CN101630914B - Stabilized voltage supply convertor with long service life and low electromagnetic interference - Google Patents
Stabilized voltage supply convertor with long service life and low electromagnetic interference Download PDFInfo
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- CN101630914B CN101630914B CN 200910042128 CN200910042128A CN101630914B CN 101630914 B CN101630914 B CN 101630914B CN 200910042128 CN200910042128 CN 200910042128 CN 200910042128 A CN200910042128 A CN 200910042128A CN 101630914 B CN101630914 B CN 101630914B
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Abstract
The invention discloses a stabilized voltage supply convertor with long service life and low electromagnetic interference, comprising a resonance half-bridge circuit, a piezoelectric ceramics transformer, a rectification output circuit, a degenerative circuit and an isolation drive circuit. The invention is characterized in that the stabilized voltage supply converter also comprises a drive circuit with a fixed frequency and a PWM control circuit, wherein, the drive circuit with a fixed frequency is connected between the resonance half-bridge circuit and the isolation drive circuit, and the PWM control circuit is connected between the degenerative circuit and the isolation drive circuit; the output of the resonance half-bridge circuit is connected with the input end of the piezoelectric ceramics transformer which is output by the rectification circuit; the output feedback sampling voltage of the supply convertor is connected with the PWM control circuit via the degenerative circuit; the PWM output of the PWM control circuit controls the driving duty ratio of the isolation drive circuit which drives the on-off or cut-off of the drive circuit with a fixed frequency; thus, the resonance half-bridge circuit controlled by the drive circuit with a fixed frequency is in the mode of intermittent working, and the time ratio of the intermittent working is determined by the driving duty ratio of the isolation drive circuit.
Description
Technical field
The present invention relates to a kind of supply convertor, particularly relate to a kind of stabilized voltage supply convertor with long service life and low electromagnetic interference.
Background technology
Piezoelectric ceramic transformer has begun to be applied in more and more field of switch power with its outstanding performance advantage, and comparatively common a kind of mode is that resonance half-bridge circuit is applied in the piezoelectric ceramic transformer supply convertor at present, its circuit structure as shown in Figure 1, comprise: 1) resonance half-bridge circuit, form by two serial connection switching tube Q1, Q2; 2) piezoelectric ceramic transformer: form by piezoelectric ceramic transformer; 3) rectification circuit part: mainly by rectification circuit, capacitor C 1, load resistance R
LoadAnd sampling resistor R
Sense1, R
Sense2Form; 4) negative-feedback circuit part: mainly partly form by a reference voltage source and compensating circuit; 5) PFM (frequency modulation mode) control circuit part; 6) isolated drive circuit part: comprise driving transformer or drive optocoupler.Thereby the operation principle of this circuit mainly is to utilize transformer to have different output gains to reach constant voltage output with resonant inductance for different frequencies.The difference of output voltage and setting voltage influences PFM by feedback loop, thereby changes the operating frequency of circuit, reaches the difference of progressively dwindling output voltage and setting voltage, finally realizes the purpose of constant voltage output.
Though this circuit can be realized soft switch, efficient is higher, control is also uncomplicated, but also there are some shortcomings in it: thus must be that the control of frequency conversion rate could realize that the stable output of voltage causes a lot of problems relevant with frequency change such as test and the rectification of EMI, and need be at resonant inductance of the former limit series connection of piezoelectric ceramic transformer in order to realize soft switch than wider frequency.And the existence of resonant inductance will increase undoubtedly converter volume, raise the cost, increase loss, can guarantee that it will be very significant that circuit can also have identical functions if can remove resonant inductance.
Summary of the invention
Purpose of the present invention provides under a kind of situation that can remove resonant inductance, realizes the stabilized voltage supply convertor of low electromagnetic interference of long-life.
The present invention realizes by following technical scheme: a kind of stabilized voltage supply convertor with long service life and low electromagnetic interference, comprise resonance half-bridge circuit, piezoelectric ceramic transformer, rectifying output circuit, negative-feedback circuit, isolated drive circuit, it is characterized in that also comprising and decide frequency drives circuit, pwm control circuit; Deciding the frequency drives circuit is connected between resonance half-bridge circuit and the isolated drive circuit; Pwm control circuit is connected between negative-feedback circuit and the isolated drive circuit; The output of above-mentioned resonance half-bridge circuit is connected to the input of above-mentioned piezoelectric ceramic transformer, and above-mentioned piezoelectric ceramic transformer is exported through rectification circuit; The output feedback sample voltage of above-mentioned supply convertor connects described pwm control circuit through described negative-feedback circuit; The driving duty ratio of the described isolated drive circuit of PWM output control of described pwm control circuit, described isolated drive circuit drives to be located at describedly to be decided the conducting of frequency drives circuit or ends, thereby allow described resonance half-bridge circuit of deciding the control of frequency drives circuit be in the intermittently used pattern, intermittently used time ratio depends on the driving duty ratio of described isolated drive circuit.
Of the present inventionly decide the frequency drives circuit and comprise that deciding frequency decides the pulsewidth chip for driving, the 3rd switching tube; The grid of described the 3rd switching tube is connected in the output of described isolated drive circuit; The drain electrode of described the 3rd switching tube and source electrode are serially connected with in the power supply major loop of resonance half-bridge circuit, the source electrode of described the 3rd switching tube and the described negative pole of deciding the working power of frequency drives chip with reference to the power supply major loop of termination resonance half-bridge circuit; Decide corresponding two inputs that connect resonance half-bridge circuit of two outputs of frequency drives chip.
The drain electrode of above-mentioned in addition the 3rd switching tube is serially connected with the described working power reference edge of deciding the frequency drives chip, and the Enable Pin of perhaps deciding the frequency drives chip is perhaps decided the synchronous end of frequency drives chip, also can implement technical solution of the present invention.
Compared with prior art, the present invention has following characteristics:
1, removed the resonant inductance in the traditional circuit, reduced the volume of converter, and still can realize soft switching function.Iron loss on traditional resonant inductance and copper loss all are very important, therefore by removing the efficient that resonant inductance also can improve converter;
2, realize the burning voltage output soft switching power converter of high and low frequency superposing control, it is more mature and stable than the PFM controlling schemes to use the PWM controlling schemes, and circuit reliability is higher;
3, the frequency of circuit is constant, contrasts traditional scheme of adjusting frequency and will make things convenient in the debugging of EMI a lot, because only need adjust the situation of respective frequencies point, and does not need whole frequency band is assessed.
Description of drawings
Fig. 1 is the schematic diagram of prior art;
Fig. 2 is a principle of the invention block diagram;
Fig. 3 is the schematic diagram of embodiment of the present invention one;
Fig. 4 is the schematic diagram of embodiment of the present invention two;
Fig. 5 is the schematic diagram of embodiment of the present invention three;
Fig. 6 is the schematic diagram of embodiment of the present invention four;
Embodiment
As shown in Figure 2, mainly comprise following part: 1) decide the frequency drives circuit part: mainly form by the square-wave generator of deciding frequency drives chip or fixed frequency and duty ratio, switching tube Q3; 2) resonance half-bridge circuit is made up of two switching tube Q1, Q2; 3) piezoelectric ceramic transformer: form by piezoelectric ceramic transformer; 4) rectification circuit part: mainly form by rectification circuit, capacitor C 1, load resistance Rload and sampling resistor Rsense1, Rsense2; 4) negative-feedback circuit part: mainly partly form by a reference voltage source and compensating circuit; 5) pwm control circuit part (general PWM chip such as UC3843 etc.); 6) isolated drive circuit part: adopt driving transformer or drive optocoupler.Deciding the frequency drives circuit is connected between resonance half-bridge circuit and the isolated drive circuit; Pwm control circuit is connected between negative-feedback circuit and the isolated drive circuit; The output of above-mentioned resonance half-bridge circuit is connected to the input of above-mentioned piezoelectric ceramic transformer, and above-mentioned piezoelectric ceramic transformer is exported through rectification circuit; The output feedback sample voltage of above-mentioned supply convertor connects described pwm control circuit through described negative-feedback circuit.
The pwm control circuit controlling and driving is decided the frequency drives circuit and is sent two square wave driving signals, and signal frequency and pulsewidth are all fixed, and its frequency is higher than several times of the frequencies of pwm control circuit to more than tens times.The supply convertor output voltage is through sampling resistor R
Sense1, R
Sense2Enter negative-feedback circuit, thereby influence pwm control circuit, its signal dutyfactor to PWM output is modulated, and go to drive by driving transformer or the isolated drive circuit that drives optocoupler, drive duty ratio big or small final decision the height of output voltage, therefore can be by control duty regulated output voltage recently.And itself natural resonance frequency of the fixed frequency drive circuit of higher frequency and piezoelectric ceramic transformer is complementary (being the natural frequency of operating frequency) a little more than piezoelectric transformer.Simultaneously, because the inside equivalent parameters of piezoelectric transformer can be controlled on material and sintering process as required, and the circuit fixed frequency that matches also can artificially be set by revising circuit parameter, therefore thisly can in circuit, save extra resonant inductance by the matching relationship of artificial setting, as long as utilize in the inner equivalent electric circuit of piezoelectric ceramic transformer stray inductance L (as shown in Figure 3), can realize soft switching function.
The specific embodiment of the present invention one circuit theory diagrams as shown in Figure 3, two switching tube Q1, Q2 in the resonance half-bridge circuit connect mutually, the source electrode of switching tube Q1 connects the drain electrode of switching tube Q2, the drain electrode of switching tube Q1 connects positive source, the source electrode of switching tube Q2 connects power cathode, decides the frequency drives circuit and comprises that deciding frequency decides pulsewidth chip for driving and the 3rd switching tube Q3; The grid of the 3rd switching tube Q3 is connected in the output of isolated drive circuit; The drain electrode of the 3rd switching tube Q3 and source electrode are serially connected with in the power supply major loop of resonance half-bridge circuit, the source electrode of the 3rd switching tube Q3 and decide the negative pole of the working power of frequency drives chip with reference to the power supply major loop of termination resonance half-bridge circuit; Two outputs deciding the frequency drives chip are corresponding to connect two switching tube Q1, Q2 grid among two of resonance half-bridge circuit.
Output voltage is through sampling resistor R
Sense1, R
Sense2Obtain being adapted to the voltage signal of pwm chip after the dividing potential drop, pwm chip adopts the existing integrated chip of negative feedback control commonly used, utilizes the sampled voltage signal to control the pulsewidth of PWM; Pulse width signal removes driving switch pipe Q3 through the isolation drive transformer, when switching tube Q3 conducting, decide frequency decide the resonance half-bridge circuit of pulsewidth chip for driving IC control can operate as normal, energy grade is provided after giving; When switching tube Q3 ended, resonance half-bridge circuit quit work, and level is transmitted energy backward.Therefore can be by the pulsewidth of control PWM, promptly control the purpose that resonance half-bridge circuit work and the time scale that stops to reach control output voltage.
The specific embodiment of the present invention two circuit theory diagrams as shown in Figure 4, its groundwork principle is consistent with Fig. 3, it is not to cut off major loop by switching tube Q3 that difference is to control resonance half-bridge circuit intermittently used method, but cuts off the current supply circuit of deciding frequency drives circuit control chip by switching tube Q3.The grid of above-mentioned the 3rd switching tube Q3 is connected in the output of described isolated drive circuit; The drain electrode of the 3rd switching tube Q3 is serially connected with the working power reference edge of deciding the frequency drives chip, and the source electrode of the 3rd switching tube Q3 connects the negative pole of the power supply major loop of resonance half-bridge circuit; When the 3rd switching tube Q3 conducting, deciding the frequency drives circuit can operate as normal, and level provides energy backward; When the 3rd switching tube Q3 ends, then decide frequency drives circuit level transmission energy backward.Therefore pulsewidth that can be by control PWM, and the driving duty of the 3rd switching tube Q3 recently reach the purpose of control and regulated output voltage.This kind execution mode is compared with execution mode one, can end to reach making the intermittently used purpose equally by the conducting of the 3rd switching tube Q3, and in this embodiment, because the 3rd switching tube Q3 is not connected in the main loop of power circuit, so power-efficient can be higher.
In addition, the 3rd switching tube Q3 can also be placed on the anode of input, as the top of Vcc.If but the soft start function of deciding the frequency drives chip in this scheme moves, will have influence on the output ripple size of circuit when operate as normal.Therefore the parameter that needs the appropriate design soft-start circuit, making that soft-start circuit can not reset under the corresponding time constant grade of secondary frequency restarts.That is to say that under this application scenario soft-start circuit only works under circuit restarts situation, and when operate as normal and be failure to actuate.
The specific embodiment of the present invention three-circuit schematic diagram as shown in Figure 5, its groundwork principle is consistent with Fig. 3, this kind circuit is the very strong embodiment of a kind of practicality, but this scheme needs the frequency drives chip of deciding on former limit that an Enable Pin is arranged, the 3rd switching tube Q3 can be connect the Enable Pin of chip for driving, thereby the conducting of passing through the 3rd switching tube Q3 is exported with the frequency drives chip drives signal of deciding by effect control; The grid of above-mentioned the 3rd switching tube Q3 is connected in the output of described isolated drive circuit; The 3rd switching tube Q3 source electrode and the described negative pole of deciding the working power of frequency drives chip with reference to the power supply major loop of termination resonance half-bridge circuit, the drain electrode of the 3rd switching tube Q3 connects the Enable Pin of chip for driving.Particularly, when the 3rd switching tube Q3 ends, make that should decide frequency drives chip enable end unsettled, then decide the normal output drive signal of frequency drives chip and arrive first and second switching tube Q1 and Q2; And when the 3rd switching tube Q3 conducting, make and decide the frequency drives chip and can hold ground connection, then do not export drive signal to first and second switching tube Q1 and Q2.
Because the 3rd switching tube Q3 is not connected in the main loop of power circuit yet in this scheme, so circuit efficiency is compared to execution mode one and Yan Genggao; And the soft start function of deciding the frequency drives chip can operate as normal, and does not influence output voltage ripple.Therefore this kind embodiment relatively is better than preceding two kinds of execution modes, has under the situation of Enable Pin decide the frequency drives chip, recommends this kind of use scheme.
The specific embodiment of the present invention four circuit theory diagrams as shown in Figure 6, circuit basically identical in itself and the execution mode three (Fig. 5), the Enable Pin that the different just drain electrodes of the 3rd switching tube Q3 connects chip for driving becomes synchronous end, thereby the mode of operation of entire circuit all changes.Above several embodiment are based upon on two bases, and at first, the operating frequency of deciding the frequency drives circuit on former limit is greater than the frequency of pwm control circuit, and half is selected greater than more than 10 times; Secondly, the pulsewidth of deciding the frequency drives circuit could be removed the afterflow inductance at output like this near 50%.And the circuit working principle is among Fig. 6: when deciding the frequency drives circuit and do not have synchronizing signal, drive signal is fixed on some duty ratios, in case and pwm chip is started working, behind the driving switch pipe Q3, decide the frequency drives chip and will follow the pulsewidth of synchronous end, thereby make circuit working under the pattern of modulation pulsewidth.
Embodiments of the present invention are not limited thereto, according to foregoing of the present invention, ordinary skill knowledge and customary means according to this area, do not breaking away under the above-mentioned basic fundamental thought of the present invention prerequisite, the present invention can also make equivalent modifications, replacement or the change of other various ways, all can realize the object of the invention.
Claims (4)
1. one kind low electromagnetic interference stabilized voltage supply convertor comprises resonance half-bridge circuit, piezoelectric ceramic transformer, rectifying output circuit, negative-feedback circuit, isolated drive circuit, decides frequency drives circuit, pwm control circuit; Deciding the frequency drives circuit is connected between resonance half-bridge circuit and the isolated drive circuit; Pwm control circuit is connected between negative-feedback circuit and the isolated drive circuit; The output of above-mentioned resonance half-bridge circuit is connected to the input of above-mentioned piezoelectric ceramic transformer, and above-mentioned piezoelectric ceramic transformer is exported through rectification circuit; The output feedback sample voltage of above-mentioned supply convertor connects described pwm control circuit through described negative-feedback circuit; The driving duty ratio of the described isolated drive circuit of PWM output control of described pwm control circuit, described isolated drive circuit drives to be located at describedly to be decided the conducting of frequency drives circuit or ends, thereby allow described resonance half-bridge circuit of deciding the control of frequency drives circuit be in the intermittently used pattern, intermittently used time ratio depends on the driving duty ratio of described isolated drive circuit;
It is characterized in that: describedly decide the frequency drives circuit and comprise that deciding frequency decides the pulsewidth chip for driving, the 3rd switching tube; The grid of described the 3rd switching tube is connected in the output of described isolated drive circuit; The drain electrode of described the 3rd switching tube and source electrode are serially connected with in the power supply major loop of resonance half-bridge circuit, the source electrode of described the 3rd switching tube and describedly decide frequency and decide the negative pole of the working power of pulsewidth chip for driving with reference to the power supply major loop of termination resonance half-bridge circuit; Decide corresponding two inputs that connect resonance half-bridge circuit of two outputs that frequency is decided the pulsewidth chip for driving.
2. one kind low electromagnetic interference stabilized voltage supply convertor comprises resonance half-bridge circuit, piezoelectric ceramic transformer, rectifying output circuit, negative-feedback circuit, isolated drive circuit, decides frequency drives circuit, pwm control circuit; Deciding the frequency drives circuit is connected between resonance half-bridge circuit and the isolated drive circuit; Pwm control circuit is connected between negative-feedback circuit and the isolated drive circuit; The output of above-mentioned resonance half-bridge circuit is connected to the input of above-mentioned piezoelectric ceramic transformer, and above-mentioned piezoelectric ceramic transformer is exported through rectification circuit; The output feedback sample voltage of above-mentioned supply convertor connects described pwm control circuit through described negative-feedback circuit; The driving duty ratio of the described isolated drive circuit of PWM output control of described pwm control circuit, described isolated drive circuit drives to be located at describedly to be decided the conducting of frequency drives circuit or ends, thereby allow described resonance half-bridge circuit of deciding the control of frequency drives circuit be in the intermittently used pattern, intermittently used time ratio depends on the driving duty ratio of described isolated drive circuit;
It is characterized in that: describedly decide the frequency drives circuit and comprise that deciding frequency decides the pulsewidth chip for driving, the 3rd switching tube; The grid of described the 3rd switching tube is connected in the output of described isolated drive circuit; The drain electrode of described the 3rd switching tube is serially connected with the described working power reference edge that frequency is decided the pulsewidth chip for driving of deciding, and the source electrode of described the 3rd switching tube connects the negative pole of the power supply major loop of resonance half-bridge circuit; Decide corresponding two inputs that connect resonance half-bridge circuit of two outputs that frequency is decided the pulsewidth chip for driving.
3. one kind low electromagnetic interference stabilized voltage supply convertor comprises resonance half-bridge circuit, piezoelectric ceramic transformer, rectifying output circuit, negative-feedback circuit, isolated drive circuit, decides frequency drives circuit, pwm control circuit; Deciding the frequency drives circuit is connected between resonance half-bridge circuit and the isolated drive circuit; Pwm control circuit is connected between negative-feedback circuit and the isolated drive circuit; The output of above-mentioned resonance half-bridge circuit is connected to the input of above-mentioned piezoelectric ceramic transformer, and above-mentioned piezoelectric ceramic transformer is exported through rectification circuit; The output feedback sample voltage of above-mentioned supply convertor connects described pwm control circuit through described negative-feedback circuit; The driving duty ratio of the described isolated drive circuit of PWM output control of described pwm control circuit, described isolated drive circuit drives to be located at describedly to be decided the conducting of frequency drives circuit or ends, thereby allow described resonance half-bridge circuit of deciding the control of frequency drives circuit be in the intermittently used pattern, intermittently used time ratio depends on the driving duty ratio of described isolated drive circuit;
It is characterized in that: describedly decide the frequency drives circuit and comprise that deciding frequency decides the pulsewidth chip for driving, the 3rd switching tube; The grid of described the 3rd switching tube is connected in the output of described isolated drive circuit; The drain electrode of described the 3rd switching tube is connected in the described Enable Pin that frequency is decided the pulsewidth chip for driving of deciding, the source electrode of described the 3rd switching tube and describedly decide frequency and decide the negative pole of the working power of pulsewidth chip for driving with reference to the power supply major loop of termination resonance half-bridge circuit; Decide corresponding two inputs that connect resonance half-bridge circuit of two outputs of frequency drives circuit.
4. one kind low electromagnetic interference stabilized voltage supply convertor comprises resonance half-bridge circuit, piezoelectric ceramic transformer, rectifying output circuit, negative-feedback circuit, isolated drive circuit, decides frequency drives circuit, pwm control circuit; Deciding the frequency drives circuit is connected between resonance half-bridge circuit and the isolated drive circuit; Pwm control circuit is connected between negative-feedback circuit and the isolated drive circuit; The output of above-mentioned resonance half-bridge circuit is connected to the input of above-mentioned piezoelectric ceramic transformer, and above-mentioned piezoelectric ceramic transformer is exported through rectification circuit; The output feedback sample voltage of above-mentioned supply convertor connects described pwm control circuit through described negative-feedback circuit; The driving duty ratio of the described isolated drive circuit of PWM output control of described pwm control circuit, described isolated drive circuit drives to be located at describedly to be decided the conducting of frequency drives circuit or ends, thereby allow described resonance half-bridge circuit of deciding the control of frequency drives circuit be in the intermittently used pattern, intermittently used time ratio depends on the driving duty ratio of described isolated drive circuit;
It is characterized in that: describedly decide the frequency drives circuit and comprise that deciding frequency decides the pulsewidth chip for driving, the 3rd switching tube; The grid of described the 3rd switching tube is connected in the output of described isolated drive circuit; The drain electrode of described the 3rd switching tube is connected in the described synchronous end that frequency is decided the pulsewidth chip for driving of deciding, the source electrode of described the 3rd switching tube and describedly decide frequency and decide the negative pole of the working power of pulsewidth chip for driving with reference to the power supply major loop of termination resonance half-bridge circuit; Decide corresponding two inputs that connect resonance half-bridge circuit of two outputs of frequency drives circuit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200910042128 CN101630914B (en) | 2009-08-26 | 2009-08-26 | Stabilized voltage supply convertor with long service life and low electromagnetic interference |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200910042128 CN101630914B (en) | 2009-08-26 | 2009-08-26 | Stabilized voltage supply convertor with long service life and low electromagnetic interference |
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| Publication Number | Publication Date |
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| CN101630914A CN101630914A (en) | 2010-01-20 |
| CN101630914B true CN101630914B (en) | 2011-08-17 |
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| CN 200910042128 Expired - Fee Related CN101630914B (en) | 2009-08-26 | 2009-08-26 | Stabilized voltage supply convertor with long service life and low electromagnetic interference |
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Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105322797A (en) * | 2014-07-22 | 2016-02-10 | 北京嘉昌机电设备制造有限公司 | Improved half-bridge topology circuit |
| CN109617421B (en) * | 2019-01-22 | 2023-12-26 | 富满微电子集团股份有限公司 | Switch power supply control chip and self-adaptive line network voltage compensation circuit thereof |
| CN116418238B (en) * | 2023-06-08 | 2023-08-15 | 西南交通大学 | Three-switch half-bridge wide-range LLC resonant converter and use method thereof |
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