US 8,013,677 B2 · One-sided switching pulse width modulation amplifiers

Abstract

One-sided pulse width modulated (PWM) amplifiers are disclosed. An example amplifier includes an integrator to receive first and second analog signals, and to output a first amplified signal and a second amplified signal based on the first and second analog signals, a reference changer coupled to the integrator to determine whether a first amplitude is higher than a second amplitude based on the first and second analog signals, to selectively cause the integrator to apply a first resistance between a reference node and the first amplified signal and apply a second resistance between the reference node and the second amplified signal when the first amplitude is higher than the second amplitude, and to selectively cause the integrator to apply the second resistance between the reference node and the first amplified signal and apply the first resistance between the reference node and the second amplified signal when the second amplitude is higher than the first amplitude, and first and second comparators coupled to the integrator to receive the first and second amplified signals, to compare the first and second amplified signals to a reference signal, and to output first and second pulse width modulated signals having respective first and second pulse widths based on the comparisons between the first and second amplified signals and the reference signal.

Claims26

Dependent claims

An apparatus comprising:

an integrator that is configured to receive first and second analog signals and to output a first amplified signal and a second amplified signal based at least in part on the first and second analog signals wherein the integrator includes a reference changer that determines whether a first amplitude is higher than a second amplitude based at least in part on the first and second analog signals, and wherein the reference changer selectively applies a first resistance between a reference node and a first output node that receives the first amplified signal and selectively applies a second resistance between the reference node and a second output node that receives the second amplified signal when the first amplitude is higher than the second amplitude, and wherein the reference changer selectively applies the second resistance between the reference node and the first output node and selectively applies the first resistance between the reference node and the second output node when the second amplitude is higher than the first amplitude;
and
first and second comparators coupled to the integrator to receive the first and second amplified signals, wherein the first and second comparators compare the first and second amplified signals to a reference signal and output first and second pulse width modulated (PWM) signals having respective first and second pulse widths based at least in part on the comparisons between the first and second amplified signals and the reference signal.

An apparatus comprising:

an integrator having differential input terminals and differential output terminals, wherein the integrator includes a reference changer, and wherein the reference changer includes:
a resistor network that is coupled between the differential output terminals of the integrator;
a comparator that is coupled to the differential output terminals of the integrator;
and
a transistor network that is coupled to and controlled by the comparator and that is coupled to the resistor network, wherein the transistor network adjusts the resistance of the resistor network in response to the comparator;
and
a PWM signal generator that is coupled to the differential output terminals of the integrator.

4 more elements

Dependencies are inferred from the claim text.

One-sided switching pulse width modulation amplifiers

Life of this patent

One-sided switching pulse width modulation amplifiers

Life of this patent

Abstract

Claims26