LM5146-Q1: Can the LM5146-Q1 IC be used as fly-buck converter?

Rohan Shevade

Prodigy 75 points

Part Number: LM5146-Q1
Other Parts Discussed in Thread: LM5146, LM5160, LM5160-Q1, LM25184

LM5146-Q1 meets the following requirements to be used as a fly-buck.

1. Synchronous rectification.

2. Diode emulation feature at light loads can be turned off.

My requirements are as follows: Gate drive application (HV Inverter)

Input 10-18V

6 isolated outputs: Three 15V and Three -8V (each output at 100mA)

Non isolated output may be +5V or any other voltage.

Just wanted to confirm if it can be used?

Please provide a reference schematic for the same.

Thanks!

over 3 years ago

0 Timothy Hegarty over 3 years ago

TI__Guru 73452 points

Hi Rohan,

We typically need negative current limit on the primary to have secondary side current limit. The LM5146 does not have this, hence we have not tested it with Fly-Buck. Given the low current levels, you might consider a flyback design.

Regards,

Tim

0 Rohan Shevade over 3 years ago in reply to Timothy Hegarty

Prodigy 75 points

Hi Timothy, is there any other IC that would function well as a fly-buck?

0 Timothy Hegarty over 3 years ago in reply to Rohan Shevade

TI__Guru 73452 points

Hi Rohan, take a look at the LM5160 65V converter that can be used as a Fly-Buck.

Regards,

Tim

0 Rohan Shevade over 3 years ago in reply to Timothy Hegarty

Prodigy 75 points

Timothy, I have tried LM5160-Q1 but the current limit on that is slightly lesser(2A). Given the number of secondary windings, I would require somewhere in the range of 3A or more. Can you share your email id so that we can discuss there?

0 Timothy Hegarty over 3 years ago in reply to Rohan Shevade

TI__Guru 73452 points

Hi Rohan,

I assigned this to another group who manages isolated. They should reply shortly. Have you considered using a flyback instead of the Fly-Buck, e.g. LM25184? Also, what is the current requirement of the 5V non-isolated rail? The isolated power is 23V x 0.1A x 3 = 6.9W.

Regards,

Tim

0 Rohan Shevade over 3 years ago in reply to Timothy Hegarty

Prodigy 75 points

Timothy, can you share your email address? I am exploring fly-buck capabilities for a proof of concept project. We can discuss further over email, you can forward my request to the appropriate group

0 Timothy Hegarty over 3 years ago in reply to Rohan Shevade

TI__Guru 73452 points

yes, it's tim.hegarty@ti.com

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LM5146-Q1: Can the LM5146-Q1 IC be used as fly-buck converter?