CN111030677A - Multiplexing processing circuit, crystal oscillator multiplexing circuit and television - Google Patents
Multiplexing processing circuit, crystal oscillator multiplexing circuit and television Download PDFInfo
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- CN111030677A CN111030677A CN201911337816.2A CN201911337816A CN111030677A CN 111030677 A CN111030677 A CN 111030677A CN 201911337816 A CN201911337816 A CN 201911337816A CN 111030677 A CN111030677 A CN 111030677A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03L—AUTOMATIC CONTROL, STARTING, SYNCHRONISATION OR STABILISATION OF GENERATORS OF ELECTRONIC OSCILLATIONS OR PULSES
- H03L7/00—Automatic control of frequency or phase; Synchronisation
- H03L7/06—Automatic control of frequency or phase; Synchronisation using a reference signal applied to a frequency- or phase-locked loop
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
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- H04N5/44—Receiver circuitry for the reception of television signals according to analogue transmission standards
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Abstract
The application relates to a multiplexing processing circuit, crystal oscillator multiplexing circuit and TV set, multiplexing processing circuit includes: the emitter follower circuit is connected with the crystal oscillator clock circuit and is used for enhancing the driving capability of the crystal oscillator clock circuit; the resonant circuit is connected with the emitter follower circuit and is used for filtering the interference of clutter signals outside the working frequency of the crystal oscillator on the second chip; the high-frequency filter is connected with the resonance circuit and is used for filtering clutter signals of very high frequency and ultrahigh frequency; and the signal matching module is connected with the high-frequency filter and used for enabling the clock signal to meet the requirement of the second chip. Through the multiplexing processing circuit in the application, under the condition that the chip does not need to have a special crystal oscillator processing output function, the clock circuit of a single crystal oscillator can be used for simultaneously providing clock reference signals for a plurality of chips, the cost of the circuit is reduced, the limitation to the functions of the chips and the suppliers of the chips is avoided, and the application range is wide.
Description
Technical Field
The present disclosure relates to electronic circuits, and particularly to a multiplexing processing circuit, a crystal oscillator multiplexing circuit, and a television.
Background
At present, more than two crystal oscillators with the same working frequency are usually used for a television mainboard as clock circuits of different chips such as a System-on-a-Chip (SoC) and a tuner. If the cost is reduced, a single crystal oscillator can be used for simultaneously providing reference clocks for different chips such as the SoC and the tuner, and the like, and the chip is required to support the clock output function of special processing in such a way, otherwise, the single crystal oscillator is directly connected to different chips, mutual crosstalk can be generated, and the clock reference signals of different chips such as the SoC and the tuner are unstable.
In the middle and low-end markets of televisions, competition is extremely intense, and cost pressure is high. It is costly if each chip uses a separate crystal oscillator circuit to provide the reference clock. If the crystal oscillator needs to be reused, the single crystal oscillator can provide reference clocks for a plurality of chips at the same time, the cost of the television core can be effectively reduced, and the product competitiveness is improved. However, the conventional method of outputting the clock signal after the chip is specially processed inside the chip is usually adopted, so that the cost reduction measure depends on and is limited by the functions of the chip and the suppliers of the chip, and the method is not suitable for wide popularization.
Therefore, the prior art is in need of improvement.
Disclosure of Invention
The technical problem to be solved in the present application is to provide a multiplexing processing circuit, a crystal oscillator multiplexing circuit and a television, which can simultaneously provide clock reference signals for a plurality of chips by using a clock circuit of a single crystal oscillator without the need of the chips having a special crystal oscillator processing output function, thereby reducing the cost of the circuit, avoiding the limitation of the functions of the chips and the suppliers of the chips, and having a wide application range.
In a first aspect, an embodiment of the present application provides a multiplexing processing circuit, where the multiplexing processing circuit includes:
the emitter follower circuit is connected with the crystal oscillator clock circuit and is used for enhancing the driving capability of the crystal oscillator clock circuit;
the resonant circuit is connected with the emitter follower circuit and is used for filtering the interference of clutter signals outside the working frequency of the crystal oscillator on the second chip;
the high-frequency filter is connected with the resonance circuit and is used for filtering clutter signals of very high frequency and ultrahigh frequency;
and the signal matching module is connected with the high-frequency filter and used for enabling the clock signal to meet the requirement of the second chip.
Optionally, the emitter follower circuit comprises:
the circuit comprises a first resistor, a second resistor, a third resistor and a triode;
the second end of the first resistor is connected with the base electrode of the triode; a collector of the triode is connected with a power supply, and an emitter of the triode is respectively connected with a first end of the second resistor and a first end of the third resistor; and the second end of the third resistor is grounded.
Optionally, the resonant circuit comprises:
an inductor and a first capacitor;
the first end of the inductor is connected with the second end of the second resistor; the second end of the inductor is connected with the first end of the first capacitor.
Optionally, the high frequency filter includes:
a second capacitor;
and the first end of the second capacitor is connected with the second end of the first capacitor, and the second end of the second capacitor is grounded.
Optionally, the signal matching module includes:
a fourth resistor;
and the first end of the fourth resistor is connected with the second end of the first capacitor.
In a second aspect, an embodiment of the present application provides a crystal oscillator multiplexing circuit, including:
the multiplexing processing circuit of any one of claims 1 to 5, wherein the crystal oscillator clock circuit provides a clock signal for the chip;
the first chip is connected with the input end of the crystal oscillator clock circuit, the output end of the crystal oscillator clock circuit is connected with the first end of the multiplexing processing circuit, and the second end of the multiplexing processing circuit is connected with the second chip.
The crystal oscillator multiplexing circuit comprises:
the system comprises a plurality of multiplexing processing circuits, a first chip and a plurality of second chips, wherein the number of the second chips is consistent with that of the multiplexing processing circuits;
and the first end of the multiplexing processing circuit is connected with the output end of the crystal oscillator clock circuit, and the second end of the multiplexing processing circuit is connected with the second chip.
Optionally, the crystal oscillator clock circuit includes:
a third capacitor, a fourth capacitor and a crystal oscillator;
the first end of the fourth capacitor is connected with the first end of the crystal oscillator;
the first end of the third capacitor is connected with the third end of the crystal oscillator;
the second end of the third capacitor, the second end of the fourth capacitor, the second end of the crystal oscillator and the fourth end of the crystal oscillator are all grounded;
the first end of the third capacitor is an output end, and the first end of the fourth capacitor is an input end.
In a third aspect, an embodiment of the present application provides a television, where the television includes the above crystal oscillator multiplexing circuit.
Compared with the prior art, the embodiment of the application has the following advantages:
according to the multiplexing processing circuit provided by the embodiment of the application, the emitter follower circuit is connected with the crystal oscillator clock circuit and is used for enhancing the driving capability of the crystal oscillator clock circuit; the resonant circuit is connected with the emitter follower circuit and is used for filtering the interference of clutter signals outside the working frequency of the crystal oscillator on the second chip; the high-frequency filter is connected with the resonance circuit and is used for filtering clutter signals of very high frequency and ultrahigh frequency; and the signal matching module is connected with the high-frequency filter and used for enabling the clock signal to meet the requirement of the second chip. By the multiplexing processing circuit, a clock reference signal can be provided for a plurality of chips by the clock circuit of a single crystal oscillator under the condition that the chips do not need to have a special crystal oscillator processing output function, so that the cost of the circuit is reduced, the limitation to the functions of the chips and suppliers of the chips is avoided, and the application range is wide.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a circuit diagram of a crystal oscillator multiplexing circuit according to an embodiment of the present application;
fig. 2 is a circuit diagram of another crystal oscillator multiplexing circuit according to an embodiment of the present application.
Detailed Description
In order to make the technical solutions of the present application better understood, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The inventor finds that when a single crystal oscillator is used for simultaneously providing reference clocks for different chips such as SoC and tuner, the chip is required to support a clock output function of special processing, otherwise, the crystal oscillator signal is directly connected to different chips, mutual crosstalk is generated, and clock reference signals of different chips such as SoC and tuner are unstable, so that the cost reduction measure depends on and is limited by the functions of the chips and suppliers of the chips, and the wide-range popularization is not convenient.
In order to solve the above problems, in the embodiment of the present application, by using the multiplexing processing circuit, a clock circuit of a single crystal oscillator can be used to provide clock reference signals for a plurality of chips at the same time without the need of the chips having a special crystal oscillator processing output function, thereby reducing the cost of the circuit, avoiding the limitation on the functions of the chips and the suppliers of the chips, and having a wide application range.
Various non-limiting embodiments of the present application are described in detail below with reference to the accompanying drawings.
An embodiment of the present application provides a multiplexing processing circuit, as shown in fig. 1, where the multiplexing processing circuit 10 includes:
an emitter follower circuit 100 connected to the crystal clock circuit 20 for enhancing the driving capability of the crystal clock circuit;
a resonant circuit 102 connected to the emitter follower circuit 100 for filtering the interference of the noise signal outside the operating frequency of the first chip 30 to the second chip 40;
a high-frequency filter 104 connected to the resonant circuit 102 for filtering out very high frequency and ultra high frequency clutter signals;
and a signal matching module 106, connected to the high-frequency filter 104, for enabling the clock signal to meet the requirements of the second chip 40.
In the embodiment of the present application, the emitter follower circuit 100 can enhance the driving capability of the conventional crystal oscillator clock circuit, so that the clock circuit of a single crystal oscillator can simultaneously provide clock reference signals for a plurality of chips, and can isolate the influence of the clock signal accessed by the second chip on the clock amplitude of the crystal oscillator, thereby preventing the clock signal of the first chip from being pulled down to cause the abnormal operation of the first chip; the resonant circuit 102 has a resonant frequency close to the working frequency of the crystal oscillator, and plays a role of a band-pass filter to filter the interference of most of other clutter signals outside the working frequency of the crystal oscillator on the second chip; the high-frequency filter 104 is used for filtering the interference of the clutter signals of the very high frequency and the ultrahigh frequency range on the circuit to the second chip; and the signal matching module 106 is configured according to the internal designed impedance of the second chip, so that the clock signal multiplexed by the crystal oscillator can meet the internal impedance requirement of the second chip.
That is to say, the conventional crystal oscillator clock circuit is driven by the emitter follower circuit 100 composed of the first resistor R1, the second resistor R2, the third resistor R3 and the triode in an enhanced manner, noise signals outside most of the crystal oscillator working frequency are filtered by the resonance circuit 102 composed of the inductor L1 and the first capacitor C1, noise signals outside the very high frequency and ultra high frequency bands are filtered by the high frequency filter 104, the matching of the internal impedance of the second chip is performed by the signal matching module 106, and finally a stable clock reference signal is provided to the second chip 40, and meanwhile, the emitter follower circuit 100 isolates the influence of the second chip on the first chip clock reference signal.
In the embodiment of the application, the crystal oscillator clock circuit can provide simultaneous clock signals for a plurality of chips through the crystal oscillator multiplexing circuit. The first chip may be an SoC chip and the second chip may be a Tuner chip.
In an alternative embodiment, the first resistance is 1kΩThe model of the triode is S9018, and the second resistor is 10ΩAnd the third resistance is 220ΩThe first inductor is 560nH, the first capacitor is 82pF, the second capacitor is 6.8pF, and the fourth resistor is 750ΩThe power supply voltage is 5V.
In the embodiment of the present application, the emitter follower circuit 100 includes:
the circuit comprises a first resistor R1, a second resistor R2, a third resistor R3 and a triode;
the second end of the first resistor R1 is connected with the base of the triode; a collector of the triode is connected with a power supply, and an emitter of the triode is respectively connected with a first end of the second resistor R2 and a first end of the third resistor R3; the second end of the third resistor R3 is grounded.
In the embodiment of the present application, the resonant circuit 102 includes:
an inductor L1 and a first capacitor C1;
a first end of the inductor L1 is connected with a second end of the second resistor R2; the second end of the inductor L1 is connected to the first end of the first capacitor C1.
In the embodiment of the present application, the high frequency filter 104 includes:
a second capacitance C2;
the first end of the second capacitor C2 is connected to the second end of the first capacitor C1, and the second end of the second capacitor C2 is grounded.
In an embodiment of the present application, the signal matching module includes:
a fourth resistor R4;
the first end of the fourth resistor R4 is connected with the second end of the first capacitor C1.
An embodiment of the present application provides a crystal oscillator multiplexing circuit, as shown in fig. 1, the crystal oscillator multiplexing circuit includes:
the system comprises a crystal oscillator clock circuit 20, at least two chips and at least one multiplexing processing circuit 10, wherein the crystal oscillator clock circuit provides clock signals for the chips;
the first chip 30 is connected to the input end of the crystal oscillator clock circuit 20, the output end of the crystal oscillator clock circuit 20 is connected to the first end of the multiplexing processing circuit 10, and the second end of the multiplexing processing circuit 10 is connected to the second chip 40.
In the embodiment of the application, the crystal oscillator clock circuit can provide clock signals for a plurality of chips simultaneously through the crystal oscillator multiplexing circuit. The first chip may be an SoC chip and the second chip may be a Tuner chip.
In an optional manner of the embodiment of the present application, the multiplexing processing circuit may be connected to the crystal oscillator clock circuit to provide clock signals for two chips at the same time, and the following description will take the first chip as an SoC chip and the second chip as a Tuner chip.
The SoC chip is connected with the input end of the crystal oscillator clock circuit, the output end of the crystal oscillator clock circuit is respectively connected with the SoC chip and the first end of the first resistor in the multiplexing processing circuit, and the second end of the fourth resistor in the multiplexing processing circuit is connected with the Tuner chip. The structure of the multiplexing processing circuit is described above, and is not described herein again.
In another optional manner of the embodiment of the present application, a multiplexing processing circuit may be connected to a crystal oscillator clock circuit to simultaneously provide clock signals for two or more chips, as shown in fig. 2, where the crystal oscillator multiplexing circuit includes:
the system comprises a plurality of multiplexing processing circuits, a first chip and a plurality of second chips, wherein the number of the second chips is consistent with that of the multiplexing processing circuits;
and the first end of the multiplexing processing circuit is connected with the output end of the crystal oscillator clock circuit, and the second end of the multiplexing processing circuit is connected with the second chip.
In this embodiment of the application, the chip connected to the second end of the fourth resistor in the multiplexing processing circuit is the second chip, and the kind of the second chip may be different, for example, the second chip may be Tuner, Demodulator, MCU, or the like. The number of the second chips is consistent with that of the multiplexing processing circuits, namely, each second chip is connected with the crystal oscillator clock circuit through one multiplexing processing circuit. The following description is given by using an SoC chip, a Tuner chip, and a Demodulator, where the first chip is the SoC chip, and the second chip is the Demodulator chip and the Tuner chip.
Specifically, as shown in fig. 2, the crystal oscillator multiplexing circuit includes: the circuit comprises a crystal oscillator clock circuit, an SoC chip, a Tuner chip, a Demodulator and two multiplexing processing circuits.
The SoC chip is connected with the input end of the crystal oscillator clock circuit, the output end of the crystal oscillator clock circuit is respectively connected with the SoC chip and the first ends of the first resistors in the two multiplexing processing circuits, the second end of the fourth resistor R4 in one multiplexing processing circuit 10 is connected with the Tuner chip 40, and the second end of the fourth resistor R4 in the other multiplexing processing circuit 11 is connected with the Demodulator chip 41. The structure of the multiplexing processing circuit is described above, and is not described herein again.
In the embodiment of the present application, the crystal clock circuit 20 includes:
a third capacitor C3, a fourth capacitor C4 and a crystal oscillator Z1;
a first terminal of a fourth capacitor C4 is connected with a first terminal of the crystal oscillator Z1;
the first end of a third capacitor C3 is connected with the third end of the crystal oscillator Z1;
the second terminal of the third capacitor C3, the second terminal of the fourth capacitor C4, the second terminal of the crystal oscillator Z1 and the fourth terminal of the crystal oscillator Z1 are all grounded;
the first terminal of the third capacitor C3 is the output terminal and the first terminal of the fourth capacitor C4 is the input terminal.
In the embodiment of the present application, an input terminal XI of the crystal oscillator clock circuit 20 is connected to the SoC chip, and an output terminal XO of the crystal oscillator clock circuit 20 is connected to the SoC chip and a first terminal of a first resistor R1 in the multiplexing processing circuit 10, respectively; the second terminal of the fourth resistor R4 in the multiplexing processing circuit 10 is connected to the Tuner chip.
In an alternative embodiment, the crystal oscillator is 24MHz, the third capacitor is 18pF, and the fourth capacitor is 18 pF.
The embodiment of the application provides a television, which comprises the crystal oscillator multiplexing circuit.
Through the multiplexing processing circuit in the application, under the condition that an SoC chip does not need to have a special crystal oscillator processing output function, a clock circuit of a single crystal oscillator can be used for simultaneously providing clock reference signals for a plurality of chips, the cost of the circuit is reduced, the limitation to the functions of the chips and the suppliers of the chips is avoided, and the application range is wide.
The technical features of the above embodiments can be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the above embodiments are not described, but should be considered as the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (9)
1. A multiplexing processing circuit, comprising:
the emitter follower circuit is connected with the crystal oscillator clock circuit and is used for enhancing the driving capability of the crystal oscillator clock circuit;
the resonant circuit is connected with the emitter follower circuit and is used for filtering the interference of clutter signals outside the working frequency of the crystal oscillator on the second chip;
the high-frequency filter is connected with the resonance circuit and is used for filtering clutter signals of very high frequency and ultrahigh frequency;
and the signal matching module is connected with the high-frequency filter and used for enabling the clock signal to meet the requirement of the second chip.
2. The multiplexing processing circuit of claim 1, wherein the emitter follower circuit comprises:
the circuit comprises a first resistor, a second resistor, a third resistor and a triode;
the second end of the first resistor is connected with the base electrode of the triode; a collector of the triode is connected with a power supply, and an emitter of the triode is respectively connected with a first end of the second resistor and a first end of the third resistor; and the second end of the third resistor is grounded.
3. The multiplexing processing circuit of claim 2 wherein the resonant circuit comprises:
an inductor and a first capacitor;
the first end of the inductor is connected with the second end of the second resistor; the second end of the inductor is connected with the first end of the first capacitor.
4. The multiplexing processing circuit of claim 3 wherein the high frequency filter comprises:
a second capacitor;
and the first end of the second capacitor is connected with the second end of the first capacitor, and the second end of the second capacitor is grounded.
5. The multiplexing processing circuit of claim 3 wherein the signal matching module comprises:
a fourth resistor;
and the first end of the fourth resistor is connected with the second end of the first capacitor.
6. A crystal oscillator multiplexing circuit, comprising:
the multiplexing processing circuit of any one of claims 1 to 5, wherein the crystal oscillator clock circuit provides a clock signal for the chip;
the first chip is connected with the input end of the crystal oscillator clock circuit, the output end of the crystal oscillator clock circuit is connected with the first end of the multiplexing processing circuit, and the second end of the multiplexing processing circuit is connected with the second chip.
7. The crystal oscillator multiplexing circuit according to claim 6, wherein the crystal oscillator multiplexing circuit comprises:
the system comprises a plurality of multiplexing processing circuits, a first chip and a plurality of second chips, wherein the number of the second chips is consistent with that of the multiplexing processing circuits;
and the first end of the multiplexing processing circuit is connected with the output end of the crystal oscillator clock circuit, and the second end of the multiplexing processing circuit is connected with the second chip.
8. The crystal oscillator multiplexing circuit according to claim 6, wherein the crystal oscillator clock circuit comprises:
a third capacitor, a fourth capacitor and a crystal oscillator;
the first end of the fourth capacitor is connected with the first end of the crystal oscillator;
the first end of the third capacitor is connected with the third end of the crystal oscillator;
the second end of the third capacitor, the second end of the fourth capacitor, the second end of the crystal oscillator and the fourth end of the crystal oscillator are all grounded;
the first end of the third capacitor is an output end, and the first end of the fourth capacitor is an input end.
9. A television set, characterized in that it comprises a crystal oscillator multiplexing circuit according to any of claims 6 to 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911337816.2A CN111030677A (en) | 2019-12-23 | 2019-12-23 | Multiplexing processing circuit, crystal oscillator multiplexing circuit and television |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911337816.2A CN111030677A (en) | 2019-12-23 | 2019-12-23 | Multiplexing processing circuit, crystal oscillator multiplexing circuit and television |
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| CN111030677A true CN111030677A (en) | 2020-04-17 |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103825552A (en) * | 2012-11-19 | 2014-05-28 | 苏州工业园区新宏博通讯科技有限公司 | Crystal-oscillator circuit shared by multiple chips |
| CN207380603U (en) * | 2017-08-16 | 2018-05-18 | 深圳市芯智科技有限公司 | A kind of crystal oscillator common circuit for being used to implement clock synchronization |
| CN110471490A (en) * | 2019-07-12 | 2019-11-19 | 晶晨半导体(上海)股份有限公司 | A kind of no source crystal oscillator common circuit |
-
2019
- 2019-12-23 CN CN201911337816.2A patent/CN111030677A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103825552A (en) * | 2012-11-19 | 2014-05-28 | 苏州工业园区新宏博通讯科技有限公司 | Crystal-oscillator circuit shared by multiple chips |
| CN207380603U (en) * | 2017-08-16 | 2018-05-18 | 深圳市芯智科技有限公司 | A kind of crystal oscillator common circuit for being used to implement clock synchronization |
| CN110471490A (en) * | 2019-07-12 | 2019-11-19 | 晶晨半导体(上海)股份有限公司 | A kind of no source crystal oscillator common circuit |
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