A method includes detecting removal or depletion of a power supply associated with a powered device. The powered device is configured to receive power from a power adapter via a narrow-voltage direct current/direct current (NVDC) charger and from the power supply. The method also includes, in response to the detection, disabling a dynamic power management function of the NVDC charger. The method further includes monitoring input current or input power provided to the powered device by the NVDC charger and determining if the input current or input power exceeds a threshold. In addition, the method includes, if the input current or input power exceeds the threshold, triggering a throttling of an operating clock frequency of the powered device. The method could also include (i) disabling a specified mode of operation and turning on a voltage regulator of the NVDC charger in response to the detection and (ii) providing over-voltage protection.