EET 153: Power Supply Specifications

Component Constraints:

    Maximum Cost of All Components: $40

    Only Approved Component Sources: Jameco or Digi-Key

Physical Requirements:

    Maximum Height 6 inches

    Maximum Width 12 inches

    Maximum Depth 10 inches

    Output connectors, power-on indicator, voltmeter, and all controls must be on the front panel.

    Grounded power cord and fuse holder must be on the rear panel.

    The case must be completely enclosed, except for ventilation holes.

    Maximum Operating Conditions:

        Temperature 10 degrees C to 40 degrees C

        Relative Humidity (Noncondensing) 10% to 80%

        Maximum Drop Height 0.05 m (No interruption)

        Vibration 1.25 g at 3 Hz (No interruption)

    Maximum Storage Conditions:

        Relative Humidity (Noncondensing) 10% to 90%

        Maximum Drop Height 0.1 m (No damage)

        Vibration 1.5 g at 3 Hz (No damage)

    Maximum Mean Time Between Failures (MTBF) 100 hours (Really easy!)

    Maximum Mean Time To Repair (MTTR) 1 hour

        On/Off switch on front panel with indicator light

        Voltage adjustment knob and voltmeter on front panel

    Safety:

        Fuse protected

        No user access to line voltages

        Short-circuit protected

    Input:

        Nominal input voltage 120 VAC

        Phasing 1-phase

        Frequency 60 Hz

    Output:

        Choose one of the following two output options:

            Output Option 1 (Single Variable Output):

                 Minimum output voltage range 2 VDC to 12 VDC
                 Minimum full-load output current 1 A
                 Maximum ripple (@ 1 A) 1% (120 mVpp for 12 VDC)

            Output Option 2 (Two Fixed Outputs):

                 Output A:

                    Maximum output voltage range 5 VDC ± 5%
                    Minimum full-load output current 500 mA
                    Maximum ripple (@ 500 mA) 1% (50 mVpp)

                Output B:

                    Maximum output voltage range 12 VDC ± 5%
                    Minimum full-load output current 500 mA
                    Maximum ripple (@ 500 mA) 1% (120 mVpp)

Proto-board construction is not acceptable. Use a permanent or semi-permanent construction method such as soldering on a printed circuit board, point-to-point soldering on a perforated board, or wire-wrapping using the appropriate sockets mounted to a perforated board. An enclosure is required. The University will pay up to $30 for parts and materials that are ordered through the instructor.  In return, the power supply will become the property of the Computer Science & Engineering Department.  Be sure to order your parts early enough to complete the project.

A written functional description must be submitted that describes the design steps and circuit operation in sufficient detail to demonstrate your knowledge. It must be written at a college level and be free from spelling and grammar errors. Include calculations, schematic diagrams, assembly diagrams, and component data sheets as appropriate.

It must also explain how you verified that the power supply meets, or exceeds, all of its specifications. The project must be explained and demonstrated in a class presentation.

The details of how to design a variable-output power supply using an IC, such as the LM317, will not be covered in class. Power supplies with multiple regulated outputs will also not be discussed. You must research these topics yourself. Do not simply copy another design. You must quantitatively show in your functional description how and why you selected each component. This will be impossible if you simply copy a design. If your design process is not sufficiently documented, I will assume you did not design it yourself and give you a zero.

You must work as a 3-person team on this project. You will be graded on the skill level demonstrated by your design, the quality of construction, adherence to specifications (including correct operation), the comprehensiveness of the documentation, the team's presentation, and your contribution to the team.