SWITCHING FREQUENCY

[MS_19060803]

Hi all,

Figure 1 is shown in the IKW40N120H3 data sheet.

Could you please disclose the same graph for IHW40N120R5 and IKW40N120CS6?
The frequency range is 1 to 1000kHZ.

If you could not, could you please tell me the reason？

Best regards,

MS

[Guru_Prasad]

Hello @MS_19060803 ,

Thanks for posting your question in the Infineon community.

Please refer the answer which was posted by Klaus

Thanks

Guru

[MS_19060803]

Hi,

Thank you for the prompt response.

You said that the IHW40N120R5 and IKW40N120CS6 can operate above the rated frequency.

Which is correct, A or B?

A:The current value will be at the red points in the graph.
B:The current value will decrease extremely below the red points.

Best regards,

MS

[_Klaus · Accepted solution]

Hi everyone, 

let me please add a few comments here:

What does the graph show?

The graphs mentioned above do not indicate any kind of SOA. This means that you are free to exceed the 60A even at 140kHz, as long as you can manage it thermally (Tvj<=175°C). This might imply low duty cycles and powerful cooling.

Instead, the graph indicates a maximum current that the IGBT can conduct and switch until it reaches 175°C... at very specific conditions: Tc=100°C whatever loss is generated,  duty cycle 50%, bus voltage 600V, Rg=12OHm, Vge=15/0V.

Why don't we have it in recent data sheets anymore?

You can only draw such a graph for very specific conditions. However, the conditions differ from application to application. To give some examples:

• cooling arrangements contain several switches on a specific heat sink insulated with specific foils --> the condition Tc=100°C does not work anymore
• Vge and Rg are optimized for overshoots and EMC --> the condition Vge=15/0V and  Rg=12Ohm does not work anymore
• ...

What could be a way to compare different devices?

We offer online simulation tools where you can calculate losses and temperatures for different circuits under different conditions. The advantage here is that you are free to select devices and conditions and make them as close to your application as possible.

Alternatively, you could also calculate such stuff using an offline simulator and the models we provide on our web page. Some people also use simple Excel spreadsheets to calculate such things as shown in that blog post.

Hope that helps!
Best regards,
Klaus

PS: Please not that while the IKW40N120H3 and the IKW40N120CS6 are somewhat exchangeable, the anti-parallel diode of the IHW40N120R5 is not made for hard-commutation.