CN107465165B - Overload protection circuit of piezoelectric element and method thereof - Google Patents
Overload protection circuit of piezoelectric element and method thereof Download PDFInfo
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- CN107465165B CN107465165B CN201610415627.2A CN201610415627A CN107465165B CN 107465165 B CN107465165 B CN 107465165B CN 201610415627 A CN201610415627 A CN 201610415627A CN 107465165 B CN107465165 B CN 107465165B
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- 238000005070 sampling Methods 0.000 claims abstract description 23
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- 238000006243 chemical reaction Methods 0.000 claims description 30
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- 238000010168 coupling process Methods 0.000 claims description 3
- 238000005859 coupling reaction Methods 0.000 claims description 3
- 230000003321 amplification Effects 0.000 claims 2
- 238000003199 nucleic acid amplification method Methods 0.000 claims 2
- 230000001276 controlling effect Effects 0.000 abstract description 6
- 230000001105 regulatory effect Effects 0.000 abstract description 3
- 230000000875 corresponding effect Effects 0.000 description 16
- 230000000694 effects Effects 0.000 description 15
- 238000010586 diagram Methods 0.000 description 8
- 239000000463 material Substances 0.000 description 5
- 230000008859 change Effects 0.000 description 4
- 238000004088 simulation Methods 0.000 description 4
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- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 description 2
- 229910002113 barium titanate Inorganic materials 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
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- 239000002131 composite material Substances 0.000 description 2
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- 238000004519 manufacturing process Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 description 1
- 241000208340 Araliaceae Species 0.000 description 1
- 229910003327 LiNbO3 Inorganic materials 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 235000005035 Panax pseudoginseng ssp. pseudoginseng Nutrition 0.000 description 1
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Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
Abstract
The invention discloses an overload protection circuit of a piezoelectric element and a method thereof. The current sampling unit samples the analog signal according to a plurality of control codes in sequence to sample the signal. Wherein the magnitude of the analog signal is related to the magnitude of the operating current of the piezoelectric element. The regulation and control unit sequentially generates a plurality of control codes, and compares the potential of the reference signal with a critical value after acquiring the corresponding reference signal according to the control code when the sampling signal is in a state transition state. When the electric potential of the reference signal is larger than the critical value, the regulating and controlling unit stops outputting the pulse modulation signal so as to stop the piezoelectric element from working.
Description
Technical field
The present invention proposes a kind of overload protecting circuit, the overload protecting circuit and its method of especially a kind of piezoelectric element.
Background technique
The phenomenon that piezoelectric effect is mutually converted for mechanical energy a kind of in dielectric substance with electric energy.Wherein, it can produce piezoelectricity
The dielectric substance of effect may be generally referred to as piezoelectric material.In the prior art, it is because it is brilliant that piezoelectric material, which has piezoelectric effect,
Caused by interatomic specific arrangement mode in lattice, and there can be the effect of stress field and field coupling.Therefore, pass through piezoresistive material
Piezoelectric element made of expecting can be widely used in numerous areas with piezoelectric effect.
In the prior art, piezoelectric effect, which can be divided into, turns the direct piezoelectric effect of electric energy for mechanical energy and electric energy is turned mechanical energy
Inverse piezoelectric effect.In the application of inverse piezoelectric effect, general mostly is the mechanical energy that is exported by piezoelectric element to drive
The external load that dynamic (or vibration) contacts therewith is to achieve the effect that using required.It, can when making example with external load for water
Drive water by the mechanical energy that piezoelectric element is exported so that water can be refined into because of the vibration of piezoelectric element it is subtle
Droplet.
Piezoelectric element is for a kind of frequency controlling elements.Therefore, when piezoelectric element is worked normally in fixed frequency and is driven
When dynamic external load is also in stable state, the operating current of piezoelectric element can be maintained at a small range variation.However, due to
External load may change for some reason, and the operating current of piezoelectric element is also changed therewith.Especially when the work of piezoelectric element
Electric current exceed because of the variation of external load piezoelectric element can load normal variation range when, probably cause the serious of piezoelectric element
It damages.
Summary of the invention
In view of this, the present invention provides the overload protecting circuit and its method of a kind of piezoelectric element, can be pressed in detecting
The operating current of electric device beyond can load normal variation range when stop piezoelectric element work, ruined to avoid piezoelectric element
Damage.
In one embodiment, a kind of overload protecting circuit of piezoelectric element includes current sampling unit and regulation unit.Electricity
Flowing sampling unit can be sequentially according to multiple control code sampled analog signals to generate sampled signal.Regulation unit can sequentially generate more
A control code, and after control code when transition occurs according to sampled signal obtains corresponding reference signal, comparison reference signal
Current potential and critical value, and in the current potential of reference signal be greater than critical value when, regulation unit stop output pulse modulation signal with
Piezoelectric element is set to stop working.Wherein, the size of analog signal is relevant to the size of the operating current of piezoelectric element.
In one embodiment, a kind of overload protection method of piezoelectric element, comprising receive analog signal, sequentially generate it is multiple
Control code, sequentially according to control code sampled analog signals with generate sampled signal, according to sampled signal occur transition when control
Code obtains the current potential and critical value of corresponding reference signal, comparison reference signal, and when the current potential of reference signal is greater than critical
When value, stop output pulse modulation signal so that piezoelectric element stops working.Wherein, the size of analog signal is relevant to piezoelectricity member
The size of the operating current of part.
In conclusion the overload protecting circuit and its method of the piezoelectric element of the embodiment of the present invention, pass through sampling piezoelectricity
The operating current of element, in detect piezoelectric element operating current be more than critical value when, can fast reaction and stop exporting
Pulse modulation signal is so that piezoelectric element stops working, to avoid the damage of piezoelectric element.
Describe detailed features and advantage of the invention in detail in embodiments below, content is enough to make any to be familiar with phase
Close those skilled in the art understand technology contents of the invention and implement accordingly, and according to content disclosed by this specification, apply for a patent model
It encloses and schema, it is any to be familiar with relevant art and be readily understood upon the relevant purpose of the present invention and advantage.
Detailed description of the invention
Fig. 1 is the summary equivalent circuit diagram of piezoelectric element.
Fig. 2 is the summary relational graph of the impedance versus frequency of piezoelectric element.
Fig. 3 is that the driving circuit of one embodiment of the invention drives the schematic diagram of piezoelectric element.
Fig. 4 is that the driving circuit of another embodiment of the present invention drives the schematic diagram of piezoelectric element.
Fig. 5 is the summary relational graph that analog signal is compared using multiple reference signals.
Fig. 6 is the schematic diagram of the overload protection method of the piezoelectric element of one embodiment of the invention.
Wherein, appended drawing reference:
100 piezoelectric element, 110 first driving electrodes
120 second driving electrodes, 200 overload protecting circuit
210 current sampling unit, 211 D/A conversion unit
212 comparing units 220 regulate and control unit
240 electric currents turn 250 noise canceling unit of voltage cell
260 amplifying unit, 270 resonant element
271 capacity cell, 272 switch module
273 inductance element A1 analog signals
C0 direct capacitance C1 dynamic capacity
D1-Dn control code F1 series resonance frequency
F2 parallel resonance frequency I1 operating current
L1 dynamic inductance R1 dynamic electric resistor
R2 resistance Sr1-Srn, Srx reference signal
Gnd ground potential Ss sampled signal
Sp pulse modulation signal Vcc power supply potential
ZmaxMaximum impedance value ZminMinimum impedance value
Step S10a generates analog signal according to operating current
Step S10b eliminates the noise in analog signal
Step S10c amplified analog signal
Step S11 receives analog signal
Step S12 sequentially generates multiple control codes
Step S13 is sequentially according to multiple control code sampled analog signals to generate sampled signal
Step S13a sequentially generates reference signal according to each control code
Step S13b generates sampled signal according to each reference signal and analog signal
Control code when transition occurs according to sampled signal for step S14 obtains corresponding reference signal
The current potential and critical value of step S15 comparison reference signal
Step S16a stops output pulse modulation signal, so that piezoelectric element stops working
Step S16b exports pulse modulation signal
Specific embodiment
In general, made by the application piezoelectric material of piezoelectric element 100, and reach mechanical energy and electricity by piezoelectric effect
The mutual conversion of energy.In this, general effect for converting mechanical energy into electric energy is known as direct piezoelectric effect, and converts electric energy to machine
The effect of tool energy is known as inverse piezoelectric effect.
In some state sample implementations, piezoelectric material applied by piezoelectric element 100 can be but be not limited to piezoelectric single crystal, example
Such as quartz, lithium niobate (LiNbO3), lithium tantalate (LiTaO3), piezoelectricity polycrystal (piezoelectric ceramics), such as barium titanate (BT), zirconium
Lead titanates (PZT) etc., piezopolymer, such as PVDF and its copolymer, polyvinyl fluoride etc. or piezo-electricity composite material, such as piezoelectricity
The two-phase composite material of ceramics and polymer.
Fig. 1 is the summary equivalent circuit diagram of piezoelectric element.Referring to Fig. 1, piezoelectric element 100 has the first driving electrodes
110 and second driving electrodes 120.In this, piezoelectric element 100 can be equivalent at by direct capacitance C0, dynamic capacity C1, dynamic inductance
Resonance circuit composed by L1 and dynamic electric resistor R1.Wherein, dynamic capacity C1, dynamic inductance L1 and dynamic electric resistor R1 be each other
It is series between the first driving electrodes 110 and the second driving electrodes 120, and two ends of direct capacitance C0 are respectively coupled to the first drive
Moving electrode 110 and the second driving electrodes 120, and the dynamic capacity C1, dynamic inductance L1 and dynamic electric being serially connected can be parallel to
Hinder R1.
Fig. 2 is the summary relational graph of the impedance versus frequency of piezoelectric element.Fig. 1 and Fig. 2 are please referred to, due to piezoelectric element 100
For a kind of frequency controlling elements, therefore when piezoelectric element 100 works in different frequency, impedance will change therewith.In this, work as pressure
When electric device 100 works in series resonance frequency F1, the equivalent circuit of piezoelectric element 100 is in resistive, and piezoelectric element 100
The rough size for being equal to dynamic electric resistor R1 of impedance magnitude and can have minimum impedance value Zmin；And when piezoelectric element 100 works in
When parallel resonance frequency F2, the equivalent circuit of piezoelectric element 100 is in inductive, and the impedance of piezoelectric element 100 can have maximum
Impedance value Zmax.Therefore, in being normally applied, piezoelectric element more than 100 works in series resonance frequency F1, so that piezoelectric element 100
Impedance can be minimum and the operating current I1 that passes through piezoelectric element 100 can have maximum value, and then piezoelectric element can be obtained
100 maximum machine can export.
Fig. 3 is the schematic diagram of the overload protecting circuit of the protection piezoelectric element of one embodiment of the invention, and Fig. 4 is this hair
The schematic diagram of the overload protecting circuit of the protection piezoelectric element of bright another embodiment.Please refer to Fig. 3 and Fig. 4, piezoelectric element
Electric energy can be switched to corresponding mechanical energy and export corresponding mechanical energy to external by 100 according to pulse modulation signal Sp actuation
Load (not shown).In a state sample implementation, the frequency of pulse modulation signal Sp generally can be humorous with connecting for piezoelectric element 100
Vibration frequency F1 is identical.Wherein, overload protecting circuit 200 can find the series connection for being equivalent to piezoelectric element 100 using frequency technology is chased after
The pulse modulation signal Sp of the frequency of resonance frequency F1.
In some embodiments, overload protecting circuit 200 can produce fixed frequency and (be equivalent to the series connection of piezoelectric element 100
Resonance frequency F1) pulse modulation signal Sp.In further embodiments, pulse modulation signal Sp also can by other circuits,
It is generated such as signal generating circuit (not shown), and overload protecting circuit 200 exportable one controls signal so far signal generation electricity
Road, so that this signal generating circuit can have the pulse modulation signal Sp of respective frequencies according to control signal output or stop exporting
Pulse modulation signal Sp.
In this, in the case where the external load no change of piezoelectric element 100, the operating current I1 of piezoelectric element 100 can
Tend to definite value (or being maintained at a small range variation).
After overload protecting circuit 200 determines the frequency (completion chases after frequency) of pulse modulation signal Sp, overload protecting circuit 200
The operating current I1 of piezoelectric element 100 can also be sampled, to detect whether piezoelectric element 100 overloads.
Overload protecting circuit 200 includes current sampling unit 210 and regulation unit 220.Current sampling unit 210 couples
Piezoelectric element 100, and regulate and control unit 220 and couple current sampling unit 210 and piezoelectric element 100.Current sampling unit 210 can
Multiple sample program is executed, and according to multiple control code D1-Dn caused by regulation unit 220 in sample program each time
The operating current I1 of piezoelectric element 100 is sampled, to export sampled signal Ss according to the result of sampling.Regulating and controlling unit 220 can basis
Control code when transition occurs for sampled signal Ss obtains corresponding reference signal, the rear current potential according to reference signal and default
Critical value is compared, and in the result of comparison be reference signal current potential be greater than critical value when, can fast reaction and stop
Pulse modulation signal Sp is exported, so that piezoelectric element 100 stops working.In this, sampled signal Ss occurs transition and refers to sampling letter
The level of number Ss is converted to logical one by logical zero, or during being converted to logical zero by logical one.
In some embodiments, current sampling unit 210 may include D/A conversion unit 211 and comparing unit
212.The input terminal of D/A conversion unit 211 is coupled to regulation unit 220.Two input terminals of comparing unit 212 distinguish coupling
It is connected to the output end of piezoelectric element 100 Yu D/A conversion unit 211.
D/A conversion unit 211 can be used to go out corresponding analog signal according to the numerical value conversion of digital signal defeated
Out.In this, D/A conversion unit 211 can generate multiple reference signal Sr1-Srn according to multiple control code D1-Dn.
In some embodiments, multiple control code D1-Dn can sequentially be generated in a manner of descending by regulation unit 220, also that is,
Control code D1 caused by regulation unit 220 will have greatest measure, and control code Dn caused by regulation unit 220 will have
Minimum value.But the present invention is not limited thereto, multiple control code D1-Dn also can by regulation unit 220 in a manner of ascending order sequentially
It generates, or is sequentially generated as regulation unit 220 with sequence defined in user and also may be used.
By taking multiple control code D1-Dn that descending mode sequentially generates as an example, D/A conversion unit 211 is according to first
First reference signal Sr1 that control code D1 is converted out is greater than second ginseng converted out according to second control code D2
Examine signal Sr2, and second reference signal Sr2 that D/A conversion unit 211 is converted out according to second control code D2
Be greater than the third reference signal Sr3 converted out according to third control code D3, and so on refer to and believe to the last one
Number Srn.
In some state sample implementations, D/A conversion unit 211 can be the digital mould that is mainly made of passive device
Quasi- converter (Digital to Analog Converter, DAC), for example, resistance-type digital analog converter or switch-capacitor
Formula digital analog converter, or the digital analog converter being mainly made of active member, such as weighted current source formula number
Analog converter or matrix currents source formula digital analog converter.However, the present invention is not limited thereto.In this, digital simulation
Converting unit 211 can have the R-2R type digital analog converter of simple architecture to realize, to reduce overload protecting circuit 200
Overall cost expend.
Comparing unit 212 has two input terminals, this two input terminal can be referred to as inverting input terminal and non-inverting input
End.Wherein, the inverting input terminal of comparing unit 212 is coupled to D/A conversion unit 211, and comparing unit 212 is non-anti-
Phase input terminal is coupled to piezoelectric element 100.
In some embodiments, overload protecting circuit 200 more may include that electric current turns voltage cell 240, and electric current turns voltage
Unit 240 is coupled between piezoelectric element 100 and the non-inverting input of comparing unit 212.Electric current turns voltage cell 240 can be by work
Make to be exported again after electric current I1 is converted into corresponding analog signal A1 to comparing unit 212.Wherein, electric current turns 240 institute of voltage cell
The size of the analog signal A1 of generation is to be relevant to the size of the operating current I1 of piezoelectric element 100.In this, analog signal A1 is
It is positively correlated with operating current I1.In other words, the operating current I1 of piezoelectric element 100 is bigger, then electric current turns voltage cell 240 and produced
Raw analog signal A1 is also bigger.
In addition, the size of the operating current I1 of piezoelectric element 100 be also relevant to piezoelectric element 100 impedance magnitude and its
The impedance magnitude of the external load of driving, and operating current I1 is negative about the impedance magnitude of piezoelectric element 100 and external
The impedance magnitude of load.Therefore, the size that electric current turns analog signal A11 caused by voltage cell 240 is also relevant to piezoelectricity member
The impedance magnitude of part 100 and the impedance magnitude of external load, and analog signal A1 is impedance of the negative about piezoelectric element 100
Size and the impedance magnitude of external load.In other words, it is bigger to turn analog signal A1 caused by voltage cell 240 for electric current, then
The impedance for representing impedance and the external load of piezoelectric element 100 is smaller, and the operating current I1 for flowing through piezoelectric element 100 is got over
Greatly.
In this, the impedance magnitude of piezoelectric element 100 is relevant to the frequency of pulse modulation signal Sp.At that time, piezoelectric element 100
Impedance be also blocked impedance.Therefore, when the frequency of pulse modulation signal Sp is fixed frequency, analog signal A1 can be only related
In the impedance of external load, and analog signal A1 is bigger, then the impedance for representing external load is smaller, and flows through piezoelectric element 100
Operating current I1 it is bigger.In other words, overload protecting circuit 200 can determine according to the size variation of analog signal A1 outer whereby
It is whether stable loading.
In some state sample implementations, it can be resistance R2 that electric current, which turns voltage cell 240, and one end is coupled to ground potential Gnd, such as
Zero potential, and the other end is coupled to the non-inverting input of piezoelectric element 100 Yu comparing unit 212 so that operating current I1 in
Form corresponding cross-pressure on resistance R2, and it is convertible go out corresponding analog signal A1 to comparing unit 212.Wherein, analog signal
A1 is a kind of voltage signal, and resistance R2 can be to determine resistance.
In this, comparing unit 212 is that electric current is turned to the analog signal A1 and multiple reference letters that voltage cell 240 is converted out
Number Sr1-Srn is sequentially compared one by one to generate sampled signal Ss.
In some implementation states, comparing unit 212 can be for by operational amplifier (operational amplifier) institute structure
At comparison circuit, but the present invention is not limited thereto.
In some embodiments, overload protecting circuit 200 further includes noise canceling unit 250, and noise canceling unit 250
It is coupled between piezoelectric element 100 and comparing unit 212.In this, noise canceling unit 250 can be coupled to voltage conversion unit
Between 240 and comparing unit 212, after eliminating via the noise on analog signal A1 caused by voltage conversion unit 240, then
Output to comparing unit 212 is compared.
In some state sample implementations, noise canceling unit 250 can be the filter as composed by capacitor, to filter out simulation letter
Noise on number A1, but the present invention is not limited thereto.
In some embodiments, overload protecting circuit 200 further includes amplifying unit 260, and amplifying unit 260 is coupled to pressure
Between electric device 100 and comparing unit 212.In this, amplifying unit 260 can be coupled to voltage conversion unit 240 and comparing unit
Between 212, after amplifying analog signal A1 caused by voltage conversion unit 240, then exports to comparing unit 212 and compared
Compared with.In addition, amplifying unit 260 can be also coupled between noise canceling unit 250 and comparing unit 212, so that analog signal A1
Amplify again via amplifying unit 260 after noise first being eliminated via noise canceling unit 250, is just exported later to comparing unit
212 are compared.
Therefore, the regulation unit 220 of overload protecting circuit 200 can sequentially generate control code D1-Dn to digital-to-analogue conversion
Unit 211, so that comparing unit 212 can be by analog signal A1 and D/A conversion unit 211 according to the first control code D1-Dn
Generated reference signal Sr1-Srn is sequentially compared, and generates sampled signal Ss to regulation unit 220, so that adjusting
Whether control unit 220 can occur transition according to sampled signal Ss to decide whether to continue sequentially to export control code D1-Dn.
In the state sample implementation that regulation unit 220 generates control code D1-Dn in a manner of descending, as shown in figure 5, in each
In sample program, firstly, D/A conversion unit 211 generates first reference signal Sr1 according to first control code D1, and
First reference signal Sr1 can be compared by comparing unit 212 with analog signal A1.Due to first reference signal at this time
The current potential of Sr1 is greater than the current potential of analog signal A1, and therefore, the level of sampled signal Ss caused by comparing unit 212 can be to patrol
It collects " 0 ".Until D/A conversion unit 211 generates x-th of reference signal Srx, and comparing unit according to x-th of control code
After 212 are compared x-th of reference signal Srx with analog signal A1, comparing unit 212 can be because judging x-th of reference signal
The current potential of Srx is less than the current potential of analog signal A1 and makes the level of sampled signal Ss by logical zero transition to logical one.And
When transition occurs for sampled signal Ss, regulation unit 220 can stop exporting next first control code, and according to current control
Code processed obtains the current potential via the corresponding reference signal Srx generated of D/A conversion unit 211, and by this reference signal Srx
Current potential as piezoelectric element 100 when driving external load, electric current turns voltage cell 240 according to the work of piezoelectric element 100
The maximum potential for the analog signal A1 that electric current I1 can be converted out.
And in the state sample implementation that regulation unit 220 generates control code D1-Dn in a manner of ascending order, in each sample program
In, when transition occurs for sampled signal Ss, regulation unit 220 can stop exporting next control code, and according to current control
Code processed obtains the current potential via the corresponding reference signal Srx generated of D/A conversion unit 211, and by this reference signal Srx
Current potential as piezoelectric element 100 when driving external load, electric current turns voltage cell 240 according to the work of piezoelectric element 100
The minimum level for the analog signal A1 that electric current I1 can be converted out.
And in regulation unit 220 in each sample program, to regulate and control in a state sample implementation of sequence defined in user
Unit 220 then can will all correspond to the current potential of each reference signal of the transition of sample signal Ss according to the transition of sampled signal Ss
Mean operation is carried out, and using the average value that this is obtained as piezoelectric element 100 in the frequency regulation that pulse modulation signal Sp is current
Under, electric current turns the analog signal A1 converted out that voltage cell 240 can be converted out according to the operating current I1 of piezoelectric element 100
Average potential.
Therefore, regulation unit 220 can face the current potential of reference signal obtained in each sample program with preset respectively
Dividing value is compared, and carries out corresponding actuation according to the result of the comparison.When the current potential that comparison result is reference signal is less than
Or when being equal to preset critical value, indicate that the variation of external load still in stability range, and flows through the work of piezoelectric element 100
Electric current I1 still can be in the range of load between piezoelectric element 100.Therefore, regulation unit 220 can normally export pulse modulation signal
Sp is so that piezoelectric element 100 works on.
And when the current potential that comparison result is reference signal is greater than the critical value of default, then it represents that the variation of external load
The operating current I1 for having exceeded stability range, and having flowed through piezoelectric element 100 exceeded piezoelectric element 100 can load range (that is,
Overload).Therefore, regulation unit 220 can fast reaction and stop export pulse modulation signal Sp so that piezoelectric element 100 stop work
Make, uses to protect piezoelectric element 100, damaged to avoid piezoelectric element 100 because of excessively high operating current I1.
In some embodiments, overload protecting circuit 200 more may include resonant element 270, and resonant element 270 is coupled to
Between piezoelectric element 100, regulation unit 220 and comparing unit 212.Resonant element 270 can be used to according to regulation 220 institute of unit
The pulse modulation signal Sp actuation of output, and then control the operating current I1 of piezoelectric element 100.
In some state sample implementations, resonant element 270 may include capacity cell 271, switch module 272 and inductance element
273.Wherein, one end of capacity cell 271 may be coupled to the first driving electrodes 110 of piezoelectric element 100.Inductance element 273 can
It is coupled between the other end of capacity cell 271 and a power supply potential Vcc.One end of switch module 272 may be coupled to comparison list
The non-inverting input of member 212, the other end of switch module 272 may be coupled to the other end and inductance element of capacity cell 271
273 one end, and the control terminal of switch module 272 is coupled to the output end of regulation unit 220.Therefore, switch module 272 can root
The electrical connection between capacity cell 271 and comparing unit 212 is controlled according to pulse modulation signal Sp.
In a state sample implementation, the second driving electrodes 120 of piezoelectric element 100 may be coupled to the non-anti-of comparing unit 212
Phase input terminal, as shown in Figure 3.However the present invention is not limited thereto, in another state sample implementation, as shown in figure 4, piezoelectric element
100 the second driving electrodes 120 then may be coupled to ground potential Gnd.
In some real aspects, D/A conversion unit 211, comparing unit 212 and the regulation of overload protecting circuit 200
Unit 220 can integrate circuit production in same chip (IC), and remaining electric current turns voltage cell 240, noise eliminates list
Member 250, amplifying unit 260 and/or resonant element 270 can be then the electronic component of external setting.However the present invention is not with this
It is limited, electric current turns voltage cell 240, noise canceling unit 250, amplifying unit 260 and/or resonant element 270 also can be with number
Analog-converted unit 211, comparing unit 212 and regulation unit 220 are with production of integrated circuits among same chip.
Fig. 6 is the schematic diagram of the overload protection method of the piezoelectric element of one embodiment of the invention.Fig. 3 is please referred to figure
6, the overload protection method of piezoelectric element 100 includes to receive analog signal A1 (step S11), sequentially generate multiple control code D1-
Dn (step S12), sequentially according to multiple control code D1-Dn sampled analog signals A1 to generate sampled signal Ss (step S13), root
Control code when transition occurring according to sampled signal obtain corresponding reference signal (step S14), comparison reference signal current potential with
Critical value (step S15), and when the current potential of reference signal is greater than critical value, stop output pulse modulation signal Sp so that pressure
Electric device 100 stops working (step S16a).In addition, when operating voltage is less than or equal to critical value, output pulse modulation letter
Number Sp (step S16b), to control the operating current I1 of piezoelectric element 100.
In this, the frequency of pulse modulation signal Sp can be fixed frequency, such as be fixed on the series resonance frequency of piezoelectric element 100
Rate F1 can be exported with obtaining maximum machine.Since piezoelectric element 100 is frequency controlling elements, when the frequency of pulse modulation signal Sp
When for fixed frequency, the impedance of piezoelectric element 100 can be blocked impedance, and make operating current I1 can be only in relation to piezoelectric element
The impedance of the 100 external loads driven.
In addition, the size of analog signal A1 is relevant to the size of the operating current I1 of piezoelectric element 100.In this, simulation is believed
Number A1 is the operating current I1 for being positively correlated with piezoelectric element 100, and impedance of the negative about external load.
In some embodiments, before step S11, overload protection method more may include generating simulation according to operating current I1
Signal A1 (step S10a).In this, overload protecting circuit 200 can turn voltage cell 240 according to piezoelectric element 100 by electric current
The size of operating current I1 converts out corresponding analog signal A1.
After step S10a, overload protection method more may include eliminating analog signal by noise canceling unit 250
Noise (step S10b) on A1.In addition, overload protection method more may include by 260 amplified analog signal A1 of amplifying unit
(step S10c).In this, step S10b and step S10c can be executed sequentially, after first eliminating the noise on analog signal A1, then
Amplified analog signal A1.However, the present invention is not limited thereto, overload protection method also can only execute step S10b or step
S10c。
In a state sample implementation of step S11, overload protecting circuit 200 can be single by the comparison of current sampling unit 210
Member 212 receives analog signal A1.In this, comparing unit 212 is to receive analog signal A1 with its non-inverting input.
In a state sample implementation of step S12, the regulation unit 220 of overload protecting circuit 200 can be used descending mode, rise
Sequential mode or the customized sequence of user sequentially generate multiple control code D1-Dn.
In a state sample implementation of step S13, can by current sampling unit 210 D/A conversion unit 211 according to
Sequence generates reference signal Sr1-Srn (step S13a) according to each control code D1-Dn, and by the comparison of current sampling unit 210
Unit 212 generates sampled signal Ss (step S13b) according to each reference signal Sr1-Srn and analog signal A1.
In this, when comparing unit 212 determines that analog signal A1 is greater than reference signal by comparison, comparing unit 212
The level of generated sampled signal Ss can be logical one.And when comparing unit 212 determines that analog signal A1 is less than by comparison
Reference signal when, the level of sampled signal Ss caused by comparing unit 212 then can be logical zero.In addition, step S11 is arrived
Step S13 can be described as a sample program.
In a state sample implementation of step S14, the regulation unit 220 of overload protecting circuit 200 can be in this sample program
Control code when the middle generation transition according to sampled signal Ss obtains the reference via generation corresponding to D/A conversion unit 211
Signal Srx.It connects, executes step S15, overload protecting circuit 200 can be by regulating and controlling unit 220 for the current potential of reference signal Srx
It is compared with preset critical value.
When the current potential that comparison result is reference signal Srx is greater than critical value, indicate that the variation of external load has exceeded
Stability range, and the operating current I1 for passing through piezoelectric element 100 exceeded piezoelectric element 100 can load range (that is, mistake
It carries).Therefore, step S16a can be performed, the regulation unit 220 of overload protecting circuit 200 can stop exporting pulse modulation signal
Sp, to stop the actuation of resonance circuit 270 so that piezoelectric element 100 can stop working, to avoid piezoelectric element 100 because
Excessively high operating current I1 and damage.
Conversely, being indicated external when the current potential that comparison result is reference signal Srx is less than or equal to preset critical value
The variation of load is still in stability range, and the operating current I1 for flowing through piezoelectric element 100 still can load between piezoelectric element 100
In the range of.Therefore, then step S16b can be performed, the regulation unit 220 of overload protecting circuit 200 can normally export pulse modulation
Signal Sp is so that piezoelectric element 100 works on.
In some embodiments, after step S16b, can accent execute above-mentioned process step, with piezoelectricity of resampling
The operating current I1 of element 100, uses whether supervision piezoelectric element 100 in real time occurs overload condition.
In some embodiments, after step S16a, the more exportable police of regulation unit 220 of overload protecting circuit 200
Show signal (not shown), to warn user to have abnormality.
In conclusion the overload protecting circuit and its method of the piezoelectric element of the embodiment of the present invention, pass through sampling piezoelectricity
The operating current of element, in detect piezoelectric element operating current be more than critical value when, can fast reaction and stop exporting
Pulse modulation signal is so that piezoelectric element stops working, to avoid the damage of piezoelectric element.
Technology contents of the invention are disclosed with preferred embodiment as above-mentioned, and however, it is not to limit the invention, any
Those skilled in the relevant technical field, do not depart from spirit of the invention do it is a little change and retouch, but these changes
It should be all covered by the protection scope of appended claims of the present invention with retouching.
Claims (16)
1. a kind of overload protecting circuit of piezoelectric element, characterized by comprising:
One current sampling unit sequentially samples an analog signal according to multiple control codes to generate a sampled signal, the wherein mould
The size of quasi- signal is relevant to the size of the operating current of a piezoelectric element；And
One regulation unit, sequentially generates multiple control code, and the control code acquirement pair when transition occurs according to the sampled signal
After the reference signal answered, compare the current potential and a critical value of the reference signal, and being greater than in the current potential of the reference signal should
When critical value, stop one pulse modulation signal of output so that the piezoelectric element stops working.
2. the overload protecting circuit of piezoelectric element as described in claim 1, which is characterized in that the current sampling unit includes:
One D/A conversion unit generates multiple reference signals according to multiple control code；And
One comparing unit generates the sampled signal according to the respectively reference signal and the analog signal.
3. the overload protecting circuit of piezoelectric element as described in claim 1, which is characterized in that when the current potential of the reference signal
When less than or equal to the critical value, which exports the pulse modulation signal to control the work of piezoelectric element electricity
Stream.
4. the overload protecting circuit of piezoelectric element as described in claim 1, which is characterized in that further include:
One electric current turns voltage cell, generates the corresponding analog signal according to the operating current of the piezoelectric element.
5. the overload protecting circuit of piezoelectric element as described in claim 1, which is characterized in that further include:
One amplifying unit amplifies the analog signal, and wherein the current sampling unit sequentially samples according to multiple control code and amplifies
The analog signal afterwards is to generate the sampled signal.
6. the overload protecting circuit of piezoelectric element as claimed in claim 5, which is characterized in that further include:
One noise canceling unit eliminates the noise in the analog signal, and wherein amplifying unit amplification is eliminated single via the noise
Member eliminates the analog signal after the noise in the analog signal.
7. the overload protecting circuit of piezoelectric element as described in claim 1, which is characterized in that further include:
One resonant element controls the operating current of the piezoelectric element according to the frequency of the pulse modulation signal.
8. the overload protecting circuit of piezoelectric element as claimed in claim 7, which is characterized in that the resonant element includes:
One capacity cell, one end are coupled to one end of the piezoelectric element；
One switch module is coupled between the other end of the capacity cell and the current sampling unit, and according to the pulse modulation
Signal controls the electrical connection of the capacity cell Yu the current sampling unit；And
One inductance element is coupled between the other end of the capacity cell and a power supply potential.
9. the overload protecting circuit of piezoelectric element as claimed in claim 8, which is characterized in that the other end coupling of the piezoelectric element
It is connected to a ground potential.
10. the overload protecting circuit of piezoelectric element as claimed in claim 8, which is characterized in that the other end of the piezoelectric element
It is coupled to the current sampling unit.
11. a kind of overload protection method of piezoelectric element, characterized by comprising:
An analog signal is received, wherein the size of the analog signal is relevant to the size of the operating current of a piezoelectric element；
Sequentially generate multiple control codes；
The analog signal is sequentially sampled to generate a sampled signal according to multiple control code；
Control code when transition occurring according to the sampled signal obtains a corresponding reference signal；
Compare the current potential and a critical value of the reference signal；And
When the current potential of the reference signal is greater than the critical value, stop one pulse modulation signal of output so that the piezoelectric element stops
Only work.
12. the overload protection method of piezoelectric element as claimed in claim 11, which is characterized in that sequentially according to multiple control
Code samples the analog signal to generate:
The reference signal is sequentially generated according to the respectively control code；And
The sampled signal is generated according to the respectively reference signal and the analog signal.
13. the overload protection method of piezoelectric element as claimed in claim 11, which is characterized in that further include:
When the current potential of the reference signal is less than or equal to the critical value, the pulse modulation signal is exported to control piezoelectricity member
The operating current of part.
14. the overload protection method of piezoelectric element as claimed in claim 11, which is characterized in that further include:
The analog signal is generated according to the operating current.
15. the overload protection method of piezoelectric element as claimed in claim 11, which is characterized in that before the receiving step more
Include: amplifying the analog signal.
16. the overload protection method of piezoelectric element as claimed in claim 15, which is characterized in that before the amplification procedure more
Include: eliminating the noise in the analog signal.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW105117887A TWI591924B (en) | 2016-06-06 | 2016-06-06 | Overload Protection Circuit Of Piezoelectric Element |
| TW105117887 | 2016-06-06 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107465165A CN107465165A (en) | 2017-12-12 |
| CN107465165B true CN107465165B (en) | 2019-06-04 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620570734.8U Withdrawn - After Issue CN205681094U (en) | 2016-06-06 | 2016-06-14 | Overload protection circuit for piezoelectric element |
| CN201610415627.2A Active CN107465165B (en) | 2016-06-06 | 2016-06-14 | Overload protection circuit of piezoelectric element and method thereof |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620570734.8U Withdrawn - After Issue CN205681094U (en) | 2016-06-06 | 2016-06-14 | Overload protection circuit for piezoelectric element |
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|---|---|
| CN (2) | CN205681094U (en) |
| TW (1) | TWI591924B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI591924B (en) * | 2016-06-06 | 2017-07-11 | 盛群半導體股份有限公司 | Overload Protection Circuit Of Piezoelectric Element |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62122761A (en) * | 1985-11-23 | 1987-06-04 | Nec Corp | Piezoelectric printing head drive circuit |
| CN101728973A (en) * | 2008-10-31 | 2010-06-09 | 鸿富锦精密工业（深圳）有限公司 | Driving device and overload protection method thereof |
| CN102832941A (en) * | 2012-10-07 | 2012-12-19 | 复旦大学 | Successive approximation type analog-digital converter capable of pre-detecting input range of comparer |
| CN103166473A (en) * | 2012-01-17 | 2013-06-19 | 崇贸科技股份有限公司 | Adaptive sampling circuit for detecting the demagnetized voltage of the transformer |
| CN205681094U (en) * | 2016-06-06 | 2016-11-09 | 合泰半导体(中国)有限公司 | Overload protection circuit for piezoelectric element |
-
2016
- 2016-06-06 TW TW105117887A patent/TWI591924B/en active
- 2016-06-14 CN CN201620570734.8U patent/CN205681094U/en not_active Withdrawn - After Issue
- 2016-06-14 CN CN201610415627.2A patent/CN107465165B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62122761A (en) * | 1985-11-23 | 1987-06-04 | Nec Corp | Piezoelectric printing head drive circuit |
| CN101728973A (en) * | 2008-10-31 | 2010-06-09 | 鸿富锦精密工业（深圳）有限公司 | Driving device and overload protection method thereof |
| CN103166473A (en) * | 2012-01-17 | 2013-06-19 | 崇贸科技股份有限公司 | Adaptive sampling circuit for detecting the demagnetized voltage of the transformer |
| CN102832941A (en) * | 2012-10-07 | 2012-12-19 | 复旦大学 | Successive approximation type analog-digital converter capable of pre-detecting input range of comparer |
| CN205681094U (en) * | 2016-06-06 | 2016-11-09 | 合泰半导体(中国)有限公司 | Overload protection circuit for piezoelectric element |
Also Published As
| Publication number | Publication date |
|---|---|
| TW201743528A (en) | 2017-12-16 |
| TWI591924B (en) | 2017-07-11 |
| CN205681094U (en) | 2016-11-09 |
| CN107465165A (en) | 2017-12-12 |
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