Patent ID: 7359995

Claim:
A peripheral device connection current compensation circuit for use in conjunction with a peripheral interface controller, which is to be activated when an external peripheral device is connected to the peripheral interface controller for providing a current compensation function to the externally connected peripheral device; the peripheral device connection current compensation circuit comprising: a triggering module, which is capable of being activated when the peripheral device is connected to the peripheral interface controller to generate a set of trigger signals including at least one logic-HIGH signal and a logic-LOW signal; a first N-type transistor, which has a gate, a drain, and a source, and whose gate is connected to receive the logic-HIGH signal from the triggering module to thereupon cause an electrically-conductive state between the source and the drain thereof; a second N-type transistor, which is interconnected to the first N-type transistor in such a manner as to allow the second N-type transistor to serve as a current reference for the triggering module; a third N-type transistor, which has a gate, a drain, and a source, and which is connected in such a manner that its gate is connected to receive the logic-LOW signal from the triggering module, its drain is connected to both the source of the first N-type transistor and the gate and drain of the second N-type transistor, and its source is connected to the grounding line of the peripheral interface controller; an N-type transistor clustering module, which is composed of a plurality of N-type transistors connected in parallel and in a predetermined manner that allow the N-type transistor clustering module to serve as a mirror device for the second N-type transistor, where all respective gates of the N-type transistors are connected together to the gate of the second N-type transistor, all respective drains of the N-type transistors are connected together to the minus data line of the peripheral interface controller, while all respective sources of the N-type transistors are connected together to the grounding line of the peripheral interface controller; a P-type transistor, which has a gate, a drain, and a source, and whose gate is connected to the minus data line of the peripheral interface controller, whose source is connected via a resistor to the power line of the peripheral interface controller, and whose drain is connected to drain of the first N-type transistor; and a driving module, which has an input end and an output end, and whose input end is connected to receive a control signal from the peripheral interface controller, and whose output end is connected to the minus data line of the peripheral interface controller to drive the operation of the peripheral device.