Enhanced hybrid class-S modulator

A method for amplitude modulating a power supply voltage signal, comprising:

• receiving a sequence of N-bit digital words, where N is a positive integer;
• generating a series of pulse-width modulated (PWM) signals based on the K most significant bits (MSBs) of the N-bit digital words, where K is a positive integer and N>K;
• modulating a power supply voltage signal based on the PWM signals, to provide a modulated power supply voltage signal;
• and
• reducing quantization errors present in the modulated power supply voltage signal.

A modulator circuit, comprising:

• a pulse-width modulator configured to receive the K most significant bits (MSBs) of a sequence of N-bit digital words, where N and K are positive integers and N>K, and provide a series of pulse-width modulated signals;
• a buck converter configured to receive a power supply voltage signal and said pulse-width modulated signals, said buck converter operable to provide a quantized amplitude modulated power supply voltage signal;
• and
• a quantization error correction circuit coupled to the buck converter, said quantization error correction circuit operable to source or sink current into or out of an output node of the buck converter when magnitudes of the modulated power supply voltage signal are greater than or less than desired magnitudes defined by the N-bit digital words.

A modulator circuit, comprising:

• means for generating a series of pulse-width modulated (PWM) signals based on the K most significant bits (MSBs) of a sequence of N-bit digital words, where K and N are positive integers and N>K;
• means for modulating a power supply voltage signal based on the PWM signals, to provide a modulated power supply voltage signal;
• and
• means for reducing quantization errors present in the modulated power supply voltage signal.

A modulator circuit, comprising:

• an input port conflgured to receive a succession of N-bit digital words, where N is an integer that is greater than one;
• a modulator operable to modulate a power supply voltage according to values represented by the K most significant bits of each N-bit digital word, where K is a positive integer that is less than N;
• an output port adapted to provide amodulated power supply voltage signal;
• and
• a circuit coupled to said modulator,, said circuit operable to reduce deviations of voltage levels of the modulated power supply voltage signal from desired voltage levels.

A modulator circuit, comprising:

• an input node configured to receive an input signal;
• a modulator having an input configured to receive an approximated input signal and modulate a power supply voltage according to the approximated input signal to generate a modulated power supply voltage signal;
• and
• a correction circuit having a first input operable to reduce an error in the modulated power supply voltage caused by modulating the power supply voltage according to the approximated input signal.

A polar modulator circuit, comprising:

• a modulator having an input configured to receive amplitude, information of an information signal and generate a modulated power supply voltage signal according to the amplitude information;
• a circuit coupled to the modulator, said circuit operable to reduce the degree by which voltage levels of the modulated power supply voltage signal deviate from desired voltage levels;
• and
• a radio frequency power amplifier (R.FPA) having a drive input configured to receive constant-amplitude phase modulated information of said information signal, a power setting input terminal configured to receive the modulated power supply voltage signal, and an output node adapted to provide a modulated RF carrier.

A poiar modulation method, comprising:

• modulating a power supply voltage according to amplitude information of an information signal to generate a modulated-power supply voltage signal;
• reducing the degree by which voltage levels of the modulated power supply voltage signal deviate from desired voltage levels;
• generating a radio frequency signal from a constant-amplitude, phase-modulated signal;
• and
• amplifying and varying the amplitude of the radio frequency signal according to said modulated power supply voltage signal.