CN101742188B - LCD (Liquid Crystal Display)-TV power supply voltage detection circuit - Google Patents
LCD (Liquid Crystal Display)-TV power supply voltage detection circuit Download PDFInfo
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- CN101742188B CN101742188B CN 200910239630 CN200910239630A CN101742188B CN 101742188 B CN101742188 B CN 101742188B CN 200910239630 CN200910239630 CN 200910239630 CN 200910239630 A CN200910239630 A CN 200910239630A CN 101742188 B CN101742188 B CN 101742188B
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Abstract
The invention is applicable to the electronic field and provides an LCD-TV power supply voltage detection circuit, comprising a voltage-regulation control circuit and a switch control circuit connected with the voltage-regulation control circuit, wherein the voltage-regulation control circuit is also connected with an alternating voltage detection circuit so as to detect an alternating current input voltage, and the alternating voltage detection circuit comprises a first rectifier tube, serially connected pull-up resistors, namely a first resistor R1, a second resistor R2 and a third resistor R3 and a pull-down resistor, namely a fourth resistor R4, an accurate potential regulator U 1 connected to a node between the third resistor R3 and the fourth resistor R4, a first voltage-regulator tube V1 connected with the accurate potential regulator U 1 and a first audion Q1 connected with the first voltage-regulator tube V1. The alternating input voltage is detected by the alternating voltage detection circuit, and power supplied by a main circuit and a PFC circuit of a power supply is cut off when the voltage is lower than the minimum alternating voltage for the reliable working of the power supply, thereby achieving the purposes of stopping the power supply from working and protecting the power circuits.
Description
Technical field
The invention belongs to technical field of television sets, relate in particular to a kind of LCD-TV voltage detection circuit.
Background technology
At present, LCD-TV (LCD TV) is by feat of numerous advantages such as large-screen, low thickness and high definitions, and the permeability fast lifting on market, LCD TV more and more are subject to numerous consumers' welcome, and occupation rate of market constantly raises.Yet in LCD TV market development growth, its power supply is also attracted attention more.Because supply of electric power is very large in a lot of regional disparities, some area power grid electricity shortage, power supply department has to take the step-down power supply, some remote area, loss is too much, causes alternating voltage on the low side, can cause the load cisco unity malfunction.The most power supply product has all designed power factor corrector in circuit, can work relatively reliably between AC-input voltage 110～240Vac by its boost function lcd power source product, if but electrical network will cause the load cisco unity malfunction lower than exchanging 110Vac voltage.In the situation that the permanent load cisco unity malfunction can cause power supply reliability to descend, power source life shortens.
Summary of the invention
The purpose of the embodiment of the present invention is to provide a kind of LCD-TV voltage detection circuit; detect AC-input voltage; power supply at voltage power cutoff main circuit and pfc circuit during lower than the minimum alternating voltage of power supply reliably working quits work power supply, with the protection power source circuit.
the embodiment of the present invention is to realize like this, a kind of LCD-TV voltage detection circuit, comprise controlling circuit of voltage regulation, the ON-OFF control circuit that connects controlling circuit of voltage regulation, wherein, controlling circuit of voltage regulation also is connected with ac voltage detection circuit to detect AC-input voltage, this ac voltage detection circuit comprises the first rectifying tube, the pull-up resistor first that is connected in series, second, the 3rd resistance R 1, R2, R3 and pull down resistor the 4th resistance R 4, be connected to the 3rd, the 4th resistance R 3, the accurate potential regulator U1 of node between R4, the the first voltage-stabiliser tube V1 that is connected with accurate potential regulator U1, and the first triode Q1 that is connected with the first voltage-stabiliser tube V1.
In embodiments of the present invention; detect AC-input voltage by ac voltage detection circuit; power supply at voltage power cutoff main circuit and pfc circuit during lower than the minimum alternating voltage of power supply reliably working makes the out-of-work purpose of power supply, protection power source circuit thereby reach.
Description of drawings
Fig. 1 is LCD-TV voltage detection circuit theory diagram of the present invention.
Fig. 2 is the circuit theory diagrams of LCD-TV voltage detection circuit of the present invention.
Embodiment
In order to make purpose of the present invention, technical scheme and advantage clearer, below in conjunction with drawings and Examples, the present invention is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the present invention, is not intended to limit the present invention.
Fig. 1 shows LCD-TV voltage detection circuit theory diagram of the present invention, comprises the ON-OFF control circuit of controlling circuit of voltage regulation, connection controlling circuit of voltage regulation.Wherein, controlling circuit of voltage regulation also is connected with ac voltage detection circuit to detect AC-input voltage; in the situation that the electrical network input ac voltage detected lower than reliable voltage; make controlling circuit of voltage regulation there is no Voltage-output to main circuit and pfc circuit; chip is not worked; thereby power supply quits work, and plays the effect of protection power source.
Fig. 2 shows the circuit theory diagrams of LCD-TV voltage detection circuit of the present invention, wherein, ac voltage detection circuit comprises the first rectifying tube, the pull-up resistor first that is connected in series, second, the 3rd resistance R 1, R2, R3 and pull down resistor the 4th resistance R 4, with this be connected in series first, second, the 3rd, the 4th resistance R 1, R2, R3, R4 is parallel to the first capacitor C 1 together, be connected to the 3rd, the 4th resistance R 3, the accurate potential regulator U1 of node between R4, the the first voltage-stabiliser tube V1 that is connected with accurate potential regulator U1 and the second rectifying tube D2, and with the first voltage-stabiliser tube V1, the first triode Q1 that the second rectifying tube D2 connects.The R pin of U1 connects the 3rd resistance R 3 one ends, and the other end of the 3rd resistance R 3 is connected with first and second resistance R 1, R2, first resistance R 1 other end is connected with the first rectifying tube D1 one end (negative sense), first another termination of rectifying tube D1 (forward) AC singal, while first capacitor C 1 one termination the first rectifying tube D1 one ends (negative sense), other end ground connection; Accurately the R pin of potential regulator U1 also connects the 4th resistance R 4 one ends, the 4th resistance R 4 another terminations thermally, accurately the R pin of potential regulator U1 also connects the 6th resistance R 6 one ends, the 6th resistance R 6 another termination second rectifying tube D2 one ends (negative sense) in addition.The A pin ground connection of accurate potential regulator U1, and accurately the K pin of potential regulator U1 connects respectively the 5th resistance R 5 one ends and the first voltage-stabiliser tube V1 one end (negative sense), the 5th resistance R 5 other ends are connected to controlling circuit of voltage regulation, and the first voltage-stabiliser tube V1 one end (forward) connects current-limiting resistance the 7th resistance R 7 one ends; The second rectifying tube D2 one end (forward) connects the collector electrode of the first triode Q1, the collector electrode of the first triode Q1 also is connected to controlling circuit of voltage regulation, the base stage of other the first triode Q1 connects respectively the 7th resistance R 7 other ends and biasing resistor the 8th resistance R 8 one ends, the 8th resistance R 8 other end ground connection; Further the first triode Q1 grounded emitter.
Controlling circuit of voltage regulation includes the second triode Q2, connects the second capacitor C 2, the second voltage-stabiliser tube V2 and the 9th resistance R 9 of the second triode Q2 base stage.Wherein, the emitter of the second triode Q2 is connected to the 5th resistance R 5 that Vcc out, collector electrode are connected to ac voltage detection circuit, in addition, the collector electrode of the second triode Q2 also is connected with Vcc in, and base stage also connects the collector electrode of ac voltage detection circuit the first triode Q1.The 9th resistance R9 is connected to ON-OFF control circuit, and the 9th resistance R 9 also connects ground, the second capacitor C 2, the second voltage-stabiliser tube V2 one end ground connection by the tenth resistance R 10 simultaneously.ON-OFF control circuit includes photoelectrical coupler U2, the 3rd triode Q3 that is connected with photoelectrical coupler U2 that connects controlling circuit of voltage regulation and biasing resistor the 11 resistance R 11 and the filter capacitor C3 that is connected in the 3rd triode Q3 base stage.Wherein, the collector electrode of the 3rd triode Q3 connects photoelectrical coupler U2, grounded emitter.In addition, the base stage of the 3rd triode Q3 also connects the ON/OF end by current-limiting resistance the 12 resistance R 12, the 3rd rectifying tube D3.
after ON/OF start control signal process current-limiting resistance the 12 resistance R 12, under biasing resistor the 11 resistance R 11 and filter capacitor C3 acting in conjunction, the full Q3 of the 3rd triode and conducting, its current collection is low level very, the Light-Emitting Diode of photoelectrical coupler U2 is luminous, the phototriode conducting, Vcc in provides bias voltage by the 9th resistance R 9 and the rear second triode Q2 that gives of the tenth resistance R 10, the second triode Q2 saturation conduction, emitter has supply power voltage output, simultaneously, because the second triode Q2 base stage is connected to the second voltage-stabiliser tube V2, the emitter output voltage clamper of the second triode Q2 is under the voltage of voltage regulation of the second voltage-stabiliser tube V2.
in the situation that mains supply voltage conforms LCD-TV power work condition (being not less than 110Vac), AC-input voltage through bridge rectifier and after sample resistance sampling voltage more than or equal to 2.5Vdc, this voltage makes accurate potential regulator U1 conducting, this moment, accurately the K point voltage of potential regulator U1 was low level, the first voltage-stabiliser tube V1 can not be punctured by neat sodium, do not have electric current to flow through the first voltage-stabiliser tube V1, thereby the first triode Q1 cut-off, the base stage of the second triode Q2 in controlling circuit of voltage regulation is high level, controlling circuit of voltage regulation is normal, supply power voltage output is arranged, power work is normal.and when AC-input voltage during lower than 110Vac (parameters is as a reference point with 110Vac), AC-input voltage is through after bridge rectifier, again through the first rectifying tube D1 rectification and pull-up resistor first, second, the 3rd resistance R 1, R2, R3, after taking a sample with pull down resistor the 4th resistance R 4, the sampling point voltages are less than 2.5Vdc, LM431 turn-offs under this voltage, this moment, Vcc in punctured the first neat sodium of voltage-stabiliser tube V1 after through the 5th resistance R 5 dividing potential drops, electric current flows through the first voltage-stabiliser tube V1, make the first triode Q1 saturation conduction under the acting in conjunction of current-limiting resistance the 7th resistance R 7 and biasing resistor the 8th resistance R 8, this moment the first triode Q1 current collection low level very, the base potential of the second triode Q2 in controlling circuit of voltage regulation is dragged down, cause controlling circuit of voltage regulation work undesired, export without VCC out.Power supply chip is not worked, and causes power supply to quit work, and is in guard mode.In addition, the 6th resistance R 6 and the second rectifying tube D2 form compensating circuit, to prevent causing power supply possibly can't work at set point (110Vac) because of the problem of parameter error.
The above is only preferred embodiment of the present invention, not in order to limiting the present invention, all any modifications of doing within the spirit and principles in the present invention, is equal to and replaces and improvement etc., within all should being included in protection scope of the present invention.
Claims (1)
1. LCD-TV voltage detection circuit, comprise controlling circuit of voltage regulation, the ON-OFF control circuit that connects controlling circuit of voltage regulation, it is characterized in that: controlling circuit of voltage regulation also is connected with ac voltage detection circuit to detect AC-input voltage, this ac voltage detection circuit comprises the first rectifying tube (D1), the pull-up resistor first that is connected in series, second, the 3rd resistance (R1), (R2), (R3) and pull down resistor the 4th resistance (R4), be connected to the 3rd, the 4th resistance (R3), (R4) the accurate potential regulator (U1) of node between, the first voltage-stabiliser tube (V1) that is connected with accurate potential regulator (U1), and the first triode (Q1) that is connected with the first voltage-stabiliser tube (V1),
Described ac voltage detection circuit also includes by the 6th resistance (R6) and the second rectifying tube (D2) and forms compensating circuit, and wherein the 6th resistance (R6) end connects accurate potential regulator (U1), another termination second rectifying tube (D2);
Be connected in parallel to the first electric capacity (C1) with described first, second, third, fourth resistance (R1), (R2), (R3), (R4) that is connected in series;
The collector electrode of described the first triode (Q1) is connected to controlling circuit of voltage regulation, and base stage is connected to respectively current-limiting resistance the 7th resistance (R7) and biasing resistor the 8th resistance (R8), the 8th resistance (R8) other end and the first triode (Q1) emitter common ground;
Described controlling circuit of voltage regulation includes the second triode (Q2), connects the second electric capacity (C2), the second voltage-stabiliser tube (V2) and the 9th resistance (R9) of the second triode (Q2) base stage;
The emitter of the second triode (Q2) is connected to Vcc out, collector electrode and also connects Vcc in, and base stage connects the collector electrode of ac voltage detection circuit the first triode (Q1);
Described ON-OFF control circuit includes photoelectrical coupler (U2), the 3rd triode (Q3) that is connected with photoelectrical coupler (U2) that connects controlling circuit of voltage regulation and biasing resistor the 11 resistance (R11) and the filter capacitor (C3) that is connected in the 3rd triode (Q3) base stage;
The collector electrode of described the 3rd triode (Q3) connects photoelectrical coupler (U2), grounded emitter, and in addition, the base stage of the 3rd triode (Q3) also connects the ON/OF end by current-limiting resistance the 12 resistance (R12), the 3rd rectifying tube (D3).
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| CN 200910239630 CN101742188B (en) | 2009-12-31 | 2009-12-31 | LCD (Liquid Crystal Display)-TV power supply voltage detection circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 200910239630 CN101742188B (en) | 2009-12-31 | 2009-12-31 | LCD (Liquid Crystal Display)-TV power supply voltage detection circuit |
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| CN101742188A CN101742188A (en) | 2010-06-16 |
| CN101742188B true CN101742188B (en) | 2013-06-12 |
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Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102998516B (en) * | 2012-11-21 | 2015-02-25 | 上海富欣智能交通控制有限公司 | Detection circuit for voltage state of output channel |
| CN105450054B (en) * | 2014-06-26 | 2018-11-27 | 欧普照明股份有限公司 | Circuit of power factor correction carries auxiliary power circuit and its control method and device |
| CN104378811A (en) * | 2014-11-14 | 2015-02-25 | 惠州Tcl移动通信有限公司 | Mobile terminal LCD luminance detection and control method and system |
| CN105137871B (en) * | 2015-08-18 | 2018-10-19 | 广州能迪能源科技股份有限公司 | A kind of universal expansion module applied to network monitoring system for things |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201017134Y (en) * | 2007-03-12 | 2008-02-06 | 深圳创维－Rgb电子有限公司 | Testing circuit of LCD electric power |
| CN201266984Y (en) * | 2008-10-13 | 2009-07-01 | 深圳创维－Rgb电子有限公司 | Detection circuit for LCD-TV power supply |
| CN201307826Y (en) * | 2008-10-13 | 2009-09-09 | 深圳创维－Rgb电子有限公司 | LCD-TV power supply voltage detecting circuit |
| CN201349177Y (en) * | 2009-01-19 | 2009-11-18 | 深圳市中联数源电子有限公司 | LCD regulated power supply circuit |
-
2009
- 2009-12-31 CN CN 200910239630 patent/CN101742188B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN201017134Y (en) * | 2007-03-12 | 2008-02-06 | 深圳创维－Rgb电子有限公司 | Testing circuit of LCD electric power |
| CN201266984Y (en) * | 2008-10-13 | 2009-07-01 | 深圳创维－Rgb电子有限公司 | Detection circuit for LCD-TV power supply |
| CN201307826Y (en) * | 2008-10-13 | 2009-09-09 | 深圳创维－Rgb电子有限公司 | LCD-TV power supply voltage detecting circuit |
| CN201349177Y (en) * | 2009-01-19 | 2009-11-18 | 深圳市中联数源电子有限公司 | LCD regulated power supply circuit |
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| CN101742188A (en) | 2010-06-16 |
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Effective date of registration: 20151217 Address after: 336000 No. 108, Chun route, Yichun economic and Technological Development Zone, Jiangxi Patentee after: SKYWORTH ELECTRONIC DEVICE (YICHUN) Co.,Ltd. Address before: 518057 Guangdong city of Shenzhen province Nanshan District Gao Xin Road SKYWORTH building A13-16 Patentee before: SHENZHEN SKYWORTH-RGB ELECTRONIC Co.,Ltd. |
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Effective date of registration: 20221208 Address after: 336000 No. 2 chunhang Road, Yichun economic and Technological Development Zone, Jiangxi Province Patentee after: SKYWORTH core electronics (Yichun) Co.,Ltd. Address before: No. 108, Chunhang Road, Yichun Economic and Technological Development Zone, Jiangxi Province, 336000 Patentee before: SKYWORTH ELECTRONIC DEVICE (YICHUN) Co.,Ltd. |
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