Isolated supply SMPS

[asrikrishnagovi]

Hello, do you have any reference designs or application notes to create an isolated supply (SMPS) for Powering the Isolated side of gate drivers such as 1ED3131MU12H, by supplying +15V and -8V or any other negative voltage. The current requirement is about 1A. The application is a three-phase traction inverter. Thanks and Regards

[AZIZ_HASSAN]

Hi,

Thank you for posting at Infineon community.

I have attached a Push Pull converter design for your reference  which is generally used topology for designing isolated power supply in gate driver applications. 

https://pdf1.alldatasheet.com/datasheet-pdf/view/731999/IRF/IRAUDPS1.html

Please answer following question, so that we could help you in much better way.

1) What is the DC link voltage and what isolation voltage you need in power supply.

2)  Any specific reason to select 5.7KV isolated gated driver IC.

3) What is the output power requirement from power supply and what efficiency you are looking for.  

4) Do you need two separate output (positive and negative ) from power supply or you wish to take a single positive power supply (lets say 25V) and then divide it to positive and negative voltage( lets say +15,-10 V) on gate driver.

5) What is the rating of the traction inverter.

BR,

AZIZ HASSAN

[asrikrishnagovi]

Thanks for the Reference design, here's the answers:

1. DC Link voltage Maximum is 400V during Regeneration, isolation voltage is not decided. 

2. The isolation voltage wasn't chosen for any specific reason, just provided that gate driver as an example. Would like information about the selection criteria on isolation voltage levels provided by gate drivers as well.

3. The output power can be less than or equal to 45 Watts and efficiency above 90 is preferred. 

4. The latter is preferred, dividing a Single supply into positive and negative components. 

5. The application is for 240V 20kW. 

[AZIZ_HASSAN]

Hi,

Thank you for the details.

Since, the DC link voltage is low and I believe, the isolation voltage needed is not more than 1KV, the best suited topology for gate driver SMPS is Flyback converter. Generally, if we need high isolation voltage, we go with Push-Pull configuration. 

PFA of flyback converter application note which will give  you complete details to design the supply. Major advantage of this CoolSet IC is the primary switch is integrated in the IC it self and hence eliminating the need of external switch. As per your requirement, we can help you to modify the design for you. Suppose if you need the input voltage to be coming from DC link voltage or some other low voltage DC source, you need to remove the input ac-dc section and feed the required dc directly. Secondly, if you don't want the feedback, you can remove the same and make it work in open loop system.

https://www.infineon.com/dgdl/AN-EVALSF2-ICE2B765P2-3.pdf?fileId=db3a304412b407950112b418b9a1268c&da...

In addition to the information, may I know why you need 45 Watts as output power.

I hope this will solve your purpose.

BR,

AZIZ HASSAN

[AZIZ_HASSAN · Accepted solution]

Hi,

May I know an update on the topic.

BR,

AZIZ HASSAN

[asrikrishnagovi]

Hello, no query as of now. Thanks for your informative solutions! Regards