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# LM5169-Q1: LM5169

Part Number: LM5169-Q1
Other Parts Discussed in Thread: LM5169

HI

In the Typical Fly-Buck Converter Application Circuit given in the LM5169 datasheet, can we get VOUT1 = 5V and VOUT2 =12V. For this what transformer part we need to select.

Also if you have any excel sheet for this please do share it which will be helpful during our simulation.

Also can we get 0.65A at VOUT1 and VOUT2 or the output current will be divided between VOUT1 and VOUT2.

Thnaks

Harish

• Hi Harish,

Thank you for your question. What are your input and output loading conditions? These will help us better assess the proper components for your application. Additionally, the datasheet for the LM5169 datasheet gives a comprehensive step-by-step procedure to designing a fly-buck circuit for this device starting on page 17.

Thank you,

Joshua Austria

• HI

Below is our requirement

Vin = 120VMax

Vout1 = 5V ,0.65A

Vout2= 12V .0.65A

Thanks

Harish

• Hi Harish,

Apologies, I also need your switching frequency as well. Additionally, the output current of your outputs will be limited by Equation 11 in the datasheet on page 18.

Thank you,

Joshua Austria

• Hi

Switching Frequency is 500Khz

Thanks

Harish

• Hi Harish,

I will send you what I find tomorrow. In the meantime you can take a look at the LM5169 datasheet for the step-by-step procedure if you want a quicker result.

Joshua Austria

• Hi Harish,

Calculating your values using the datasheet equation yielded invalid results. You can use these resources to evaluate possible configurations for this part.

Fly Buck Design

Turns Ratio

Additionally, in terms of an excel calculator, I found that most of the equations for other device flybucks work for this device as well. You can use this excel calculator to help figure out transformer configuration.

Thank you,

Joshua Austria