I'm wondering how to select a correct zener diode value for this led driver I am using RT4533AGJ6 (link to datasheet). My understanding of boost converters is limited, although I understand that there is an internal switch that charges up the inductor and when switched off, the inductor discharges onto the load…through the zener diode, which is to my point. The datasheet does not give any values for breakdown voltage, let alone why its required.. i did some further searching on other led driver datasheets and ran into an additional issue, the reaction/reset speed of the zener diode, which is of course dependent on the switching speed.
To make matters worse, I had contacted a customer service representative from a electronics warehouse, he said that it didn't matter what value diode I choose….which just seems silly and must be wrong in some way.
Best Answer
This is a boost converter topology. The diode should be Schottky, not Zener. The reference design for RT4533 has a bill of materials, where D1 is a Schottky.
The symbol in the datasheet is for a Zener. I blame lack of proofreading.