CN100529858C - Electric power circuit - Google Patents
Electric power circuit Download PDFInfo
- Publication number
- CN100529858C CN100529858C CNB2006100645859A CN200610064585A CN100529858C CN 100529858 C CN100529858 C CN 100529858C CN B2006100645859 A CNB2006100645859 A CN B2006100645859A CN 200610064585 A CN200610064585 A CN 200610064585A CN 100529858 C CN100529858 C CN 100529858C
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- China
- Prior art keywords
- circuit
- display controller
- power circuit
- pulse width
- effect transistor
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Abstract
The invention relates to a power supply circuit which consists of a display controller, a pulsewidth control circuit, a soft start capacitance, and a field effect transistor. The display controller includes an output end, and the pulsewidth control circuit includes an input end. The grid of the field effect transistor is in electric connection with the output end of the display controller, the source thereof is earthed, the drain thereof is earthed through the soft start capacitance, and the input end of the pulsewidth control circuit is in electric connection with the drain of the field effect transistor. The power supply circuit has the advantages of simplified circuit structure and decreased noise interference.
Description
Technical field
The present invention relates to a kind of power circuit.
Background technology
Electronic product such as LCD, LCD TV is controlled the work of its power circuit usually with pulse width adjusting circuit.But, this power circuit can produce the phenomenon of dash current or output voltage overshoot connecting and turn-off transient, is easy to this pulse width adjusting circuit and some other electronic components are caused damage, therefore, the power circuit of liquid crystal indicator is necessary to provide soft start function.
Seeing also Fig. 1, is a kind of synoptic diagram of prior art power circuit.This power circuit 10 comprises a first input end 101, one second input end 102, a display controller (Scaler Integrated Circuit) 11, one filter capacitor 12, a SS (soft start) control circuit 13, a pulse width adjustment (Pulse Width Modulation, PWM) circuit 15, an inverter (Inverter) 17 and a soft start capacitor 19.
This display controller 11 comprises an input end 111 and an output terminal 113, and this input end 111 is electrically connected the first input end 101 of this power circuit 10, and this output terminal 113 is by these filter capacitor 12 ground connection.This display controller 11 can be integrated circuit GM5621.
This SS (soft start) control circuit 13 comprises one first bipolar transistor 131, one second bipolar transistor 133, one first biasing resistor 135, one second biasing resistor 137 and one the 3rd biasing resistor 139.These first bipolar transistor, 131 base stages are electrically connected the output terminal 113 of this display controller 11 by this first biasing resistor 135, these first bipolar transistor, 131 base stages are simultaneously by these second biasing resistor, 137 ground connection, these first bipolar transistor, 131 grounded emitters, its collector is electrically connected this second input end 102 by the 3rd biasing resistor 139.These second bipolar transistor, 133 base stages are electrically connected this first bipolar transistor, 131 collectors, these second bipolar transistor, 133 grounded emitters, and its collector is by these soft start capacitor 19 ground connection.
This pulse width adjusting circuit 15 comprises an input end 151 and an output terminal 153, and this input end 151 is electrically connected these second bipolar transistor, 133 collectors, and its output terminal 153 is electrically connected this inverter 17.This pulse width adjusting circuit 15 can be integrated circuit (IC) 805.
This second input end 102 loads a positive 5V DC voltage, and this 5V DC voltage provides a base bias voltage for these second bipolar transistor, 133 base stages by the 3rd biasing resistor 139.When starting working by this display controller 11 of a software setting, this output terminal 113 outputs one 3.3V high level, when this display controller 11 quits work, this output terminal 113 outputs one 0V low level.
When the user presses the power switch of liquid crystal indicator, when opening this liquid crystal indicator, this power switch produces a power supply and opens signal, and is loaded on this first input end 101.The input end 111 of this display controller 11 receives starts working after this power supply is opened signal, this output terminal 113 outputs one 3.3V high level, this 3.3V high level is loaded on this first bipolar transistor, 131 base stages by this first biasing resistor 135, these first bipolar transistor, 131 conductings, these second bipolar transistor, 133 base stages become low level, this second bipolar transistor 133 ends, and its current collection is high-impedance state very.The internal current source of this pulse width adjusting circuit 15 is to these soft start capacitor 19 chargings, and its duration of charging is about 450us by measurement.When these soft start capacitor 19 charging voltages are higher than triggering level (this triggering level is 2V), this pulse width adjusting circuit 15 is started working, and drives this control inverter backlight 17 to light the backlight of this liquid crystal indicator.
When the user presses the power switch of this liquid crystal indicator, when closing this liquid crystal indicator, this power switch produces a power supply and closes signal, and is loaded on this first input end 101.The input end 111 of this display controller 11 receives and quits work after this power supply closes signal, this output terminal 113 outputs one 0V low level, these first bipolar transistor, 131 base stages become low level, this first bipolar transistor 131 ends, these second bipolar transistor, 133 base stages are high level by drawing on this positive 5V DC voltage, these second bipolar transistor, 133 conductings, these second bipolar transistor, 133 collectors become low level, this soft start capacitor 19 is by the collector of this second bipolar transistor 133, the emitter discharge, input end 151 voltages of this pulse width adjusting circuit 15 slowly descend and stop to send control signals to this inverter 17 up to this pulse width adjusting circuit 15, this control inverter 17 backlight quits work, and the backlight of this liquid crystal indicator closed.
But, the conducting of this first, second bipolar transistor 131,133 of SS (soft start) control circuit 13 usefulness of this power circuit 10 with end the charge and discharge of controlling this soft start capacitor 19, the electronic component number of this SS (soft start) control circuit 13 is more, the circuit structure more complicated, printed circuit board (PCB) (Printed Circuit Board, PCB) Bu Xian complexity have been increased.And since this first, second bipolar transistor the 131, the 133rd, current controling element, need provide extra positive 5V direct supply to keep its operate as normal as bias voltage, the existence of positive 5V direct current supply line also produces noise to the electronic component around it in this printed circuit board (PCB), influences the stability of this power circuit.
Summary of the invention
In order to solve circuit construction of electric power complexity in the prior art, problem that noise is big, the invention provides a kind of power circuit of simplifying circuit structure, reducing noise.
A kind of power circuit, it comprises a display controller, one pulse width adjusting circuit, one soft start capacitor, an one control liquid crystal indicator inverter and a filter capacitor backlight, this display controller comprises an output terminal, the output terminal of this display controller is by this filter capacitor ground connection, this pulse width adjusting circuit comprises an input end and an output terminal, this pulse width adjusting circuit input end is by this soft start capacitor ground connection, its output terminal is electrically connected this inverter, wherein, this power circuit also comprises a field-effect transistor, this field-effect transistor grid is electrically connected this display controller output terminal, its source ground, its drain electrode is electrically connected this pulse width adjusting circuit input end.
Compared with prior art, power circuit of the present invention with this field-effect transistor by controlling the charge and discharge of this soft start capacitor with conducting, compare with the SS (soft start) control circuit that two bipolar transistors and three biasing resistors constitute with the power circuit of prior art, reduced the number of electronic component, simplified circuit structure, the wiring of the printed circuit board (PCB) of this power circuit is more prone to.And because this field-effect transistor is to control drain electrode and source electrode by the height of grid voltage, do not need extra power supply to provide operating voltage for this field-effect transistor, therefore do not need extra power lead to be connected to this field-effect transistor in this printed circuit board (PCB), thereby reduced the noise of this power circuit, helped the raising of this power circuit performance.This power circuit is than the power circuit electronic component decreased number of prior art simultaneously, and power consumption reduces.
Description of drawings
Fig. 1 is a kind of synoptic diagram of prior art power circuit.
Fig. 2 is the synoptic diagram of power circuit of the present invention.
Embodiment
Seeing also Fig. 2, is the synoptic diagram of power circuit of the present invention.This power circuit 20 comprises an input end 201, a display controller 21, a filter capacitor 22, a field-effect transistor 23, a pulse width adjusting circuit 25, an inverter 27 and a soft start capacitor 29.This display controller 21 comprises an input end 211 and an output terminal 213, and this display controller 21 can be integrated circuit GM5621.This pulse width adjusting circuit 25 comprises an input end 251 and an output terminal 253.This pulse width adjusting circuit 25 can be integrated circuit (IC) 805.This field-effect transistor 23 is a N channel enhancement MOS field-effect transistor, and its model is RK7002.
This input end 201 is electrically connected the input end 211 of this display controller 21, and the output terminal 213 of this display controller 21 is by these filter capacitor 22 ground connection.
These field-effect transistor 23 grids are electrically connected this display controller 21 output terminals 213, its source ground, and its drain electrode is by these soft start capacitor 29 ground connection.
These pulse width adjusting circuit 25 input ends 251 are electrically connected this field-effect transistor 23 drain electrodes, and its output terminal 253 is electrically connected this inverter 27.
When starting working, this output terminal 213 is exported a 0V low level by this display controller 21 of a software setting, and this display controller 21 is when quitting work, and this output terminal 213 is exported a 3.3V high level.
When the user presses the power switch of liquid crystal indicator, when opening this liquid crystal indicator, this power switch produces a power supply and opens signal, and is loaded on this input end 201.The input end 211 of this display controller 21 receives starts working after this power supply is opened signal, its output terminal 213 outputs one 0V low level, these field-effect transistor 23 grids become low level, this field-effect transistor 23 ends, its drain electrode is high-impedance state, the internal current source of this pulse width adjusting circuit 25 is to these soft start capacitor 29 chargings, and its duration of charging is about 450us by measurement.When these soft start capacitor 29 charging voltages are higher than triggering level (this triggering level is 2V), this pulse width adjusting circuit 25 is started working, and drives this control inverter backlight 27 to light the backlight of this liquid crystal indicator.
When the user presses the power switch of this liquid crystal indicator, when closing this liquid crystal indicator, this power switch produces a power supply and closes signal, and is loaded on this input end 201.The input end 211 of this display controller 21 receives and quits work after this power supply closes signal, its output terminal 213 outputs one 3.3V high level, these field-effect transistor 23 grids become high level, these field-effect transistor 23 conductings, its drain electrode becomes low level, promptly the input end 251 of this pulse width adjusting circuit 25 is a low level, this soft start capacitor 29 is by the drain electrode of this field-effect transistor 23, the source electrode discharge, input end 251 voltages of this pulse width adjusting circuit 25 slowly descend and stop to send control signals to this inverter 27 up to this pulse width adjusting circuit 25, this control inverter 27 backlight quits work, and the backlight of this liquid crystal indicator closed.
Compared with prior art, the charge and discharge of this soft start capacitor 29 is controlled in end and the conducting of this field-effect transistor 23 of power circuit 20 usefulness of the present invention, compare with the SS (soft start) control circuit that prior art power circuit 10 usefulness, two bipolar transistors and three biasing resistors constitute, reduced the number of electronic component, simplified circuit structure, the wiring of the printed circuit board (PCB) of this power circuit 20 is more prone to.And because this field-effect transistor 23 is to control drain electrode and source electrode by the height of grid voltage, do not need extra power supply to provide operating voltage for this field-effect transistor 23, therefore do not need extra power lead to be connected to this field-effect transistor 23 in this printed circuit board (PCB), thereby reduced the noise of this power circuit 20, helped the raising of these power circuit 20 stabilities.This power circuit 20 is than the power circuit 10 electronic component decreased number of prior art simultaneously, and its power consumption reduces.
Claims (7)
1. power circuit, it comprises a display controller, one pulse width adjusting circuit, one soft start capacitor, an one control liquid crystal indicator inverter and a filter capacitor backlight, this display controller comprises an output terminal, the output terminal of this display controller is by this filter capacitor ground connection, this pulse width adjusting circuit comprises an input end and an output terminal, this pulse width adjusting circuit input end is by this soft start capacitor ground connection, its output terminal is electrically connected this inverter, it is characterized in that: this power circuit also comprises a field-effect transistor, this field-effect transistor grid is electrically connected this display controller output terminal, its source ground, its drain electrode is electrically connected this pulse width adjusting circuit input end.
2. power circuit as claimed in claim 1 is characterized in that: this pulse width adjusting circuit drives this inverter to light or to close the backlight of this liquid crystal indicator.
3. power circuit as claimed in claim 2 is characterized in that: when this display controller is started working, and output 0V low level; When quitting work, output 3.3V high level.
4. power circuit as claimed in claim 1 is characterized in that: this field-effect transistor is a N channel enhancement MOS field-effect transistor.
5. power circuit as claimed in claim 4 is characterized in that: this field-effect transistor model is RK7002.
6. power circuit as claimed in claim 1 is characterized in that: this display controller is integrated circuit GM5621.
7. power circuit as claimed in claim 1 is characterized in that: this pulse width adjusting circuit is an integrated circuit (IC) 805.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100645859A CN100529858C (en) | 2006-12-29 | 2006-12-29 | Electric power circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2006100645859A CN100529858C (en) | 2006-12-29 | 2006-12-29 | Electric power circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101211030A CN101211030A (en) | 2008-07-02 |
| CN100529858C true CN100529858C (en) | 2009-08-19 |
Family
ID=39611168
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2006100645859A Expired - Fee Related CN100529858C (en) | 2006-12-29 | 2006-12-29 | Electric power circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100529858C (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103051232B (en) * | 2012-12-07 | 2015-10-21 | 京东方科技集团股份有限公司 | A kind of inverter and display unit |
| CN103295538B (en) * | 2013-07-02 | 2015-03-04 | 深圳市华星光电技术有限公司 | Backlight drive circuit and method for shortening soft starting time of backlight drive circuit |
| CN110910848A (en) | 2019-11-28 | 2020-03-24 | Tcl华星光电技术有限公司 | Driving circuit and driving method of liquid crystal display |
| CN117031346A (en) * | 2023-07-28 | 2023-11-10 | 深圳凌扬微电子有限公司 | Quick test circuit and device for power supply equipment |
-
2006
- 2006-12-29 CN CNB2006100645859A patent/CN100529858C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN101211030A (en) | 2008-07-02 |
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| Date | Code | Title | Description |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090819 Termination date: 20191229 |