LM3697: Boost converter output reach out to 40V when initially start up, but we set OVP = 24V (no load)

Hi Roy,

I didn't see the start up waveform from your figure.

Could you please kindly ask our customer to catch the waveform of initial Vout and send it to us?

BR

Patrick Yao 

Hi Roy,

Do you have more questions? If not, I'll close this case later.

BR

Patrick

Hi Patrick,

May you help use EVM to do the start up test when LED open(no load)? I applied the EVM, but I'm not familiar with GUI and it burned out. 

We are wondering if there is 40V when power start up when no load.

Regards,

Roy

Hi Roy,

What do you mean of "burned out"?

BR

Patrick

Hi Patrick,

The chip looked damaged. I see the Vout = 1.5V~2.5V when we Vin = 5V.

Regards,

Roy

Hi Roy,

Can you share the schematic of customer design?

BR

Patrick

Hi Patrick,

Sorry that I forgot to attach the schematic.

Roy

Hi Roy,

Could you please help to check two points as below?

1) What's the input current limit of your source?

If the input current is large and it reaches the power source limit, then somewhere must have a circuit short. 

I think if the device is damaged, the output voltage should be equal to Vin according to your schematic.

2) Have you checked the capacitors?

I reviewed your schematic and I think the capacitor voltage might be too limited. I recommend to check if these capacitors are still fine and if possible, 50V capacitors are better choices.

BR

Patrick