CN201041938Y - A LCD-TV power under-voltage protection circuit - Google Patents
A LCD-TV power under-voltage protection circuit Download PDFInfo
- Publication number
- CN201041938Y CN201041938Y CNU200720118661XU CN200720118661U CN201041938Y CN 201041938 Y CN201041938 Y CN 201041938Y CN U200720118661X U CNU200720118661X U CN U200720118661XU CN 200720118661 U CN200720118661 U CN 200720118661U CN 201041938 Y CN201041938 Y CN 201041938Y
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- resistance
- lcd
- voltage
- integrated chip
- triode
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Abstract
The utility model relates to an under voltage protective circuit for an LCD-TV. The circuit consists of a first resistance, a second resistance, a third resistance and a fourth resistance, a dynatron, a capacitance, a diode and an integrated chip. The base electrode of the dynatron is connected with the first and the second resistances respectively and furthermore, the first resistance is connected with dynatron. The other end of the dynatron is connected with the output end of the power supply and furthermore, the second resistance is connected with the ground. The collector of the dynatron is connected with the third and fourth resistances, the capacitance and the integrated chip respectively and furthermore, the fourth resistance and the capacitance are connected with the ground. The third resistance is connected with the power CPU that sends out control signals. The emitter of the dynatron is connected with the ground.
Description
Technical field
The utility model relates to electronic technology field, relates in particular to a kind of LCD-TV line under-voltage protective circuit.
Background technology
The design of protective circuit, important link in the power supply design beyond doubt, it is for all playing crucial effect in the security reliability that improves power work, useful life of prolonging power supply.When the design protection circuit, to guarantee its perfect in shape and function on the one hand, working stability is reliable; Should make every effort to simple and clear on the other hand, avoid complicated.
For guaranteeing whole usability and the reliability of LCD-TV, on properties of product, to realize the various states protection, as overvoltage, overcurrent, overvoltage etc.
The pwm circuit of common LCD-TV power supply all has the overpower protection function, and not or the overcurrent that has part ownership, overvoltage and under-voltage protection, as realizing that overcurrent, overvoltage and under-voltage protection function need add circuit in addition and realize.
The utility model content
In view of this, the utility model provides a kind of LCD-TV line under-voltage protective circuit, is mainly used on the LCD-TV power supply, and electric power output voltage is played a protective role when under-voltage, effectively protects other circuit and device.
A kind of LCD-TV line under-voltage protective circuit, wherein, this LCD-TV line under-voltage protective circuit mainly comprises first, second, third and fourth resistance, triode, electric capacity, diode, integrated chip; The base stage of triode connects first, second resistance respectively, and further first resistance links to each other with an end of diode, and the other end of diode connects the output of power supply, further second grounding through resistance; The collector electrode of triode connects the 3rd, the 4th resistance, electric capacity, integrated chip respectively, further the 4th resistance and the equal ground connection of electric capacity, and the 3rd resistance links to each other the grounded emitter of triode with the power supply CPU that sends control signal.
Described integrated chip links to each other with latching circuit
Compared with prior art; the utility model is by LCD-TV line under-voltage protective circuit; when output voltage less than protection during voltage, the diode of LCD-TV line under-voltage protective circuit ends, triode ends; the control signal of power supply CPU is charged to electric capacity; when capacitance voltage is charged to the conducting voltage of integrated chip, the integrated chip conducting, integrated chip provides control signal and makes the power supply no-output; play a protective role when under-voltage thereby reach, effectively protect other circuit and device electric power output voltage.
Description of drawings
Fig. 1 is a kind of LCD-TV line under-voltage protective circuit schematic diagram of the utility model better embodiment.
Embodiment
For the purpose, technical scheme, the advantage that make the utility model is clearer and more definite, clear, the technical scheme of the utility model is described in further detail below in conjunction with embodiment, accompanying drawing.
As shown in Figure 1; be a kind of LCD-TV line under-voltage of the utility model better embodiment protective circuit; mainly utilize triode and diode to carry out the protection of LCD-TV line under-voltage; this LCD-TV line under-voltage protective circuit mainly comprises resistance R 1, R2, R3, R4; triode Q1; capacitor C 1, diode ZD1, integrated chip IC1.
As shown in Figure 1, the annexation of this LCD-TV line under-voltage protective circuit is as described below: the base stage of triode Q1 connects resistance R 1 respectively, R2, and further resistance R 1 links to each other with diode ZD1, further resistance R 2 ground connection; The collector electrode of triode Q1 connects resistance R 3 respectively, R4, capacitor C 1, integrated chip IC1, further resistance R 4 and capacitor C 1 equal ground connection; The grounded emitter of triode Q1.
LCD-TV output has 24V, 12V, 5V etc., represents LCD-TV output with U1 among Fig. 1, and promptly diode ZD1 connects the output U1 of LCD-TV power supply, and ON/OFF is the CPU control signal, represents with U2, and the ON/OFF signal is provided by LCD-TV mainboard CPU.When being high level for ON, 24V, 12V should export normally; When being low level for OFF, 24V, 12V no-output.The output of integrated chip IC1 output control signal makes power supply output or output voltage U 1 not.
When output voltage U 1 normal output, the output voltage of U1 is during greater than 18V, diode ZD1 reverse-conducting then, triode Q1 conducting simultaneously, the ON/OFF signal arrives ground through resistance R 3 and triode Q1, and integrated chip IC1 does not start to control making usefulness, and integrated chip IC1 does not have control signal output, because integrated chip IC1 does not have control signal output, so U1 output is normal.
When the power supply operate as normal; output voltage U 1 output is normal; U1 voltage representative value is 24V; in output voltage U 1 during less than 18V; think under-voltage condition, for preventing to need power module to enter guard mode to being powered the own vigour device failure of device liquid crystal display screen and power supply; be under-voltage protection, for this 18V as the under-voltage protection point.
When the power supply operate as normal, output voltage U 1 is greater than 18V, the reverse-conducting of diode ZD1 then, triode Q1 conducting simultaneously, the ON/OFF signal arrives ground through resistance R 3 and triode Q1, and integrated chip IC1 does not start to control making usefulness, and integrated chip IC1 does not have control signal output, because integrated chip IC1 does not have control signal output, so U1 output is normal.
When the power supply operate as normal; output voltage U 1 is about 24; greater than under-voltage protection trigger point 18V; wherein diode ZD1 is the 15V voltage stabilizing didoe; then the neat sodium of diode ZD1 punctures; provide base current for triode Q1 simultaneously; make the BE conducting of triode Q1; ON/OFF signal voltage U2 arrives ground through resistance R 3 and triode Q1; wherein the ON/OFF signal is provided by LCD-TV mainboard CPU; output voltage is between 2.5 to 4.2V, and the saturation voltage drop of triode Q1 is the end relatively, and deficiency is so that the diode current flow of integrated chip IC1; integrated chip IC1 did not start to control to make and used this moment; integrated chip IC1 does not have control signal output, because integrated chip IC1 does not have control signal output, institute is so that U1 output is normal.Wherein integrated chip IC1 links to each other with latching circuit, and when the diode current flow of integrated chip IC1, ON/OFF signal voltage U2 is 0V; When the not conducting of diode of integrated chip IC1, ON/OFF signal voltage U2 is (concrete numerical value is determined by CPU) between 2.5 to 4.2V.
When output voltage U 1 is exported less than 18V, diode ZD1 ends, triode Q1 ends, U2 is through 1 charging of 3 pairs of capacitor C of resistance R, when capacitor C 1 voltage is charged to the conducting voltage of integrated chip IC1, integrated chip IC1 conducting, integrated chip IC1 provides control signal, (preventing misoperation herein when capacitor C 1 is used for normal boot-strap), the control signal that integrated chip IC1 provides make power supply U1 no-output.
Can change the parameter of diode ZD1, adjust the under-voltage protection point, can change capacitor C 1, adjust between time-delay, prevent misoperation, component parameters can adjust accordingly according to concrete application among Fig. 1.
When realizing overcurrent protection, need to realize that when overcurrent increases, output voltage is reduced, when output voltage U 1 reached under-voltage protection point, circuit protection made the U1 no-output in conjunction with overpower protection.
Though the utility model is described with reference to current better embodiment; but those skilled in the art will be appreciated that; above-mentioned better embodiment only is used for illustrating the utility model; be not to be used for limiting protection range of the present utility model; any within spirit of the present utility model and principle scope; any modification of being done, equivalence replacement, improvement etc. all should be included within the rights protection scope of the present utility model.
Claims (2)
1. LCD-TV line under-voltage protective circuit, it is characterized in that: this LCD-TV line under-voltage protective circuit mainly comprises first, second, third and fourth resistance, triode, electric capacity, diode, integrated chip; The base stage of triode connects first, second resistance respectively, and further first resistance links to each other with an end of diode, and the other end of diode connects the output of power supply, further second grounding through resistance; The collector electrode of triode connects the 3rd, the 4th resistance, electric capacity, integrated chip respectively, further the 4th resistance and the equal ground connection of electric capacity, and the 3rd resistance links to each other the grounded emitter of triode with the power supply CPU that sends control signal.
2. profit requires 1 described LCD-TV line under-voltage protective circuit, and it is characterized in that: described integrated chip links to each other with latching circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU200720118661XU CN201041938Y (en) | 2007-02-12 | 2007-02-12 | A LCD-TV power under-voltage protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNU200720118661XU CN201041938Y (en) | 2007-02-12 | 2007-02-12 | A LCD-TV power under-voltage protection circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201041938Y true CN201041938Y (en) | 2008-03-26 |
Family
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNU200720118661XU Expired - Fee Related CN201041938Y (en) | 2007-02-12 | 2007-02-12 | A LCD-TV power under-voltage protection circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201041938Y (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101958527A (en) * | 2010-10-16 | 2011-01-26 | 深圳茂硕电源科技股份有限公司 | Boost type LED constant flow source under-voltage protection circuit |
| WO2018103574A1 (en) * | 2016-12-08 | 2018-06-14 | 深圳创维数字技术有限公司 | Over and under voltage protection circuit and set-top box |
| US11332592B2 (en) | 2017-09-27 | 2022-05-17 | Advansix Resins & Chemicals Llc | Method for preparing extruded polyamide foams |
-
2007
- 2007-02-12 CN CNU200720118661XU patent/CN201041938Y/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101958527A (en) * | 2010-10-16 | 2011-01-26 | 深圳茂硕电源科技股份有限公司 | Boost type LED constant flow source under-voltage protection circuit |
| WO2018103574A1 (en) * | 2016-12-08 | 2018-06-14 | 深圳创维数字技术有限公司 | Over and under voltage protection circuit and set-top box |
| US11332592B2 (en) | 2017-09-27 | 2022-05-17 | Advansix Resins & Chemicals Llc | Method for preparing extruded polyamide foams |
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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: 20080326 Termination date: 20150212 |
|
| EXPY | Termination of patent right or utility model |