CN203026918U - Input over-voltage protection circuit of smart grid terminal power supply - Google Patents
Input over-voltage protection circuit of smart grid terminal power supply Download PDFInfo
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- CN203026918U CN203026918U CN 201220645876 CN201220645876U CN203026918U CN 203026918 U CN203026918 U CN 203026918U CN 201220645876 CN201220645876 CN 201220645876 CN 201220645876 U CN201220645876 U CN 201220645876U CN 203026918 U CN203026918 U CN 203026918U
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Abstract
The utility model provides an input over-voltage protection circuit of a smart grid terminal power supply, and relates to the field of smart grid terminal switch power supplies. The circuit comprises an alternating current power supply input end, a rectifying circuit, an input smoothing capacitor, a switch tube protection circuit, a switch control circuit, a switch tube and a transformer, wherein the switch tube circuit comprises a precise voltage-stabilizing source TL431, a PNP triode, a filter capacitor, a current limiting resistor, a power supply resistor and some sampling resistors. When the input voltage of a switch power supply exceeds upper limit voltage, the precise voltage-stabilizing source TL431 and the PNP triode in the switch tube protection circuit are in conducting states, the direct current power supply voltage of the switch control circuit is reduced, the switch control circuit stops working, and the voltage of the switch tube is further reduced. According to the input over-voltage protection circuit, a switch tube with a very high withstand voltage value is not required to be selected under the condition that the switch power supply is at high input voltage, so that the total cost of devices is lowered, and the size of the power supply is reduced effectively.
Description
Technical field
The utility model relates to intelligent grid limit switch field of power supplies, relates in particular to a kind of protection circuit against input over-voltage of the power supply such as acquisition terminal, three-phase load control terminal in three-phase intelligent ammeter, three-phase set.
Background technology
The operation principle of Switching Power Supply is: at first, the alternating voltage input is eliminated the electrical network interference through the input line filter and is become direct voltage by rectifying and wave-filtering; Then, by high-frequency PWM (Pul se-Width Modulation pulse width modulation) Signal-controlled switch pipe, direct voltage is added to the primary coil of switch transformer; Moreover switch transformer secondary coil output high-frequency ac voltage is through the rectifying and wave-filtering supply load; Simultaneously, output feeds back to control circuit by feedback circuit, controls the PWM duty ratio, to satisfy the requirement of stable output.In order to prevent Switching Power Supply generation overvoltage, overcurrent short-circuit state, Switching Power Supply generally also need have protective circuit, makes Switching Power Supply quit work to protect load and power supply itself.Wherein the switching speed of power supply switch tube is very fast, depends on the PWM of front oscillating circuit output, is the major part of Switching Power Supply, is also the rapid wear device.
380V line voltage in intelligent grid is because the reasons such as load, external interference, Voltage unbalance can make line voltage constantly raise, can approach when extreme and exchange 600V, thereby the requirement to switching tube in Switching Power Supply is very high, will select at least the above switching tube of withstand voltage 1200V.Yet the switching tube price of 1200V is very high, and not general.If adopt two switching tube series connection, both be unfavorable for miniaturization, cost also increases thereupon simultaneously.Therefore need a kind of solution of Switching Power Supply cheaply.
The utility model content
In order to make Switching Power Supply needn't select the withstand voltage switching tube more than 1200V at least under the condition of high input voltage, effectively reduce costs, be beneficial to miniaturization, the utility model proposes a kind of intelligent grid terminal electrical source input overvoltage protection circuit.
Technical solutions of the utility model are as follows:
A kind of intelligent grid terminal electrical source input overvoltage protection circuit comprises ac power input end, rectification circuit, input smoothing capacitor, switching tube protection circuit, ON-OFF control circuit, switching tube, transformer;
Described input smoothing capacitor is connected in parallel between the dc output end of described rectification circuit; The input of described switching tube protection circuit and described input smoothing capacitor are connected in parallel, and the output of described switching tube protection circuit is connected with the direct current supply voltage of described ON-OFF control circuit; The output of described ON-OFF control circuit is connected with the input of described switching tube; The output of described switching tube is connected with described transformer;
Described rectification circuit is used for alternating current is transformed into direct current; described input smoothing capacitor is used for the ripple of the described Output Voltage in Rectified Circuits of filtering; described ON-OFF control circuit is used for realizing the conducting of described switching tube or the control of closing; described transformer is used for the described direct current after smothing filtering is transformed into high-frequency alternating current, and described switching tube protection circuit affects the operating state of described ON-OFF control circuit and the voltage of described switching tube by the control on dc power supply described in described ON-OFF control circuit.
The input of described rectification circuit is the alternating current that described ac power input end is supplied with, and described rectification circuit is the single-phase full-wave rectifer circuit that is connected and composed by four diode bridge types.
Described switching tube protection circuit comprises precision voltage regulator TL431, positive-negative-positive triode, filter capacitor, current-limiting resistance, supplying resistance, the first sampling resistor, the second sampling resistor, the 5th resistance; Be connected with the negative electrode of described precision voltage regulator TL431 after the described current-limiting resistance of base stage series connection of described positive-negative-positive triode, collector electrode is connected with the negative pole of described input smoothing capacitor, and emitter is connected with the dc power supply of described ON-OFF control circuit; The anode of described precision voltage regulator TL431 is connected with the described collector electrode of described positive-negative-positive triode, be connected with the described dc power supply of described ON-OFF control circuit after the described supplying resistance of negative electrode series connection, be connected with the described anode of described precision voltage regulator TL431 after described the second sampling resistor of reference edge series connection; Described filter capacitor and described the second sampling resistor are connected in parallel; One end of described the first sampling resistor is connected with the positive pole of described input smoothing capacitor, and the other end is connected with the described reference edge of described precision voltage regulator TL431; One end of described the 5th resistance is connected with described supplying resistance, and the other end is connected with the described positive pole of described input smoothing capacitor.
Described ON-OFF control circuit is selected pwm chip.
Described switching tube adopts the field effect transistor of N raceway groove; The input of the corresponding described switching tube of the grid of the field effect transistor of described N raceway groove is connected with the output of described ON-OFF control circuit; The source electrode of the field effect transistor of described N raceway groove is connected with the described negative pole of described input smoothing capacitor; The output of the corresponding described switching tube of the drain electrode of the field effect transistor of described N raceway groove is connected with an end of described transformer.
The primary coil of described transformer comprises iron core and coil; One end of the described primary coil of described transformer is connected with the output of described switching tube, and the other end is connected with the described positive pole of described input smoothing capacitor.
The utility model has adopted a kind of intelligent grid terminal electrical source input overvoltage protection circuit; when the Switching Power Supply input voltage surpasses upper voltage limit; conducting by precision voltage regulator TL431 in circuit and positive-negative-positive triode; drag down the voltage of ON-OFF control circuit dc power supply; ON-OFF control circuit quits work, and then switch tube voltage is lowered.The utility model can make Switching Power Supply under the condition of high input voltage, as long as the switching tube that the selection withstand voltage is 900V or 1000V just can satisfy instructions for use, needn't the very expensive uncurrent withstand voltage of purchasing price be the above switching tube of 1200V, reduced the device total cost, and circuit is simple and reliable, can reduce power volume.
Description of drawings
Fig. 1 is the intelligent grid terminal electrical source input overvoltage protection circuit schematic diagram that the utility model embodiment provides.
Embodiment
Further illustrate the technical solution of the utility model below in conjunction with accompanying drawing and by embodiment.
Fig. 1 is the intelligent grid terminal electrical source input overvoltage protection circuit schematic diagram that the utility model embodiment provides.
As shown in Figure 1, a kind of intelligent grid terminal electrical source input overvoltage protection circuit comprises ac power input end L, N, rectification circuit 1, input smoothing capacitor C1, switching tube protection circuit 2, pwm chip, the field effect transistor Q2 of N raceway groove, transformer T1.
Rectification circuit 1 is the single-phase full-wave rectifer circuit that is connected and composed by four diode D1-D4 bridge types, and what its input was inputted is the alternating current of being supplied with by AC power, and what its output was exported is direct current.
The positive pole of input smoothing capacitor C1 connects the dc output end W1 of rectification circuit 1, and negative pole connects the dc output end W2 of rectification circuit 1, is used for the ripple of filtering Output Voltage in Rectified Circuits.Smoothing capacitor C1 has the energy storage effect due to input, can the storage area energy when supply voltage raises, and when reducing, supply voltage can release energy, can play the effect of flat ripple.
Switching tube protection circuit comprises TL431 precision voltage regulator A1, positive-negative-positive triode Q1, filter capacitor C2, current-limiting resistance R3, supplying resistance R4, the first sampling resistor R1, the second sampling resistor R2, the 5th resistance R 5.Be connected with the negative electrode of TL431 precision voltage regulator A1 after the base stage series limiting resistor R3 of positive-negative-positive triode Q1, collector electrode is connected with the negative pole of input smoothing capacitor C1, and emitter is connected with the dc power supply VCC of ON-OFF control circuit.The anode of TL431 precision voltage regulator A1 is connected with the collector electrode of positive-negative-positive triode Q1, be connected with the dc power supply VCC of ON-OFF control circuit after negative electrode series-fed resistance R 4, be connected with the anode of TL431 precision voltage regulator A1 after reference edge series connection the second sampling resistor R2.Filter capacitor C2 and the second sampling resistor R2 are connected in parallel.The end of the first sampling resistor R1 is connected with the positive pole of input smoothing capacitor C1, and the other end is connected with the reference edge of TL431 precision voltage regulator A1.One end of the 5th resistance R 5 is connected with supplying resistance R4, and the other end is connected with the positive pole of input smoothing capacitor C1.Wherein current-limiting resistance R3 is used for adjusting the base current of positive-negative-positive triode Q1.The first sampling resistor R1 in switching tube protection circuit and the resistance size of the second sampling resistor R2 will be according to input the work upper voltage limit when normal and the withstand voltage of switching tube Q2 design.
The dc power supply VCC of pwm chip is connected with the emitter of positive-negative-positive triode Q1, and the output of pwm chip is connected with the field effect transistor Q2 of N raceway groove.Pulse duration in PWM is the time of output high level in one-period.Pwm chip is by the certain pwm pulse control signal of output, and conducting and the cut-off state of the field effect transistor Q2 of N raceway groove are controlled.
The grid of the field effect transistor of N raceway groove is connected with the output of pwm chip, and its source electrode is connected with the negative pole of input smoothing capacitor C1, and its drain electrode is connected with an end of the primary coil of transformer T1.
The primary coil of transformer T1 comprises iron core and coil, and an end of transformer T1 primary coil is connected with the drain electrode of the field effect transistor Q2 of N raceway groove, and the other end is connected with the positive pole of input smoothing capacitor C1.The induction that intercouples of the primary coil of transformer T1 and secondary coil is transformed into high-frequency alternating current with the direct current after smothing filtering, and plays the effect of Switching Power Supply with the isolation of input electrical network.
Switching tube protection circuit affects the operating state of pwm chip by the control on ON-OFF control circuit dc power supply VCC, thereby causes that the voltage between switching tube Q2 drain electrode and source electrode changes.When the Switching Power Supply input voltage does not surpass upper voltage limit; in switching tube protection circuit, positive-negative-positive triode Q1 is cut-off state; the pwm chip normal operation; by exporting certain pwm pulse control signal; conducting and cut-off state to switching tube Q2 are controlled; and then direct current is added on the primary coil of transformer T1, with the secondary coil induction that intercouples, the direct current after smothing filtering is transformed into high-frequency alternating current.Voltage between this moment switching tube Q2 drain electrode and source electrode equals to input voltage on smoothing capacitor C1 and the reflected voltage sum of transformer T1 primary coil.When the input voltage of Switching Power Supply surpasses upper voltage limit, by the dividing potential drop of the first sampling resistor R1 and the second sampling resistor R2 in switch protecting circuit, make voltage on the second sampling resistor R2 higher than 2.5V.Because the reference voltage of TL431 precision voltage regulator A1 is 2.5V, TL431 precision voltage regulator A1 is conducting state, also conducting thereupon of positive-negative-positive triode Q1 when the input voltage of Switching Power Supply surpasses upper voltage limit.When in switching tube protection circuit during positive-negative-positive triode Q1 conducting, the dc power supply VCC voltage of pwm chip will be dragged down, and chip quits work.Because the grid of switching tube Q2 is connected with the output of pwm chip, when pwm chip quits work, switching tube Q2 also will end and not work, voltage between switching tube Q2 drain electrode at this moment and source electrode only is the voltage on input smoothing capacitor C1, has reduced like this voltage stress of switching tube Q2.When input voltage recovers normal again, Switching Power Supply also will be recovered normal operation.
The technical solution of the utility model has proposed a kind of intelligent grid terminal electrical source input overvoltage protection circuit; when the Switching Power Supply input voltage surpasses upper voltage limit; conducting by precision voltage regulator TL431 in circuit and positive-negative-positive triode; drag down ON-OFF control circuit dc power supply voltage; ON-OFF control circuit quits work, and then the voltage between switching tube drain electrode and source electrode is lowered.The utility model can solve Switching Power Supply switching tube under the condition of high input voltage and select difficult problem, and circuit is simple and reliable, can reduce power volume, effectively reduce the device total cost.
The above; it is only the better embodiment of the utility model; but protection range of the present utility model is not limited to this; anyly be familiar with the people of this technology in the disclosed technical scope of the utility model; the variation that can expect easily or replacement are within all should being encompassed in protection range of the present utility model.Therefore, protection range of the present utility model should be as the criterion with the protection range of claim.
Claims (6)
1. intelligent grid terminal electrical source input overvoltage protection circuit is characterized in that:
Described electrical source input overvoltage protection circuit comprises ac power input end, rectification circuit, input smoothing capacitor, switching tube protection circuit, ON-OFF control circuit, switching tube, transformer;
Described input smoothing capacitor is connected in parallel between the dc output end of described rectification circuit; The input of described switching tube protection circuit and described input smoothing capacitor are connected in parallel, and the output of described switching tube protection circuit is connected with the direct current supply voltage of described ON-OFF control circuit; The output of described ON-OFF control circuit is connected with the input of described switching tube; The output of described switching tube is connected with described transformer;
Described rectification circuit is used for alternating current is transformed into direct current; described input smoothing capacitor is used for the ripple of the described Output Voltage in Rectified Circuits of filtering; described ON-OFF control circuit is used for realizing the conducting of described switching tube or the control of closing; described transformer is used for the described direct current after smothing filtering is transformed into high-frequency alternating current, and described switching tube protection circuit affects the operating state of described ON-OFF control circuit and the voltage of described switching tube by the control on dc power supply described in described ON-OFF control circuit.
2. intelligent grid terminal electrical source input overvoltage protection circuit according to claim 1; it is characterized in that; the input of described rectification circuit is the alternating current that described ac power input end is supplied with, and described rectification circuit is the single-phase full-wave rectifer circuit that is connected and composed by four diode bridge types.
3. intelligent grid terminal electrical source input overvoltage protection circuit according to claim 1, it is characterized in that, described switching tube protection circuit comprises precision voltage regulator TL431, positive-negative-positive triode, filter capacitor, current-limiting resistance, supplying resistance, the first sampling resistor, the second sampling resistor, the 5th resistance; Be connected with the negative electrode of described precision voltage regulator TL431 after the described current-limiting resistance of base stage series connection of described positive-negative-positive triode, collector electrode is connected with the negative pole of described input smoothing capacitor, and emitter is connected with the described dc power supply of described ON-OFF control circuit; The anode of described precision voltage regulator TL431 is connected with the described collector electrode of described positive-negative-positive triode, be connected with the described dc power supply of described ON-OFF control circuit after the described supplying resistance of negative electrode series connection, be connected with the described anode of described precision voltage regulator TL431 after described the second sampling resistor of reference edge series connection; Described filter capacitor and described the second sampling resistor are connected in parallel; One end of described the first sampling resistor is connected with the positive pole of described input smoothing capacitor, and the other end is connected with the described reference edge of described precision voltage regulator TL431; One end of described the 5th resistance is connected with described supplying resistance, and the other end is connected with the described positive pole of described input smoothing capacitor.
4. intelligent grid terminal electrical source input overvoltage protection circuit according to claim 1, is characterized in that, described ON-OFF control circuit is selected pwm chip.
5. intelligent grid terminal electrical source input overvoltage protection circuit according to claim 1, is characterized in that, described switching tube adopts the field effect transistor of N raceway groove; The input of the corresponding described switching tube of the grid of the field effect transistor of described N raceway groove is connected with the output of described ON-OFF control circuit; The source electrode of the field effect transistor of described N raceway groove is connected with the described negative pole of described input smoothing capacitor; The output of the corresponding described switching tube of the drain electrode of the field effect transistor of described N raceway groove is connected with an end of described transformer.
6. intelligent grid terminal electrical source input overvoltage protection circuit according to claim 1, is characterized in that, the primary coil of described transformer comprises iron core and coil; One end of the described primary coil of described transformer is connected with the output of described switching tube, and the other end is connected with the described positive pole of described input smoothing capacitor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220645876 CN203026918U (en) | 2012-11-29 | 2012-11-29 | Input over-voltage protection circuit of smart grid terminal power supply |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220645876 CN203026918U (en) | 2012-11-29 | 2012-11-29 | Input over-voltage protection circuit of smart grid terminal power supply |
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| CN203026918U true CN203026918U (en) | 2013-06-26 |
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| CN 201220645876 Expired - Fee Related CN203026918U (en) | 2012-11-29 | 2012-11-29 | Input over-voltage protection circuit of smart grid terminal power supply |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103683207A (en) * | 2013-12-23 | 2014-03-26 | 北京易艾斯德科技有限公司 | Under-voltage and over-voltage protection circuit for power supply circuit |
| CN104466914A (en) * | 2013-12-11 | 2015-03-25 | 成都芯源系统有限公司 | Short circuit protection circuit, switching power supply and protection method |
| WO2015051688A1 (en) * | 2013-10-09 | 2015-04-16 | 珠海格力电器股份有限公司 | Protective circuit for input voltage of switch power source |
| CN106684814A (en) * | 2017-03-23 | 2017-05-17 | 广州市爱浦电子科技有限公司 | High-precision normal-shock switch power output overvoltage protection circuit |
| CN107658857A (en) * | 2017-09-21 | 2018-02-02 | 南京林洋电力科技有限公司 | A kind of switch power over-voltage protection circuit and method |
| CN108964436A (en) * | 2017-05-27 | 2018-12-07 | 许继集团有限公司 | A kind of Switching Power Supply start-up circuit |
| CN109038529A (en) * | 2018-08-10 | 2018-12-18 | 维沃移动通信有限公司 | A kind of overvoltage crowbar, charger and electronic equipment |
| CN110635679A (en) * | 2018-06-22 | 2019-12-31 | 三星电机株式会社 | Voltage control circuit |
| CN114126152A (en) * | 2022-01-26 | 2022-03-01 | 杭州易会通科技有限公司 | Integrated circuit and driving circuit for three-phase alternating current commercial power LED tunnel lamp |
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- 2012-11-29 CN CN 201220645876 patent/CN203026918U/en not_active Expired - Fee Related
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2015051688A1 (en) * | 2013-10-09 | 2015-04-16 | 珠海格力电器股份有限公司 | Protective circuit for input voltage of switch power source |
| CN104577993A (en) * | 2013-10-09 | 2015-04-29 | 珠海格力电器股份有限公司 | Input voltage protection circuit of switching power supply |
| CN104577993B (en) * | 2013-10-09 | 2018-11-09 | 珠海格力电器股份有限公司 | Switching Power Supply input voltage protection circuit |
| CN104466914A (en) * | 2013-12-11 | 2015-03-25 | 成都芯源系统有限公司 | Short circuit protection circuit, switching power supply and protection method |
| CN103683207A (en) * | 2013-12-23 | 2014-03-26 | 北京易艾斯德科技有限公司 | Under-voltage and over-voltage protection circuit for power supply circuit |
| CN103683207B (en) * | 2013-12-23 | 2017-03-15 | 北京易艾斯德科技有限公司 | Under-voltage overvoltage crowbar for power circuit |
| CN106684814A (en) * | 2017-03-23 | 2017-05-17 | 广州市爱浦电子科技有限公司 | High-precision normal-shock switch power output overvoltage protection circuit |
| CN108964436A (en) * | 2017-05-27 | 2018-12-07 | 许继集团有限公司 | A kind of Switching Power Supply start-up circuit |
| CN107658857A (en) * | 2017-09-21 | 2018-02-02 | 南京林洋电力科技有限公司 | A kind of switch power over-voltage protection circuit and method |
| CN110635679A (en) * | 2018-06-22 | 2019-12-31 | 三星电机株式会社 | Voltage control circuit |
| CN109038529A (en) * | 2018-08-10 | 2018-12-18 | 维沃移动通信有限公司 | A kind of overvoltage crowbar, charger and electronic equipment |
| CN114126152A (en) * | 2022-01-26 | 2022-03-01 | 杭州易会通科技有限公司 | Integrated circuit and driving circuit for three-phase alternating current commercial power LED tunnel lamp |
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Granted publication date: 20130626 Termination date: 20151129 |