Microchip Technology Inc.

Smsc Holdings Sarl

Clemens Kaestner

An apparatus includes a processor, USB connectors, and variable resistors or variable current sources. The processor is configured to read and load instructions causing the processor to dynamically adjust a current consumed by a given connector through adjustment of a related variable resistor or variable current source.

Load balancing in multi-port USB systems

A system, method and device for providing over-current protection to USB ports comprised in a USB hub, whereby a single switch is used to control the power supply to one or more groups of USB ports based on determinations whether the current drawn by a group of USB ports has exceeded a predefined current limit. Embodiments provide the cost savings associated with gang mode power port switching and the reduced stress on USB components and individualized protection of USB ports associated with individual mode power switching. Embodiments utilize a plurality of current measurement units to measure the current drawn by each group of USB ports supported by a switch and further utilize a power port control logic unit to control the switch based on whether the current measurements have exceeded a current limit.

USB power port control

An intelligent level shifter may be added to adjust the voltage level on the data lines (D+ and D&#x2212;) used for communications in USB systems, to address the issue of missing negative common-mode range as defined by the USB specification. The level shifter may be part of a port power controller that allows adaptive shifting of the signal level in accordance with the current levels drawn on the supply line by a device, for example during charging. The port power controller may be operated in systems enabled for battery charging, and may combine overcurrent sensing (current meter for VBus) and the routing of the D+ and D&#x2212; lines (used for the battery charging protocol) into a single package. By varying the voltage levels on the D+ and D&#x2212; data lines according to the drawn current levels, the performance of USB Hosts ports and USB Hub ports may be greatly increased.

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Rosenheim, Germany

Clemens Kaestner