CN201479239U - Luminance regulating circuit and set-top box having regulating circuit - Google Patents
Luminance regulating circuit and set-top box having regulating circuit Download PDFInfo
- Publication number
- CN201479239U CN201479239U CN2009202249634U CN200920224963U CN201479239U CN 201479239 U CN201479239 U CN 201479239U CN 2009202249634 U CN2009202249634 U CN 2009202249634U CN 200920224963 U CN200920224963 U CN 200920224963U CN 201479239 U CN201479239 U CN 201479239U
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- CN
- China
- Prior art keywords
- master chip
- regulating circuit
- front panel
- top box
- clock
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection
Abstract
The utility model discloses a luminance regulating circuit and a set-top box having the regulating circuit. The luminance regulating circuit comprises a main chip. An output end of the main chip is connected with an LED. A clock input end of the main chip is connected with a frequency adjusting unit for adjusting the clock frequency of the main chip. The luminance regulating circuit of the utility model can efficiently adjust the luminance of the LED connected with the output end of the front panel main chip and will not obviously interfere the video frequency.
Description
Technical field
The utility model relates to a kind of brightness regulating circuit, specifically, relates to a kind of circuit that brightness is adjusted to LED.
Background technology
Generally all be provided with standby lamp, locking lamp and power lights on the set top box front panel, standby lamp, locking lamp and power lights all adopt LED as light source.In available circuit design, power lights is directly connected on main circuit system+5V power supply, is directly powered by+5V power supply.And be connected on the output of set top box front panel master chip as the LED of standby lamp and locking lamp, provide power supply by the output of master chip.Because the power supply difference causes the brightness demonstration of standby lamp, the brightness that locks lamp and power lights inconsistent, influences the whole visual effect of set-top box.For improving the brightness of standby lamp and locking lamp, prior art generally changes its sweep waveform duty ratio by the scanning frequency that changes the front panel master chip, and then regulates the brightness of the LED of front panel master chip output connection.But this method of adjustment exists the contradiction between brightness adjustment effect and the video interference, when LED brightness adjustment effect is apparent in view, set-top box host chip and video is very easily caused bigger interference, influences view reception effect.Disturb and will consider to reduce video, then DeGrain is adjusted in LED brightness, influences the consistency that each lamp of set top box front panel and charactron brightness show.
Summary of the invention
The purpose of this utility model is the above-mentioned shortcoming and defect at set top box front panel LED brightness adjustment existence in the prior art, a kind of brightness regulating circuit is provided, can adjust the brightness of the LED that is connected front panel master chip output effectively, and guarantee video not to be caused tangible interference.
For solving the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A kind of brightness regulating circuit comprises master chip, and described master chip output is connected with LED, it is characterized in that, the input end of clock of described master chip is connected with the frequency adjustment unit of adjusting described master chip clock frequency.
According to brightness regulating circuit described in the utility model, described frequency adjustment unit includes the adjustable tuning resistor of resistance, and an end of described tuning resistor is connected the input end of clock of described master chip, the other end ground connection of described tuning resistor.
According to brightness regulating circuit described in the utility model, described tuning resistor is preferably potentiometer.
According to brightness regulating circuit described in the utility model, for reducing the drive current of master chip, the power input of described master chip connects power supply through a divider resistance.
According to brightness regulating circuit described in the utility model, the power input of described master chip also is connected with filter capacitor, the other end ground connection of described filter capacitor.
The utility model also provides a kind of set-top box, has brightness regulating circuit, described brightness regulating circuit comprises the front panel master chip, described front panel master chip output is connected with LED, it is characterized in that the input end of clock of described front panel master chip is connected with the frequency adjustment unit of adjusting described front panel master chip clock frequency.
According to set-top box described in the utility model, described frequency adjustment unit includes the adjustable tuning resistor of resistance, and an end of described tuning resistor is connected the input end of clock of described front panel master chip, the other end ground connection of described tuning resistor.
According to set-top box described in the utility model, described tuning resistor is preferably potentiometer.
According to set-top box described in the utility model, for reducing the drive current of front panel master chip, the power input of described front panel master chip connects power supply through a divider resistance.
According to set-top box described in the utility model, the power input of described front panel master chip also is connected with filter capacitor, the other end ground connection of described filter capacitor.
Compared with prior art, advantage of the present utility model and good effect are: by at master chip clock frequency input the clock frequency that the frequency adjustment unit is adjusted master chip being set, thereby can adjust its clock frequency with the variation of master chip scanning frequency, reach and in the LED brightness of adjusting the connection of master chip output, reduce the purpose of master chip output the interference of set-top box master chip and vision signal.
Description of drawings
Fig. 1 is the structured flowchart of an embodiment of the utility model brightness regulating circuit;
Fig. 2 is the physical circuit connection layout of the described embodiment of Fig. 1.
Embodiment
Below in conjunction with accompanying drawing embodiment of the present utility model is described in detail.
Figure 1 shows that the structured flowchart of an embodiment of the utility model brightness regulating circuit.This embodiment is adjusted into example with the brightness of set top box front panel LED light, described brightness regulating circuit comprises the front panel master chip, input end of clock at described front panel master chip is connected with the frequency adjustment unit of adjusting described front panel master chip clock frequency, and described front panel master chip output is connected with the LED lamp.By changing the duty ratio of described front panel master chip sweep waveform, can adjust the brightness of the LED lamp of front panel master chip output connection.When heightening the brightness of described LED lamp,, as easy as rolling off a log vision signal is caused the water wave wave interference because the output of described front panel master chip changes.Change the vision signal interference that causes for reducing the brightness of LED lamp, in the brightness of adjusting described LED lamp, utilize described frequency adjustment unit to adjust the clock frequency of described front panel master chip, realize promptly having adjusted the brightness of LED lamp, vision signal caused the purpose of interference again.
Fig. 2 shows the physical circuit connection layout of Fig. 1 embodiment.
Among the figure, N702 is the set top box front panel master chip with internal clock circuit, is connected with tuning resistor R704 as the frequency adjustment unit, the other end ground connection of described R704 at the clock signal input terminal OSC of N702.Described R704 is the adjustable tuning resistor of resistance, preferably selects potentiometer for use, also can be one group of wire jumper resistance.
Between the output SG11 of master chip N704 and output GR6, be in series with LED VD701 as set top box front panel locking lamp, wherein, the positive pole of described VD701 is connected with the SG11 terminal by current-limiting resistance R716, and the negative pole of described VD701 is connected on the GR6 terminal.Between the output SG11 of master chip N704 and output GR7, be in series with LED VD707 as set top box front panel standby lamp, wherein, the positive pole of described VD707 is connected with the SG11 terminal by current-limiting resistance R717, and the negative pole of described VD707 is connected on the GR7 terminal.
In the brightness of VD701 that changes its output by the sweep waveform duty ratio that changes described master chip N702 and VD707, correspondingly adjust the resistance of described tuning resistor R704, make VD701 and VD707 brightness with directly be connected on+during the brightness basically identical of set-top box power lights on the 5V power supply, can not cause tangible interference yet, improve the visual effect of whole video system vision signal.
Be further to reduce the interference that the brightness of adjusting VD701 and VD707 causes vision signal, this embodiment two power input VDD of master chip N702 and+be in series with divider resistance R777 between the 5V power supply.As shown in Figure 2, the power input VDD of master chip N702 is on the one hand through described divider resistance R777 connection+5V power supply, on the other hand through filter capacitor C707 ground connection; Another power input VDD of master chip N702 is on the one hand through described divider resistance R777 connection+5V power supply, on the other hand through filter capacitor C708 ground connection.+ 5V power supply is supplied with master chip N702 through described divider resistance R777 decompression back, reducing the drive current of master chip N702, thereby reduces VD701 and VD707 brightness is heightened and ripples line interference that vision signal is caused.
It is pointed out that above-mentioned brightness regulating circuit except that can adjusting the LED that is connected the master chip output, also can adjust the brightness of the charactron that constitutes by a plurality of LED as standby lamp and locking lamp.
The front panel master chip inside of the foregoing description has clock circuit, so the frequency adjustment unit that its clock end connects only includes a tuning resistor.For the master chip that needs the external clock circuit, the frequency adjustment unit that its clock end connects then is a circuit structure that comprises adjustable tuning resistor and clock circuit.
Utilize the brightness regulating circuit with frequency adjustment unit described in the utility model, can convenient and efficient ground be regulated by the LED lamp of a certain batch of producer, a certain brightness, make it to meet the demand that is fit to the user, and can not cause tangible interference, improve the overall performance of video system vision signal.
Certainly; the above only is a kind of preferred implementation of the present utility model; should be understood that; for those skilled in the art; under the prerequisite that does not break away from the utility model principle; can also make some improvements and modifications, these improvements and modifications also should be considered as protection range of the present utility model.
Claims (10)
1. a brightness regulating circuit comprises master chip, and described master chip output is connected with LED, it is characterized in that, the input end of clock of described master chip is connected with the frequency adjustment unit of adjusting described master chip clock frequency.
2. brightness regulating circuit according to claim 1 is characterized in that, described frequency adjustment unit includes the adjustable tuning resistor of resistance, and an end of described tuning resistor is connected the input end of clock of described master chip, the other end ground connection of described tuning resistor.
3. brightness regulating circuit according to claim 2 is characterized in that, described tuning resistor is a potentiometer.
4. according to each described brightness regulating circuit in the claim 1 to 3, it is characterized in that the power input of described master chip connects power supply through a divider resistance.
5. brightness regulating circuit according to claim 4 is characterized in that the power input of described master chip also is connected with filter capacitor, the other end ground connection of described filter capacitor.
6. set-top box, has brightness regulating circuit, described brightness regulating circuit comprises the front panel master chip, described front panel master chip output is connected with LED, it is characterized in that the input end of clock of described front panel master chip is connected with the frequency adjustment unit of adjusting described front panel master chip clock frequency.
7. set-top box according to claim 6 is characterized in that, described frequency adjustment unit includes the adjustable tuning resistor of resistance, and an end of described tuning resistor is connected the input end of clock of described front panel master chip, the other end ground connection of described tuning resistor.
8. set-top box according to claim 7 is characterized in that, described tuning resistor is a potentiometer.
9. according to each described set-top box in the claim 6 to 8, it is characterized in that the power input of described front panel master chip connects power supply through a divider resistance.
10. set-top box according to claim 9 is characterized in that the power input of described front panel master chip also is connected with filter capacitor, the other end ground connection of described filter capacitor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202249634U CN201479239U (en) | 2009-08-18 | 2009-08-18 | Luminance regulating circuit and set-top box having regulating circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202249634U CN201479239U (en) | 2009-08-18 | 2009-08-18 | Luminance regulating circuit and set-top box having regulating circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201479239U true CN201479239U (en) | 2010-05-19 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009202249634U Expired - Lifetime CN201479239U (en) | 2009-08-18 | 2009-08-18 | Luminance regulating circuit and set-top box having regulating circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201479239U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106612446A (en) * | 2015-10-23 | 2017-05-03 | 广东九联科技股份有限公司 | Set top box with display capable of being switched off |
-
2009
- 2009-08-18 CN CN2009202249634U patent/CN201479239U/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106612446A (en) * | 2015-10-23 | 2017-05-03 | 广东九联科技股份有限公司 | Set top box with display capable of being switched off |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20100519 |