LM2587: typical boost regulator application

Hi
It should be okay with the 10Ohm load. Would you please show us your layout ?
The engineer in charge of this device is out of the office, he will be back in the office next week
Regards,
EL

My circuit is a bit different from the post. But basically the are the same circuits. Please check the schematic and PCB layout. 

for the load 330R (the current is 106mA), the circuit is working fine. Switch ON and OFF, no problem. Please check the waveform.

Channel 1: Vin.

Channel 2: Vout

Channel 3: PIn four ot the 2857, the Switch node.

Hi Zhongwen
Could you tell me P/N of the diode D1? the diode D1 must be rated for a reverse voltage greater than the Vout=48V. and the average current rating must be greater than load current.
You can check it.

manufacturer part number is STTH4R02U for the diode.
My main issue is the circuit can be switched ON without load or very small load current 200mA.
If the load current is big like 600mA, the circuit can not be switched ON, the voltage drops, chip is not regulating.
If the circuit is switched ON without load first, then connect a big load 600mA, the circuit is working ok. Only with a little buzzy noise.

Hi Zhongwei
there is a possible reason. Could you check you Vin power supply's current limit setting? maybe you set a low power supply's current limit.

my current limit is 6A

OK

to help me analyze this question, Could you do some test and post some waveform?

I want you to save this point waveform: Vin SW and Vout. Please put voltage probe as I draw in the layout. if you can test inductor current at the same time, it is the best.

(1) in open load, test start up waveform and steady waveform.

(2) in heavy load like 600mA, test the start up waveform and steady waveform.

Hi Zhongwen
Did you solve the problem?
and maybe you can change a smaller Vout capacitor.

there is some testing data for my circuit. Please see this post on the bottom
e2e.ti.com/.../187902