USB integrated bidirectional digital isolator channel across an interface between two USB devices
View Patent ↗An interface between USB devices employs isolation techniques to provide electrical isolation of a USB signal for transmission of the USB signal between the devices. Unidirectional isolator channels are utilized to transmit the USB signals, and a selection of an isolator channel operating in an intended direction is performed by either direction control logic or a USB hub function. Logic may be employed to detect a device attempting to initiate a USB signal. The logic operates to enable a transmitter on a receiving side and isolate the USB signal through an isolator channel operating in a transmission direction.
1. A USB isolator component for providing electrical isolation between a USB host and a USB device for communication of USB signals between the USB host and the USB device, the USB isolator component comprising:
a host bidirectional communication port for transmitting and receiving signals from and to the USB host;
a device bidirectional communication port for transmitting and receiving signals from and to the USB device;
a USB hub controller;
a host physical layer component connected between the host bidirectional communication port and the USB hub controller for transmitting and receiving signals between the host bidirectional communication port and the USB hub controller;
a device physical layer component connected between the device bidirectional communication port and the USB hub controller for transmitting and receiving signals between the host bidirectional communication port and the USB hub controller; and
isolator channels for isolating and transmitting signals;
wherein the USB hub controller is configured to analyze a USB signal to detect an initiation for a transmission of the USB signal by monitoring the USB signal for a transition from an idle state to a non-idle state, to determine a transmission direction of the USB signal based upon the analysis and the detection of the initiation for the transmission, and to enable a transceiver of the USB device if the transmission direction is from the USB host to the USB device or of the USB host if the transmission direction is from the USB device to the USB host;
wherein the USB signal is transmitted from the USB hub controller to an isolator channel configured to isolate the USB signal in the transmission direction and transmit the isolated USB signal to the enabled transceiver.
2. The USB isolator component of claim 1 , wherein one or both of the host physical layer component or the device physical layer component is divided into a clock data recovery component and a transceiver component.
3. The USB isolator component of claim 2 , wherein the isolator channels are connected between the clock data recovery component and the transceiver component of the divided host physical layer component or the divided device physical layer component.
4. The USB isolator component of claim 1 , wherein the isolator channels are connected between the USB hub controller and the host physical layer component or the device physical layer component.
5. The USB isolator component of claim 1 , wherein the USB hub controller is further configured to analyze the USB signal to detect a completion of the transmission of the USB signal and to disable the enabled transceiver.
6. The USB isolator component of claim 5 , wherein the USB hub controller configured to analyze the USB signal to detect the completion of the transmission of the USB signal comprises the USB hub controller configured to monitor the USB signal for a transition from a non-idle state to an idle state.
7. The USB isolator component of claim 5 , wherein the USB hub controller configured to disable the enabled transceiver comprises the USB hub controller configured to disable the enabled transceiver after a predetermined number of cycles elapse after the detection of the completion of the transmission of the USB signal.