CN113644816A - Constant current starting circuit of super wide input voltage range - Google Patents
Constant current starting circuit of super wide input voltage range Download PDFInfo
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- CN113644816A CN113644816A CN202110813361.8A CN202110813361A CN113644816A CN 113644816 A CN113644816 A CN 113644816A CN 202110813361 A CN202110813361 A CN 202110813361A CN 113644816 A CN113644816 A CN 113644816A
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- 238000010277 constant-current charging Methods 0.000 claims abstract description 71
- 230000005669 field effect Effects 0.000 claims description 15
- 239000003990 capacitor Substances 0.000 claims description 13
- 238000007600 charging Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 230000000087 stabilizing effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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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 an 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 an external input voltage, and the output end of the constant current charging circuit is connected with the power supply end of the switch power supply IC chip; the input end of the transformer auxiliary power supply circuit is connected with an external input voltage, and 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 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 transformer auxiliary power supply circuit, 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 powered on, 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 has the advantages of high starting speed and low 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 size 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 wide voltage range, such as a photovoltaic system, a UPS and the like, in addition, in industrial application occasions, the voltage of a power grid is often changed due to the change of an electric load, particularly the situation is serious when the load is large, and in addition, in storage battery power supply occasions, such as a power vehicle system, a BMS battery management system and the like, the change of an input voltage range is extremely wide. To above application condition, consider the alternating current commercial power that covers full voltage range to satisfy the power supply occasion of most storage batteries, often need design an input voltage range and be: 88-264VAC, and an ultra-wide range switching power supply of 18-400 VDC, aiming at the switching power supply with such a wide input voltage range, the design of a starting circuit is a key point and a difficult point.
A kind of existing starting circuit is shown in fig. 1, a string of very large resistors (R1 to Rn) is connected in series on the power supply, and the starting current Istar of the switching power supply is obtained through Vin/R, where Vin is the input voltage, and R is the sum of the resistor strings R1 to Rn, this kind of scheme is not suitable for the starting circuit of the power supply with ultra-wide input voltage range, and when the input voltage is high, to avoid the resistor power consumption being large and the heating being serious, the R with very large resistance value needs to be used, and when the input voltage is low, because the R resistor is too large, the input voltage Vin is small, the Istar is very small, the starting time of the power supply is very long, even the minimum starting current of the power supply control chip can not be satisfied.
Therefore, it is necessary to design a new constant current starting circuit with an ultra-wide input voltage range to solve the above-mentioned technical problem.
Disclosure of Invention
The technical problem to be solved by the invention is 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, a resistor generates heat seriously when high voltage is input, the starting current is small and the starting time is long when low voltage is input, and the resistance and the starting time are difficult to take into account.
The invention adopts the following technical scheme for solving the technical problems:
a constant current starting circuit with an 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 the 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 transformer auxiliary power supply circuit is used for supplying power to the switch power supply IC chip after the switch 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.
As a preferable aspect of the present invention, the constant current charging circuit includes: the power supply circuit comprises a first N-type depletion type power field effect transistor, a first resistor, a second resistor, a first diode, a first capacitor and a first voltage stabilizing diode, wherein a drain electrode of the first N-type depletion type power field effect transistor is connected with a first external input voltage, a 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 an anode of the first diode, a 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 an anode of the first diode, a cathode of the first diode is connected with one end of the first capacitor, the other end of the first capacitor is grounded, a cathode of the first voltage stabilizing diode is connected with a cathode of the first diode, and an anode of the first voltage stabilizing diode is grounded.
As a preferable aspect of the present invention, the constant current charging shutdown circuit includes: the drain electrode of the second N-type enhancement type field effect transistor is connected with the grid electrode of the first N-type depletion type power field effect transistor, the source electrode of the second N-type enhancement type field effect transistor is grounded, the grid electrode of the second N-type enhancement type field effect transistor is connected with one end of the third resistor, the other end of the third resistor is connected with the cathode of the third diode, one end of the fourth resistor is connected with the cathode of the third diode, the other end of the fourth resistor is grounded, and the two ends of the second capacitor and the two ends of the fourth resistor are connected in parallel.
As a preferable aspect of the present invention, the transformer auxiliary power supply circuit includes: the input end of the transformer is connected with a 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 invention adopting the technical scheme has the following technical effects:
1. the constant current starting circuit with the ultra-wide input voltage range is simple in structure and easy to realize, the drain-source equivalent resistance of the depletion type field effect transistor is used as the charging current limiting resistance, the size of the equivalent resistance is automatically adjusted according to the size of the input voltage, and compared with the existing scheme, a plurality of series-connected current limiting resistances (R1-Rn) can be omitted.
2. Compared with the prior art, the invention solves the problems that the starting resistor generates heat seriously when high voltage is input, the starting current is small and the starting time is long when low voltage is input, and the starting resistor are difficult to be compatible.
3. According to the invention, after the switching power supply is started, the constant current charging circuit can be turned off by the constant current charging turn-off circuit, so that the power consumption of the starting circuit in the operation process of the switching power supply is further reduced.
Drawings
Fig. 1 is a circuit diagram of a conventional start-up circuit.
Fig. 2 is a circuit diagram of a constant current start circuit for a super wide input voltage range according to the present invention.
Detailed Description
Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of 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 start circuit with an ultra-wide input voltage range, wherein the start circuit comprises: 1. a constant current charging circuit; 2. the constant current charging turn-off circuit is used for turning off the constant current charging circuit; 3. 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 the starting is finished, outputting a voltage signal to the constant current charging turn-off circuit, and turning off the constant current charging circuit by the constant current charging turn-off circuit by using the signal.
The input end of the constant current charging circuit is connected with an external input voltage, and the output end of the constant current charging circuit is connected with the power supply end of the switch power supply IC chip; the input end of the transformer auxiliary power supply circuit is connected with an external input voltage, and 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 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 transformer auxiliary power supply circuit, 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 dashed box 1 of fig. 2, is composed of a first N-type depletion power fet 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, let the gate-source turn-off voltage threshold of Q1 be Vgsth, since Q1 is an N-type depletion mode power fet, the turn-off voltage threshold is a negative value, as shown in fig. 2, the voltage between the gate and the source of Q1 is the voltage across R1 and R2, during the starting process, since fet Q2 is not turned on, no current flows through R2, and the voltage between the gate and the source of Q1 is equal to the voltage across R1, the starting current Istar generated by the constant-current charging circuit during the starting process is Vgsth/R1, and the current Istar charges capacitor C1 via diode D1, and zener diode ZD1 is used for overvoltage limiter protection. It can be seen from the expression of Istar that the generated starting current Istar is independent of the input voltage and is determined only by the fet Q1 and the resistor R1, which can ensure that the same Istar can be used to charge the C1 even at a lower input voltage, thereby greatly reducing the charging time at low voltage input.
The constant-current charging shutdown circuit, as shown in the dashed box 2 of fig. 2, is composed of a second N-type enhancement mode fet Q2, a third resistor R3, a fourth resistor R4, a second capacitor C2, and a third diode D3. The constant-current charging turn-off circuit is used for controlling the Q1 in the constant-current charging circuit to be switched on and turn off or reduce the charging current Istar after the switching power supply is started, 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 start threshold of the power control chip, the power control chip starts to operate, the corresponding transformer auxiliary power supply circuit also starts to operate, the transformer auxiliary power supply circuit supplies power to C2 through D3, the field effect transistor Q2 is turned on, after Q2 is turned on, one end of the R2 resistor is grounded through Q2, the voltage at the two ends of the diode D1 is reversely biased, the diode D1 is turned off, Istar no longer supplies power to the IC chip of the switching power supply, the start current Istar flows to the ground through R1, R2, and Q2, and Istar at this time is reduced to Vgsth/(R1+ R2), and since the value of R2 is very large, the current Istar at this time is close to 0A.
The transformer auxiliary power supply circuit, as shown in the dashed 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 switching 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, when the voltage of C1 is charged to the start threshold of the power control chip, the power chip starts to operate, 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, the diode D3 is also turned on, a stable voltage of about ten and several volts is obtained at two ends of C2 after filtering by D2 and C2, the voltage at two ends of the capacitor C2 is used to drive the fet Q2 to be turned on, the diode D1 is turned off in the reverse direction after the Q2 is turned on, the constant current charging circuit stops supplying power to the chip, and since the resistance of R2 is large, the Istar is reduced to a very low value after the constant current charging circuit is turned off, and the power consumption of the start loop proposed by the present invention can be basically ignored during the normal operation after the power control chip is started.
The starting circuit provided by the invention has the advantages of simple circuit and easiness in realization, is particularly suitable for occasions with ultra-wide input voltage range requirements, and can solve the problems that a starting resistor generates heat seriously when high voltage is input, the starting current is small and the starting time is long when low voltage is input, and the two are difficult to take into account in the traditional RC-based charging starting circuit.
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 thereby, and any modifications made on the basis of the technical scheme according to the technical idea of the present invention fall within the protection scope of the present invention.
Claims (4)
1. A constant current starting circuit with an ultra-wide input voltage range is characterized in that the constant current starting circuit 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 the 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 transformer auxiliary power supply circuit is used for supplying power to the switch power supply IC chip after the switch 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.
2. The ultra-wide input voltage range constant current startup circuit of claim 1, wherein the constant current charging circuit comprises: a first N-type depletion power FET (Q1), a first resistor (R1), a second resistor (R2), a first diode (D1), a first capacitor (C1) and a first zener diode (ZD1), wherein the drain of the first N-type depletion power FET (Q1) is connected with a first external input voltage, the source of the first N-type depletion power FET (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 gate of the first N-type depletion power FET (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 cathode of the first diode (D1) is connected with one end of the first capacitor (C6), the other end of the first capacitor (C1) is connected with the cathode of the first zener diode (ZD1), the anode of the first zener diode (ZD1) is connected to ground.
3. The ultra-wide input voltage range constant current startup circuit of claim 2, wherein the constant current charge shutdown circuit comprises: the power source circuit comprises 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), wherein the drain of the second N-type enhancement type field effect transistor (Q2) is connected with the grid of the first N-type depletion type power field effect transistor (Q1), the source of the second N-type enhancement type field effect transistor (Q2) is grounded, the grid of the second N-type enhancement type 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 two ends of the second capacitor (C2) and the fourth resistor (R4) are connected in parallel.
4. The ultra-wide input voltage range constant current startup circuit of claim 3, wherein the transformer auxiliary power supply circuit comprises: the input end of the transformer (T1B), the fifth resistor (R5) and the second diode (D2), the input end of the transformer (T1B) is connected with the 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 also connected with the anode of the third diode (D3) in the constant current charging turn-off circuit, the cathode of the second diode (D2) is connected with the anode of the power supply end of the switching power supply IC chip, and the cathode of the second diode (D2) is also connected with the cathode of the first diode (D1) in the constant current charging circuit.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110813361.8A CN113644816B (en) | 2021-07-19 | 2021-07-19 | Constant current starting circuit with ultra-wide input voltage range |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110813361.8A CN113644816B (en) | 2021-07-19 | 2021-07-19 | Constant current starting circuit with ultra-wide input voltage range |
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| CN113644816A true CN113644816A (en) | 2021-11-12 |
| CN113644816B CN113644816B (en) | 2024-04-26 |
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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 |
-
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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| CN113644816B (en) | 2024-04-26 |
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