bluerobotics / blueesc Goto Github PK

Hi Rusty:

I took a peek at the design you used for the Rev1 version of the BlueESC. The driver configuration you are using seems to be for a P-channel high-side switch, yet the schematic shows a N-channel high-side switch. I can't see how you're going to get a fully-enhanced high-side transistor with this configuration, leading to poor efficiency and overheating of the high-side transistor.

-Walt Holm

Hello. I was looking for an ingenious design which would me allow to ditch the gate drivers I use, hence looked at the schematic in https://github.com/bluerobotics/BlueESC/raw/master/BlueESC/BlueESC.pdf
But quickly realized that it will not perform on a par with the gate drivers (at least for the high side NMOSFETs).
The upper FETs are N-channel. They turn on with positive voltage on the gate relative to the source.
Watching the schematic in the https://github.com/bluerobotics/BlueESC/raw/master/BlueESC/BlueESC.pdf you can see that the upper FETs can get positive voltage on their gates from the high side of the capacitors via 100 Ω plus 2.2 kΩ resistors when the NPN transistors are OFF. This mean that the total resistance on this path is 2.3 kΩ, so the turn on RC constant is 10-20 times longer. E.t. instead of 100 nS, it goes at least to 1000 nS. This should lead to more heat generated by the upper FETs (if the charging pumps work as intended and supply higher than Vcc voltage to turn on the upper FETs). You should use either more sophisticated push-pull high side gate driver or use an IC gate driver (which of course will make the BOM with higher cost).

The manual doesn't explain what the red and blue LED's indicate on the integrated BlueESC. Also what does it mean when it beeps every few seconds?

I am able to read I2C data from the BlueESC but am unable to get prop spinning when writing I2C. Do you have any debug suggestions? Do you have to use PWM stop signal to activate motor, prior to being able to use I2C? I assume not? Do you have some I2C Python SBUS examples you could post to make sure I'm using your desired conventions? Thanks
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Add a weak pull down to the PWM line so that it doesn't have to be grounded for I2C to work properly.

Hi, sorry to open ticket for my question , actually I intend to made modular ESC in way that controller + gate driver is separated from Mosfets pcb , hence I could increase module ampere by adding parallel Mosfet in the Mosfets pcb, I really appreciated to have your advise or if you know open HW/SW sources let me know

The current sensor bandwidth is too high causing slow measurements to require a large software low-pass filter for accuracy. A hardware low pass should be added to resolve this.