MAX1044 to the maxx: 8,97 V -> 19,9V ?? how can this be?

[zjokka]

RG's article on the max1044 really made me decide to feed my pt-80 the 9V I have available and pump it up internally.
I kind of overcame my own stupidity of ordering the tiny version of the chip as I did succeed in soldering on longer legs.

Now I read the article and the lower the voltage drop the better. So I went and found what I think are Zender diodes that measure 0,3V voltage drop. The resulting voltage is more than double of the input!

I haven't even tried using it with the box yet, but when I first tested it it I heard oscillations on the radio.
Or just take the 19,9V and be happy? Nah, very curious..

j

[zjokka]

 

ok, i'll just be happy then

[Paul Perry (Frostwave)]

Stay happy, but those diodes are probably schottky diodes, not zener.

[amz-fx]

Load the output of the Max1044 with a 10k resistor to ground (temporarily) and measure the voltage across the resistor. I suspect you will find that it has dropped below 18v.

Without a load, the voltage will build up on the output capacitor to an artificially high level that cannot be supported once a load is connected.

regards, Jack