CN106601182A - Light-emitting diode backlight drive circuit - Google Patents
Light-emitting diode backlight drive circuit Download PDFInfo
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- CN106601182A CN106601182A CN201510664869.0A CN201510664869A CN106601182A CN 106601182 A CN106601182 A CN 106601182A CN 201510664869 A CN201510664869 A CN 201510664869A CN 106601182 A CN106601182 A CN 106601182A
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Abstract
The invention provides a light-emitting diode backlight drive circuit used for driving a light-emitting diode circuit. The light-emitting diode backlight drive circuit comprises a reference voltage module, a chopper amplifier, a filter resistor, a compensation capacitor, a compensation resistor and a pulse width modulation module. The reference voltage module is used for providing a reference voltage. The chopper amplifier is used for outputting a first signal through an output end thereof with a reference voltage and a feedback voltage of the light-emitting diode circuit as an input. The filter resistor, the compensation capacitor and the compensation resistor are connected in series with the output end of the chopper amplifier, so that the first signal passes through a filter circuit to generate a second signal, wherein the filter circuit is composed of the filter resistor, the compensation capacitor and the compensation resistor. The pulse width modulation module is used for receiving the second signal and supplying a drive signal corresponding to the second signal and used for driving the light-emitting diode circuit.
Description
Technical field
The present invention relates to a kind of light-emitting diode backlight drive circuit, espespecially a kind of light-emitting diode backlight drive circuit for being applied to driven for emitting lights diode circuit.
Background technology
Market now has commonly used light emitting diode (LED) backlight on the display floater of various sizes, particularly applies on the small-medium size display floater of portable consumption electronic product.But consumer is also more and more stricter to the prescription of image, this requires that LED-backlit can in a wide range realize linearity light adjusting, and in general pulse width modulation (PWM) linearity light adjusting mode, due to the intrinsic imbalance of amplifier, it is difficult to accomplish that 2% depth below is dimmed, this can not increasingly meet demand of the consumer for product.
Fig. 1 is refer to, Fig. 1 is existing light-emitting diode backlight drive circuit.The electric current for flowing through circuit of LED LEDs passes through RFBResistance produces feedback voltage, and Jing after error amplifier EA amplifications, the input and sampled voltage as PWM comparator COMP is compared the difference of itself and chip internal reference voltage, the closing of power tube is controlled, so as to realize circuit of LED LEDs constant-current driving.
When PWM is dimmed, the reference voltage of the chip internal can change as PWM dims dutycycle (duty cycle) change of (dimming) signal, when duty cycle drop to 5% or so, the internal reference voltage is in 10 millivolts (mV) left and right, but in 5mV or so, the scope of such output current is (10+5) mV/R to the offset voltage of general error amplifier EAFBTo (10-5) mV/RFB, when duty cycle continue to reduce, the internal reference voltage is further reduced, and when the offset voltage of the internal reference voltage and error amplifier EA is suitable, output current may be the failure of zero, PWM dimming functions.As can be seen from the above analysis, the light modulation for reaching more depth is wanted, it is necessary to reduce the offset voltage of error amplifier EA.
Therefore, the offset voltage of amplifier how is reduced, so as to increase the light-emitting diode backlight drive circuit of depth dimming scope, as each dealer problem urgently to be resolved hurrily.
The content of the invention
In view of the disadvantages of known techniques, the main object of the present invention, it is that the structure that a kind of offset voltage that can reduce amplifier can apply to light-emitting diode backlight drive circuit again is provided, so as to increase the light-emitting diode backlight drive circuit of depth dimming scope
In order to achieve the above object and other purposes, the present invention provides a kind of light-emitting diode backlight drive circuit then, driven for emitting lights diode circuit is applied to, the light-emitting diode backlight drive circuit includes reference voltage module, chopper amplifier, filter resistance, compensating electric capacity, compensation resistance and Pulse width modulation module.The reference voltage module is used to provide reference voltage；The chopper amplifier, using the reference voltage and the feedback voltage for taking from the circuit of LED as input, and sends the first signal of output by outfan；The filter resistance, compensating electric capacity and compensation resistance, are serially connected with the outfan of the chopper amplifier, and with the filter circuit for making first signal pass through the filter resistance, compensating electric capacity and compensation resistance composition secondary signal is produced；And the Pulse width modulation module, the secondary signal is received, and provide the corresponding drive signal to drive the circuit of LED according to the secondary signal.
Compared to known techniques, because the light-emitting diode backlight drive circuit of the present invention replaces error amplifier general in prior art with chopper amplifier, the offset voltage of the chopper amplifier is typically in 200 microvolts (uV) left and right, much smaller than the offset voltage (5mV or so) of general error amplifier, therefore the light-emitting diode backlight drive circuit of the present invention can reach the light modulation of more depth, in addition, the filter resistance concatenated because of the filtering demands of the chopper amplifier output, the stability of loop is nor affected on, the disappearance of prior art is sufficiently addressed.
Description of the drawings
Fig. 1 is the configuration diagram of existing light-emitting diode backlight drive circuit.
Fig. 2 is the configuration diagram of the light-emitting diode backlight drive circuit embodiment of the present invention.
Symbol description：
LEDs circuit of LED
RFB resistance
EA error amplifiers
1 light-emitting diode backlight drive circuit
VR1 reference voltage modules
CEA1 chopper amplifiers
R1 filter resistances
P1 Pulse width modulation modules
Cc compensating electric capacities
Rc compensates resistance
Specific embodiment
Hereinafter embodiments of the present invention are illustrated by particular specific embodiment, those skilled in the art can easily be understood other advantages and effect of the present invention by content disclosed in the present specification.The present invention also can be implemented or applied by other different specific embodiments.
Fig. 2 is referred to, to understand the function mode of light-emitting diode backlight drive circuit of the present invention.As shown in the figure, the light-emitting diode backlight drive circuit 1 of the present invention, driven for emitting lights diode circuit LEDs is applied to, light-emitting diode backlight drive circuit 1 includes reference voltage module VR1, chopper amplifier CEA1, filter resistance R1, compensating electric capacity Cc, compensation resistance Rc and Pulse width modulation module P1.
Reference voltage module VR1 is used to provide reference voltage；Chopper amplifier CEA1, using the reference voltage and the feedback voltage for taking from circuit of LED LEDs as input, and sends the first signal of output by outfan；Filter resistance R1, compensating electric capacity Cc and compensation resistance Rc, are serially connected with the outfan of twt amplifier CEA1, and with the filter circuit for making first signal pass through filter resistance R1, compensating electric capacity Cc and compensation resistance Rc compositions secondary signal is produced；And Pulse width modulation module R1, the secondary signal is received, and provide the corresponding drive signal to driven for emitting lights diode circuit LEDs according to the secondary signal.
In an embodiment, the light-emitting diode backlight drive circuit 1 of the present invention instead of the general error amplifier that prior art is used with chopper amplifier CEA1, although chopper amplifier CEA1 can in All Time normal work, but output will have filtering to obtain a more stable value, so that other circuits are used, therefore, the outfan in chopper amplifier CEA1 has concatenated filter resistance R1.Because the offset voltage of chopper amplifier CEA1 is typically in 200uV or so, much smaller than the offset voltage (5mV or so) of general error amplifier, therefore the light-emitting diode backlight drive circuit 1 of the present invention may achieve the light modulation of more depth, for example, may achieve the 2% depth below light modulation that prior art is difficult to.
In further embodiment, filter resistance R1 is to be serially connected with the outfan of chopper amplifier CEA1 in order to chopper amplifier CEA1 outputs need filtering, and wherein filter resistance R1, compensating electric capacity Cc and compensation resistance Rc can form low-frequency filter circuit to meet demand, and filter resistance R1 has no effect on the stability of overall loop.
Compared to known techniques, because the light-emitting diode backlight drive circuit of the present invention replaces error amplifier general in prior art with chopper amplifier, the offset voltage of the chopper amplifier is typically in 200uV or so, much smaller than the offset voltage (5mV or so) of general error amplifier, therefore the light-emitting diode backlight drive circuit of the present invention can reach the light modulation of more depth, in addition, the filter resistance concatenated in response to the filtering demands of the chopper amplifier output, the stability of loop is nor affected on, the disappearance of prior art is sufficiently addressed.
By the description of above preferred embodiment, one skilled in the art when can the more clear present invention feature and spirit, only above-described embodiment principle only to illustrate the invention and its effect, and be not used to limit the present invention.Therefore, any modification carried out to above-described embodiment and change are without departing from spirit of the invention, and the interest field of the present invention should be as listed by claims.
Claims (2)
1. a kind of light-emitting diode backlight drive circuit, is applied to driven for emitting lights diode circuit, it is characterised in that include：
Reference voltage module, for providing reference voltage；
Chopper amplifier, using the reference voltage and the feedback voltage for taking from the circuit of LED as input, and by
Outfan sends the first signal of output；
Filter resistance, compensating electric capacity and compensation resistance, are serially connected with the outfan of the chopper amplifier, to make first signal
Secondary signal is produced by the filter circuit of the filter resistance, compensating electric capacity and compensation resistance composition；And
Pulse width modulation module, receives the secondary signal, and provides corresponding to drive this according to the secondary signal
The drive signal of circuit of LED.
2. light-emitting diode backlight drive circuit as claimed in claim 1, it is characterised in that the filter resistance, the compensating electric capacity with
And the filter circuit that compensation resistance is constituted is low-frequency filter circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510664869.0A CN106601182A (en) | 2015-10-15 | 2015-10-15 | Light-emitting diode backlight drive circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201510664869.0A CN106601182A (en) | 2015-10-15 | 2015-10-15 | Light-emitting diode backlight drive circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN106601182A true CN106601182A (en) | 2017-04-26 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201510664869.0A Pending CN106601182A (en) | 2015-10-15 | 2015-10-15 | Light-emitting diode backlight drive circuit |
Country Status (1)
| Country | Link |
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| CN (1) | CN106601182A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107148121A (en) * | 2017-06-30 | 2017-09-08 | 苏州菲达旭微电子有限公司 | A kind of chop control linear switch constant current and constant power circuit |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101170850A (en) * | 2006-10-25 | 2008-04-30 | 中华映管股份有限公司 | Light source driving circuit |
| CN201623900U (en) * | 2010-03-09 | 2010-11-03 | Bcd半导体制造有限公司 | Drive circuit for parallel light emitting diode |
| CN102117599A (en) * | 2010-01-05 | 2011-07-06 | 台达电子工业股份有限公司 | Backlight drive circuit suitable for liquid crystal display panel |
| CN202258258U (en) * | 2011-07-25 | 2012-05-30 | 深圳市华星光电技术有限公司 | Led backlight drive circuit |
| CN103474030A (en) * | 2013-09-11 | 2013-12-25 | 深圳市瀚强科技有限公司 | Isolation LED backlight driving circuit and LED displaying device |
-
2015
- 2015-10-15 CN CN201510664869.0A patent/CN106601182A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101170850A (en) * | 2006-10-25 | 2008-04-30 | 中华映管股份有限公司 | Light source driving circuit |
| CN102117599A (en) * | 2010-01-05 | 2011-07-06 | 台达电子工业股份有限公司 | Backlight drive circuit suitable for liquid crystal display panel |
| CN201623900U (en) * | 2010-03-09 | 2010-11-03 | Bcd半导体制造有限公司 | Drive circuit for parallel light emitting diode |
| CN202258258U (en) * | 2011-07-25 | 2012-05-30 | 深圳市华星光电技术有限公司 | Led backlight drive circuit |
| CN103474030A (en) * | 2013-09-11 | 2013-12-25 | 深圳市瀚强科技有限公司 | Isolation LED backlight driving circuit and LED displaying device |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107148121A (en) * | 2017-06-30 | 2017-09-08 | 苏州菲达旭微电子有限公司 | A kind of chop control linear switch constant current and constant power circuit |
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| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20170426 |
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| RJ01 | Rejection of invention patent application after publication |