US 2011/0032008 A1 · PULSE WIDTH MODULATION FREQUENCY CONVERSION

Abstract

A pulse width modulation (PWM) frequency converter converts an input PWM signal to an output PWM signal having a different frequency while maintaining a substantially equal duty ratio. The PWM frequency converter samples the input PWM signal for a PWM cycle using a sampling clock. A filter module filters the resulting set of one or more PWM parameters to compensate for noise introduced by potential clock mismatch, clock jitter, ambient variations, and other non-deterministic issues, thereby generating filtered PWM parameters. The sampling employed by the filter module compares a difference between the one or more current PWM parameters and previous (or historical) PWM parameters from an earlier sampled PWM cycle to a predetermined change threshold in determining a filtered set of one or more PWM parameters. The filtered set of one or more PWM parameters then is used to generate one or more corresponding PWM cycles of the output signal.

Claims20

Dependent claims

In a pulse width modulation (PWM) frequency converter that receives a first PWM signal and outputs a second PWM signal having a different frequency than the first PWM signal, a method comprising:

sampling a first PWM cycle of the first PWM signal to generate a first set of one or more PWM parameters;
filtering the first set of one or more PWM parameters based on a predetermined change threshold to generate a second set of one or more PWM parameters;
and
generating a second PWM cycle for the second PWM signal based on the second set of one or more PWM parameters.

1 more element

A pulse width modulation (PWM) frequency converter having an input to receive a first PWM signal and an output to provide a second PWM signal having a different frequency than the first PWM signal, the PWM frequency converter comprising:

a sampling module to sample a first PWM cycle of the first PWM signal to generate a first set of one or more PWM parameters;
a filter module to filter the first set of one or more PWM parameters based on a predetermined change threshold to generate a second set of one or more PWM parameters;
and
a PWM generator module to generate a second PWM cycle for the second PWM signal based on the second set of one or more PWM parameters.

1 more element

In a pulse width modulation (PWM) frequency converter that receives a first PWM signal and outputs a second PWM signal having a higher frequency than the first PWM signal, a method comprising:

sampling a first PWM cycle of the first PWM signal to determine a first value and a second value, the first value representative of a number of samples having a select sample value for the first PWM cycle and the second value representative of a total number of samples for the first PWM cycle;
sampling a second PWM cycle of the first PWM signal that occurs subsequent to the first PWM cycle to determine a third value and a fourth value, the third value representative of a number of samples having the select sample value for the second PWM cycle and the fourth value representative of a total number of samples for the second PWM cycle;
filtering the third value based on the first value and a predetermined change threshold to generate a fifth value;
filtering the fourth value based on the second value and the predetermined change threshold to generate a sixth value;
and
generating a PWM cycle of the second PWM signal based on the fifth value and the sixth value.

3 more elements

Dependencies are inferred from the claim text.

Pulse width modulation frequency conversion

Life of this patent

Pulse width modulation frequency conversion

Life of this patent

Abstract

Claims20