LM51551: I am struggling to operate boost convertre using LM51551

This is the LM5155 calculation values we used in the design. 

5582.LM5155_56_Quickstart_Calculator_for_Boost_Converter_Design_V1_1_1.xlsx

Hi Faiz, 

Thank you for using e2e forum.

Could you also please share the waveforms like SW, CS vs Vout and Vin?

Best regards,

Mounika

we are trying but currently it is hard to manage oscillioscope. is there anything we can test using DMM only ? 

Hello Faiz,

You can measure the VCC with a DMM, but for working with a switch mode power supply, testing with a scope is mandatory.

Best regards,
Brigitte

Hi!
Our PCB is under testing with PCB Manufactuing company. I am able to get the waveforms on the points you mentioned. please find it in the attached video 
https://pcbwayfile.s3.us-west-2.amazonaws.com/mail/25/06/17/201911571f73ab0c61b044ec993eb95e462fdc1658113.mp4

You can find the waveforms on these timestamps
0:16 SW
0:44 CS
1:24 OUTPUT

it look like there is no data on CS but there are pulses on SW and OUTPUT.
Please guide me to make this circuit work. 
Thank you very much

Hi Faiz, 

Thank you. However, I would need to check all these waveforms at the same time. Could you please help to attach all three probes and send the snapshot of the scope.

Best regard,

Mounika

Hi!
This is video they recorded by placing prob on SW and output. the blue is output and yellow is SW. 
https://pcbwayfile.s3.us-west-2.amazonaws.com/mail/25/06/19/202725372bd5766b5260a4eef8aca0b4e00c642ae1483.mp4
on CS it is already zero all the time and input is stable 30V. 

if this is not correct. give me few days. i asked them to ship the pcb to me. i can test it on oscillioscope in my own lab. 
Thank you

Hi Faiz, 

In the boost circuit, if you see 30V output which is same as input voltage = 30V which means that the device is not switching.

• Check the value of VCC ( >5V), UVLO (>1.5V).
• Please check the SW (TP1) with the scope. Check if there is a PWM signal.

Yes, like I mentioned I would need to check all these waveforms at the same time.

Best regards,

Mounika

ok, I have oscillioscope of 2 channels. so i can measure 2 waveforms at the same time. I will receive the PCB in 2 to 3 days. then I can check them will let you know. Thank you for support

Hi!
I have applied 18V and i can get 24 V output. i think its issue related to feedback resistors. the calculator in excel file was not able to update feedback resistor values so we used the same. 
Now i am about to update the feedback bottom resistor to 315 ohm to get 150V output. can you help me confirm if this is correct ?
Thank you