Nxp Usa, Inc.

Yann Cargouet

Guillaume Mouret

Thierry Sicard

Thierry Michel Alain Sicard

Tristan Bosvieux

Thierry M Alain Sicard

A calibration apparatus for a communication system. The calibration apparatus is configured to: a) set a variable termination-resistance at a receiver to a predetermined value; b) cause a transmitter to send a calibration pattern to the receiver by: setting the differential voltage on the line to a non-zero value during a non-zero-phase; and setting the differential voltage on the line to zero during a subsequent zero-phase; c) compare the differential voltage on the line during the zero-phase with a reduced-bit-value-threshold, wherein the reduced-bit-value-threshold is less than a bit-value-threshold that is used during active communication. If the differential voltage on the line during the zero-phase exceeds the reduced-bit-value-threshold, then the calibration apparatus adjusts the value of the variable termination-resistance and returns to step b). If the differential voltage on the line during the zero-phase does not exceed the reduced-bit-value-threshold, then the calibration apparatus stores the current value of the variable termination-resistance for subsequent use during active communication.

Calibration apparatus for a communication system

A bandgap reference circuit includes a first current generator having first and second bipolar transistors for generating a first current that varies proportionally as a function of temperature. A second current generator includes a field effect transistor for generating a second current that varies inversely as a function of temperature. A trimming circuit includes a third bipolar transistor sized to match the first bipolar transistor, a third current generator having a second field effect transistor coupled to a collector and base of the third bipolar transistor to generate a third current based on a base current of the third bipolar transistor, and a trim control circuit configured to modify the second current by adding the third current to or subtracting the third current from the second current based on a trim control signal. A bandgap reference current is generated by summing the first current and the modified second current.

Bandgap reference circuit with trimming circuit

A low voltage bandgap reference circuit () is provided which includes a first current generator () having first and second circuit branches which include, respectively, first and second bipolar transistors having different sizing reference values for generating a first current at a first resistor that varies proportionally as a function of temperature; a second current generator () having a third circuit branch which includes one or more field effect transistors and no bipolar transistors for generating a second current that varies inversely as a function of temperature; and a third circuit () connected to generate a bandgap reference current in response to the first current and the second current.

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Toulouse, France

Yann Cargouet