CN201378416Y - Backlight control circuit and TV set provided with the same - Google Patents
Backlight control circuit and TV set provided with the same Download PDFInfo
- Publication number
- CN201378416Y CN201378416Y CN200920144481U CN200920144481U CN201378416Y CN 201378416 Y CN201378416 Y CN 201378416Y CN 200920144481 U CN200920144481 U CN 200920144481U CN 200920144481 U CN200920144481 U CN 200920144481U CN 201378416 Y CN201378416 Y CN 201378416Y
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- backlight control
- voltage
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- control circuit
- branch road
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Abstract
The utility model discloses a backlight control circuit and a TV set provided with the same, relates to the technical field of control circuits, and aims to solve the problems that the design cost of the circuit is bigger as master control chips of backlight control circuit provide more input pins for backlight control circuit input and more backlight control output branch lines in the prior art. The backlight control circuit provided by the utility model comprises a backlight control input branch line with adjustable voltage and a backlight control output branch line, wherein the backlight control input branch line with adjustable voltage is connected with the backlight control output branch line. Adopting the backlight control circuit of the utility model, the master control chip only needs to provide one input pin and one backlight control output branch line for the backlight control circuit, and then the output of a plurality of voltages can be realized.
Description
Technical field
The utility model relates to a kind of control circuit, relates in particular to a kind of backlight control circuit and has the televisor of this circuit.
Background technology
At present, the LCD LCD TV realizes brightness energy-conservation or the change image by controlling brightness backlight.Usually LCD TV voltage that backlight control circuit output is set has standard and two states such as energy-conservation.The voltage status of described two kinds of backlight control circuits output, selecting the input pin of backlight control circuit by the main control chip is that input voltage decides.If the voltage of the input pin of described backlight control circuit input is low level, then the backlight control voltage of backlight control circuit output is power save mode voltage; If the input pin voltage of described backlight control circuit is high level, then the backlight control voltage of backlight control circuit output is standard conditions voltage.In like manner, if when needing voltage to backlight control circuit output to carry out the selection of various states in described LCD LCD TV, the main control chip just need provide input control voltage for backlight control circuit for the pin that backlight control circuit is provided with corresponding number.
In realizing process of the present utility model, the designer finds to have following problem in the prior art at least: main control chip used in the prior art carries out the setting of pin number according to the voltage status of backlight control circuit output.Because the difference of backlight control circuit output voltage state, just need the main control chip to provide a correspondent voltage input pin for backlight control circuit, make the main control chip more for the input pin that backlight control circuit provides, and the device that the respective branch of backlight control circuit design needs is also more, thereby cause the design cost of backlight control circuit higher.
The utility model content
For the main control chip that solves backlight control circuit in the prior art for the input pin that the backlight control circuit input provides is many, cause the bigger problem of circuit design cost, the utility model provides a kind of backlight control circuit and has had the televisor of this circuit.
A kind of backlight control circuit that the utility model provides comprises: a backlight control input branch road and the backlight control output branch road that voltage is adjustable; The backlight control input branch road that described voltage is adjustable links to each other with described backlight control output branch road.
Further, the backlight control input branch road that described voltage is adjustable comprises: the main control chip of an adjustable backlight control circuit input voltage, first pull-up resistor; Described backlight control output branch road comprises: a current-limiting resistance, triode, second pull-up resistor and an integral filter circuit;
The main control chip of described adjustable backlight control circuit input voltage links to each other with an end of described current-limiting resistance one end, described first pull-up resistor respectively by a pin; The other end of described current-limiting resistance links to each other with described transistor base;
The described first pull-up resistor other end links to each other with external power supply;
The collector of described triode links to each other with an end of described second pull-up resistor, one end, described integral filter circuit respectively;
The other end of described second pull-up resistor links to each other with external power supply;
The other end of described integral filter circuit is used to export backlight control voltage;
The grounded emitter of described triode.
Further, the main control chip of described adjustable backlight control circuit input voltage carries out the adjustment of backlight control circuit input voltage by the mode of pulse-length modulation.
Further, described integral filter circuit comprises: a resistance and an electric capacity;
Described resistance one end links to each other with the collector of described triode, and the other end links to each other with described electric capacity, and output backlight control voltage;
Described electric capacity other end ground connection.
A kind of televisor that the utility model provides comprises: backlight control circuit; This circuit is by adjusting the input voltage of backlight control input branch road, the backlight control voltage of control backlight control output branch road output.
Further, described backlight control circuit comprises: a backlight control input branch road and the backlight control output branch road that voltage is adjustable; The backlight control input branch road that described voltage is adjustable links to each other with described backlight control output branch road.
Further, the backlight control input branch road that described voltage is adjustable comprises: the main control chip of an adjustable backlight control circuit input voltage, first pull-up resistor; Described backlight control output branch road comprises: a current-limiting resistance, triode, second pull-up resistor and an integral filter circuit;
The main control chip of described adjustable backlight control circuit input voltage links to each other with an end of described current-limiting resistance one end, described first pull-up resistor respectively by a pin; The other end of described current-limiting resistance links to each other with described transistor base;
The described first pull-up resistor other end links to each other with external power supply;
The collector of described triode links to each other with an end of described second pull-up resistor, one end, described integral filter circuit respectively;
The other end of described second pull-up resistor links to each other with external power supply;
The other end of described integral filter circuit is used to export backlight control voltage;
The grounded emitter of described triode.
Further, the main control chip of described adjustable backlight control circuit input voltage carries out the adjustment of backlight control circuit input voltage by the mode of pulse-length modulation.
Further, described integral filter circuit comprises: a resistance and an electric capacity;
Described resistance one end links to each other with the collector of described triode, and the other end links to each other with described electric capacity, and output backlight control voltage;
Described electric capacity other end ground connection.
The backlight control circuit that the utility model provides and have the televisor of this circuit, control the backlight control voltage of backlight control output branch road output by an adjustable backlight control input branch road of voltage, thereby make main control chip in the adjustable backlight control of the voltage input branch road only need the input voltage of the backlight control circuit adjusted be input to described backlight control output branch road, and then output backlight control voltage by a pin.In prior art, the different main control pin of chip of input voltage needs of different backlight control circuits are exported to different backlight control output branch roads and are compared, and the present invention only needs a pin that the voltage of adjusting is exported to a backlight control output branch road.Like this, not only the pin utilization factor of main control chip improves greatly, and has saved the required device of design multichannel backlight control input/out branch, thereby greatly reduces design cost.
Description of drawings
The example structure synoptic diagram of a kind of backlight control circuit that Fig. 1 provides for the utility model;
The example structure synoptic diagram of a kind of televisor that Fig. 2 provides for the utility model.
Embodiment
A kind of backlight control circuit that the utility model embodiment is provided below in conjunction with accompanying drawing and the televisor with this circuit are described in detail.
As shown in Figure 1, a kind of backlight control circuit that provides for the utility model embodiment; This circuit comprises:
Article one, adjustable backlight control input branch road and the backlight control of voltage exported branch road; The backlight control input branch road that described voltage is adjustable links to each other with described backlight control output branch road.
Wherein, the backlight control input branch road that described voltage is adjustable comprises: the main control chip of an adjustable backlight control circuit input voltage, the first pull-up resistor R4; Described backlight control output branch road comprises: a current-limiting resistance R1, triode Q1, second a pull-up resistor R2 and an integral filter circuit;
The main control chip of described adjustable backlight control circuit input voltage links to each other with the end of described current-limiting resistance R1 one end, the described first pull-up resistor R4 respectively by a pin N1; The other end of described current-limiting resistance R1 links to each other with described triode Q1 base stage;
The described first pull-up resistor R4 other end links to each other with external power supply+3.3V;
The collector of described triode Q1 links to each other with an end of the described second pull-up resistor R2, one end, described integral filter circuit respectively;
The other end of the described second pull-up resistor R2 links to each other with external power supply+5V;
The other end of described integral filter circuit is used to export backlight control voltage;
The grounded emitter of described triode Q1.
The main control chip that it should be noted that described adjustable backlight control circuit input voltage carries out the adjustment of backlight control circuit input voltage by pulse-length modulation (Pulse Width Modulation the is called for short PWM) mode of pulse-length modulation.
When described integral filter circuit, comprising: a resistance R 3 and a capacitor C 1;
Described resistance R 3 one ends link to each other with the collector of described triode Q1, and the other end links to each other with described capacitor C 1, and output backlight control voltage;
Described capacitor C 1 other end ground connection.
It should be noted that in the quiescent point that above-mentioned triode Q1 is set, establish R1=4.7K; R2=10K; R3=10K; R4=1K.Low level occurs when N1 controls, promptly the base stage of Q1 is 0V.Because VB-VE=0V＜0.7V, so Q1 is in cut-off state; High level occurs when N1 controls, promptly 3.3V voltage can calculate (3.3-0.7)/(R1+R4)=0.46mA like this through the base stage that R1 is added to Q1; Suppose to be in state of saturation, then calculate IC=5/R2=0.5m A, can obtain by the transistorized curve of output of Q1, work as IB=0.43mA, triode common emitter enlargement factor is about 200.Because the enlargement factor * IB of triode is much larger than IC, so pipe is in degree of depth state of saturation.So just can guarantee the on off state of triode.
Below the course of work by concrete backlight control circuit foregoing circuit is described in detail.
Because different backlight control voltage can be adjusted different backlight illuminations.In described backlight control circuit, the main control chip can be adjusted backlight control circuit frequency of input voltage and dutycycle by PWM, and then changes the output backlight control voltage of backlight control circuit.The concrete course of work of described backlight control circuit is as follows:
At first, the main control chip is by PWM waveform of pin N1 output, and the frequency of this waveform and dutycycle can be adjusted by user's needs.
It should be noted that, if the dutycycle of main control pin of chip N1 output PWM waveform is A, after the paraphase of the PWM waveform of output through the Q1 pipe, a peak-to-peak value having occurred at the collector of Q1 is 5V, and the PWM ripple is the 1-A of PWM ripple in the base stage dutycycle in the collector dutycycle.Describedly carry out filtering by integral filter circuit, the high-frequency ac voltage of described collector place is converted into galvanic current presses at the PWM of collector place ripple.
Then, the waveform of described PWM is the integral action of R3 and C1 through integral filter circuit, forms galvanic current and presses, and is exported by the backlight control voltage pin.
It should be noted that the R3 resistance value is provided with relevant with the ripple factor of described PWM waveform with C1 electric capacity in the described integral filter circuit.When from the frequency of the PWM1 waveform of N1 output when high, the PWM2 waveform frequency that forms at the Q1 collector is just high; When the integration constant and dutycycle one timing of integral filter circuit, the backlight control voltage of the high more then output of frequency is just high more.When the dutycycle of PWM1 more little, the integration constant of frequency and integral filter circuit one regularly, then Shu Chu voltage is also just high more.For example: on this machine, adopt the pattern of 2 kinds of control voltages backlight, i.e. standard and energy saver mode.The method of specific implementation is as follows:
When under mode standard, the PWM waveform frequency of the N1 pin of main control chip output is: f=8.4KHz, and dutycycle is: 16%, this moment, the backlight control voltage of output was 1.637V; When under energy saver mode, the frequency of the N1 pin of main control chip output is: f=8.4KHz, and dutycycle is: 4%, this moment, the backlight control voltage of output was 3.321V.
It is also to be noted that, the Q1 that in this machine, adopts be the chip triode MMBT3904LT1 TP during ROH, the maximum frequency that its maximum base stage can be imported is 300MHZ, also to consider the junction capacity of triode Q1 base stage and emitter this moment, because R1 has also formed low-pass filter in this junction capacity, if frequency is too high, signal attenuation can be fallen.
As shown in Figure 2, a kind of televisor that provides for the utility model; This televisor comprises: backlight control circuit; This circuit is by adjusting the input voltage of backlight control input branch road, the backlight control voltage of control backlight control output branch road output.
Wherein, described backlight control circuit comprises: a backlight control input branch road and the backlight control output branch road that voltage is adjustable; The backlight control input branch road that described voltage is adjustable links to each other with described backlight control output branch road.
When the adjustable backlight control input branch road of described voltage, comprising: the main control chip of an adjustable backlight control circuit input voltage, first pull-up resistor; Described backlight control output branch road comprises: a current-limiting resistance, triode, second pull-up resistor and an integral filter circuit;
The main control chip of described adjustable backlight control circuit input voltage links to each other with an end of described current-limiting resistance one end, described first pull-up resistor respectively by a pin; The other end of described current-limiting resistance links to each other with described transistor base;
The described first pull-up resistor other end links to each other with external power supply;
The collector of described triode links to each other with an end of described second pull-up resistor, one end, described integral filter circuit respectively;
The other end of described second pull-up resistor links to each other with external power supply;
The other end of described integral filter circuit is used to export backlight control voltage;
The grounded emitter of described triode.
It should be noted that the main control chip of described adjustable backlight control circuit input voltage carries out the adjustment of backlight control circuit input voltage by the mode of pulse-length modulation.
When described integral filter circuit, comprising: a resistance and an electric capacity;
Described resistance one end links to each other with the collector of described triode, and the other end links to each other with described electric capacity, and output backlight control voltage;
Described electric capacity other end ground connection.
The backlight control circuit that the utility model provides and have the televisor of this circuit, control the backlight control voltage of backlight control output branch road output by an adjustable backlight control input branch road of voltage, thereby make main control chip in the adjustable backlight control of the voltage input branch road only need the input voltage of the backlight control circuit adjusted be input to described backlight control output branch road, and then output backlight control voltage by a pin.In prior art, the different main control pin of chip of input voltage needs of different backlight control circuits are exported to different backlight control output branch roads and are compared, and the present invention only needs a pin that the voltage of adjusting is exported to a backlight control output branch road.Like this, not only the pin utilization factor of main control chip improves greatly, and has saved the required device of design multichannel backlight control input/out branch, thereby greatly reduces design cost.
The above; it only is embodiment of the present utility model; protection domain of the present utility model is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the utility model discloses; can expect easily changing or replacing, all should be encompassed within the protection domain of the present utility model.
Claims (8)
1, a kind of backlight control circuit is characterized in that, comprising: a backlight control input branch road and the backlight control output branch road that voltage is adjustable; The backlight control input branch road that described voltage is adjustable links to each other with described backlight control output branch road.
2, backlight control circuit according to claim 1 is characterized in that, the backlight control input branch road that described voltage is adjustable comprises: the main control chip of an adjustable backlight control circuit input voltage, first pull-up resistor; Described backlight control output branch road comprises: a current-limiting resistance, triode, second pull-up resistor and an integral filter circuit;
The main control chip of described adjustable backlight control circuit input voltage links to each other with an end of described current-limiting resistance one end, described first pull-up resistor respectively by a pin; The other end of described current-limiting resistance links to each other with described transistor base;
The described first pull-up resistor other end links to each other with external power supply;
The collector of described triode links to each other with an end of described second pull-up resistor, one end, described integral filter circuit respectively;
The other end of described second pull-up resistor links to each other with external power supply;
The other end of described integral filter circuit is used to export backlight control voltage;
The grounded emitter of described triode.
3, backlight control circuit according to claim 2 is characterized in that, the main control chip of described adjustable backlight control circuit input voltage carries out the adjustment of backlight control circuit input voltage by the mode of pulse-length modulation.
4, according to claim 2 or 3 described backlight control circuits, it is characterized in that described integral filter circuit comprises: a resistance and an electric capacity;
Described resistance one end links to each other with the collector of described triode, and the other end links to each other with described electric capacity, and output backlight control voltage;
Described electric capacity other end ground connection.
5, a kind of televisor is characterized in that, comprising: backlight control circuit;
Described backlight control circuit comprises: a backlight control input branch road and the backlight control output branch road that voltage is adjustable; The backlight control input branch road that described voltage is adjustable links to each other with described backlight control output branch road; Described backlight control circuit is by adjusting the input voltage of backlight control input branch road, the backlight control voltage of control backlight control output branch road output.
6, televisor according to claim 5 is characterized in that, the backlight control input branch road that described voltage is adjustable comprises: the main control chip of an adjustable backlight control circuit input voltage, first pull-up resistor; Described backlight control output branch road comprises: a current-limiting resistance, triode, second pull-up resistor and an integral filter circuit;
The main control chip of described adjustable backlight control circuit input voltage links to each other with an end of described current-limiting resistance one end, described first pull-up resistor respectively by a pin; The other end of described current-limiting resistance links to each other with described transistor base;
The described first pull-up resistor other end links to each other with external power supply;
The collector of described triode links to each other with an end of described second pull-up resistor, one end, described integral filter circuit respectively;
The other end of described second pull-up resistor links to each other with external power supply;
The other end of described integral filter circuit is used to export backlight control voltage;
The grounded emitter of described triode.
7, televisor according to claim 6 is characterized in that, the main control chip of described adjustable backlight control circuit input voltage carries out the adjustment of backlight control circuit input voltage by the mode of pulse-length modulation.
8, according to claim 6 or 7 described televisors, it is characterized in that described integral filter circuit comprises: a resistance and an electric capacity;
Described resistance one end links to each other with the collector of described triode, and the other end links to each other with described electric capacity, and output backlight control voltage;
Described electric capacity other end ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920144481U CN201378416Y (en) | 2009-02-23 | 2009-02-23 | Backlight control circuit and TV set provided with the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200920144481U CN201378416Y (en) | 2009-02-23 | 2009-02-23 | Backlight control circuit and TV set provided with the same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201378416Y true CN201378416Y (en) | 2010-01-06 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200920144481U Expired - Fee Related CN201378416Y (en) | 2009-02-23 | 2009-02-23 | Backlight control circuit and TV set provided with the same |
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| Country | Link |
|---|---|
| CN (1) | CN201378416Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102122948A (en) * | 2010-01-11 | 2011-07-13 | 卡特彼勒公司 | Circuit device and method for processing digital signal |
| CN102543036A (en) * | 2011-12-14 | 2012-07-04 | 四川长虹电器股份有限公司 | Self-adaption adjusting method of display screen luminance |
| CN104249610A (en) * | 2014-09-09 | 2014-12-31 | 南京泰晟科技实业有限公司 | Automatic addressing apparatus of tire-pressure monitoring sensor |
-
2009
- 2009-02-23 CN CN200920144481U patent/CN201378416Y/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102122948A (en) * | 2010-01-11 | 2011-07-13 | 卡特彼勒公司 | Circuit device and method for processing digital signal |
| CN102122948B (en) * | 2010-01-11 | 2015-04-08 | 卡特彼勒公司 | Circuit device and method for processing digital signal |
| CN102543036A (en) * | 2011-12-14 | 2012-07-04 | 四川长虹电器股份有限公司 | Self-adaption adjusting method of display screen luminance |
| CN104249610A (en) * | 2014-09-09 | 2014-12-31 | 南京泰晟科技实业有限公司 | Automatic addressing apparatus of tire-pressure monitoring sensor |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100106 Termination date: 20130223 |