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MOSFET Switching Losses

Not applicable
Studying design documentation and official Infineon application notes I have encountered some problems. Particularly I am a bit puzzled with
[1] Graovac D., Purschel M., Kiep A. MOSFET Power Losses Calculation Using the Data-Sheet Parameters / Infineon: Application Note 2006-07 V1.1. – Infineon Technologies AG, 2006. – 23 p.
As far as I see there is a mismatch between input parameters for MOSFETs dynamic losses calculations and parameters given in datasheets.
According to Fig.6 on page 7 of [1] in hard switching mode the time tri is the interval where the drain current of turning-on MOSFET rises from near zero to load current, while tfu is the interval where the drain current falls during turn-off. These dynamic parameters are used for losses calculation, and as indicated on Fig.7 (and commented in the text on page 6) can be read from a device datasheet (as the worst-case values).
However, as I see in
[2] Huang A. Infineon OptiMOS Power MOSFET Datasheet Explanation / Infineon: Application Note 2012-03 V1.1. – Infineon Technologies AG, 2012. – 30 p.
they represent absolutely different values. According to Fig.31 of this document (page 29) tr is the voltage fall time during turn-on (90% to 10%) while tf is the voltage rise time durin turn-off (10% to 90%). The same definitions are given on page 13 (Table 20) in
[3] MOSFET CoolMOS E6 IPx65R280E6 / Infineon. – 2010. – 19 p.
In my opinion, these two parameters given in datasheets are not relevant to whose indicated in calculation losses strategy.
May be it is because in IGBT datasheets tris defined as the collector current rise time during turn-on and tf is defined as the collector current fall time during turn-off. For example, IGBT case is shown on page 15 in
[4] Infineon IKD06N60RF datasheet. – 2014-03-12, Rev. 2.4. – 16 p.
I come to the conclusion, that the calculation strategy in [1] does not distinguish differences between dynamic characteristics, given in MOSFET datasheets, and dynamic characteristics, given in IGBT datasheets.
Could you, please, explain whether I am right or not and why.
Also, I would be grateful if you can provide other documentation for switching losses calculation for Infineon MOSFETs.
All the documents [1-4] are attached in this letter.
1 Solution
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Re: MOSFET Switching Losses

Employee
Employee
Hello,

Thanks a lot for your interest in Infineon products.

1. To your point of mismatch between the definition of rise- and fall-time in the app note and in the data sheet:

There is no mismatch here, since the app note “MOSFET Power Losses Calculation Using the Data-Sheet Parameters” is only for Infineon automotive power products and the data sheets you mentioned are not automotive products.
Here please find the automotive MOSFET products: http://www.infineon.com/cms/en/product/power/mosfet/automotive-mosfet/channel.html?channel=ff8080811...

2. To the point of your conclusion:

The principle of the power losses calculation for MOSFETs and IGBTs should be similar. The difference is that for IGBTs we have always energy parameters given in the data sheet. Therefore the calculation is carried out with the energy parameters. We have also an app note called “IGBT Power Losses Calculation Using the Data-Sheet Parameters”, which is attached. Please be aware that this app note is also only for Infineon automotive power products.

As I know, there is no other document for switching losses calculation of Infineon MOSFETs published till now.

BR,
Jianan
2 Replies
Attachments are accessible only for community members.

Re: MOSFET Switching Losses

Employee
Employee
Hello,

Thanks a lot for your interest in Infineon products.

1. To your point of mismatch between the definition of rise- and fall-time in the app note and in the data sheet:

There is no mismatch here, since the app note “MOSFET Power Losses Calculation Using the Data-Sheet Parameters” is only for Infineon automotive power products and the data sheets you mentioned are not automotive products.
Here please find the automotive MOSFET products: http://www.infineon.com/cms/en/product/power/mosfet/automotive-mosfet/channel.html?channel=ff8080811...

2. To the point of your conclusion:

The principle of the power losses calculation for MOSFETs and IGBTs should be similar. The difference is that for IGBTs we have always energy parameters given in the data sheet. Therefore the calculation is carried out with the energy parameters. We have also an app note called “IGBT Power Losses Calculation Using the Data-Sheet Parameters”, which is attached. Please be aware that this app note is also only for Infineon automotive power products.

As I know, there is no other document for switching losses calculation of Infineon MOSFETs published till now.

BR,
Jianan
Attachments are accessible only for community members.

Problem between datasheet explanation and application note

Not applicable
Jianan Shen wrote:
Hello,

Thanks a lot for your interest in Infineon products.

1. To your point of mismatch between the definition of rise- and fall-time in the app note and in the data sheet:

There is no mismatch here, since the app note “MOSFET Power Losses Calculation Using the Data-Sheet Parameters” is only for Infineon automotive power products and the data sheets you mentioned are not automotive products.
Here please find the automotive MOSFET products: http://www.infineon.com/cms/en/product/power/mosfet/automotive-mosfet/channel.html?channel=ff8080811...

2. To the point of your conclusion:

The principle of the power losses calculation for MOSFETs and IGBTs should be similar. The difference is that for IGBTs we have always energy parameters given in the data sheet. Therefore the calculation is carried out with the energy parameters. We have also an app note called “IGBT Power Losses Calculation Using the Data-Sheet Parameters”, which is attached. Please be aware that this app note is also only for Infineon automotive power products.

As I know, there is no other document for switching losses calculation of Infineon MOSFETs published till now.

BR,
Jianan

Hi,

"MOSFET Power Losses Calculation Using the DataSheet Parameters" explains how losses could be calculated for automotive application Mosfets,
But the problem is that, I found the "Automotive Mosfet Data Sheet explanations", Here datesheet parameters are explained. For rise time and fall time of mosfet, the explanations are exactly like that;

"The turn-on time, ton, of a MOSFET is the sum of the turn-on delay time td(on) and the rise time tr.
td(on) is measured between the 10% value of the gate-source voltage and the 90% value of the drain-source voltage.
The rise time tr is measured between the 90% value and the 10% value of the drain-source voltage.
The turn-off time, toff, of a MOSFET is the sum of the turn-off delay time td(off) and the fall time tf.
td(off) is measured between the 90% value of the gate-source voltage and the 10% value of the drain-source voltage.
The fall time tf is measured between the 10% value and the 90% value of the drain-source voltage."

That means, rise time and fall time of automotive application Mosfet are also defined with respect to Voltage, not Current. But interestingly, "MOSFET Power Losses Calculation Using the DataSheet Parameters" gives calculation based on Current.

If "datasheet explanation" describe values with respect to voltage, how "power losses calculation" describe it with respect to current
?????

thanks