Still waiting for my kit to arrive, which has given me time to read through the datasheets and other documentation of the bq500212A and bq51013B, as well as the evaluation modules. It really is amazing how much info, documentation and other support material TI has available at their website. If you are interested, you should really check it out!
One thing I have noticed is that, in order to check the performance of the transceiver, I will need to test it under different load conditions. I could just connect and disconnect resistors to the output, but there are better ways to do this… an electronic controllable dummy load! While looking through the web I found the great video at the EEVblog where Dave designs and builds a constant current dummy load ( http://www.youtube.com/watch?v=8xX2SVcItOA ) . So I quickly decided to go his way and try to build it myself.
So this post is going to be about my dummy load. A little bit off topic, but better than nothing while I’m waiting.
First, a Bill of Materials:
Quantity | Description | Value |
10 | Resistor 1% | 10 Ohm |
1 | Potenciometer 10 turns | 50k |
2 | Resistor 1% | 10k |
1 | Op. Amp. | LM324 |
1 | MOSFET N Channel | IRLZ 24N |
1 | Heat Sink |
|
6 | Female Banana Jack |
|
As I didn't have a MTP3055 laying around I used a IRLZ24N.
For simplicity I decided to not connect the display Dave uses in his version. Instead, I mounted to additional banana Jacks to connect the Ammeter directly.
Next thing was prototyping the hole thing:
And finally soldering it all together in a more durable manner.
<html><head><title>Jive SBS</title></head>
<body><font face="arial,helvetica,sans-serif">
<b>Error</b><br><font size="-1">
An general error occurred while processing your request.
</font></font></body></html>
I tested it with a 5V supply and was able to draw up to 1 A. With a 12V supply it got up to 2.5 A. Nevertheless I did not try to let it working at that point, as the only heat sink I could get is far too small.
I hope my kit arrives soon, as I’m now ready to start testing. If it doesn’t, I will have to come up with another small side-project for next week!