US Patent 11774993 Power supply management device and power supply management method

A power supply management device includes an internal power supply circuit, switches, a comparator circuit, and a control circuit. The internal power supply circuit is configured to output a first supply voltage to a node. The switches are coupled between the node and a plurality of first circuits. The comparator circuit is configured to compare a voltage on the node with a reference voltage when the node does not receive the first supply voltage to generate a flag signal. The control circuit is configured to determine whether the node receives a second supply voltage from an external power supply circuit according to the flag signal. If the node receives the second supply voltage, the control circuit is further configured to turn off the internal power supply circuit and gradually turn on the switches, in order to provide the second supply voltage to the first circuits via the switches.