CN2710247Y - High-efficient switch circuit for non-linear load - Google Patents
High-efficient switch circuit for non-linear load Download PDFInfo
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- CN2710247Y CN2710247Y CN 200420001507 CN200420001507U CN2710247Y CN 2710247 Y CN2710247 Y CN 2710247Y CN 200420001507 CN200420001507 CN 200420001507 CN 200420001507 U CN200420001507 U CN 200420001507U CN 2710247 Y CN2710247 Y CN 2710247Y
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Abstract
The utility model provides a power switch circuit for cold cathode fluorescence lamp (CCFL) using a high-efficient no-voltage switch technique to eliminate the switch loss of the horsepower MOSFET. Taking the parasitic capacitance in the resonance circuit into consideration, the utility model applies an optimal sweep frequency technique to the lighting of CCFL. Moreover, the power switch circuit for CCFT which is the self-adapting type can decide the optimal operating frequency of the circuit with given load. The utility model also provides an over-voltage protection circuit to protect the circuit element under the open-circuit condition of the CCFL.
Description
Technical field
The utility model relates to a kind of AC/DC power converter circuit.In particular, the utility model provides a kind of efficient controller circuitry, and this controller circuitry adopts a kind of zero voltage switching technology to adjust the power that is delivered to load.The utility model generally is used to drive the circuit of one or more cold-cathode fluorescence lamps (CCFL), and still, those skilled in the art can learn that the utility model can be used for any load that requires high efficiency and the control of accurate power.
Background technology
Figure 1 shows that a kind of traditional C CFL power-supply system 10.This system comprises the CCFL in a power supply 12, CCFL drive circuit 16, controller 14, feedback control loop 18 and the one or more LCD screen 20 substantially.Power supply 12 provides a direct voltage to circuit 16, and controls by transistor Q3 controlled device 14.Circuit 16 is a self-resonance circuit, such as Roy's circuit (Royer circuit).In fact, circuit 16 is a self-oscillation AC/DC converter, and its resonance frequency is by L1 and C1 decision, the number of turn of N1 to N4 indication transformer coil and coil.At work, alternately conducting and the input voltage on switching coil N1 and the N2 respectively of transistor Q1 and Q2.If the Q1 conducting, then input voltage places on the coil N1.Voltage with relative polarity will place on other the coil.Induced voltage among the N4 makes the base stage of Q2 for just, and Q1 conducting by the very little voltage drop between collector and emitter.The induced voltage of N4 also makes Q2 remain on cut-off state.The Q1 conducting is till the magnetic flux in the TX1 iron core reaches capacity.
When saturated, the collector voltage fast rise of Q1 (reaching) by value that base circuit determined, and the induced voltage in the transformer descends fast.Q1 is unsaturated by saturated trend, and V
CERise, cause the voltage on the N1 further to descend.Loss in the base drive causes Q1 to end, and it causes again that subsequently the magnetic flux in the iron core descends slightly, thereby and in N4 induction produce an electric current and make the Q2 conducting.It is in the opposite direction saturated up to iron core that induced voltage among the N4 makes Q1 remain on the saturation conduction state, then produces a similar inverse process, switches circulation thereby finish.
Although inverter circuit 16 is made of fewer element, its operate as normal must depend on the nonlinear interaction of the complexity of transistor and transformer.In addition, C1, the variation of Q1 and Q2 (being generally 35% tolerance) will make circuit 16 not be suitable for the shunt transformer configuration, because any duplicating of circuit 16 all can produce extra undesirable operating frequency, this frequency may be at some harmonic wave place resonance.When being applied to the CCFL load, this circuit can produce significantly undesirable " flapping " effect in CCFL.Even if tolerance is almost mated, but because circuit 16 work in the self-resonance pattern, so the effect of flapping can not eliminate because any duplicating of circuit all will have itself distinctive operating frequency.
At United States Patent (USP) 5,430, can find some other drive system in 641,5,619,402,5,615,093,5,818,172.These inventions have that efficient is low, two steps power transfer, frequency conversion operation and/or the shortcoming of correlation is arranged with load.In addition, when load comprises CCFL and assembly, the parasitic capacitance of the impedance of the CCFL that can exert an influence itself.In order effectively to design a kind of circuit of energy operate as normal, must consider the spurious impedance that is used to drive the CCFL load when designing this circuit.But such design is not only time-consuming, expensive, and is difficult to obtain one and can handles unequally loaded best converter design.Therefore need overcome these shortcomings and a kind of circuit solution is provided, this circuit have the efficient height, reliably CCFL light, with the irrelevant power adjustment of load and the characteristics of single-frequency power transfer.
Therefore, the utility model provides a kind of optimizer system that is used for driving load, and it has realized the best effort of various LCD screen load, thereby has improved the reliability of system.
The utility model content
In a broad sense, the utility model provides a kind of AC/DC converter circuit, is used for controllably power being sent to load, and it comprises an input voltage; More than first overlapping switches and more than second overlapping switches of linking to each other with this voltage selectivity, these more than first overlapping switches define first guiding path, and these more than second overlapping switches define second guiding path.A pulse generator that is used for producing a pulse signal.A drive circuit that receives this pulse signal and control the conducting state of these more than first and second switches.Transformer with primary coil and secondary coil, this primary coil optionally are connected to this voltage by first guiding path or second guiding path in an alternating manner.A load that links to each other with the secondary coil of transformer.Feedback control loop between load and drive circuit, this feedback circuit provide the feedback signal of the power of expression supply load.This drive circuit makes first and second a plurality of switches be in the alternate conduction state, and switch overlapping time in the overlapping time of the switch in more than first switch and more than second switch by turns, thereby based on feedback signal and pulse signal voltage is connected to primary coil to small part.
This drive circuit can produce one first complementary pulse signal and a ramp signal by pulse signal.This pulse signal offers first switch of this more than first switch, thereby control its conducting state, thereby this ramp signal is compared with this feedback signal at least and is produced one second pulse signal, and one of them may command conducting overlap condition is present between the conducting state of first switch of more than first switch and second switch.This second pulse signal offers second switch of more than first switch and controls its conducting state.This drive circuit also produces one second complementary pulse signal according to this second pulse signal, and wherein the first and second complementary pulse signals are controlled the conducting state of first and second switches of more than second switch respectively.Similarly, may command conducting overlap condition also is present between the conducting state of first and second switch of more than second switch.
In first embodiment, the utility model provides one to be used for the converter circuit of delivering power to a CCFL load, it comprises a voltage, transformer with primary coil and secondary coil, define first pair of switch and the second pair of switch of first and second guiding paths between voltage and the primary coil respectively, a CCFL load circuit that links to each other with secondary coil, a pulse generator that produces pulse signal, the feedback circuit of the feedback signal that links to each other with this load and produce, a drive circuit that receives this pulse signal and feedback signal, and this drive circuit is connected first pair of switch to voltage and primary coil according to this pulse signal with feedback signal, thereby delivering power is given this CCFL load.
In addition, first embodiment also provides a generation to have the pulse generator of the pulse signal of the frequency of preestablishing.This drive circuit comprises first, second, third and the moving circuit of 4 wheel driven; This first pair of switch comprises first and second transistors; Second pair of switch comprises third and fourth transistor.This first, second, third and the moving circuit of 4 wheel driven be connected to the first, second, third and the 4th transistorized control line respectively.This pulse signal offers this first drive circuit, makes the first transistor according to this pulse signal conducting or end.The 3rd drive circuit produces the first complementary pulse signal and a ramp signal based on this pulse signal, and this first complementary pulse signal is offered the 3rd transistor, makes the 3rd transistor according to this first complementary pulse signal and conducting or end.This ramp signal is compared with feedback signal, produce second pulse signal.This second pulse signal offers second drive circuit, makes this transistor seconds according to this second pulse signal conducting or end.The moving circuit of 4 wheel driven produces one second complementary pulse signal based on second pulse signal, and this second complementary pulse signal is offered the 4th transistor, makes the 4th transistor according to this second complementary pulse signal conducting or end.In the utility model, the power total amount that is sent to load has been controlled in the conducting and the 3rd simultaneously of first, second transistor, the conducting simultaneously of the 4th transistor.This pulse signal and second pulse signal be overlaid by a controllable amounts control, thereby gives load along the first guiding path transmission power.Because the first and second complementary pulse signals are produced by the pulse signal and second pulse signal respectively, so first and second the complementary pulse signal that produces is the overlaid by a controllable amounts control also, power is along second guiding path, and sends load to according to the mode that replaces between first and second guiding paths.
In addition, the phase difference between this pulse signal and the first complementary pulse signal is about 180 degree, and this second pulse signal and second complementary signal differ and also be approximately 180 degree, thereby has avoided the short-circuit condition between first and second guiding path.
The converter circuit that in first embodiment, provides, second embodiment comprises a flip-flop circuit that is connected with this second pulse signal, have only when the 3rd transistor switches to conducting state, it is second drive signal that this flip-flop circuit could trigger this second pulse signal.In addition, second embodiment comprises a phase-locked loop (PLL) circuit, and this circuit has one from first input signal of primary coil and second input signal of the described feedback signal of employing.Differing between these two signals of PLL circuit comparison, and provide a control signal to pulse generator, thereby based on the pulsewidth that differs this pulse signal of control between first and second input.
In these two embodiment, preferred circuit all comprises the feedback control loop with one first comparator, produces one first output signal thereby this first comparator is used for comparison reference signal and feedback signal.This feedback control loop also provides one second comparator, and this second comparator is used for relatively this first output signal and ramp signal, and produces this second pulse signal based on the intersection point of first output signal and ramp signal.This feedback circuit preferably comprises a current detection circuit and the switching circuit between first and second comparators again, this current detection circuit receiving feedback signals and produce a triggering signal wherein, this switching circuit receives this flop signal, and, produce one first output signal or predefined minimum signal based on the value of this flop signal.This reference signal for example can comprise, expression is sent to the signal of artificial generation of the expectation power of described load.This predefined minimum voltage signal can comprise the minimum voltage of having programmed of a supply switch, makes overvoltage condition can not occur in the load.
Similarly, among two embodiment described here, all can provide a circuit overcurrent protection, this circuit receiving feedback signals and based on the value clamp-pulse generator of this feedback signal; An excess voltage protection can also be provided; this overvoltage crowbar is used for receiving the voltage signal and first output signal in the load; and the voltage signal of relatively this load and first output signal, thereby come clamp-pulse generator based on the voltage signal values in the load.
Description of drawings
Figure 1 shows that a kind of traditional AC/DC converter circuit;
Figure 2 shows that a preferred embodiment of AC/DC converter circuit of the present utility model;
Fig. 2 a-2f is depicted as the typical sequential chart of circuit among Fig. 2;
Figure 3 shows that another preferred embodiment of AC/DC converter circuit of the present utility model;
Fig. 3 a-3f is depicted as the typical sequential chart of circuit among Fig. 3; With
Fig. 4 a-4f is depicted as the analogous diagram of Fig. 2 and circuit shown in Figure 3.
Embodiment
Although do not wish to be limited by example, following detailed description will be described as the load of the utility model circuit with reference to the CCFL screen.But obviously, the utility model is not limited to only drive one or more CCFL, and on the contrary, the utility model should be interpreted as a kind of power converter circuit that is not used for the certain loads restriction of application-specific widely.
Generally speaking, the utility model provides a kind of closing time of utilizing feedback signal and pulse signal to adjust two pairs of switches (ON time), thereby controllably power is sent to the circuit of load.When pair of switches by controllable closure, make that its closing time is overlapping, power is just along by this defined guiding path of switch (by a transformer) being transferred into load.Equally, when another to switch by controllably closed and when making that its closing time is overlapping, power is transferred into load along this another to the defined guiding path of switch (by a transformer).Therefore, by the overlapping closing time between Closing Switch and control switch optionally, the utility model can accurately be controlled and send a power of giving fixed load to.In addition, the utility model also comprises overcurrent and excess voltage protection, when circuit is under short circuit or the open-circuit condition, can end the power of load is transmitted.And control switch topological structure described herein makes the work of circuit not be subjected to load limitations, and works in the one working frequency that a resonance effect that is not subjected to transformer configuration influences, and these characteristics are discussed following with reference to the accompanying drawings.
Circuit block diagram shown in Figure 2 is the preferred embodiment of phase shift of the present utility model, full-bridge, zero voltage switching power converter.Usually, circuit shown in Figure 2 comprises: a power supply 12; A plurality of switches 80, described switch definition alternate conduction path and to be arranged as the switch of diagonal form right; Be used for driving the drive circuit 50 of each switch; One produces the frescan 22 that square-wave pulse is given drive circuit 50; A transformer TX1 (having primary coil and the defined relevant resonance circuit of C1) by TX1; With a load.Advantage of the present utility model is that it has also comprised an overlapping feedback control loop 40, and each allows controllable power to be sent to load to the closing time of switch thus at least in its control.
Although do not wish to be limited to by the example among this embodiment, drive circuit B (B_Drive) preferably is made of totem-pote circuit, general Low ESR operation amplifier circuit or emitter-base bandgap grading following device circuit.Drive circuit C (C_Drive) also adopts same structure.Because the not direct ground connection (being unsteady) of drive circuit A (A_Drive) and drive circuit D (D_Drive), so these two drive circuits preferably are made of boot-strap circuit (boot_strap circuit) or other high side (high-side) drive circuit as known in the art.In addition, as mentioned above, drive circuit A (A_Drive) and drive circuit D (D_Drive) comprise an inverter, with respectively oppositely from the signal (for example phase place) of drive circuit B (B_Drive) and drive circuit C (C_Drive).
Efficient operation is finished by the zero voltage switching technology.Four MOSFET (Switch_A to Switch_D) 80 conducting after its intrinsic diode (D1-D4) conducting, it provides the current flow path of the power in transformer/capacitor (TX1/C1) configuration, and the voltage at their two ends when therefore guaranteeing these switch conductions is zero.By this in check work, to make switch cost be minimum and keep high efficiency.
The preferable switch operating of overlapping switch 80 please refer to the sequential chart of Fig. 2 a-2f.Switch C disconnects (Fig. 2 f) in certain period of switch B and the equal conducting of C.Behind the cut-off switch C, the electric current (with reference to figure 2) that flows in the resonant circuit flow through diode D4 (Fig. 2 e figure), primary coil, C1 and the switch B of transformer among the switch D, thereby make the voltage and current of capacitor C 1 and transformer produce resonance, the delivering power when result makes switch B and C conducting (Fig. 2 f).It should be noted that above-mentioned state to occur, because the sudden change of the sense of current of transformer will be violated Faraday's law.Therefore, when switch C disconnects, the electric current D4 that flows through must be arranged.After the D4 conducting, switch D is closed.Equally, switch B disconnects (Fig. 2 a), the diode D1 of (Fig. 2 e) current direction switch A before the switch A closure.Equally, switch D disconnects (Fig. 2 d), and electric current is by switch A flow through C1, transformer and diode D3.(Fig. 2 e) switch C is closed after the D3 conducting.It is closed that switch B disconnects the back in switch A, and this makes diode D2 at first be switched on before switch B closure.It should be noted that the overlapping decision of the closing time that is diagonal angle linear switch B, C and A, D is sent to the power of transformer, shown in Fig. 2 f.
In this embodiment, Fig. 2 b is depicted as and only produces ramp signal 26 when switch A is closed.Therefore, the drive circuit A that produces this ramp signal 26 preferably includes a constant current generator circuit (not shown), and it comprises that the electric capacity with appropriate time constant produces ramp signal.For this purpose, utilize a reference current (not shown) to give this electric capacity charging, and this electric capacity is grounded (for example by a transistor switch), makes its discharge rate exceed charge rate, thereby produce a sawtooth ramp signal 26.Certainly, as mentioned above, this can realize that also therefore, ramp signal 26 can also produce with an integrating circuit (for example operational amplifier and electric capacity) by the integration of pulse signals 90.
Between burn period, be predefined minimum overlay of (for example between switch A, D and B, C) generation between the linear switch in diagonal angle at two.Thereby provide a minimum power to a resonant circuit and a CCFL load that comprises C1, voltage device, C2, C3 by input.It should be noted that load can be ohmic and/or capacitive.Driving frequency starts from a predefined upper frequency, up to it near resonant circuit with by the resonance frequency of the equivalent electric circuit of the secondary coil of transformer performance.Considerable power is sent to the CCFL load.Because prefiring high impedance feature, CCFL is subjected to the high-tension influence from the power of supplying with primary coil.This voltage is enough to light CCFL.The CCFL impedance drop is low to moderate its normal working value (for example about 100K ohm is to 130K ohm), and no longer is enough to keep the steady operation of CCFL based on the power of the supply primary coil of minimum overlay work.The output of error amplifier 32 begins its regulatory function, thereby increases lap, i.e. the level decision lap of error amplifier output.For example:
For this purpose, error amplifier 32 compares feedback signal FB and a reference voltage REF.FB is the current value appraisal of flowing through and detecting resistance R s, and its expression is via the total current of load 20.REF represents to expect load condition, for example the flow through current signal of this load of expectation.In normal work period, REF=FB.Yet if load condition is compensated by the dim switch of a LCD display wittingly, REF value is understood correspondingly increase/reduction.This value that is compared correspondingly produces CMP.CMP value reaction load state and/or one is bias voltage intentionally, and is realized by the difference between REF and FB (being REF-FB).
In order to prevent to be in open-circuit condition (for example in operate as normal time open circuit CCFL lamp state) at the load of load-side and circuit, preferably also that a FB signal and a reference value is (not shown, and different with above-mentioned REF signal) in current sense comparator 42, to compare, it exports the state of definition switch 28 as described below.This reference value can be programmable, and/or is user-defined, and the minimum or the maximum current (for example, can specifiedly be used for individual elements, especially for the CCFL load) that preferably reflect system and allowed.If the value (operate as normal) in allowed band of feedback FB signal and reference signal, then current sense comparator is output as 1 (or high level).This allows the CMP switch 38 of flowing through, and circuit is worked saidly, comes delivering power to load.Yet, if the value of FB signal and reference signal (open circuit or short-circuit condition) outside predefined scope, current sense comparator be output as 0 (or low level), thereby forbid that the CMP signal flow is through switch 38.(certainly, can realize inverse process, wherein switch triggers at 0 state).Up to current sense comparator represent to allow the to flow through electric current of Rs, just minimum voltage Vmin is provided and provides it to comparator 28 by switch 38 (not shown).Correspondingly, switch 38 comprises and being used for when the detection electric current is 0, to the suitable programmable voltage selection of Vmin.Refer again to Fig. 2 b, the effect of this work is to make the CMP D. C. value be reduced to rated value, and perhaps minimum value (being CMP=Vmin) makes high-voltage state can not occur on transformer TX1.Therefore, intersection point 36 is by to moving to left, thereby reduced the lap between complementary switch (remembeing at the intersection point 36 switch C of place for closed).Equally, when detected value is 0 (the perhaps preset value of other expression open-circuit condition), current sense comparator 42 is connected to frequency generator 22, closes generator 22.CMP is fed to protective circuit 62.This is to say when CCFL is removed at work (open-circuit condition), and frescan 22 cuts out.
In order to prevent that overvoltage condition from appearring in circuit, present embodiment preferably includes a protective circuit 60, below provides its work work (overcurrent protection of current sense comparator 42 was set forth above-mentioned).Circuit 60 comprises a protection comparator 62, and this protection comparator is compared signal CMP with a voltage signal 66 that is obtained by load 20.Preferably voltage signal 66 is obtained by as shown in Figure 2 dividing potential drop capacitor C 2 and C3 (in parallel with load 20).Under the CCFL open-circuit condition, frescan continues frequency sweep, reaches a threshold value up to OVP signal 66.OVP signal 66 is taken from the dividing potential drop capacitor C 2 and the C3 of output, thereby detects the voltage of transformer TX1 output.For simplifying the analysis, these electric capacity are also represented the total capacitance of equivalent load capacitance.This threshold value is a reference value, and the voltage that this protective circuit 60 is designed to guarantee the transformer secondary output coil is greater than minimum ignition voltage (for example shielding needed voltage by LCD) and less than the rated voltage of transformer.When OVP66 exceeded this threshold value, frescan stopped frequency sweep.Simultaneously, current sense comparator 42 detects less than signal on detection resistance R s.Therefore, in the output of switch module 38, promptly 24 signals are set to minimum value, make that the lap between switch A, C and B, D is minimum.In case when OVP exceeds threshold value, preferably start timer 64 immediately, thereby start a string overtime (time-out) sequence.The duration of this overtime sequence is preferably designed according to load request (for example CCFL of LCD screen), but also can be set at programmable value.In case timing time finishes, driving pulse is invalid, thereby the trouble free service output of converter circuit is provided.In other words, circuit 60 provides a sufficient voltage to light fluorescent tube, but if this lamp does not link to each other with transducer, then will be closed after a period of time, thereby avoid at the output error high pressure.The duration of this overtime sequence is essential, because the lamp ﹠ lantern of not lighting is similar to the CCFL open-circuit condition.
Fig. 3 and 3a-3f are depicted as another preferred embodiment of AC/DC circuit of the present utility model.In this embodiment, this circuit is worked to be similar to the mode shown in Fig. 2 and the 2a-2f, yet this embodiment also comprises a flip-flop circuit 72 that is used for controlling 70 and timing input signals of phase-locked loop circuit (PLL) of frescan 22 to the C drive circuit.Shown in sequential chart,, just can realize the increase of lap between switch A, D and B, C, thereby increase the power that is delivered to transformer if, the driving pulse of 50% duty ratio of switch C and D is moved to right by increasing the level of CMP.In fact, this just belongs to the high current work state of fluorescent tube (can realize by artificial increase REF voltage as mentioned above).On the contrary, the driving pulse of switch C and D is moved to left (by reducing the CMP signal), then reduced the power that is transmitted.The phase relation of phase-locked loop circuit 70 between normal work period maintenance feedback current (through Rs) and resonance circuital current (through TX1/C1), as shown in Figure 3.PLL circuit 70 preferably includes from the input signal 98 of resonant circuit (C1 and TX1 primary coil) and the feedback signal on the Rs (above-mentioned FB signal).In case CCFL is lighted and Rs detects electric current among the CCFL, PLL 70 circuit just are activated, the phase place between the electric current in this a circuit locking CCFL lamp current and the resonant circuit (C1 and transformer).In other words, PLL is used for adjusting the frequency of frescan 22, because change the frequency that can influence frescan as the parasitism of temperature action, mechanical arrangements, for example wiring between transducer and LCD screen and influence capacitance and the lamp of inductance value and LCD shield distance between metal frame of this mechanical arrangements.It is 180 degree that this system preferably keeps differing between the electric current of resonant circuit and the Rs that flows through (load current).Therefore, no matter the specific load state and/or the operating frequency of resonant circuit, this system can find a best operating point.
The operation class of feedback loop shown in Figure 3 is similar to the explanation among above-mentioned Fig. 2.Yet shown in Fig. 3 b, this embodiment is by 72 pairs of output timing via the initialize signal of C drive circuit of trigger.For example, when operate as normal, the output of error amplifier 32 is fed through control switch module 38 (as mentioned above), obtains signal 24.Obtain certain lap between switch A, D and B, C by comparator 28 and trigger 72, this trigger 72 driving switch C and D (remembeing that the D drive circuit produces the complementary signal of C drive circuit).This is that CCFL (screen) load provides steady operation.CCFL (screen) is removed in consideration when operate as normal, CMP is raised to the boundary value (rail of output) of error amplifier output and trigger protection circuit immediately.This function is under an embargo when lighting fluorescent tube.
With reference to Fig. 3 a-3f, in the present embodiment, be working result by flip-flop circuit 72 via C drive circuit and D drive circuit trigger switch C and D.Shown in Fig. 3 b, trigger is every once triggering, thereby initialization C drive circuit (and correspondingly, initialization D drive circuit).Sequential please refer to Fig. 2 a-2f then with same way as work as the aforementioned.
Fig. 4 a-4f is depicted as the analogous diagram of the output circuit of Fig. 2 or Fig. 3.For example, Fig. 4 a is shown in 21 volts of whens input, and when frescan during near 75.7K hertz (0.5 microsecond is overlapping), output reaches 1.67KV
P-pOutput is if CCFL needs 3300V
P-pIgniting, then this undertension is to light CCFL.When frequency was reduced to such as the 68K hertz, minimum overlay produced about 3.9KV in output
P-p, this is enough to light CCFL, as shown in Fig. 4 b.Shown in Fig. 4 C, in this frequency, lap increases to 1.5 microseconds, makes to export about 1.9KV
P-p, make the lamp impedance work of 130K ohm.In another example, Fig. 4 d is depicted as the work when input voltage is 7 volts.When the 71.4K hertz, before CCFL is lighted, be output as 750Vp-p.When frequency reduced, output voltage just increased, till CCFL lights.Fig. 4 e is depicted as when the 65.8K hertz, and output reaches 3500V
P-pThe adjusting of CCFL electric current is finished by regulating lap, thereby keeps the work of the impedance of 130K ohm afterwards in igniting.This moment is for 660V
RmsLamp, the voltage at CCFL two ends is 1.9KV
P-pShown in Fig. 4 f.Though do not narrate at this, the simulation result of Fig. 3 circuit is a similar fashion.
Difference (promptly increasing trigger and PLL in Fig. 3) that it should be noted that first and second embodiment will can not influence in the overall work parameter shown in Fig. 4 a-4f.Yet it is the imperfect impedance of considering in the circuit that decision increases PLL, and can be used as the replacement circuit of circuit shown in Fig. 2 and add.Simultaneously, increase trigger and allow to remove above-mentioned constant current circuit.
Therefore, the utility model provides a kind of efficient self-adapted AC/DC converter circuit obviously, the target that it is satisfied with here to be proposed.For a person skilled in the art, some possible modifications are conspicuous.For example, use MOSFET as switch though the utility model has been described, those skilled in the art can know that entire circuit can use the BJT transistor, or the transistorized combination of any type, comprise that MOSFET and BJT construct.Other modification also is possible.For example related with drive circuit B and drive circuit D drive circuit can be made up of common-collector circuit, because therefore the transistor ground connection that is associated floating state can't occur.PLL circuit described here is preferably general PLL circuit 70 known in the art, through suitably revising, can accept input signal as mentioned above and produce control signal.Pulse generator 22 is preferably pulse-width modulation circuit well known in the art (PWM) or frequency range modulation circuit (FWM).Equally, protective circuit 62 and timer come work by known circuit formation and suitable correct.
Claims (20)
1. one kind is used for controllable delivering power and gives the AC/DC converter circuit of load, it is characterized in that this AC/DC converter circuit comprises:
The a plurality of switches that link to each other with a voltage selectivity;
Be used for controlling the drive circuit of described a plurality of switch conduction states;
The transformer that a primary coil and secondary coil are arranged, described primary coil links to each other with described voltage in an alternating manner; With
Feedback loop circuit between described load and described drive circuit, described feedback loop circuit provide an expression to supply with the feedback signal of the power of described load.
2. AC/DC converter circuit according to claim 1 is characterized in that when described feedback signal surpasses a predefined scope, described drive circuit control switch conducting state, thus reduce power to the first level of described load.
3. AC/DC converter circuit according to claim 2 is characterized in that described a plurality of switch is overlapping switch.
4. AC/DC converter circuit according to claim 3, it is characterized in that this circuit also comprises more than second overlapping switch, wherein said more than first switch optionally links to each other with described voltage with described more than second switch, and described more than first overlapping switches define first guiding path, and described more than second overlapping switches define second guiding path.
5. AC/DC converter circuit according to claim 2 is characterized in that described first level is zero.
6. AC/DC converter circuit according to claim 2, it is characterized in that described first level be one greater than zero value.
7. AC/DC converter circuit according to claim 2 is characterized in that described feedback signal is the flow through signal of electric current of described load of an expression.
8. AC/DC converter circuit according to claim 2 is characterized in that the signal of the voltage that described feedback signal is an expression in the described load.
9. AC/DC converter circuit according to claim 1 is characterized in that when described feedback signal is represented open-circuit condition, described drive circuit control switch conducting state, thus reduce power to the first level of described load.
10. AC/DC converter circuit according to claim 9 is characterized in that described first level is zero.
11. AC/DC converter circuit according to claim 9, it is characterized in that described first level be one greater than zero electricity value.
12. AC/DC converter circuit according to claim 1, the resistance that it is characterized in that representing load when described feedback signal is during greater than a particular value, described drive circuit control switch conducting state, thus power to the first level of described load reduced.
13. AC/DC converter circuit according to claim 12 is characterized in that described first level is zero.
14. AC/DC converter circuit according to claim 12, it is characterized in that described first level be one greater than zero value.
15. AC/DC converter circuit according to claim 12, it is characterized in that described particular value be one greater than 130 kilohms resistance.
16. AC/DC converter circuit according to claim 1 is characterized in that when described feedback signal is represented short-circuit condition, described drive circuit control switch conducting state, thus reduce power to the first level of described load.
17. AC/DC converter circuit according to claim 1 is characterized in that this circuit also comprises a cold-cathode fluorescence lamp (CCFL) load that links to each other with described secondary coil.
18. AC/DC converter circuit according to claim 1 is characterized in that this circuit also comprises an input voltage source that described voltage is provided.
19. AC/DC converter circuit according to claim 18 is characterized in that this circuit also comprises a cold-cathode fluorescence lamp (CCFL) control board load that links to each other with described secondary coil.
20. AC/DC converter circuit according to claim 19 is characterized in that this circuit also comprises a motherboard that links to each other with the load of described cold-cathode fluorescence lamp (CCFL) control board.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200420001507 CN2710247Y (en) | 2004-01-02 | 2004-01-02 | High-efficient switch circuit for non-linear load |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200420001507 CN2710247Y (en) | 2004-01-02 | 2004-01-02 | High-efficient switch circuit for non-linear load |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2710247Y true CN2710247Y (en) | 2005-07-13 |
Family
ID=34848270
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200420001507 Ceased CN2710247Y (en) | 2004-01-02 | 2004-01-02 | High-efficient switch circuit for non-linear load |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2710247Y (en) |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102468772A (en) * | 2010-11-08 | 2012-05-23 | 通用汽车环球科技运作有限责任公司 | Compensation for electrical converter nonlinearities |
| CN101336508B (en) * | 2006-02-01 | 2012-05-30 | Abb研究有限公司 | Switchgear cell and converter circuit for switching a large number of voltage levels |
| CN101605422B (en) * | 2008-06-13 | 2012-11-07 | 尼克森微电子股份有限公司 | Fluorescent lighting tube driving circuit |
| CN102810891A (en) * | 2011-05-31 | 2012-12-05 | 通用汽车环球科技运作有限责任公司 | Systems and methods for initializing a charging system |
| CN103235629A (en) * | 2012-03-30 | 2013-08-07 | 上海拜安实业有限公司 | Circuit structure capable of realizing automatic regulation and control of output power and corresponding method |
| CN103477550A (en) * | 2012-02-23 | 2013-12-25 | 株式会社京三制作所 | Current source inverter device, and method for controlling current source inverter device |
| US8860379B2 (en) | 2011-04-20 | 2014-10-14 | GM Global Technology Operations LLC | Discharging a DC bus capacitor of an electrical converter system |
| US8878495B2 (en) | 2011-08-31 | 2014-11-04 | GM Global Technology Operations LLC | Systems and methods for providing power to a load based upon a control strategy |
| US9729004B2 (en) | 2014-11-13 | 2017-08-08 | Inventec (Pudong) Technology Corporation | Power source protection device and method |
| US9770991B2 (en) | 2013-05-31 | 2017-09-26 | GM Global Technology Operations LLC | Systems and methods for initializing a charging system |
| CN107677467A (en) * | 2017-09-25 | 2018-02-09 | 哈尔滨工业大学 | A kind of Novel bunk temperature nonlinearizer Real time Efficiency is test bed and its test method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101336508B (en) * | 2006-02-01 | 2012-05-30 | Abb研究有限公司 | Switchgear cell and converter circuit for switching a large number of voltage levels |
| CN101605422B (en) * | 2008-06-13 | 2012-11-07 | 尼克森微电子股份有限公司 | Fluorescent lighting tube driving circuit |
| CN102468772A (en) * | 2010-11-08 | 2012-05-23 | 通用汽车环球科技运作有限责任公司 | Compensation for electrical converter nonlinearities |
| CN102468772B (en) * | 2010-11-08 | 2014-11-26 | 通用汽车环球科技运作有限责任公司 | Compensation for electrical converter nonlinearities |
| US8860379B2 (en) | 2011-04-20 | 2014-10-14 | GM Global Technology Operations LLC | Discharging a DC bus capacitor of an electrical converter system |
| CN102810891A (en) * | 2011-05-31 | 2012-12-05 | 通用汽车环球科技运作有限责任公司 | Systems and methods for initializing a charging system |
| CN102810891B (en) * | 2011-05-31 | 2015-11-04 | 通用汽车环球科技运作有限责任公司 | For the system and method for initialization charging system |
| US8829858B2 (en) | 2011-05-31 | 2014-09-09 | GM Global Technology Operations LLC | Systems and methods for initializing a charging system |
| US8878495B2 (en) | 2011-08-31 | 2014-11-04 | GM Global Technology Operations LLC | Systems and methods for providing power to a load based upon a control strategy |
| CN103477550A (en) * | 2012-02-23 | 2013-12-25 | 株式会社京三制作所 | Current source inverter device, and method for controlling current source inverter device |
| CN103477550B (en) * | 2012-02-23 | 2015-06-17 | 株式会社京三制作所 | Current source inverter device, and method for controlling current source inverter device |
| CN103235629B (en) * | 2012-03-30 | 2014-12-17 | 上海拜安实业有限公司 | Circuit structure capable of realizing automatic regulation and control of output power and corresponding method |
| CN103235629A (en) * | 2012-03-30 | 2013-08-07 | 上海拜安实业有限公司 | Circuit structure capable of realizing automatic regulation and control of output power and corresponding method |
| US9770991B2 (en) | 2013-05-31 | 2017-09-26 | GM Global Technology Operations LLC | Systems and methods for initializing a charging system |
| US9729004B2 (en) | 2014-11-13 | 2017-08-08 | Inventec (Pudong) Technology Corporation | Power source protection device and method |
| CN107677467A (en) * | 2017-09-25 | 2018-02-09 | 哈尔滨工业大学 | A kind of Novel bunk temperature nonlinearizer Real time Efficiency is test bed and its test method |
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