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Mac_Kurosawa
Level 4
Level 4
Distributor - Macnica (Japan)
10 solutions authored 5 solutions authored 10 replies posted
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Anshika_G
Moderator
Moderator
Moderator
First question asked 50 likes received 250 replies posted

Hello @Mac_Kurosawa , 

I would need more details like:
1. Are you driving the load with PWM? If PWM, what's the frequency?
2, Inrush current? Peak current?

The most important thing to take of induction load energy when it is turned off as the load can generate a huge negative voltage which could damage the driving circuit. 

Switching off, the PROFET™may see high switching losses (at least, EOFF = 0.5 x (VBAT+0.7 V) x ILOAD x tOFF). The
switching losses may cause dynamic temperature increases of more than 80°C, triggering the dynamic
temperature limitation of the device. It is recommended to keep the temperature increase significantly below
80°C and not to switch off during normal startup / inrush current.

Please refer to the following appnote for PROFET+24V devices, Page 28, Section 5 Inductive loads. Please note here in the document, motor is considered as induction as example. 

Kindly use Infineon Smart Power Switches Easy APE Pro Tool to support system partitioning and the calculation of most important electrical parameter. 

Thanks, 
Anshika


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3 Replies
Anshika_G
Moderator
Moderator
Moderator
First question asked 50 likes received 250 replies posted

Hello @Mac_Kurosawa , 

I would need more details like:
1. Are you driving the load with PWM? If PWM, what's the frequency?
2, Inrush current? Peak current?

The most important thing to take of induction load energy when it is turned off as the load can generate a huge negative voltage which could damage the driving circuit. 

Switching off, the PROFET™may see high switching losses (at least, EOFF = 0.5 x (VBAT+0.7 V) x ILOAD x tOFF). The
switching losses may cause dynamic temperature increases of more than 80°C, triggering the dynamic
temperature limitation of the device. It is recommended to keep the temperature increase significantly below
80°C and not to switch off during normal startup / inrush current.

Please refer to the following appnote for PROFET+24V devices, Page 28, Section 5 Inductive loads. Please note here in the document, motor is considered as induction as example. 

Kindly use Infineon Smart Power Switches Easy APE Pro Tool to support system partitioning and the calculation of most important electrical parameter. 

Thanks, 
Anshika


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Mac_Kurosawa
Level 4
Level 4
Distributor - Macnica (Japan)
10 solutions authored 5 solutions authored 10 replies posted

Hello Anshika

Thank you for your reply.
I'll check more details.

I have a question about the following equation.

EOFF = 0.5 x (VBAT+0.7 V) x ILOAD x tOFF)

The equation appears to differ in form from Equation (4) on page 29 of the reference material. How can it be derived to match the equation above?"

Best regards,
Shun

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Hello @Mac_Kurosawa , 

As I have mentioned in my previous reply, "Switching off, the PROFET™may see high switching losses (at least, EOFF = 0.5 x (VBAT+0.7 V) x ILOAD x tOFF)"
Please note that this is general/ideal formula for calculating switching losses for MOSFET devices. 

The formula given in page 29 is exclusively when switching a inductive load. 

Best Regards,
Anshika

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