Switching Voltage Regulator
In the freeDSP ALLinONE we used a Texas Instruments LM2842YQMK for the power supply. It can provide a constant output voltage of 3.3V at input voltages from 4.5V to 42V.
The output voltage was constant as you can see in the diagram below.
The voltages we chose as input voltages represent different use cases. 5V is a typical USB voltage, coming for example from the USBi programmer or an Arduino. 12V represent a car battery, 13,7V is a fully charged car battery and 25V is two car batteries in series.
As you can see in the plots below, the ripple voltage is negligible. At 5V, the ripple voltage is about 60mV and periodically, which does not cause any problems.
The ripple decreases with increasing input voltage. At 12V we measured 50mV.
At 20V, the ripple voltage is even lower at around 40mV.
