wasserwiesel
Well-known member
Hello there,
I use the Teensy 4.0 to control a brushed motor (8.5x20) with a PWM signal (20khz).
I created a PCB for this. It works, but the motor and the mosfet get very hot quickly. I use a 1S Lipo Battery.
Even at 1A it gets hot. If, on the other hand, I connect the motor directly to a voltage supply, it only gets slightly warm.
So it must have something to do with the circuit. The Mosfet should not get warm with such a small load.
The motor driver is actually designed for 4.5V, not 3.7V. Nevertheless, I still use it because you can see in the data sheet that it
should output around 100mA even at such a low voltage. This is sufficient as a gate current for the Mosfet at that frequency. Even 50mA should be fine.
I've already tried to measure the current at the output of the driver, but my measuring device seems to be broken, at least the fuse^^
Could the mosfet get warm because the gate current is too low?
I don't know what to do at the moment...
Anyone have an idea?
Driver: https://datasheet.lcsc.com/lcsc/2005070932_Microchip-Tech-MIC4416YM4-TR_C515508.pdf
Mosfet: https://datasheet.lcsc.com/lcsc/1806130217_UTC-Unisonic-Tech-UT4404G-SO8-R_C84908.pdf
This is the schematic:
I use the Teensy 4.0 to control a brushed motor (8.5x20) with a PWM signal (20khz).
I created a PCB for this. It works, but the motor and the mosfet get very hot quickly. I use a 1S Lipo Battery.
Even at 1A it gets hot. If, on the other hand, I connect the motor directly to a voltage supply, it only gets slightly warm.
So it must have something to do with the circuit. The Mosfet should not get warm with such a small load.
The motor driver is actually designed for 4.5V, not 3.7V. Nevertheless, I still use it because you can see in the data sheet that it
should output around 100mA even at such a low voltage. This is sufficient as a gate current for the Mosfet at that frequency. Even 50mA should be fine.
I've already tried to measure the current at the output of the driver, but my measuring device seems to be broken, at least the fuse^^
Could the mosfet get warm because the gate current is too low?
I don't know what to do at the moment...
Anyone have an idea?
Driver: https://datasheet.lcsc.com/lcsc/2005070932_Microchip-Tech-MIC4416YM4-TR_C515508.pdf
Mosfet: https://datasheet.lcsc.com/lcsc/1806130217_UTC-Unisonic-Tech-UT4404G-SO8-R_C84908.pdf
This is the schematic: