Hi Gordon - It sounds like your boost supply is powered from the regulated micro supply= .. Can you power it from the unregulated supply? What is the unregulated sup= ply? Is that what is actually drooping? What sort of regulator is the 5V re= g anyway?=20 It's amazing how one question cascades isn't it :o) Stephen -----Original Message----- From: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu] On Behalf Of= Gordon Williams Sent: Friday, 14 October 2016 9:33 AM To: pic microcontroller discussion list Subject: [EE] power supply transient droop I have a boost converter that I am switching on with a microcontroller . T= he draw on the power supply goes from about 50mA to 2A and the power supply= drops about 1.3 volts for 10ms during turn-on. Power supply is 5V. During the power dip the voltage goes below the voltage allowable for the m= icrocontroller per the data sheet. The LEDs also flicker which I don't lik= e. I tried adding more capacitance at the microcontoller 330uF and this only i= mproved it slightly by about 100mV. I thought of adding a resistor or diode in the power line to the the microc= ontroller to see if that would improve things with some bulk capacitance at= the micro. Is there a standard way to handle this to get over the short l= ow voltage period? Gordon Williams -- http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/chang= e your membership options at http://mailman.mit.edu/mailman/listinfo/piclis= t --=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 .