STM32F407 transformer design

utpal kumar · ‎2017-05-04

Posted on May 05, 2017 at 08:11

Dear All

As discussed on our call, i am looking for some support in verifying our transformer design as i am having some trouble in generating the output and I have doubts on the transformers we already have.

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> Processor used : STM32F407

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> Use case : 48 V DC on the transformer primary is switched by the controller to generate 1600 V Peak to Peak output on the secondary in 160KHz frequency.

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> Issue : When the transformer is loaded, the clock of the STM controller changes and there seems to be some disturbance to the power section too.

> When the primary voltage is reduced from 48V to a lessor voltage like 5V-12V, depending on the board, this works as expected with lessor output P2P in the secondary.

Thanks

AvaTar · ‎2017-05-05

Posted on May 05, 2017 at 09:32

> Issue : When the transformer is loaded, the clock of the STM controller changes and there seems to be some disturbance to the power section too.

The issue is your design (schematics, PCB layout), with has inadequate EMI resilience. Galvanic or magnetic coupling induce voltages above the specified limits into the MCU. There is nothing wrong with the F407.

Consider galvanic isolation.