CN204650969U - A kind of mobile phone backlight LED drive circuit - Google Patents
A kind of mobile phone backlight LED drive circuit Download PDFInfo
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- CN204650969U CN204650969U CN201520389507.0U CN201520389507U CN204650969U CN 204650969 U CN204650969 U CN 204650969U CN 201520389507 U CN201520389507 U CN 201520389507U CN 204650969 U CN204650969 U CN 204650969U
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Abstract
The utility model discloses a kind of mobile phone backlight LED drive circuit, comprise power supply, backlight driving chip, booster circuit and LED backlight circuit, also comprise constant current input circuit, LED backlight circuit connects backlight driving chip and LED controls incoming end; The VIN end of backlight driving chip is connected with power supply, and LX end is connected with booster circuit, and EN end connects constant current input circuit, and FB end is connected with feedback circuit, and VOUT end is connected with overprotection circuit; The PWM waveform that PWM controller produces by the RC integration shaping circuit in the utility model carries out integration shaping, forms a galvanic current potential source; The stable DC voltage source obtained after the shaping of RC integration shaping circuit integration is carried out dividing potential drop current limliting and feedback by current constant control and feedback circuit, thus can be stable backlight driving chip is controlled, there will not be the phenomenon of quick-fried sudden strain of a muscle, certification of explosion protection can be passed through smoothly, and the security of the utility model circuit integrity is very high, FEEDBACK CONTROL is all very convenient with detection.
Description
Technical field
The utility model relates to LED drive circuit technical field, is specially a kind of mobile phone backlight LED drive circuit.
Background technology
Along with the development of electronics, the communication technology, the application of the communication terminals such as mobile phone in people's daily life is increasingly extensive; The leading application technologies such as high definition display, digital photographing, touch screen, GPS, intelligent chip lead the trend of mobile phone products, also driven the development of mobile communication industry, various multifunction intelligent mobile telephone, panel computer mobile phone, communication apparatus emerge in an endless stream.Therefore display screen is increasing also constantly gets consumer reception, and become the trend of mobile communication display screen development, intelligent mobile communication LED is developing to large scale.At present, main flow intelligent mobile communication equipment color screen LED backlight is all adopt high brightness light emitting diode LED to realize, along with the continuous increase of LED screen size, LED-backlit LED power consumption is also more and more higher, generally can reach 200 ~ 300 milliamperes, 1.0 ~ 1.5 watts, probably account for about 50% ~ 80% of whole intelligent communication electricity consumption of equipment, even higher.Obviously can not use safely under particular circumstances, therefore, the stable control inputs of neither one is difficult to pass through certification of explosion protection.
LED-backlit operationally needs the element of current stabilization, voltage stabilizing, but it is high that this class component should possess the dividing potential drop self born, but power consumption wants little characteristic, otherwise by making the LED-backlit with greater efficiency make the efficiency of overall system greatly reduce because the operating power consumption of driving circuit is too large, run counter to the aim of efficient energy-saving.So should not adopt resistance or serial regulating circuit to be used as the current limliting main circuit of LED backlight driver as far as possible, and electric capacity should be adopted, the efficient circuits such as inductance or active switched circuit, the high-level efficiency of such guarantee LED backlight system.What adopt that constant current source can be stable makes it luminous.
Most of backlight drive typical circuit generally selects pwm chip and current-limiting resistance to realize, and the time of lighting by controlling LED-backlit controls its brightness with the size flowing through electric current.Backlight drive circuit generally adopts following technology: pwm chip controls lighting time, is connected in series a current-limiting resistance, Current Control during conducting is realized backlight drive in the working range of LED-backlit; Due to the existence that PWM turns on and off, LED-backlit inevitably goes out first glimmers, and no matter be that can human eye identify, flicker is exist actually.
Utility model content
The purpose of this utility model is to provide a kind of mobile phone backlight LED drive circuit, to solve the problem proposed in above-mentioned background technology.
For achieving the above object, the utility model provides following technical scheme:
A kind of mobile phone backlight LED drive circuit, comprises power supply, backlight driving chip, booster circuit and LED backlight circuit, also comprises constant current input circuit, and LED backlight circuit connects backlight driving chip and LED controls incoming end; The VIN end of backlight driving chip is connected with power supply, and LX end is connected with booster circuit, and EN end connects constant current input circuit, and FB end is connected with feedback circuit, and VOUT end is connected with overprotection circuit, and GND holds ground connection; Described constant current input circuit connects PWM controller, specifically comprises RC integration shaping circuit and current constant control and feedback circuit; RC integration shaping circuit is made up of resistance R1 and electric capacity C2, one end of resistance R1 is connected with the output terminal of PWM controller, the other end of resistance R1 is connected with one end of electric capacity C2 and is connected with feedback circuit with current constant control, the other end ground connection of electric capacity C2, current constant control and feedback circuit include triode Q1 and resistance R3, the base stage of triode Q1 is connected with one end of resistance R1 and electric capacity C2, the collector of triode Q1 is held with the EN of backlight driving chip and is connected, the emitter of triode Q1 is connected with one end of resistance R3, the other end ground connection of resistance R3; Described booster circuit is made up of power inductance L1, diode D1, and be connected with LED backlight circuit, overprotection circuit comprises the electric capacity C4 and electric capacity C5 that are arranged in parallel, the COUT that one end of electric capacity C4 is connected to diode D1 and backlight driving chip holds, other end ground connection, electric capacity C5 one end is connected to diode D1 and LED and controls incoming end, and other end ground connection, with protection circuit; Feedback circuit comprises feedback resistance R4, and one end of feedback resistance R4 is connected with LED backlight circuit, other end ground connection.
As the utility model further technical scheme, described backlight driving chip is KTD251.
As the utility model further technical scheme, power inductance L1 is PSE25201B-4R7MS.
As the utility model further technical scheme, diode D1 is SBR140S3.
As the utility model further technical scheme, LED backlight circuit is in series with a current-limiting resistance RX, current-limiting resistance RX is variable resistor.
Compared with prior art, the PWM waveform that PWM controller produces by the RC integration shaping circuit in the utility model carries out integration shaping, forms a galvanic current potential source; The stable DC voltage source obtained after the shaping of RC integration shaping circuit integration is carried out dividing potential drop current limliting and feedback by current constant control and feedback circuit, realize current constant control and feedback, produce a predictable steady current, thus can be stable backlight driving chip is controlled, there will not be the phenomenon of quick-fried sudden strain of a muscle, can pass through certification of explosion protection smoothly, and the security of the utility model circuit integrity is very high, FEEDBACK CONTROL is all very convenient with detection.
Accompanying drawing explanation
Fig. 1 is the structural representation of a kind of mobile phone backlight LED drive circuit of the utility model.
Embodiment
Be described in more detail below in conjunction with the technical scheme of embodiment to this patent.
Refer to Fig. 1, a kind of mobile phone backlight LED drive circuit, comprises power supply, backlight driving chip, booster circuit and LED backlight circuit, also comprises constant current input circuit, and LED backlight circuit connects backlight driving chip and LED controls incoming end; The VIN end of backlight driving chip is connected with power supply, and LX end is connected with booster circuit, and EN end connects constant current input circuit, and FB end is connected with feedback circuit, and VOUT end is connected with overprotection circuit, and GND holds ground connection;
Described constant current input circuit connects PWM controller, and specifically comprise RC integration shaping circuit and current constant control and feedback circuit, described PWM controller produces the pwm pulse width adjustment waveform needed; The PWM waveform that PWM controller produces by RC integration shaping circuit carries out integration shaping, forms a galvanic current potential source; The stable DC voltage source obtained after the shaping of RC integration shaping circuit integration is carried out dividing potential drop current limliting and feedback by current constant control and feedback circuit, realizes current constant control and feedback, produces a steady current and is supplied to backlight driving chip; RC integration shaping circuit is made up of resistance R1 and electric capacity C2, one end of resistance R1 is connected with the output terminal of PWM controller, the other end of resistance R1 is connected with one end of electric capacity C2 and is connected with feedback circuit with current constant control, the other end ground connection of electric capacity C2, current constant control and feedback circuit include triode Q1 and resistance R3, the base stage of triode Q1 is connected with one end of resistance R1 and electric capacity C2, the collector of triode Q1 is held with the EN of backlight driving chip and is connected, the emitter of triode Q1 is connected with one end of resistance R3, the other end ground connection of resistance R3;
Described booster circuit is made up of power inductance L1, diode D1, and be connected with LED backlight circuit, to provide regulated output voltage, overprotection circuit comprises the electric capacity C4 and electric capacity C5 that are arranged in parallel, the COUT that one end of electric capacity C4 is connected to diode D1 and backlight driving chip holds, other end ground connection, and electric capacity C5 one end is connected to diode D1 and LED and controls incoming end, other end ground connection, with protection circuit; Feedback circuit comprises feedback resistance R4, and one end of feedback resistance R4 is connected with LED backlight circuit, other end ground connection, with the voltage in testing circuit.
Concrete, backlight driving chip of the present utility model is KTD251, and power inductance L1 is PSE25201B-4R7MS, and diode D1 is SBR140S3.
LED backlight circuit is in series with a current-limiting resistance RX, and current-limiting resistance RX is variable resistor.
Feedback control circuit, the voltage of feedback resistance R2 is detected by the FB end of backlight driving chip, export by the LX end of backlight driving chip and control booster circuit, make feedback resistance R2 voltage equal with the reference voltage of backlight driving chip inside, form closed-loop control, thus reach the object controlling LED working current.
Overvoltage crowbar, the VOUT of backlight driving chip holds the voltage of Detection capacitance C2, and controls booster circuit by control circuit, makes the output voltage of booster circuit more than 36V, can not prevent the too high damage backlight circuit of the output voltage of booster circuit.
The PWM waveform that PWM controller produces by RC integration shaping circuit carries out integration shaping, forms a galvanic current potential source; The stable DC voltage source obtained after the shaping of RC integration shaping circuit integration is carried out dividing potential drop current limliting and feedback by current constant control and feedback circuit, realize current constant control and feedback, produce a predictable steady current, thus can be stable backlight driving chip is controlled, there will not be the phenomenon of quick-fried sudden strain of a muscle, can pass through certification of explosion protection smoothly, and the security of the utility model circuit integrity is very high, FEEDBACK CONTROL is all very convenient with detection.
Above the better embodiment of this patent is explained in detail, but this patent is not limited to above-mentioned embodiment, in the ken that one skilled in the relevant art possesses, various change can also be made under the prerequisite not departing from this patent aim.
Claims (5)
1. a mobile phone backlight LED drive circuit, is characterized in that, comprises power supply, backlight driving chip, booster circuit and LED backlight circuit, also comprises constant current input circuit, and LED backlight circuit connects backlight driving chip and LED controls incoming end; The VIN end of backlight driving chip is connected with power supply, and LX end is connected with booster circuit, and EN end connects constant current input circuit, and FB end is connected with feedback circuit, and VOUT end is connected with overprotection circuit, and GND holds ground connection; Described constant current input circuit connects PWM controller, specifically comprises RC integration shaping circuit and current constant control and feedback circuit; RC integration shaping circuit is made up of resistance R1 and electric capacity C2, one end of resistance R1 is connected with the output terminal of PWM controller, the other end of resistance R1 is connected with one end of electric capacity C2 and is connected with feedback circuit with current constant control, the other end ground connection of electric capacity C2, current constant control and feedback circuit include triode Q1 and resistance R3, the base stage of triode Q1 is connected with one end of resistance R1 and electric capacity C2, the collector of triode Q1 is held with the EN of backlight driving chip and is connected, the emitter of triode Q1 is connected with one end of resistance R3, the other end ground connection of resistance R3; Described booster circuit is made up of power inductance L1, diode D1, and be connected with LED backlight circuit, overprotection circuit comprises the electric capacity C4 and electric capacity C5 that are arranged in parallel, the COUT that one end of electric capacity C4 is connected to diode D1 and backlight driving chip holds, other end ground connection, electric capacity C5 one end is connected to diode D1 and LED and controls incoming end, and other end ground connection, with protection circuit; Feedback circuit comprises feedback resistance R4, and one end of feedback resistance R4 is connected with LED backlight circuit, other end ground connection.
2. a kind of mobile phone backlight LED drive circuit according to claim 1, is characterized in that, described backlight driving chip is KTD251.
3. a kind of mobile phone backlight LED drive circuit according to claim 1, is characterized in that, diode D1 is SBR140S3.
4. a kind of mobile phone backlight LED drive circuit according to claim 1, is characterized in that, power inductance L1 is PSE25201B-4R7MS.
5. a kind of mobile phone backlight LED drive circuit according to claim 1, is characterized in that, LED backlight circuit is in series with a current-limiting resistance RX, and current-limiting resistance RX is variable resistor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520389507.0U CN204650969U (en) | 2015-06-06 | 2015-06-06 | A kind of mobile phone backlight LED drive circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520389507.0U CN204650969U (en) | 2015-06-06 | 2015-06-06 | A kind of mobile phone backlight LED drive circuit |
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| Publication Number | Publication Date |
|---|---|
| CN204650969U true CN204650969U (en) | 2015-09-16 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520389507.0U Expired - Fee Related CN204650969U (en) | 2015-06-06 | 2015-06-06 | A kind of mobile phone backlight LED drive circuit |
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| CN (1) | CN204650969U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110223617A (en) * | 2019-06-04 | 2019-09-10 | 惠州市力天科技有限公司 | A kind of control circuit and driving method of touch one-piece machine external equipment |
-
2015
- 2015-06-06 CN CN201520389507.0U patent/CN204650969U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110223617A (en) * | 2019-06-04 | 2019-09-10 | 惠州市力天科技有限公司 | A kind of control circuit and driving method of touch one-piece machine external equipment |
| CN110223617B (en) * | 2019-06-04 | 2023-06-27 | 惠州市力天科技有限公司 | Control circuit and driving method of external equipment of touch integrated machine |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20150916 Termination date: 20170606 |