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VijayBhaskar
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We are using a IGBT Driver IC (IR21271STRPBF) to drive two IGBTs ( STGWA50M65DF2) fom MCU using common PWM. The Gate PWM Voltage is 15V. which inturn controls the Heater connected to the Source at 48V. Here we are observing the drop of 19V to 20V across Emitter and Collector which makes the design inefficient and increasing the power consumption. (5A Heater Current; 20V X5A = 100W power dissipation across IGBT). So we need a solution to replace the existing IGBT with a suitable MOSFET with lesser voltage drop to reduce the power loss.

Driver IC:
https://www.infineon.com/dgdl/Infineon-ir2127-DS-v01_00-EN.pdf?fileId=5546d462533600a4015355c8688616...

IGBT:
https://www.st.com/resource/en/datasheet/stgwa50m65df2.pdf

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1 Solution

Hi Vijaya Bhaskar:

Vth is MOSFET from "OFF" to "ON" voltage, it is not G-S limit.

The MOSFET G-S max rating  is:

_0-1687148058762.png

So you can use 15V to gate drive.

View solution in original post

11 Replies
AZIZ_HASSAN
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5 likes given 250 sign-ins 100 solutions authored

Hello Vijay,

The IGBT in any case do not  give so much drop. Please share your schematic and waveform to analyze it deeply.

Thanks and regards,

AZIZ

 

VijayBhaskar
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Hi Aziz,

 

Please find the schematic image attached herein.

 

We do not have the waveforms, but we have measured the voltage across the circuit, let us know if you need more info about the measured values.

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喜马拉雅之雪
Employee

Hi VijayBhaskar:

As PWM, load current and voltage is not only DC. Most AC run the loop.

For example: PWM is 1Hz 50%. The IGBT is first 0.5 second  is “ON” and next 0.5 second is "OFF".

In "ON" time, as IGBT is short, VCE is about 1.5V. In "OFF" time, IGBT VCE is about 48V, if your power DC is 48V.

So the VCE is about 24.8V in 50% PWM function by DC voltage meter display.

As "ON" time, IGBT power loss is VCE*ICE(set ICE=10A)=15W, "OFF" time, the loss is VCE*ICE=0W

So IGBT power loss is about 7.5W for your reference.

For load: If on PWM=50% function, DC current meter diaplay is 5A, than:

The load current (on "ON" time) is 5A/50%=10A

The load power is (48V-VCE)*10A*50%=233W

VijayBhaskar
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Hi, thank you for your response.

Can you please suggest me how to reduce the Power Loss when the IGBT is "ON" ?

Does replacing the IGBT with MOSFET resolves this issue ?

Thank You 

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For 48V application, 100V or 150V MOSFET is best for efficiency.

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VijayBhaskar
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Can you please suggest a MOSFET from Infineon or any other manufacturer which suits our requirement of "Gate PWM Voltage is 15V. which inturn controls the Heater connected to the Source at 48V." So that I can quickly test the functionality and implement in my design.

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What is your load? How much their resistance(ohm) ?

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VijayBhaskar
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Hi our Load is Resistive Heater of 240W (48V x 5A). Resistance of the Load is between 13.5 Ohms to 14.5 Ohms.

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VijayBhaskar
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Hi Infineon Team, 

Thank you for your response. 

As in our Case, the existing Gate PWM Voltage is 15V. which inturn controls the Heater connected to the Source at 48V. But in the IRFB4110 MOSFET Datasheet, I see the Gate Threshold Voltage (VGSth) is Max. 4V. Will this Part withstand 15V Gate Drive Voltage? I am attaching the Snapshot of Schematic for your reference.

 

 

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Hi Vijaya Bhaskar:

Vth is MOSFET from "OFF" to "ON" voltage, it is not G-S limit.

The MOSFET G-S max rating  is:

_0-1687148058762.png

So you can use 15V to gate drive.