LM2577: LM2577

Hello,

Thanks for using the e2e forum.
Do you know the maximum load current of this application?

Based on this, I can check if LM2577 is the best suitable part recommendation and also send links to some material on how to design a Boost converter.

Thanks and best regards,
Niklas

The maximum current will be used between 1A and 1.5A.
The DCDC I inquired about will be used as a power source for the opamp, so I would appreciate it if you could also introduce the negative power DCDC to be used together.

Thanks for the quick feedback.

For peak load current of 1.5A, the LM2577 might already reach its current limit.
I would recommend a controller with external switch instead to support higher current requirements.

LM5155 would be the best suitable part for this.
Here is an app note on how to design a boost controller:
https://www.ti.com/lit/an/snva824/snva824.pdf

As for your second request:

CHI JONG JANG said:

I would appreciate it if you could also introduce the negative power DCDC to be used together.

Does that mean you need a positive (+60V) and a negative (-60V) output rail?
A boost converter can only provide one out output.
If two output rails are required, you would need a flyback topology with a transformer, which can then supply more than one output rail.
The LM5155 controller can be used for such an application as well.

Best regards,
Niklas

Thank you for the recommendation.
I tried to use the calculator as below by changing the condition of the output to 90V-1A.
Do you think we need a correction?

Thanks for the update.

The boost ratio from 12V to 90V is still within the duty cycle capabilities of the device, so this is within the device limits.
The entries in the calculator still look okay to me, so I do not see any necessary changes.

Best regards,
Niklas

Please keep in mind that with 90W output power, MOSFET and inductor part can heat up quite a bit. Components should be able to support these peak current and voltage levels.

Best regards,
Niklas