CN113644816B - Constant current starting circuit with ultra-wide input voltage range - Google Patents
Constant current starting circuit with ultra-wide input voltage range Download PDFInfo
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- CN113644816B CN113644816B CN202110813361.8A CN202110813361A CN113644816B CN 113644816 B CN113644816 B CN 113644816B CN 202110813361 A CN202110813361 A CN 202110813361A CN 113644816 B CN113644816 B CN 113644816B
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- 238000010277 constant-current charging Methods 0.000 claims abstract description 71
- 230000005669 field effect Effects 0.000 claims description 22
- 239000003990 capacitor Substances 0.000 claims description 10
- 230000000087 stabilizing effect Effects 0.000 claims description 3
- 238000000034 method Methods 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 238000007600 charging Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 230000008859 change Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
Classifications
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- 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
- H02M1/32—Means for protecting converters other than automatic disconnection
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/34—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering
- H02J7/345—Parallel operation in networks using both storage and other dc sources, e.g. providing buffering using capacitors as storage or buffering devices
-
- 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
- H02M1/36—Means for starting or stopping converters
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention discloses a constant current starting circuit with ultra-wide input voltage range, which comprises three parts: the constant-current charging circuit, the constant-current charging turn-off circuit for turning off the constant-current charging circuit and the transformer auxiliary power supply circuit. The input end of the constant current charging circuit is connected with the externally applied input voltage, and the output end of the constant current charging circuit is connected with the power supply end of the switching power supply IC chip; the input end of the auxiliary power supply circuit of the transformer is connected with the externally applied input voltage, the output end of the auxiliary power supply circuit of the transformer is connected with the power supply end of the switching power supply IC chip, and the auxiliary power supply circuit of the transformer is also connected with the constant current charging turn-off circuit; the input end of the constant current charging turn-off circuit is connected with the auxiliary power supply circuit of the transformer, and the output end of the constant current charging turn-off circuit is connected with the constant current charging circuit. After the power supply is electrified, the constant current charging circuit supplies power to the IC chip, and after the IC chip is started, the transformer auxiliary power supply circuit supplies power to the IC chip and turns off the constant current charging circuit. The starting circuit provided by the invention can realize constant-current charging, and is high in starting speed and low in power consumption.
Description
Technical Field
The invention relates to a starting circuit of a switching power supply, in particular to a constant current starting circuit with an ultra-wide input voltage range, and belongs to the technical field of starting of switching power supplies.
Background
The switching power supply has the advantages of high efficiency, high reliability, small volume and the like, and is widely applied to the fields of communication, electronics, industry and the like. In some special application occasions, the switching power supply is required to work normally in a very wide voltage range, such as a photovoltaic system, a UPS and the like, in addition, in industrial application occasions, the power grid voltage is often changed by the change of an electricity load, especially when the load is large, the situation is particularly serious, in addition, in storage battery power supply occasions, such as a power car system, a BMS battery management system and the like, the input voltage range is very wide. Aiming at the application working conditions, considering the alternating current mains supply covering the full voltage range and meeting the requirement of most storage battery power supply occasions, an input voltage range is often required to be designed as follows: the design of the starting circuit is a key and difficult point for a switch power supply with an input voltage range of 88-264VAC and an ultra-wide range of 18-400 VDC.
An existing starting circuit is shown in fig. 1, a series of very large resistors (R1 to Rn) are connected in series on a power supply, and a starting current Istar of a switching power supply is obtained through Vin/R, wherein Vin is an input voltage, R is the sum of the resistor series R1 to Rn, and the scheme is not suitable for being used as a starting circuit of a power supply with an ultra-wide input voltage range.
In view of this, it is necessary to design a new constant current start-up circuit with ultra-wide input voltage range to solve the above technical problems.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: the constant current starting circuit with the ultra-wide input voltage range solves the problems that when the existing starting circuit is applied in the ultra-wide input range, resistance heating is serious during high-voltage input, starting current is small during low-voltage input, starting time is long, and both the starting current and the starting time are difficult to consider.
The invention adopts the following technical scheme for solving the technical problems:
The constant current starting circuit with the ultra-wide input voltage range comprises a constant current charging circuit, a constant current charging turn-off circuit and a transformer auxiliary power supply circuit; the first input end of the constant current charging circuit is connected with a first external input voltage, and the output end of the constant current charging circuit is connected with the power supply end of the switching power supply IC chip; the input end of the transformer auxiliary power supply circuit is connected with a second external input voltage, the output end of the transformer auxiliary power supply circuit is connected with the power supply end of the switching power supply IC chip, and the output end of the transformer auxiliary power supply circuit is also connected with the input end of the constant current charging turn-off circuit; the output end of the constant current charging turn-off circuit is connected with the second input end of the constant current charging circuit;
the constant current charging circuit is used for generating a constant starting current;
the constant current charging turn-off circuit is used for turning off the constant current charging circuit after the switching power supply is started;
The auxiliary power supply circuit of the transformer is used for supplying power to the switching power supply IC chip after the switching power supply is started, and outputting a voltage signal to the constant-current charging turn-off circuit, and the constant-current charging turn-off circuit turns off the constant-current charging circuit by using the voltage signal.
As a preferred embodiment of the present invention, the constant current charging circuit includes: the drain electrode of the first N-type depletion type power field effect transistor is connected with a first external input voltage, the source electrode of the first N-type depletion type power field effect transistor is connected with one end of the first resistor, the other end of the first resistor is connected with the anode of the first diode, the grid electrode of the first N-type depletion type power field effect transistor is connected with one end of the second resistor, the other end of the second resistor is connected with the anode of the first diode, the cathode of the first diode is connected with one end of the first capacitor, the other end of the first capacitor is grounded, the cathode of the first voltage stabilizing diode is connected with the cathode of the first diode, and the anode of the first voltage stabilizing diode is grounded.
As a preferred embodiment of the present invention, the constant current charge turn-off circuit includes: the second N-type enhancement mode field effect transistor, the third resistor, the fourth resistor, the second electric capacity and the third diode, the drain electrode of second N-type enhancement mode field effect transistor links to each other with the grid of first N-type depletion mode power field effect transistor, the source electrode ground of second N-type enhancement mode field effect transistor, the grid of second N-type enhancement mode field effect transistor connects the one end of third resistor, the other end of third resistor links to each other with the negative pole of third diode, the one end of fourth resistor links to each other with the negative pole of third diode, the other end ground of fourth resistor, the both ends parallel connection of second electric capacity and fourth resistor.
As a preferred embodiment of the present invention, the auxiliary power supply circuit for a transformer includes: the input end of the transformer is connected with second external input voltage, one end of the output end of the transformer is connected with one end of the fifth resistor, the other end of the output end of the transformer is grounded, the other end of the fifth resistor is connected with the anode of the second diode, the anode of the second diode is also connected with the anode of the third diode in the constant current charging turn-off circuit, the cathode of the second diode is connected with the anode of the power supply end of the switching power supply IC chip, and the cathode of the second diode is also connected with the cathode of the first diode in the constant current charging circuit.
Compared with the prior art, the technical scheme provided by the invention has the following technical effects:
1. The constant current starting circuit with the ultra-wide input voltage range has a simple structure, is easy to realize, utilizes the drain-source equivalent resistor of the depletion type field effect transistor as a charging current-limiting resistor, automatically adjusts the equivalent resistor according to the input voltage, and can omit a plurality of current-limiting resistors (R1 to Rn) connected in series compared with the prior scheme.
2. Compared with the existing scheme, the invention solves the problems of serious heating of the starting resistor during high-voltage input, small starting current during low-voltage input, long starting time and difficult combination of the starting resistor and the starting resistor.
3. After the switching power supply is started, the constant-current charging turn-off circuit can turn off the constant-current charging circuit, so that the power consumption of the starting loop in the running process of the switching power supply is further reduced.
Drawings
Fig. 1 is a circuit schematic diagram of a conventional starting circuit.
Fig. 2 is a circuit schematic diagram of a constant current start-up circuit with ultra-wide input voltage range according to the present invention.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only for explaining the present invention and are not to be construed as limiting the present invention.
As shown in fig. 1, the present invention discloses a constant current starting circuit with ultra-wide input voltage range, which comprises: 1. a constant current charging circuit; 2. a constant current charging turn-off circuit for turning off the constant current charging circuit; 3. and the transformer assists the power supply circuit. The constant current charging circuit generates a constant starting current. And the constant current charging turn-off circuit is used for turning off the constant current charging circuit after the switching power supply is started. And the transformer auxiliary power supply circuit is used for supplying power to the switching power supply chip after starting, outputting a voltage signal to the constant-current charging turn-off circuit, and the constant-current charging turn-off circuit turns off the constant-current charging circuit by using the voltage signal.
The input end of the constant current charging circuit is connected with the externally applied input voltage, and the output end of the constant current charging circuit is connected with the power supply end of the switching power supply IC chip; the input end of the auxiliary power supply circuit of the transformer is connected with the externally applied input voltage, the output end of the auxiliary power supply circuit of the transformer is connected with the power supply end of the switching power supply IC chip, and the auxiliary power supply circuit of the transformer is also connected with the constant current charging turn-off circuit; the input of the constant current charging turn-off circuit is connected with the auxiliary power supply circuit of the transformer, and the output end of the constant current charging turn-off circuit is connected with the constant current charging circuit.
The constant current charging circuit, as shown in the virtual frame 1 of fig. 2, is composed of a first N-type depletion power field effect transistor Q1, a first resistor R1, a second resistor R2, a first diode D1, a first capacitor C1, and a first zener diode ZD 1. For convenience of description, the gate-source turn-off voltage threshold of Q1 is Vgsth, since Q1 is an N-type depletion power fet, the turn-off voltage threshold is negative, as shown in fig. 2, the voltages between the gate and the source of Q1 are the voltages at the two ends of R1 and R2, during the starting process, since the fet Q2 is not turned on, no current flows through the R2, the voltage between the gate and the source of Q1 is equal to the voltage at the two ends of R1, so that the starting current Istar = Vgsth/R1 generated by the constant current charging circuit during the starting process charges the capacitor C1 through the diode D1, and the zener diode ZD1 is used for overvoltage limiting protection. It can be seen from the expression Istar that the generated start-up current Istar is independent of the input voltage and is determined only by the fet Q1 and the resistor R1, so that the same Istar can be used for charging C1 even under the condition of lower input voltage, thereby greatly reducing the charging time during low-voltage input.
The constant current charging turn-off circuit, as shown in the virtual frame 2 of fig. 2, is composed of a second N-type enhancement type field effect transistor Q2, a third resistor R3, a fourth resistor R4, a second capacitor C2, and a third diode D3. And after the switching power supply finishes starting, the constant-current charging and switching-off circuit controls the Q1 in the constant-current charging circuit to be switched on, and turns off or reduces the charging current Istar, so that the power consumption of the starting circuit in the operation process of the switching power supply is reduced. As shown in fig. 2, after the voltage of C1 is charged to the starting threshold value of the power control chip, the switching power control chip starts to operate, the corresponding auxiliary transformer power supply circuit also starts to operate, the auxiliary transformer power supply circuit supplies power to C2 through D3, the field effect transistor Q2 is turned on, one end of the resistor R2 is grounded through Q2 after Q2 is turned on, the voltages at two ends of the diode D1 are reversely biased, the diode D1 is turned off, istar does not supply power to the switching power IC chip any more, the starting current Istar flows to the ground through R1, R2 and Q2, and Istar at this time is reduced to Vgsth/(r1+r2), and because the value of R2 is very large, the current Istar is close to 0A at this time.
The auxiliary power supply circuit of the transformer, as shown in a virtual box 3 of fig. 2, is composed of a transformer T1B, a fifth resistor R5 and a second diode D2. The transformer auxiliary power supply circuit is used for supplying power to the power supply chip after the switch power supply is started, and controlling the constant current charging turn-off circuit to turn off the constant current charging circuit. As shown in fig. 2, after the voltage of C1 is charged to the starting threshold value of the power control chip, the power chip starts to work, the transformer T1B starts to supply power, the diode D2 is turned on, the transformer auxiliary power supply circuit starts to supply power to the chip, meanwhile, the diode D3 is also turned on, a stable voltage of about ten V is obtained at two ends of C2 after the voltage is filtered by D2 and C2, the voltage at two ends of the capacitor C2 is used for driving the field effect transistor Q2 to be turned on, after Q2 is turned on, the diode D1 is turned off reversely, the constant current charging circuit stops supplying power to the chip, and because the resistance value of R2 is very large, the constant current charging circuit is turned off, istar is reduced to a very low value, and the power consumption of the starting circuit provided by the invention can be basically ignored in the normal operation process after the power is started.
The starting circuit provided by the invention is simple in circuit and easy to realize, is particularly suitable for occasions requiring ultra-wide input voltage range, and can solve the problems that the starting resistor is serious in heating during high-voltage input and is small in starting current and long in starting time during low-voltage input, and the starting circuit are difficult to take account of each other.
The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereto, and any modification made on the basis of the technical scheme according to the technical idea of the present invention falls within the protection scope of the present invention.
Claims (1)
1. The constant current starting circuit with the ultra-wide input voltage range is characterized by comprising a constant current charging circuit, a constant current charging turn-off circuit and a transformer auxiliary power supply circuit; the first input end of the constant current charging circuit is connected with a first external input voltage, and the output end of the constant current charging circuit is connected with the power supply end of the switching power supply IC chip; the input end of the transformer auxiliary power supply circuit is connected with a second external input voltage, the output end of the transformer auxiliary power supply circuit is connected with the power supply end of the switching power supply IC chip, and the output end of the transformer auxiliary power supply circuit is also connected with the input end of the constant current charging turn-off circuit; the output end of the constant current charging turn-off circuit is connected with the second input end of the constant current charging circuit;
the constant current charging circuit is used for generating a constant starting current;
the constant current charging turn-off circuit is used for turning off the constant current charging circuit after the switching power supply is started;
The auxiliary power supply circuit of the transformer is used for supplying power to the switching power supply IC chip after the switching power supply is started, outputting a voltage signal to the constant-current charging turn-off circuit, and the constant-current charging turn-off circuit turns off the constant-current charging circuit by using the voltage signal;
The constant current charging circuit includes: the diode comprises a first N-type depletion type power field effect transistor (Q1), a first resistor (R1), a second resistor (R2), a first diode (D1), a first capacitor (C1) and a first voltage stabilizing diode (ZD 1), wherein the drain electrode of the first N-type depletion type power field effect transistor (Q1) is connected with a first external input voltage, the source electrode of the first N-type depletion type power field effect transistor (Q1) is connected with one end of the first resistor (R1), the other end of the first resistor (R1) is connected with the anode of the first diode (D1), the grid electrode of the first N-type depletion type power field effect transistor (Q1) is connected with one end of the second resistor (R2), the other end of the second resistor (R2) is connected with the anode of the first diode (D1), the other end of the first capacitor (C1) is grounded, and the cathode of the first diode (ZD 1) is connected with the cathode of the first diode (D1);
the constant current charge shutoff circuit includes: the second N-type enhancement mode field effect transistor (Q2), the third resistor (R3), the fourth resistor (R4), the second capacitor (C2) and the third diode (D3), the drain electrode of the second N-type enhancement mode field effect transistor (Q2) is connected with the grid electrode of the first N-type depletion mode power field effect transistor (Q1), the source electrode of the second N-type enhancement mode field effect transistor (Q2) is grounded, the grid electrode of the second N-type enhancement mode field effect transistor (Q2) is connected with one end of the third resistor (R3), the other end of the third resistor (R3) is connected with the cathode of the third diode (D3), one end of the fourth resistor (R4) is connected with the cathode of the third diode (D3), the other end of the fourth resistor (R4) is grounded, and the second capacitor (C2) is connected with two ends of the fourth resistor (R4) in parallel;
The auxiliary power supply circuit of the transformer comprises: the constant-current charging circuit comprises a transformer (T1B), a fifth resistor (R5) and a second diode (D2), wherein the input end of the transformer (T1B) is connected with a second external input voltage, one end of the output end of the transformer (T1B) is connected with one end of the fifth resistor (R5), the other end of the output end of the transformer (T1B) is grounded, the other end of the fifth resistor (R5) is connected with the anode of the second diode (D2), the anode of the second diode (D2) is connected with the anode of a third diode (D3) in the constant-current charging turn-off circuit, the cathode of the second diode (D2) is connected with the positive electrode of the power supply end of the switching power supply IC chip, and the cathode of the second diode (D2) is connected with the cathode of the first diode (D1) in the constant-current charging circuit.
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Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN202364112U (en) * | 2011-11-20 | 2012-08-01 | 合肥华耀电子工业有限公司 | Starting circuit of control chip of switching-mode power supply |
CN104753328A (en) * | 2013-12-30 | 2015-07-01 | 上海五零盛同信息科技有限公司 | Current limiting high voltage start-up circuit of ultra wide input voltage switching power supply |
CN209419484U (en) * | 2018-12-12 | 2019-09-20 | 深圳蓝信电气有限公司 | A kind of Switching Power Supply control chip constant current-supplying circuit and Switching Power Supply |
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2021
- 2021-07-19 CN CN202110813361.8A patent/CN113644816B/en active Active
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN202364112U (en) * | 2011-11-20 | 2012-08-01 | 合肥华耀电子工业有限公司 | Starting circuit of control chip of switching-mode power supply |
CN104753328A (en) * | 2013-12-30 | 2015-07-01 | 上海五零盛同信息科技有限公司 | Current limiting high voltage start-up circuit of ultra wide input voltage switching power supply |
CN209419484U (en) * | 2018-12-12 | 2019-09-20 | 深圳蓝信电气有限公司 | A kind of Switching Power Supply control chip constant current-supplying circuit and Switching Power Supply |
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