A first receiver receives second serial data transmitted from a second circuit. A second receiver receives first serial data transmitted from a first circuit. An automatic adjustment circuit generates a control signal so as to reduce an error rate of the first serial data received by the second receiver. A second driver drives a differential transmission path according to the second serial data including the control signal. An operation parameter of a first driver is set based on the control signal included in the second serial data.

In a Power over Data Lines (PoDL) system that conducts differential data and DC power over the same wire pair, various DC coupling techniques are described that improve DC voltage coupling while attenuating AC common mode noise. Pairs of differential mode chokes (DMCs) are used to share current supplied by a single phase or multi-phase power supply. In one embodiment, one DMC is coupled to the line side of a common mode choke (CMC), and one DMC is coupled to the PHY side of the CMC. The line-side DMC has windings that are loosely magnetically coupled so that DMC does not present a very low impedance to AC common mode noise on the wires. Therefore, the performance of the wires' RC termination circuitry is not adversely affected by the line-side DMC when minimizing reflections of common mode signals.

A high-speed signaling system with adaptive transmit pre-emphasis. A transmit circuit has a plurality of output drivers to output a first signal onto a signal path. A receive circuit is coupled to receive the first signal via the signal path and configured to generate an indication of whether the first signal exceeds a threshold level. A first threshold control circuit is coupled to receive the indication from the receive circuit and configured to adjust the threshold level according to whether the first signal exceeds the threshold level. A drive strength control circuit is coupled to receive the indication from the receive circuit and configured to adjust a drive strength of at least one output driver of the plurality of output drivers according to whether the first signal exceeds the threshold level.

The present disclosure describes exemplary line drivers for use in an exemplary wireline transmission device. In some situations, the exemplary line drivers are electrically connected to a wireline communication channel to transmit information. The exemplary line drivers prevent charge sharing with the wireline communication channel. The exemplary line drivers disclosed herein charge various circuit nodes to various logical values, such as a logical zero or a logical one, to prevent charge sharing with the wireline communication channel.

The present disclosure provides a hybrid-mode laser drive circuit and an optical emitting system. An equalizer circuit is configured to generate, according to a data signal and a clock signal, an equalization signal for compensating a hybrid-mode laser drive circuit; the hybrid-mode laser drive circuit is connected to an output end of the equalizer circuit, and is configured to generate a corresponding drive signal according to an output signal of the equalizer circuit, so as to drive a light emitting diode to generate a corresponding optical signal; a third current source is connected between a power supply voltage and an output end of the hybrid-mode laser drive circuit; an anode of the light emitting diode is connected to the output end of the hybrid-mode laser drive circuit and a cathode of the light emitting diode is connected to a power supply ground.

A bidirectional data link includes a forward channel transmitter circuit and a forward channel receiver circuit. The forward channel transmitter circuit includes a forward channel driver circuit, and a back channel receiver circuit. The back channel receiver circuit is coupled to the forward channel driver circuit. The back channel receiver circuit includes a summation circuit and an active filter circuit. The summation circuit is coupled to the forward channel driver circuit. The active filter circuit is coupled to the summation circuit. The forward channel receiver circuit includes a forward channel receiver, and a back channel driver circuit. The back channel driver circuit is coupled to the forward channel receiver.

A hybrid voltage mode (VM) and current mode (CM) four-level pulse amplitude modulation (PAM-4) transmitter circuits (a.k.a. drivers) is calibrated using a configurable replica circuit and calibration control circuitry. The replica circuit includes an on-chip termination impedance to mimic a receiver's termination impedance. The amount of level enhancement provided by the current mode circuitry is calibrated by adjusting the current provided to the output node and sunk from the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving an intermediate PAM-4 level. After the level enhancement has been set, the non-linearity between levels is calibrated by adjusting the amount of current provided to the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving a maximum output voltage level.

The present disclosure describes exemplary line drivers for use in an exemplary wireline transmission device. In some situations, the exemplary line drivers are electrically connected to a wireline communication channel to transmit information. The exemplary line drivers prevent charge sharing with the wireline communication channel. The exemplary line drivers disclosed herein charge various circuit nodes to various logical values, such as a logical zero or a logical one, to prevent charge sharing with the wireline communication channel.

A bidirectional data link includes a forward channel transmitter circuit and a forward channel receiver circuit. The forward channel transmitter circuit includes a forward channel driver circuit, and a back channel receiver circuit. The back channel receiver circuit is coupled to the forward channel driver circuit. The back channel receiver circuit includes a summation circuit and an active filter circuit. The summation circuit is coupled to the forward channel driver circuit. The active filter circuit is coupled to the summation circuit. The forward channel receiver circuit includes a forward channel receiver, and a back channel driver circuit. The back channel driver circuit is coupled to the forward channel receiver.

A PoDL system conducts differential data and DC power over the same wire pair, and various DC coupling techniques are described that improve DC voltage coupling while attenuating AC common mode noise. Pairs of differential mode chokes (DMCs) are used to share current supplied by a power supply. In one embodiment, one DMC is coupled to the line side of a common mode choke (CMC), and one DMC is coupled to the PHY side of the CMC. The line-side DMC has windings that are loosely magnetically coupled so that DMC does not present a very low impedance to AC common mode noise on the wires. Therefore, the performance of the wires' RC termination circuitry is not adversely affected by the line-side DMC when minimizing reflections of common mode signals. The DMCs may use the same magnetic core, and the CMC may be series CMCs that used the same magnetic core.