LM51551: Make 200V high power supply with LM51551 for Si APD

Hi Kent,

Thank you for your interest in the LM51551. It is need some time for response due to holiday.

Any update is appreciated! TKS~ Kent

Hi 

Thank you for your patience. Since the engineer responsible for this device is on holiday, I will try to answer your question.

You can adjust the output voltage through the feedback resistor, but due to the maximum duty limitation, you may not be able to get the voltage you need, so we recommend the second solution for high voltage.

For the output cap ， In addition to the two points you mentioned, I will add one more point. It will also be affected by your output ripple requirements.

BR Dehuan

Hello kent, 

Thank you for your patience. Could you please share the specs for the input voltage range and the output current needed in the system? As you would like to bias an APD sensor, I would expect a low output current. I'm looking forward to your answer. 

Kind regards, 
EM

Hi EM,

If possible 5V input voltage will be my best choise for tight space, of course we can make a 12V boot circuit if need.  AS you mentioned, APD sensor, only need to <1mA ouput current.

Best Regards,

Kent

Hello, 

Thank you for the feedback. As you plan to have a pretty low input voltage, I would suggest to use the approach with the charge pump, like in figure 10-8 . At this link you can find a reference design with a similar device to the LM51551 (https://www.ti.com/tool/PMP8621). To size the components in your design you can follow this app note https://www.ti.com/lit/an/snva824/snva824.pdf?ts=1641982671622 

Kind regards,
EM