Digital pulse width controlled oscillation modulator
AssigneeBang & Olufsen Icepower A/S
InventorOle Neis Nielsen
Life of this patent
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Abstract
A pulse width modulator (10) for converting a digital signal into a PWM signal, comprising a plurality of integrators (11) with integrator gains (12) arranged in series, a comparator (17) for comparing the output of the last integrator (11′) with a reference, and thereby creating the PWM signal. The modulator further has means (13) for realizing self-oscillation at a desired switching frequency, and a feedback path (14) connected to a point down stream said comparator and leading to a plurality of summing points, each preceding one of said integrators, wherein the PWM signal is quantized in time by the clock frequency of the modulator, and wherein the integrator gains (12) are adapted to reduce any quantization noise.
Claims23
A pulse width modulator for converting a digital signal into a PWM signal, comprising:
- a plurality of integrators with integrator gains arranged in series,
- a comparator for comparing the output of the last integrator with a reference, and thereby creating the PWM signal,
- means for realizing self-oscillation at a desired switching frequency, and
- a feedback path connected to a point down stream said comparator and leading to a plurality of summing points, each preceding one of said integrators,
- wherein the PWM signal is quantized in time by a clock frequency of the modulator,
- wherein the integrator gains are adapted to reduce any quantization noise, and
- wherein said desired switching frequency is significantly lower than said clock frequency.
A pulse width modulator for converting a digital signal into a PWM signal, comprising:
- a plurality of integrators with integrator gains arranged in series,
- a comparator for comparing the output of the last integrator with a reference, and thereby creating the PWM signal, and
- means for realizing self-oscillation at a desired switching frequency, and
- a feedback path connected to a point down stream said comparator and leading to a plurality of summing points, each preceding one of said integrators,
- wherein the PWM signal is quantized in time by a clock frequency of the modulator,
- wherein the integrator gains are adapted to reduce any quantization noise, and
- wherein the means for self-oscillation includes a positive feedback of the comparator.
A pulse width modulator for converting a digital signal into a PWM signal, comprising:
- a plurality of integrators with integrator gains arranged in series,
- a comparator for comparing the output of the last integrator with a reference, and thereby creating the PWM signal,
- means for realizing self-oscillation at a desired switching frequency, and
- a feedback path connected to a point down stream said comparator and leading to a plurality of summing points, each preceding one of said integrators,
- wherein the PWM signal is quantized in time by a clock frequency of the modulator,
- wherein the integrator gains are adapted to reduce any quantization noise, and
- wherein the means for self-oscillation includes a filter or time delay, said filter or time delay being arranged to give the system an open loop phase lag of 180 degrees at the desired switching frequency.
The system according to 20, wherein the feedback path is connected to the output of the switching stage.
The system according to 20, wherein the feedback path is connected to the output of the output filter.
The system according to 20, implemented as a DC-AC converter for audio use or transmission line drivers.
Dependencies are inferred from the claim text.