Testing
This section is testing the power supply. Showing waveforms needed for the power supply.
Testing TPS54560
The waveforms to the right show the TPS54560 outputting in a no load and high load condition. The Vripple can be seen.
TPS54560 Vout (no-load) blue is before inductor, yellow is after inductor
TPS54560 Vout (100mA) blue is before inductor, yellow is after inductor
Testing LM2679
The waveforms to the right show the LM2679 outputting in a no load and high load condition. The Vripple can be seen.
LM2679 Vout (no-load)
Blue is SW pin
Yellow is Vout
LM2679 Vout (high-load)
Blue is SW pin
Yellow is Vout
Testing LM2673
The waveforms show the AC coupling of the output with no load, and the pure voltage with a 100mA load. The 100mA represents the current draw of the nano and display. Making the graph accurate to the real world.
LM2673 Vout (no-load) with scope on AC
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LM2673 Vout (100mA load)
Blue is SW pin
Yellow is Vout
Testing the Current Measurement
Using a programmable power supply I can activate the current measurement.
The accuracy is good with an error of 20%. Though this could be due to the bread board. Meaning with the arduino on an actual PCB I expect the measurements to be even more accurate.
Current reading while drawing 1A from a programmable load.
Current reading while drawing 500mA from a programmable load.
Current reading while drawing 0mA from a programmable load.
Making the LM2679 better
When I was testing the LM2679 I noticed it's very sensitive to the input voltage. I added more and different capacitors to smooth the input voltage and got fantastic results.
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Adding the 1uF gave superior results in terms of the spike. It also increased my current limit. I couldn't even draw 100mA without the cap. With the cap I could easily dray 300mA.
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Going from a 1uF ceramic to a 1uF and 470nF not only decreased the spike but also gave a higher output voltage. This is a desired result as my potentiometer is set to the maximum. Meaning the LM2679 will hit the highest voltage possible. Therefore if the output voltage is higher then the LM2679 gets an increased range of operation.​ I could also draw close to 1A.​
Yellow is Vin, Blue is Vout. LM2679 with 33uF capacitor.
Yellow is Vin, Blue is Vout. LM2679 with 33uF capacitor and 1uF ceramic.
Yellow is Vin, Blue is Vout. LM2679 with 33uF capacitor, 1uF ceramic and 470nF ceramic.