LM5101A High Side Driver

Hello Sujan,

There are possible issues with this schematic. According to the recommended conditions, the V_DD and HB pin should be operating between 9V to 14V. It is necessary to ensure the V_DD and the HB pin voltage stays well below the absolute maximum rating of 18V (nominally should be 12V). In case of any V_DD supply overshoots (above 18V), it will definitely affect the driver operation.

LM5101A is designed to drive NMOS switches. A more common approach can be replacing the PMOS with an NMOS switch. Instead of grounding the HS pin there, one can then connect the HS pin to the Switch node, like in a regular boost configuration.

Regards,

Sourav

7144.sch2.docx

Hello Sourav

Thank you so much for clearing my doubts on the LM5101A. Clearly i see, i would not be able to use this as my MOSFET gate drive.Regarding your suggestion to connect body to source; I can't connect the body of the mosfet to either source or drain due to the leakage issues. As i mentioned earlier it is a multiple output converter and hence i need to connect the body to highest voltage to prevent leakage across two outputs.

So, for the specs mentioned above : could i use UCC27512 instead.
Boost Max output : 12V-16.5V
IN+  input gets the PWM signal (0-3.3V). I want the OUT signal level shifted to drive the PMOS gate (0-16.5V). This gate driver has max ratings of 20V...could you kindly let me know if this is good choice for my application.
I have attached the schematic for reference.

Thanks
Sujan

Hello Sujan,

The UCC27512 will be a better option to go with your application.

Thanks,

Sourav

Hello Sourav

 Thank you so much ! I shall shift to UCC27512 .

 Kindly let me know in case you have nay application note for this IC. I have the datasheet from TI website.

Thanks again

Sujan

Hello Sourav

 Forgot to ask one important question before i proceed.

 My PWM input is 0-3.3V  form the TI C2000, which is applied to the IN+ pin of UCC27512. Since i want the output to swing between 0-16.5V , i would connect the VDD supply to 16.5V (max voltage). Since the input (IN+:  3.3V) and OUT (VDD domain :16.5V) are different power domains,  will the IC take care of the input being level shifted to VDD level, 16.5V in this case ?  Kindly let me know

Thanks

Sujan

Hello Sujan,

Yes it will. The OUT voltage level (high) of the driver should be close to the Vdd value.

Regards,

Sourav

Sujan,

Regarding the application notes, i am not aware of any document for the UCC part but you can find application notes for other drivers like LM5113.

Regards,

Sourav

Hello Sourav

 Thank you...I shall keep the OUT swing to VDD value in my case. Input of 0-3.3V --> OUT of  0-16.5V (vdd).

Thanks

Sujan