Patent ID: 7644217

Claim:
Universal Serial Bus (USB) capable device having power saving features, comprising: a USB peripheral comprising a USB transceiver having USB data lines, a USB voltage regulator, a serial interface and USB logic, wherein the USB voltage regulator is switchably coupled to a power supply voltage; a strong pull-up resistor coupled to a one of the USB data lines and switchably coupled to the USB voltage regulator; and a weak pull-up resistor coupled to the one of the USB data lines and the power supply voltage; wherein when voltage on the one of the USB data lines is greater than a reference voltage, the USB peripheral is inactive, the strong pull-up resistor is disconnected from the USB voltage regulator and the USB voltage regulator is disconnected from the power supply voltage, whereby the USB peripheral draws minimal power, and when the voltage on the one of the USB data lines is less than the reference voltage a USB detection signal is generated to activate the USB peripheral, thereby connecting the strong pull-up resistor to the USB voltage regulator and connecting the USB voltage regulator to the power supply voltage.