CN101814843A - Power supply system - Google Patents
Power supply system Download PDFInfo
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- CN101814843A CN101814843A CN200910105488A CN200910105488A CN101814843A CN 101814843 A CN101814843 A CN 101814843A CN 200910105488 A CN200910105488 A CN 200910105488A CN 200910105488 A CN200910105488 A CN 200910105488A CN 101814843 A CN101814843 A CN 101814843A
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- 238000006243 chemical reaction Methods 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims abstract description 7
- 230000005669 field effect Effects 0.000 claims description 12
- 239000003990 capacitor Substances 0.000 claims description 9
- 238000001914 filtration Methods 0.000 claims description 7
- 238000010586 diagram Methods 0.000 description 4
- 239000004973 liquid crystal related substance Substances 0.000 description 4
- 238000004804 winding Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 3
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
The invention relates to a power supply system which comprises a rectifying circuit, a light tube drive circuit and a control system power supply circuit, wherein the rectifying circuit is connected to an external alternating current power supply and used for converting an external electrical signal provided by the alternating current power supply into a first electrical signal; the light tube drive circuit comprises a single-stage power factor correcting circuit, a current converter circuit and a current balancing circuit; the single-stage power factor correcting circuit is connected to the rectifying circuit and used for enabling the first electrical signal to form a second electrical signal after power factor correction and direct current/direct current conversion; the current converter circuit is connected to the single-stage power factor correcting circuit and used for converting the second electrical signal into an alternating current voltage signal which can drive a plurality of light tubes; and the current balancing circuit is used for balancing the current among all the light tubes. The power supply system provided by the invention integrates the power factor correcting circuit and a direct current/direct current converting circuit, reduces the frequency of energy conversion and effectively reduces the power loss in the switching process of a power supply.
Description
Technical field
The present invention relates to a kind of power-supply system, relate in particular to a kind of power-supply system that is applied to lcd tv display.
Background technology
Usually, the power-supply system of LCD TV comprises two parts, and a part is the backlight power supply of LCD TV, and another part then is the control system power supply of LCD TV.Figure 1 shows that the circuit theory diagrams of the known power-supply system that is applied to LCD TV 10.Power-supply system 10 is used to drive a plurality of fluorescent tubes 110, and be control system 114 power supply, it comprises rectification circuit 102, circuit of power factor correction 104, DC/DC conversion circuit (1) 106, secondary DC/DC conversion circuit (2) 112 and a converter circuit 108.AC power AC is converted to direct voltage DC and is transferred to circuit of power factor correction 104 after rectification circuit 102 is handled, DC/DC conversion circuit (1) 106 is converted to converter circuit 108 required galvanic currents with the direct voltage of circuit of power factor correction 104 outputs and presses and have concurrently the effect that safety is isolated, and converter circuit 108 is converted to alternating voltage to drive light tube group 110 by AC/DC converter with the direct voltage that receives.Secondary DC/DC conversion circuit (2) 112 is converted to the required low-voltage DC of control system 114 with the direct voltage of circuit of power factor correction 104 output, and has the effect that safety is isolated concurrently.As can be seen from Figure 1, AC power outputs to fluorescent tube from rectification circuit, and energy changes through three times, causes the power loss of whole power-supply system 10 big, and efficient is low.
Summary of the invention
In view of this, need provide a kind of power-supply system that is applied to LCD TV, can reduce the number of times of power conversion, effectively reduce the power loss in the power source conversion process.
A kind of power-supply system that is applied to LCD TV comprises rectification circuit, lamp tube drive circuit and control system power circuit.Described rectification circuit is connected in external ac power source, and the external electric signal that is used for described AC power is provided is converted to first electric signal.Described lamp tube drive circuit comprises single-stage power factor correcting circuit, converter circuit and current balance circuit.Wherein, described single-stage power factor correcting circuit is connected in described rectification circuit, is used for described first electric signal is formed second electric signal after power factor correction and DC/DC conversion, and has the function that safety is isolated concurrently.Described converter circuit is connected in described single-stage power factor correcting circuit, is used for described second electric signal is converted to driving described alternating current voltage signal.Described current balance circuit is used for the electric current between each fluorescent tube of balance.
Power-supply system provided by the invention, its lamp tube drive circuit is with circuit of power factor correction and DC/DC conversion is circuit integrated is integral, reduced the number of times of power conversion, effectively reduce the power loss in the power source conversion process, reduced the usage quantity of circuit board feature simultaneously, effectively reduced the cost.
Description of drawings
Fig. 1 is the circuit theory diagrams of known liquid crystal display television (LCD TV) power system.
Fig. 2 is the circuit theory diagrams of liquid crystal display television (LCD TV) power system of the present invention.
Fig. 3 is the rectification circuit of liquid crystal display television (LCD TV) power system among Fig. 2 and the physical circuit figure of lamp tube drive circuit one embodiment.
Fig. 4 is the rectification circuit of liquid crystal display television (LCD TV) power system among Fig. 2 and the physical circuit figure of another embodiment of lamp tube drive circuit.
Embodiment
Shown in Figure 2 is the circuit theory diagrams that are applied to the power-supply system 20 of LCD TV in the embodiment of the invention.Power-supply system 20 is used to drive a plurality of fluorescent tubes 208, is control system 210 power supplies of LCD TV simultaneously, and it comprises rectification circuit 202, lamp tube drive circuit 204 and control system power circuit 206.Wherein, lamp tube drive circuit 204 comprises single-stage power factor correcting circuit 2042, converter circuit 2044 and current balance circuit 2046.AC power AC is converted to the first electric signal V1 and is sent to single-stage power factor correcting circuit 2042 through behind the rectification circuit 202.Single-stage power factor correcting circuit 2042 is connected between rectification circuit 202 and the converter circuit 2044, and the first electric signal V1 that is used for receiving is converted to the second electric signal V2 and has the function that safety is isolated concurrently.Converter circuit 2044 is connected in single-stage power factor correcting circuit 2042, and the second electric signal V2 that is used for receiving is converted to the alternating voltage signal that can drive light tube group 208.Current balance circuit 2046 is used for the electric current between each fluorescent tube of balance.
In the present embodiment, single-stage power factor correcting circuit 2042 has been integrated the function of circuit of power factor correction and DC/DC conversion circuit, make AC power output to 208 of fluorescent tubes of driving and passed through twice conversion from rectification circuit 202, improved power supply conversion efficiency, reduced power loss, reduce number of spare parts simultaneously, saved cost.
Control system power circuit 206 comprises circuit of power factor correction 2062 and secondary DC/DC conversion circuit (2) 2064.Circuit of power factor correction 2062 is connected in rectification circuit 202, is used for the first electric signal V1 power factor correcting with rectification circuit 202 outputs.Secondary DC/DC conversion circuit (2) 2064 is connected between circuit of power factor correction 2062 and the control system 210, be used for the direct voltage of circuit of power factor correction 2062 outputs is converted to low-voltage direct to control system 210 power supplies, simultaneously, secondary DC/DC conversion circuit (2) has the function that safety is isolated concurrently.
Figure 3 shows that the physical circuit figure of rectification circuit 202 and lamp tube drive circuit 204 among Fig. 2.In this example, rectification circuit 202 comprises the rectifier S and first capacitor C 1, and the input of rectifier S is connected in AC power AC, the output that first capacitor C 1 is connected in rectifier S in and ground between.The conversion first electric signal V1 behind the AC power AC process rectifier S, first capacitor C 1 is used for the described first electric signal V1 is carried out filtering.In the present embodiment, the capacitance of first capacitor C 1 is smaller, make the first electric signal V1 that tangible input voltage harmonic wave can be arranged, and so just can obtain the waveform shape of input voltage, to reach higher power factor correction.
Single-stage power factor correcting circuit 2042 comprises field-effect transistor F, isolating transformer T, current rectifying and wave filtering circuit 20421 and control circuit 20422.One end of the primary side of isolating transformer T is connected in the output of rectification circuit 202, and the drain electrode of field-effect transistor F is connected in the other end of the primary side of isolating transformer, and source ground, gate are connected to control circuit 20422.The control of the controlled circuit 20422 of the gate of field-effect transistor F and change its break-make frequency.The primary side of isolating transformer T receives the described first electric signal V1, and forms the 3rd electric signal V3 at its secondary side.In the present embodiment, isolating transformer T has the function that safety is isolated concurrently.
Current rectifying and wave filtering circuit 20421 comprises the diode D and second capacitor C 2.The anode of diode D is connected in an end of isolating transformer T secondary side, and second capacitor C 2 is connected between the negative electrode and ground of diode D.The other end of isolating transformer T secondary side is ground connection also.Form the described second electric signal V2 after the 3rd electric signal V3 process diode D rectification and capacitor C 2 filtering, to be transferred to converter circuit 206.In the present embodiment, the described second electric signal V2 is a dc signal.
Control circuit 20422 is used for feedback and controls the described second electric signal V2, and it comprises feedback circuit 204221, photoelectrical coupler P, single-level power factor correction controller 204222.Feedback circuit 204221 is connected in the input of photoelectrical coupler P, is used to receive the second electric signal V2 and lamp current feedback signal, and the second electric signal V2 and lamp current feedback signal are converted to a feedback electric signal, is used to drive photoelectrical coupler P.Photoelectrical coupler P is used for described feedback electric signal is fed back to single-level power factor correction controller 204222 with coupled modes.Single-level power factor correction controller 204222 is connected between the output and field-effect transistor F gate of photoelectrical coupler P, be used to read the feedback electric signal of photoelectrical coupler P output, and according to the break-make frequency of described feedback electric signal output controlling signal with controlling filed effect transistor F gate, thereby the output of control isolating transformer T, to adjust the second electric signal V2, reach the purpose of stablizing each lamp current.
When the second electric signal V2 was in a stationary value, single-level power factor correction controller 204222 changed the break-make frequency of field-effect transistor F gate according to input voltage and lamp current with meeting.When input voltage reduced, the highest break-make frequency of single-level power factor correction controller 204222 control field effect transistor F gates also can and then reduce; When input voltage improved, the highest break-make frequency of single-level power factor correction controller 204222 control field effect transistor F gates also can and then improve, and makes the second electric signal V2 fall back to described stationary value.
When each lamp tube current increased in the light tube group 208 of flowing through, the highest break-make frequency of control field effect transistor F gate also can and then reduce.When each lamp tube current reduced in the light tube group 208 of flowing through, the highest break-make frequency of control field effect transistor F gate also can and then improve, and makes the second electric signal V2 be in stable state, thus equiulbrium flow each lamp tube current in light tube group 208.
The power-supply system 20 that is applied to LCD TV provided by the invention, the lamp current signal can pour into the back coupling of single-stage power factor correcting circuit 2042, by adjusting the height of the second electric signal V2 voltage, reaches the control of lamp current loop circuit.
Figure 4 shows that the physical circuit figure of rectification circuit 202 and lamp tube drive circuit 204 ' in another execution mode of the present invention.Lamp tube drive circuit 204 ' and lamp tube drive circuit 204 shown in Figure 3 have the circuit framework of basically identical, and its difference is that the current balance circuit 2046 ' of lamp tube drive circuit 204 ' is made up of filter circuit 30 and flow equalizing circuit 40.Wherein, filter circuit 30 is connected between AC 20441 and the flow equalizing circuit 40, comprises transformer T2 and capacitor C 3, is used for square-wave signal is converted to the string ripple signal that drives fluorescent tube, flow equalizing circuit 40 is connected in light tube group 208, is used for the electric current between each fluorescent tube of balance.
The power-supply system that is applied to LCD TV provided by the invention, with circuit of power factor correction and DC/DC conversion is circuit integrated is integral, reduced the number of times of power conversion, effectively reduce the power loss in the power source conversion process, reduce the quantity of circuit board feature simultaneously, effectively lowered cost.
Claims (6)
1. power-supply system that is applied to LCD TV comprises:
Rectification circuit is connected with external ac power source, and the external electric signal that is used for described AC power is provided is converted to first electric signal;
Lamp tube drive circuit is connected in described rectification circuit, is used to drive a plurality of fluorescent tubes;
The control system power circuit is connected in described rectification circuit, is used to the control system of described LCD TV that power supply is provided;
It is characterized in that described lamp tube drive circuit comprises:
Single-stage power factor correcting circuit is connected in described rectification circuit, is used for described first electric signal is formed second electric signal after power factor correction and DC/DC conversion;
Converter circuit links to each other with described single-stage power factor correcting circuit, is used for described second electric signal is converted to driving described alternating current voltage signal;
Current balance circuit is used for the electric current between the described fluorescent tube of balance.
2. power-supply system as claimed in claim 1 is characterized in that, described single-stage power factor correcting circuit comprises:
Isolating transformer, its primary side first end is connected in the output of described rectification circuit, is used to receive described first electric signal, and forms the 3rd electric signal at its secondary side, and first electric signal and the 3rd electric signal are isolated;
Current rectifying and wave filtering circuit is connected in the secondary side of described isolating transformer, is used for described the 3rd electric signal is converted to described second electric signal;
Control circuit is connected in described filter circuit, thereby is used for adjusting described second electric signal according to the output that described second electric signal provides controlling signal to control described isolating transformer.
3. power-supply system as claimed in claim 2, it is characterized in that, described single-stage power factor correcting circuit further comprises field-effect transistor, its drain electrode is connected in the primary side low-pressure end of described isolating transformer, source ground, gate receives the controlling signal of described control circuit output, thereby adjusts its output with this input of controlling described isolating transformer.
4. power-supply system as claimed in claim 3, it is characterized in that, described current rectifying and wave filtering circuit comprises the diode and second electric capacity, the anode of described diode is connected in an end of described isolating transformer secondary side, described second electric capacity is connected between the negative electrode and ground of described diode, forms described second electric signal behind described the 3rd electric signal described diode rectification of process and described second capacitor filtering.
5. as claim 3 a described power-supply system, it is characterized in that described control circuit comprises:
Feedback circuit is connected in the negative electrode of described diode, is used for described second electric signal and described lamp tube current feedback signal are converted to the feedback electric signal;
Photoelectrical coupler is connected in described feedback circuit;
The single-level power factor controller is connected between the gate of the output of described photoelectrical coupler and described field-effect transistor;
Described photoelectrical coupler feeds back to described single-level power factor correction controller with described feedback electric signal in the mode that is coupled, described single-level power factor correction controller is exported the break-make frequency of described controlling signal with the gate of controlling described field-effect transistor according to described feedback electric signal, thereby controls the input of described isolating transformer and then adjust described second electric signal.
6. power-supply system as claimed in claim 1 is characterized in that, described second electric signal is a dc signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910105488A CN101814843A (en) | 2009-02-20 | 2009-02-20 | Power supply system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910105488A CN101814843A (en) | 2009-02-20 | 2009-02-20 | Power supply system |
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| Publication Number | Publication Date |
|---|---|
| CN101814843A true CN101814843A (en) | 2010-08-25 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200910105488A Pending CN101814843A (en) | 2009-02-20 | 2009-02-20 | Power supply system |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102695324A (en) * | 2011-03-25 | 2012-09-26 | 国琏电子（上海）有限公司 | Light source module power supply system |
| CN103856081A (en) * | 2012-12-06 | 2014-06-11 | 东林科技股份有限公司 | Alternating current/direct current conversion device and power factor correction method thereof |
| WO2014089877A1 (en) * | 2012-12-14 | 2014-06-19 | 深圳市华星光电技术有限公司 | Direct-lit led backlight source and liquid crystal display device thereof |
| CN103974497A (en) * | 2013-02-05 | 2014-08-06 | 国钰电子(北海)有限公司 | Light emitting diode driving system |
| CN104682720A (en) * | 2013-11-29 | 2015-06-03 | 东林科技股份有限公司 | Alternating current-alternating current power supply conversion device and conversion method thereof |
-
2009
- 2009-02-20 CN CN200910105488A patent/CN101814843A/en active Pending
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102695324A (en) * | 2011-03-25 | 2012-09-26 | 国琏电子（上海）有限公司 | Light source module power supply system |
| CN103856081A (en) * | 2012-12-06 | 2014-06-11 | 东林科技股份有限公司 | Alternating current/direct current conversion device and power factor correction method thereof |
| WO2014089877A1 (en) * | 2012-12-14 | 2014-06-19 | 深圳市华星光电技术有限公司 | Direct-lit led backlight source and liquid crystal display device thereof |
| CN103974497A (en) * | 2013-02-05 | 2014-08-06 | 国钰电子(北海)有限公司 | Light emitting diode driving system |
| CN104682720A (en) * | 2013-11-29 | 2015-06-03 | 东林科技股份有限公司 | Alternating current-alternating current power supply conversion device and conversion method thereof |
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Application publication date: 20100825 |