IC CD4093 Based PWM DC Motor Controller Circuit

IC CD4093 Based PWM DC Motor Controller Circuit is a great way to control how fast a direct current DC motor runs while also saving energy.

By changing the duty cycle of the PWM signal, you can adjust the average voltage sent to the motor which helps you control its speed accurately.

This circuit design includes a quad NAND Schmitt trigger chip the CD4093 and a MOSFET for switching ensuring the motor runs smoothly and efficiently.

It is important to use a 12V power supply that can provide at least 5A of current for this setup.

Circuit Working:

Parts List:

In this article the first stage of the circuit is oscillator stage the NAND gate of the IC1 CD4093 chip acts like a simple astable multivibrator creating a square wave signal.

The frequency of this signal depends on the resistor R1 the adjustable resistor VR1 and the capacitor C1.

The second stage is PWM generation the duty cycle of the square wave is controlled by the diodes D1 and D2 along with the variable resistor VR1.

By changing the resistance of VR1 you can adjust how long capacitor C1 takes to charge and discharge which changes the duty cycle of the PWM signal.

The third stage is signal processing stage in which the output pin goes to the other NAND gates.

These gates help to buffer and refine the signal so that it can properly drive the MOSFET Q1.

The last stage is motor control where the Q1 MOSFET acts like a switch turning the motor on and off very quickly.

This fast switching controls the motors speed based on the duty cycle of the PWM signal.

Also, the flyback diode D3 is added to protect the circuit from any voltage spikes that the motor might create.

Formulas with Calculations:

Below mentioned are the formulas with calculations for IC CD4093 Based PWM DC Motor Controller Circuit:

Frequency of Oscillator (Astable Multivibrator):

The frequency (f) of the PWM signal is calculated using the formula:

f = 1.44 / ((R1 + 2VR1) × C1)

where

• R1 is 1k resistor
• VR1 is 100k variable resistor (potentiometer)
• C1 is 10nF capacitor

Given values:

R1 = 1kΩ = 1000Ω

VR1 = 100kΩ = 100000Ω (variable)

C1 = 10nF = 10 × 10⁻⁹ F

Substituting values:

f = 1.44 / ((1000 + 2 × 100000) × (10 × 10⁻⁹))

f = 1.44 / ((1000 + 200000) × 10⁻⁸)

f = 1.44 / (201000 × 10⁻⁸)

f = 1.44 / 0.00201

f = 716 Hz

Thus, the PWM frequency is approximately 716 Hz and it varies depending on the position of the potentiometer VR1.

How to Build:

To build a IC CD4093 Based PWM DC Motor Controller Circuit follow the below mentioned steps for connections and assembling:

• Assemble all the components as mentioned in the above circuit diagram
• Connect pin 1 to pin 2 of IC1 CD4093
• Connect pin 5 and pin 6 of IC1
• Connect pin 8 and pin 9 of IC1
• Connect pin 12 and pin 13 of IC1
• Connect pin 7 of IC1 to GND of the circuit.
• Connect pin 14 of IC1 to +12V DC
• Connect pin 3 to common inputs of all the other gates
• Connect a parallel diode D1 and D2 from pin 3 of IC1
• Connect a pot VR1 one leg to cathode of D1 and other leg of pot to anode of D2.
• Connect the center leg of VR1 pot to one end of resistor R1 and other end of R1 resistor connect to pin 1 and pin 2
• Connect capacitor C1 one end to resistor R1 and other end of C1 to GND.
• Connect a capacitor C2 one end to +12V DC and other end of C1 connect to GND.
• Connect the GATE pin of MOSFET Q1 to pin 10 of IC1,connect the DRAIN pin of Q1 to anode of D3 diode and cathode of diode D3 connect to motor + DC.
• Connect the 12V DC motor parallel to diode D3.
• Connect the SOURCE pin of Q1 MOSFET to GND.

Conclusion:

This IC CD4093 Based PWM DC Motor Controller Circuit is great at managing the speed of DC motors while wasting very little power.

It uses a CD4093 IC to create the PWM signal and a MOSFET to switch things on and off, which helps it work really well.

Users can change the speed of the motor by turning a variable resistor so this setup can be used for different things like fans, robots and controlling motors in factories.

References:

Datasheet IC CD4093