LM5156-Q1: question about random spread spectrum

Jay wang

Intellectual 2481 points

Part Number: LM5156-Q1
Other Parts Discussed in Thread: LM5156

Tool/software:

hi expert

i saw 5156 has random spread spectrum function and support Boost/SEPIC/Flyback topology.

Q1:i want to check with you whether random spread spectrum can be used in Boost/SEPIC/Flyback?

Q2: it seems like Flyback device seldom support random spread spectrum, what is reason?

thanks

4 months ago

0 Moritz 4 months ago

TI__Genius 12985 points

Hi Jay,

Thanks for reaching out.

Q1: Yes LM5156 has the possibility to enable DRSS. This is then independend on the used topology.

Q2: Devices that are made especially for flyback and operate quasi resonant for example, cannot use DRSS because they have to switch at a certain time. LM5156 however, is not a dedicated flyback device, but a boost controller, that can be used for flyback and SEPIC as well.

Best regards

Moritz

0 Jay wang 4 months ago in reply to Moritz

TI__Intellectual 2481 points

hi Moritz

so if 5156 is used for SEPIC or BOOST topology, DRSS can be used?

if 5156 is used for flyback, DRSS cannot be used?

am i right?

0 Moritz 4 months ago in reply to Jay wang

TI__Genius 12985 points

Hi Jay,

If DRSS is activated, it is always used, independend on the topology.

Best regards

Moritz

0 Jay wang 4 months ago in reply to Moritz

TI__Intellectual 2481 points

ok got it thanks

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LM5156-Q1: question about random spread spectrum