Solution Finder


Posted by: GPM on Fri, 08/08/2008
DI-185 1. wrt the mentioned design idea, what would be the lowest output voltage while still maintaining the rqd 350ma load? (before it goes into the output short condition and autostart mode) 2. Rupper and Rlower - what is the analytical relationship of these resistors wrt the output voltage and currents? thnx in advance. best rgds madan


Submitted by PI-Spock on Mon, 08/11/2008
Autorestart is dictated by the voltage at the FB pin. The device enters autorestart mode when the voltage at the FB in approximately 0.72 V (varies slightly from device to device) This means that for the design in DI185 which has a nominal out put voltage of 12 V - This design will enter autorestart mode at approximately 4.3 V.
Submitted by GPM on Mon, 08/11/2008
thanks for the reply. if understood correctly, the loop closes at appx 33% of the output set voltage. Pls advice a way to take it down to 20%. Much appreciated. rgds gpm
Submitted by PI-Chekov on Tue, 08/12/2008
As the ratio is set internally there's no way to force the voltage to stay in regulation to a lower level.