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MOSFET (Si/SiC) Forum Discussions

Daniel2
Level 1
Level 1
5 replies posted 5 likes given First like given

Hello,

in older designs I'm using the IR2184S half-bridge driver with two IRF7831 n-channel MOSFETs for the power stage. I'm now about to update and shrink our design.

The product page for IRF7831 states that this MOSFET is not recommended for new designs. Could you please provide a drop-in replacement that is readily available? For example, what about the IRF7832 or IRF7862?

Further, the IR2184S half-bridge driver requires a VCC ("Low side and logic fixed supply voltage") from 10 .. 20 V. The main voltage in my new design is 24 V. To avoid the need for a dedicated voltage regulator, I'm looking for a replacement driver that can be operated either with 24 V directly or with 5V as that is available in this design already.

I appreciate your help.

Thank you.

Best regards,
Daniel

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12 Replies
Dipti_Kiran
Moderator
Moderator
Moderator
100 sign-ins 5 solutions authored 10 replies posted

Hi Daniel,

The replacement of IRF7831 n-channel MOSFETs in same package is listed below:

Dipti_Kiran_0-1672860064074.png

Note: It is always recommended to choose the products that are “active and preferred”.

You can choose IRF8788 which have better RDS(on) in same package.

Further to your request, there is no exact replacement for IR2184S half-bridge gate driver. May I know the below mentioned details so that we can suggest alternate half-bridge gate driver which can be best possible fit for your design based on your requirement?

  1. Application in which gate driver is being used
  2. Peak gate current
  3. Gate voltage
  4. Switching frequency

Regards,

Dipti

 

Hi @Dipti_Kiran ,

Thank you for your reply. I really appreciate your suggestions. I wonder why the IRF7832 (which I had  mentioned) is not included in your list of replacement devices?

Regarding your questions:

1. The driver will be used to drive the IRF7831-replacement, e.g. IRF7862 (which has a better availability than the IRF8788), in a synchronous buck topology. The load is resistive. While the IR2184S supports high side drain voltage up to 600 V, our application does not need this. Our "bus voltage" is only 24 V. Including a safety margin VB to GND could be specified as 50 V.

2. I don't know. How do I calculate this?  I expect a max. source current of about 3 A.

3. How can I find out? Datasheet states: Rds(on) is 3.3mOhm at Vgs = 10V. Drain voltage is 24 V in my application. As mentioned earlier, the driver should operate from 24 V or 5 V.

4. Switching frequency is about 50 - 65 kHz.

Hope that helps.

Best regards,
Daniel

 

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Dipti_Kiran
Moderator
Moderator
Moderator
100 sign-ins 5 solutions authored 10 replies posted

Hi Daniel,

Regarding your queries:

I wonder why the IRF7832 (which I had mentioned) is not included in your list of replacement devices?

--->Generally, we recommend devices with same or higher ratings than the component under consideration. IRF7832 is not included in the list of replacement devices as it has lower current ratings i.e 20A than IRF7831 (Id=21A @ Tj-25degC). As per your operating condition and the margin, if ID=20A is suitable for your application, you can still choose IRF7832.

Further, for bus voltage of 24V, 30V MOSFET will have a narrow margin. It would be preferable to use 40V device. Under 40V, 18A is the max rating available with same package i.e IRF7842. Under 40V, 20A current rating, IPG20N4S4-12, IPG20N04S4L-18A, IPG20N04S4L-07A, IPG20N04S4L-07 are available devices with different package.

There is no gate driver that can be operated directly with 24V. However, IR2302S and IRS2302S can be operated directly with 5V but the source and sink current of both gate-drivers is <1A which will not meet your requirement. We need to enhance the current and this could be achieved by connecting an external booster circuit as shown below:

Dipti_Kiran_0-1673958755469.png

Note: The diagram shown above is only an example.

MOSFETs in the Booster circuit can also be replaced with BJT totempole. Kindly note, our assumption is that 5V is derived from a separate regulator and not from the output of the buck converter itself.

You can also go through the application notes for more details:
https://www.infineon.com/dgdl/Infineon-External_booster_for_Driver_IC-ApplicationNotes-v01_06-EN.pdf...

You can also search different gate driver as per your application needs from the link below:
https://www.infineon.com/cms/en/product/power/gate-driver-ics/#!products

Regards,

Dipti

 

Dear Dipti,

I appreciate your detailed response. 

Regarding replacement MOSFET devices, I understand that I should preferably use a device with Vds = 40 V. From your suggestions, my favorite would be the IRF7842. It has a SOIC-8 package and thus it would be a drop-in replacement, however, it seems unavailable at the usual distributors (e.g. Mouser will restock this device in 2024). 

Regarding gate drivers operated from 5V supply, from you explanation I understand that they usually provide lower source/sink currents compared to drivers with higher Vcc. I guess I should read this application note in order to better identify the gate driving capability that my design requires. Maybe a lower gate drive current would suffice.

Thank you.

Best regards,
Daniel

 

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喜马拉雅之雪
Employee

Hi Daniel:

Thanks for your request.

For the smart design, I thinks about low voltage IPM is better with your application. 40V 80A half bridge MOSFET and drive had inside in low size package.

This is the link of the datasheet and reference informance with you:

https://www.infineon.com/dgdl/Infineon-IRSM005-800MH-DS-v01_00-EN.pdf?fileId=5546d462533600a40153567...

Thanks

 

Dear @喜马拉雅之雪 ,

Thank you for your suggestion. That seems to be a very interesting and highly integrated device.

The only "drawback" (at least from my point of view) is that it requires separate drive input signals for the high and low side FET. Thusly, it does not provide a shoot-through protection.

Using this device, it is my responsibility to generate the two input signals from a single PWM signal while providing proper dead-times between switching to prevent shoot-through. Further, this "dead time generator" would consume additional real-estate on the board. That counteracts the goal of using a highly integrated device to save space on the board.

I'd rather use a device that is more "user-friendly" with regards to input signal.

Is there a highly-integrated device that can be driven with a single PWM input signal?

Thanks and best regards,
Daniel

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Hi Daniel:

Thanks for your comments. For "cross-conduction prevention logic" function, the IPM set a "IC Delay matching, HS and LS turnon/off " with it for meeting high frequency switching for remove body diode power loss. 

This is type circuit of single input change to twin output:

_0-1674036234697.png

 

Hi 喜马拉雅之雪 : 

Thank you for the schematic of a "cross-conduction prevention logic" (or "dead-time generator" as I called it).

Where did you pull this circuit from? I could not find it in the datasheet. Is it from an application note? Can you share a link, please?

Thanks.
Best regards,
Daniel

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Hi Daniel:

This is from 200W Class-D AMP application. The drive IC is IRS2011S.

This is classis design and most engineer had use it.

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For your request, we have 2 solution:

1) First idea is IPM. The solution like you see.

2) Use second source

For IRF7831, I had check sample with you. I find:

_0-1674038062418.png

You can order it.

Dear @喜马拉雅之雪 ,

regarding the picture that you sent, the  IQE013N04LM6CGSC is a superior device.  It supports Vds = 40 V and Id = 205 A. 

The max source current that I expect is 3 A  😁

 

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For new MOSFET:

1) You can order it. This is 3.7mR vs 1.5mR.

2)As different Rja, so their ID is very different.

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