CN208521588U - A kind of liquid crystal display power supply circuit and electronic device - Google Patents
A kind of liquid crystal display power supply circuit and electronic device Download PDFInfo
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- CN208521588U CN208521588U CN201820954802.XU CN201820954802U CN208521588U CN 208521588 U CN208521588 U CN 208521588U CN 201820954802 U CN201820954802 U CN 201820954802U CN 208521588 U CN208521588 U CN 208521588U
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- liquid crystal
- crystal display
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- power supply
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Abstract
The utility model provides a kind of liquid crystal display power supply circuit, comprising: input, output end, switching circuit and discharge circuit comprising concatenated discharge resistance and the first triode；Wherein, when switching circuit stops powering to liquid crystal display, the first triode ON is controlled, is discharged output end.Liquid crystal display power supply circuit and electronic device provided by the utility model are controlled discharge circuit and discharged when stopping and powering to liquid crystal display, ensure that timely electric discharge, so that liquid crystal display is normally shown using the discharge circuit with triode；In addition during liquid crystal display work and after the completion of electric discharge, discharge circuit does not work, so that discharge resistance will not generate additional power consumption and heat.
Description
Technical field
The utility model relates to automotive fields, and in particular to a kind of liquid crystal display power supply circuit and electronic device.
Background technique
Liquid crystal display (Liquid Crystal Display, LCD) is used more and more in combination instrument.To liquid crystal
Display screen power supply, using power supply circuit shown in FIG. 1, is powered, usually 3.3V DC power supply by power supply BAT.
When S2 driving signal is high level, the voltage between the base stage and emitter of the second triode T2 is greater than conducting threshold
Value, the second triode T2 conducting, so that the gate source voltage of third transistor T3 is greater than conduction threshold, third transistor T3 is connected,
Power supply BAT powers to liquid crystal display, and liquid crystal display is shown.
When S2 driving signal is low level, the second triode T2 is disconnected, and correspondingly third transistor T3 is disconnected, power supply
BAT no longer powers to liquid crystal display, and liquid crystal display does not work, i.e., no longer shows.
However, liquid crystal display is capacitive load, and after third transistor T3 is disconnected, the electricity of the output end Pout of power supply circuit
Pressure is not to drop to 0V at once, but slowly decline.
When vehicle ignition switch frequently switches on, combination instrument can be opened frequently, be closed, correspondingly the confession of liquid crystal display
Circuit also can control the second triode T2 by S2 driving signal, third transistor T3 is frequently connected, disconnects, in this process
In, it will cause liquid crystal display and show abnormal, such as partial region is not shown or messy code etc..
In order to guarantee that liquid crystal display is normally shown, conductive discharge can be used, physical circuit is as shown in Fig. 2, the three or three
After pole pipe T3 is disconnected, discharged by resistance R6, to guarantee that liquid crystal display is normally shown.
However resistance R6 also has power consumption when liquid crystal display works normally, thus increase the load of power supply BAT；Separately
Outer discharge time depends on the size of resistance R6, and resistance is smaller, discharges faster；But the size of resistance is held by the electric current of power supply BAT
The limitation of amount and pcb board fever, can not use resistance as small as possible.
Summary of the invention
Aiming at the problems existing in the prior art, problem to be solved in the utility model is to provide a kind of liquid crystal display confession
Circuit is controlled discharge circuit and discharged when stopping and powering to liquid crystal display, guaranteed using the discharge circuit with triode
Timely electric discharge, so that liquid crystal display is normally shown；In addition during liquid crystal display work and after the completion of electric discharge, electric discharge
Circuit does not work, so that discharge resistance will not generate additional power consumption and heat.
The utility model provides a kind of liquid crystal display power supply circuit, comprising:
Input terminal, for connecting DC power supply；
Output end, for powering to liquid crystal display；
Switching circuit is powered to liquid crystal display for controlling whether, is connected between input terminal and input terminal；
Discharge circuit, for output end electric discharge, including concatenated discharge resistance and the first triode；
Wherein, when switching circuit stops powering to liquid crystal display, the first triode ON is controlled, is discharged output end.
Further, switching circuit include the second triode, third transistor, first resistor and first capacitor, the two or three
The collector of pole pipe and the grid of third transistor connect, and are connect by first resistor with input terminal, and first capacitor is connected to the
Between the grid and drain electrode of three triodes；The source electrode of third transistor is connect with input terminal, and drain electrode is connect with output end.
Further, switching circuit includes the second triode, third transistor, first resistor, second resistance, first capacitor
The three or three pole is connected to first diode by the second resistance after parallel connection with the collector of first diode, the second triode
The grid of pipe, and connect by first resistor with input terminal；First capacitor is connected between the grid of third transistor and drain electrode,
The source electrode of third transistor is connect with input terminal, and drain electrode is connect with output end.
Further, it includes the second triode, third transistor, 3rd resistor, the 4th that switching circuit, which includes switching circuit,
Resistance, the 5th resistance and first capacitor, the collector of the second triode are connected to the grid of third transistor by the 4th resistance,
And it is connect by first resistor with input terminal；5th resistance is connected to grid and the source of third transistor after connecting with first capacitor
Between pole, the source electrode of third transistor is connect with input terminal, and drain electrode is connect with output end.
Further, the base stage of the first triode is connect with the collector of the second triode.
Further, discharge resistance is the resistance of multiple parallel connections.
The utility model also provides a kind of electronic device, including controller, liquid crystal display and above-mentioned liquid crystal display
Power supply circuit.
Further, the base stage access of the second triode of the switching circuit of liquid crystal display power supply circuit comes from controller
Driving signal.
Further, the base stage of the second triode of the switching circuit of liquid crystal display power supply circuit and liquid crystal display supply
The base stage of first triode of the discharge circuit of circuit, is respectively connected to the driving signal from controller.
Further, electronic device is combination instrument.
Compared with prior art, liquid crystal display power supply circuit and electronic device provided by the utility model have following
The utility model has the advantages that control discharge circuit discharges when stopping and powering to liquid crystal display using the discharge circuit with triode, protect
Timely electric discharge is demonstrate,proved, so that liquid crystal display is normally shown；In addition it during liquid crystal display work and after the completion of electric discharge, puts
Circuit does not work, so that discharge resistance will not generate additional power consumption and heat.
Detailed description of the invention
Fig. 1 is the liquid crystal display power supply circuit of existing discharge off circuit；
Fig. 2 is the existing liquid crystal display power supply circuit with conductive discharge；
Fig. 3 is the schematic diagram of the liquid crystal display power supply circuit of one embodiment of the utility model；
Fig. 4 is the schematic diagram of the liquid crystal display power supply circuit of another embodiment of the utility model；
Fig. 5 is the schematic diagram of the liquid crystal display power supply circuit of another embodiment of the utility model；
Fig. 6 is the schematic diagram of the liquid crystal display power supply circuit of another embodiment of the utility model.
Specific embodiment
Combination instrument includes controller, liquid crystal display and liquid crystal display power supply circuit, as shown in Figure 3, comprising:
Input terminal Pin, for connecting DC power supply BAT；
Output end Pout, for powering to liquid crystal display；
Switching circuit is powered for controlling whether to liquid crystal display, be connected to input terminal Pin and input terminal Pout it
Between；
Discharge circuit, for putting to output end Pout electric discharge, including concatenated discharge resistance R0 and the first triode T1
Resistance R0 is connected between output end Pout and the collector c of the first triode T1, and the emitter e of the first triode T1 connects
Ground；
Wherein, when switching circuit stops powering to liquid crystal display, control the first triode T1 conducting, to output end Pout
Electric discharge.
Switching circuit includes the second triode T2, third transistor T3, first resistor R1 and first capacitor C1, the two or three pole
The grid g of the collector c and third transistor T3 of pipe T2 are connect, and are connect by first resistor R1 with input terminal Pin, first capacitor
C1 is connected between the grid g of third transistor T3 and drain electrode d, and the emitter e of the second triode T2 is grounded；Third transistor T3
Source electrode s connect with input terminal Pin, drain electrode d connect with output end Pout.
The base stage b of second triode T2 of switching circuit accesses the driving signal S2 from controller.
The base stage b of first triode T1 of discharge circuit accesses the driving signal S1 from controller, and driving signal S1 exists
Close liquid crystal display when it is effective, that is, controller control switch circuit stop to liquid crystal display power when, control first
Triode T1 conducting, discharges to output end Pout.
By taking driving signal S1, S2 high level is effective as an example, illustrate the course of work of liquid crystal display power supply circuit:
When second triode T2 is disconnected, power supply BAT charges to first capacitor C1, after charging complete, third transistor T3's
Gate source voltage Vgs is 0V, and absolute value is less than conduction threshold, and third transistor T3 is disconnected, and power supply circuit stops to liquid crystal display
Power supply.
When S2 driving signal is high level, the voltage between the base stage b and emitter e of the second triode T2 is greater than conducting
Threshold value, the second triode T2 conducting；Due to being provided with first capacitor C1, the current potential of the grid g of third transistor T3 will not be immediately
Drop to and GND equipotential, first capacitor C1 electric discharge, so that the current potential of grid g declines；When the current potential of grid g declines so that grid
When the absolute value of source voltage Vgs is greater than conduction threshold, third transistor T3 conducting, power supply BAT powers to liquid crystal display at this time,
Liquid crystal display is shown.
Using such switching circuit, so that the voltage of output end Pout slowly rises, voltage is avoided to rise too fast cause
Dash current, to guarantee that power supply circuit reliably works.
When driving signal S2 is low level, controller issues the driving signal S1 of high level:
Low level driving signal S2 disconnects the second triode T2, and power supply BAT charges to first capacitor C1, works as third
The absolute value of the gate source voltage Vgs of triode T3 is less than conduction threshold, and third transistor T3 is disconnected, and power supply circuit stops to liquid crystal
Display screen power supply；
The first triode T1 is connected in the driving signal S1 of high level, and output end Pout is discharged by discharge resistance R0,
To guarantee that liquid crystal display is shown normally during frequent switching.
Using the discharge circuit with triode, controls discharge circuit and discharge when stopping and powering to liquid crystal display, protect
Timely electric discharge is demonstrate,proved, so that liquid crystal display is normally shown；In addition it during liquid crystal display work and after the completion of electric discharge, puts
Circuit does not work, so that discharge resistance R0 will not generate additional power consumption and heat.
In another embodiment, as shown in figure 4, the collector c of the base stage b of the first triode T1 and the second triode T2
Connection, as driving signal, is further simplified circuit, reduces costs.
In yet another embodiment, discharge resistance R0 is the resistance of multiple parallel connections, can guarantee pyrotoxin on pcb board in this way
Dispersion guarantees that power supply circuit safely and reliably works.
In yet another embodiment, as shown in figure 5, switching circuit includes the second triode T2, third transistor T3, first
Resistance R1, second resistance R2, first capacitor C1 and first diode D1, the second triode T2 collector c by after in parallel
Second resistance R2 and first diode D1 is connected to the grid g of third transistor T3, and passes through first resistor R1 and input terminal Pin
Connection, the emitter e ground connection of the second triode T2；First capacitor C1 be connected to third transistor T3 grid g and drain electrode d it
Between, the source electrode s of third transistor T3 is connect with input terminal Pin, and drain electrode d is connect with output end Pout.
In the present embodiment, when the second triode T2 is disconnected, power supply BAT is by first resistor R1 and first diode D1 to the
One capacitor C1 charging, the current potential of the grid g of third transistor T3 is gradually increasing from GND current potential, since first resistor R1 is much smaller than
Second resistance R2, charging current is larger, therefore being capable of quick charge.When the absolute value of the gate source voltage Vgs of third transistor T3
Less than conduction threshold, third transistor T3 is disconnected.
Using such circuit, third transistor T3 can be disconnected quickly.
In yet another embodiment, as shown in fig. 6, switching circuit includes the second triode T2, third transistor T3, third
The collector of resistance R3, the 4th resistance R4, the 5th resistance R5 and first capacitor C1, the second triode T2 are connected by the 4th resistance R4
It is connected to the grid of third transistor T3, and is connect by first resistor R1 with input terminal Pin, the emitter of the second triode T2 connects
Ground；5th resistance R5 is connected between the grid g of third transistor T3 and source electrode s after connecting with first capacitor C1, the three or three pole
The source electrode s of pipe T3 is connect with input terminal Pin, and drain electrode d is connect with output end Pout.
In yet another embodiment, the base stage b of the first triode T1 is connect with the collector c of the second triode T2, as
Driving signal is further simplified circuit, reduces costs.
The electronic device that liquid crystal display power supply circuit in above embodiments can be used for having liquid crystal display.
Although the utility model has been disclosed in the preferred embodiments as above, the utility model is not limited to this.Any
Field technical staff, made various changes and modification, should all be included in this without departing from the spirit and scope of the utility model
In the protection scope of utility model, therefore the protection scope of the utility model should be defined by the scope defined by the claims..
Claims (10)
1. a kind of liquid crystal display power supply circuit characterized by comprising
Input terminal, for connecting DC power supply；
Output end, for powering to liquid crystal display；
Switching circuit is powered to liquid crystal display for controlling whether, is connected between input terminal and input terminal；
Discharge circuit, for output end electric discharge, including concatenated discharge resistance and the first triode；
Wherein, when switching circuit stops powering to liquid crystal display, the first triode ON is controlled, is discharged output end.
2. liquid crystal display power supply circuit as described in claim 1, which is characterized in that switching circuit include the second triode,
The grid of third transistor, first resistor and first capacitor, the collector of the second triode and third transistor connects, by the
One resistance is connect with input terminal, and first capacitor is connected between the grid of third transistor and drain electrode；The source electrode of third transistor
It is connect with input terminal, drain electrode is connect with output end.
3. liquid crystal display power supply circuit as described in claim 1, which is characterized in that switching circuit include the second triode,
The collector of third transistor, first resistor, second resistance, first capacitor and first diode, the second triode passes through parallel connection
Second resistance and first diode afterwards is connected to the grid of third transistor, and is connect by first resistor with input terminal；The
Between the grid and drain electrode of third transistor, the source electrode of third transistor is connect one capacitance connection with input terminal, drain electrode with it is defeated
Outlet connection.
4. liquid crystal display power supply circuit as described in claim 1, which is characterized in that switching circuit includes that switching circuit includes
Second triode, third transistor, 3rd resistor, the 4th resistance, the 5th resistance and first capacitor, the collector of the second triode
It is connected to the grid of third transistor by the 4th resistance, and is connect by first resistor with input terminal；5th resistance and first
It is connected between the grid of third transistor and source electrode after capacitor series connection, the source electrode of third transistor is connect with input terminal, drain electrode
It is connect with output end.
5. such as the described in any item liquid crystal display power supply circuits of claim 2-4, which is characterized in that the base stage of the first triode
It is connect with the collector of the second triode.
6. liquid crystal display power supply circuit as described in claim 1, which is characterized in that discharge resistance is the electricity of multiple parallel connections
Resistance.
7. a kind of electronic device, which is characterized in that electronic device includes that controller, liquid crystal display and claim 1-6 appoint
Liquid crystal display power supply circuit described in one.
8. electronic device as claimed in claim 7, which is characterized in that the second of the switching circuit of liquid crystal display power supply circuit
The base stage of triode accesses the driving signal from controller.
9. electronic device as claimed in claim 7, which is characterized in that the second of the switching circuit of liquid crystal display power supply circuit
The base stage of first triode of the discharge circuit of the base stage and liquid crystal display power supply circuit of triode is respectively connected to from control
The driving signal of device.
10. electronic device as claimed in claim 7, which is characterized in that electronic device is combination instrument.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820954802.XU CN208521588U (en) | 2018-06-20 | 2018-06-20 | A kind of liquid crystal display power supply circuit and electronic device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820954802.XU CN208521588U (en) | 2018-06-20 | 2018-06-20 | A kind of liquid crystal display power supply circuit and electronic device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN208521588U true CN208521588U (en) | 2019-02-19 |
Family
ID=65325837
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201820954802.XU Active CN208521588U (en) | 2018-06-20 | 2018-06-20 | A kind of liquid crystal display power supply circuit and electronic device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN208521588U (en) |
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2018
- 2018-06-20 CN CN201820954802.XU patent/CN208521588U/en active Active
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