Embodiments of a power-on and brown-out detector are described. In an embodiment, a power-on and brown-out detector for a power supply includes a power-on detection module, a brown-out detection module, and a logic module. The power-on detection module is connected to the power supply and is configured to generate a power-on signal in response to a voltage increase of the power supply. The brown-out detection module is connected to the power supply and is configured to generate a brown-out signal in response to a voltage charge by the power supply and a subsequent voltage decrease of the power supply. The logic module is configured to generate a control signal in response to the power-on signal and the brown-out signal. The power-on detection module is further configured to be activated or deactivated by the control signal. Other embodiments are also described.