CN201813316U - Power switching circuit - Google Patents
Power switching circuit Download PDFInfo
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- CN201813316U CN201813316U CN2010205672750U CN201020567275U CN201813316U CN 201813316 U CN201813316 U CN 201813316U CN 2010205672750 U CN2010205672750 U CN 2010205672750U CN 201020567275 U CN201020567275 U CN 201020567275U CN 201813316 U CN201813316 U CN 201813316U
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- voltage
- chip
- circuit
- liquid crystal
- power
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Abstract
The utility model discloses a power switching circuit, relates to the field of liquid crystal display, and aims to solve the problem of higher cost for generating analog voltage (AVDD) for driving the liquid crystal by a direct current to direct current (DC/DC) booster circuit in the prior art. The power switching circuit comprises a power supply and a low dropout regulator (LDO), wherein a voltage output end of the power supply is connected with a voltage input end of the LDO; and a voltage output end of the LDO outputs the AVDD and is connected with a chip for driving the liquid crystal inside a liquid crystal display panel. The power switching circuit can be used for a liquid crystal display device.
Description
Technical field
The utility model relates to field of liquid crystal display, relates in particular to a kind of power-switching circuit.
Background technology
In the existing liquid crystal indicator, the power supply that two-in-one LIPS power supply provides for the chip of liquid crystal in the driving display panels, described 5V of LIPS power supply output or 12V power supply offer panel driving, and panel driving produces a voltage AVDD who drives liquid crystal by the DC/DC booster circuit that a direct current becomes in the direct current DC/DC chip.
In the process that realizes embodiment of the present utility model, the inventor finds that higher by the circuit cost of the generation of the DC/DC booster circuit in DC/DC chip AVDD in the prior art, the cost of described DC/DC chip is higher, and the peripheral components of this chip is also many.
The utility model content
The utility model provides a kind of power-switching circuit, becomes the voltage AVDD cost problem of higher that direct current DC/DC booster circuit produces a driving liquid crystal to solve the available technology adopting direct current.
For solving the problems of the technologies described above, the utility model adopts following technical scheme:
A kind of power-switching circuit, comprise power supply and low pressure difference linear voltage regulator LDO, described power source voltage output links to each other with the voltage input end of described LDO, and the voltage output end of described LDO is exported AVDD, and is connected with the chip of liquid crystal in the driving display panels.
In the prior art, also comprise a charge pump circuit in the described DC/DC chip, produce a voltage Von and a Voff who drives Thin Film Transistor (TFT) TFT switch by described charge pump circuit, for opening and closing the gate voltage of TFT, described power-switching circuit, also comprise: Thin Film Transistor (TFT) TFT drive circuit, the voltage input end of described TFT drive circuit is connected with described power source voltage output, and the voltage output end of described TFT drive circuit is connected with TFT.
Concrete, described TFT drive circuit comprises chip and the switch DC booster circuit that the PWM ripple is provided, the waveform output of the chip of the described PWM of providing ripple is connected with switch in the described switch DC booster circuit, and the voltage input end of described switch DC booster circuit is connected with described power source voltage output.
Or, concrete, described TFT drive circuit comprises chip and the charge pump circuit that the PWM ripple is provided, and the waveform output of the chip of the described PWM of providing ripple is connected with switch arrays in the described charge pump circuit, and the voltage input end of described charge pump circuit is connected with described power source voltage output.Inductance has been avoided in described charge pump circuit inside, thereby has avoided because the inductance that comprises in the switch DC booster circuit produces electromagnetic radiation produces electromagnetic interference to the device in the circuit problem.
Further, in order to reduce the device number, save cost, the chip of the described PWM of providing ripple is the master chip of image processing system in the liquid crystal indicator.
The power-switching circuit that the utility model embodiment provides, the voltage that power supply provides is by producing a voltage AVDD who drives liquid crystal by low pressure difference linear voltage regulator LDO, the cost of described LDO is low, noise is low, quiescent current is little, and the peripheral components that LDO needs also seldom, only needs one or two shunt capacitance usually, produces a voltage AVDD cost problem of higher that drives liquid crystal thereby solved available technology adopting direct current change direct current DC/DC booster circuit.
Description of drawings
The Organization Chart of the power-switching circuit that Fig. 1 provides for the utility model embodiment;
The Organization Chart one of the power-switching circuit that Fig. 2 provides for the another embodiment of the utility model;
The Organization Chart two of the power-switching circuit that Fig. 3 provides for the another embodiment of the utility model;
Fig. 4 is the circuit diagram of switch DC booster circuit in the power-switching circuit shown in Fig. 3;
Fig. 4 (a) is a PWM ripple oscillogram;
The Organization Chart three of the power-switching circuit that Fig. 5 provides for the another embodiment of the utility model;
Fig. 6 is the circuit diagram of charge pump circuit in the power-switching circuit shown in Figure 5.
Embodiment
The utility model aims to provide a kind of power-switching circuit, has solved the available technology adopting direct current and has become the voltage AVDD cost problem of higher that direct current DC/DC booster circuit produces a driving liquid crystal.
In order to enable those skilled in the art to understand the utility model scheme better, and above-mentioned purpose of the present utility model, feature and advantage can be become apparent more, the present invention is elaborated below in conjunction with drawings and Examples.
As shown in Figure 1, the power-switching circuit that provides of the utility model embodiment comprises power supply 101 and low pressure difference linear voltage regulator LDO102.
Described power supply 101 is used for providing voltage to described LDO102, and the voltage output end of described power supply 101 links to each other with the voltage input end of described LDO102.Described power supply 101 can be a single supply, also can be two-in-one LIPS power supply.When described power supply 101 was single supply, described single-power voltage what deserves to be explained is that than the high suitable voltage of voltage AVDD voltage that drives liquid crystal the difference between described single-power voltage and the described AVDD is the smaller the better.And when described power supply 101 was the LIPS power supply, described LIPS power supply generation+5V and high voltage High VCC, described High VCC were than the high suitable voltage of voltage AVDD voltage that drives liquid crystal, and High VCC is by forming AVDD after the LDO102.
Described LDO102 is used for providing voltage to the chip that drives the display panels liquid crystal, and the voltage output end of described LDO102 is exported AVDD, and is connected with the chip 103 of liquid crystal in the driving display panels.
The output noise 30 μ V of described LDO, Power Supply Rejection Ratio PSRR is 60dB, quiescent current 6 μ A, voltage drop has only 100mV.Why the performance of LDO linear voltage regulator can reach this level, and main cause is that adjustment pipe wherein is with P channel metal-oxide layer-semiconductor-field-effect transistor MOSFET, and common linear voltage regulator is to use the PNP triode.The PNP triode is a Current Control, and the P channel mosfet is voltage-controlled, so greatly reduce the consumed current of device own; On the other hand, adopt in the transistorized circuit of PNP, reduce fan-out capability in order to prevent the PNP transistor from entering saturation condition, the voltage drop between the input and output is can not ether low; And the voltage drop on the P channel mosfet is substantially equal to the product of output current and conducting resistance.Because the conducting resistance of MOSFET is very little, thereby the voltage drop above it is very low.Input voltage and output voltage very near the time, select the LDO pressurizer for use, can reach very high efficient.
The power-switching circuit that the utility model embodiment provides, the voltage that power supply provides is by producing a voltage AVDD who drives liquid crystal by low pressure difference linear voltage regulator LDO, the cost of described LDO is low, noise is low, quiescent current is little, and the peripheral components that LDO needs also seldom, only needs one or two shunt capacitance usually, produces a voltage AVDD cost problem of higher that drives liquid crystal thereby solved available technology adopting direct current change direct current DC/DC booster circuit.
The power-switching circuit that provides with the another embodiment of the utility model is introduced described power-switching circuit in detail below.
As shown in Figure 2, the power-switching circuit that further embodiment of this invention provides comprises: power supply 201, low pressure difference linear voltage regulator LDO202 and Thin Film Transistor (TFT) TFT drive circuit 204.
Described power supply 201, be used for providing voltage to described LDO202 and described TFT drive circuit 204, the voltage output end of described power supply 201 links to each other with the voltage input end of described LDO202, and the voltage output end of described power supply 201 also links to each other with the voltage input end of described TFT drive circuit 204.
Described LDO202 is used for providing voltage to the chip that drives the display panels liquid crystal, and the voltage output end of described LDO202 is connected with the chip 203 of liquid crystal in the driving display panels.
Described TFT drive circuit 204 is used to produce voltage Von and the Voff that drives Thin Film Transistor (TFT) TFT205 switch, and the voltage output end of described TFT drive circuit 204 is connected with TFT205.
Concrete, as shown in Figure 3, described TFT drive circuit 204 comprises chip 301 and the switch DC booster circuit 302 that the PWM ripple is provided, the waveform output of the chip 301 of the described PWM of providing ripple is connected with switch in the described switch DC booster circuit 302, and the voltage input end of described switch DC booster circuit 302 is connected with the voltage output end of described power supply 201.
In the present embodiment, as shown in Figure 4, described switch DC booster circuit comprises inductance, electric capacity, diode and triode, described triode is connected with the chip waveform output of PWM ripple, and described PWM ripple is shown in Fig. 4 (a), at the high level of described PWM ripple, trigger described triode conducting, described switch DC booster circuit is in charging process, and at this moment, input voltage flows through inductance.Diode forward end ground connection so diode ends, is used to prevent that electric capacity from discharging over the ground.Because input is a direct current, so the electric current on the inductance increases so that certain ratio is linear, this ratio is relevant with the inductance size.Along with inductive current increases, some energy have been stored in the inductance.In the low level of described PWM ripple, described triode disconnects, and described switch DC booster circuit is in discharge process, because the electric current retention performance of inductance, the electric current of the inductance of flowing through can not become 0 at once, but the value when being finished by charging slowly becomes 0.And original circuit has disconnected, so inductance can only discharge by novel circuit, promptly inductance begins to the electric capacity charging, and the electric capacity both end voltage raises, and this moment, voltage was higher than input voltage.Boost and finish.The process of boosting is exactly the energy transfer process of an inductance.During charging, inductance absorbs energy, and inductance is emitted energy during discharge.If capacitance is enough big, just can in discharge process, keep a lasting electric current at output so.If the process of this break-make constantly repeats, just can obtain being higher than the voltage of input voltage at the electric capacity two ends.
Or, concrete, as shown in Figure 5, described TFT drive circuit 204 comprises chip 501 and the charge pump circuit 502 that the PWM ripple is provided, the waveform output of the chip 501 of the described PWM of providing ripple is connected with switch arrays in the described charge pump circuit 502, and the voltage input end of described charge pump circuit 502 is connected with the voltage output end of described power supply 201.
As shown in Figure 6, described charge pump circuit comprises chip, switch arrays and the electric capacity that the PWM ripple is provided, make described charge pump circuit inside avoid inductance like this, thereby avoided because the inductance that comprises in the switch DC booster circuit produces electromagnetic radiation produces electromagnetic interference to the device in the circuit problem.The chip that the PWM ripple can be provided is through behind the push-pull amplifier circuit, it is HIGH VCC that the PWM ripple becomes high pressure, low pressure is+the PWM ripple of 5V, for the VON loop, when PWM be+during 5V, diode D1 conducting, diode D2 ends, capacitor C 1 is charged, reach HIGH VCC-5V up to capacitor C 1 two ends pressure reduction, the voltage of load is kept in capacitor C 3 discharges; When PWM was HIGH VCC, because capacitance voltage can not suddenly change, A place voltage was 2HIGH VCC-5V, and diode D1 ends, diode D2 conducting, and the voltage at VON place is stabilized in 2HIGH VCC-5V through capacitor C 3 filtering, must be asked by VON and select HIGH VCC.
In like manner, for the VOFF loop, when PWM was HIGH VCC, diode D3 conducting was charged to capacitor C 2, reached HIGH VCC-5V up to capacitor C 2 two ends pressure reduction, and the voltage of load is kept in capacitor C 4 discharges; When PWM be+during 5V, because capacitance voltage can not suddenly change, B place voltage is 10V-HIGH VCC, diode D3 ends, diode D4 conducting, the voltage at VON place is stabilized in 10V-HIGH VCC. through capacitor C 4 filtering
Further, in order to reduce the device number, save cost, the chip of the described PWM of providing ripple can be the master chip of image processing system in the liquid crystal indicator.
The power-switching circuit that the utility model embodiment provides, the voltage that power supply provides is by producing a voltage AVDD who drives liquid crystal by low pressure difference linear voltage regulator LDO, the cost of described LDO is low, noise is low, quiescent current is little, and the peripheral components that LDO needs also seldom, only needs one or two shunt capacitance usually, produces a voltage AVDD cost problem of higher that drives liquid crystal thereby solved available technology adopting direct current change direct current DC/DC booster circuit.
The power supply changeover device that the utility model embodiment provides can be applicable to field of liquid crystal display.
The above; it only is embodiment of the present utility model; but protection range of the present utility model is not limited thereto; anyly be familiar with those skilled in the art in the technical scope that the utility model discloses; can expect easily changing or replacing, all should be encompassed within the protection range of the present utility model.Therefore, protection range of the present utility model should be as the criterion with the protection range of described claim.
Claims (5)
1. power-switching circuit, it is characterized in that comprise power supply and low pressure difference linear voltage regulator LDO, described power source voltage output links to each other with the voltage input end of described LDO, the voltage output end of described LDO is exported AVDD, and is connected with the chip of liquid crystal in the driving display panels.
2. power-switching circuit according to claim 1, it is characterized in that, also comprise Thin Film Transistor (TFT) TFT drive circuit, the voltage input end of described TFT drive circuit is connected with described power source voltage output, and the voltage output end of described TFT drive circuit is connected with TFT.
3. power-switching circuit according to claim 2, it is characterized in that, described TFT drive circuit comprises chip and the switch DC booster circuit that the PWM ripple is provided, the waveform output of the chip of the described PWM of providing ripple is connected with switch in the described switch DC booster circuit, and the voltage input end of described switch DC booster circuit is connected with described power source voltage output.
4. power-switching circuit according to claim 2, it is characterized in that, described TFT drive circuit comprises chip and the charge pump circuit that the PWM ripple is provided, the waveform output of the chip of the described PWM of providing ripple is connected with switch arrays in the described charge pump circuit, and the voltage input end of described charge pump circuit is connected with described power source voltage output.
5. according to claim 3 or 4 described power-switching circuits, it is characterized in that the chip of the described PWM of providing ripple is the master chip of image processing system in the liquid crystal indicator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010205672750U CN201813316U (en) | 2010-10-11 | 2010-10-11 | Power switching circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2010205672750U CN201813316U (en) | 2010-10-11 | 2010-10-11 | Power switching circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201813316U true CN201813316U (en) | 2011-04-27 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2010205672750U Expired - Lifetime CN201813316U (en) | 2010-10-11 | 2010-10-11 | Power switching circuit |
Country Status (1)
| Country | Link |
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| CN (1) | CN201813316U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014101077A1 (en) * | 2012-12-25 | 2014-07-03 | 深圳市华星光电技术有限公司 | Dc/dc module of lcd driving circuit |
| CN110311556A (en) * | 2019-06-27 | 2019-10-08 | 南京中电熊猫液晶显示科技有限公司 | A kind of power module, power control circuit and improves display panel and discharge insufficient method |
| CN115588415A (en) * | 2022-12-08 | 2023-01-10 | 禹创半导体(深圳)有限公司 | Driving chip for LCD panel power supply system and LCD panel |
-
2010
- 2010-10-11 CN CN2010205672750U patent/CN201813316U/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2014101077A1 (en) * | 2012-12-25 | 2014-07-03 | 深圳市华星光电技术有限公司 | Dc/dc module of lcd driving circuit |
| CN110311556A (en) * | 2019-06-27 | 2019-10-08 | 南京中电熊猫液晶显示科技有限公司 | A kind of power module, power control circuit and improves display panel and discharge insufficient method |
| CN110311556B (en) * | 2019-06-27 | 2020-08-04 | 南京中电熊猫液晶显示科技有限公司 | Power module, power control circuit and method for improving insufficient discharge of display panel |
| CN115588415A (en) * | 2022-12-08 | 2023-01-10 | 禹创半导体(深圳)有限公司 | Driving chip for LCD panel power supply system and LCD panel |
| CN115588415B (en) * | 2022-12-08 | 2023-02-28 | 禹创半导体(深圳)有限公司 | Driving chip for LCD panel power supply system and LCD panel |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| ASS | Succession or assignment of patent right |
Owner name: JINGDONGFANG SCIENCE AND TECHNOLOGY GROUP CO., LTD Free format text: FORMER OWNER: BEIJING BOE PHOTOELECTRICITY SCIENCE + TECHNOLOGY CO., LTD. Effective date: 20150702 Owner name: BEIJING BOE PHOTOELECTRICITY SCIENCE + TECHNOLOGY Effective date: 20150702 |
|
| C41 | Transfer of patent application or patent right or utility model | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20150702 Address after: 100015 Jiuxianqiao Road, Beijing, No. 10, No. Patentee after: BOE Technology Group Co., Ltd. Patentee after: Beijing BOE Photoelectricity Science & Technology Co., Ltd. Address before: 100176 Beijing economic and Technological Development Zone, West Central Road, No. 8 Patentee before: Beijing BOE Photoelectricity Science & Technology Co., Ltd. |
|
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20110427 |