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SMPS

Posted by: akanksha upadhyay on 03/18/2021

Hello,
I am designing a flyback topology SMPS of 10 W ,5V output and input range is 90 V AC ~ 510 V AC ,precisely speaking 440V AC .PWM controller which I am using is innoswitch3-ep (INN3692C). I am unable to find a suitable transformer for the same.

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Submitted by akanksha upadhyay on 03/18/2021

smps

Submitted by PI-Spark on 03/30/2021

Hi akanksha,
Thank you for using Power Integrations products.
Which exact problem do you encounter when selecting a suitable transformer?
You can use PI Expert Online to automate calculations for your InnoSwitch3-EP design, particularly the transformer section.
https://piexpertonline.power.com/site/login
You may also check our DER-745: 90-420VAC input, 10W dual-output design using INN3692C.
https://ac-dc.power.com/design-support/reference-designs/design-examples/der-745-10watt-dual-output-power-supply-using-innoswitch3-ep-900v/

Regards,
PI-Spark

Submitted by akanksha upadhyay on 03/31/2021

Hello,
Thanks for the reply ,as you said i used the piexpertonline.power.com but i am facing little problem My input voltage range is 90-510 V and my continuous voltage is 440 V but the design platform can take max of 300 AC input voltage (inspite of selecting user defined option ) so if i select it there would be quite a difference ,so please guide me on this.

With Regard
Akanksha

Submitted by PI-Spark on 03/31/2021

Hi Akanksha,
Can you download your PI Xls design and upload the file here, I'll check it and guide you from there.
Regards,
PI-Spark

Submitted by akanksha upadhyay on 04/08/2021

Hi Spark,
Once again thanks for the reply ,i am attaching a pdf file with this please have a look. Basically i am having trouble with the RV_BIAS_ENABLED parameter if i am selecting it as auto i am getting a warning over OVERVOLTAGE_LINE parameter ,what is actually the meaning of RV_BIAS_ENABLED , what effect will i have if i don't choose this option and also as i am designing SMPS for the first time it would be great if you can suggest the transformer.

with regards,
Akanksha

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Submitted by PI-Spark on 04/12/2021

Hi Akanksha,
The InnoSwitch3 power supply input undervoltage and overvoltage protection thresholds are determined by the current into V-pin (see IUV and IOV parameters in device datasheet).
Typical implementation for Line OV/UV protection is two resistors from DC bulk capacitor voltage to V-pin, but for your application (wide input voltage up to 440VAC) a circuit modification for V-pin is needed to extend the OV threshold value.
RV_BIAS_ENABLED refers to this circuit modification wherein current is injected from BPP into the V-pin through a diode.
You may check Application Note 72 (https://ac-dc.power.com/sites/default/files/product_document/application_note/an-72_innoswitch3_family_design_guide.pdf) or the attached image for simple schematic.
In this circuit, R2 is the required resistance between the diode and V-pin (shown in the spreadsheet as RV_BIAS) and R1 is the resistance from V-pin (RLS in the spreadsheet).

For the transformer, if the size allows, you may use RM6 or EE22 core.
PI Expert automatically calculates the the turns ratio and primary inductance based on your design parameters (by default it shows results for flux density < 3800Gauss).
There is also a Transformer construction tab in the spreadsheet to guide you.
You may also browse Design Example Reports (DER) in our website, these documents have detailed transformer construction for their corresponding designs.

Regards,
PI-Spark

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Submitted by akanksha upadhyay on 04/27/2021

In reply to by PI-Spark

HI Spark,

Thanks for the reply it really  guided me a lot .I would like to know that  how can i get the spice model of INNOSWITCH -3ep ic .

 

Regards,

 Akanksha