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Diodes & Thyristors (Si/SiC) Forum Discussions

KUOWENYUNG
Level 3
50 sign-ins 10 replies posted 5 replies posted
Level 3

Hello Sir,

May I know how to select the C5/C6 by parameter IR&QC&CT? 

Does the IR, QC, CT parameter can effect switching performance? why? thanks!

 

G5_G6_COMPARE.png 

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1 Solution
AZIZ_HASSAN
Moderator
Moderator 100 sign-ins 50 solutions authored 10 likes received
Moderator

Hi,

Thank you for posting at Infineon community.

I would like to answer your query point wise.

1) C5 is 5th generation diode and C6 is 6th generation diode. Selection  of C5 or C6 is  based upon your application requirements. If you application needs more I^2*t , more half wave forward surge current, more dv/dt rugged solution, less loss and better cooling etc. , you can select C6 diode.

2) IR is reverse bias leakage current. If the current is lower, the thermal performance will be better. However, in C6, the packaging and thermal solutions are already good and can handle more loss for same C5 package and operating temperature (for same Tj= 135 C).

3) Qc along with Vf is a parameter for switching performance. The total capacitive charge * forward voltage drop is called as figure of merit(FOM) and should be small to reduce your switching losses.

For C5 , FOM= 34.5 and for C6, FOM= 26.875.

4) CT is the junction capacitance at reverse voltage . Generally this parameter is taken at nearly zero reverse voltage application and should be small. If it is small, then the charging and discharging could be faster resulting in faster switching speed. But due to less switching loss of C6(less FOM) even though the CT is high, you can achieve same switching speed as in C5. I would like to add one more point here which is different than fundamentals is , at max. reverse voltage application, C6 has less capacitance than C5.

I hope the understood the explanation. If you need any other help let me know.

BR, 

Aziz Hassan

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1 Reply
AZIZ_HASSAN
Moderator
Moderator 100 sign-ins 50 solutions authored 10 likes received
Moderator

Hi,

Thank you for posting at Infineon community.

I would like to answer your query point wise.

1) C5 is 5th generation diode and C6 is 6th generation diode. Selection  of C5 or C6 is  based upon your application requirements. If you application needs more I^2*t , more half wave forward surge current, more dv/dt rugged solution, less loss and better cooling etc. , you can select C6 diode.

2) IR is reverse bias leakage current. If the current is lower, the thermal performance will be better. However, in C6, the packaging and thermal solutions are already good and can handle more loss for same C5 package and operating temperature (for same Tj= 135 C).

3) Qc along with Vf is a parameter for switching performance. The total capacitive charge * forward voltage drop is called as figure of merit(FOM) and should be small to reduce your switching losses.

For C5 , FOM= 34.5 and for C6, FOM= 26.875.

4) CT is the junction capacitance at reverse voltage . Generally this parameter is taken at nearly zero reverse voltage application and should be small. If it is small, then the charging and discharging could be faster resulting in faster switching speed. But due to less switching loss of C6(less FOM) even though the CT is high, you can achieve same switching speed as in C5. I would like to add one more point here which is different than fundamentals is , at max. reverse voltage application, C6 has less capacitance than C5.

I hope the understood the explanation. If you need any other help let me know.

BR, 

Aziz Hassan

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