Electromagnetic interference reducing circuit

Patent metadata

Field	Value
Publication number	US-11545894-B2
Application number	US-202117191932-A
Country	US
Kind code	B2
Filing date	Mar 4, 2021
Priority date	Oct 12, 2020
Publication date	Jan 3, 2023
Grant date	Jan 3, 2023

Abstract

An electromagnetic interference reducing circuit is provided. A first random number generator generates a plurality of first random number signals each having a plurality of triangular waves. Each of the triangular waves has a plurality of steps. The first random number generator generates a plurality of first random numbers and modulates each of the first random number signals according to the first random numbers. The first random number generator repeatedly counts, repeatedly removes, or does not count time of the steps of each of the triangular waves of each of the first random number signals according to one of the first random numbers. A first oscillator generates a first oscillating signal. A motor controller circuit controls a plurality of switch components of a motor respectively according to the first random number signals based on the first oscillating signal.

First claim

What is claimed is:

1. An electromagnetic interference reducing circuit of a motor, wherein the motor is connected to a motor driver circuit, and the motor driver circuit includes a plurality of switch components connected to the motor, the electromagnetic interference reducing circuit comprising:
a first oscillator configured to generate a first oscillating signal;
a first random number generator configured to generate a plurality of first random number signals each having a plurality of triangular waves, wherein each of the triangular waves has a plurality of steps, and the first random number generator is configured to generate a plurality of first random numbers; wherein each time when a first clock signal reaches a reference level, the first random number generator modulates one of the triangular waves of each of the first random number signals according to one of the first random numbers; wherein the first random number generator repeatedly counts, repeatedly removes, or does not count time of the steps of each of the triangular waves of each of the first random number signals according to one of the first random numbers, such that each one of periods of the first random number signal is adjusted to be not equal to a next one of the periods of the first random number signal, and a number of the steps of each of the triangular waves that are repeatedly counted, repeatedly removed or not counted depends on the one first random number of each of the triangular waves; and
a motor controller circuit connected to the first oscillator and the first random number generator, configured to receive the first oscillating signal from the first oscillator and output the first clock signal to the first random number generator, and configured to control the switch components respectively according to the first random number signals based on the first oscillating signal.

2. The electromagnetic interference reducing circuit according to claim 1 , wherein, when a previous one of the triangular waves of each of the first random number signals falls to a valley value, the first random number generator generates the first random number of a next one of the triangular waves, and modulates a rising wave segment and a falling wave segment of the next one triangular wave of each of the first random number signals according to the first random number of the next one triangular wave.

3. The electromagnetic interference reducing circuit according to claim 1 , wherein, when a rising wave segment of a previous one of the triangular waves of each of the first random number signals rises to a peak value, the first random number generator generates one of the first random numbers, and modulates a falling wave segment of the previous one of the triangular waves and a rising wave segment of a next one of the triangular waves of each of the first random number signals according to the one of the first random numbers.

4. The electromagnetic interference reducing circuit according to claim 1 , wherein the motor driver circuit further includes a plurality of phase controller circuits, the phase controller circuits are connected to the motor controller circuit and are respectively connected to the plurality of switch components, and the motor controller circuit controls the phase controller circuits respectively to adjust phases of signals inputted to the motor through the switch components according to the first random number signals.

5. The electromagnetic interference reducing circuit according to claim 4 , wherein the phase controller circuit includes a plurality of first phase controller circuits and a plurality of second phase controller circuits, the switch components include a plurality of high-side switches and a plurality of low-side switches, the hide-side switches are p-type metal oxide semiconductor (PMOS) field effect transistors and are respectively connected to the first phase controller circuits, and the low-side switches are n-type metal oxide semiconductor (NMOS) field effect transistors and are respectively connected to the second phase controller circuits.

6. The electromagnetic interference reducing circuit according to claim 5 , wherein the phase controller circuit includes a plurality of first phase controller circuits and a plurality of second phase controller circuits, the switch components include a plurality of hide-side switches and a plurality of low-side switches, the hide-side switches are n-type metal oxide semiconductor field effect transistors and are respectively connected to the first phase controller circuits, and the low-side switches are n-type metal oxide semiconductor field effect transistors and are respectively connected to the second phase controller circuits.

7. The electromagnetic interference reducing circuit according to claim 6 , further comprising:
a second random number generator, a second oscillator and a charging pump, wherein the second oscillator is connected to the second random number generator and the charging pump, the charging pump is connected to the first phase controller circuits, and the second oscillator outputs a second oscillating signal; wherein each time when the second oscillating signal reaches a reference level, the second random number generator generates a plurality of second random numbers and outputs a plurality of second random number signals respectively according to the second random numbers; wherein the second oscillator modulates the second oscillating signal according to the second random number signals, and the charging pump outputs a power signal to the motor sequentially through each of the first phase controller circuits and the high-side switches according to the second oscillating signal.

8. The electromagnetic interference reducing circuit according to claim 7 , wherein the second oscillator includes a first transistor, a second transistor, a comparator, a reference voltage circuit, a first modulator circuit, a second modulator circuit and a third modulator circuit; wherein a first terminal of the first transistor and a second terminal of the first transistor are respectively connected to the first modulator circuit and a first terminal of the second transistor, the second random number generator is connected to the first modulator circuit, the second modulator circuit and the third modulator circuit, and the second random number generator outputs the second random number signals for simultaneously controlling the first modulator circuit, the second modulator circuit or the third modulator circuit;
wherein a first input terminal of the comparator is connected to the first terminal of the second transistor and the second modulator circuit, a second input terminal of the comparator and an output terminal of the comparator are connected to the reference voltage circuit, and the reference voltage circuit outputs a reference voltage to the second input terminal of the comparator according to the second oscillating signal outputted by the comparator; wherein the output terminal of the comparator is connected to a control terminal of the first transistor, a control terminal of the second transistor, the second random number generator and the charging pump, and the comparator outputs the second oscillating signal to the first transistor, the second transistor, the second random number generator and the charging pump.

9. The electromagnetic interference reducing circuit according to claim 8 , wherein the first modulator circuit includes a plurality of first current sources and a plurality of first switches, the first current sources are respectively connected to first terminals of the first switches, a second terminal and a control terminal of each of the first switches are respectively connected to the first te

Assignees

• Anpec Electronics Corp

Inventors

• Chen Li-Wei

Classifications

• H02P7/00 Primary

  Arrangements for regulating or controlling the speed or torque of electric DC motors · CPC title

• H01R4/64

  Connections between or with conductive parts having primarily a non-electric function, e.g. frame, casing, rail · CPC title

• H03K3/84

  Generating pulses having a predetermined statistical distribution of a parameter, e.g. random pulse generators · CPC title

• H02P6/26

  Arrangements for controlling single phase motors · CPC title

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title