Techniques for interpolating two voltages without loading them and without requiring significant power or additional area are described. The techniques include specific topologies for the buffering amplifiers that offer accuracy by cancelling systematic error sources without relying on high gain, thus simplifying the frequency compensation, and reducing power consumption. This can be achieved by biasing the amplifiers from the load current by an innovative feedback structure, which can remove the need for high impedance nodes inside the amplifiers.

An asymmetric signal path approach is used to extract differential signals out of the photodetector (e.g., a photodiode) for amplification by a differential transimpedance amplifier (TIA). This asymmetric-path differential TIA configuration has less low-frequency Inter Symbol Interference (ISI) (also known as Baseline Wander), less high-frequency noise amplification, and higher bandwidth capabilities. There is no power penalty with this design in comparison to a single-ended TIA, can extend the range of the link for a given system power consumption, and can decrease transmitter power for a given range.

Techniques for interpolating two voltages without loading them and without requiring significant power or additional area are described. The techniques include specific topologies for the buffering amplifiers that offer accuracy by cancelling systematic error sources without relying on high gain, thus simplifying the frequency compensation, and reducing power consumption. This can be achieved by biasing the amplifiers from the load current by an innovative feedback structure, which can remove the need for high impedance nodes inside the amplifiers.

A DC offset cancellation circuit and a DC offset cancellation method are disclosed. The DC offset cancellation circuit comprises a high-speed amplifier, a voltage comparator, a microprocessor, and a digital-to-analog converter. The high-speed amplifier comprises an input stage with a DC offset cancellation function, an amplification stage, and an output buffer stage. The voltage comparator is connected to the output buffer stage. The microprocessor is connected to the voltage comparator. The digital-to-analog converter is connected to the microprocessor. The digital-to-analog converter is connected to the input stage.

Various embodiments of the present technology may comprise methods and apparatus for driver calibration. The methods and apparatus may comprise various circuits and/or systems to minimize an offset output current (e.g., a drive current) due to an offset voltage in an operational amplifier. The methods and apparatus may comprise a current comparator circuit and a replica circuit that operate in conjunction with each other to monitor the drive current and provide a feedback signal, which is then used to adjust the drive current and improve the accuracy of the drive current.

A transconductance amplifier includes a first MOS transistor configured to receive a first voltage at a first node and output a first current to a fifth node in accordance with a third voltage at a third node; a second MOS transistor configured to receive a second voltage at a second node and output a second current to a sixth node in accordance with a fourth voltage at a fourth node; a third MOS transistor configured to output a third current to the third node in accordance with a fifth voltage at the fifth node; a fourth MOS transistor configured to output a fourth current to the fourth node in accordance with a sixth voltage at the sixth node; and a source degeneration network placed across the third node and the fourth node.

An internal voltage offset between a positive input and a negative input of a first operational amplifier is compensated. The negative input and the positive input of the first operational amplifier are coupled at the same voltage level. A comparison current generated at an output of the first operational amplifier has a sign that is representative of a sign of the internal voltage offset. The output of the first operational amplifier is biased to a threshold voltage using a current-to-voltage converter. A control voltage is generated from a sum of the threshold voltage and a voltage conversion of the comparison current. Compensation for the internal voltage offset between the positive and negative inputs of the first operational amplifier is made dependent on the control voltage.

A current sensing topology uses an amplifier with capacitively coupled inputs in feedback to sense the input offset of the amplifier, which can be compensated for during measurement. The amplifier with capacitively coupled inputs in feedback is used to: operate the amplifier in a region where the input common-mode specifications are relaxed, so that the feedback loop gain and/or bandwidth is higher; operate the sensor from the converter input voltage by employing high-PSRR (power supply rejection ratio) regulators to create a local, clean supply voltage, causing less disruption to the power grid in the switch area; sample the difference between the input voltage and the controller supply, and recreate that between the drain voltages of the power and replica switches; and compensate for power delivery network related (PDN-related) changes in the input voltage during current sensing.

An asymmetric signal path approach is used to extract differential signals out of the photodetector (e.g., a photodiode) for amplification by a differential transimpedance amplifier (TIA). This asymmetric-path differential TIA configuration has less low-frequency Inter Symbol Interference (ISI) (also known as Baseline Wander), less high-frequency noise amplification, and higher bandwidth capabilities. There is no power penalty with this design in comparison to a single-ended TIA, can extend the range of the link for a given system power consumption, and can decrease transmitter power for a given range.

A DC-DC converter according to an embodiment is a DC-DC converter for generating an output voltage VOUT according to a reference voltage VREF, and includes a fully differential amplifier that outputs a first differential output signal and a second differential output signal according to a differential input using the reference voltage VREF and the output voltage VOUT, a pulse width modulation signal generation circuit that generates a pulse width modulation signal based on the first differential output signal Vout1 and the second differential output signal Vout2, and a driver that outputs a driving signal obtained by waveform-shaping the pulse width modulation signal.