# US 2021/0242874 A1 · Parameter determination method and device for spread spectrum circuit, and clock spread spectrum method and device

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- Number: US 2021/0242874 A1
- Document ID: US20210242874A1
- Status: Published application
- Kind: A1
- Application number: 16/651,511
- Filed: 2019-04-23
- Published: 2021-08-05
- Earliest claimed: 2019-04-23
- Assignees: Boe Technology Group Co., Ltd.
- Applicants: Boe Technology Group Co., Ltd.
- Inventors: Yuhai MA; Xiangye WEI; Liming XIU; Yiming BAI
- Web page: https://patentgrep.com/patent/US20210242874A1

## CPC

- H03L 7/18: using a frequency divider or counter in the loop (H03L7/20, H03L7/22 take precedence)
- H03L 7/085: concerning mainly the frequency- or phase-detection arrangement including the filtering or amplification of its output signal (H03L7/10 takes precedence; circuits for comparing the phase or frequency of two mutually-independent oscillations H03D13/00)
- H03L 7/0995: {the oscillator comprising a ring oscillator}
- H03L: AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES (generation of oscillations H03B)

## Abstract

A parameter determination method for a spread spectrum circuit, a clock spread spectrum method, a parameter determination device for a spread spectrum circuit, and a clock spread spectrum device are disclosed. The parameter determination method for the spread spectrum circuit includes: obtaining a base time unit and a target frequency; determining a spread spectrum depth coefficient according to the base time unit and the target frequency; determining whether the spread spectrum depth coefficient is greater than or equal to a base spread spectrum depth coefficient; if yes, determining the spread spectrum depth coefficient as a standard spread spectrum depth coefficient and determining a standard frequency control word according to the standard spread spectrum depth coefficient; and if no, adjusting the base time unit until a corresponding spread spectrum depth coefficient corresponding to the base time unit is greater than or equal to the base spread spectrum depth coefficient.

## Claims

### Claim 1

A parameter determination method for a spread spectrum circuit, comprising:
obtaining a base time unit and a target frequency;
determining a spread spectrum depth coefficient according to the base time unit and the target frequency;
determining whether the spread spectrum depth coefficient is greater than or equal to a base spread spectrum depth coefficient;
adjusting the base time unit until a corresponding spread spectrum depth coefficient corresponding to the base time unit is greater than or equal to the base spread spectrum depth coefficient in a case where the spread spectrum depth coefficient is smaller than the base spread spectrum depth coefficient; and
determining the spread spectrum depth coefficient as a standard spread spectrum depth coefficient and determining a standard frequency control word according to the standard spread spectrum depth coefficient in a case where the spread spectrum depth coefficient is greater than or equal to the base spread spectrum depth coefficient.

### Claim 2 (depends on 1)

The parameter determination method for the spread spectrum circuit according to claim 1, wherein determining the spread spectrum depth coefficient comprises:
determining a frequency control word according to the base time unit and the target frequency, and
determining the spread spectrum depth coefficient according to the frequency control word.

### Claim 3 (depends on 2)

The parameter determination method for the spread spectrum circuit according to claim 2, wherein determining the spread spectrum depth coefficient according to the frequency control word comprises:
determining a spread spectrum manner, and
determining the spread spectrum depth coefficient according to the spread spectrum manner and the frequency control word.

### Claim 4 (depends on 3)

The parameter determination method for the spread spectrum circuit according to claim 3, wherein the spread spectrum manner comprises a boundary spread spectrum, a central spread spectrum, an up spread spectrum, or a down spread spectrum;
in a case where the spread spectrum manner is the boundary spread spectrum, the spread spectrum depth coefficient is expressed as:
δ
max
=
1
I
ad
+
0.5
;
in a case where the spread spectrum manner is the central spread spectrum, the spread spectrum depth coefficient is expressed as:
δ
max
<
2
*
(
1
-
r
a
⁢
d
)
I
a
⁢
d
+
r
a
⁢
d
,
or
⁢
⁢
δ
max
≤
2
*
r
a
⁢
d
I
a
⁢
d
+
r
a
⁢
d
;
in a case where the spread spectrum manner is the up spread spectrum, the spread spectrum depth coefficient is expressed as:
δ
max
≤
r
ad
I
ad
+
r
ad
;
and
in a case where the spread spectrum manner is the down spread spectrum, the spread spectrum depth coefficient is expressed as:
δ
max
<
1
-
r
a
⁢
d
I
a
⁢
d
+
r
a
⁢
d
,
wherein δmax represents the spread spectrum depth coefficient, Iad is an integer part of the frequency control word, and rad is a decimal part of the frequency control word.

### Claim 5 (depends on 4)

The parameter determination method for the spread spectrum circuit according to claim 4, wherein determining the standard frequency control word according to the standard spread spectrum depth coefficient comprises:
determining an integer part and a decimal part of the standard frequency control word according to the standard spread spectrum depth coefficient,
wherein the standard frequency control word is expressed as: Fr=Ir+rr, Fr represents the standard frequency control word, Ir represents the integer part of the standard frequency control word Fr, and rr represents the decimal part of the standard frequency control word Fr.

### Claim 6 (depends on 5)

The parameter determination method for the spread spectrum circuit according to claim 5, wherein in a case where the spread spectrum depth coefficient is greater than or equal to the base spread spectrum depth coefficient, and the spread spectrum depth coefficient is determined as the standard spread spectrum depth coefficient,
in a case where the spread spectrum manner is the boundary spread spectrum, the integer part of the standard frequency control word is Ir=Iad, and the decimal part of the standard frequency control word is rr=0.5; and
in a case where the spread spectrum manner is the central spread spectrum, the up spread spectrum, or the down spread spectrum, the integer part of the standard frequency control word is Ir=Iad, and the decimal part of the standard frequency control word is rr=rad.

### Claim 7 (depends on 5)

The parameter determination method for the spread spectrum circuit according to claim 5, wherein in a case where the spread spectrum depth coefficient is greater than or equal to the base spread spectrum depth coefficient, the base time unit is determined as a standard base time unit;
the standard frequency control word corresponds to a reference frequency, and the reference frequency is expressed as:
f
s
r
=
f
T
*
F
T
F
r
,
wherein ƒsr is the reference frequency, ƒT is the target frequency, and FT is the frequency control word; and
the standard frequency control word is expressed as: Fr=Ir+rr=1/(ƒsr*Δ1), and Δ1 represents the standard base time unit.

### Claim 8 (depends on 1)

A clock spread spectrum method based on the parameter determination method for the spread spectrum circuit according to claim 1, comprising:
obtaining a reference frequency control word, wherein the reference frequency control word is the standard frequency control word obtained according to the parameter determination method for the spread spectrum circuit;
determining a target frequency control word according to the reference frequency control word and a modulation parameter, wherein the target frequency control word varies discretely with time; and
generating a spread spectrum output signal after spreading spectrum according to the target frequency control word, wherein the spread spectrum output signal corresponds to the target frequency control word.

### Claim 9 (depends on 8)

The clock spread spectrum method according to claim 8, wherein the modulation parameter comprises a modulation mode and a reference spread spectrum depth coefficient, and the reference spread spectrum depth coefficient is the standard spread spectrum depth coefficient obtained according to the parameter determination method for the spread spectrum circuit; and
the target frequency control word is expressed as:
F
⁡
(
t
)
=
F
r
⁢
e
*
[
1
+
δ
r
⁢
e
2
*
M
⁡
(
t
)
]
,
wherein F(t) represents the target frequency control word, Fre represents the reference frequency control word, δre represents the reference spread spectrum depth coefficient, M(t) represents a modulation function determined according to the modulation mode, and t represents time.

### Claim 10 (depends on 9)

The clock spread spectrum method according to claim 9, wherein the modulation function is an original modulation function, and the modulation function is expressed as:
M(t)=ξ(t),
wherein ξ(t) represents the original modulation function; or,
the modulation function is a compensation modulation function after compensating for the original modulation function, and the modulation function is expressed as:
M
⁡
(
t
)
=
E
⁡
(
ξ
⁡
(
t
)
)
=
ξ
⁡
(
t
)
1
-
δ
re
2
*
ξ
⁡
(
t
)
,
or
⁢
⁢
M
⁡
(
t
)
=
E
⁡
(
ξ
⁡
(
t
)
)
=
-
ξ
⁡
(
t
)
1
+
δ
r
⁢
e
2
*
ξ
⁡
(
t
)
,
wherein E(ξ(t)) represents the compensation modulation function, and ξ(t) represents the original modulation function.

### Claim 11 (depends on 8)

The clock spread spectrum method according to claim 8, wherein the modulation parameter comprises a modulation mode, and
generating the spread spectrum output signal after spreading spectrum according to the target frequency control word comprises:
determining a reference base time unit;
determining a modulation function according to the modulation mode; and
determining the spread spectrum output signal based on the modulation function, the reference base time unit, and the target frequency control word,
wherein a spread spectrum frequency of the spread spectrum output signal is expressed as:
f
⁡
(
M
⁡
(
t
)
)
=
1
F
⁡
(
t
)
*
Δ
r
⁢
e
=
1
F
r
⁢
e
*
[
1
+
δ
r
⁢
e
2
*
M
⁡
(
t
)
]
*
Δ
r
⁢
e
=
f
r
⁢
e
1
+
δ
r
⁢
e
2
*
M
⁡
(
t
)
,
wherein ƒ(M(t)) represents the spread spectrum frequency, F(t) represents the target frequency control word,
F
⁡
(
t
)
=
F
r
⁢
e
*
[
1
+
δ
r
⁢
e
2
*
M
⁡
(
t
)
]
,
Fre represents the reference frequency control word, δre represents the reference spread spectrum depth coefficient, M(t) represents the modulation function, Δre represents the reference base time unit, and ƒre represents a frequency corresponding to the reference frequency control word.

### Claim 12 (depends on 11)

The clock spread spectrum method according to claim 11, wherein the modulation function is an original modulation function, and the modulation function is expressed as:
M(t)=ξ(t),
wherein ξ(t) represents the original modulation function; or,
the modulation function is a compensation modulation function after compensating for the original modulation function, and the modulation function is expressed as:
M
⁡
(
t
)
=
E
⁡
(
ξ
⁡
(
t
)
)
=
ξ
⁡
(
t
)
1
-
δ
re
2
*
ξ
⁡
(
t
)
,
or
⁢
⁢
M
⁡
(
t
)
=
E
⁡
(
ξ
⁡
(
t
)
)
=
-
ξ
⁡
(
t
)
1
+
δ
r
⁢
e
2
*
ξ
⁡
(
t
)
,
wherein E(ξ(t)) represents the compensation modulation function, and ξ(t) represents the original modulation function.

### Claim 13 (depends on 9)

The clock spread spectrum method according to claim 9, wherein the modulation mode comprises a triangle modulation mode, a sawtooth modulation mode, a sinusoidal modulation mode, or a random modulation mode.

### Claim 14 (depends on 8)

The clock spread spectrum method according to claim 8, wherein a maximum value Fmax of the target frequency control word and a minimum value Fmin of the target frequency control word satisfy a following formula:
0≤Fmax−Fmin<1.

### Claim 15

A parameter determination device for a spread spectrum circuit, comprising:
a memory, configured to store computer readable instructions; and
a processor, configured to execute the computer readable instructions,
wherein when the computer readable instructions are executed by the processor, the processor performs;
obtaining a base time unit and a target frequency;
determining a spread spectrum depth coefficient according to the base time unit and the target frequency;
determining whether the spread spectrum depth coefficient is greater than or equal to a base spread spectrum depth coefficient;
adjusting the base time unit until a corresponding spread spectrum depth coefficient corresponding to the base time unit is greater than or equal to the base spread spectrum depth coefficient in a case where the spread spectrum depth coefficient is smaller than the base spread spectrum depth coefficient; and
determining the spread spectrum depth coefficient as a standard spread spectrum depth coefficient and determining a standard frequency control word according to the standard spread spectrum depth coefficient in a case where the spread spectrum depth coefficient is greater than or equal to the base spread spectrum depth coefficient.

### Claim 16 (depends on 8)

A clock spread spectrum device, comprising:
a memory, configured to store computer readable instructions; and
a processor, configured to execute the computer readable instructions and perform the clock spread spectrum method according to claim 8 when the computer readable instructions are executed by the processor.

### Claim 17 (depends on 6)

The parameter determination method for the spread spectrum circuit according to claim 6, wherein in a case where the spread spectrum depth coefficient is greater than or equal to the base spread spectrum depth coefficient, the base time unit is determined as a standard base time unit;
the standard frequency control word corresponds to a reference frequency, and the reference frequency is expressed as:
f
s
r
=
f
T
*
F
T
F
r
,
wherein ƒsr is the reference frequency, ƒT is the target frequency, and FT is the frequency control word; and
the standard frequency control word is expressed as: Fr=Ir+rr=1/(ƒsr*Δ1), and Δ1 represents the standard base time unit.

### Claim 18 (depends on 2)

A clock spread spectrum method based on the parameter determination method for the spread spectrum circuit according to claim 2, comprising:
obtaining a reference frequency control word, wherein the reference frequency control word is the standard frequency control word obtained according to the parameter determination method for the spread spectrum circuit;
determining a target frequency control word according to the reference frequency control word and a modulation parameter, wherein the target frequency control word varies discretely with time; and
generating a spread spectrum output signal after spreading spectrum according to the target frequency control word, wherein the spread spectrum output signal corresponds to the target frequency control word.

### Claim 19 (depends on 18)

The clock spread spectrum method according to claim 18, wherein the modulation parameter comprises a modulation mode and a reference spread spectrum depth coefficient, and the reference spread spectrum depth coefficient is the standard spread spectrum depth coefficient obtained according to the parameter determination method for the spread spectrum circuit; and
the target frequency control word is expressed as:
F
⁡
(
t
)
=
F
r
⁢
e
*
[
1
+
δ
r
⁢
e
2
*
M
⁡
(
t
)
]
,
wherein F(t) represents the target frequency control word, Fre represents the reference frequency control word, δre represents the reference spread spectrum depth coefficient, M(t) represents a modulation function determined according to the modulation mode, and t represents time.

### Claim 20 (depends on 19)

The clock spread spectrum method according to claim 19, wherein the modulation function is an original modulation function, and the modulation function is expressed as:
M(t)=ξ(t),
wherein ξ(t) represents the original modulation function; or,
the modulation function is a compensation modulation function after compensating for the original modulation function, and the modulation function is expressed as:
M
⁡
(
t
)
=
E
⁡
(
ξ
⁡
(
t
)
)
=
ξ
⁡
(
t
)
1
-
δ
re
2
*
ξ
⁡
(
t
)
,
or
⁢
⁢
M
⁡
(
t
)
=
E
⁡
(
ξ
⁡
(
t
)
)
=
-
ξ
⁡
(
t
)
1
+
δ
r
⁢
e
2
*
ξ
⁡
(
t
)
,
wherein E(ξ(t)) represents the compensation modulation function, and ξ(t) represents the original modulation function.