DC Electronic Load V2.0 Project under development

This project is an upgrade for DC Electronic Load V1.0, click on the link to read more about its specs and general information. This page will only discuss the changes done to it.

Display

I have upgraded the display from the 128x64 monochrome dot matrix LCD to a multi-colour 2.2" TFT. The new display has a higher resolution at 240x320 which allows me to display more information with better quality and colour coding. However the new display I chose is smaller in physical size therefore I might change it to one with the same size as the old version but still has the colour and higher resolutions. The display has it's own microcontroller that communicates with the main microcontroller using Serial. This releases some pressure on the main controller resulting in faster response.

Modes of Operations

This version will have three different modes of operation:

Constant Current
The same mode as v1.0, where it maintains the set current no matter what the input voltage is.

Constant power
Unlike constant current, constant power is software controlled. This means that the unit still reads and controls the current, combined with the voltage reading, it does real time calculations to maintain the power constant according to the set value. This naturally makes it slower to respond.

Constant Resistance
same as power mode, it is software controlled. where it does real time calculations to maintain constant resistance.
Schematic

I have done a few improvements on the schematic. The fan controller is now has better hysteresis. I also added the controller for the new display. and general improvements.

Figure 1
PCB Design

The PCB now includes the fan controller on it instead of a separate board. I also improved on the dimensions and the placements of the DC plugs, heatsinks and other components.

Figure 2
Figure 3
Gallery