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US 10,483,885 B1Granted
Methods and apparatus for rotation detection of a brushed DC motor
AssigneeSemiconductor Components Industries, LLC
InventorTsutomu Murata
Life of this patent
Estimating the term…
Abstract
Various embodiments of the present technology comprise a method and apparatus for rotation detection of a brushed DC motor. The method and apparatus may detect switching of the commutators and utilize signals indicative of switching to determine speed and/or rotation information of the motor. In one embodiment, the apparatus comprises an ADC, a difference circuit, an absolute value circuit, and a comparator connected in series with each other.
Claims20
A detection circuit connected to a brushed DC motor, comprising:
- a differential amplifier configured to detect a current of the brushed DC motor and generate an analog signal that is proportional to the current;
- an analog-to-digital converter (ADC) connected to the differential amplifier and configured to convert the analog signal to a first digital signal;
- and
- a digital circuit connected to the ADC and comprising:
- a difference circuit configured to:
- receive the first digital signal;
- and
- compute a second digital signal, wherein the second digital signal is the difference of the first digital signal and a previous first digital signal;
- an absolute value circuit connected to the difference circuit and configured to compute an absolute value of the second digital signal;
- and
- a comparator circuit connected to the absolute value circuit and configured to:
- compare the computed absolute value with a predetermined threshold value;
- and
- generate a comparator output according to the comparison.
11 more elements
A method for detecting rotation information of a brushed DC motor having a plurality of commutators, comprising:
- detecting a current of the brushed DC motor;
- generating an analog signal that is proportional to the detected current;
- converting the analog signal to a first digital signal;
- computing a second digital signal, wherein the second digital signal is a difference of the first digital signal and a previous first digital signal;
- computing an absolute value of the second digital signal;
- comparing the computed absolute value with a predetermined threshold value;
- and
- generating an output according to the comparison, wherein the output represents switching from one commutator of the brushed DC motor to a different commutator.
5 more elements
A brushed DC motor system, comprising:
- a drive circuit;
- a brushed DC motor connected to and controlled by the drive circuit, wherein the brushed DC motor comprises a plurality of commutators;
- a detection circuit connected to the brushed DC motor and comprising:
- a differential amplifier configured to detect a current of the brushed DC motor and generate an analog signal that is proportional to the current;
- an analog-to-digital converter (ADC) connected to the differential amplifier and configured to convert the analog signal to a first digital signal;
- a difference circuit comprising:
- an arithmetic circuit configured to:
- receive the first digital signal;
- and
- compute a second digital signal, wherein the second digital signal is the difference of the first digital signal and a previous first digital signal;
- a register connected to the arithmetic circuit and configured to store the previous digital signal;
- an absolute value circuit connected to the difference circuit and configured to compute an absolute value of the second digital signal;
- and
- a comparator circuit connected to the absolute value circuit at a first terminal and configured to:
- compare the computed absolute value with a predetermined threshold value;
- and
- generate a comparator output according to the comparison;
- and
- a microcontroller connected to the detection circuit and configured to analyze the comparator output to determine at least one of:
- a speed of the brushed DC motor;
- and
- a total number of rotations of the brushed DC motor during a time period.
19 more elements
Dependencies are inferred from the claim text.