the viper37LD is Burned

[PINI BITON]

Posted on March 30, 2016 at 15:01

i have problem all time the chip viper37LD is Burned(Vdd shortened to GND )

I don't have any idea why 

schematic attached 

[reachme247]

Posted on April 04, 2016 at 11:39

[Patrizia BELLITTO]

Posted on April 04, 2016 at 11:52

Hello,

we are contacting the application engineer responsible for this design.

He will answer you as soon as possible.

Best regards,

Patrizia Bellitto

eDesignSuite developer team

[Nickname7392_O]

Posted on April 04, 2016 at 16:41

Hello,

Vdd shorted to ground probably means that the pin has been forced to a current/voltage value higher than its absolute maximum rating (AMR).

This event cannot be ascribed to e-design studio, since several checks are performed in order to avoid that any AMR is exceeded.

I suggest try the following:

replace the damaged sample with a new one, turn on the system and check the VDD voltage on the oscilloscope. 

If, in any input/output conditions, it is constant and in the range 8.5V – 23.5V, the damage could be due to some accidental contact of the VDD pin 

with some higher voltage (check in the PCB if high-voltage tracks run too close to low-voltage ones).

If VDD voltage is above 23.5V, it means that the auxiliary winding is not well designed and the auxiliary turns ratio should be redesigned according to the 

results of e-design studio.