Arduino BLDC TLE9879 shield && Voltage


New to the BLDC Shield with TLE9879QXA40 for Arduino.

The Infineon page shows the shield power supply is accepting up to 28V.

However the User Manual clearly mentions that the power supply is 12V.
The board, as well, is clearly labelled “12V”.

Couple questions if you please

  1. Can the board accommodate higher V, like 20V (@ ~5A), unlike what’s being said?

  2. Are there any drawbacks / demerits using 20V instead of 12V? (what does change actually?)

Thank you and regards

Hello Tagadada,

Yes, I can see the problem.

The board is clearly marked as 12 VDC while the description page and data sheet as marked as 28 VDC max.


With regards to your questions:

  1. Based on this 2 out of 3 information, I believe you are correct to operate the board at higher voltages.

  2. As for the advantages of higher voltage consider the power of the motor. For any given power, the high voltage system will require less current. When we consider 12 VDC vs 20 VDC, this may have a small efficiency advantage as there will be less I^2R losses. From a practical perspective, there is likely more advantage to matching the motor to the load.

Perhaps others can add additional information about selecting the components for your system.

Best Wishes,



Hi Tagadada,

I can think of one or two possible reasons why they might show 12V on the board. The TLE9879 uses internal linear regulators to convert the input voltage down to I/O voltage (5V) and core voltage (1.5V) rather than using external regulators to perform this function. Unlike switching regulators, linear regulators essentially waste all of the excess voltage during the voltage conversion process. This means that it has to dissipate quite a bit of internal heat in this process, and the higher the input voltage, the more heat it must dissipate.

You’ll notice that the TLE9879 has an exposed die pad on the underside of the package to help dissipate this heat. The effectiveness of this heat dissipation is directly related to the size of the copper area directly adjacent to this pad and the amount of airflow present to evacuate this heat from the board.


Since their example uses 12V, it may be that they only feel confident that the board can handle this high a voltage and still easily dissipate the generated internal heat – especially when stacking 4 boards together, as they show in their example. They are likely being conservative, so as not to have demo board failures.

One other possibility for going with 12V is that the example software and/or some of the hardware (current sense resistor, for example) might have been written/selected with the assumption that it would be operating in a 12V environment. Exceeding that could possibly be outside of the design parameters of this particular board. Page 5 of the board user’s manual lends some credence to this possibility: