KR-20260066515-A - SPREAD-SPECTRUM OSCILLATOR

KR20260066515AKR 20260066515 AKR20260066515 AKR 20260066515AKR-20260066515-A

Abstract

A spread spectrum oscillator is introduced, comprising: a current mirror circuit including a reference current terminal and an output current terminal according to one embodiment of the present invention; an oscillator connected to the output current terminal and outputting a clock signal based on the capacitor voltage of a capacitor charged by the output current of the output current terminal; a first modulation unit connected to the reference current terminal and modulating the reference current of the reference current terminal based on spread spectrum modulation data for the clock signal; a signal processing unit outputting at least one modulated clock signal that modulates the frequency of the clock signal based on the clock signal; and a second modulation unit connected to the reference current terminal and adjusting the reference current in response to a change in the frequency of the clock signal based on the spread spectrum modulation data and the modulated clock signal.

Inventors

이수호
서희택
최윤호
유민재
정보윤

Assignees

현대모비스 주식회사

Dates

Publication Date: 20260512
Application Date: 20241104

Claims (11)

A current mirror circuit including a reference current terminal and an output current terminal; An oscillator connected to the output current terminal and outputting a clock signal based on the capacitor voltage of a capacitor charged by the output current of the output current terminal; A first modulation unit connected to the reference current terminal and modulating the reference current of the reference current terminal based on spread spectrum modulation data for the clock signal; A signal processing unit that outputs at least one modulated clock signal that modulates the frequency of the clock signal based on the clock signal; and A spread spectrum oscillator comprising a second modulation unit connected to the reference current unit and adjusting the reference current in response to a change in the frequency of the clock signal based on the spread spectrum modulation data and the modulation clock signal.
In Article 1, The above second modulation unit is, A spread spectrum oscillator that adjusts the reference current to increase when the frequency of the clock signal increases.
In Article 1, The above signal processing unit is, A spread spectrum oscillator comprising a plurality of frequency dividers, wherein one of the plurality of frequency dividers has the clock signal as an input and at least some have the output of another frequency divider as an input.
In Paragraph 3, The above plurality of frequency dividers A spread spectrum oscillator that outputs a signal having a frequency of the value obtained by dividing each input signal by a preset value.
In Article 1, The above second modulation unit is, A current source connected to the above reference current terminal and outputting a current at a preset ratio with respect to the above reference current; A first switching unit that switches based on the spread spectrum modulation data above; and A spread spectrum oscillator comprising a second switching unit that switches based on the modulation clock signal.
In Article 5, The ratio set above is, A spread spectrum oscillator in which the current output from the above current source is set to be smaller than the above reference current.
In Article 5, The above spread spectrum modulation data is, It consists of an N-bit digital signal, and The above modulation clock signal is, A spread spectrum oscillator composed of N modulation clock signals having different frequencies.
In Article 7, The first switching unit above is, It includes a switching element corresponding to each bit number of the spread spectrum modulation data above, The above second switching unit is, A spread spectrum oscillator comprising a switching element corresponding to each of the N modulation clock signals.
In Article 1, The above oscillator is, Includes capacitors and comparators, The above comparator is, A spread spectrum oscillator that compares the voltage of the capacitor charged based on the output current with a reference voltage, and outputs a clock signal in a high state when the voltage of the capacitor is greater than the reference voltage, and in a low state when the voltage of the capacitor is less than or equal to the reference voltage.
In Article 9, A spread spectrum oscillator further comprising a third modulation unit connected to the output current terminal and the capacitor, which modulates the discharge current that discharges the capacitor when the frequency of the clock signal increases, based on the clock signal and the modulation clock signal.
In Article 10, The above third modulation unit is, A current source connected to the above reference current terminal and outputting a current at a preset ratio with respect to the above reference current; A third switching unit that switches based on the above clock signal; and A spread spectrum oscillator comprising a fourth switching unit that switches based on the above modulation clock signal.

Description

Spread-Spectrum Oscillator The present invention relates to a spread spectrum oscillator that modulates the frequency of a clock signal. An oscillator can generate a clock signal that oscillates at a specific period by performing switching operations at a specific frequency. In this case, strong Electromagnetic Interference (EMI) noise can be generated in the frequency band where the switching is performed. EMI noise concentrated in this switching frequency band can cause malfunctions in peripheral devices of the oscillator. Here, Spread Spectrum Frequency Modulation (SPMP) is being studied as a method to reduce EMI noise that occurs intensively in the switching frequency band by modulating the switching frequency to disperse the switching frequency band. The matters described above as background technology are intended only to enhance understanding of the background of the present invention and should not be construed as an acknowledgment that they constitute prior art already known to those skilled in the art. FIGS. 1 and FIGS. 2 are drawings for illustrating a diffuse spectrum oscillator according to an embodiment of the present invention. FIG. 3 is a circuit diagram for explaining a second modulation unit and a signal processing unit according to an embodiment of the present invention. FIG. 4 is a circuit diagram of a spread spectrum oscillator including a third modulation unit according to one embodiment of the present invention. Figure 5 is a graph illustrating spread spectrum modulation according to the triangular modulation technique. FIGS. 6 and FIGS. 7 are graphs for explaining spread spectrum modulation according to a random modulation technique according to an embodiment of the present invention. FIGS. 8 to 10 are graphs for comparing the energy peak values of a clock signal according to an embodiment of the present invention. Specific structural or functional descriptions of the embodiments of the present invention disclosed in this specification or application are merely illustrative for the purpose of explaining embodiments according to the present invention, and embodiments according to the present invention may be implemented in various forms and should not be interpreted as being limited to the embodiments described in this specification or application. Since embodiments according to the present invention may be subject to various modifications and may take various forms, specific embodiments are illustrated in the drawings and described in detail in this specification or application. However, this is not intended to limit embodiments according to the concept of the present invention to specific disclosed forms, and it should be understood that they include all modifications, equivalents, and substitutions that fall within the spirit and scope of the present invention. Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which the present invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this specification. Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components regardless of drawing symbols are given the same reference number, and redundant descriptions thereof will be omitted. In the description of the following embodiments, the term "pre-set" means that the numerical value of a parameter is predetermined when the parameter is used in a process or algorithm. Depending on the embodiment, the numerical value of the parameter may be set when the process or algorithm starts or during the period in which the process or algorithm is executed. The suffixes "module" and "part" used for components in the following description are assigned or used interchangeably solely for the ease of drafting the specification, and do not inherently possess distinct meanings or roles. In describing the embodiments disclosed in this specification, if it is determined that a detailed description of related prior art may obscure the essence of the embodiments disclosed in this specification, such detailed description is omitted. Furthermore, the attached drawings are intended only to facilitate understanding of the embodiments disclosed in this specification, and the technical concept disclosed in this specification is not limited by the attached drawings; it should be understood that they include all modifications, equivalents, and substitutions that fall within the spirit and technical scope of the present invention. Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said term