CN101105583A - Pulse light modulation circuit - Google Patents
Pulse light modulation circuit Download PDFInfo
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- CN101105583A CN101105583A CNA2006100616127A CN200610061612A CN101105583A CN 101105583 A CN101105583 A CN 101105583A CN A2006100616127 A CNA2006100616127 A CN A2006100616127A CN 200610061612 A CN200610061612 A CN 200610061612A CN 101105583 A CN101105583 A CN 101105583A
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Abstract
The invention discloses a pulse light regulating circuit which comprises a pulse output circuit, a voltage division circuit, a calculation amplification circuit and an oscillation circuit; wherein the pulse output circuit generates square wave pulse signals; the square wave pulse signals are transmitted to a negative input end of the amplification circuit after being implemented voltage division by the voltage division circuit; the oscillation circuit generates direct current voltage signals which are transmitted to a positive input end of the calculation amplification circuit; after comparing the negative input end and the positive input end, the calculation amplification circuit outputs pulse light regulating signals.
Description
Technical field
The present invention relates to a kind of pulse light modulation circuit that is used for LCD.
Background technology
Because it is frivolous that LCD has, power consumption is hanged down and characteristics such as radiation is few, therefore is widely used in fields such as portable DVD player, visual music player, mobile phone and notebook computer.Because the liquid crystal molecule itself in the LCD is not luminous, therefore LCD needs to show to realize image by a module illumination backlight, common module backlight comprises a plurality of backlight lamp tubes and an inverted rectifier (Inverter), and this inverted rectifier converts direct current to alternating current and is used to drive this backlight lamp tube.Usually, the inverted rectifier of prior art comprises a pulse light modulation circuit, and it regulates the brightness of backlight lamp tube by changing the dutycycle of this alternating current that drives backlight lamp tube.
Seeing also Fig. 1, is a kind of circuit diagram of prior art pulse light modulation circuit.This pulse light modulation circuit 100 comprises an impulse output circuit 110, an integrating circuit 120, a bleeder circuit 130, an oscillatory circuit 140, an operational amplification circuit 150 and a mu balanced circuit 160.
This operational amplification circuit 150 comprises a positive input terminal, a negative input end and an output terminal.
This oscillatory circuit 140 comprises a LF oscillator 143 and an oscillating capacitance 141.This LF oscillator 143 is via these oscillating capacitance 141 ground connection.A circuit node is connected to the positive input terminal of this operational amplification circuit 150 between this LF oscillator 143 and this oscillating capacitance 141.This oscillating capacitance 141 is 4.7nF.
This impulse output circuit 110 comprises a convergent-divergent chip 111, a N channel enhancement MOS transistor 112, a biasing resistor 113 and a 5V direct supply 114.The source S ground connection of this N channel enhancement MOS transistor 112, drain D is connected to this 5V direct supply 114 via this biasing resistor 113, and grid G is connected to this convergent-divergent chip 111 and is used to receive the pulse control signal that this convergent-divergent chip 111 provides.
This integrating circuit 120 comprises an integrating resistor 121 and an integrating capacitor 122.The drain D of this N channel enhancement MOS transistor 112 connect this integrating resistor 121 and this integrating capacitor 122 back ground connection.This integrating resistor 121 is 47K Ω.This integrating capacitor 122 is 0.1 μ F.
This bleeder circuit 130 comprises two divider resistances 131,132.A circuit node this two divider resistance 131,132 back ground connection of connecting successively between this integrating resistor 121 and the integrating capacitor 122.A circuit node is connected to the negative input end of this operational amplification circuit 150 between this two divider resistance 131,132.This two divider resistance 131,132 is respectively 100K Ω, 47K Ω.
This mu balanced circuit 160 comprises a current-limiting resistance 161, a filter capacitor 162 and a 5V reference power source 163.This 5V reference power source 163 connect successively this current-limiting resistance 161 and this filter capacitor 162 back ground connection.A circuit node is connected to the negative input end of this operational amplification circuit 150 between this current-limiting resistance 161 and this filter capacitor 162.This current-limiting resistance 161 is 182K Ω.This filter capacitor 162 is 1nF.
The amplitude that this impulse output circuit 110 produces as shown in Figure 2 is the square-wave pulse signal of 5V.Become 1.5V d. c. voltage signal as shown in Figure 3 after this 5V square-wave pulse signal is handled via this integrating circuit 120, this bleeder circuit 130 and this mu balanced circuit 160 successively, and import the negative input end of this operational amplification circuit 150.The amplitude that this oscillatory circuit 140 produces as shown in Figure 4 is the triangular pulse signal of 1.6V, and imports the positive input terminal of this operational amplification circuit 150.Output one pulse light modulation signal behind the signal of these operational amplification circuit 150 its positive and negative two input ends of comparison.
In this pulse light modulation circuit 100, after needing to be handled by integrating circuit 120, this bleeder circuit 130 and this mu balanced circuit 160 successively, the 5V square-wave pulse signal that this impulse output circuit 110 produces just can be transferred to the negative input end of this operational amplification circuit 150, therefore interference in various degree can appear in this 5V square-wave pulse signal in transmission course, causes the pulse light modulation jitter of these pulse light modulation circuit 100 outputs.And, comprising this integrating circuit 120, this bleeder circuit 130 and this mu balanced circuit 160 in this pulse light modulation circuit 100, its circuit structure is complicated, and cost is higher.
Summary of the invention
In order to solve the complicated shortcoming of prior art pulse light modulation circuit structure, be necessary to provide a kind of structure more better simply pulse light modulation circuit.
A kind of pulse light modulation circuit, it comprises an impulse output circuit, a bleeder circuit, an operational amplification circuit and an oscillatory circuit.This impulse output circuit produces a square-wave pulse signal, this square-wave pulse signal is transferred to the negative input end of this operational amplification circuit after via this bleeder circuit dividing potential drop, this oscillatory circuit produces the positive input terminal that a direct current voltage signal is transferred to this operational amplification circuit, output one pulse light modulation signal behind the signal of these its positive and negative two input ends of operational amplification circuit comparison.
A kind of pulse light modulation circuit, it comprises an operational amplification circuit, an oscillatory circuit, an impulse output circuit and a bleeder circuit.This operational amplification circuit comprises a positive input terminal, a negative input end and an output terminal.This oscillatory circuit comprises a LF oscillator, an oscillating capacitance and an oscillation resistance.This impulse output circuit comprises a convergent-divergent chip, a N channel enhancement MOS transistor, a biasing resistor and a direct current power supply.This bleeder circuit comprises two divider resistances.Be connected between this LF oscillator and the ground after this oscillating capacitance and the oscillation resistance parallel connection.The source ground of this N channel enhancement MOS transistor, drain electrode is connected to this direct supply via this biasing resistor, and grid is connected to this convergent-divergent chip and is used to receive the pulse control signal that this convergent-divergent chip provides.The drain electrode of this N channel enhancement MOS transistor ground connection behind this two divider resistance of connecting successively, the circuit node between this two divider resistance is connected to the negative input end of this operational amplifier.Circuit node between this oscillation resistance and this LF oscillator is connected to the positive input terminal of this operational amplifier.Output one pulse light modulation signal behind the signal of these its positive and negative two input ends of operational amplification circuit comparison.
Compared to prior art, there are not integrating circuit and mu balanced circuit in the above-mentioned pulse light modulation circuit.Therefore the square-wave pulse signal of this impulse output circuit output can directly be transferred to this operational amplification circuit after via this bleeder circuit dividing potential drop, has reduced the interference that square-wave pulse signal occurs in transmission course.And because there is no integrating circuit and mu balanced circuit in this pulse light modulation circuit, so circuit structure is simpler, and cost is lower.
Description of drawings
Fig. 1 is a kind of circuit diagram of prior art pulse light modulation circuit.
Fig. 2 is that the amplitude that pulse light modulation circuit produces among Fig. 1 is the oscillogram of the square-wave pulse signal of 5V.
Fig. 3 is the oscillogram of the 1.5V d. c. voltage signal that pulse light modulation circuit produces among Fig. 1.
Fig. 4 is that the amplitude that pulse light modulation circuit produces among Fig. 1 is the oscillogram of the triangular pulse signal of 1.6V.
Fig. 5 is the circuit diagram of pulse light modulation circuit one better embodiment of the present invention.
Fig. 6 is that the amplitude that pulse light modulation circuit produces among Fig. 5 is the waveform synoptic diagram of the square-wave pulse signal of 5V.
Fig. 7 is that the amplitude that pulse light modulation circuit produces among Fig. 5 is the oscillogram of the square-wave pulse signal of 1.2V
Fig. 8 is the oscillogram of the 0.7V d. c. voltage signal that pulse light modulation circuit produces among Fig. 5.
Embodiment
Seeing also Fig. 5, is the circuit diagram of pulse light modulation circuit one better embodiment of the present invention.This pulse light modulation circuit 200 comprises an impulse output circuit 210, a bleeder circuit 230, an oscillatory circuit 240 and an operational amplification circuit 251.
This operational amplification circuit 251 comprises a positive input terminal, a negative input end and an output terminal.
This oscillatory circuit 240 comprises a LF oscillator 243, an oscillating capacitance 241 and an oscillation resistance 242.Be connected between this LF oscillator 243 and the ground after this oscillating capacitance 241 and oscillation resistance 242 parallel connections.Circuit node between this oscillation resistance 242 and this LF oscillator 243 is connected to the positive input terminal of this operational amplifier 251.This oscillating capacitance 241 is 4.7nF.This oscillation resistance 242 is 604K Ω.
This impulse output circuit 210 comprises a convergent-divergent chip 211, a N channel enhancement MOS transistor 212, a biasing resistor 213 and a 5V direct supply 214.The source S ground connection of this N channel enhancement MOS transistor 212, drain D is connected to this 5V direct supply 214 via this biasing resistor 213, and grid G is connected to this convergent-divergent chip 211 and is used to receive the pulse control signal that this convergent-divergent chip 211 provides.
This bleeder circuit 230 comprises two divider resistances 231,232.The drain D of this N channel enhancement MOS transistor 212 this two divider resistance 231,232 back ground connection of connecting successively.Circuit node between this two divider resistance 231,232 is connected to the negative input end of this operational amplifier 251.This two divider resistance 231,232 is respectively 22K Ω, 10K Ω.
The amplitude that this impulse output circuit 210 produces as shown in Figure 6 is the square-wave pulse signal of 5V, and is exported by the drain D of this N channel enhancement MOS transistor 212.The amplitude that this 5V square-wave pulse signal becomes as shown in Figure 7 after via these bleeder circuit 230 dividing potential drops is the square-wave pulse signal of 1.2V, and is transferred to the negative input end of this operational amplification circuit 251.
The 0.7V d. c. voltage signal that this oscillatory circuit 240 produces as shown in Figure 8, and be transferred to the positive input terminal of this operational amplification circuit 251.Output one pulse light modulation signal behind the signal of these operational amplification circuit 251 its positive and negative two input ends of comparison.
There are not integrating circuit and mu balanced circuit in this pulse light modulation circuit 200.Therefore the 5V square-wave pulse signal of these impulse output circuit 210 outputs can directly be transferred to this operational amplification circuit 251 after via these bleeder circuit 230 dividing potential drops, has reduced the interference that square-wave pulse signal occurs in transmission course.That is, this operational amplification circuit 251 can be exported a pulse light modulation signal according to the pulse control signal that this convergent-divergent chip 211 provides.And because do not have integrating circuit and mu balanced circuit in this pulse light modulation circuit 200, so circuit structure is simpler, and cost is lower.
Claims (10)
1. pulse light modulation circuit, it comprises:
One impulse output circuit;
One bleeder circuit;
One operational amplification circuit; With
One oscillatory circuit;
It is characterized in that: this impulse output circuit produces a square-wave pulse signal, this square-wave pulse signal is transferred to the negative input end of this operational amplification circuit after via this bleeder circuit dividing potential drop, this oscillatory circuit produces the positive input terminal that a direct current voltage signal is transferred to this operational amplification circuit, output one pulse light modulation signal behind the signal of these its positive and negative two input ends of operational amplification circuit comparison.
2. pulse light modulation circuit as claimed in claim 1 is characterized in that: the amplitude of this square-wave pulse signal is 5V.
3. pulse light modulation circuit as claimed in claim 2 is characterized in that: this bleeder circuit comprises two divider resistances, and this bleeder circuit is that the square-wave pulse signal dividing potential drop of 5V is that amplitude is the square-wave pulse signal of 1.2V with this amplitude.
4. pulse light modulation circuit as claimed in claim 3 is characterized in that: this two divider resistances size is respectively 22K Ω, 10K Ω.
5. pulse light modulation circuit as claimed in claim 1, it is characterized in that: this oscillatory circuit comprises a LF oscillator, one oscillating capacitance and an oscillation resistance, be connected between this LF oscillator and the ground after this oscillating capacitance and this oscillation resistance parallel connection, the circuit node between this oscillation resistance and this LF oscillator is connected to the positive input terminal of this operational amplification circuit.
6. pulse light modulation circuit as claimed in claim 5 is characterized in that: this oscillating capacitance is 4.7nF.
7. pulse light modulation circuit as claimed in claim 5 is characterized in that: this oscillation resistance is 604K Ω.
8. pulse light modulation circuit as claimed in claim 1, it is characterized in that: this impulse output circuit comprises a convergent-divergent chip, one N channel enhancement MOS transistor, one biasing resistor and a 5V direct supply, the source ground of this N channel enhancement MOS transistor, drain electrode is connected to this 5V direct supply via this biasing resistor, and grid is connected to this convergent-divergent chip and is used to receive the pulse control signal that this convergent-divergent chip produces.
9. pulse light modulation circuit as claimed in claim 8 is characterized in that: the drain electrode of this N channel enhancement MOS transistor is connected to this bleeder circuit, and exports this square-wave pulse signal.
10. pulse light modulation circuit, it comprises:
One operational amplification circuit, it comprises a positive input terminal, a negative input end and an output terminal;
One oscillatory circuit, it comprises a LF oscillator, one oscillating capacitance and an oscillation resistance are connected between this LF oscillator and the ground after this oscillating capacitance and the oscillation resistance parallel connection, and the circuit node between this oscillation resistance and this LF oscillator is connected to the positive input terminal of this operational amplifier;
One impulse output circuit, this impulse output circuit comprises a convergent-divergent chip, one N channel enhancement MOS transistor, one biasing resistor and a direct current power supply, the source ground of this N channel enhancement MOS transistor, drain electrode is connected to this direct supply via this biasing resistor, and grid is connected to this convergent-divergent chip and is used to receive the pulse control signal that this convergent-divergent chip provides; With
One bleeder circuit, it comprises two divider resistances, the drain electrode of this N channel enhancement MOS transistor ground connection behind this two divider resistance of connecting successively, the circuit node between this two divider resistance is connected to the negative input end of this operational amplifier;
It is characterized in that: this impulse output circuit produces a square-wave pulse signal, this square-wave pulse signal is transferred to the negative input end of this operational amplification circuit after via this bleeder circuit dividing potential drop, this oscillatory circuit produces the positive input terminal that a direct current voltage signal is transferred to this operational amplification circuit, output one pulse light modulation signal behind the signal of these its positive and negative two input ends of operational amplification circuit comparison.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200610061612A CN100582877C (en) | 2006-07-12 | 2006-07-12 | Pulse light modulation circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200610061612A CN100582877C (en) | 2006-07-12 | 2006-07-12 | Pulse light modulation circuit |
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| Publication Number | Publication Date |
|---|---|
| CN101105583A true CN101105583A (en) | 2008-01-16 |
| CN100582877C CN100582877C (en) | 2010-01-20 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200610061612A Expired - Fee Related CN100582877C (en) | 2006-07-12 | 2006-07-12 | Pulse light modulation circuit |
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| CN (1) | CN100582877C (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102497203A (en) * | 2011-12-02 | 2012-06-13 | 武汉纺织大学 | Phase-locked subdivision method for displacement detection |
| CN103475189A (en) * | 2013-08-28 | 2013-12-25 | 中国航天科技集团公司第九研究院第七七一研究所 | Oscillator of PWM (pulse-width modulation) controller |
| WO2014131201A1 (en) * | 2013-02-26 | 2014-09-04 | 深圳市华星光电技术有限公司 | Backlight dimming circuit, dimming method thereof and liquid crystal display |
-
2006
- 2006-07-12 CN CN200610061612A patent/CN100582877C/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102497203A (en) * | 2011-12-02 | 2012-06-13 | 武汉纺织大学 | Phase-locked subdivision method for displacement detection |
| WO2014131201A1 (en) * | 2013-02-26 | 2014-09-04 | 深圳市华星光电技术有限公司 | Backlight dimming circuit, dimming method thereof and liquid crystal display |
| CN103475189A (en) * | 2013-08-28 | 2013-12-25 | 中国航天科技集团公司第九研究院第七七一研究所 | Oscillator of PWM (pulse-width modulation) controller |
| CN103475189B (en) * | 2013-08-28 | 2015-11-18 | 中国航天科技集团公司第九研究院第七七一研究所 | A kind of oscillator of PWM controller |
Also Published As
| Publication number | Publication date |
|---|---|
| CN100582877C (en) | 2010-01-20 |
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Granted publication date: 20100120 Termination date: 20180712 |