Patent ID: 6509767
Filing Date: 2003-01-21
Classification: G06F

Abstract:
A wake-up circuit, comprising:a controller provided with an analog voltage input terminal and a trigger signal input terminal to output a plurality of control signals corresponding to a value of an analog voltage entered to the analog voltage input terminal; a switch unit having a plurality of switches and a plurality of resistors, the switch unit having one end grounded and another end connected to the analog voltage input terminal; and a pull-up circuit having a pull-up resistor, the pull-up circuit connecting the switch unit with a power source such that the switch unit changes, by the switches, the resistance value between the one end of the switch unit and the other end of the switch unit; and a wake-up trigger signal generator provided between the switch unit and the trigger signal input terminal, the wake-up trigger signal generator outputs a trigger signal when a voltage of the switch unit changes, thereby waking up the controller, wherein the controller is provided with a first output terminal to output a high level signal in a sleep state and a low level signal upon receiving the trigger signal, and wherein the wake-up trigger signal generator comprises a first PNP transistor having an emitter connected to the first output terminal, a collector connected to the trigger signal input terminal, and a base connected to the other end of the switch unit respectively.