This Lab will use the following Lab Resources:

Virtual Lab - Citrix

Adobe Creative Cloud

STEP 1: Design a Boost Regulator

Design a buck regulator using a LM2585 to convert an unregulated input voltage of 10 Vdc to an output of 24 Vdc at 0.5 Adc. Use a controller frequency of 100 kHz. Assume that the transistor has an on resistance of 0.4 and that the diode drop 0.5 Vp when it is on. Select and properly specify all necessary components. Assume that the ambient temperature is 50 C. Show all necessary work for full credit.

Be sure to calculate the power and current that must be provided to the regulator, the inductor's inductance and current ratings, the power that the transistor and the diode must dissipate, and the value of the output capacitor.

Once the components have been properly selected, go to a vendor like Digikey, Newark, or Radio Shack and find the component part numbers. Change your design if necessary to be able to use components that are readily available.

Calculate the feedback resistors, power, and current that must be provided to the LM2585 regulator, the power that the IC must dissipate, and the junction temperature assuming that the ambient temperature is 50 C with no heat sink.

Listen

STEP 2: Boost Regulator Build and Test (Hardware Option)

This section of the lab explores the actual hardware configuration.

OBJECTIVE: Given the boost regulator schematic from above, build the circuit and test the stated voltages and currents and compare to the results to those found in simulation found.

DESCRIPTION: Once the buck regulator circuit is built, connect a 100 kHz, 50% duty cycle rectangular wave to the MOSFET gate to drive the converter. Test the output current and voltage and verify that the converter operation. Using the oscilloscope, graph and fully characterize the MOSFET switch operation. Thoroughly test the converter's line and load regulation characteristics.

BACKGROUND: Chapters 7 and 9 of the text introduce the concepts of the boost converter switching circuit and its characteristics and applications.

Listen

STEP 3: Questions and Discussion

Explain fully the operation of the LM2585 Boost Regulator IC.

What is the difference between a boost and a flyback converter?

Observations/Measurements: A. The Buck Regulator Schematic 1. Paste the diagram of the schematic for your design below: 2. Paste your parts list for your design below: 3. Calculated values for important parameters: a. Power provided to regulator = b. Current provided to regulator = c. Inductance of inductor = d. Power that transistor and diode must dissipate = e. Value of output capacitor = f. Power to be provided to LM2585 = g. Current to be provided to LM2585 = h. Values for the feedback resistors = i. Junction temperature = B. The Boost Regulator Build and Test 1. Paste the Test results below: 2. Test parameters: c. Output Current = d. Voltage Current = 3. Paste Oscilloscope graph below: C. Questions/Discussion 1. Explain fully the operation of the LM2585 Buck Regulator IC 2. What is the difference between a boost and a flyback converter