DC to DC converters IC UC3524

[nonny]

TOPIC: DC-DC converter controlled DC motor drive
I need HELP !!!!!!!!!!!!!!

OBJECTIVES: To design, test and demonstrate a DC-DC converter circuit based on IC UC3524.

SPECIFICATIONS:

• Power supply to the circuit = 10V DC.
• The output of the circuit should be PWM (Pulse width modulated) waveform.
• The chopper frequency = 1kHz - 4kHz. Assigned frequency = 2000Hz
• The duty cycle should be manually variable from 0 to 100% such that the motor speed varies between zero and maximum speed.
• There circuit should have emergent stop function to stop the motor without power-off the control circuit.
• The motor speed should also be variable by “rheostat speed control”.
• The block diagram of the circuit is shown in Figure 1.
• The PWM waveform is shown in Figure 2.
• Use 3 LEDs to indicate the operation state:
- Green  Power on
- Red  Load motor in operation
- Yellow  In emergent stop

DESIGN CONSIDERATIONS:
• The circuit should be designed using UC3524 to obtain the specified frequency and variable duty cycle.
• A MOSFET is used as the chopper switch as shown in Figure 1 and the waveform as in Figure 2.
• After successful testing on resistive load, the circuit is then used to drive a DC motor and realize variable speed control.
• As the output voltage is of the PWM form, a D flip-flop working in toggle mode is used keep the RED LED at constant brightness.