I am planing to design a controller for a universal washing machine motor based on the TDA1085c. While designing the schematic, i have some problems to understand the sizing of some resistors.
Here you can find the datasheet of the TDA1085C.
The resistors to which I refer, are R10 for Pin10 and R15 for Pin15. In my opinion it is not very good described how to size these resistors.
Does anyone has a clue?
Best Answer
From the datasheet one might conclude that R10 is tuned by measuring. (On page 3 you have the section for VOLTAGE REGULATOR which can give additional clues)
And R15 is involved in a calculation with the C14 capacitor to determine que frequency (albeit the formula is not given). On page 3 you have the specification for pulse duration in the TRIGGER PULSE GENERATOR SECTION: Trigger Pulse Duration (CPin14 = 47 nF, RPin15 = 270 k)
You can also start with the values used in some existing circuit like (which has also 47nF for C14):
Beware the given schematic is for 230V.