Inn2023K stop working primary side don´t switch, no voltage on Bypass Pin

Hi,

The information you share is not enough for me to understand how the part get damaged. Can you share more details such as what testing was done prior to part getting damaged such as input voltage, load etc...? Maybe, it would be better if you could share also your schematic, layout, transformer design, required input range, and output power.

Regards,

Jedidiah

Normally the electronic should work on max. 250V AC. The peak load is around 6W. The minimal input voltage should be around 170V AC

If I understand correctly the INN2023 was broken during reconnect to mains. To get an reset on secondary part the electronic was disconnected from mains and the moment it was reconnected it broke.

The electronic don´t get an any high voltage test or something like this.

Hi,

You better create a correct schematic first before you power-up your power supply. We have lots of reference material here in our website.

You can download the datasheet in below link for your to understand the required flyback schematic.

https://www.power.com/products/innoswitch/innoswitch-ch/inn2023k#product_resources

Also, we have an online tool that will help generate design for you. You may go to this link:

https://piexpertonline.power.com/

All of this will help you create a correct schematic/power supply design.

Regards,

Jedidiah

Because I have a problem on the primary side i only share the primary side. 

Pi expert online is not helpful, because it doesn´t support the Inn2032k.

Hi,

Yes, you're primary side schematic has a lot of problem as it is not correct to start with....

Pages 8-15 of the datasheet can guide you in creating flyback converter.

https://www.power.com/products/innoswitch/innoswitch-ch/inn2023k#product_resources

Regards,

Jedidiah

Hi,

yes my design looks different from the schematic inside the current datasheet. The design is near to the schematic from the Rev. E03/16 Figure 17 (PI-7686-071715). 

So please give me the detail about the wrong part. 

Hi,

Can you give me the link where you see Rev. E03/16 Figure 17 (PI-7686-071715)?

Regarding your schematic, below are the things you need to correct in your primary schematic:

1) You should correct your primary snubber in RCD configuration or best is R2CD configuration.

--> Add parallel capacitor with R53, add series resistor with V10.

2) You BPP is being charge from high voltage input side.

--> Remove your components connected to C4. (C18, R26, V6, V9).

All of this is already in Page1 of the datasheet

https://www.power.com/sites/default/files/documents/innoswitch-ch_family_datasheet.pdf

3) If you want your BPP not to be charge from Drain tap during normal opertation, you may add bias circuitry.

Figure 14 Page 8 is sample of complete schematic of a working power supply flyback converter.

https://www.power.com/sites/default/files/documents/innoswitch-ch_family_datasheet.pdf

NOTE: I only comment on primary side since you did not share your secondary side schematic. Also, I don't know what transformer design your are currently using.

In case you need more details regarding flyback converter, there should be available free resources online that you can download to gain knowledge in creating flyback converter.

I hope this helps....

Regards,

Jedidiah

Hi M. Harms,

looking at the schematic for your primary, it seems like you are trying to power the BPP pin from the snubber voltage.

The voltage variation across C18 will depend on many parameters, including transformer leakage, operating frequency, and primary winding peak current. I can't compute any estimates without knowing the details of the transformer and the rest of your design, but you might be getting large voltage spikes on C18, which result in large spikes of current going through diode V6 into the BPP pin. It is possible that these excessive currents damage the INN2023K device. Even identical designs will have significant variations in the leakage, so the issue could be more severe in some boards than others.

This is my educated guess based on the info you have provided and is consistent with the symptoms that you described.

To avoid these types of issues, PI recommends either not connecting the BPP pin capacitor and letting it charge from the internal regulator or using a bias winding. Jedidah linked you the datasheet that shows an example of how to utilize a bias winding.

If my guess is correct then you could possibly get a bandaid fix by attaching an external carefully chosen zener to the BPP pin to take the excess current. But, this will increase both your component count and the losses in the design. Even if it works, I think it would be an inferior solution to removing V6 and V9 and disconnecting C4 from the primary snubber.

Hi,

here the old Version of the Datasheet.