A kind of high freuqency accuracy High Linear atomizing piece control circuitTechnical field
The invention belongs to technical field of integrated circuits, the control circuit and method of more particularly to a kind of atomizing piece.
Background technology
Using high frequency oscillation, (frequency of oscillation is 1.7MHz or 2.4MHz to ultrasonic ultrasonic delay line memory, should more than the audibility range of peopleElectronic absolutely not injures to human body and animal), by the high-frequency resonant of ceramic atomizing piece, water and other liquid are broken up and producedSo elegant water smoke is born from, is not required to heat or add any chemical reagents.Compared with heating atomization mode, energy saving90%.But the characteristics of atomizing piece, is exactly：Could only produce optimal atomizing effect in resonance point, driving frequency slightly offset fromResonance point, atomization quantity just drastically decline.The method for producing driving frequency using RC oscillators in the industry at present, frequency degree of regulationIt is low, influenceed greatly by process deviation and temperature, the easy off-resonance point of frequency.
The regulation of high-precision High Linear is realized in the range of 1.5MHz to 4.5MHz, reaches and 2KHz frequencies is less than with stepping accuracyRate changes, it is necessary to adjustable more than 1000 steps, is necessarily required to bigger electric capacity in existing tune capacitive way, so meeting in the chipsDramatically increase cost.
As patent application 201510477493.2 discloses a kind of ultrasonic atomization piece high accuracy frequency sweep circuit, includingBooster circuit and frequency sweep circuit, booster circuit electrically connect with frequency sweep circuit, and propose the side that frequency sweep is carried out based on frequency sweep circuitMethod, including input fixed DC voltage and fixed frequency to booster circuit；Driven to frequency sweep circuit incoming frequency；Record boosting electricityThe magnitude of voltage of the Voltage Feedback point on road；Increase to frequency sweep circuit incoming frequency；Record the voltage of the Voltage Feedback point of booster circuitValue, and judge whether reach rated value to the frequency that frequency sweep circuit inputs, if so, terminate to scan and analyze the magnitude of voltage of record,The centre frequency of atomizing piece is found, otherwise into previous step.The present invention is applied to various ultrasonic atomization piece frequency measurements and driveIt is dynamic；The peak measurement of pulse signal is not needed upon, therefore the ultrasonic atomization piece frequency that can carry out megahertz rank is sweptRetouch；Difference compensation need not be carried out to the atomizing piece of different model, any ultrasonic atomization piece can be driven.However, the patent ShenPlease perform a scan and control by atomizing piece scanning circuit, can not solve the defects of adjusting capacitive way increase cost.
In a word, the method that current traditional RC circuits produce driving frequency, by area and structural constraint realize it is high-precisionIt is more difficult to spend FREQUENCY CONTROL aspect.
The content of the invention
Based on this, therefore the present invention primary mesh be to provide a kind of high freuqency accuracy High Linear atomizing piece control circuit,The circuit produces high-precision High Linear, the atomizing piece driving frequency of small stepping using phaselocked loop.
It is to provide a kind of high freuqency accuracy High Linear atomizing piece control circuit, the circuit leads to another mesh of the present inventionCross sigma-delta phaselocked loop and realize the configurable of frequency, realize high accuracy, High Linear regulation accurately controls atomizing piece to be operated in resonancePoint.
To achieve the above object, the technical scheme is that：
A kind of high freuqency accuracy High Linear atomizing piece control circuit, it includes PLL unit, control unit and atomizing piece listMember, wherein, the control signal that the PLL unit receives control unit produces a specific frequency square wave, and control unit receives atomizationVoltage signal caused by piece, produces control signal, and atomization blade unit receives square wave caused by PLL unit and drives and export a voltageSignal.
The PLL unit could be arranged to 1.5MHz~4.5MHz by the frequency range exported after frequency dividing, for drivingThe atomizing piece of different model.
Further, the PLL unit includes：PFD units, CP units, LPF units, VCO unit and sigma-delta divider are mono-Member；The PFD units, CP units, LPF units, VCO unit are sequentially connected, and PFD units meet Fref reference frequencies and dividerCrossover frequency produces pulse signal, and the pulse signal that CP units connect PFD units produces charging and discharging currents, and it is mono- that LPF units receive PFDThe charging and discharging currents of member produce voltage signal, and VCO receives frequency corresponding to the voltage signal generation of LPF units, sigma-deltaDivider units, which connect the output frequency generation crossover frequency of VCO unit and exported, gives PFD units.
Described control unit output control signal acts on sigma-delta divider (programmable frequency divider), and three rank Σ of configuration-Δ divider frequency dividing ratio, to adjust output frequency.
Further, programmable frequency divider controls the divide ratio of programmable frequency divider to change according to certain rule by algorithm(div_int is the integral frequency divisioil system of configuration) so that last Fvco output frequency such as following formula relation：
The circuit that the present invention is realized, small stepping can be used, high precision, the method for high linearity hair, is more accurately searchedRope ensures best nebulization efficiency to the optimum resonant frequency of atomizing piece.
The present invention makes sigma-delta divider units by way of being segmented and dividing, in 1.5MHz~4.5MHz output frequencyIn the range of produce the frequency that stepping is less than 2KHz, and stepping is small, and linearity height can more accurately search atomizing piece mostGood resonant frequency, ensure best nebulization efficiency.
Brief description of the drawings
Fig. 1 is the circuit diagram that the present invention is implemented.
Fig. 2 is the structural representation that the present invention implements PLL unit.
Embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, it is right below in conjunction with drawings and ExamplesThe present invention is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, andIt is not used in the restriction present invention.
As shown in figure 1, the high freuqency accuracy High Linear atomizing piece control circuit that the present invention is realized, it is mono- that it includes PLLMember, control unit and atomization blade unit, wherein, the control signal that PLL unit receives control unit produces a specific frequency square wave.Control unit receives voltage signal caused by atomizing piece, produces control signal.Atomization blade unit receives square wave caused by PLL unitDrive and export a voltage signal.
The PLL unit of the present embodiment could be arranged to 1.5MHz~4.5MHz by the frequency range exported after frequency dividing, useIn the atomizing piece of driving different model.Atomizing piece can produce a specific magnitude of voltage when resonance point works, when atomizing piece is defeatedGo out magnitude of voltage to change, illustrate that frequency of oscillation has had deviated from optimum resonance point, as control unit to electric caused by atomizing piecePressure is calculated and compared, and one group of control signal of output makes PLL unit output frequency readjust optimum resonant frequency.
The PLL unit of the present embodiment as shown in Fig. 2 including：PFD units, CP units, LPF units, VCO unit, sigma-deltaDivider units.PFD units connect Fref reference frequencies and divider crossover frequencies produce pulse signal.It is mono- that CP units meet PFDThe pulse signal of member produces impulse electricity electric current.The impulse electricity electric current that LPF units receive PFD units produces voltage signal.VCO receivesFrequency corresponding to the voltage signal generation of LPF units.The output frequency that sigma-delta divider units connect VCO unit produces frequency dividing frequencyRate.
Control unit output control signal acts on sigma-delta divider (programmable frequency divider), configures third order sigma-deltaDivider frequency dividing ratio, to adjust output frequency, the effect of programmable frequency divider is to control programmable frequency divider by algorithmDivide ratio changes (the integral frequency divisioil system that div_int is configuration) according to certain rule so that last Fvco output frequencySuch as following formula relation：
Found out by formula, div_frac often increases and reduced a value, Fvco change 244Hz frequencies, much smaller than 2KHz steppingsIt is required that.
The circuit that the present invention is realized, small stepping can be used, high precision, the method for high linearity hair, is more accurately searchedRope ensures best nebulization efficiency to the optimum resonant frequency of atomizing piece.
The present invention makes sigma-delta divider units by way of being segmented and dividing, in 1.5MHz~4.5MHz output frequencyIn the range of produce the frequency that stepping is less than 2KHz, and stepping is small, and linearity height can more accurately search atomizing piece mostGood resonant frequency, ensure best nebulization efficiency.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all essences in the present inventionAll any modification, equivalent and improvement made within refreshing and principle etc., should be included in the scope of the protection.