CN207573234U - A kind of Switching Power Supply output soft start circuit - Google Patents
A kind of Switching Power Supply output soft start circuit Download PDFInfo
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- CN207573234U CN207573234U CN201721435587.4U CN201721435587U CN207573234U CN 207573234 U CN207573234 U CN 207573234U CN 201721435587 U CN201721435587 U CN 201721435587U CN 207573234 U CN207573234 U CN 207573234U
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- power supply
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Abstract
The utility model discloses a kind of Switching Power Supply output soft start circuits, it is to realize the output soft start circuit that switch power source output voltage is slowly established, directly and feedback link, real time monitoring, after power supply booting, during rising on the output voltage, by charging to soft start capacitor, and the signal in the charging process is introduced into voltage feedback loop in real time, the duty ratio of pwm chip is limited with the formal expansion of capacitor charging index, output voltage is made also to rise to specified value in the form of capacitor charging index.Relative to the prior art, the utility model output soft-start method, in the case where feedback control loop is by other any power supply modes such as accessory power supply, can still work normally, and the circuit is very simple, only by several small surface mount elements it is enough into, cost is lower, and reliability higher.
Description
Technical field
The utility model is related to field of switch power, specifically, being related to a kind of in switch power supply system, realization to switch
The output soft start circuit that electric power output voltage is slowly established.
Background technology
The all included soft start function of the pwm chip of general Switching Power Supply, Switching Power Supply during starting up,
Switching device is avoided to bear larger current stress and damages or the phenomenon that output voltage overshoot damage electrical equipment occurs.
Although all included soft start function of most of pwm chip, a part of pwm chip is when design
Soft start capacitor is just integrated in the inside of chip, soft-start time can not be adjusted by adjusting the size of soft start capacitor,
So as to cannot many times meet product design requirement；And another part pwm chip is although soft start capacitor is external, it can be with
Freely set, but can not select it is very big because there are the abnormal conditions such as overcurrent, short circuit in power supply and restores weight in pwm chip
Qi Shi since the energy of the soft start capacitor of pwm chip does not discharge also, can cause soft-start time to shorten even soft
The problem of starting failure.
Even if the soft start setting that pwm chip carries is very big, and does not fail, since pwm chip is in original
Side, switch power source output voltage secondary side feedback loop respond feedback from beginning setting up practical primary side, even loop again fast also one
Surely delay is had, be bound to overshoot output voltage during this delay the phenomenon that, at this moment voltage feedback loop
End again in saturation, the phenomenon that owe punching will occur again backward.
And in general system power supply, because of the needs of some functions, such as in charge power supply system, shown in Fig. 1,
The feedback control loop of power supply is powered by accessory power supply, and accessory power supply preferentially starts, so as to make existing conventional output soft start circuit
Soft start capacitor the problem of being fully charged, failing in advance, make the phenomenon that owe punching occur again after output voltage overshoot is serious,
Shown in Fig. 2.
Therefore, it is necessary to the prior art is improved.
Utility model content
In view of this, in order to solve the above-mentioned technical problem, the utility model provides a kind of Switching Power Supply output soft start electricity
Road, to solve the problems, such as that soft start fails in existing switch power supply system.
The purpose of this utility model is achieved through the following technical solutions, a kind of Switching Power Supply output soft start circuit,
Including：First capacitance, first resistor, the first diode.
The output cathode of the first capacitance connection Switching Power Supply, one end and the one or two pole of other end connection first resistor
The anode of pipe, the output negative pole of the other end connecting valve power supply of first resistor, the cathode connecting valve power supply of the first diode
The input terminal of voltage feedback network.
The supply voltage feedback network can be the reference foot of TL431 or the input terminal of amplifier.
What the equivalent scheme as above-mentioned technical proposal was achieved through the following technical solutions, including：First capacitance, the first electricity
Resistance, the first N-type triode.
The output cathode of the first capacitance connection Switching Power Supply, one end of other end connection first resistor and the first N-type
The base stage and collector of triode, the output negative pole of the other end connecting valve power supply of first resistor, the hair of the first N-type triode
The input terminal of emitter-base bandgap grading connecting valve supply voltage feedback network.
The supply voltage feedback network can be the reference foot of TL431 or the input terminal of amplifier.
What the equivalent scheme as above-mentioned technical proposal was achieved through the following technical solutions, including：First capacitance, the first electricity
Resistance, second resistance, the first N-type triode.
The output cathode of the first capacitance connection Switching Power Supply, one end of other end connection first resistor and the first N-type
The base stage of triode, the output negative pole of the other end connecting valve power supply of first resistor, the collector connection of the first N-type triode
One end of second resistance, the output cathode of the other end connecting valve power supply of second resistance, the emitter of the first N-type triode connect
Connect the input terminal of supply voltage switch feedback network.
The second resistance can be 0 Ohmic resistance.
The supply voltage feedback network can be the reference foot of TL431 or the input terminal of amplifier.
What the equivalent scheme as above-mentioned technical proposal was achieved through the following technical solutions, including：First capacitance, the first electricity
Resistance, second resistance, the first N type switch tube.
The output cathode of the first capacitance connection Switching Power Supply, one end of other end connection first resistor and the first N-type
The grid of switching tube, the output negative pole of the other end connecting valve power supply of first resistor, the drain electrode connection the of the first N type switch tube
One end of two resistance, the output cathode of the other end connecting valve power supply of second resistance, the source electrode connection of the first N type switch tube are opened
The input terminal of powered-down source voltage feedback network.
The second resistance can be 0 Ohmic resistance.
The supply voltage feedback network can be the reference foot of TL431 or the input terminal of amplifier.
Compared with prior art, the utility model has the advantages that：
1) this programme solves existing soft starting circuit Problem of Failure；
2) this programme reliability is high, and accommodation is wider；
3) the utility model circuit is simple, at low cost, easily designed；
Description of the drawings
Fig. 1 is existing output soft start circuit schematic diagram；
Fig. 2 is existing output soft start circuit relative voltage waveforms；
Fig. 3 is the circuit diagram that the utility model embodiment one is applied；
Fig. 4 is one relative voltage waveforms of the utility model embodiment；
Fig. 5 is the circuit diagram that the utility model embodiment two is applied；
Fig. 6 is the circuit diagram that the utility model embodiment three is applied；
Fig. 7 is the circuit diagram that the utility model embodiment four is applied.
Specific embodiment
First embodiment
The utility model first embodiment functional block diagram is shown in Fig. 3 dotted line frames, a kind of Switching Power Supply exports soft start
Circuit, including：First capacitance C1, first resistor R1, the first diode D1.
The output cathode of the first capacitance C1 connecting valve power supplys, other end connection first resistor R1 and the first diode
The anode of D1, the output negative pole of the other end connecting valve power supply of first resistor R1, the cathode connecting valve of the first diode D1
The input terminal of supply voltage feedback network.
After power supply booting, during rising on the output voltage, output voltage is by C1, D1, R3 and R4 circuit to circuit
In soft start capacitor C1 chargings, and the charging signals are introduced into feedback control loop in real time, so as to constantly limitation PWM controls core
The formal expansion of the output duty cycle of piece and the index that charged with soft start capacitor C1, makes output voltage also with capacitor charging index
Form rises to specified value, shown in Fig. 4.
After output voltage rises to specified value, output voltage will continue to open to soft in this Weak current circuit by C1, R1
Dynamic condenser C1 charges, and hereafter D1 ends naturally, does not influence the work of supply voltage feedback control loop.
Power supply shutdown, overcurrent, short circuit or other abnormal conditions, after closing output, soft start capacitor C1 will be put by R1
Electricity, in case realization soft start is established in output again.
Particularly, a kind of Switching Power Supply output soft start circuit in the utility model, soft start capacitor can be according to opening
Powered-down product-derived demand arbitrarily designs.
Further, the soft starting circuit only foundation with output voltage whether it is related, with feedback control loop by accessory power supply
It is unrelated etc. other task power supply modes.
Second embodiment
In first embodiment, the diode D1 shown in Fig. 3 dotted line frames can also be N-type triode, institute in Fig. 5 dotted line frames
Show, including：First capacitance C1, first resistor R1, the first N-type triode Q1.
The output cathode of first capacitance C1 connecting valve power supplys, other end connection first resistor R1 and the first N-type triode
The base stage and collector of Q1, the output negative pole of the other end connecting valve power supply of first resistor R1, the first N-type triode Q1's
The input terminal of emitter connecting valve supply voltage feedback network.
After adjustment the operation principle of circuit as first embodiment, it can be achieved that equivalent efficacy.
3rd embodiment
The utility model 3rd embodiment functional block diagram is shown in Fig. 6 dotted line frames, a kind of Switching Power Supply exports soft start
Circuit, including：First capacitance C1, first resistor R1, second resistance R2, the first N-type triode Q1.
The output cathode of the first capacitance C1 connecting valve power supplys, other end connection first resistor R1 and the first N-type three
The base stage of pole pipe Q1, the output negative pole of the other end connecting valve power supply of first resistor R1, the current collection of the first N-type triode Q1
One end of pole connection second resistance R2, the output cathode of the other end connecting valve power supply of second resistance R2, the first N-type triode
The input terminal of the emitter connecting valve supply voltage feedback network of Q1.
After power supply booting, during rising on the output voltage, be pole, R3 and R4 circuit of the output voltage by C1, Q1
It charges to the soft start capacitor C1 in circuit, provides offset signal to the base stage of Q1, Q1 is allowed to be connected, it is equivalent by the charging signals
Feedback control loop is introduced into real time, is referred to so as to constantly limit the output duty cycle of pwm chip with soft start capacitor C1 chargings
Several formal expansions makes output voltage also rise to specified value in the form of capacitor charging index.
After output voltage rises to specified value, output voltage will continue to open to soft in this Weak current circuit by C1, R1
Dynamic condenser C1 charges, and hereafter Q1 ends naturally, does not influence the work of supply voltage feedback control loop.
Power supply shutdown, overcurrent, short circuit or other abnormal conditions, after closing output, soft start capacitor C1 will be put by R1
Electricity, in case realization soft start is established in output again.
Particularly, a kind of Switching Power Supply output soft start circuit in the utility model, soft start capacitor can be according to opening
Powered-down product-derived demand arbitrarily designs.
Further, the soft starting circuit only foundation with output voltage whether it is related, with feedback control loop by accessory power supply
It is unrelated etc. other task power supply modes.
After adjustment the operation principle of circuit as first embodiment, it can be achieved that equivalent efficacy.
Fourth embodiment
In 3rd embodiment, the N-type triode Q1 shown in Fig. 6 dotted line frames can also be N type switch tube, Fig. 7 dotted line frames
Shown in, including：First capacitance C1, first resistor R1, the first N type switch tube Q2 and second resistance R2.
The output cathode of first capacitance C1 connecting valve power supplys, other end connection first resistor R1 and the first N type switch tube
The grid of Q2, the output negative pole of the other end connecting valve power supply of first resistor R1, the drain electrode connection of the first N type switch tube Q2
One end of second resistance R2, the output cathode of the other end connecting valve power supply of second resistance R2, the source of the first N type switch tube Q2
The input terminal of pole connecting valve supply voltage feedback network.
After adjustment the operation principle of circuit as 3rd embodiment, it can be achieved that equivalent efficacy.
It the above is only the preferred embodiment of the utility model, it is noted that above-mentioned preferred embodiment should not regard
For the limitation to the utility model, for those skilled in the art, in the essence for not departing from the utility model
In god and range, several improvements and modifications can also be made, these improvements and modifications also should be regarded as the protection model of the utility model
It encloses, is no longer repeated here with embodiment, the scope of protection of the utility model should be subject to claim limited range.
Claims (4)
1. a kind of Switching Power Supply output soft start circuit, it is characterised in that：Including the first capacitance, first resistor and the one or two pole
Pipe, the output cathode of the first capacitance connection Switching Power Supply, the other end of first capacitance connect the first resistor
The anode of one end and first diode, the output negative pole of the other end connecting valve power supply of the first resistor, described the
The cathode connecting valve power supply of one diode.
2. a kind of Switching Power Supply output soft start circuit according to claim 1, it is characterised in that：With three pole of the first N-type
Pipe replaces first diode, and the base stage and collector of the first N-type triode connect the another of first capacitance simultaneously
One end, the emitter connecting valve power supply of the first N-type triode.
3. a kind of Switching Power Supply output soft start circuit according to claim 2, it is characterised in that：Further include the second electricity
Resistance, the other end of first capacitance connect one end of the first resistor and the base stage of the first N-type triode, and described the
The collector of one N-type triode connects one end of the second resistance, the other end connecting valve power supply of the second resistance
Output cathode.
4. a kind of Switching Power Supply output soft start circuit according to claim 3, it is characterised in that：It is switched with the first N-type
Pipe replaces the first N-type triode, and the grid of first N type switch tube connects the other end of first capacitance, described
The source electrode of first N type switch tube connects one end of the second resistance, the drain electrode connecting valve electricity of first N type switch tube
Source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721435587.4U CN207573234U (en) | 2017-11-01 | 2017-11-01 | A kind of Switching Power Supply output soft start circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721435587.4U CN207573234U (en) | 2017-11-01 | 2017-11-01 | A kind of Switching Power Supply output soft start circuit |
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| Publication Number | Publication Date |
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| CN207573234U true CN207573234U (en) | 2018-07-03 |
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| CN201721435587.4U Active CN207573234U (en) | 2017-11-01 | 2017-11-01 | A kind of Switching Power Supply output soft start circuit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107733219A (en) * | 2017-11-01 | 2018-02-23 | 广州金升阳科技有限公司 | A kind of Switching Power Supply output soft start circuit |
| CN116742951A (en) * | 2022-09-05 | 2023-09-12 | 荣耀终端有限公司 | Switching power supply circuit and electronic device |
-
2017
- 2017-11-01 CN CN201721435587.4U patent/CN207573234U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107733219A (en) * | 2017-11-01 | 2018-02-23 | 广州金升阳科技有限公司 | A kind of Switching Power Supply output soft start circuit |
| CN116742951A (en) * | 2022-09-05 | 2023-09-12 | 荣耀终端有限公司 | Switching power supply circuit and electronic device |
| CN116742951B (en) * | 2022-09-05 | 2024-04-12 | 荣耀终端有限公司 | Switching power supply circuit and electronic device |
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