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US 2018/0323774 A1Published application
PWM Modulator
AssigneeSTMicroelectronics S.r.l.
InventorsMarco Raimondi, Edoardo Botti
Life of this patent
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Abstract
A method is for reducing pulse skipping from a characteristic affecting a modulating signal input to an integrator of a pulse width modulation (PWM) modulator, together with a square wave carrier signal for generating a triangular waveform of the PWM modulator. The method may include creating a broad synchronous peak at vertexes of the triangular waveform output by the integrator.
Claims20
A pulse width modulation (PWM) modulator, comprising:
- an integrator configured to:
- receive a modulating signal and a square wave carrier signal;
- modulate the square wave carrier signal based on the modulating signal, the square wave carrier signal having a frequency greater than a frequency of the modulating signal;
- and
- output a triangular waveform comprising a downward slope, an upward slope, and a step discontinuity connecting an end of the downward slope to a beginning of the upward slope;
- and
- a comparator configured to compare the triangular waveform with a threshold and output a PWM modulated square wave carrier signal, wherein the integrator comprises a negative feedback loop coupled between an output of the integrator and an input terminal of the integrator, the negative feedback loop comprising:
- an integrating capacitor;
- and
- a resistor coupled in series with the integrating capacitor, the resistor having a resistance configured to cancel a right hand side zero of a transfer function of the integrator.
7 more elements
A pulse width modulation (PWM) modulator, comprising:
- an operational amplifier comprising a first input terminal, a second input terminal, and an output terminal;
- a capacitive element having a first terminal tied to the first input terminal;
- a resistive element having a first terminal tied to a second terminal of the capacitive element, the resistive element further having a second terminal tied to the output terminal of the operational amplifier;
- a carrier signal generator configured to generate a carrier signal, wherein the first input terminal of the operational amplifier is configured to receive the carrier signal;
- a modulator configured to generate a modulating signal, the carrier signal having a frequency greater than a frequency of the modulating signal, wherein the first input terminal of the operational amplifier is configured to receive the modulating signal, and wherein the output terminal of the operational amplifier is configured to generate a triangular waveform;
- and
- a comparator configured to compare the triangular waveform with a threshold and output a PWM modulated carrier signal.
4 more elements
A method, comprising:
- generating, across a capacitive element coupled between an output of an operational amplifier and an input terminal of the operational amplifier, a triangle waveform based on a square wave carrier signal and a modulating signal received at the input terminal of the operational amplifier;
- generating, across a resistive element coupled between the output of the operational amplifier and the input terminal of the operational amplifier, a square-wave signal that tracks a waveform of the square wave carrier signal;
- and
- generating a synchronous peak at one or more vertexes of the triangle waveform to form a triangular waveform comprising a downward slope, an upward slope, and a step discontinuity connecting an end of the downward slope to a beginning of the upward slope.
1 more element
Dependencies are inferred from the claim text.