CN100437242C - Power supply and discharge circuit of liquid-crystal display - Google Patents
Power supply and discharge circuit of liquid-crystal display Download PDFInfo
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- CN100437242C CN100437242C CNB2006100615590A CN200610061559A CN100437242C CN 100437242 C CN100437242 C CN 100437242C CN B2006100615590 A CNB2006100615590 A CN B2006100615590A CN 200610061559 A CN200610061559 A CN 200610061559A CN 100437242 C CN100437242 C CN 100437242C
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- lcd device
- device electric
- power supply
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Abstract
The invention discloses a LCD power supply and discharge circuit, comprising: a power supply, a control signal input end, a power supply and discharge end, a discharge resistor, an NPN bipolar transistor and P-channel enhanced MOSFET, where the NPN bipolar transistor's base is connected to the control signal input end, the emitter of the NPN bipolar transistor is earthed, and the collector of the NPN bipolar transistor is connected via a bias resistor to the power supply; the P-channel enhanced MOSFET's grid is connected to the collector of the NPN bipolar transistor, the source of the P-channel enhanced MOSFET is connected to the power supply and the drain of the P-channel enhanced MOSFET is connected to the power supply and discharge end; the power supply and discharge end is earthed via the discharge resistor.
Description
Technical field
The present invention relates to a kind of LCD device electric supply and discharge circuit.
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.Usually, comprise in the LCD that feed circuit power to it.In addition, because the LCD internal circuit is a capacitive load, make LCD after outage, a large amount of residual charges be arranged still, so LCD also need a discharge circuit to discharge described residual charge.
Seeing also Fig. 1, is the synoptic diagram of a kind of prior art LCD device electric supply and discharge circuit.This LCD device electric supply and discharge circuit 10 comprise a signal input end 110, one for discharge end 120, the ambipolar the first transistor 150 of one 12V direct supply, 130, one 5V direct supplys, 140, one NPN, the ambipolar transistor seconds 170 of one NPN, one N channel enhancement MOS field-effect transistor, 160, one first resistance, 155, one second resistance 156, one the 3rd resistance 165, one the 4th resistance 175 and one the 5th resistance 176.
The base stage b of this first transistor 150 is connected to this signal input end 110 via this first resistance 155, emitter-base bandgap grading e is connected to this base stage b via this second resistance 156, and this emitter-base bandgap grading e ground connection, collector c is connected to this 12V direct supply 130 via the 3rd resistance 165.
The base stage b of this transistor seconds 170 is connected to this signal input end 110 via the 4th resistance 175, emitter-base bandgap grading e ground connection, and collector c is connected to this confession discharge end 120 via the 5th resistance 176.
The grid G of this N channel enhancement MOS field-effect transistor 160 is connected to the collector c of the ambipolar the first transistor 150 of this NPN, and source S is connected to this confession discharge end 120, and drain D is connected to this 5V direct supply 140.
The principle of work of this LCD device electric supply and discharge circuit 10 is as follows:
When this signal input end 110 is a logic low, this the first transistor 150 and this transistor seconds 170 all end, this 12V direct supply 130 is applied to the grid G of this N channel enhancement MOS field-effect transistor 160 via the 3rd resistance 165, makes 160 conductings of this N channel enhancement MOS field-effect transistor.This 5V direct supply 140 is applied to this confession discharge end 120 via the N channel enhancement MOS field-effect transistor 160 that is in conducting state, to LCD device electric supply.
When this signal input end 110 is a logic high, these first, second transistor 150,170 equal conductings, the grid G of this N channel enhancement MOS field-effect transistor 160 is via these the first transistor 150 ground connection that are in conducting state, and drop-down is low level.Therefore this N channel enhancement MOS field-effect transistor 160 ends.This moment, this confession discharge end 120 discharged the residual charge of this LCD inside successively via the 5th resistance 176 and these transistor seconds 170 ground connection that are in conducting state.
Because this LCD device electric supply and discharge circuit 10 comprise two direct supplys 130,140, make the wiring of this LCD device electric supply and discharge circuit 10 comparatively complicated.
Summary of the invention
The complicated shortcoming of wiring in order to solve LCD device electric supply and discharge circuit in the prior art is necessary to provide better simply LCD device electric supply of a kind of wiring and discharge circuit.
A kind of LCD device electric supply and discharge circuit, it comprises a power supply, and one provides the signal input end of control signal, and one is used to the discharge end that supplies of this LCD device electric supply and discharge, one discharge resistance, a npn bipolar transistor and a P-channel enhancement type MOS field-effect transistor.The base stage of this npn bipolar transistor is connected to this signal input end, emitter grounding, and collector is connected to this power supply via a biasing resistor.The grid of this P-channel enhancement type MOS field-effect transistor is connected to the collector of this npn bipolar transistor, and source electrode is connected to this power supply, and drain electrode is connected to this confession discharge end.This supplies discharge end via this discharge resistance ground connection.
A kind of LCD device electric supply and discharge circuit, it comprises a power supply, one provides the signal input end of control signal, one is used to the discharge end that supplies of this LCD device electric supply and discharge, one discharge resistance, a N channel enhancement MOS field-effect transistor and a P-channel enhancement type MOS field-effect transistor.The grid of this N channel enhancement MOS field-effect transistor is connected to this signal input end, source ground, and drain electrode is connected to this power supply via a biasing resistor.The grid of this P-channel enhancement type MOS field-effect transistor be connected to this N channel enhancement MOS field-effect transistor drain electrode, source electrode is connected to this power supply, drain electrode is connected to this confession discharge end.This supplies discharge end via this discharge resistance ground connection.
A kind of LCD device electric supply and discharge circuit, it comprises a power supply, and one provides the signal input end of control signal, and one is used to confession discharge end, a discharge resistance, a npn bipolar transistor and a PNP bipolar transistor of this LCD device electric supply and discharge.The base stage of this npn bipolar transistor is connected to this signal input end, emitter grounding, and collector is connected to this power supply via a biasing resistor.The base stage of this PNP bipolar transistor is connected to the collector of this npn bipolar transistor, and the collector of this PNP bipolar transistor is connected to this power supply, and the emitter-base bandgap grading of this PNP bipolar transistor is connected to this confession discharge end.This supplies discharge end via this discharge resistance ground connection.
Compared to prior art, above-mentioned LCD device electric supply and discharge circuit only comprise a power supply, and number of transistors is less and also do not increase other assembly, so the wiring of this LCD device electric supply and discharge circuit is comparatively simple.
Description of drawings
Fig. 1 is the circuit diagram of a kind of prior art LCD device electric supply and discharge circuit.
Fig. 2 is the synoptic diagram of LCD device electric supply of the present invention and discharge circuit first embodiment.
Fig. 3 is the synoptic diagram of LCD device electric supply of the present invention and discharge circuit second embodiment.
Embodiment
Seeing also Fig. 2, is the synoptic diagram of LCD device electric supply of the present invention and discharge circuit first embodiment.This LCD device electric supply and discharge circuit 20 comprise that a signal input end 210, is for discharge end 220, one 5V direct supplys 230, one npn bipolar transistor, 240, one P-channel enhancement type MOS field-effect transistors, 250, one current-limiting resistances 245, one biasing resistor 255 and a discharge resistance 266.This signal input end 210 provides a control signal, and this control signal is a logic high or a logic low.This confession discharge end 220 is LCD device electric supply and discharge according to this control signal.
The base stage b of this npn bipolar transistor 240 is connected to this signal input end 210 via this current-limiting resistance 245, emitter-base bandgap grading e ground connection, and collector c is connected to this 5V direct supply 230 via this biasing resistor 255.
The grid G of this P-channel enhancement type MOS field-effect transistor 250 is connected to the collector c of this npn bipolar transistor 240, and source S is connected to this 5V direct supply 230, and drain D is connected to this confession discharge end 220.
This supplies discharge end 220 via these discharge resistance 266 ground connection.
The principle of work of this LCD device electric supply and discharge circuit 20 is as follows:
When this signal input end 210 is a logic high, these npn bipolar transistor 240 conductings, the grid G of this P-channel enhancement type MOS field-effect transistor 250 is via these npn bipolar transistor 240 ground connection that are in conducting state, and the source S of this P-channel enhancement type MOS field-effect transistor 250 is connected to this 5V direct supply 230, thus the grid G of this P-channel enhancement type MOS field-effect transistor 250 and source S between voltage V
GS=-5V makes 250 conductings of this P-channel enhancement type MOS field-effect transistor.This 5V direct supply 230 provides to this confession discharge end 220 via this P-channel enhancement type MOS field-effect transistor 250 that is in conducting state, thereby to this LCD device electric supply.
When this signal input end 210 was a logic low, this npn bipolar transistor 240 ended, the voltage V between the grid G of this P-channel enhancement type MOS field-effect transistor 250 and source S
GS=0V, so this P-channel enhancement type MOS field-effect transistor 250 ends.This moment, this confession discharge end 220 discharged the residual charge of this LCD via these discharge resistance 266 ground connection.
Because this LCD device electric supply and discharge circuit 20 only comprise a power supply 230 compared to prior art, number of transistors is less and also do not increase other assembly, so the wiring of this LCD device electric supply and discharge circuit 20 is comparatively simple.
Seeing also Fig. 3, is the synoptic diagram of LCD device electric supply of the present invention and discharge circuit second embodiment.This LCD device electric supply and discharge circuit 30 are with the difference of this LCD device electric supply and discharge circuit 20: this LCD device electric supply and discharge circuit 30 further comprise an electric capacity 346 and a charging resistor 365.One end of this electric capacity 346 is connected to the base stage b of the first transistor 340, other end ground connection.Signal input end 310 is connected to 5V direct supply 330 via this charging resistor 365.Wherein, this electric capacity 346 constitutes a RC integrating circuit with current-limiting resistance 345.The logic level that this RC integrating circuit can be avoided signal input end 310 is from low to high the time, this npn bipolar transistor 340 and the 350 unexpected conductings of this P-channel enhancement type MOS field-effect transistor, and then make this 5V direct supply 330 generation super-high-current via the time for discharge end 320 input LCD.This charging resistor 365 can be quickened the charging process of this electric capacity 346.
LCD device electric supply of the present invention and discharge circuit can also have other change design, for example: in this LCD device electric supply and discharge circuit 20, this npn bipolar transistor 240 is replaceable to be a N channel enhancement MOS field-effect transistor, its grid G is connected to this signal input end 210 via this current-limiting resistance 245, source S ground connection, drain D is connected to this 5V direct supply 230 via this biasing resistor 255.
In this LCD device electric supply and the discharge circuit 20, this P-channel enhancement type MOS field-effect transistor 250 is also replaceable to be a bipolarity PNP bipolar transistor, its base stage b is connected to the collector c of this npn bipolar transistor 240, the emitter-base bandgap grading e of this PNP bipolar transistor is connected to this 5V direct supply 230, and the collector c of this PNP bipolar transistor is connected to this confession discharge end 220.
In this LCD device electric supply and the discharge circuit 20, this npn bipolar transistor 240 and this P-channel enhancement type MOS field-effect transistor 250 also can replace with a N channel enhancement MOS field-effect transistor and a bipolarity PNP bipolar transistor respectively.It is with reference to aforementioned two change designs that its circuit connects the pass.
Claims (10)
1. LCD device electric supply and discharge circuit, it comprises:
One power supply;
One signal input end, it provides a control signal;
One for discharge end, is used to this LCD device electric supply and discharge;
One npn bipolar transistor, its base stage is connected to this signal input end, emitter grounding, collector is connected to this power supply via a biasing resistor;
One P-channel enhancement type MOS field-effect transistor, its grid is connected to the collector of this npn bipolar transistor, and source electrode is connected to this power supply, and drain electrode is connected to this confession discharge end;
With
One discharge resistance, this supplies discharge end via this discharge resistance ground connection.
2. LCD device electric supply as claimed in claim 1 and discharge circuit is characterized in that: this LCD device electric supply and discharge circuit further comprise an electric capacity, and an end of this electric capacity is connected to the base stage of this npn bipolar transistor, other end ground connection.
3. LCD device electric supply as claimed in claim 2 and discharge circuit is characterized in that: this LCD device electric supply and discharge circuit further comprise a charging resistor, and this signal input end is connected to this power supply via this charging resistor.
4. LCD device electric supply as claimed in claim 1 and discharge circuit, it is characterized in that: this LCD device electric supply and discharge circuit further comprise a current-limiting resistance, and the base stage of this npn bipolar transistor is connected to this signal input end via this current-limiting resistance.
5. LCD device electric supply as claimed in claim 1 and discharge circuit is characterized in that: this power supply is one a+5V direct supply.
6. LCD device electric supply as claimed in claim 1 and discharge circuit is characterized in that: this control signal is a high level or a low level.
7. LCD device electric supply and discharge circuit, it comprises:
One power supply;
One signal input end, it provides a control signal;
One for discharge end, is used to this LCD device electric supply and discharge;
One N channel enhancement MOS field-effect transistor, its grid is connected to this signal input end, source ground, drain electrode is connected to this power supply via a biasing resistor;
One P-channel enhancement type MOS field-effect transistor, its grid are connected to the drain electrode of this N channel enhancement MOS field-effect transistor, and source electrode is connected to this power supply, and drain electrode is connected to this confession discharge end; With
One discharge resistance, this supplies discharge end via this discharge resistance ground connection.
8. LCD device electric supply as claimed in claim 7 and discharge circuit, it is characterized in that: this LCD device electric supply and discharge circuit further comprise an electric capacity, one end of this electric capacity is connected to the grid of this N channel enhancement MOS field-effect transistor, other end ground connection.
9. LCD device electric supply and discharge circuit, it comprises:
One power supply;
One signal input end, it provides a control signal;
One for discharge end, is used to this LCD device electric supply and discharge;
One npn bipolar transistor, its base stage is connected to this signal input end, emitter grounding, collector is connected to this power supply via a biasing resistor;
One PNP bipolar transistor, its base stage is connected to the collector of this npn bipolar transistor, and the collector of this PNP bipolar transistor is connected to this power supply, and the emitter-base bandgap grading of this PNP bipolar transistor is connected to this confession discharge end; With
One discharge resistance, this supplies discharge end via this discharge resistance ground connection.
10. LCD device electric supply as claimed in claim 9 and discharge circuit is characterized in that: this LCD device electric supply and discharge circuit further comprise an electric capacity, and an end of this electric capacity is connected to the base stage of this npn bipolar transistor, other end ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100615590A CN100437242C (en) | 2006-07-07 | 2006-07-07 | Power supply and discharge circuit of liquid-crystal display |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100615590A CN100437242C (en) | 2006-07-07 | 2006-07-07 | Power supply and discharge circuit of liquid-crystal display |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101101387A CN101101387A (en) | 2008-01-09 |
| CN100437242C true CN100437242C (en) | 2008-11-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006100615590A Expired - Fee Related CN100437242C (en) | 2006-07-07 | 2006-07-07 | Power supply and discharge circuit of liquid-crystal display |
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| CN (1) | CN100437242C (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102751705A (en) * | 2009-02-10 | 2012-10-24 | 威盛电子股份有限公司 | Electronic device with overvoltage protection and overvoltage protection method thereof |
| CN105096822B (en) * | 2015-07-02 | 2018-09-04 | 深圳市华星光电技术有限公司 | A kind of 3D display system |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1495494A (en) * | 2002-08-02 | 2004-05-12 | �ձ�����Һ����ʾ������ʽ���� | Liquid crystal display |
| US7009663B2 (en) * | 2003-12-17 | 2006-03-07 | Planar Systems, Inc. | Integrated optical light sensitive active matrix liquid crystal display |
| CN1779541A (en) * | 2004-11-24 | 2006-05-31 | 三星Sdi株式会社 | Liquid crystal display (LCD) device |
-
2006
- 2006-07-07 CN CNB2006100615590A patent/CN100437242C/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1495494A (en) * | 2002-08-02 | 2004-05-12 | �ձ�����Һ����ʾ������ʽ���� | Liquid crystal display |
| US7009663B2 (en) * | 2003-12-17 | 2006-03-07 | Planar Systems, Inc. | Integrated optical light sensitive active matrix liquid crystal display |
| CN1779541A (en) * | 2004-11-24 | 2006-05-31 | 三星Sdi株式会社 | Liquid crystal display (LCD) device |
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| Publication number | Publication date |
|---|---|
| CN101101387A (en) | 2008-01-09 |
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Granted publication date: 20081126 Termination date: 20190707 |
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