Communication device and system with ground potential difference compensation
A communication device for connection with a power source and a host device is provided. The communication device comprises a device controller and a converter circuit. The device controller is adapted for data communication with the host device and the converter circuit is configured to provide a virtual device ground at least to the device controller, so as to compensate a ground potential difference between the host device and the communication device.
1. A communication device for connection with a power source and a host device, the communication device comprising:
a device controller circuit for data communication with the host device;
one or more downstream ports for connecting one or more respective devices, different from the host device;
and
a converter circuit to provide a virtual device ground at least to the device controller circuit and to the one or more downstream ports to compensate a ground potential difference between the host device, the device controller circuit, and the one or more downstream ports of the communication device; wherein
the converter circuit comprises a compensator and a sense input, the sense input connected to the compensator, the sense input for connection to a ground potential of the host device and the compensator to control the virtual device ground based on a comparison of the ground potential of the host device with a ground potential of the communication device.
2. The communication device of claim 1 , wherein the compensator to control the virtual device ground so that a difference of potential between the virtual device ground and the ground potential of the host device is reduced.
3. The communication device of claim 1 , wherein the compensator to control the virtual device ground to match the ground potential of the host device.
4. The communication device of claim 1 , wherein the converter circuit comprises a switched-mode power supply.
5. The communication device of claim 4 , wherein the switched-mode power supply is a buck converter.
6. The communication device of claim 1 , comprising a second converter circuit, which second converter circuit for connection to the power source and to provide an internal supply voltage for the communication device.
7. The communication device of claim 6 , wherein the internal supply voltage is higher than a voltage provided by the power source.
8. The communication device of claim 6 , wherein the second converter circuit is a switched-mode power supply.
9. The communication device of claim 6 , wherein the second converter circuit comprises a ground terminal, which ground terminal is not connected to the virtual device ground.
10. The communication device of claim 1 , wherein the communication device is a USB device or a USB hub.
11. The communication device of claim 1 , wherein one or more of the downstream ports have an associated downstream power converter.
12. The communication device of claim 11 , wherein the downstream power converter is connected with the virtual device ground.
13. The communication device of claim 11 , wherein for each of the downstream ports, a dedicated associated downstream power converter is provided.
14. A communication system with a host device and a communication device, the communication device for connection with the host device and with a power source, the communication device comprising:
a device controller circuit for data communication with the host device;
one or more downstream ports for connecting one or more respective devices, different from the host device; and
a converter circuit to provide a virtual device ground at least to the device controller circuit and to the one or more downstream ports to compensate a ground potential difference between the host device, the device controller circuit, and the one or more downstream ports of the communication device; wherein
the converter circuit comprises a compensator and a sense input, the sense input connected to the compensator, the sense input for connection to a ground potential of the host device and the compensator to control the virtual device ground based on a comparison of the ground potential of the host device with a ground potential of the communication device.
15. A method of communication in a communication system with a host device and a communication device, the method comprising:
sensing a ground potential at the host device using a sense input for connection to a ground potential of the host device;
providing a virtual ground to a device controller circuit of the communication device and to one or more downstream ports, which downstream ports are for connecting one or more respective devices, different from the host device;
controlling the virtual ground based on a comparison of the sensed ground potential at the host device with a ground potential of the communication device, so that a difference of potential between the virtual ground and the ground potential at the host device is reduced; and
communicating between the host device and the communication device.
16. The communication device of claim 1 , wherein the sense input comprises a dedicated sense line that is connectable to the ground potential of the host device.
17. The communication device of claim 1 , wherein the compensator is a digital 3P3Z compensator.