Power supply board for my two wheeled robot. 5 and 3.3V provided by TI LDO regulators at 3A each, and fused vbatt for the motors. PPTC rated 3A IH at 12V. Protection from over voltage condition (important when combining motors and MCUs) using crowbar circuits. Divider and space reserved for a tiny85 to monitor battery voltage.
So testing on the first iteration on this board ended in a fit of curses too salty to repeat here. Decided to make another attempt, and incorporate the (painful) lessons from my first try. Opted for non-bussed perf board, and arranged components so their leads could be used to make connections.
Much neater rats nest on the flip side. Watch this post for updates on how this tests out.
Last night, I soldered my voltage comparator circuit onto a small protoboard for my EE40LX final project. The circuit is a window comparator, and allows adjustment of the flex sensor’s divider, as well as one side of the window. This allows for adjustment on install and over time, as resistance may change with wear.
Over-voltage protection for each rail of my project’s power supply in the form of a thyristor (silicon controlled rectifier or SCR) based crowbar circuit. The Zener breakdown voltage determines the cut off and trips the gate of the SCR, causing a short condition. The short is then handled by a fuse, protecting sensitive devices. A threshold of about 1V for the Zener diodes (4.3V for the 3.3V rail & 6.2V for the 5V rail) was selected to allow for overhead in case of transient spikes.