On 28 January 2015 at 05:50, wrote: > Well, Isaac led me down a half hour Black Hole at Richtek, following his > post in the thread on "RE: [EE] Charger and power circuit for mobile > equipment". > > In the process I came across this application note, worth looking at for > anyone doing mains supplied LED lighting ... > > http://www.richtek.com/assets/AppNote/AN022_EN/AN022.pdf > > All about minimising light flicker in LED lighting applications. > > A useful application note. At first glance it looked like it was very basic (use small Cin and large Cout for good PF and low ripple). But it went by way of hill and valley ccts and other stuff and ended up at their 'rather nice' dual converter IC with PF correcting boost converter and separate buck converter with 2 inductors and all small enough to fit in a PAR16 bulb. Worth looking at. I did note a dangerous rabbit hole - Page 15 re fig 21 " ...Since the valley fill buffer capacitors don't see the full rectified line voltage, 250V types can be used. ..." This is true "enough" for the basic mains voltages but leads you away from the narrow path of X & Y rated caps for mains use, with spikes and surges and Murphy standing waiting. Maybe OK if it is "only a light bulb". Maybe that's waht happened to the "cheap" Chinese bulb that I have yet to return to the local retailer 'to see what happens' (I have box and receipt). The 3 x datasheets at the end look worth a look. Still 'coming to grips' with their "Linear LED Driver for High-Voltage LED Lamps " http://www.richtek.com/download_ds.jsp?p=3DRT7321&utm_source=3DAN022&utm_me= dium=3DRTWWW&utm_campaign=3DAppNote Russell --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .