Hi,I am making a buck step down DC regulator using the LM2576T-5V IC. Main aim is to regulate output from solar panel 9V to 5V. Max current is around 1A.Using a 100uH colour coded inductor, i see 9V 0.4A converted to 5V 0.3A. The efficiency is around 50% What are the things i should look out for? Should i change to another inductor?I am using the following parts: LM2576T-5V100uH colour coded inductor100uF 16V cap1000uF 10V cap1N5401 DiodeMBR160 Schottky 1A Diode
I'd try a some what larger inductor; the reference design uses a 330 uH. Why do you have the 2 diodes? Are they in parallel? The 1n5401 is ok for a flyback diode, but the MBR160 is a bit undersized. Remember that the peak current in the diode can be much higher than the output current of the supply! Is anything in the circuit getting hot (like the diode?)
Did you measure the inductor currently correctly? The power delivered by the 9 volt source is 9*Iave, not Ipeak or Irms. Is the inductor saturating?
