A class D amplifier circuit receives an analog audio signal with a first reference voltage as its center level, and outputs an output pulse signal having a duty cycle that corresponds to the analog audio signal. A bias circuit generates a second reference voltage having a voltage level obtained as a division of the first reference voltage and the power supply voltage. A periodic voltage generating circuit of the class D amplifier circuit generates a periodic voltage having a triangle waveform or otherwise a sawtooth waveform having an amplitude that corresponds to the second reference voltage.

A transformer includes a primary winding and a secondary winding. A transmitting circuit is coupled to a primary winding of a transformer and supplies a current signal to the primary winding with a polarity that changes in response to a change of the input signal level. A latch circuit is arranged such that its set terminal is coupled to one end of the secondary winding of the transformer, and its reset terminal is coupled to the other end of the secondary winding of the transformer. A first switch is arranged between a common voltage node at which a common voltage occurs and the set terminal. When the output of the latch circuit is high, the first switch is turned on. A second switch is arranged between the common voltage node and the reset terminal. When the output of the latch circuit is low, the second switch is turned on.

A transformer includes a primary winding and a secondary winding. A transmitting circuit is coupled to a primary winding of a transformer and supplies a current signal to the primary winding with a polarity that changes in response to a change of the input signal level. A latch circuit is arranged such that its set terminal is coupled to one end of the secondary winding of the transformer, and its reset terminal is coupled to the other end of the secondary winding of the transformer. A first switch is arranged between a common voltage node at which a common voltage occurs and the set terminal. When the output of the latch circuit is high, the first switch is turned on. A second switch is arranged between the common voltage node and the reset terminal. When the output of the latch circuit is low, the second switch is turned on.

A primary transmitter drives a primary-side input of an isolation barrier in response to a transition of an input signal. A secondary receiver generates an output signal having a logical value that corresponds to a signal that occurs at a secondary-side output of the isolation barrier. A secondary transmitter drives a secondary-side input of the isolation barrier based on the output signal. A primary receiver generates a return signal having a logical value that corresponds to a signal that occurs at a primary-side output of the isolation barrier. The primary transmitter repeatedly drives the primary-side input of the isolation barrier until the logical value of the input signal matches that of the return signal.

An output circuit includes a comparator circuit, a voltage conversion circuit and a signal output circuit. The comparator circuit detects an operating mode based on a first supply voltage and a second supply voltage and generates a first control signal. The voltage conversion circuit adjusts a level of an output voltage from a low-dropout regulator according to the first control signal to generate a first voltage, and generates a second voltage according to the first control signal and the first voltage. The signal output circuit adjusts a level of a digital signal according to the first voltage, the second voltage and the first supply voltage to generate a digital output signal corresponding to the operating mode.

A device including an inverter circuit, a hysteresis control circuit, and a high-side input level shifter. The inverter circuit having an output and including at least two series connected PMOS transistors connected, at the output, in series to at least two series connected NMOS transistors. The hysteresis control circuit coupled to the output to provide feedback to the at least two series connected PMOS transistors and to the at least two series connected NMOS transistors. The high-side input level shifter connected to gates of the at least two PMOS transistors and configured to shift a low level of an input signal to a higher level and provide the higher level to one or more of the gates of the at least two PMOS transistors.

The present invention provides a frequency-halving latch circuit for deterministic field bus network data forwarding and application thereof. The frequency-halving latch circuit includes a data buffer equipped with two buffer units; a frequency-halving enable latch signal generation module for generating a first frequency-halving latch signal and a second frequency-halving latch signal with opposite levels, and selecting data buffer units of the data buffer based on the first frequency-halving latch signal, the second frequency-halving latch signal and a receiving enable signal; and a shift register including a first trigger and a second trigger which are initialized to opposite output states, the first trigger and the second trigger is connected to realize a shift operation, and data stored in the data buffer units is finally selected and read based on a low order in the shift register composed of the two triggers and a read enable signal. The frequency-halving latch circuit can be applied to a scenario of deterministic field bus network data forwarding as a same-frequency out-of-phase data cross-clock domain circuit, with high resource utilization rate and stability.

In described examples, an integrated circuit includes an on-off keying (OOK) digital isolator, which includes a first circuitry, a multiplexer, an OOK modulator, an isolation barrier, an OOK envelope detector, and a second circuitry. The first circuitry generates and outputs a calibration signal. The multiplexer has a data signal input, and an input coupled to a first circuitry output. An OOK modulator input is coupled to a multiplexer output. An isolation barrier input is coupled to an OOK modulator output. An OOK envelope detector input is coupled to an isolation barrier output. The second circuitry includes an input coupled to an OOK envelope detector output, and an output coupled to an OOK envelope detector control input. The second circuitry detects a duty cycle distortion (DCD) of the OOK envelope detector output, and outputs a control signal to change the OOK envelope detector output's duty cycle based on the detected DCD.

A microcontroller includes an input pin and internal pull-up and pull-down circuits. External pull-up and pull-down circuits are also coupled to the input pin. The microcontroller is operable according to different configuration modes which include configuring the input pin in a floating state. A control logic then configures the internal pull-up and pull-down circuits according to an internal pull-up mode to acquire a first input voltage signal (at a first logic value) from the input pin, and further configure the internal pull-up and pull-down circuits according to an internal pull-down mode to acquire a second input voltage signal (at a second logic value) from the input pin. A selection of the operating mode of the MCU is then made based on the acquired first and second logic values.

A microcontroller includes an input pin and internal pull-up and pull-down circuits. External pull-up and pull-down circuits are also coupled to the input pin. The microcontroller is operable according to different configuration modes which include configuring the input pin in a floating state. A control logic then configures the internal pull-up and pull-down circuits according to an internal pull-up mode to acquire a first input voltage signal (at a first logic value) from the input pin, and further configure the internal pull-up and pull-down circuits according to an internal pull-down mode to acquire a second input voltage signal (at a second logic value) from the input pin. A selection of the operating mode of the MCU is then made based on the acquired first and second logic values.