Altera Corporation

Kok Siang Tan

Tim Tri Hoang

Chuan Khye Chai

Wilfred Wee Kee King

A driver circuit drives data to an output based on an input data signal in a transmission mode. The driver circuit includes transistors. A comparator generates a comparison output in a calibration mode based on a reference signal and a signal at the output of the driver circuit. A calibration control circuit adjusts an equivalent resistance of the transistors in the driver circuit based on the comparison output in the calibration mode. The equivalent resistance of the transistors in the driver circuit can be adjusted to support the transmission of data according to multiple different data transmission protocols using transmission links having different characteristic impedances. The equivalent resistance of the transistors in the driver circuit can also be adjusted to compensate for resistance in the package routing conductors and/or to compensate for parasitic resistance.

Circuits and methods for impedance calibration

An integrated circuit having a regulator circuit capable of tracking reference voltages is provided. The integrated circuit includes shunt regulator circuitry. The shunt regulator circuitry includes a shunt regulator circuit and a voltage tracking circuit. The shunt regulator circuit has an output on which a regulated voltage is provided. The shunt regulator circuit also provides electrical current to the output when the regulated voltage is outside of a voltage range bounded by first and second reference voltages. The voltage tracking circuit may be coupled to the shunt regulator circuit. The voltage tracking circuit may generate the first and second reference voltages. In one instance, the first voltage is greater than the regulated voltage and the second voltage is less than the regulated voltage.

Growing community of inventors

Bayan Lepas, Malaysia

Kok Siang Tan