An apparatus for transmitting a bit in addition to a plurality of payload data symbols of a communication protocol is provided. The apparatus comprises an input interface configured to receive information about a bit value of the bit. Further, the apparatus comprises a transmission circuit configured to, if the bit value is a first value, transmit the plurality of payload data symbols at predetermined positions in a data signal as pulses of variable pulse length. The respective pulse length of each of the pulses is selected based on the symbol value of the payload data symbol represented by the respective pulse. If the bit value is a second value, the transmission circuit is configured to transmit a pulse exhibiting a pulse length being longer than a maximum payload data symbol pulse length defined in the communication protocol at the predetermined position of the pulse for the d-th payload data symbol of the plurality of payload data symbols, d=k+i if k+iz. d=([k+i] mod z) if k+i>z. k is the symbol value of the i-th payload data symbol of the plurality of payload data symbols, z is the number of possible symbol values of the payload data symbols defined in the communication protocol, and 1iz.

A receiver for demodulating a pulse width modulated (PWM) signal, comprises: a voltage level shifter for shifting the PWM signal to predefined transistor voltage levels; a half-rate PWM decoder for receiving the shifted PWM signal; and a 2-bit-to-N-bit deserializer. The half-rate PWM decoder comprises a first decoder core, a second decoder core, a controller, and a sampler and retiming circuit. The first decoder core and the second decoder core are configured to decode alternating periods of the shifted PWM signal. The controller is coupled to the first decoder core, the second decoder core, the sampler and retiming circuit. The retiming circuit is configured to receive clock signals from the controller and to output half-rate even data from the first decoder core and half-rate odd data from the second decoder core. Outputs of the retiming circuit and an output of the controller are coupled to inputs of the deserializer.

A receiver for demodulating a pulse width modulated (PWM) signal, comprises: a voltage level shifter for shifting the PWM signal to predefined transistor voltage levels; a half-rate PWM decoder for receiving the shifted PWM signal; and a 2-bit-to-N-bit deserializer. The half-rate PWM decoder comprises a first decoder core, a second decoder core, a controller, and a sampler and retiming circuit. The first decoder core and the second decoder core are configured to decode alternating periods of the shifted PWM signal. The controller is coupled to the first decoder core, the second decoder core, the sampler and retiming circuit. The retiming circuit is configured to receive clock signals from the controller and to output half-rate even data from the first decoder core and half-rate odd data from the second decoder core. Outputs of the retiming circuit and an output of the controller are coupled to inputs of the deserializer.

A receiver for demodulating a pulse width modulated (PWM) signal, comprises: a voltage level shifter for shifting the PWM signal to predefined transistor voltage levels; a half-rate PWM decoder for receiving the shifted PWM signal; and a 2-bit-to-N-bit deserializer. The half-rate PWM decoder comprises a first decoder core, a second decoder core, a controller, and a sampler and retiming circuit. The first decoder core and the second decoder core are configured to decode alternating periods of the shifted PWM signal. The controller is coupled to the first decoder core, the second decoder core, the sampler and retiming circuit. The retiming circuit is configured to receive clock signals from the controller and to output half-rate even data from the first decoder core and half-rate odd data from the second decoder core. Outputs of the retiming circuit and an output of the controller are coupled to inputs of the deserializer.

A receiver for demodulating a pulse width modulated (PWM) signal, comprises: a voltage level shifter for shifting the PWM signal to predefined transistor voltage levels; a half-rate PWM decoder for receiving the shifted PWM signal; and a 2-bit-to-N-bit deserializer. The half-rate PWM decoder comprises a first decoder core, a second decoder core, a controller, and a sampler and retiming circuit. The first decoder core and the second decoder core are configured to decode alternating periods of the shifted PWM signal. The controller is coupled to the first decoder core, the second decoder core, the sampler and retiming circuit. The retiming circuit is configured to receive clock signals from the controller and to output half-rate even data from the first decoder core and half-rate odd data from the second decoder core. Outputs of the retiming circuit and an output of the controller are coupled to inputs of the deserializer.

A circuit for decoding a pulse width modulated (PWM) signal generates an output signal switching between a first and second logic values as a function of a duty-cycle of the PWM signal. Current generating circuitry receives the PWM signal and injects a current to and sinks a current from an intermediate node as a function of the values of the PWM signal. A capacitor coupled to the intermediate node is alternatively charged and discharged by the injected and sunk currents, respectively, to generate a voltage. A comparator circuit coupled to the intermediate node compares the generated voltage to a comparison voltage and drives the logic values of the output signal as a function of the comparison.

A circuit for decoding a pulse width modulated (PWM) signal generates an output signal switching between a first and second logic values as a function of a duty-cycle of the PWM signal. Current generating circuitry receives the PWM signal and injects a current to and sinks a current from an intermediate node as a function of the values of the PWM signal. A capacitor coupled to the intermediate node is alternatively charged and discharged by the injected and sunk currents, respectively, to generate a voltage. A comparator circuit coupled to the intermediate node compares the generated voltage to a comparison voltage and drives the logic values of the output signal as a function of the comparison.

Systems and methods for phase demodulation is described. A wireless power transmitter can include a controller, a transmission coil, and an integrated circuit connected to the controller and the transmission coil. The integrated circuit can be configured to measure a voltage of a transmission coil of a wireless power transmitter. The integrated circuit can be further configured to generate, based on the measured voltage, a pulse signal comprising a plurality of pulses. The integrated circuit can be further configured to send the pulse signal to the controller of the wireless power transmitter. The controller can be configured to perform phase demodulation using the pulse signal.

An oscillator including two sequentially connected pulse generation circuits is disclosed. Each pulse generation circuit includes a charge/discharge circuit and a switch circuit and outputs a first or second signal depending on an input signal. The switch circuit controls the charge/discharge circuit so that the latter is charged when the input signal is at a first level and discharged when the input signal is at a second level higher than the first level. When the input signal is at the first level, the first signal is at the first level and the second signal is at the second level. When the input signal is at the second level, the first signal is at the second level and the second signal is at the first level. Upon completion of discharge of the charge/discharge circuit, the first signal changes to the first level and the second signal changes to the second level.

An oscillator including two sequentially connected pulse generation circuits is disclosed. Each pulse generation circuit includes a charge/discharge circuit and a switch circuit and outputs a first or second signal depending on an input signal. The switch circuit controls the charge/discharge circuit so that the latter is charged when the input signal is at a first level and discharged when the input signal is at a second level higher than the first level. When the input signal is at the first level, the first signal is at the first level and the second signal is at the second level. When the input signal is at the second level, the first signal is at the second level and the second signal is at the first level. Upon completion of discharge of the charge/discharge circuit, the first signal changes to the first level and the second signal changes to the second level.