In a wireless charging system having a power transmitter (TX) and a power receiver (RX), the RX has a rectifier that rectifies an AC power signal received wirelessly from the TX into a rectified DC power signal. The RX also has regulation modules that monitor the DC power signal at various different voltage regions having one or more different high-voltage regions and one or more different low-voltage regions. Each regulation module affects operations of the wireless charging system in a different way. The regulation modules protect the RX from both over-voltage and under-voltage conditions.