CN102469666B - Feedback voltage stabilizing circuit - Google Patents
Feedback voltage stabilizing circuit Download PDFInfo
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- CN102469666B CN102469666B CN201010565840.4A CN201010565840A CN102469666B CN 102469666 B CN102469666 B CN 102469666B CN 201010565840 A CN201010565840 A CN 201010565840A CN 102469666 B CN102469666 B CN 102469666B
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Abstract
The invention provides a feedback voltage stabilizing circuit, which is used for providing the stable voltage for a multi-voltage output circuit so as to output multiple output voltages. The feedback voltage stabilizing circuit comprises a voltage control unit which is coupled among the output voltages and used for producing a first voltage according to the output voltages to transmit a voltage control signal. The feedback voltage stabilizing circuit further comprises a reference voltage generator which is coupled with the voltage control unit and used for receiving the voltage control signal to generate a reference voltage and feeding the reference voltage back to the multi-voltage output circuit.
Description
Technical field
The present invention is about a kind of monitoring (monitor) circuit, particularly about a kind of efficiency optimization (efficiency optimization) and error detection (fault detection) circuit of LED drive system.
Background technology
In view of the plurality of advantages of light-emitting diode (LED), for example volume is little, the reaction time is short, consumed power is low, reliability is high, a large amount of producing feasibility is high, so light-emitting diode is generally used in electronic installation and uses as light source.For example, using light-emitting diode as the backlight of liquid crystal display (LCD), to replace traditional fluorescent lamp.
The schematic diagram of Fig. 1 shows traditional LED drive system, and it mainly comprises multiple optical diode string (LED string) 10, (boost) controller 14 and boost power level (boost power stage) circuit 16 boost.
For the traditional LED drive system shown in Fig. 1, even if each light-emitting diodes pipe string 10 is used identical voltage source V--
dCand the light-emitting diode 100 of similar number, yet, owing to cannot mating completely between each light-emitting diode 100, thereby make the voltage of each input pad (input pad) 11 not identical.In order to reduce the power consumption of light-emitting diodes pipe string 10, thus in circuit design, the magnitude of voltage that meeting feed-in boost pressure controller 14 1 is subscribed, for example, 1 volt of voltage, as controlling voltage source V
dCbenchmark, then control voltage source V with the feedback circuit design of boost pressure controller 14 and boost power stage circuit 16
dC, make the voltage of input pad 11 can be stable at 1 volt of this scheduled voltage.
Yet above-mentioned design cannot reach desired accuracy.Therefore, often cannot reach the efficiency optimization of LED drive system.In addition, traditional LED drive system for example lacks a mechanism, with the inefficacy (fault) of monitoring light-emitting diodes pipe string 10, inefficacy short circuit or the open circuit of light-emitting diode 100.Therefore,, when there is 100 inefficacy of more serious light-emitting diode, the boost pressure controller 14 of traditional LED drive system and boost power stage circuit 16 cannot reach the efficiency optimization of light-emitting diode 100 especially.
Therefore, need the efficiency optimization and the error detection mechanism that propose a kind of novelty badly, effectively to monitor LED drive system, and promote its luminous efficiency.
Summary of the invention
In view of above-mentioned, the embodiment of the present invention discloses a kind of feedback voltage stabilizing circuit, applicable to LED drive system, except reducing the power consumption of LED drive system, can also monitor it and lose efficacy abnormal.
According to the embodiment of the present invention, feedback voltage stabilizing circuit provides voltage stabilizing in a multivoltage output circuit, and it exports a plurality of output voltages.Feedback voltage stabilizing circuit comprises voltage control unit and reference voltage generator.Wherein, voltage control unit is coupled to these output voltages, according to these output voltages, produces one first voltage and exports according to this voltage control signal.Reference voltage generator is coupled to voltage control unit, and receiver voltage control signal is also used generation one reference voltage, for feeding back to multivoltage output circuit.
Accompanying drawing explanation
The schematic diagram of Fig. 1 shows traditional LED drive system.
The schematic diagram of Fig. 2 shows the feedback voltage stabilizing circuit of the embodiment of the present invention.
Fig. 3 has shown the thin portion circuit diagram to digital voltage transducer (ADC) of simulating of Fig. 2.
Fig. 4 has shown the thin portion circuit diagram of the low pass filter of the embodiment of the present invention.
Fig. 5 has shown the boost pressure controller of the embodiment of the present invention and the thin portion circuit diagram of boost power stage circuit.
Main element symbol description
10 light-emitting diodes pipe strings
100 light-emitting diodes
11 input pads
14 boost pressure controllers
16 boost power stage circuit
2 modular circuits
20 multivoltage output circuits
21 simulate to digital voltage transducer (ADC)
210 multiplexers
212 simulate to digital voltage conversion (ADC) unit
22 voltage control units
220 logical blocks
23 reference voltage generators
232 signal generators
234 low pass filters (LPF)
24 boost pressure controllers
26 boost power stage circuit
V
dCvoltage source
I
scurrent source
R1/R2 divider resistance
R
lPFresistance
C
lPFelectric capacity
L inductance
C electric capacity
SW switching transistor
Embodiment
The schematic diagram of Fig. 2 shows the feedback voltage stabilizing circuit of the embodiment of the present invention, and it can provide voltage stabilizing in multivoltage output circuit 20, its exportable a plurality of output voltages.In the present embodiment, multivoltage output circuit 20 comprises multiple optical diode string (LED string) 10, and its brightness is controlled by respectively multiple current source I
s.Each light-emitting diodes pipe string 10 comprises a light-emitting diode 100 more than series connection, and the anodic bonding of light-emitting diodes pipe string 10 outermost end light-emitting diodes 100 is to voltage source V
dC, the negative electrode of light-emitting diodes pipe string 10 outermost end light-emitting diodes 100 is connected to the input pad (pad) 11 of modular circuit 2.Multivoltage output circuit 20 is applicable to LED drive system, the backlight module of liquid crystal display for example, but not as limit.
In the present embodiment, feedback voltage stabilizing circuit mainly comprises voltage control unit 22 and reference voltage generator 23.Wherein, voltage control unit 22 is coupled to these output voltages, according to these output voltages to produce the first voltage output voltage control signal according to this.In addition, reference voltage generator 23 is coupled to voltage control unit 22, and receiver voltage control signal is also used generation reference voltage, for feeding back to multivoltage output circuit 20.Above-mentioned voltage control unit 22 generally can integration and making in modular circuit 2, reference voltage generator 23 is made in outside modular circuit 2.Yet whether the above-mentioned square that respectively forms is made in same modular circuit, is determined by various application scenarios.
In addition, the feedback voltage stabilizing circuit of the present embodiment also can comprise simulates to digital voltage transducer (ADC) 21, and being connected in multivoltage output circuit 20 and changing these (simulation) output voltages is multiple digital voltage.These multivoltages are fed to voltage control unit 22, its select these digital voltages one of them as the first above-mentioned voltage.Fig. 3 shows the thin portion circuit diagram to digital voltage transducer (ADC) 21 of simulating of the embodiment of the present invention.In the present embodiment, simulate to digital voltage transducer (ADC) 21 and comprise multiplexer 210 and simulate to digital voltage conversion (ADC) unit 212.Wherein, multiplexer 210 receives the output voltage of many input pads 11, and one of them is to be fed to ADC unit 212 in each selection of time (or sampling).212 of ADC unit are converted to digital voltage by the selected output voltage of multiplexer 210.
In the present embodiment, voltage control unit 22 comprises logical block 220.Wherein, logical block 220 according to a preset rules select these digital voltages one of them as the first above-mentioned voltage, and export a corresponding voltage control signal.In different embodiment, according to different demands, may adopt different preset rules.For example, in the present embodiment, for promoting the efficiency of multivoltage output circuit 20, circuit can be designed to get minimum output voltage so that multivoltage output circuit institute consumed power minimizes.Therefore, logical block 220 selects the minimum voltage of these digital voltages as the first voltage.The enforcement of logical block 220 generally can be used hardware technology, software engineering or its combination.
Reference voltage generator 23 is connected in logical block 220.Reference voltage generator 23 comprises signal generator 232, and its voltage control signal producing according to the first voltage produces a waveform.In the present embodiment, signal generator 232 is pulse width modulating signal generator, and it produces different pulse durations according to voltage control signal.In one embodiment, logical block 220 is compared the first voltage with a target voltage, then produces voltage control signal so that signal generator 232 is adjusted pulse durations with both difference.In details of the words, signal generator 232 can be adjusted pulse duration according to the ratio equal proportion of this difference and target voltage.When reponse system reaches stable state, target voltage can be adjusted to and approach the first voltage.And one embodiment of the invention is adjusted the value of the first voltages by voltage control unit 22, and and then by reference voltage generator 23, produce reference voltages, allow target voltage follow the change of the first voltage and to adjust.Allow by this voltage source that multiple output circuit connects also and then adjust to reach systemic presupposition or ideal value.
The reference voltage generator 23 of the present embodiment also comprises a low pass filter (LPF) 234, for capture the part of direct voltage for the modulation waveform exported from signal generator 232, usings as with reference to voltage.Fig. 4 shows the thin portion circuit diagram of the low pass filter (LPF) 234 of the embodiment of the present invention, and it mainly comprises resistance R
lPFand capacitor C
lPF.Wherein, resistance R
lPFbe connected in the output of signal generator 232, and capacitor C
lPFbe connected in resistance R
lPFand between ground.
Reference voltage generator 23 is controlled by voltage control signal, adjustment by the work period, make the reference voltage of output also with works adjustment, and then the voltage source of multivoltage output circuit is adjusted, thereby allow the central minimum voltage of multi-output voltages can be stable at target voltage.
The feedback voltage stabilizing circuit of one embodiment of the invention also can comprise boost pressure controller 24 and boost power stage circuit 26.Fig. 5 shows the boost pressure controller 24 of the embodiment of the present invention and the thin portion circuit diagram of boost power stage circuit 26.Boost pressure controller 24 is for the reference voltage of relatively exporting from reference voltage generator 23 and the adjustable-voltage source V of multivoltage output circuit
dCthe voltage of a dividing point, and export according to this feedback control signal to boost power stage circuit 26.Boost power stage circuit 26 makes voltage source V according to feedback control signal
dCthe voltage approaches of dividing point in reference voltage, and then adjust this adjustable-voltage source V
dCmagnitude of voltage.The boost power stage circuit 26 of the present embodiment is for comprising switched-mode power supply for device (switching power supply), it mainly comprises N-type metal-oxide semiconductor (NMOS) switching transistor SW, and the accumulator being comprised of inductance L and/or capacitor C.NMOS switching transistor SW is controlled by voltage control signal to carry out the switching of power supply.
Except reaching the object of feedback regulation, the present embodiment also can be in order to carry out wrong detection.For example, when inefficacy short circuit occurs one or more light-emitting diode 100 of a certain light-emitting diodes pipe string 10, can there is abnormal rising in a certain voltage of the output voltage of its corresponding input pad 11.Logical block 220 can detect by monitoring 10 corresponding input pad 11 voltages of each light-emitting diodes pipe string the short circuit of a certain light-emitting diodes pipe string 10.In another example, when there is to lose efficacy open circuit in one or more light-emitting diode 100 of a certain light-emitting diodes pipe string 10, can there is abnormal reduction in the voltage of its corresponding input pad 11, logical block 220 can detect by monitoring 10 corresponding input pad 11 voltages of light-emitting diodes pipe string the inefficacy open circuit of light-emitting diodes pipe string 10.Detected inefficacy short circuit or open circuit can further offer other unit of system and do further to dispose.
The foregoing is only preferred embodiment of the present invention, not in order to limit claim of the present invention; All other do not depart from the equivalence completing under the spirit that invention discloses and changes or modify, and all should be included in the scope that claim limits.
Claims (9)
1. a feedback voltage stabilizing circuit, provides voltage stabilizing in a multivoltage output circuit, and this multivoltage output circuit comprises a plurality of light-emitting diodes pipe strings and exports a plurality of output voltages, and this feedback voltage stabilizing circuit comprises:
One voltage control unit, is coupled to these output voltages, according to these output voltages, produces one first voltage and exports according to this voltage control signal;
One reference voltage generator, is coupled to this voltage control unit, receives this voltage control signal and use to produce a reference voltage, for feeding back to this multivoltage output circuit;
One simulates to digital voltage transducer, is connected in this multivoltage output circuit and changes these output voltages into a plurality of digital voltages; Wherein this voltage control unit selects these digital voltage one as this first voltage; And
One logical block, according to a preset rules, select these digital voltage one and produce this voltage control signal as this first voltage and according to this first voltage, and monitor these digital voltages to detect short circuit or the open circuit that lost efficacy of each light-emitting diodes pipe string of this multivoltage output circuit.
2. feedback voltage stabilizing circuit as claimed in claim 1, it is characterized in that, this reference voltage generator comprises a signal generator, receive this voltage control signal and produce the output signal of a correspondence, wherein this signal generator is a pulse width modulating signal generator, adjusts a pulse duration of this output signal according to this voltage control signal.
3. feedback voltage stabilizing circuit as claimed in claim 2, is characterized in that, this logical block is compared this first voltage and produce this voltage control signal with a target voltage, and this signal generator is adjusted this pulse duration according to this.
4. feedback voltage stabilizing circuit as claimed in claim 3, is characterized in that, this logical block produces this voltage control signal according to a difference of this first voltage and this target voltage, for this signal generator, adjusts this pulse duration.
5. feedback voltage stabilizing circuit as claimed in claim 4, is characterized in that, this logical block selects a minimum voltage in these digital voltages as this first voltage.
6. feedback voltage stabilizing circuit as claimed in claim 4, is characterized in that, this logical block produces this voltage control signal according to the ratio equal proportion of this difference and this target voltage, and this signal generator is adjusted this pulse duration according to this.
7. feedback voltage stabilizing circuit as claimed in claim 2, is characterized in that, above-mentioned reference voltage generator also comprises:
One low pass filter, the part that this output signal captures a direct voltage is certainly as this reference voltage.
8. feedback voltage stabilizing circuit as claimed in claim 1, is characterized in that, above-mentioned simulation to digital voltage transducer comprises:
One multiplexer, it receives those output voltages, and in each selection of time one of them; And
One simulates to digital voltage converting unit, and the output voltage of this selection is converted to corresponding this digital voltage.
9. feedback voltage stabilizing circuit as claimed in claim 1, is characterized in that, also comprises:
One boost pressure controller, the dividing potential drop in an adjustable-voltage source of this reference voltage and this multivoltage output circuit relatively, and produce a feedback control signal; And
One boost power stage circuit, receives this feedback control signal and makes the voltage approaches of this dividing point in this reference voltage, so that corresponding this adjustable-voltage source to be provided.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010565840.4A CN102469666B (en) | 2010-11-17 | 2010-11-17 | Feedback voltage stabilizing circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201010565840.4A CN102469666B (en) | 2010-11-17 | 2010-11-17 | Feedback voltage stabilizing circuit |
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| Publication Number | Publication Date |
|---|---|
| CN102469666A CN102469666A (en) | 2012-05-23 |
| CN102469666B true CN102469666B (en) | 2014-01-29 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201010565840.4A Expired - Fee Related CN102469666B (en) | 2010-11-17 | 2010-11-17 | Feedback voltage stabilizing circuit |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI456880B (en) | 2012-11-19 | 2014-10-11 | Ind Tech Res Inst | Switch circuit |
| CN103488226B (en) * | 2013-09-09 | 2015-06-10 | 天脉聚源(北京)传媒科技有限公司 | Output voltage control circuit |
| JP6896215B2 (en) * | 2016-03-25 | 2021-06-30 | 株式会社アイテックシステム | A short-circuit abnormality detection device for an LED lighting system, an LED lighting device having the device, and a short-circuit abnormality detection method for an LED lighting system. |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101527989A (en) * | 2008-03-04 | 2009-09-09 | 原景科技股份有限公司 | Circuit and method for driving light emitting diodes |
| CN101583216A (en) * | 2008-05-16 | 2009-11-18 | 原景科技股份有限公司 | Driving circuit and driving method of light emitting diode (LED) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007035883A2 (en) * | 2005-09-20 | 2007-03-29 | California Micro Devices Corporation | Driving parallel strings of series connected leds |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101527989A (en) * | 2008-03-04 | 2009-09-09 | 原景科技股份有限公司 | Circuit and method for driving light emitting diodes |
| CN101583216A (en) * | 2008-05-16 | 2009-11-18 | 原景科技股份有限公司 | Driving circuit and driving method of light emitting diode (LED) |
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| CN102469666A (en) | 2012-05-23 |
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