Embodiment
A kind of non-contact charger, form by charger and portable equipment two parts, charger partly converts electric energy to the alternating magnetic field of a fixed frequency, the portable equipment part is cut the magnetic line of force of this alternating magnetic field by inductance, converting magnetic energy to electric energy provides charging voltage for inner battery, it is characterized in that the electric energy of portable set is that the space coupling by electromagnetic field obtains, and does not need to contact with charger by electric conducting material when portable set obtains electric energy.
The operation principle block diagram of this non-contact charger is referring to Fig. 2, and charger partly comprises charging signals generation module, power driver module, transmission tuning part, feedback signal detection module, time block, NOR gate, power module.Wherein the major function of charger part has 3 points: 1, produce the alternating magnetic field that frequency is 120KHz, be characterized in that this magnetic field has bigger power and stable frequency.2, whether the position of detecting portable equipment is in effective charging magnetic field range.Charger does not enter step operating state when 3, having detected portable equipment in effective magnetic field.
Portable equipment partly comprises electric energy acquisition module, rectifying and voltage-stabilizing module, charge management module.Its major function has following 3 points: the alternating magnetic field that 1, with frequency is 120KHz converts alternating voltage to, is characterized in selecting and converting magnetic energy to electric energy with higher efficient the frequency in magnetic field.2, alternating voltage being converted to galvanic current presses to internal cell and components and parts power supply.3, to the detection and the control of inner battery charge cycle.
Below the block diagram principle of charger part is analyzed:
Referring to Fig. 3, charging signals generation module has two output signals and a stop signal input, and output signal is that two frequencies are that 120KHz and phase angle differ 180 ° pulse signal.This signal is sent to power driver module and carries out the electric current amplification, when pulse current when sending tuning coil at magnetic core inner and around produce magnetic field, because inductance L 1, L2 are to take turns conducting according to the frequency of 120KHz, and the conducting opposite current of L1, L2, therefore final this magnetic field that produces is an alternating magnetic field that frequency is 120KHz, finishes the conversion of electric energy to magnetic energy by such process.
In use portable set has the most of the time not charge on charger, therefore the main power consumption of charger circuit partly can be quit work during this period, do not only effective conservation of power resource like this but also can prolong useful life of charger circuit.Add stop control signal in charging signals generation module, stop signal is produced by " NOR gate " back by feedback signal module and time block for this reason.When the feedback signal detection module detected portable set on cradle the time output signal A be the logical one level, because 1 " or " any number equals " 1 ", this moment, the signal of timer module output became irrelevant signal, stop signal C=not A=" 0 ", this moment charging signals generator operate as normal, output signal A is a logical zero when not having portable set on cradle when the feedback signal detection module detects, because 0 " or " any number equals " any number ", so stop signal C=not B, stop signal C only depends on the B signal, the B signal is to be 1.8% pulse signal by the duty ratio that timer module produces, the time of output logic " 1 " is 80ms in a pulse period, the time of output logic " 0 " is about 4.5s, that is to say, this moment, the charging signals generator was worked once every 4.5s, and each operating time is 80ms.
Below the implementation of each main functional modules in the block diagram is analyzed.
One, charging signals generation module and power driver module.
Two, feedback signal detection module.
Three, time block.
Four, electric energy acquisition module.
1, charging signals generation module and power driver module.
The schematic diagram of charging signals generation module and power driver module is referring to Fig. 3.Charging signals generation module is a circuit that constitutes with the SG3524 integrated chip, and it is the both-end output type pulsewidth modulated intergrated circuit that American Silicon General Corporation (SiliconGeneral) produces.
DC power supply V
sFrom delivering to the input of reference voltage pressurizer after pin 15 inserts, produce stable+5V reference voltage.+ 5V delivers to other components and parts of inside (or outside) circuit again as reference power supply.Oscillator pin 7 external capacitor C
T, pin 6 outer meeting resistance R
TOscillator frequency f is by outer meeting resistance R
TAnd capacitor C
TDecision, f=1.18/R
TC
T, in this circuit, pass through R
T, C
TSetting f is designed to 240KHz.The output of oscillator is divided into two-way, and one the tunnel delivers to flip and flop generator and two NOR gate with the clock pulse form, and the in-phase end of comparator, the output of the reverse termination error amplifier of comparator are delivered to the sawtooth waveforms form in another road.
Error amplifier A1 is actually a differential amplifier, and pin 1 is its reverse input end, and pin 2 is its in-phase input end.In-phase input end is received the voltage of obtaining 2.5V on the divider resistance of reference voltage, another input end grounding.The output voltage V a and the sawtooth voltage of error amplifier compare in comparator, thereby a PWM square-wave pulse that changes width with the output voltage error amplifier height appears in the output at comparator, the duty ratio of square-wave pulse was 50% when comparative voltage Va equaled 2.5V, and the duty ratio of the low more square-wave pulse of Va is big more.Again this square-wave pulse is delivered to an input of NOR gate.Two inputs in addition of NOR gate are respectively flip and flop generator and oscillator sawtooth waveforms.High-low level is alternately exported in two output complementations of flip and flop generator, and its effect is a base stage of pwm pulse alternately being delivered to two triode V1 and V2.At last, transistor T 1 and T2 be the output pulse width modulating wave respectively, 180 ° of both phase phasic differences.Pulse frequency is 1/2 of an oscillator frequency.When pin 10 adds high level, make the transistor saturation conduction of breaking circuit inside, Va is pulled into 0V, make that the output of PWM comparator is permanent to be high level, can realize that promptly oxide-semiconductor control transistors V1, V2 end to the blockade of output pulse after anti-phase by NOR gate.Between charging signals generation module and power driver module, also added the Current Negative Three-Point Capacitance signal in addition, feedback resistance R4 is concatenated on the current circuit of load, when load current has produced feedback voltage V f during by R4, Vf=i1*R4, Vf is sent in the current limliting comparator, Vf also increases simultaneously when loading coil current i 1 increases, the current limliting comparator is output as high level under the normality, in case with regard to output low level, Va can be pulled into 0V equally and make transistor V1, V2 end when the pressure drop on the R4 surpasses 200mV.The maximum load current of design can be by determining the adjustment of R4 resistance.
Power driver module has adopted the CMOS pipe to make current amplifier spare, be characterized in that input impedance height and drive current are big, its operation principle is comparatively simple, the conducting in turn of two CMOS pipes produces the alternating magnetic field that frequency is 120KHz on load inductance L1, L2 under the output control of SG3524.
2, feedback signal detection module
The circuit theory diagrams of feedback signal detection module are referring to Fig. 4.It by magnetic=>power conversion circuit and current rectifying and wave filtering circuit constitute.Magnetic=>power conversion circuit mainly contains inductive sensor L3 and forms, inductance L 3 is on the auxiliary winding of elementary magnetic core, when the secondary magnetic core of portable set end near first utmost point magnetic core with the time, inductance L 3 two ends produce ac induction voltage, will produce a stable logic level output after this ac voltage rectifier, the filtering.The result who finally obtains is: when the secondary magnetic core of portable set end feedback signal detection module output logic " 1 " during near cradle, detection module output logic " 0 " when keeping clear of.When detection module was output as " 1 ", " NOR gate " was output as " 0 "
3, time block
Time block is a circuit that constitutes with NE555 type integrated chip, and its effect is to produce one by one that duty ratio is 1.8%, the fixed pulse signal that the about 0.2HZ of frequency is.Its circuit theory diagrams are referring to Fig. 5.
As seen from the figure, NE555 inside comprises discharge transistor T1, two voltage comparator A1 and A2, rest-set flip-flop and be made up of three resistance (resistance respectively is 5K Ω).
Supply voltage rigidly connects when leading to, capacitor C 1 both end voltage Vc1 is less than 1/3Vcc, the output level of comparator A1, A2 is respectively " 1 ", " 0 ", and rest-set flip-flop obtains this state input back output Q=1/Q=0 (state table of rest-set flip-flop is referring to table 1), and discharge transistor T1 ends.The energising back Vcc give capacitor C1 charging by resistance R 1 and diode D1, Vc1 raises gradually, A1 when Vc1>1/3Vcc, the output level of A2 is respectively " 1 ", " 1 ", it is constant that rest-set flip-flop obtains this state input back output state, remain Q=1/Q=0, discharge transistor T1 ends, Vcc continues to give capacitor C1 charging by resistance R 1 and diode D1, A1 when Vc1>2/3Vcc, the output level of A2 is respectively " 0 ", " 1 ", rest-set flip-flop obtains this state input back output state counter-rotating, output Q=0/Q=1, discharge transistor T1 conducting this moment, electric charge on the capacitor C1 passes through R2, D2 discharges, Vc1 voltage reduces gradually, A1 during 1/3Vcc<Vc1<2/3Vcc, the output level of A2 remains " 0 ", " 1 ", rest-set flip-flop obtains this state input back output state counter-rotating when Vc1<1/3 Vcc, T1 ends, the operating state of NE555 is got back to original state again, and C1 begins the charge and discharge process of next cycle again, and the waveform of C1 charge and discharge process and Q point output waveform are referring to Fig. 6.Just can change the output duty of ratio in this resistance size that needs to change R1, R2.
4, electric energy acquisition module
The design of electric energy acquisition module is in the inside of portable set, it is mainly by secondary magnetic core for its structure comparatively simple (referring to figure), 1 three parts of inductance L 1 and capacitor C are formed and the employing parallel connection method, when the secondary magnetic core in the portable set near and during elementary subsides core in cradle, secondary iron core can produce the magnetic line of force with the logical frequency of elementary iron core, when the magnetic line of force passes through in inductance L 1, it is moving that inductance L 1 is done the magnetic line of force relatively, and at the alternating voltage of coil two ends generation with magnetic line of force same frequency, the regulator rectifier circuit by portable set inside converts this alternating current to galvanic current to in-line power again.Effect at this capacitor C1 is to form an antiresonant circuit with inductance L 1, and resonance frequency is designed to 120KHz.Adopted that to have only frequency behind the resonance be the electromagnetic field of 120KHz
High conversion efficiency non-contact charger of the present invention is owing to adopt electromagnetism noncontact coupled modes to carry out the electric energy conversion, make equipment save charging electrode, thereby efficiently solve the inherent shortcoming that the contact charging modes exists, in addition, the present invention is directed to the improvement of leakage field, magnetic hysteresis loss and coil loss, and,, reach safety, purpose efficiently to the selection of elementary, secondary oscillating circuit form and concrete method of attachment according to the characteristics of series/parallel oscillating circuit.
The present invention also has some other distortion or improvement.If those skilled in the art are subjected to the change or the improvement of the conspicuous unsubstantiality that inspiration of the present invention makes, all belong to the protection range of claims of the present invention.