CN117410934B - Bridgeless PFC input undervoltage protection circuit - Google Patents
Bridgeless PFC input undervoltage protection circuit Download PDFInfo
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- CN117410934B CN117410934B CN202311721924.6A CN202311721924A CN117410934B CN 117410934 B CN117410934 B CN 117410934B CN 202311721924 A CN202311721924 A CN 202311721924A CN 117410934 B CN117410934 B CN 117410934B
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- 239000003990 capacitor Substances 0.000 claims description 16
- 238000005070 sampling Methods 0.000 claims description 9
- 230000000694 effects Effects 0.000 claims description 3
- 238000001914 filtration Methods 0.000 claims 1
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000009191 jumping Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/24—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to undervoltage or no-voltage
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0092—Details of emergency protective circuit arrangements concerning the data processing means, e.g. expert systems, neural networks
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
- H02M1/4208—Arrangements for improving power factor of AC input
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
- H03K17/687—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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- Engineering & Computer Science (AREA)
- Artificial Intelligence (AREA)
- Evolutionary Computation (AREA)
- Power Engineering (AREA)
- Rectifiers (AREA)
Abstract
The bridgeless PFC input undervoltage protection circuit comprises an L-phase signal end and an N-phase signal end; the positive phase end of the differential operational amplifier unit U1B is connected with the L-phase signal end, the negative phase end of the differential operational amplifier unit U1B is connected with the N-phase signal end, and the output end of the differential operational amplifier unit U1B outputs half-wave voltage; the output end of the differential operational amplifier unit U1B is sequentially connected with a diode D1 and a resistor R7, the resistor R7 is connected with the negative phase end of the comparison operational amplifier unit U1A, a comparison voltage is input to the positive phase end of the resistor R7, the output end of the comparison operational amplifier unit U1A outputs a high level or a low level, the output end is connected with the grid electrode of the MOS tube Q1, the source electrode of the MOS tube Q1 is connected with a module supply voltage VCC, and the drain electrode is grounded.
Description
Technical Field
The invention relates to the field of LED power supplies, in particular to a bridgeless PFC input undervoltage protection circuit.
Background
With the development of technology and society, the application field of high-power LED driving power supply is wider and wider, and the development trend of small volume, high efficiency, high frequency and high power density is presented, in order to meet the global general sales advantage, the input range of the ultra-high-power supply is generally designed to be 120V-277Vac, so that the loss and heat of the rectifier bridge are very large if the conventional rectifier bridge PFC scheme is adopted when the high-power is input to 120 VAc, and the problems of increasing the product volume, the radiator and the cost are solved. If the bridgeless PFC scheme with the new architecture is adopted, the alternating current input is directly boosted by the bridgeless PFC, the loss of the rectifier bridge can be reduced while the cost is not increased, the purposes of small volume, high power density and high efficiency can be really realized, and the normal input range of the product is in the normal operation range of 120-277 Vac. However, in some severe conditions, the power grid voltage in the polar region sometimes falls below 120V ac, which greatly increases the power stress and sometimes causes damage, and an input undervoltage protection circuit is usually added, so that the main power circuit of the power supply is closed when the input is below 110V, the power supply is effectively protected, and when the input exceeds 110V, the input undervoltage circuit recognizes that the input is in a normal range and starts the power supply to work normally. For conventional PFC power supplies with a rectifier bridge, the input undervoltage protection samples are typically up-sampled from the CBB capacitor after the rectifier bridge. The input undervoltage protection can only sample alternating current signals for bridge-free PFC adopting a new structure, and the input undervoltage protection can be rectified by a diode.
Disclosure of Invention
In order to solve the problems, the technical scheme provides a bridgeless PFC input under-voltage protection circuit which can realize bridgeless PFC application and realize high-precision input under-voltage protection.
In order to achieve the above purpose, the technical scheme is as follows:
the bridgeless PFC input undervoltage protection circuit comprises an L-phase signal end and an N-phase signal end;
the positive phase end of the differential operational amplifier unit U1B is connected with the L-phase signal end, the negative phase end of the differential operational amplifier unit U1B is connected with the N-phase signal end, and the output end of the differential operational amplifier unit U1B outputs half-wave voltage;
the output end of the differential operational amplifier unit U1B is sequentially connected with a diode D1 and a resistor R7, the resistor R7 is connected with the negative phase end of the comparison operational amplifier unit U1A, a comparison voltage is input to the positive phase end of the resistor R7, the output end of the comparison operational amplifier unit U1A outputs a high level or a low level, the output end is connected with the grid electrode of the MOS tube Q1, the source electrode of the MOS tube Q1 is connected with a module supply voltage VCC, and the drain electrode is grounded.
In some embodiments, the L-phase signal end is connected to the differential operational amplifier unit U1B through a resistor R3 and a resistor R4 in sequence, and the N-phase signal end is connected to the differential operational amplifier unit U1B through a resistor R1 and a resistor R2 in sequence.
In some embodiments, the resistor R4 is further grounded through a resistor RS and a capacitor C1, respectively.
In some embodiments, a resistor R6 and a capacitor C2 are connected between the negative phase terminal and the output terminal of the differential operational amplifier unit U1B, respectively.
In some embodiments, the resistor R7 is further connected to ground through a capacitor C3, and the resistor R7 is further connected to the output terminal of the comparison operational amplifier unit U1A through a capacitor C4.
In some embodiments, the output end of the comparison operational amplifier unit U1A is connected to the gate of the MOS transistor Q1 through a resistor R8, and the resistor R8 is further grounded through a resistor R9.
The beneficial effects of the application are that:
the AC L and N phases are directly and differentially sampled and input into the operational amplifier, the voltages of L and N which float relatively are converted into the attenuated accurate voltages to the ground after the operational amplifier attenuates and operation is carried out, the undervoltage protection point errors are small when the output light load and the full load are carried out accurately through the comparison operation of a later-stage circuit, and the operational amplifier is well embodied in the bridge-free PFC circuit of some ultra-high power projects.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the description of the embodiments will be briefly described below.
Fig. 1 is a schematic structural view of an embodiment of the present invention.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects solved by the invention more clear, the invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Referring to fig. 1, a bridgeless PFC input undervoltage protection circuit is characterized by comprising an L-phase signal terminal and an N-phase signal terminal;
the positive phase end of the differential operational amplifier unit U1B is connected with the L-phase signal end, the negative phase end of the differential operational amplifier unit U1B is connected with the N-phase signal end, and the output end of the differential operational amplifier unit U1B outputs half-wave voltage;
the output end of the differential operational amplifier unit U1B is sequentially connected with a diode D1 and a resistor R7, the resistor R7 is connected with the negative phase end of the comparison operational amplifier unit U1A, a comparison voltage is input to the positive phase end of the resistor R7, the output end of the comparison operational amplifier unit U1A outputs a high level or a low level, the output end is connected with the grid electrode of the MOS tube Q1, the source electrode of the MOS tube Q1 is connected with a module supply voltage VCC, and the drain electrode is grounded.
When the power supply starts up, the auxiliary power supply starts up, VCC is sequentially output to the power circuit module, 12V is output to the control circuit and the input undervoltage protection circuit, related circuits such as the bridgeless PFC circuit and the DC/DC conversion circuit are sequentially operated, input undervoltage protection directly samples alternating current L and N signals, voltage between L and N can be accurately acquired by adopting a differential input mode, an AC_L signal of L phase is connected in series with R5 and C1 through resistors R3 and R4 and then is sent to a P5 pin (positive end input) of the operational amplifier U1B after being voltage-dividing and filtered, and an N phase is connected with a P6 pin (negative end input) of the U1B through the AC_N signal after being connected in series with R6 and C2 through resistors R1 and R2. At this time, the output voltage signal of the pin P7 of U1B should be (voltage between L phase and N phase) (R6/(r1+r2)), the voltage between L phase and N phase is converted into the accurate ground voltage after the attenuation of the operational amplifier by the above sampling conversion, the pin P7 of U1B outputs a half-wave dc signal, which is rectified by the diodes D1 and R7 with low VF value, the C3 filters to form a smooth dc signal, which is sent to the pin P2 (negative input) (i.e., VB signal) of the operational amplifier U1A, and compared with the reference voltage of pin 3 (negative input) 2.5V of the operational amplifier U1A, if the input voltage is higher than 110Vac, the voltage is higher than 2.5V, the voltage is compared with the voltage of pin P3 of U1A with 2.5V of the operational amplifier U1A, the pin 1 of U1A outputs a low level, the pin 1 of U1A is sent to the pin 1 of the MOS transistor Q1 after the voltage is divided by the resistors R8 and R9, the main power circuit VCC is not turned on, and the voltage is sent to the pin Q1 after the voltage is lower than the voltage of the pin V1A 2.5V is higher than the voltage of the operational amplifier U1A, and the voltage is sent to the pin Q1 after the voltage is higher than the voltage of the pin 1V 1 is higher than the voltage of the pin 2.5V, and the voltage is not compared with the pin 1V 1 after the voltage is passed through the pin 1V 1 is passed through the voltage of the resistor 2.2. The capacitor C4 has a feedback effect of return difference, and prevents the power supply from repeatedly operating to stop jumping back and forth when the input is at the 110Vac critical point.
In this embodiment, the L-phase signal end is connected to the differential operational amplifier unit U1B through a resistor R3 and a resistor R4 in sequence, and the N-phase signal end is connected to the differential operational amplifier unit U1B through a resistor R1 and a resistor R2 in sequence.
In this embodiment, the resistor R4 is further grounded through a resistor RS and a capacitor C1, respectively.
In this embodiment, a resistor R6 and a capacitor C2 are respectively connected between the negative phase end and the output end of the differential operational amplifier unit U1B.
In this embodiment, the resistor R7 is further grounded through a capacitor C3, and the resistor R7 is further connected to the output terminal of the comparison operational amplifier unit U1A through a capacitor C4.
In this embodiment, the output end of the comparison operational amplifier unit U1A is connected to the gate of the MOS transistor Q1 through a resistor R8, and the resistor R8 is further grounded through a resistor R9.
Based on the above circuit, the method further comprises the following steps:
when the power-on is started, the auxiliary power supply works, the output VCC is respectively sent to the bridgeless PFC and the power circuit, the 12V is simultaneously sent to the control circuit and the input undervoltage protection circuit IC, the related circuits start to work in sequence, the output is normally carried, the input undervoltage protection adopts alternating current sampling, the differential input mode, the AC_L signal from the L phase is connected with the R5 in series through the resistors R3 and R4, the C1 is filtered and then sent to the 5 pin of the U1 operational amplifier, the AC_N signal from the N phase is connected with the R6 and C2 in series through the resistors R1 and R2 and then sent to the 6 pin of the U1B operational amplifier, at the moment, the voltage between the L phase and the N phase can be accurately acquired due to differential sampling, after the attenuation operation of the sampled signal is carried out by the U1B operational amplifier, the floating voltage of the L phase and the N phase relative ground is converted into the accurate voltage to the ground, the output voltage of the pin 7 of the U1B is half-wave DC voltage, the voltage is rectified by a diode D1 with a low VF value, R7 and C3 are filtered to form a smooth direct current signal, the direct current signal is sent to the pin 2 of the U1A (negative end input of the operational amplifier), after being compared with the reference signal of the pin 3 of the U1A (positive end input of the operational amplifier) with 2.5V, if the input voltage L and N is greater than 110VAc, the voltage of the pin 2 of the U1A is greater than 2.5V through the circuit sampling operation, the voltage of the pin 2 (negative end) is compared with the voltage of the pin 3 of the U1 (positive end) with 2.5V, the pin 1 of the U1A outputs a low level, and the low level is sent to the pin 1 of the Q1 after being divided by the resistor R8, the Q1 is not conducted, and the main power circuit VCC is not affected, and normal work is continued. When the input voltage is lower than 110V ac, after the sampling operation of the circuit, the voltage of the pin 2 (negative end of the operational amplifier) of the U1A is lower than 2.5V, the voltage of the pin 1 of the U1A is output to a high level after the voltage of the pin 2 of the U1A is compared with the voltage of the pin 3 (positive end of the operational amplifier) of the U1A, the high level is divided by R8 and R9 and then is sent to the driving pin of the Q1, so that the Q1 is conducted, the power supply VCC of the main power circuit is pulled down by the resistor R10, and the main power circuit stops working. If the input voltage is near 110VAc, the C4 capacitor has return feedback effect, and the phenomenon that the main power circuit stops working when working does not occur.
The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the scope of the present application, but other principles and basic structures are the same or similar to the present application.
Claims (1)
1. The bridgeless PFC input undervoltage protection circuit is characterized by comprising an L-phase signal end and an N-phase signal end;
the positive phase end of the differential operational amplifier unit U1B is connected with the L-phase signal end, the negative phase end of the differential operational amplifier unit U1B is connected with the N-phase signal end, and the output end of the differential operational amplifier unit U1B outputs half-wave voltage;
the output end of the differential operational amplifier unit U1B is connected with one end of a diode D1, the other end of the diode D1 is connected with one end of a resistor R7, the other end of the resistor R7 is connected with the negative phase end of the comparison operational amplifier unit U1A, a comparison voltage is input to the positive phase end of the comparison operational amplifier unit U1A, the output end of the comparison operational amplifier unit U1A outputs a high level or a low level, the output end is connected with the grid electrode of a MOS tube Q1, the source electrode of the MOS tube Q1 is connected with a module power supply voltage VCC, and the drain electrode is grounded; the module power supply voltage VCC is respectively sent to the bridgeless PFC and the power circuit;
the L-phase signal end is connected with the positive phase end of the differential operational amplifier unit U1B through a resistor R3 and a resistor R4 in sequence, and the N-phase signal end is connected with the negative phase end of the differential operational amplifier unit U1B through a resistor R1 and a resistor R2 in sequence;
the connection point of the resistor R4 and the positive end of the differential operational amplifier unit U1B is grounded through a resistor R5 and a capacitor C1 respectively;
a resistor R6 and a capacitor C2 are respectively connected between the negative phase end and the output end of the differential operational amplifier unit U1B;
the other end of the resistor R7 is grounded through a capacitor C3, and the other end of the resistor R7 is connected with the output end of the comparison operational amplifier unit U1A through a capacitor C4;
the output end of the comparison operational amplifier unit U1A is connected with the grid electrode of the MOS tube Q1 through a resistor R8, and the grid electrode of the MOS tube Q1 is grounded through a resistor R9;
when the power-on is started, the auxiliary power supply works, the output VCC is respectively sent to the bridgeless PFC and the power circuit, the 12V is simultaneously sent to the control circuit and the input undervoltage protection circuit IC, the related circuits start to work in sequence, the output is normally carried, the input undervoltage protection adopts an alternating current sampling and differential input mode, an AC_L signal from L phases is connected with R5 in series through resistors R3 and R4, and C1 in a pressure dividing and filtering mode and then is sent to the positive phase end of the differential operational amplifier unit U1B, an AC_N signal from N phases is connected with R6 and C2 in series through resistors R1 and R2 and then is sent to the negative phase end of the differential operational amplifier unit U1B, at the moment, the voltage between the L phases and the N phases can be accurately acquired due to differential sampling, after the attenuation operation of the sampled signals by the differential operational amplifier unit U1B, the floating voltage of the L phases and N phases relative ground is converted into accurate voltage to the ground, the output voltage of the output end of the differential operational amplifier unit U1B is half-wave DC voltage, the half-wave DC voltage is rectified by a diode D1 with a low VF value, R7 and C3 are filtered to form a smooth direct current signal, the direct current signal is sent to the negative end input of the comparison operational amplifier unit U1A and is compared with a reference signal with 2.5V input by the positive end of the comparison operational amplifier unit U1A, if the input voltage L and N is greater than 110VAc, the voltage of the negative end of the comparison operational amplifier unit U1A is greater than 2.5V through circuit sampling operation, the negative end is compared with the positive end 2.5V of the U1, the output end of the comparison operational amplifier unit U1A outputs a low level, the low level is divided by a resistor R8 and then sent to the driving pin of the MOS tube Q1, the MOS tube Q1 is not conducted, and the main power circuit is not affected, so that normal VCC operation is continued; when the input voltage is lower than 110V ac, the negative phase end of the comparison operational amplifier unit U1A is lower than 2.5V after the circuit sampling operation, the output end of the comparison operational amplifier unit U1A outputs high level after the negative phase end of the comparison operational amplifier unit U1A is compared with the positive phase end of the comparison operational amplifier unit U1A by 2.5V, the high level is divided by R8 and R9 and then is sent to the driving pin of the MOS tube Q1, the MOS tube Q1 is conducted, the power supply VCC of the main power circuit is pulled down by the resistor R10, the main power circuit stops working, and if the input voltage is near 110V ac, the phenomenon that the main power circuit stops working due to the feedback effect of return difference of the C4 capacitor does not occur.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311721924.6A CN117410934B (en) | 2023-12-14 | 2023-12-14 | Bridgeless PFC input undervoltage protection circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311721924.6A CN117410934B (en) | 2023-12-14 | 2023-12-14 | Bridgeless PFC input undervoltage protection circuit |
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| Publication Number | Publication Date |
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| CN117410934A CN117410934A (en) | 2024-01-16 |
| CN117410934B true CN117410934B (en) | 2024-04-12 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014042433A (en) * | 2012-08-23 | 2014-03-06 | Toyota Motor Corp | Bridgeless pfc converter with average current mode control |
| CN205453099U (en) * | 2015-12-25 | 2016-08-10 | 广州金升阳科技有限公司 | Sampling circuit and mistake, undervoltage protection control circuit |
| WO2018214952A1 (en) * | 2017-05-25 | 2018-11-29 | 中兴通讯股份有限公司 | Voltage sampling circuit and circuit system |
| CN115986677A (en) * | 2022-12-16 | 2023-04-18 | 东方电子股份有限公司 | Alternating current power supply under-voltage switching circuit |
| CN115995954A (en) * | 2023-03-22 | 2023-04-21 | 广东汇芯半导体有限公司 | PFC intelligent module |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7164591B2 (en) * | 2003-10-01 | 2007-01-16 | International Rectifier Corporation | Bridge-less boost (BLB) power factor correction topology controlled with one cycle control |
-
2023
- 2023-12-14 CN CN202311721924.6A patent/CN117410934B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014042433A (en) * | 2012-08-23 | 2014-03-06 | Toyota Motor Corp | Bridgeless pfc converter with average current mode control |
| CN205453099U (en) * | 2015-12-25 | 2016-08-10 | 广州金升阳科技有限公司 | Sampling circuit and mistake, undervoltage protection control circuit |
| WO2018214952A1 (en) * | 2017-05-25 | 2018-11-29 | 中兴通讯股份有限公司 | Voltage sampling circuit and circuit system |
| CN115986677A (en) * | 2022-12-16 | 2023-04-18 | 东方电子股份有限公司 | Alternating current power supply under-voltage switching circuit |
| CN115995954A (en) * | 2023-03-22 | 2023-04-21 | 广东汇芯半导体有限公司 | PFC intelligent module |
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| Publication number | Publication date |
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| CN117410934A (en) | 2024-01-16 |
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