CN101113992B - Fan testing circuit - Google Patents
Fan testing circuit Download PDFInfo
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- CN101113992B CN101113992B CN200710129854XA CN200710129854A CN101113992B CN 101113992 B CN101113992 B CN 101113992B CN 200710129854X A CN200710129854X A CN 200710129854XA CN 200710129854 A CN200710129854 A CN 200710129854A CN 101113992 B CN101113992 B CN 101113992B
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- 238000001514 detection method Methods 0.000 abstract description 8
- 230000015556 catabolic process Effects 0.000 description 3
- 238000004891 communication Methods 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- 238000002955 isolation Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
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Abstract
A fan detection circuit comprises an overcurrent protection device, the two ends of the overcurrent protection device are respectively connected with a fan power supply and a first end of a fan interface, the invention is characterized in that the invention also comprises a clamp circuit and a sub-voltage circuit which are connected between a second end of the fan interface and the ground, and an electronic switch device, the control end is connected with an intermediate tap of the sub-voltage circuit, when the fan interface is connected or disconnected, the output voltage of the intermediate tap of the sub-voltage circuit controls the electronic switch device to output different digital signal value. The invention adopts the simplest discrete devices and achieves the basic fan state detection function, the reliability is high, and the cost is low.
Description
Technical field
The present invention relates to the fan testing circuit in the communication facilities.
Background technology
Some communication facilitiess are bigger because of power consumption, often need wind-cooling heat dissipating, therefore can use fan.Because of the cost relation, fan generally has only fan power supply and ground wiring on the low side communication facilities, for this fan state monitoring, can only realize by monitoring fan power supply electric current.
Existing fan-status detection technique is more, can pass through the realization of detection fan electromotor state, if fan only provides power supply and ground to go between, then most detection source current that passes through is realized, can pass through ADC or the comparer realization detection to power supply status.
Summary of the invention
The technical problem to be solved in the present invention is that the fan testing circuit of a kind of high reliability, Ultra Low Cost is provided.
For addressing the above problem; the present invention proposes a kind of fan testing circuit; comprise the over-current protection device that two ends link to each other with fan interface first end with fan power supply respectively; it is characterized in that; also comprise the clamping circuit and the bleeder circuit that are connected between fan interface second end and the ground; and control end is connected to an electronic switching device of described bleeder circuit intermediate contact; when described fan interface connection or disconnection, the output voltage of described bleeder circuit intermediate contact is controlled the different digital signal value of described electronic switching device output.
Further, foregoing circuit also can have following characteristics, also comprises a filter capacitor C1, and this capacitor C 1 is connected between described over-current protection device and the end and ground that described fan interface links to each other.
Further, foregoing circuit also can have following characteristics, described clamping circuit comprises a diode or a plurality of diodes of connecting mutually, and the plus earth of last diode, when described fan interface is communicated with, clamp voltage during described diode forward conducting is higher than the cut-in voltage of described electronic switching device through described bleeder circuit dividing potential drop at the magnitude of voltage of described intermediate contact.
Further, foregoing circuit also can have following characteristics, described bleeder circuit comprises the resistance of a plurality of series connection, when described fan interface is communicated with, the clamp voltage of described clamping circuit is higher than the cut-in voltage of described electronic switching device at the magnitude of voltage of described intermediate contact behind described a plurality of electric resistance partial pressures.
Further; foregoing circuit also can have following characteristics; also comprise two ferrite beans; directly link to each other with second end with first end of described fan interface respectively; wherein the other end of the ferrite bean that links to each other with described fan interface first end is connected to described over-current protection device, and the other end of the ferrite bean that links to each other with described fan interface second end is connected to described clamping circuit and bleeder circuit.
Further, foregoing circuit also can have following characteristics, and described electronic switching device is double pole triode or Metal-Oxide Semiconductor field effect transistor.
Further, foregoing circuit also can have following characteristics, described electronic switching device is a double pole triode, its base stage is connected to the intermediate contact of described bleeder circuit, its collector links to each other with second source VCC2 through a resistance R 4, its grounded emitter, the digital signal of output is drawn from the collector of this triode.
Further, foregoing circuit also can have following characteristics, also comprises voltage stabilizing diode D3, and this voltage stabilizing diode D3 is connected between the control end and ground of described electronic switching device.
Further, foregoing circuit also can have following characteristics, also comprises a capacitor C 2, and this capacitor C 2 is connected between the control end and ground of described electronic switching device, is used for the described control end voltage noise of filtering.
Further, foregoing circuit also can have following characteristics, and the span of described capacitor C 2 is 1uF～0.01uF.
As can be seen, the present invention is by realizing the detection to fan-status to the detection of fan power supply electric current; Clamp voltage when utilizing the forward conduction of diode judges whether whether fan is on the throne, have short circuit or short trouble; Utilize the opening feature of double pole triode or MOSFET (metal-oxide field effect transistor), the fan work state is converted into digital quantity, use for system monitoring.In addition, consider the reliability and the safety of system, consider demands such as fan short-circuit protection, overcurrent protection, noise isolation in the design.Therefore, the present invention adopts the simplest discrete device, has realized basic fan-status measuring ability, the reliability height, and cost is low.
Description of drawings
Fig. 1 is a fan testing circuit schematic diagram of the present invention.
Embodiment
Below in conjunction with accompanying drawing and application example technical scheme of the present invention is described in detail.
Shown in Figure 1 is the fan testing circuit of present embodiment, below the device in the circuit is done simple declaration:
F1 is a fuse, is used for the protection of overcurrent safety;
C1 is a filter capacitor, is used for power filter;
L1 and L2 are ferrite bean, and the electrical noise when being used to isolate fan work prevents that noise is coupled to internal system by approach such as power supply and ground wires, EVAC (Evacuation Network Computer Model) work;
D1 and D2 are diode, constitute a clamping circuit, the peak point current the when forward current of diode must be greater than fan work, the about 0.7V of clamp voltage; In our application, the diode maximum forward working current of employing is 1A, and in the fan normal range of operation, the diode-clamped voltage of measuring is about 760mV, D1, the about 1.5V of clamp voltage of D2 series connection;
T1 is a double pole triode, but also can adopt other electronic switching device such as MOSFET.
R1 when the clamp voltage of D1 can reliably be opened triode T1, welds R1 for the 0ohm resistance of choosing weldering, and whether the clamp voltage of D1 can reliably open triode T1, depends on the parameter of D1 and T1; When D1 can not reliably open V1, do not weld R1, this moment, the cut-in voltage sum of D1 and D2 can reliably be opened T1; In the present embodiment, R1 does not weld, and is that D1 and D2 all have pressure drop yet.
C2 is an electric capacity, 1uF～0.01uF can, be used for the noise of filtering T1 base voltage, reduce the erroneous judgement probability;
R2 and R3 constitute bleeder circuit, guarantee transistor base opening and closing reliably under the different conditions of fan; R2=536ohm in our application, R3=1kohm, the cut-in voltage of R2 and R3 and T1 and D1 in the different application, the forward voltage drop of D2 is relevant, and resistance is chosen can be different.
D3 is a voltage stabilizing diode, and breakdown reverse voltage must not be higher than the ceiling voltage that triode T1 base stage can be tolerated, when being used for the short circuit of fan connector to the protection of triode.
In our application, fan power supply VCC1 is 12V, and digital display circuit power supply VCC2 is 3.3V.
Annexation to above device describes below, can refer to " the linking to each other " in it should be noted that in instructions and the claim directly link to each other, and also can refer to link to each other at interval.As shown in Figure 1, diode D1 and D2 series connection, the D2 plus earth, resistance R 1 (optional) is connected between the contact and ground of D1 and D2.The D1 anode links to each other with second end of fan interface through ferrite bean L2, and first end of fan interface links to each other with fan power supply VCC1 through oxysome magnetic bead L1, fuse F1 successively, and filter capacitor C1 is connected between the contact and ground of F1 and L1; Resistance R 2, R3 are connected between D1 anode and the ground, its intermediate contact links to each other with triode T1 base stage, the T1 collector links to each other with second source VCC2 through resistance R 4, its grounded emitter, capacitor C 2 and voltage stabilizing diode D3 are connected in parallel between T1 base stage and the ground, and the digital signal FAN_OK of output draws from the T1 collector.
The circuit working principle:
Referring to Fig. 1, when fan was on the throne and working properly, electric current can be via F1, L1, and L2, D1, D2 flow to ground, and the R2 branch road can be ignored because shunting is less.If the fan power consumption is about 1W, then the electric current on D1 and the D2 about 100mA, the about 1.5V of forward voltage drop Vd1+Vd2, because of the special volt-ampere characteristic of diode, this voltage is more stable, it is less influenced by the fan current fluctuation.
Because of D1, the D2 forward conduction, this moment T1 base voltage Vb ≈ (Vd1+Vd2) * R3/ (R2+R3), according to Vd1+Vd2=1.5V, R3=1kohm, R2=536ohm, calculate Vb ≈ 0.97V, press Vbe-sat 0.85V, can guarantee that switch triode T1 is fully saturated greater than the saturated basic radio of selected triode T1 (model PMBT3904), collector-emitter voltage when T1 is saturated is about Vce=0.3V, collector current Ic=(Vcc2-Vce)/R4=0.3mA, R4=10kohm, Vcc2=3.3V, the T1 dissipated power is approximately Vce*Ic=0.1mW, much smaller than triode maximum diffipation power 250mW.
The not on the throne or inner breaking-up of fan of fan causes opens circuit, not under the situation of current sinking, the T1 base potential is 0 (this moment, the T1 base stage was in high-impedance state), be operated in cut-off state, this moment, FAN_OK was equivalent to directly by moving Vcc2 on the R4 to, do not consider that under the situation of FAN_OK fan-out load current, the FAN_OK level is about Vcc2.
In addition, the failure condition of fan short circuit has been considered in the design of circuit, can guarantee that fan damages the global failure that does not cause the circuit except that supervisory system.Protective tube F1 can fuse under the situation of fan overcurrent, guarantees the fault isolation of power unit; If protective tube is fusing not; then D3 can play the protective effect to late-class circuit; D3 is a voltage stabilizing diode; the voltage stabilizing value must be lower than base stage-emitter-base bandgap grading Maximum tolerance voltage of triode T1; protection triode T1; prevent that T1 from because of the too high breakdown back 12V of base voltage the situation direct and conducting of FAN_OK network occurs, realizing the fault isolation of signal section.D3 Zener breakdown voltage stabilizing 2.4V in our design, T1 base stage Maximum tolerance voltage is 6V.
Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection domain of the appended claim of the present invention.
Claims (9)
1. fan testing circuit, comprise the over-current protection device that two ends link to each other with fan interface first end with fan power supply respectively, it is characterized in that, also comprise the clamping circuit and the bleeder circuit that all are connected between fan interface second end and the ground, and control end is connected to an electronic switching device of described bleeder circuit intermediate contact, and described electronic switching device is double pole triode or Metal-Oxide Semiconductor field effect transistor; Wherein, described clamping circuit comprises a diode or a plurality of diodes of connecting mutually, and the plus earth of last diode; Described bleeder circuit comprises the resistance of a plurality of series connection; When described fan interface connection or disconnection, the output voltage of described bleeder circuit intermediate contact is controlled the different digital signal value of described electronic switching device output.
2. fan testing circuit as claimed in claim 1 is characterized in that:
Also comprise a filter capacitor C1, this capacitor C 1 is connected between described over-current protection device and the end and ground that described fan interface links to each other.
3. fan testing circuit as claimed in claim 1 is characterized in that:
When described fan interface was communicated with, the clamp voltage during described diode forward conducting was higher than the cut-in voltage of described electronic switching device through described bleeder circuit dividing potential drop at the magnitude of voltage of described intermediate contact.
4. as claim 1 or 3 described fan testing circuits, it is characterized in that:
When described fan interface was communicated with, the clamp voltage of described clamping circuit was higher than the cut-in voltage of described electronic switching device at the magnitude of voltage of described intermediate contact behind described a plurality of electric resistance partial pressures.
5. fan testing circuit as claimed in claim 1 is characterized in that:
Also comprise two ferrite beans; directly link to each other with second end with first end of described fan interface respectively; wherein the other end of the ferrite bean that links to each other with described fan interface first end is connected to described over-current protection device, and the other end of the ferrite bean that links to each other with described fan interface second end is connected to described clamping circuit and bleeder circuit.
6. fan testing circuit as claimed in claim 1 is characterized in that:
The base stage of described double pole triode is connected to the intermediate contact of described bleeder circuit, the collector of described double pole triode links to each other with second source VCC2 through a resistance R 4, the grounded emitter of described double pole triode, the digital signal of output is drawn from the collector of described double pole triode.
7. fan testing circuit as claimed in claim 1 is characterized in that:
Also comprise voltage stabilizing diode D3, this voltage stabilizing diode D3 is connected between the control end and ground of described electronic switching device.
8. as claim 1,2 or 7 described fan testing circuits, it is characterized in that:
Also comprise a capacitor C 2, this capacitor C 2 is connected between the control end and ground of described electronic switching device, is used for the described control end voltage noise of filtering.
9. fan testing circuit as claimed in claim 8 is characterized in that:
The span of described capacitor C 2 is 1uF～0.01uF.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200710129854XA CN101113992B (en) | 2007-07-27 | 2007-07-27 | Fan testing circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200710129854XA CN101113992B (en) | 2007-07-27 | 2007-07-27 | Fan testing circuit |
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| Publication Number | Publication Date |
|---|---|
| CN101113992A CN101113992A (en) | 2008-01-30 |
| CN101113992B true CN101113992B (en) | 2010-06-02 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200710129854XA Expired - Fee Related CN101113992B (en) | 2007-07-27 | 2007-07-27 | Fan testing circuit |
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| CN (1) | CN101113992B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110763994A (en) * | 2019-12-04 | 2020-02-07 | 新阳荣乐(上海)汽车电子有限公司 | Automobile switch detection working circuit structure |
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- 2007-07-27 CN CN200710129854XA patent/CN101113992B/en not_active Expired - Fee Related
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| CN101113992A (en) | 2008-01-30 |
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Owner name: STATE GRID ZHEJIANG ELECTRIC POWER COMPANY SHAOXIN Effective date: 20150105 Owner name: STATE GRID CORPORATION OF CHINA Free format text: FORMER OWNER: ZTE CORPORATION Effective date: 20150105 |
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| CB03 | Change of inventor or designer information |
Inventor after: Lv Peisong Inventor after: Zheng Ye Inventor after: Huang Jianyang Inventor after: Jiang Biao Inventor after: Lv Xinyi Inventor after: Zhao Chunlin Inventor after: Huang Jiefu Inventor after: Wang Yuefeng Inventor after: Li Xinshuang Inventor before: Li Xinshuang |
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| COR | Change of bibliographic data |
Free format text: CORRECT: INVENTOR; FROM: LI XINSHUANG TO: LV PEISONG ZHENG YE HUANG JIANYANG JIANG BIAO LV XINYI ZHAO CHUNLIN HUANG JIEFU WANG YUEFENG LI XINSHUANG Free format text: CORRECT: ADDRESS; FROM: 518057 SHENZHEN, GUANGDONG PROVINCE TO: 100031 XICHENG, BEIJING |
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| TR01 | Transfer of patent right |
Effective date of registration: 20150105 Address after: 100031 Xicheng District West Chang'an Avenue, No. 86, Beijing Patentee after: State Grid Corporation of China Patentee after: State Grid Zhejiang Electric Power Company Patentee after: Shaoxing Power Supply Company of State Grid Zhejiang Electric Power Company Patentee after: State Grid Zhejiang Zhuji Power Supply Co., Ltd. Patentee after: Zhuji Dongbai Electric Power Equipment Manufacturing Co., Ltd. Address before: 518057 Nanshan District high tech Industrial Park, Guangdong, South Road, science and technology, ZTE building, legal department Patentee before: ZTE Corporation |
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| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100602 Termination date: 20170727 |
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| CF01 | Termination of patent right due to non-payment of annual fee |