CN102759654A - Low-voltage detection circuit - Google Patents
Low-voltage detection circuit Download PDFInfo
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- CN102759654A CN102759654A CN2011101079337A CN201110107933A CN102759654A CN 102759654 A CN102759654 A CN 102759654A CN 2011101079337 A CN2011101079337 A CN 2011101079337A CN 201110107933 A CN201110107933 A CN 201110107933A CN 102759654 A CN102759654 A CN 102759654A
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Abstract
The invention provides a low-voltage detection circuit, which comprises a Zener diode, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a first electronic switch, a second electronic switch and a controller, wherein the cathode of the Zener diode is connected with a power source through the first resistor and also directly connected with one terminal of the second resistor, and the anode of the Zener diode is grounded; the other terminal of the second resistor is grounded through the third resistor; a first terminal of the first electronic switch is connected with a node between the second resistor and the third resistor, a second terminal of the first electronic switch is grounded, and a third terminal of the first electronic switch is connected with the power source through the fourth resistor and also connected with a first terminal of the second electronic switch through the fifth resistor; and a second terminal of the second electronic switch is grounded, and a third terminal of the second electronic switch is connected with the power source through the sixth resistor and also directly connected with the controller. The low-voltage detection circuit can prompt whether the voltage of the power source is lower than a preset value or not through the controller, requires a low cost and occupies relatively small space.
Description
Technical field
The present invention relates to a kind of low-voltage circuit for detecting.
Background technology
The general low-voltage circuit for detecting that is designed on the market mostly adopts assembly such as comparer to design, and comparer one comes cost more expensive, and two take bigger space.
Summary of the invention
In view of above content, be necessary to provide the low-voltage circuit for detecting that a kind of cost is lower and take up room less.
A kind of low-voltage circuit for detecting is used to detect a power source voltage and whether is lower than a preset value, and this low-voltage circuit for detecting comprises a voltage stabilizing diode, first to the 6th resistance, one first electronic switch, one second electronic switch and a controller; The negative electrode of this voltage stabilizing diode links to each other with this power supply through first resistance; Also directly link to each other with an end of this second resistance, plus earth, the other end of this second resistance is through the 3rd resistance eutral grounding; First end of this first electronic switch links to each other with node between second resistance and the 3rd resistance; The second end ground connection, the 3rd end links to each other with power supply through the 4th resistance, also links to each other with first end of second electronic switch through the 5th resistance; The second end ground connection of this second electronic switch; The 3rd end links to each other with power supply through the 6th resistance, also directly links to each other with controller, and this controller judges according to the signal that it received whether this power source voltage is lower than preset value.
The above-mentioned low-voltage circuit for detecting characteristic through voltage stabilizing diode is earlier realized stablely when the power source voltage value is not less than preset value exporting preset value, will exporting its actual voltage value during less than preset value when the power source voltage value; Afterwards again through first resistance and second resistance to its dividing potential drop to open or to close first triode and second triode; Thereby realize when the power source voltage value be not less than preset value and during less than preset value controller will receive different level signals, be able to point out the user then.The component price that the present invention adopts is lower, and occupation space is less.
Description of drawings
Fig. 1 is the circuit diagram of the preferred embodiments of low-voltage circuit for detecting of the present invention.
The main element symbol description
| Power supply | VCC |
| Resistance | R1-R6 |
| Triode | Q1、Q2 |
| Voltage stabilizing diode | D1 |
| Diode | D2 |
| |
1 |
Following embodiment will combine above-mentioned accompanying drawing to further specify the present invention.
Embodiment
Below in conjunction with accompanying drawing and preferred embodiments the present invention is described in further detail:
Please refer to Fig. 1, whether the voltage that a low-voltage circuit for detecting is used to detect a power supply VCC is lower than a setting value.The preferred embodiments of this low-voltage circuit for detecting comprises a voltage stabilizing diode D1, a diode D2, triode Q1, Q2 and resistance R 1-R6.
The negative electrode of this voltage stabilizing diode D1 links to each other with power supply VCC through resistance R 1, and also the anode with diode D2 links to each other.The plus earth of this voltage stabilizing diode D1, the negative electrode of this diode D2 be in regular turn through resistance R 2 and R3 ground connection, and this resistance R 2 links to each other with the base stage of triode Q1 with node between the R3.The grounded emitter of this triode Q1, collector links to each other with power supply VCC through resistance R 4, also links to each other with the base stage of triode Q2 through resistance R 5.The grounded emitter of this triode Q2, collector links to each other with power supply VCC through resistance R 6, also is used to export signal to a controller (MCU) 1.
To the principle of low-voltage circuit for detecting of the present invention be described below:
This voltage stabilizing diode D1 is used for the voltage of power supply VCC output is carried out the voltage stabilizing processing; Characteristic according to voltage stabilizing diode; When its working current is higher than reference current (electric current when promptly making the voltage stabilizing diode operate as normal); This voltage stabilizing diode operate as normal, the voltage constant at its two ends are its burning voltage; When its working current is lower than reference current, this voltage stabilizing diode can not play the effect of voltage stabilizing.Therefore, the burning voltage of selected voltage stabilizing diode D1 and reference current parameter can make when power supply VCC during less than 3.3V this voltage stabilizing diode D1 do not work, when power supply VCC during more than or equal to 3.3V this voltage stabilizing diode D1 will stablize the magnitude of voltage of exporting 3.3V.
As power supply VCC during more than or equal to 3.3V, because the pressure stabilization function of voltage stabilizing diode D1, the magnitude of voltage of the negative electrode of this voltage stabilizing diode D1 is constant to be 3.3V.According to the characteristic of diode D2, the magnitude of voltage of this 3.3V is 2.6V through the magnitude of voltage after the diode D2.The magnitude of voltage of this 2.6V will make that through the dividing potential drop of resistance R 2 and R3 the magnitude of voltage at base stage place of triode Q1 is [2.6 * R3/ (R2+R3)] V again, and wherein R2 and R3 represent the resistance of resistance R 2 and R3 respectively.This moment, the resistance through setting resistance R 2 and R3 was so that [2.6 * R3/ (R2+R3)] equals 0.7, and promptly the magnitude of voltage at the base stage place of triode Q1 equals 0.7V.Characteristic according to triode can know, triode Q1 will be switched on this moment, makes the base stage of triode Q2 become low level then and ends.At this moment, the collector of this triode Q2 output high level promptly makes controller 1 receive the signal of high level.This controller 1 is not reported to the police to illustrate that this moment, the magnitude of voltage of this power supply VCC was not less than 3.3V.
As power supply VCC during less than 3.3V, this voltage stabilizing diode D1 will no longer play pressure stabilization function, promptly this moment voltage stabilizing diode D1 the magnitude of voltage of negative electrode will be less than 3.3V.According to top description, should will be through the magnitude of voltage after diode D2, resistance R 2 and the R3 less than 0.7V less than magnitude of voltage of 3.3V, promptly this moment triode Q1 the magnitude of voltage at base stage place less than 0.7V.At this moment, this triode Q1 ends, and makes the base stage of triode Q2 become high level and conducting then.The collector of this triode Q2 promptly makes this controller 1 receive low level signal the output low level signal.At this moment, this controller 1 will report to the police with prompting this moment this power supply VCC magnitude of voltage less than 3.3V.
The above-mentioned low-voltage circuit for detecting characteristic through voltage stabilizing diode D1 is earlier realized when the magnitude of voltage of power supply VCC the is not less than 3.3V stable 3.3V of output, will be exported its actual voltage value during less than 3.3V when the magnitude of voltage of power supply VCC; Afterwards again through resistance R 2 and R3 to its dividing potential drop to open or to close triode Q1 and Q2; Thereby realize when the magnitude of voltage of power supply VCC is not less than 3.3V controller 1 will receive high level signal, when the magnitude of voltage of power supply VCC during less than 3.3V controller 1 will receive low level signal, be able to point out the user then.
In addition, can know that this triode Q1 and Q2 all play the effect of electronic switch in circuit from foregoing description; Therefore; In other embodiment, this triode Q1 and Q2 also can adopt the transistor of other type to replace, even other electronic package with electronic switch function all can.Such as, when utilizing a FET to replace this triode Q1, the control signal of high level promptly makes this FET conducting, low level control signal promptly make this FET end, its principle of work is identical with triode.This electronic switch comprises one first end, one second end and one the 3rd end; This first end and resistance R 2 link to each other with node between the R3, the second end ground connection, and the 3rd end links to each other with power supply VCC through resistance R 4; Also pass through the first end ground connection of the resistance R 5 and second electronic switch; The second end ground connection of this second electronic switch, the 3rd end links to each other with power supply VCC through resistance R 6, also directly links to each other with controller 1.
Because the present invention adopts assemblies such as triode, resistance to realize the function of low-voltage detecting, for comparer, one comes price comparatively cheap, and two shared spaces are less.
Claims (4)
1. a low-voltage circuit for detecting is used to detect a power source voltage and whether is lower than a preset value, and this low-voltage circuit for detecting comprises a voltage stabilizing diode, first to the 6th resistance, one first electronic switch, one second electronic switch and a controller; The negative electrode of this voltage stabilizing diode links to each other with this power supply through first resistance; Also directly link to each other with an end of this second resistance, plus earth, the other end of this second resistance is through the 3rd resistance eutral grounding; First end of this first electronic switch links to each other with node between second resistance and the 3rd resistance; The second end ground connection, the 3rd end links to each other with power supply through the 4th resistance, also links to each other with first end of second electronic switch through the 5th resistance; The second end ground connection of this second electronic switch; The 3rd end links to each other with power supply through the 6th resistance, also directly links to each other with controller, and this controller judges according to the signal that it received whether this power source voltage is lower than preset value.
2. low-voltage circuit for detecting as claimed in claim 1 is characterized in that: this first electronic switch is a triode, and the base stage of this triode, emitter and collector be first end, second end and the 3rd end of corresponding first electronic switch respectively.
3. low-voltage circuit for detecting as claimed in claim 1 is characterized in that: this second electronic switch is a triode, and the base stage of this triode, emitter and collector be first end, second end and the 3rd end of corresponding second electronic switch respectively.
4. low-voltage circuit for detecting as claimed in claim 1; It is characterized in that: said low-voltage circuit for detecting also comprises a diode; This diode is connected between the negative electrode of this second resistance and voltage stabilizing diode; The anode of this diode links to each other with the negative electrode of voltage stabilizing diode, and the negative electrode of this diode links to each other with this second resistance.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011101079337A CN102759654A (en) | 2011-04-28 | 2011-04-28 | Low-voltage detection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011101079337A CN102759654A (en) | 2011-04-28 | 2011-04-28 | Low-voltage detection circuit |
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| Publication Number | Publication Date |
|---|---|
| CN102759654A true CN102759654A (en) | 2012-10-31 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011101079337A Pending CN102759654A (en) | 2011-04-28 | 2011-04-28 | Low-voltage detection circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104184112A (en) * | 2013-05-27 | 2014-12-03 | 深圳市海洋王照明工程有限公司 | Input under-voltage detection circuit |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5811809A (en) * | 1995-07-17 | 1998-09-22 | British Aerospace Public Limited Company | Nuclear event detector and threshold detector circuit therefor |
| EP1750137A2 (en) * | 2001-07-20 | 2007-02-07 | Power Integrations, Inc. | Method and apparatus for low cost current and voltage sensing in circuits as a function of a voltage drop |
| CN201138355Y (en) * | 2007-11-15 | 2008-10-22 | 高子泉 | Wide-region high-voltage circuit indicating equipment |
| ES2319951A1 (en) * | 2008-01-17 | 2009-05-14 | Francisco Monagas Yanez | Device to locate and mark electrical cables without tension. (Machine-translation by Google Translate, not legally binding) |
| US20100244885A1 (en) * | 2009-03-24 | 2010-09-30 | Kyoungmin Lee | Under-voltage and over-voltage detection circuit and driving method thereof |
| CN101887621A (en) * | 2010-06-04 | 2010-11-17 | 魏锡秦 | Monitoring protector of electrical fire |
| CN101988934A (en) * | 2009-07-30 | 2011-03-23 | 鸿富锦精密工业（深圳）有限公司 | Undervoltage detection and alarm circuit |
-
2011
- 2011-04-28 CN CN2011101079337A patent/CN102759654A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5811809A (en) * | 1995-07-17 | 1998-09-22 | British Aerospace Public Limited Company | Nuclear event detector and threshold detector circuit therefor |
| EP1750137A2 (en) * | 2001-07-20 | 2007-02-07 | Power Integrations, Inc. | Method and apparatus for low cost current and voltage sensing in circuits as a function of a voltage drop |
| CN201138355Y (en) * | 2007-11-15 | 2008-10-22 | 高子泉 | Wide-region high-voltage circuit indicating equipment |
| ES2319951A1 (en) * | 2008-01-17 | 2009-05-14 | Francisco Monagas Yanez | Device to locate and mark electrical cables without tension. (Machine-translation by Google Translate, not legally binding) |
| US20100244885A1 (en) * | 2009-03-24 | 2010-09-30 | Kyoungmin Lee | Under-voltage and over-voltage detection circuit and driving method thereof |
| CN101988934A (en) * | 2009-07-30 | 2011-03-23 | 鸿富锦精密工业（深圳）有限公司 | Undervoltage detection and alarm circuit |
| CN101887621A (en) * | 2010-06-04 | 2010-11-17 | 魏锡秦 | Monitoring protector of electrical fire |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104184112A (en) * | 2013-05-27 | 2014-12-03 | 深圳市海洋王照明工程有限公司 | Input under-voltage detection circuit |
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| PB01 | Publication | ||
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Application publication date: 20121031 |