CN201846243U - Zero-crossing detection circuit of switching power supply - Google Patents
Zero-crossing detection circuit of switching power supply Download PDFInfo
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- CN201846243U CN201846243U CN2010206294985U CN201020629498U CN201846243U CN 201846243 U CN201846243 U CN 201846243U CN 2010206294985 U CN2010206294985 U CN 2010206294985U CN 201020629498 U CN201020629498 U CN 201020629498U CN 201846243 U CN201846243 U CN 201846243U
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Abstract
The utility model discloses a zero-crossing detection circuit of a switching power supply, which is applied to a switching power supply circuit system, and comprises a reference voltage generation module, a zero-crossing comparator and a pulse width detection module, the pulse width output by the zero-crossing comparator is filtered by the pulse width detection module, so the error judgment of the zero-crossing comparator is effectively eliminated, therefore, the reliability of the zero-crossing detection is improved.
Description
Technical field
The utility model relates to the switch power technology field, particularly relates to a kind of zero cross detection circuit of Switching Power Supply.
Background technology
Switching Power Supply more and more is applied in the various kinds of equipment because volume is little and the high advantage of efficient, is used to the energy output that provides stable.
Adopt traditional non-control rectifier switch power supply,, have big phase difference between net side input voltage and input current because input impedance is capacitive, add the serious non-sine of input current, and be pulse type, so power factor is extremely low, harmonic component is very high, has brought serious harmonic pollution to electric power system.For this reason, International Electrotechnical Commission has early just formulated the IEC1000-3-2 standard in the early 1990s, and the power factor of strict qualification equipment must approach 1, and the power factor that improves Switching Power Supply has become the task of top priority of domestic power supply manufacturer.
Because input has rectifier cell and filter capacitor, single-phase AC/DC Switching Power Supply and most of rectifier power source electronic equipment powered, its grid side power factor only are about 0.65.Can bring up to 0.95～0.99 after adopting the active power alignment technique, both administer the harmonic pollution of electrical network, improve the whole efficiency of Switching Power Supply again.
The active PFC technology that is widely adopted at present is a two-step scheme, that is: (active) power factor correction (PFC) booster converter and DC-DC converter.The two-stage pfc converter uses two switches (being generally MOSFET) and two controllers, i.e. a power factor controller and a PWM controller.Only when adopting PFC/PWM combined controller IC, could use a controller, but still need with two switches.Two-stage PFC is very ripe technically, obtains extensive use already, but there is the complicated and more high shortcoming of cost of circuit topology in this scheme.
The shared switching tube of PFC level in the single-stage PFC AC-DC converter and DC-DC level and adopt a cover control circuit of PWM mode is realized power factor correction simultaneously and to the adjusting of output voltage, can be overcome the shortcoming of above-mentioned two-stage form.
As be applied in the single-stage PFC AC-DC converter of LED lighting field, as shown in Figure 1.Because the drive part of LED needs constant current output, therefore, the controller of secondary has constant voltage (CV) and the control of constant current (CC) two-way usually.Drive in the application in the LED illumination, when the output voltage short circuit, from the output characteristic curve Fig. 2 of system, can see that system should be operated under the CC pattern.Because system's output short-circuit, the voltage of Vout is near 0v, and former limit pfc controller 12 is still in running order.And work principle is consistent with normal operating conditions.That is, after each power MOS pipe 10 conductings, inductive current increases, and the voltage on current sampling resistor reaches the reference voltage of current sample comparator.Under the situation of PFC operate as normal, the reference voltage of current sample comparator is a sinusoidal signal.Each power MOS pipe closes has no progeny, and the PFC control chip detects inductive current and is decreased to zero, then once more power MOS pipe is placed conducting state.The rate of change of secondary inductance electric current, relevant with the size of output voltage, its concrete formula is as follows:
Wherein, Ipk is the current peak of former limit inductance, and N1/N2 is the source secondary turn ratio, and Vout is an output voltage, and Vs is a secondary Schottky diode forward conduction voltage drop.By top formula as can be seen, be in system under the situation of output short circuit, the secondary inductance current changing rate diminishes, and the secondary Schottky diode forward conduction time is elongated.Therefore, the switching frequency of the PFC control chip 12 on former limit diminishes, and makes the power output of whole system reduce.
But in the Circuits System of reality, the voltage waveform on the auxiliary winding is because can there be certain concussion voltage waveform in the influence of parasitic capacitance and transformer leakage inductance.This concussion voltage waveform is superimposed upon on the direct voltage Vout+Vs (diode 13 forward conduction voltages).When output voltage is high,, dc offset voltage can the work of former limit pfc controller not exerted an influence because, shaking voltage than higher.But when system's output voltage is lower, particularly the output voltage short circuit time, this DC component only equals the forward conduction voltage drop of Schottky diode 13.Shake voltage and can the work of former limit pfc controller be exerted an influence this moment.After former limit PFC control signal detects wrong inductive current zero cross signal, can open/switch-off power MOS device with very high frequency.Like this, inductive current enters continuous conduction mode not being reduced under 0 the situation, and its electric current can constantly increase along with the increase of switch number of times, saturated or trigger certain error condition of former limit PFC control chip up to inductance, for example: the overvoltage condition of CS and power MOS pipe drain break down.
Therefore, be necessary the current over-zero detection module is improved, the system that makes is unlikely under low output voltage situation very and enters very high switching frequency, causes system to be in dangerous work.
With reference to figure 3 and Fig. 4, Fig. 3 is the circuit theory diagrams of existing inductive current zero cross detection circuit, and there is a current over-zero detection line inside of former limit FPC.Its operation principle is as follows:
When ZCD (zero current cross detection) voltage surpasses the first thresholding Vth1 of current over-zero comparator, the output voltage of comparator is high, as shown in the figure, this voltage is that the forward conduction voltage drop 3*Vdiode. of 3 diodes is when the output voltage of comparator when being high, the gate voltage of switching tube 105 also is a high level, and switching tube 105 is placed in conducting state.Diode 104 is by short circuit, so the reference voltage of current over-zero comparator is switched to the forward conduction voltage drop 2*Vdiode of 2 diodes (102 and 103).This voltage is the second reference voltage V th2.When the ZCD signal was dropped to voltage less than Vth2 by the voltage greater than Vth1, the current over-zero comparator was output as low level.
With reference to figure 4, be that Fig. 1 assists the waveform schematic diagram on the winding and judges the rub-out signal that current over-zero detects and wish detected correct signal comparison diagram that as shown in the figure, the operation principle of current over-zero detection line in system is as follows:
When the power MOS pipe conducting, the voltage on the auxiliary winding is negative value.Inductive current rises since 0.During to inductive current arrival cut-off current, power MOS pipe is turned off, and the voltage on the auxiliary winding just becomes, when zero current detection (ZCD) voltage surpasses the first thresholding Vth1, zero-crossing comparator is exported high level signal, and the reference voltage of zero-crossing comparator is switched to the second thresholding Vth2.After the conducting of secondary Schottky diode, the voltage of ZCD remains on (N1/N2) * (Vout+Vs).After the secondary inductance electric current was decreased to zero, because there are resonance in inductance and parasitic capacitance, the voltage on the auxiliary winding began to descend by resonance frequency.When the voltage on the ZCD dropped to Vth2, zero-crossing comparator overturn once more, output low level, and the reference voltage of zero-crossing comparator switched to the first comparative voltage Vth1.Former limit APFC control signal with power MOS pipe conducting once more, begins next switch periods according to the comparative level of ZCD.So because can there be certain concussion voltage waveform in the voltage waveform on the above-mentioned auxiliary winding under the influence of parasitic capacitance and transformer leakage inductance, thereby it is disconnected to make that erroneous judgement appears in general inductive current zero passage detection module easily.
Therefore, how to design a kind of zero cross detection circuit of Switching Power Supply, avoid above-mentioned generation of false action, become one of technical barrier of current urgent need solution.
The utility model content
In view of this, the purpose of this utility model is to provide a kind of zero cross detection circuit of Switching Power Supply, can effectively avoid the misoperation of zero passage, enhances product performance.
The utility model embodiment provides a kind of zero cross detection circuit of Switching Power Supply, have the zero current cross test side in the described Switching Power Supply, it is characterized in that, zero cross detection circuit comprises: the reference voltage generation module, produce first reference voltage and second reference voltage, and select one of them output; Zero-crossing comparator has input, reference voltage input terminal, reaches output, and wherein, described input is connected with described zero current cross test side, and described reference voltage input terminal is connected with the output of reference voltage generation module; The pulse duration detection module, the output and the reference voltage that are connected in zero-crossing comparator are selected between the module, the output of zero-crossing comparator is carried out the detection of pulse duration, to filter out the output of pulse duration, produce the reference voltage selection signal that the supply reference voltage generation module is selected reference voltage simultaneously less than set point.
In specific embodiment, described reference voltage generation module comprise successively first, second, third diode that connects in the same way and with the switch of ground connection after the 3rd diode is in parallel.Described switch is connected with the output of described pulse duration detection module, selects signal to receive reference voltage, and comes the closure and the disconnection of control switch with this.Described first reference voltage is a described switch when disconnecting, the forward conduction voltage sum of described first, second, third diode; When described second reference voltage is described switch closure, the forward conduction voltage sum of described first, second diode.
In addition, in specific embodiment, described pulse duration detection module can also comprise gun stocks, electric capacity and Schmidt trigger, and wherein, described gun stocks is connected with the output of described zero-crossing comparator; Described electric capacity is connected between described gun stocks and the ground; Described Schmidt trigger is connected in described gun stocks and reference voltage is selected between the module.Described set point is by the triggering level of Schmidt trigger, and the output current of gun stocks and electric capacity determine.
Described Switching Power Supply is the Active Power Factor Correction Switching Power Supply.
Circuit described in the utility model comprises: reference voltage generation module, zero-crossing comparator and pulse duration detection module, by the pulse duration detection module pulse duration of zero-crossing comparator output is filtered, remove to select reference voltage with the output after filtering, making that the erroneous judgement of zero cross detection circuit is disconnected is effectively got rid of, thereby improves the reliability of zero passage detection.
Description of drawings
Fig. 1 is the circuit diagram that is applied in the single-stage PFC AC-DC changer system of LED lighting field;
Fig. 2 is the output characteristic curve figure of system shown in Figure 1;
Fig. 3 is the circuit theory diagrams of existing inductive current zero cross detection circuit;
Fig. 4 is the waveform schematic diagram on the auxiliary winding of Fig. 1 and judges the rub-out signal that current over-zero detects and wish detected correct signal comparison diagram;
Fig. 5 is an embodiment circuit diagram of current over-zero testing circuit of the present utility model;
Fig. 6 is an embodiment circuit diagram of minimum pulse width detection module among Fig. 5;
Fig. 7 is an I/O characteristic curve embodiment illustrated in fig. 6;
Fig. 8 is the oscillogram of each signal of the zero passage detection that provides of the utility model.
Embodiment
For above-mentioned purpose of the present utility model, feature and advantage can be become apparent more, the utility model is described in further detail below in conjunction with the drawings and specific embodiments.
In view of this, the purpose of this utility model is to provide a kind of zero cross detection circuit of Switching Power Supply of Switching Power Supply, can effectively avoid the misoperation of zero passage, enhances product performance.
As mentioned above, when the input signal of comparator contains high frequency ripple, and the ripple amplitude is very big the time, can false triggering current over-zero detection module, and cause system works unusual.Generally, the amplitude of high frequency ripple can be within 1uS because damped oscillation former thereby decay to zero.
Starting point so of the present utility model is: the pulse duration of judging the zero-crossing comparator output signal.If the pulse duration of zero-crossing comparator output signal, thinks then that the reason of trigger current zero passage detection module action this time is the higher-order of oscillation less than certain preset value, simultaneously with this high frequency, the short time pulse filters.After pulse duration is greater than this preset value, think that just the output of zero passage detection module has reflected correct signal.
As shown in Figure 5, be an embodiment circuit diagram of current over-zero testing circuit of the present utility model, a kind of current over-zero testing circuit that the utility model provides comprises reference voltage generation module (102 ', 103 ', 104 '), zero-crossing comparator 110 ' and pulse duration detection module 111.
Wherein, described reference voltage generation module can produce first reference voltage and second reference voltage, and select one of them output, as shown in the figure, in the present embodiment, described reference voltage generation module comprises successively the one 102 ' diode, the 2 103 ' diode, the 3 104 that connects in the same way ' diode and with the 3rd diode 104 ' switch 105 ' of ground connection afterwards in parallel.Above-mentioned switch 105 ' is connected with the output of described pulse duration detection module 111, selects signal to receive reference voltage, and comes the closure and the disconnection of control switch 105 ' with this.First reference voltage is a described switch 105 ' when disconnecting, the forward conduction voltage sum of first, second, third diode; Second reference voltage is a described switch 105 ' when closed, the forward conduction voltage sum of first, second diode.
Described zero-crossing comparator has input, reference voltage input terminal, reaches output, and wherein, input is connected with the zero current cross test side, and reference voltage input terminal is connected with the output of reference voltage generation module.
Described pulse duration detection module, the output and the reference voltage that are connected in zero-crossing comparator are selected between the module, the detection of pulse duration is carried out in the output of zero-crossing comparator, to produce the reference voltage selection signal that the supply reference voltage generation module is selected reference voltage.As shown in Figure 6, in the present embodiment, the pulse duration detection module comprises gun stocks 201, electric capacity 203 and Schmidt trigger 202, and wherein, described gun stocks 201 is connected with the output of described zero-crossing comparator; Described electric capacity 203 is connected between described gun stocks 201 and the ground; Described Schmidt trigger 202 is connected in described gun stocks 201 and reference voltage is selected between the module.
In an embodiment of the present utility model, the operation principle of minimum pulse width detection line as shown in Figure 7.In the rising edge moment of input pulse signal, the output signal of gun stocks 201 begins turning, owing to the voltage on the electric capacity can not suddenly change, so the voltage signal Vcap on the electric capacity begins to descend from high level.If the pulse duration of input is very little, Vcap voltage does not drop to before the upset trigger voltage Vth3 of back one-level Schmidt trigger again, and the output signal of Schmidt trigger does not change.Have only the pulse duration of working as input voltage greater than Tmin, the voltage on the electric capacity is lower than the thresholding of Schmidt trigger, and the output signal of trigger just changes.Like this, pulse duration is filtered less than the input signal of Tmin.
In an embodiment of the present utility model, minimum pulse width Tmin is by the triggering level of Schmidt trigger, and the output current of gun stocks and electric capacity determine.
Consulting Fig. 8 at last, is the oscillogram of each signal of the zero passage detection that provides of the utility model, disconnected at the erroneous judgement of zero passage detection among Fig. 4 as shown in the figure, uses circuit of the present utility model, can successfully get rid of.Like this, the zero passage detection of entire circuit just misoperation can not occur, has improved the performance of product.
More than to the zero cross detection circuit of the Switching Power Supply of a kind of Switching Power Supply provided by the utility model, be described in detail, used specific case herein principle of the present utility model and execution mode are set forth, the explanation of above embodiment just is used for helping to understand method of the present utility model and core concept thereof; Simultaneously, for one of ordinary skill in the art, according to thought of the present utility model, part in specific embodiments and applications all can change.In sum, this description should not be construed as restriction of the present utility model.
Claims (7)
1. the zero cross detection circuit of a Switching Power Supply has the zero current cross test side in the described Switching Power Supply, it is characterized in that, comprising:
The reference voltage generation module produces first reference voltage and second reference voltage, and selects one of them output;
Zero-crossing comparator has input, reference voltage input terminal, reaches output, and wherein, described input is connected with described zero current cross test side, and described reference voltage input terminal is connected with the output of reference voltage generation module;
The pulse duration detection module, the output and the reference voltage that are connected in zero-crossing comparator are selected between the module, the output of zero-crossing comparator is carried out the detection of pulse duration, to filter out the output of pulse duration, produce the reference voltage selection signal that the supply reference voltage generation module is selected reference voltage simultaneously less than set point.
2. the zero cross detection circuit of Switching Power Supply according to claim 1 is characterized in that, described reference voltage generation module comprise successively first, second, third diode that connects in the same way and with the switch of ground connection after the 3rd diode is in parallel.
3. the zero cross detection circuit of Switching Power Supply according to claim 1 and 2 is characterized in that, described switch is connected with the output of described pulse duration detection module, selects signal to receive reference voltage, and comes the closure and the disconnection of control switch with this.
4. the zero cross detection circuit of Switching Power Supply according to claim 1 and 2 is characterized in that, described first reference voltage is a described switch when disconnecting, the forward conduction voltage sum of described first, second, third diode; When described second reference voltage is described switch closure, the forward conduction voltage sum of described first, second diode.
5. the zero cross detection circuit of Switching Power Supply according to claim 1 is characterized in that, described pulse duration detection module comprises gun stocks, electric capacity and Schmidt trigger, and wherein, described gun stocks is connected with the output of described zero-crossing comparator; Described electric capacity is connected between described gun stocks and the ground; Described Schmidt trigger is connected in described gun stocks and reference voltage is selected between the module.
6. the zero cross detection circuit of Switching Power Supply according to claim 5 is characterized in that, described set point is by the triggering level of Schmidt trigger, and the output current of gun stocks and electric capacity determine.
7. the zero cross detection circuit of Switching Power Supply according to claim 1 is characterized in that, described Switching Power Supply is the Active Power Factor Correction Switching Power Supply.
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| CN2010206294985U CN201846243U (en) | 2010-11-18 | 2010-11-18 | Zero-crossing detection circuit of switching power supply |
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| CN2010206294985U CN201846243U (en) | 2010-11-18 | 2010-11-18 | Zero-crossing detection circuit of switching power supply |
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102955066A (en) * | 2011-08-25 | 2013-03-06 | 阿斯科动力科技公司 | Power analysis module for monitoring electrical power source |
| CN103207302A (en) * | 2012-01-17 | 2013-07-17 | 珠海格力电器股份有限公司 | Detecting circuit of discharge current of inductor and power factor correction circuit |
| CN103412181A (en) * | 2013-09-02 | 2013-11-27 | 南京埃科孚电子科技有限公司 | Inductance and current zero-cross detection circuit for correcting boost type power factor |
| CN103457538A (en) * | 2013-09-10 | 2013-12-18 | 昆山新金福精密电子有限公司 | Steady signal generation circuit |
| CN104332940A (en) * | 2014-11-19 | 2015-02-04 | 阳光电源股份有限公司 | Erroneous capture judgment restraining method and device and micro-grid system |
| CN105807125A (en) * | 2016-05-20 | 2016-07-27 | 深圳芯智汇科技有限公司 | Zero-crossing detection circuit and switching power supply including same |
| CN108490246A (en) * | 2012-12-21 | 2018-09-04 | 密克罗奇普技术公司 | Supply voltage zero-crossing detector |
| CN111366778A (en) * | 2018-12-25 | 2020-07-03 | 施耐德电气（澳大利亚）有限公司 | Method and device for detecting zero-crossing times of an electrical signal, electronic regulating device |
| CN113890393A (en) * | 2021-09-27 | 2022-01-04 | 成都芯源系统有限公司 | Switching power supply circuit and control circuit and method thereof |
| CN114527316A (en) * | 2022-04-24 | 2022-05-24 | 深圳市高斯宝电气技术有限公司 | Inductive current zero-crossing detection circuit of CRM mode PFC |
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2010
- 2010-11-18 CN CN2010206294985U patent/CN201846243U/en not_active Expired - Lifetime
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102955066A (en) * | 2011-08-25 | 2013-03-06 | 阿斯科动力科技公司 | Power analysis module for monitoring electrical power source |
| CN102955066B (en) * | 2011-08-25 | 2015-07-22 | 阿斯科动力科技公司 | Power analysis module for monitoring electrical power source |
| US9250274B2 (en) | 2011-08-25 | 2016-02-02 | Asco Power Technologies, L.P. | Power analysis module for monitoring an electrical power source |
| CN103207302A (en) * | 2012-01-17 | 2013-07-17 | 珠海格力电器股份有限公司 | Detecting circuit of discharge current of inductor and power factor correction circuit |
| CN108490246A (en) * | 2012-12-21 | 2018-09-04 | 密克罗奇普技术公司 | Supply voltage zero-crossing detector |
| CN108490246B (en) * | 2012-12-21 | 2021-07-30 | 密克罗奇普技术公司 | Power supply voltage zero-crossing detector |
| CN103412181A (en) * | 2013-09-02 | 2013-11-27 | 南京埃科孚电子科技有限公司 | Inductance and current zero-cross detection circuit for correcting boost type power factor |
| CN103412181B (en) * | 2013-09-02 | 2015-09-16 | 南京埃科孚电子科技有限公司 | For the inductive current zero cross detection circuit that boost power factor corrects |
| CN103457538A (en) * | 2013-09-10 | 2013-12-18 | 昆山新金福精密电子有限公司 | Steady signal generation circuit |
| CN103457538B (en) * | 2013-09-10 | 2016-06-08 | 昆山新金福精密电子有限公司 | Stabilization signal circuit for generating |
| CN104332940A (en) * | 2014-11-19 | 2015-02-04 | 阳光电源股份有限公司 | Erroneous capture judgment restraining method and device and micro-grid system |
| CN104332940B (en) * | 2014-11-19 | 2017-10-17 | 阳光电源股份有限公司 | Suppress method, device and the micro-grid system of capture erroneous judgement |
| CN105807125A (en) * | 2016-05-20 | 2016-07-27 | 深圳芯智汇科技有限公司 | Zero-crossing detection circuit and switching power supply including same |
| CN111366778A (en) * | 2018-12-25 | 2020-07-03 | 施耐德电气（澳大利亚）有限公司 | Method and device for detecting zero-crossing times of an electrical signal, electronic regulating device |
| CN111366778B (en) * | 2018-12-25 | 2022-12-27 | 施耐德电气（澳大利亚）有限公司 | Method and device for detecting the zero crossing of an electrical signal, electronic regulating device |
| CN113890393A (en) * | 2021-09-27 | 2022-01-04 | 成都芯源系统有限公司 | Switching power supply circuit and control circuit and method thereof |
| CN114527316A (en) * | 2022-04-24 | 2022-05-24 | 深圳市高斯宝电气技术有限公司 | Inductive current zero-crossing detection circuit of CRM mode PFC |
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Granted publication date: 20110525 |