A digital isolator can include: an encoding circuit configured to receive an input digital signal, and to encode a rising edge and a falling edge of the input digital signal into different encoded signals; an isolating element coupled to the encoding circuit, and being configured to transmit the encoded signal in an electrical isolation manner; and a decoding circuit configured to receive the encoded signal through the isolating element, and to decode the encoded signal to obtain the rising edge and the falling edge, in order to output an output digital signal consistent with the input digital signal.

An equalizer that has a wide variable gain range and that can implement equalization for a communication medium such as on-board wiring or a cable having various wiring lengths. The equalizer includes a core circuit and a source follower connected to a subsequent stage of the core circuit. The core circuit includes a differential pair including a first transistor and a second transistor, and a zero point generation circuit connected between a second terminal of the first transistor and a second terminal of the second transistor. The source follower includes a third transistor and a fourth transistor, a variable bias current source is connected to the third and fourth transistors, and a load in which a capacitive element and a resistor element are connected in series via a switching element is connected to wiring that connects the third and fourth transistors to an output terminal.

An integrated receiver supports adaptive receive equalization. An incoming bit stream is sampled using edge and data clock signals derived from a reference clock signal. A phase detector determines whether the edge and data clock signals are in phase with the incoming data, while some clock recovery circuitry adjusts the edge and data clock signals as required to match their phases to the incoming data. The receiver employs the edge and data samples used to recover the edge and data clock signals to note the locations of zero crossings for one or more selected data patterns. The pattern or patterns may be selected from among those apt to produce the greatest timing error. Equalization settings may then be adjusted to align the zero crossings of the selected data patterns with the recovered edge clock signal.

Various embodiments relate to an end of packet (EOP) circuit, including: a reset pulse generator circuit configured to generate a reset pulse when a input signal transitions to a new value; an analog counter circuit configured to receive a squelch signal to start the counter and to receive the reset pulse to reset the counter; and an EOP detector circuit configured to produce a signal indicative that the input signal is an EOP signal based upon an output of the analog counter circuit.

Methods and apparatus are disclosed for communicating multiple logic states across a digital isolator. The digital isolator is a universal serial bus (USB) isolator in some embodiments. The digital isolator includes one or more single-bit data channels. Three or more logic states of information are transmitted across the single-bit data channel(s). The logic states are distinguished by a pulse sequence, and in particular a number of edges of the pulse sequence and a final value or final edge of the pulse sequence.

Disclosed is a compensation circuit which includes a data analyzer that receives a first bit stream including first to N-th bits, counts a number of times of coincidence of each of first to 2.sup.M-th patterns each having an M-bit size from the first bit stream, and generates a first pattern stream including first to 2.sup.M-th count values each corresponding to the number of times of coincidence of each of the first to 2.sup.M-th patterns, and a compensation calculator that determines first to 2.sup.M-th compensation values based on the first pattern stream such that results of multiplying the first to 2.sup.M-th count values and the first to 2.sup.M-th compensation values one-to-one are even. “N” is a natural number, and “M” is a natural number smaller than “N”.

In one example, an apparatus includes an offset tunable edge slicer having an input to receive a pulse amplitude modulation signal. The offset tunable edge slicer also has a plurality of possible offset settings corresponding to a plurality of different reference voltages of the offset tunable edge slicer. A multiplexer has an output coupled to the input of the offset tunable edge slicer and an input to receive a control signal that selects one of the plurality of possible offset settings for the offset tunable edge slicer. A phase detector has an input coupled to an output of the offset tunable edge slicer.

Various embodiments relate to an end of packet (EOP) circuit, including: a reset pulse generator circuit configured to generate a reset pulse when a input signal transitions to a new value; an analog counter circuit configured to receive a squelch signal to start the counter and to receive the reset pulse to reset the counter; and an EOP detector circuit configured to produce a signal indicative that the input signal is an EOP signal based upon an output of the analog counter circuit.

A decision feedback equalizer includes a positive signal line, a negative signal line, a sense amplifier, a feedback driver, a load unit, a differential driver, and a charge pump. The differential driver maintains a difference between the first voltage of the positive signal line and the second voltage of the negative signal line at a last time point of the normal period to be equal to or greater than the reference voltage by adjusting strength of the positive input current corresponding to a positive input signal and strength of the negative input current corresponding to a negative input signal based on a temperature signal. The charge pump provides a positive offset voltage and a negative offset voltage to the positive signal line and the negative signal line, respectively. The positive offset voltage and the negative offset voltage are used to maintain an average voltage of the first voltage and the second voltage at the last time point of the normal period at a first value.

An integrated receiver supports adaptive receive equalization. An incoming bit stream is sampled using edge and data clock signals derived from a reference clock signal. A phase detector determines whether the edge and data clock signals are in phase with the incoming data, while some clock recovery circuitry adjusts the edge and data clock signals as required to match their phases to the incoming data. The receiver employs the edge and data samples used to recover the edge and data clock signals to note the locations of zero crossings for one or more selected data patterns. The pattern or patterns may be selected from among those apt to produce the greatest timing error. Equalization settings may then be adjusted to align the zero crossings of the selected data patterns with the recovered edge clock signal.