CN208173205U - A kind of device removing display backlight circuit pwm noise - Google Patents
A kind of device removing display backlight circuit pwm noise Download PDFInfo
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- CN208173205U CN208173205U CN201820894704.1U CN201820894704U CN208173205U CN 208173205 U CN208173205 U CN 208173205U CN 201820894704 U CN201820894704 U CN 201820894704U CN 208173205 U CN208173205 U CN 208173205U
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- display backlight
- resistance
- pwm
- noise
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Abstract
The utility model discloses a kind of devices for removing display backlight circuit pwm noise, belong to display backlight field of circuit technology, device is applied in display backlight circuit, for filtering out the low-frequency noise of switching tube of the PWM waveform through oversampling circuit when；Device includes two and filters out unit, and each unit includes two resistance, and wherein in circuit, second resistance is grounded to form bleeder circuit for first resistor series connection.Compared to the prior art a kind of device of removal display backlight circuit pwm noise of the utility model, the noise under some specific frequency is eliminated when display backlight circuit is adjusted, can also improve the working efficiency of switching tube, reduces calorific value.
Description
Technical field
The utility model relates to display backlight field of circuit technology, specifically a kind of removal display backlight circuit pwm
The device of noise.
Background technique
PWM（Pulse width modulation）It is non-come the one kind controlled analog circuit using the numeral output of microprocessor
Normal effective technology is widely used in from measurement, communicates into many fields of power control and transformation.Pulse width is modulated
A kind of analog control mode, according to the variation of respective loads come the biasing of modulation transistor base stage or metal-oxide-semiconductor grid, to realize
The change of transistor or metal-oxide-semiconductor turn-on time, to realize the change of switching power supply output.This mode can make power supply
Output voltage is kept constant in operation conditions change.PWM is with it controls the corresponding good advantage of simple, flexible and dynamic and becomes
The most widely used control mode of power electronic technique.But worked in display backlight circuit in specific frequency, it can send out
The noise that human ear can be allowed to hear out.
Summary of the invention
The technical task of the utility model is to provide it is a kind of improve switching tube working efficiency,
Reduce a kind of device of removal display backlight circuit pwm noise of calorific value.
Technical solution adopted by the utility model to solve its technical problems is：A kind of removal display backlight circuit pwm makes an uproar
The device of sound, device are applied in display backlight circuit, and the low frequency for filtering out switching tube of the PWM waveform through oversampling circuit when is made an uproar
Sound；Unit is filtered out including two, each unit includes two resistance, and wherein in circuit, second resistance connects for first resistor series connection
Ground forms bleeder circuit.
Further, preferred structure is that the unit that filters out further includes a capacitor as filtering bypass, described
Capacitor one end connection first resistor output end, capacitor the other end ground connection.
Further, preferred structure is, device applies the input terminal in backlight circuit power supply pwm signal, described two
A unit that filters out is connected on two pwm signal lines of input terminal.
Further, preferred structure is that the first resistor is series resistance, and the Standard resistance range of first resistor is
The Europe 10-100；The second resistance is ground resistance, and the Standard resistance range of the second resistance is 2.2 kilo-ohms to 4.4 kilo-ohms.
A kind of device of the removal display backlight circuit pwm noise of the utility model compared to the prior art, beneficial effect
It is as follows：
1, by improving the Vpp of signal under specific frequency, make the edge of switching tube smooth waveform in rapid operation, i.e.,
Make the working efficiency that can also guarantee switch in high-load situations, this.
2, two resistance R55, R58, one for filtering out unit connect in circuit, and a ground connection forms bleeder circuit, when
PWM waveform low-frequency noise of meeting switch tube after the circuit is tentatively filtered out, and can stablize the frequency of the waveform；
3, the capacitor C41 for filtering out unit primarily serves filtering bypass effect, by the energy storage of capacitor come correction waveform
Edge, to keep waveform smoother more stable；
4, when signal does not pass through the circuit, the coarse fluctuation of waveform is very big, by filtering after switching tube amplification
Inductance will result in the noise that can be heard.When signal passes through the circuit, wave-like flat is smooth, does not have by switching tube and inductance
Have and hear noise, and switch efficiency improves, and reduces calorific value；
5, certain can be eliminated when display backlight circuit is adjusted by using the device of the utility model by verifying
Noise under a specific frequency can also improve the working efficiency of switching tube, reduce calorific value.
Detailed description of the invention
The present invention will be further described with reference to the accompanying drawing.
Attached drawing 1 is a kind of circuit diagram of device for removing display backlight circuit pwm noise；
Attached drawing 2 is the output waveform of display backlight circuit when not increasing the present apparatus；
Attached drawing 3 is the output waveform of display backlight circuit after increasing the present apparatus.
Specific embodiment
The utility model is described in further detail in the following with reference to the drawings and specific embodiments.
When we are in adjusting backlight luminance, when reaching some brightness value, PWM frequency work to human auditory system range
It is interior, ear-piercing sound can be issued.Because the energy comparison of load requirement is high, has no idea to change its working frequency, can only improve
The quality of waveform.After signal passes through the circuit, problem is resolved.The utility model discloses a kind of removal display backlights
The method of PWM noise in circuit will not send out the noise that seller can hear even if it works when specific frequency.
Embodiment 1：
A kind of device of removal display backlight circuit pwm noise of the utility model, device are applied to display backlight circuit
In, for filtering out the low-frequency noise of switching tube of the PWM waveform through oversampling circuit when；Unit is filtered out including two, device, which is applied, to be carried on the back
The input terminal of optical circuit power supply pwm signal, described two filter out two pwm signal lines that unit is connected to input terminal
On, each unit includes two resistance, and first unit includes R55, R58；Second unit includes R56, R57；Wherein first
Resistance（R55/ R56）It connects in circuit, second resistance（R57/ R58）Ground connection forms bleeder circuit.The first resistor
For series resistance, the Standard resistance range of first resistor is the Europe 10-100；The second resistance is ground resistance, the second resistance
Standard resistance range be 2.2 kilo-ohms to 4.4 kilo-ohms.When the low-frequency noise of meeting switch tube carries out just PWM waveform after the circuit
Step filters out, and can stablize the frequency of the waveform.
The unit that filters out further includes a capacitor as filtering bypass（C40/ C41）, described capacitor one end connects
Connect the output end of first resistor, the other end ground connection of capacitor.C40/C41 primarily serves filtering bypass effect, passes through capacitor
Energy storage comes the edge of correction waveform, to keep waveform smoother more stable.
As shown in Fig. 2：When signal does not pass through the circuit, the coarse fluctuation of waveform is very big, amplifies it by switching tube
It will result in the noise that can be heard by filter inductance afterwards.
As shown in Fig. 3：When signal passes through the circuit, wave-like flat is smooth, does not listen by switching tube and inductance
To noise, and switch efficiency improves, and reduces calorific value.
By verifying, method described in this patent is rationally effective.By using the method for the utility model, can show
Screen backlight circuit eliminates the noise under some specific frequency when adjusting, can also improve the working efficiency of switching tube, reduces calorific value.
The technical personnel in the technical field can readily realize the utility model with the above specific embodiments,.But
It is it should be appreciated that the utility model is not limited to the specific embodiments described above.On the basis of the disclosed embodiments,
The technical personnel in the technical field can arbitrarily combine different technical features, to realize different technical solutions.
Claims (4)
1. a kind of device for removing display backlight circuit pwm noise, which is characterized in that device is applied in display backlight circuit,
For filtering out the low-frequency noise of switching tube of the PWM waveform through oversampling circuit when；Unit is filtered out including two, each unit includes two
Resistance, wherein in circuit, second resistance is grounded to form bleeder circuit for first resistor series connection.
2. a kind of device for removing display backlight circuit pwm noise according to claim 1, which is characterized in that described
Filtering out unit further includes a capacitor as filtering bypass, the output end of capacitor one end connection first resistor, capacitor
The other end ground connection.
3. a kind of device for removing display backlight circuit pwm noise according to claim 1, which is characterized in that device is answered
Used in the input terminal of backlight circuit power supply pwm signal, described two filter out two PWM letter that unit is connected to input terminal
On number line.
4. a kind of device for removing display backlight circuit pwm noise according to claim 1, which is characterized in that described
First resistor is series resistance, and the Standard resistance range of first resistor is the Europe 10-100；The second resistance is ground resistance, described
The Standard resistance range of second resistance is 2.2 kilo-ohms to 4.4 kilo-ohms.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820894704.1U CN208173205U (en) | 2018-06-11 | 2018-06-11 | A kind of device removing display backlight circuit pwm noise |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820894704.1U CN208173205U (en) | 2018-06-11 | 2018-06-11 | A kind of device removing display backlight circuit pwm noise |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208173205U true CN208173205U (en) | 2018-11-30 |
Family
ID=64365830
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820894704.1U Active CN208173205U (en) | 2018-06-11 | 2018-06-11 | A kind of device removing display backlight circuit pwm noise |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN208173205U (en) |
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2018
- 2018-06-11 CN CN201820894704.1U patent/CN208173205U/en active Active
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