CN201266984Y - Detection circuit for LCD-TV power supply - Google Patents
Detection circuit for LCD-TV power supply Download PDFInfo
- Publication number
- CN201266984Y CN201266984Y CNU2008202129746U CN200820212974U CN201266984Y CN 201266984 Y CN201266984 Y CN 201266984Y CN U2008202129746 U CNU2008202129746 U CN U2008202129746U CN 200820212974 U CN200820212974 U CN 200820212974U CN 201266984 Y CN201266984 Y CN 201266984Y
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- China
- Prior art keywords
- power supply
- resistance
- lcd
- triode
- voltage
- Prior art date
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- Liquid Crystal Display Device Control (AREA)
Abstract
The utility model discloses a testing circuit applied to an LCD-TV power supply, comprising a standby chip, an MOS tube Q2 connected with the standby chip, a triode Q1 connected with the MOS tube Q2, and a diode D1, a first resistance R1, a second resistance R2 and a third resistance R3 which are connected with alternating current input voltage. The alternating current input voltage is tested by a voltage testing network, under the condition that the input alternating current voltage input by a grid is lower than reliable voltage, a switch network which consists of an NPN triode Q1 and an N channel MOS tube Q2 is controlled by resistance sampling after the alternating current voltage is rectified so as to lead the standby chip to feed back or a soft start pin to be grounded instantly (low voltage), then, the chip is protected, and the work is stopped, thereby ensuring the stability of a power supply and improving the performance of the television.
Description
[technical field]
The utility model relates to technical field of television sets, particularly a kind of testing circuit that is applied on the LCD-TV power supply.
[background technology]
In order to guarantee the safe, reliable, durable in use of LCD-TV power supply, must make under its condition of work that is operated in circuit requirement, but often owing to there are the many factors that can not predict (electrical network factor or circuit working are unusual etc.) to force power work under off rating.For example: mains supply deficiency, power supply department are taked the step-down power supply, or remote area, and loss is too much, causes alternating voltage on the low side, thereby causes the load cisco unity malfunction.Can cause power supply reliability to descend under the situation of permanent load cisco unity malfunction, the harm that power source life shortens is so the design of testing circuit is an important key link.
[utility model content]
For addressing the above problem, main purpose of the present utility model is to provide the testing circuit on a kind of LCD-TV of being applied to power supply.
For achieving the above object, the technical solution of the utility model is:
A kind of testing circuit that is applied on the LCD-TV power supply includes and treats machine chip, connects and to treat the metal-oxide-semiconductor Q2 of machine chip, the triode Q1 that is connected with metal-oxide-semiconductor Q2 and to connect diode D1 that interchange imports and first, second, third resistance R 1, R2, R3.
Further, described triode Q1 is NPN type triode Q1, and its base stage connects interchange by one the 5th resistance R 5 and detects the voltage sample point.
Further, exchange detecting voltage sample point also is connected with by the 4th resistance R 4 RC parallel circuits in parallel with first capacitor C 1, this RC parallel circuits other one section and triode Q1 emitter common ground.
Further, described metal-oxide-semiconductor Q2 is N-channel MOS pipe Q2, and the collector electrode of triode Q1 is connected with N-channel MOS pipe Q2 grid (G), and connects the VCC supply network by one the 6th resistance R 6.
Compared to prior art; the testing circuit that the utility model is applied on the LCD-TV power supply passes through voltage detecting network measuring AC-input voltage; be lower than at the electrical network input ac voltage under the situation of reliable voltage; with the switching network of forming by NPN triode Q1 and N-channel MOS pipe Q2 by resistance sampling control behind the ac voltage rectifier; make and to treat machine chip feedback or soft start pin moment (low level) over the ground; the chip protection; quit work; thereby guaranteed the stability of power supply, improved the performance of television set.
[description of drawings]
Fig. 1 is applied to the circuit theory diagrams of the testing circuit on the LCD-TV power supply for the utility model.
[embodiment]
See also shown in Figure 1, a kind of testing circuit that is applied on the LCD-TV power supply of the utility model includes and treats machine chip, connects and to treat machine chip feedback or the N-channel MOS pipe Q2 of soft start pin, the triode Q1 that is connected with N-channel MOS pipe Q2 and to connect diode D1 that interchange imports and first, second, third resistance R 1, R2, R3.Wherein, described triode Q1 is NPN type triode Q1, its base stage connects interchange by one the 5th resistance R 5 and detects voltage sampling point A, sampled point A also is connected with by the 4th resistance R 4 RC parallel circuits in parallel with first capacitor C 1, this RC parallel circuits other one section with triode Q1 emitter common ground.The collector electrode of triode Q1 is connected with N-channel MOS pipe Q2 grid (G), and connects the VCC supply network by one the 6th resistance R 6.N-channel MOS pipe Q2 grid (G) also is connected with the RC circuit of being made up of the 7th resistance R 7 and second capacitor C 2.In addition, N-channel MOS pipe Q2 drain electrode (D) reception machine chip feedback pin or soft start pin (choosing suitable protection pin), and N-channel MOS pipe Q2 source electrode (S) ground connection according to chip characteristics.
Under the situation of mains supply voltage conforms LCD-TV power work condition (promptly being not less than 110V), AC-input voltage is through over commutation and resistance sampling, make NPN triode Q1 base stage that the input of 0.7V level be arranged, thereby saturation conduction, this moment, collector potential was dragged down, low level can't make the gate turn-on of N-channel MOS pipe Q2, and stand-by circuit is for normal operating conditions.When power work in off rating following time; AC-input voltage descends; when being lower than certain value (be provided with parameter with 110V as the reference point); AC-input voltage is through diode D1 rectification and pull-up resistor (i.e. first resistance; second resistance; the 3rd resistance R 1; R2; R3) and after pull down resistor (i.e. the 4th resistance R 4) sampling; can't make NPN three pipe Q1 conductings (base potential is lower than 0.7V); this moment, network was given the collector electrode of NPN triode Q1 and the gate turn-on high level of N-channel MOS pipe Q2 simultaneously; N-channel MOS pipe Q2 saturation conduction; to treat that machine chip feedback or soft start pin are pulled to electronegative potential; treat that machine chip starts defencive function immediately; quit work; power supply is not worked, and makes power supply be in guard mode.
By voltage detecting network measuring AC-input voltage; be lower than at the electrical network input ac voltage under the situation of reliable voltage; to control the switching network of forming by NPN triode Q1 and N-channel MOS pipe Q2 by resistance sampling behind the ac voltage rectifier; make and to treat machine chip feedback or soft start pin moment (low level) over the ground; the chip protection; quit work, thereby guaranteed the stability of power supply, improved the performance of television set.
Most preferred embodiment described above only is that the utility model is set forth and illustrated, but is not limited to disclosed any concrete form, and it is possible carrying out many modifications and variations.
Claims (6)
1. testing circuit that is applied on the LCD-TV power supply, include and treat to it is characterized in that machine chip: also include to connect and treat the metal-oxide-semiconductor Q2 of machine chip, the triode Q1 that is connected with metal-oxide-semiconductor Q2 and to connect diode D1 that interchange imports and first, second, third resistance R 1, R2, R3.
2. the testing circuit that is applied on the LCD-TV power supply as claimed in claim 1 is characterized in that: described triode Q1 is NPN type triode Q1, and its base stage connects interchange by one the 5th resistance R 5 and detects the voltage sample point.
3. the testing circuit that is applied on the LCD-TV power supply as claimed in claim 2, it is characterized in that: exchange to detect voltage sample point and also be connected with by the 4th resistance R 4 RC parallel circuits in parallel, this RC parallel circuits other one section and triode Q1 emitter common ground with first capacitor C 1.
4. the testing circuit that is applied on the LCD-TV power supply as claimed in claim 3, it is characterized in that: described metal-oxide-semiconductor Q2 is N-channel MOS pipe Q2, the collector electrode of triode Q1 is connected with N-channel MOS pipe Q2 grid (G), and connects the VCC supply network by one the 6th resistance R 6.
5. the testing circuit that is applied on the LCD-TV power supply as claimed in claim 4 is characterized in that: described metal-oxide-semiconductor Q2 grid (G) also is connected with the RC circuit of being made up of the 7th resistance R 7 and second capacitor C 2.
6. the testing circuit that is applied on the LCD-TV power supply as claimed in claim 5 is characterized in that: described metal-oxide-semiconductor Q2 drain electrode (D) reception machine chip feedback pin or soft start pin, and N-channel MOS pipe Q2 source electrode (S) ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008202129746U CN201266984Y (en) | 2008-10-13 | 2008-10-13 | Detection circuit for LCD-TV power supply |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU2008202129746U CN201266984Y (en) | 2008-10-13 | 2008-10-13 | Detection circuit for LCD-TV power supply |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201266984Y true CN201266984Y (en) | 2009-07-01 |
Family
ID=40833355
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU2008202129746U Expired - Fee Related CN201266984Y (en) | 2008-10-13 | 2008-10-13 | Detection circuit for LCD-TV power supply |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201266984Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101742188B (en) * | 2009-12-31 | 2013-06-12 | 深圳创维－Rgb电子有限公司 | LCD (Liquid Crystal Display)-TV power supply voltage detection circuit |
| CN103795386A (en) * | 2014-02-26 | 2014-05-14 | 天地融科技股份有限公司 | Control circuit |
| CN104394406A (en) * | 2014-11-19 | 2015-03-04 | 四川长虹电器股份有限公司 | Detection system and method applicable to AC startup and shutdown test of television |
-
2008
- 2008-10-13 CN CNU2008202129746U patent/CN201266984Y/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101742188B (en) * | 2009-12-31 | 2013-06-12 | 深圳创维－Rgb电子有限公司 | LCD (Liquid Crystal Display)-TV power supply voltage detection circuit |
| CN103795386A (en) * | 2014-02-26 | 2014-05-14 | 天地融科技股份有限公司 | Control circuit |
| CN103795386B (en) * | 2014-02-26 | 2017-02-22 | 天地融科技股份有限公司 | Control circuit |
| CN104394406A (en) * | 2014-11-19 | 2015-03-04 | 四川长虹电器股份有限公司 | Detection system and method applicable to AC startup and shutdown test of television |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20090701 Termination date: 20151013 |
|
| EXPY | Termination of patent right or utility model |