Patent ID: 8862921

Claim:
An apparatus for remote wake-up during dedicated charging mode comprising: a USB transceiver port; a USB connector port; a switch network selectively coupling said USB transceiver port to said USB connector port; control logic coupled to said switch network and operative to control said switch network to disconnect said USB transceiver port from said USB connector port during a dedicated charger operational mode and to connect said USB transceiver port to said USB connector port upon detection of a potential remote wake-up condition to exit a sleep, standby or hibernate mode when a USB remote wake-up device is connected to said USB connector port; and signature detection circuitry between said USB connector port and said control logic to differentiate between USB devices to be charged and USB remote wake-up devices, said signature detection circuitry including a plurality of series connections of a comparator and a debouncer comprising (a) a first comparator having a positive input coupled to a D+ line of said USB connector port, a negative input coupled to a first reference voltage, and an output coupled to an input of a first debouncer, said first debouncer having an output, (b) a second comparator having a negative input coupled to a D− line of said USB connector port, a positive input coupled to a second reference voltage, and an output coupled to an input of a second debouncer, said second debouncer having an output, (c) a third comparator having a negative input coupled to said D− line of said USB connector port, a positive input coupled to a third reference voltage, and an output coupled to an input of a third debouncer, said third debouncer having an output, (d) a fourth comparator having a negative input coupled to said D− line of said USB connector port, a positive input coupled to a fourth reference voltage, and an output coupled to an input of a fourth debouncer, said fourth debouncer having an output, and (e) a bias resistor coupled between said D− line of USB connector port and ground.