This is the best cheapest DC motor speed controller circuit that you can find on internet.

In the past i tried wit NE555 and other circuits but the results were every time in shorted mosfet`s 😀 and not stoppable GO KART (not very good thing when you do not have a big red kill switch).

In in the following i will  present my DC Motor speed controller capable of adjusting speed (PWM)  form 0 – 100% and the frequency form  ~ 400Hz to 3kHz, based on LM339 comparator.

The power supply is from 14-30volts,  expandable to practical any value with little modification.

From R15 VR 10k you can adjust the speed from 0 -100%

From R14 VR 100k you can adjust the frequency.

If the jumper JP1 is shorted you can adjust the PWM frequency from 400Hz  to 3kHz. If jumper is open Freq is fixed at 100Hz.

The circuit is designed in Eagle cad 6.2



You can use almost any Channel N mosfet`s you want. The fets will be mounted on a radiator if the current is  higher than 2-5 amp.

It is possible to increase the voltage supply to any value if you separate the power to the logic circuit from power to the load and mosfet`s

This is my second prototype of dc motor controller


Depending on Rds ON value of the mosfet`s you will need a smaller or bigger radiator.

The wires will be at least 12 AWG for a 30 -35  amp load.

For any questions you can  ask me any time via my e-mail found on about menu.

Success with the circuit.

This is the real life testing of the circuit.




High quality improved PWM controller based on MC33035 IC.

Schematic :





Eagle 6.1 design.



I used as mosfet driver the TC4452 IC with is capable of 12Amp output.

I used this schematic in conjunction with power stage formed by 10 mosfets in parralel with all gate connected via 10pcs  20 ohm resistor to the output of the IC driver.

For current sense circuit i used allegro sensor ACS758

50-200A current sensor IC

The Allegro CA and CB package current sensor ICs are fully integrated current sensor solutions. They contain the primary conductor, concentrating ferromagnetic core and the analog output Hall-effect linear in a single IC package. The conductor resistance is a typical of 100 µΩ for ultra low power loss when sensing current up to 200 A. These sensors are automotive grade devices that can take the heat and deliver highly accurate open loop current sensing in the most harsh applications environments.

The Allegro medium current devices are much smaller than bulky current transformers and have the added advantage of sensing both AC and DC currents. The package design also provides galvanic isolation to 3000 VRMS and can be used in many line side applications.

My name is Berca Iulian, i`m from Romania, i have electrical engineering studies i work develop new 3Phase inverters for Brushless motors and PMSM.

I`m designing in Eagle-cad : brushless controller circuits, dc motor controller circuits,protection circuits,etc.
I`m constantly improving my design for a robust brushless controller, with all protection needed (overcurrent, over-temperature,fault output, torque control) also ramp acceleration and deceleration and adapting timing angle.
Now i also work on a new design of a large 48 pole 60kW direct drive brushless motor.

I am interested in a possible collaboration for electric car projects. How to build  and efficient brushless controller based on Motorola  MC33035  step by step. I ordered from On semiconductor as free sample 5pcs.maximum. You only pay for transport and handling.

  1. Features:
  • – Uses analogical chip with no software inside.
  • – Work only with sensored brushless motors.
  • – Speed adjustable via a potentiometer
  • – Adjustable acceleration deceleration
  • – Loop Control
  • – Fackword / Forward
  • – Dynamic breaking
  • – Over-current sense from external  shunt resistor 100mV threshold level.
  • – Overheat protection.
  • – Undervoltage protection.
  • – Fully Accessible Error Amplifier for Closed Loop Servo Applications
  • – Adjustable PWM frequency
  • – 6.25 V Reference Capable of Supplying Hall Sensor Power

I used Eagle Cad to make the schematic and the board.


New version of the schematic and it is easy to understand :

brushless controller schematic



This is another version with more mosfets in parallel and different drivers.

I used only N-channel mosfets in junction with  IR2110 half bridge mosfet driver.

You also need a inversor gate for the Top Drives (4049)

This is the newest version with 4 mosfet in parallel per switch  IR4110 but doesn`t matter what mosfet you use as the volgate and current is good for you.

top driver_cr

The pin 3 JP8  goes  to the Board 2 (Comand module) at JP20 pin 1

The pin 1 JP8 goes to Board 2 JP20 pin 2

The Pin 3 JP9 goes to the Board 2 at JP20 pin 3

The pin1  JP9 goes to the Board 2 JP20 at pin 4

The pin 3 JP10 goes to the Board 2 JP20 pin 5

The pin 1 JP10 goes to the Board 2 jp20 pin 6

The pin 1 gnd of the JP5, JP6. JP7  can be left in the air. because gnd is common.





Brushless controller schematic mc33025

In the upper part you can se the current sensor Allegro ACS758 200A.

You can also see in the left the bottom module next to it the driver+ top module.

In the right upper corner command module and in lower corner a dc-dc converter module from ebay.

to power the cmomand module and the driver board.

You can put any mosfets channel N you need. Best are with internal resistance as low as possible and higher current.

Board 3 mc33035 Brushless controller







This diagram was draw by a website visitor by name “Bill Catalena” from my specification.

Brushless controller schematic mc33035

This is the 3-rd Board with bottom mosfets.

The U,V,W need to be connected to the U,V,W to the top part of the mosfets.

The Pin 1 of the JP1 goes to the pin 2 JP5 from the Board 1

The pin 2 of the JP1 goes to the pin 2 JP6 from the Board 1

The pin 3 of the JP1 goes to the pin 2 JP7 from the Board 1

Ground pin is connected from the power supply of 48v




bottom mosfets mc33035 driver



Toyota Prius IGBT module

This toyota prius igbt module inverter was from a scrap and i took apart the driver board. now i-m building my own diver board.igbt module toyota prius

In order to be able so start the motor  you need to put a floating dc power supply to the IR2110

I have tested some of 1200V 600A FZ600R12KE3 IGBT module and the input capacitance was ~ 55nF. The time rinse obtained with avago IC ACPL-P343 was 1,2uS at 12Khz, not so good  if you want the switching losses low. the datasheet:

In this video i used 12 Mosfets irf3205z and IR2110 driverInfineon IGBT







Now the big thing : Testing the Electric Go Kart to measure the results