100v to 3.3V, what mode of step-down should be selected？

Kevin Zeng

Intellectual 2060 points

Other Parts Discussed in Thread: LM5164

100v to 3.3V, what mode of step-down should be selected？

over 3 years ago

0 Andy Chen over 3 years ago

TI__Mastermind 34045 points

Hi Kevin,

Pls check if LM5164/63 OK

B R

Andy

0 Kevin Zeng over 3 years ago in reply to Andy Chen

TI__Intellectual 2060 points

Hi Andy,

thanks for the your answer, LM5164 can achieve this function, but I want to know how to consider the choice?

because there are many devices that can achieve this function, they power control mode are different. So I more want to how to consider in this way.

Thank you.

0 Andy Chen over 3 years ago in reply to Kevin Zeng

TI__Mastermind 34045 points

Hi Kevin,

The duty cycle is quite small for 100V to 3.3V, so COT mode or voltage control mode is better solution.

B R

Andy

0 Kevin Zeng over 3 years ago in reply to Andy Chen

TI__Intellectual 2060 points

Hi Andy,

Thank you your remind. Can you explain more about COT mode or voltage control mode is better solution not current mode?

Thank you again.

0 Andy Chen over 3 years ago in reply to Kevin Zeng

TI__Mastermind 34045 points

Hi Kevin,

the duty cycle is only 3.3% for 100V to 3.3V step down conversion, If the converter has Ton_minimal about 150ns, the Fsw should be below 220KHz, the inductor size is big because of low Fsw. COT and Voltage has smaller Ton-min because it doesn't need to sense the switching current as peak current control mode.

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100v to 3.3V, what mode of step-down should be selected？