamp: October 05, 2016, 08:17:40 pm
content: I'd go over the components and check the voltage rating for everything if you're gonna keep hacking at this....that 50V cap is waay too close to your outputs for my liking.

author: F1Andy
author_rank: Newbie
timestamp: February 17, 2019, 02:45:30 pm
content: I know this topic is old, but for anyone else looking for answers:It is fairly easy to increase the voltage by changing the diode to an SK6 (See the XL6009 data sheet for alternatives) and changing the preset for 20K instead of 10K.The output capacitor is only rated at 50V, so needs to be swapped for a higher voltage rating. I removed it and added a 100V leaded capacitor across the output terminals. Running at 55V 100mA output for a tube headphone amp.The XL6009 is rated to 60V, but I haven't risked getting too close to that limit.Andy