Embodiment
Below in conjunction with the Figure of description in the present invention, the technical scheme in invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, rather than whole embodiment.Embodiment based in the present invention, those of ordinary skills, not making under the creative work prerequisite the every other embodiment obtained, belong to the scope of protection of the invention.
Shown in Figure 1, one embodiment of the invention provides a kind of active clamped ortho-exciting electric source circuit, comprises EMC module 101, BOOST boost module 102, active clamped normal shock module 103, driver module 104, the BUCK module 105 of series connection successively;
Described EMC module 101, input and output are all alternating voltage, the differential mode and the common mode disturbances that for suppressing circuit, produce;
Described BOOST boost module 102, be input as alternating voltage, is output as the direct voltage that is greater than 200 volts, the impact for reducing harmonic wave on described power circuit;
Described active clamped normal shock module 103, be input as the direct voltage that is greater than 200 volts, is output as and is less than 30 volts of direct voltages, adopted the resonant reset mode;
Described driver module 104, be used to described active clamped normal shock module that driving voltage is provided;
Described BUCK module 105, beyond the signals collecting range of frequency bandwidths that operating frequency is arranged on to cellanalyzer.
It should be noted that, described BOOST boost module 102 boosts and becomes the 400V direct current for the input voltage by after AC rectification, and circuit adopts the critical conduction mode control mode, through described BOOST boost module 102, can effectively reduce the impact of harmonic wave on electrical network, the PF value can reach more than 0.9
Shown in Figure 2, as an embodiment, described active clamped normal shock module 103 specifically comprises: it is a loop that the winding A of transformer T1 connects with clamped switching tube Q4, clamped capacitor C 3, the input that the Same Name of Ends 1 of winding A is active clamped normal shock module; Main switch Q5 is serially connected between the different name end 2 and ground of winding A;
It is a loop that the winding B of transformer T1 connects with continued flow tube Q7, forward switching tube Q6, the common end grounding of continued flow tube Q7 and forward switching tube Q6; The Same Name of Ends 3 of one termination winding B of the second inductance L 2, the other end is as the output of active clamped normal shock module; Be parallel with the 4th capacitor C 4 and the 6th resistance R 6 between the output of active clamped normal shock module and ground.
It should be noted that, described clamped switching tube Q4, main switch Q5, continued flow tube Q7, forward switching tube Q6 are the N-type metal-oxide-semiconductor.The N pipe is clamped, is applicable to high-voltage applications.
It should be noted that, the clamped switching tube Q4 of described active clamped normal shock module is just contrary with conducting and the cut-off state of main switch Q5; Clamped switching tube Q4 is consistent with conducting and the cut-off state of continued flow tube Q7; Main switch Q5 is consistent with conducting and the cut-off state of forward switching tube Q6.
Below illustrate for example the operation principle of active clamped normal shock module 103:
400V direct voltage by after boosting, be converted to the 24V direct voltage output.Active clamped normal shock module is a kind of of forward converter, from traditional normal shock, utilize the winding reset mode different, active clamped normal shock module adopts the resonant reset mode, realize the lossless reset of transformer, can realize the low-voltage conducting (VVS) of main switch Q5 simultaneously, and the no-voltage conducting (ZVS) of clamped switching tube Q4.The advantage of normal shock is to have lower output voltage ripple and current ripples, has good intermodulation performance and dynamic load, be well suited for multichannel output, and the mode of employing resonant reset can effectively reduce the EMC of converter.The active clamped transformer voltage waveform that approaches square wave that has, be suitable for self-device synchronous rectification, referring to Fig. 2.
Wherein, clamped capacitor C 3 and clamped switching tube Q4 form the clamped structure of normal shock module, drive signal Drv2 and Drv3 single spin-echo; Forward switching tube Q6 and continued flow tube Q7 form output synchronous rectification structure.The key of circuit design is exactly that the parameter of transformer T1 and clamped capacitor C 3 is selected, and drives signal Drv2 and the anti-phase setting of Drv3, dead band time setting between the two.
For active clamped normal shock module, worst state appears at starting with full load and fully loaded off state, adopt Master control chip, soft start/the turn-off function carried as NCP1562, can improve significantly startability, in order to guarantee the reliability of soft shutoff, to the VCC of NCP1562, power supply seals in the first voltage-stabiliser tube ZD1, guarantees that the driving turn-off time of Master control chip is early than the power down time that drives chip.Master control chip drives to close and has no progeny, and drives chip to turn-off, and clamped capacitor C 3 is clamped firmly by the remanent magnetism of normal shock transformer, prevents remanent magnetism and the vibration of clamped switching tube Q4 parasitic capacitance, and over-voltage breakdown main switch Q5, referring to Fig. 3.
It should be noted that, described driver module 104 comprises: former limit driver element 1041 and secondary synchronous rectification driver element 1042;
Described former limit driver element 1041, for generation of the control signal DRV2 of clamped switching tube Q4 and the control signal DRV3 of main switch Q5;
Described secondary synchronous rectification driver element 1042, for generation of the control signal DRV5 of continued flow tube Q7 and the control signal DRV4 of forward switching tube Q6.
Referring to Fig. 3, as an embodiment, described former limit driver element 1041 comprises: Master control chip, driving chip;
Described Master control chip, as the first output pin out1 of NCP1562 directly receives the driving chip, as the second input pin IN_LO of NCP518; The second output pin out2 of Master control chip receives the first input pin IN_HI that drives chip by inverter;
The first output pin DRV_HI of described driving chip receives the control signal DRV2 of clamped switching tube Q4 by the homophase driver for isolating; The second output pin DRV_LO of driving chip directly receives the control signal DRV3 of main switch Q5;
Described inverter, comprise the 8th metal-oxide-semiconductor Q8, and its grid is connected with the second output pin out2 of Master control chip by the 8th resistance R 8, and its grid is by the tenth resistance R 10 all ground connection that is connected with its source class also; Its drain electrode is connected with direct voltage VCC by the 7th resistance R 7, and the first input pin that drives chip is received in its drain electrode;
Described homophase driver for isolating comprises: the winding A series connection of the 15 resistance R 15, the tenth capacitor C 10 and transformer T2, the first output pin DRV_HI of the described driving chip of another termination of the 15 resistance R 15, different name end 2 ground connection of winding A; The winding B of the 9th capacitor C the 9, the 14 resistance R 14, transformer T2, the second Zener diode ZD2 series connection are a loop, and the common port that the second Zener diode ZD2 is connected with the 9th capacitor C 9 is received the control signal DRV2 of clamped switching tube Q4.
Below illustrate for example the operation principle of former limit driver element 1041:
Active clamped normal shock module requires its clamped switching tube Q4, main switch Q5 to drive and adopts anti-phase type of drive.So the second output pin Out2 at Master control chip has added inverter, realized the second output pin Out2 and the first output pin Out1 single spin-echo of Master control chip.PWM that Out1 and Out2 are Master control chip output, Out1 is with Out2 for synchronizeing output, so Out2 need to increase the inverter consisted of R7, R8, R10 and the 8th metal-oxide-semiconductor Q8.
Traditional type of drive comprises: transformer isolation drives, chip boot drives.Referring to Fig. 3, the control signal DRV2 of the clamped switching tube Q4 exported with the homophase driver for isolating, can prevent that main switch Q5 fast conducting is too high with the clamped switching tube Q4 grid voltage that shutoff causes, damages and drive chip, improved the reliability of circuit.Transformer isolation drives and comprises: driven in phase and anti-phase driving, because active clamped in soft start/shutoff, the change in duty cycle scope is large, during with anti-phase driving, driving voltage can have a greater change, and easily causes the problem of driving force deficiency, therefore selects driven in phase.
The homophase driver for isolating consisted of R14, R15 and C9, C10, T2, ZD2, be suspended in the clamped switching tube Q4 of high-pressure side for driving, with respect to chip drives, transformer drives and do not have the negative pressure that high-pressure side produces and damage impact.
As an embodiment, described secondary synchronous rectification driver element 1042 comprises: anti-phase self-driven device and the self-driven device of homophase;
Referring to Fig. 4 a, described anti-phase self-driven device, comprise: the first driver, the 3rd Zener diode ZD3 and the winding C anti-phase with the winding B of transformer T1, the first end of the first driver connects the anode of the 3rd Zener diode ZD3, the negative electrode of the 3rd Zener diode ZD3 connects the different name end 6 of winding C, the Same Name of Ends 5 of winding C connects the second end of the first drivers ground connection all, the control signal DRV5 of the 3rd termination continued flow tube Q7 of the first driver;
Referring to Fig. 4 a, described the first driver, comprise the 9th triode Q9, and its emitter connects the 3rd end of the first driver, and its base stage connects the first end of the first driver by the 17 resistance R 17, second end of its collector electrode driver connected 1; Between the first end of the first driver and the 3rd end, connected the 16 resistance R 16 and the 7th diode D7, in parallel the 4th Zener diode ZD4, the 18 resistance R 18 and the 11 capacitor C 11 between the 3rd end of the first driver and the second end.
Referring to Fig. 4 b, the self-driven device of described homophase, comprise: the second driver and with the winding D of the winding B homophase of transformer T1, the first end of the second driver connects the Same Name of Ends 7 of winding D, the different name end 8 of winding D connects the second end of the second drivers ground connection all, the control signal DRV4 of the 3rd termination forward switching tube Q6 of the second driver;
The second driver of the self-driven device of described homophase and the first driver circuit structure of described anti-phase self-driven device are identical.The structure of the self-driven implement body of described homophase comprises: the Same Name of Ends 7 of the winding D of transformer T1 is connected with an end of the 20 resistance R 20, the other end of the 20 resistance R 20 is connected with the base stage of the tenth triode Q10, the Same Name of Ends 7 of the winding D of transformer T1 is connected with an end of the 19 resistance R 19, the other end of the 19 resistance R 19 is connected with the sun level of the tenth diode D10, the cathode of the tenth diode D10 is connected with the emitter of the tenth triode Q10, the emitter of the tenth triode Q10 is as the control signal DRV4 of forward switching tube Q6, the collector electrode of the tenth triode Q10 is connected with the different name end 8 of the winding D of transformer T1, and ground connection all, be parallel with the 5th Zener diode ZD5 between the emitter of the tenth triode Q10 and collector electrode, the 21 resistance R 21 and the 12 capacitor C 12.
Below illustrate for example the operation principle of secondary synchronous rectification driver element 1042:
Active clamped normal shock transformer T1 waveform approaches square wave, because a little output is applicable to adopting self-device synchronous rectification.Transformer has following 2 requirements to secondary synchronous rectification driver element: 1, when underloading, the continued flow tube Q7 of synchronous rectification does not work, during underloading, output current is discontinuous mode, if continued flow tube Q7 work, the easy generation current of outputting inductance pours in down a chimney, gently cause inefficiency, heavy can burn out the synchronous rectification unit; 2, when continued flow tube Q7 works, require the necessary reliable turn-off of forward switching tube Q6, and maintain off state, pour in down a chimney go back to loop, former limit (the winding A of T1) to prevent output current, referring to Fig. 4, Fig. 5.
Wherein, the winding C of transformer T1 and winding D are respectively used to drive continued flow tube Q7 and forward switching tube Q6.Electric current pours in down a chimney when preventing underloading, at a voltage-stabiliser tube ZD3 of the winding C of transformer T1 series connection, when underloading, tertiary winding voltage is very low, be no more than the Zener voltage of voltage-stabiliser tube ZD3, continued flow tube Q7 can't reach conducting voltage, the problem that while therefore not having underloading, the second inductance L 2 electric currents pour in down a chimney.
Referring to Fig. 4, in driver, by D7 and Q9, form reverse restore circuit, for the continued flow tube Q7 gate charge of releasing, the 17 resistance R 17, for current limliting, prevents from driving winding current to pour in down a chimney.The adjustable delay start-up circuit formed by the 16 resistance R 16 and the 11 capacitor C 11.
Winding C and the winding D of transformer T1 are anti-phase, wherein comprised driver functions identical.
Referring to Fig. 5, it should be noted that, described active clamped normal shock module also comprises saturable reactor L3, is serially connected between the in-phase end 3 and the second inductance L 2 of winding B of transformer T1.
As an embodiment, when forward switching tube Q6 conducting, L3 is saturated for the saturable reactor, is similar to short circuit.There is one no-voltage period in the winding B of transformer T1 in Dead Time, now transformer T1 leakage inductance and secondary parasitic capacitance resonance, can between the drain-source of continued flow tube Q7, form very large voltage and current spike, add saturable reactor L3, amplitude and the energy that can suppress spike, and, in forward switching tube Q6 and continued flow tube Q7 switching process, reducing the di/dt of switching tube, the EMC that suppresses power supply disturbs.
The direct current of BUCK module: 24V is divided into multichannel output after the step-down of BUCK module.Because the operating frequency of active clamped normal shock module is 100K, and the signals collecting bandwidth of cellanalyzer is 1K-150K, the operating frequency of active clamped normal shock module, in the signals collecting part bandwidth range of cellanalyzer, easily partly produces interference to signals collecting; The operating frequency of BUCK module is 500K, and through the BUCK module, the ripple of 100KHz is inhibited.The voltage reduction module of multichannel also makes complete machine have good intermodulation performance and dynamic load ability simultaneously.The design main points of BUCK module are that operating frequency is arranged on outside the signals collecting part bandwidth range of cellanalyzer, as are designed to 500K.
In sum, beneficial effect of the present invention is as follows:
1, adopt active clamped normal shock module, power supply is optimized, make its soft start/shutoff waveform more desirable;
2, the processing mode of driver module, as adopted inverter and homophase driver for isolating, both increased reliability, can regulate more easily Dead Time again, for the soft switch performance of optimizing product, has very great help;
3, add saturable reactor L3 in active clamped normal shock module, the operating state of optimized synchronization rectification, prevent continued flow tube Q7 electric current and pour in down a chimney, and suppresses continued flow tube Q7 due to voltage spikes;
4, add the output of BUCK module multichannel, (500K) is higher for operating frequency, has suppressed intermediate frequency, the low-frequency disturbance of power supply, and the normal shock module is disturbed power supply and divided bandwidth range away from the cellanalyzer signal amplifying part than the interference of the ripple of low frequency (100K).
The above change-over circuit of the isolation to a kind of power supply provided by the present invention is described in detail, for one of ordinary skill in the art, thought according to the embodiment of the present invention, all will change in specific embodiments and applications, in sum, this description should not be construed as limitation of the present invention.