Replace your old 78xx voltage regulators with this much more efficient pin-compatible buck converter.
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| Parameter | Value |
|---|---|
| Input Voltage | 4.5V - 16V |
| Output Voltage | Selectable via Resistors R1 and R2: V = 0.6 * (R1 / R2 + 1) |
| Output Current | max 2A |
| Output Voltage | R1 | R2 |
|---|---|---|
| 12.2V | 91kΩ | 4.7kΩ |
| 12V | 82kΩ | 4.3kΩ |
| 9.2V | 43kΩ | 3kΩ |
| 9V | 140kΩ | 10kΩ |
| 6.2V | 140kΩ | 15kΩ |
| 6V | 102kΩ | 11.3kΩ |
| 5.2V | 115kΩ | 15kΩ |
| 5V | 110kΩ | 15kΩ |
| 3.4V | 56kΩ | 12kΩ |
| 3.3V | 115kΩ | 25.5kΩ |
When I find the time I'll hook up an oscilloscope. However, you can basically assume that there is a certain amount of switching noise. Unfortunately, this is the disadvantage of the DC/DC converters.
Would be nice to publish a table of normally available resistor values for various desired output voltages, especially the commonly used 780x regulators (and AMS1117 series).
I love this idea! Does yours have a decreasing voltage as the current goes up though - Am I reading that graph correctly? What's causing that, and can it be mitigated?
On the one hand, this is due to the DC/DC converter itself (at least all converters that I know behave like this according to their datasheets), as well as to the resistance of the tracks, connectors and cables. You can't really prevent this, but you can choose the feedback resistors so that the output voltage is slightly higher (e.g. 5.2V).
Your second graph trends above unity. Quick, to production! Limitless energy is at our fingertips. Love the project.
Nope. Gleeful and ignorant late night perusal. Carry on..
The efficiency test diagrams are neat! How did you create them? Is it automated?
Yes, it's automated: https://github.com/wagiminator/ATtiny814-Power-Analyzer
Stefan Wagner
misbahmemon13
electronicsworkshops
what about 79xx series (negative voltage)?