CN204302356U - A kind of circuit structure of negtive voltage detection device and negtive voltage detection device - Google Patents
A kind of circuit structure of negtive voltage detection device and negtive voltage detection device Download PDFInfo
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- CN204302356U CN204302356U CN201420838911.7U CN201420838911U CN204302356U CN 204302356 U CN204302356 U CN 204302356U CN 201420838911 U CN201420838911 U CN 201420838911U CN 204302356 U CN204302356 U CN 204302356U
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Abstract
The utility model discloses a kind of circuit structure and negtive voltage detection device of negtive voltage detection device, be provided with gating circuit, RC circuit and timer; Described gating circuit is corresponding with a reference voltage and negative voltage to be detected respectively to be connected, and selects wherein a road voltage and described RC circuit communication; Described RC circuit according to the charging and discharging state triggered timer of its electric capacity, by the discharge and recharge time of electric capacity described in timer record.The magnitude of voltage of negative voltage is quantified as time value by negtive voltage detection device of the present utility model, utilize described time value and by the quantization time value corresponding to known reference voltage, technical staff just instead can release the magnitude of voltage of described negative voltage, not only can improve the accuracy of negtive voltage detection thus, and circuit structure is simple, with low cost, power consumption is little, can be widely applied to all needs to carry out in the circuit design of negtive voltage detection.
Description
Technical field
The utility model belongs to voltage detecting technical field, specifically, relates to the circuit structure design in a kind of checkout gear for measuring negative voltage and described checkout gear.
Background technology
In electronic engineering design field, often can use negative voltage, such as current a lot of LCD displays utilize negative voltage driving.In order to ensure the Electrical Safety of electronic device using negative voltage to power or drive, needing to detect the size of these negative voltages, if directly adopt single-chip microcomputer to quantize the value of negative voltage, is then a very difficult thing.Therefore, the existing testing circuit for negative voltage design mostly adopts and negative voltage transition is become positive voltage, after then utilizing bleeder circuit to carry out decompression transformation to the positive voltage after conversion, transfers to analog-digital converter to calculate the value of negative voltage.This traditional negtive voltage detection mode, circuit structure is complicated, and accuracy of detection is not high, carries out dividing potential drop and sampling, therefore can cause the obvious lifting of system power dissipation, be not suitable for applying in the electronic product that some horsepower requirements is higher owing to needing to introduce resistance in circuit.
Summary of the invention
The purpose of this utility model is the circuit structure providing a kind of negtive voltage detection device, magnitude of voltage to be detected can be quantified as time value, thus the magnitude of voltage carried out for technical staff is follow-up calculating provides an intermediate parameters.
For solving the problems of the technologies described above, the utility model is achieved by the following technical solutions:
A circuit structure for negtive voltage detection device, is provided with gating circuit, RC circuit and timer; Described gating circuit is corresponding with a reference voltage and negative voltage to be detected respectively to be connected, and selects wherein a road voltage and described RC circuit communication; Described RC circuit according to the charging and discharging state triggered timer of its electric capacity, by the discharge and recharge time of electric capacity described in timer record.
In the moment going out described capacitor discharge to enable system automatic decision and terminate, described RC circuit design is preferably become RC integrating circuit by the utility model, comprises operational amplifier, resistance and described electric capacity; The in-phase input end ground connection of described operational amplifier, after inverting input and described resistant series, is connected to described gating circuit, for being communicated with described negative voltage or reference voltage; Between the inverting input that described electric capacity is connected to described operational amplifier and output; Utilize the timer described in state change triggers of described operational amplifier output level.
Further, the power end of described operational amplifier connects a dc source, earth terminal connected system ground.
Preferably, a comparator is also provided with in described RC integrating circuit, the inverting input of described comparator connects the output of described operational amplifier, the in-phase input end ground connection of comparator, the timer described in low and high level change triggers utilizing comparator to export.
Further, the power end of described comparator connects dc source, earth terminal connected system ground.
Preferably, described timer is preferably integrated in a processor; The interrupt interface of the output connection handling device of described comparator, when the level exported by described comparator is high level by low transition, Trigger processor enters interruption, controls timer and stops timing, the discharge time of record electric capacity.Because processor responds the speed of interruption quickly, only need several machine cycle, therefore can improve degree of accuracy during timer.
As a kind of preferred structure design of described gating circuit, the utility model is provided with two switching tubes in described gating circuit, the control pole receiving path switching signal of two switching tubes, the switch ways of two switching tubes is connected between described negative voltage and RC circuit or is connected between described reference voltage and RC circuit, realizes switching the gating of described negative voltage and reference voltage.
Preferably, described switching tube preferably adopts N-channel MOS pipe, and the grid receiving path switching signal respectively of two N-channel MOS pipes, drain electrode connects one to one with described reference voltage and negative voltage to be detected respectively, the RC circuit described in source electrode connects.
Based on foregoing circuit structural design, the utility model additionally provides a kind of negtive voltage detection device adopting described circuit structure design, is provided with gating circuit, RC circuit and timer; Described gating circuit is corresponding with a reference voltage and negative voltage to be detected respectively to be connected, and selects wherein a road voltage and described RC circuit communication; Described RC circuit according to the charging and discharging state triggered timer of its electric capacity, by the discharge and recharge time of electric capacity described in timer record.
Compared with prior art, advantage of the present utility model and good effect are: the magnitude of voltage of negative voltage is quantified as time value by negtive voltage detection device of the present utility model, utilize described time value and by the quantization time value corresponding to known reference voltage, technical staff just instead can release the magnitude of voltage of described negative voltage, not only can improve the accuracy of negtive voltage detection thus, and circuit structure is simple, with low cost, power consumption is little, can be widely applied to all needs to carry out in the circuit design of negtive voltage detection.
After reading the detailed description of the utility model embodiment by reference to the accompanying drawings, other features of the present utility model and advantage will become clearly.
Accompanying drawing explanation
Fig. 1 is the schematic block circuit diagram of a kind of embodiment of the negtive voltage detection device that the utility model proposes;
Fig. 2 is the schematic block circuit diagram of another embodiment of the negtive voltage detection device that the utility model proposes;
Fig. 3 is the circuit theory diagrams of a specific embodiment shown in Fig. 2 corresponding to schematic block circuit diagram.
Detailed description of the invention
Below in conjunction with accompanying drawing, detailed description of the invention of the present utility model is described in more detail.
The present embodiment, in order to simplify the design of negtive voltage detection device, proposes a kind of design philosophy magnitude of voltage being quantified as time value, according to the anti-magnitude of voltage released corresponding to this time value of the difference of time value.Specifically, can first by known amplitude V
rEFreference voltage be quantified as time value T1, then by negative voltage V to be detected
ialso be quantified as time value T2, and then utilize the corresponding relation of magnitude of voltage and time value: V
rEF/ T1=-V
i/ T2, instead can release the value V of described negative voltage to be detected
i=-V
rEF* T2/T1.
In order to magnitude of voltage is quantified as time value, the present embodiment adopts and realizes the patten's design of capacitor charge and discharge.Specifically, a road amplitude V can first be selected
rEFthe reference voltage of known positive polarity to the charging of RC circuit, and detects the charging interval T1 in described RC circuit needed for electric capacity C.In the present embodiment, consider that the charging voltage on electric capacity C arrives V never
rEF, just the charging interval is longer, and the voltage on electric capacity C is more close to V
rEF.In order to ensure the validity of result of calculation, the voltage that the present embodiment definition is worked as on electric capacity C reaches 90%*V
rEFtime above, just think that electric capacity C is full of electricity.In order to improve follow-up negative voltage V further
ithe accuracy calculated, electric capacity C preferably charges and arrives 99%*V by the present embodiment
rEFthe charging interval of Shi Suoyong is designated as T1.Obtain parameter V
rEFafter T1, utilize negative voltage V to be detected
ielectric capacity C in described RC circuit is charged again, terminates until electric capacity C charges.In the present embodiment, in order to ensure that the voltage on electric capacity C can as best one can close to the value V of negative voltage to be detected
i, the time of charging to described electric capacity C can be set as far as possible long, at least charging interval Tc>2RC should be set, such as, be set to 2.5RC, 3RC or longer time, to ensure that electric capacity C can be full of electricity.After electric capacity C charging terminates, the negative voltage V described in cut-out
i, control described electric capacity C and discharge, and record T2 discharge time of described electric capacity C.Described discharge time T2 and electric capacity C from the electric charge discharged on electric capacity C be 0 time required time.Then by acquired parameter V
rEF, T1 and T2 substitute into formula: V
i=-V
rEF* T2/T1, can calculate the value V of described negative voltage to be detected
i.Thus, the detection to negative voltage is just achieved.
Based on above-mentioned negtive voltage detection method, the present embodiment proposes a kind of negtive voltage detection device, to realize the automatic measurement to negative voltage to be detected.
Shown in Figure 1, the negtive voltage detection device of the present embodiment is mainly provided with the parts such as gating circuit, RC circuit and timer.Wherein, described gating circuit is used at negative voltage V to be detected
iwith the reference voltage V of positive polarity
rEFbetween carry out gating switching, its two-way gating end respectively with described negative voltage V
iwith reference voltage V
rEFcorresponding connection, common port connects RC circuit, and control end is used for receive path switching signal, and the selection utilizing described switching signal to realize between two paths switches.In the present embodiment, described switching signal can be exported by processor provides.To negative voltage V to be detected
iwhen starting to measure, first processor output switching signal controls gating circuit by negative voltage V to be detected
iwith RC circuit communication, utilize negative voltage V to be detected
ielectric capacity C in RC circuit is charged.Meanwhile, processor starts timer and starts timing, when timer spill-over goes out or timing time arrives setting value Tc, outputs signal to processor.Described processor, after the signal receiving timer feedback, just can judge that described electric capacity C charges and terminate.In order to ensure that electric capacity C can be full of electricity, the present embodiment arranges the time that described timer spill-over goes out and is greater than 2RC, or described setting value Tc>2RC is set, preferably arranging the described charging interval can reach 3RC or 4RC, to ensure that the charging voltage on electric capacity C equals described negative voltage V substantially
i.
After processor detects that electric capacity C charging terminates, output switching signal (switching signal here also directly can be exported by timer and provide), to gating circuit, controls gating circuit and switches to reference voltage V
rEFwith described RC circuit communication, discharge to control described electric capacity C.Meanwhile, start timer and reset and restart timing, when the electric charge on electric capacity C is reduced to 0, electric capacity C discharge end, and processor control timer stopping timing, records T2 discharge time of described electric capacity C.
Then, processor is according to the T2 and the amplitude V of reference voltage that preserves in advance discharge time received
rEFwith utilize described reference voltage V
rEFfor charging interval T1 required when described electric capacity C charges, utilize formula: V
i=-V
rEF* T2/T1, can calculate described negative voltage V
isize.Conveniently testing staff checks, can design display screen further, the processor described in connection, with display measurement result.
Conveniently processor judges when electric capacity C discharges end, and described RC circuit design is preferably become the form of RC integrating circuit by the present embodiment, and shown in Figure 2, described timer can be integrated in processor MCU, to simplify circuit design further.
Fig. 3 is a kind of preferred circuit assembling structure of described RC integrating circuit and gating circuit, wherein, can design two switching tubes Q1, Q2, be described for N-channel MOS pipe in described gating circuit.The grid of two N-channel MOS pipes Q1, Q2 is connected one to one with the two-way GPIO mouth of processor MCU respectively, two-way switching signal MCU_SWITCH1, MCU_SWITCH2 that receiving processor MCU exports, to stagger the time conducting to control two N-channel MOS pipes Q1, Q2.The drain electrode of metal-oxide-semiconductor Q1 is connected reference voltage V
rEF, source electrode connects the resistance R in RC integrating circuit; The drain electrode of metal-oxide-semiconductor Q2 is connected negative voltage V to be detected
i, source electrode is also connected to the resistance R in RC integrating circuit.Operational amplifier U138, comparator U155 and described resistance R, electric capacity C is provided with in described RC integrating circuit.By the in-phase input end+ground connection of described operational amplifier U138, inverting input-be connected to described gating circuit by the resistance R of series connection, switches by gating circuit the negative voltage V connected for connecting
ior reference voltage V
rEF.Between the inverting input-that described electric capacity C is connected to operational amplifier U138 and output, the power end of operational amplifier U138 connects dc source VDD, earth terminal connected system ground.By the output of the inverting input of described comparator U155-be connected to operational amplifier U138, in-phase input end+the ground connection of comparator U155, the dc source VDD described in power end connection of comparator U155, earth terminal connected system ground, by the output connection handling device MCU of comparator U155, the height state of the level that processor MCU exports according to comparator U155, can judge whether electric capacity C discharges end exactly.
In the present embodiment, change to enable the processor MCU low and high level that response comparator U155 exports fast, preferably the output of comparator U155 is connected to a road interrupt interface MCU_INTERRUPT of processor MCU, the mode adopting control processor MCU to enter interruption enters follow-up handling procedure rapidly to make processor.
Below the operation principle of the negative voltage detection circuit shown in Fig. 3 is specifically addressed.
First, by negative voltage V to be detected
ibe connected to the drain electrode of metal-oxide-semiconductor Q2, start-up circuit brings into operation.Switching signal MCU_SWITCH1 is set to low level by processor MCU, MCU_SWITCH2 is set to high level, and then control metal-oxide-semiconductor Q1 cut-off, metal-oxide-semiconductor Q2 opens.Now, negative voltage V to be detected
iconnect with RC integrating circuit, described negative voltage V
icharged to electric capacity C by resistance R, make electric capacity C concatenation operation amplifier U138 inverting input-side be negative pole, the side of concatenation operation amplifier U138 output is positive pole.Now, operational amplifier U138 exports positive voltage, and via comparator U155 output low level, and then control processor MCU enters interrupt routine.Processor MCU is had no progeny in entering, and starts timer and starts timing, when timer full gate begins to overflow (or timing time arrive in setting value Tc>2RC), shows that the voltage on now electric capacity C has reached negative voltage V
ivalue.Now, switching signal MCU_SWITCH1 is set to high level by processor MCU, MCU_SWITCH2 is set to low level, and then control metal-oxide-semiconductor Q1 saturation conduction, metal-oxide-semiconductor Q2 ends, thus cuts off negative voltage V
iwith the connection of RC integrating circuit, transfer reference voltage V to
rEFbe communicated with described RC integrating circuit.When processor MCU exports high level effective switching signal MCU_SWITCH1 control metal-oxide-semiconductor Q1 saturation conduction, start described timer simultaneously and reset and restart timing.Owing to being linked into the reference voltage V of RC integrating circuit
rEFfor positive voltage, therefore electric capacity C starts electric discharge by resistance R, and the electronics on it starts to reference voltage V
rEFflowing.At the end of electric capacity C discharges, the voltage on electric capacity C is zero, reference voltage V
rEFstart to charge to electric capacity C, make electric capacity C concatenation operation amplifier U138 inverting input-side be positive pole, the side of concatenation operation amplifier U138 output is negative pole.Now, operational amplifier U138 exports negative voltage, exports high level via comparator U155.When processor MCU detects that the voltage exported by comparator U155 is high level, judge that electric capacity C electric discharge terminates, control timer and stop timing, and using the discharge time of the timing time of timer record as electric capacity C, be designated as T2.Suppose to utilize reference voltage V
rEFby resistance R for electric capacity C charge needed for charging interval be T1, so according to computing formula: V
i=-V
rEF* T2/T1, can calculate negative voltage V to be detected
ivalue.
Certainly, for the processor that can detect generating positive and negative voltage change, comparator U155 can be omitted, directly the output of operational amplifier U138 is connected to described processor, when processor detects that the voltage exported by operational amplifier U138 is reversed to negative voltage by positive voltage, can judge that electric capacity C discharges and terminate.
Certainly, in the present embodiment, described gating circuit also can adopt the design of other switching tubes such as triode, controllable silicon to realize, only need by the control pole connection handling device MCU of two switching tubes, the switching signal that receiving processor exports, the switch ways of two switching tubes is connected to described negative voltage V
iand between RC circuit or be connected to described reference voltage V
rEFand between RC circuit, can realize described negative voltage V
iwith reference voltage V
rEFgating switch.The concrete assembling structure of the present embodiment to described gating circuit is not limited in above citing.
The negtive voltage detection device of the present embodiment, certainty of measurement is high, easy to use, with low cost, power consumption is little, and being adapted at allly needs to carry out to apply in the electronic product of negtive voltage detection.
Certainly; above-mentioned explanation is not to restriction of the present utility model; the utility model is also not limited in above-mentioned citing, the change that those skilled in the art make in essential scope of the present utility model, remodeling, interpolation or replacement, also should belong to protection domain of the present utility model.
Claims (9)
1. a circuit structure for negtive voltage detection device, is characterized in that: be provided with gating circuit, RC circuit and timer; Described gating circuit is corresponding with a reference voltage and negative voltage to be detected respectively to be connected, and selects wherein a road voltage and described RC circuit communication; Described RC circuit according to the charging and discharging state triggered timer of its electric capacity, by the discharge and recharge time of electric capacity described in timer record.
2. the circuit structure of negtive voltage detection device according to claim 1, is characterized in that: described RC circuit is RC integrating circuit, comprises operational amplifier, resistance and described electric capacity; The in-phase input end ground connection of described operational amplifier, after inverting input and described resistant series, is connected to described gating circuit, for being communicated with described negative voltage or reference voltage; Between the inverting input that described electric capacity is connected to described operational amplifier and output; Utilize the timer described in state change triggers of described operational amplifier output level.
3. the circuit structure of negtive voltage detection device according to claim 2, is characterized in that: the power end of described operational amplifier connects a dc source, earth terminal connected system ground.
4. the circuit structure of negtive voltage detection device according to claim 2, it is characterized in that: in described RC integrating circuit, be also provided with a comparator, the inverting input of described comparator connects the output of described operational amplifier, the in-phase input end ground connection of comparator, the timer described in low and high level change triggers utilizing comparator to export.
5. the circuit structure of negtive voltage detection device according to claim 4, is characterized in that: the power end of described comparator connects dc source, earth terminal connected system ground.
6. the circuit structure of negtive voltage detection device according to claim 4, is characterized in that: described timer is integrated in a processor, the interrupt interface of the output connection handling device of described comparator.
7. the circuit structure of the negtive voltage detection device according to any one of claim 1 to 6, it is characterized in that: in described gating circuit, be provided with two switching tubes, the control pole receiving path switching signal of two switching tubes, the switch ways of two switching tubes is connected between described negative voltage and RC circuit or is connected between described reference voltage and RC circuit.
8. the circuit structure of negtive voltage detection device according to claim 7, it is characterized in that: described switching tube is N-channel MOS pipe, the grid receiving path switching signal respectively of two N-channel MOS pipes, drain electrode connects one to one with described reference voltage and negative voltage to be detected respectively, the RC circuit described in source electrode connects.
9. a negtive voltage detection device, is characterized in that: be provided with the circuit structure according to any one of claim 1 to 8.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420838911.7U CN204302356U (en) | 2014-12-26 | 2014-12-26 | A kind of circuit structure of negtive voltage detection device and negtive voltage detection device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420838911.7U CN204302356U (en) | 2014-12-26 | 2014-12-26 | A kind of circuit structure of negtive voltage detection device and negtive voltage detection device |
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|---|---|
| CN204302356U true CN204302356U (en) | 2015-04-29 |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107329879A (en) * | 2017-07-05 | 2017-11-07 | 英业达科技有限公司 | Voltage monitoring circuit and voltage monitoring method |
| CN110095646A (en) * | 2019-04-24 | 2019-08-06 | 南京中感微电子有限公司 | Detection of negative pressure circuit and battery protecting circuit |
-
2014
- 2014-12-26 CN CN201420838911.7U patent/CN204302356U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107329879A (en) * | 2017-07-05 | 2017-11-07 | 英业达科技有限公司 | Voltage monitoring circuit and voltage monitoring method |
| CN107329879B (en) * | 2017-07-05 | 2020-08-28 | 英业达科技有限公司 | Voltage monitoring circuit and voltage monitoring method |
| CN110095646A (en) * | 2019-04-24 | 2019-08-06 | 南京中感微电子有限公司 | Detection of negative pressure circuit and battery protecting circuit |
| CN110095646B (en) * | 2019-04-24 | 2021-07-09 | 南京中感微电子有限公司 | Negative pressure detection circuit and battery protection circuit |
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