Author Topic: Combination of TVS Diode + Zener  (Read 747 times)

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Offline Red_MicroTopic starter

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Combination of TVS Diode + Zener
« on: May 06, 2020, 01:25:20 am »
Looking into this Reference Design they use a combination of TVS + Zener diode (D6 & D7 in the schematic) for clamping the voltage at the FET's gate. How does this exactly work? Doesn't the differences between the zener and TVS matter in this case?
 

Offline Jay_Diddy_B

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Re: Combination of TVS Diode + Zener
« Reply #1 on: May 06, 2020, 01:53:20 am »
Red_Micro and the group,

That configuration is this:




The MOSFET is in series with the MOSFET inside the IC U2. IT is called the Cascode configuration.

The 500V Zener string limits the voltage on U2

The 12V Zener limits the Vgs on the MOSFET.


It is being done here to raise the maximum operating voltage of U2.

Regards,
Jay_Diddy_B
 

Offline Vovk_Z

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Re: Combination of TVS Diode + Zener
« Reply #2 on: May 06, 2020, 11:30:57 pm »
Why not Zener? It can be because it is much easier to find 200V & 300V TVS then 200V or 300V Zener.
« Last Edit: May 06, 2020, 11:32:31 pm by Vovk_Z »
 


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