CN203167383U - Rapid soft starting circuit for inhibiting overshoot - Google Patents
Rapid soft starting circuit for inhibiting overshoot Download PDFInfo
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- CN203167383U CN203167383U CN 201320172045 CN201320172045U CN203167383U CN 203167383 U CN203167383 U CN 203167383U CN 201320172045 CN201320172045 CN 201320172045 CN 201320172045 U CN201320172045 U CN 201320172045U CN 203167383 U CN203167383 U CN 203167383U
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Abstract
The utility model discloses a rapid soft starting circuit for inhibiting overshoot. The circuit comprises an error amplifier, a PWM comparator, an output circuit, a feedback circuit, a current detection circuit, an oscillator and slope compensation circuit, a first current source, a second current source, and a soft starting judging circuit. When input end voltage is less than threshold voltage, an amplifier control end outputs an amplifier shut-off signal to shut down the error amplifier, a first power supply control end outputs a first power supply starting signal such that the first current source works to charge a compensation capacitor circuit, and a second power supply control end outputs a second power shutdown signal to stop the working of the second current source. When the input end voltage reaches the threshold voltage, the amplifier control end outputs an amplifier starting signal to start the error amplifier, the first power supply control end outputs a first power supply shutdown signal to stop the working of the first current source, and the second power supply control end outputs a second current source starting signal to enable the second current source to work.
Description
Technical field
The utility model relates to a kind of being applied in the series LED drive circuit, the quick soft starting circuit of the inhibition output voltage overshoot during boost conversion.
Background technology
In the series LED drive circuit, in order to prevent the excessive and output voltage overshoot of immediate current, need to introduce soft starting circuit when power supply electrifying or circuit start, be damaged to prevent chip or exterior electrical components, and avoid the flicker when starting of LED lamp.
Chinese invention patent CN102695343A discloses a kind of soft start control mode, soft starting circuit is selected by the reference voltage of current source to electric capacity charging generation feedback circuit, rising gradually along with this voltage, output voltage and feedback voltage also raise gradually, and the reference voltage with standard after soft start is finished changes the reference voltage of doing feedback circuit.
In this soft starting mode, use two groups of auxiliary soft start voltage signals, the control mode more complicated, and all need current source to give special electric capacity charging, these electric capacity will occupy bigger chip area, expend a lot of resources.In addition, this class soft starting mode need arrange long soft-start time, if overshoot appears in soft-start time setting too short output voltage easily.
Summary of the invention
Because the problems referred to above of prior art the utility model proposes the quick soft starting circuit of a kind of inhibition overshoot, one of its order is to simplify soft starting circuit, saves chip area.
Two of its purpose is, suppresses the output voltage overshoot when shortening soft-start time.
The utility model addresses the above problem by the following technical programs:
The quick soft starting circuit of a kind of inhibition overshoot comprises: the error amplifier of Lian Jieing, PWM comparator, output circuit and feedback circuit successively; Be connected the output of output circuit and the current detection circuit between the input in the same way of PWM comparator; The oscillator and the slope compensation circuit that are connected with the input in the same way of PWM comparator; Wherein: the in-phase input end of described error amplifier connects a canonical reference voltage, and its inverting input connects described feedback circuit, and its output links to each other with inverting input and a building-out capacitor circuit of described PWM comparator; The quick soft starting circuit of described inhibition overshoot also comprises: first current source, and its inverting input with described building-out capacitor circuit and PWM comparator is connected; Second current source, it is connected with the input in the same way of described PWM comparator, and exports the input in the same way of PWM comparator after the output of output, oscillator and the slope compensation circuit of its output and the described current detection circuit stack to; The soft start decision circuitry, its input links to each other with the inverting input of described error amplifier, and its amplifier control end, first power control terminal and second source control end link to each other with the control end of error amplifier, the Enable Pin of first current source and the Enable Pin of second current source respectively; And at input terminal voltage during less than threshold voltage, the amplifier control end is exported an amplifier shutdown signal and is closed error amplifier, first power control terminal is exported one first electric power starting signal makes the described first current source work charge to described building-out capacitor circuit, and the second source control end is exported a second source shutdown signal does not work described second current source; When input terminal voltage reaches threshold voltage, the amplifier control end is exported an amplifier start signal and is opened error amplifier, first power control terminal is exported one first power-off signal does not work described first current source, and the second source control end is exported one second current source start signal and made the described second current source work.
Described building-out capacitor circuit comprises output and first resistance between the ground and first electric capacity that is connected on described error amplifier successively.
Described feedback circuit comprises the output that is serially connected in described output circuit successively and several diodes and the feedback resistance between the ground, and the input of the inverting input of described error amplifier and soft start decision circuitry is connected between described feedback resistance and the adjacent diode thereof.
Described output circuit comprises and is serially connected in the logic control circuit of PWM comparator between feedback circuit and the current converter circuit of being made up of inductance and switch successively, and the hour hands end of described logic control circuit links to each other with described oscillator and slope compensation circuit.
The input in the same way of described PWM comparator also is connected with second resistance of a ground connection.
Soft start-up process of the present utility model has been utilized existing building-out capacitor, need not extra electric capacity, has saved area of chip, has realized the quick soft start of no overshoot phenomenon simultaneously.
Description of drawings
Fig. 1 is circuit theory diagrams of the present utility model;
Fig. 2 is the change in voltage figure of each key point in the existing SS (soft start) control circuit;
Fig. 3 is the change in voltage figure of each key point in the SS (soft start) control circuit of the present utility model.
Embodiment:
Below in conjunction with embodiment, describe the utility model in detail.
Referring to shown in Figure 1, be the quick soft starting circuit of inhibition overshoot of the present utility model, comprising: the error amplifier 1 of Lian Jieing, PWM comparator 2, output circuit 3 and feedback circuit 4 successively; Be connected the output of output circuit 3 and the current detection circuit between the input 5 in the same way of PWM comparator 2; The oscillator and the slope compensation circuit 6 that are connected with the input in the same way of PWM comparator 2; Wherein: the in-phase input end of described error amplifier 1 connects a canonical reference voltage Vref, and its inverting input connects described feedback circuit 4, and its output links to each other with inverting input and a building-out capacitor circuit 7 of described PWM comparator 2; The quick soft starting circuit of described inhibition overshoot also comprises: first current source 8, and its inverting input with described building-out capacitor circuit 7 and PWM comparator 2 is connected; Second current source 9, it is connected with the input in the same way of described PWM comparator 2, and exports the input in the same way of PWM comparator 2 after the output of output, oscillator and the slope compensation circuit 6 of its output and described current detection circuit 5 stack to; Soft start decision circuitry 10, its input links to each other with the inverting input of described error amplifier 1, and its amplifier control end 101, first power control terminal 102 and second source control end 103 link to each other with the control end 11 of error amplifier, the Enable Pin 81 of first current source and the Enable Pin 91 of second current source respectively; And at input terminal voltage during less than threshold voltage, amplifier control end 101 outputs one amplifier shutdown signal is closed error amplifier 1, first power control terminal, 102 outputs, one first electric power starting signal makes 8 work of described first current source to described building-out capacitor circuit charging 7, and second source control end 103 outputs one second source shutdown signal is not worked described second current source 9; When input terminal voltage reaches threshold voltage, amplifier control end 101 outputs one amplifier start signal is opened error amplifier 1, first power control terminal, 102 outputs, one first power-off signal is not worked described first current source 8, and second source control end 103 outputs one second current source start signal makes 9 work of described second current source.
Described building-out capacitor circuit 7 comprises output and first resistance R 1 between the ground and first capacitor C 1 that is connected on described error amplifier successively.
Described feedback circuit 4 comprises output and several diodes between the ground and the feedback resistance Rs that is serially connected in described output circuit 3 successively, and the input of the inverting input of described error amplifier 1 and soft start decision circuitry 10 is connected between described feedback resistance Rs and the adjacent diode thereof.
Described output circuit 3 comprises the logic control circuit 31 that is serially connected in successively between PWM comparator 2 and the feedback circuit 4 and the current converter circuit of being made up of inductance and switch 32, and the hour hands end of described logic control circuit 31 links to each other with described oscillator and slope compensation circuit 6.
The input in the same way of described PWM comparator 2 also is connected with second resistance R 2 of a ground connection.
In Fig. 1, ramp represents the slope output signal, and comp represents the exit point of error amplifier.
Operation principle of the present utility model is: earlier error amplifier 1 is turn-offed when starting, allow system be in open loop situations, the DC component that ramp is ordered is set to Vd-Vos, output at error amplifier 1 is that the comp end adds a little current source to building-out capacitor C1 charging, along with the comp terminal voltage slowly raises, inductive current peak and output voltage also raise gradually, the feedback voltage that output voltage produces through electric resistance partial pressure triggers the soft start decision circuitry and produces soft start end signal sse charging current source is turned off when reaching the voltage threshold Vss_ref of 0.9 times of reference voltage, and error amplifier opened, system enters the loop operating state, meanwhile the DC component with the ramp waveform is lifted to predetermined value Vd, and system is issued to steady-working state in the control of loop then.
Come concrete elaboration principle of the present utility model in conjunction with Fig. 1, get soft start end threshold voltage (being the input voltage of the inverting input of error amplifier) and be 0.9 times of canonical reference voltage, be i.e. Vss_ref=0.9*Vref.Before system starts working, output stage voltage and feedback voltage are zero or far below the value of target voltage, soft start decision circuitry 10 at first detects feedback voltage and finishes threshold value Vss_ref less than soft start, output decision logic signal see turns off error amplifier 1, simultaneously first current source 8 is opened, second current source 9 is kept off state, allows whole system be in the operate in open loop state state.First current source 8 makes the output comp point voltage of error amplifier 1 rise gradually for the lasting charging of building-out capacitor C1, also along with increasing gradually, output point voltage Vout and feedback voltage fb's peak value of inductance will slowly raise under the modulating action of ramp signal ramp.
When feedback voltage fb magnitude of voltage reaches soft start threshold value Vss_ref, trigger soft start decision circuitry 10 and produce soft start end signal sse, first current source 8 is turn-offed, simultaneously error amplifier 1 is opened, the system that makes enters the loop state of a control, outstanding feature of the present utility model is that soft start end signal sse opens second current source 9 and keeps when soft start finishes, below sets forth the purpose of this measure.
If there is not second current source circuit, in order to finish soft start within a short period of time, under the modulating action of ramp signal ramp, make that the comp point voltage reached predetermined voltage when soft start finished, after system entered the loop state of a control, error amplifier was started working.Because feedback voltage fb is also less than canonical reference voltage Vref, the difference that error amplifier can amplify them raises output, be that the comp point voltage further raises on original basis, equate with canonical reference voltage that up to feedback voltage the comp point voltage just begins to descend.This moment, output voltage reached predetermined voltage, and the comp point voltage is higher than predetermined value, and output point has then produced overshoot when getting back to predetermined value under the control of comp point voltage at loop, as shown in Figure 2.
The introducing of second current source is when soft start finishes, direct voltage with the ramp signal when error amplifier is drawn high the comp point voltage is lifted to predetermined value, thereby offset the difference of comp point voltage and ramp signal, the comp point voltage also just is in predetermined value when output voltage reaches predetermined value like this, just overshoot phenomenon can not produced, as shown in Figure 3 yet.
Should be understood that these execution modes only are used for explanation the utility model and are not used in the scope of the present utility model that limits.Should be understood that in addition those skilled in the art can make various changes or modifications the utility model after the content of having read the utility model instruction, these equivalent form of values fall within the application's appended claims institute restricted portion equally.
Claims (5)
1. one kind is suppressed the quick soft starting circuit of overshoot, comprising: the error amplifier of Lian Jieing, PWM comparator, output circuit and feedback circuit successively; Be connected the output of output circuit and the current detection circuit between the input in the same way of PWM comparator; The oscillator and the slope compensation circuit that are connected with the input in the same way of PWM comparator; Wherein:
The in-phase input end of described error amplifier connects a canonical reference voltage, and its inverting input connects described feedback circuit, and its output links to each other with inverting input and a building-out capacitor circuit of described PWM comparator;
It is characterized in that: the quick soft starting circuit of described inhibition overshoot also comprises:
First current source, its inverting input with described building-out capacitor circuit and PWM comparator is connected;
Second current source, it is connected with the input in the same way of described PWM comparator, and exports the input in the same way of PWM comparator after the output of output, oscillator and the slope compensation circuit of its output and the described current detection circuit stack to;
The soft start decision circuitry, its input links to each other with the inverting input of described error amplifier, and its amplifier control end, first power control terminal and second source control end link to each other with the control end of error amplifier, the Enable Pin of first current source and the Enable Pin of second current source respectively; And at input terminal voltage during less than threshold voltage, the amplifier control end is exported an amplifier shutdown signal and is closed error amplifier, first power control terminal is exported one first electric power starting signal makes the described first current source work charge to described building-out capacitor circuit, and the second source control end is exported a second source shutdown signal does not work described second current source; When input terminal voltage reaches threshold voltage, the amplifier control end is exported an amplifier start signal and is opened error amplifier, first power control terminal is exported one first power-off signal does not work described first current source, and the second source control end is exported one second current source start signal and made the described second current source work.
2. the quick soft starting circuit of inhibition overshoot according to claim 1, it is characterized in that: described building-out capacitor circuit comprises output and first resistance between the ground and first electric capacity that is connected on described error amplifier successively.
3. the quick soft starting circuit of inhibition overshoot according to claim 1, it is characterized in that: described feedback circuit comprises the output that is serially connected in described output circuit successively and several diodes and the feedback resistance between the ground, and the input of the inverting input of described error amplifier and soft start decision circuitry is connected between described feedback resistance and the adjacent diode thereof.
4. the quick soft starting circuit of inhibition overshoot according to claim 1, it is characterized in that: described output circuit comprises and is serially connected in the logic control circuit of PWM comparator between feedback circuit and the current converter circuit of being made up of inductance and switch successively, and the hour hands end of described logic control circuit links to each other with described oscillator and slope compensation circuit.
5. the quick soft starting circuit of inhibition overshoot according to claim 1, it is characterized in that: the input in the same way of described PWM comparator also is connected with second resistance of a ground connection.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320172045 CN203167383U (en) | 2013-04-08 | 2013-04-08 | Rapid soft starting circuit for inhibiting overshoot |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320172045 CN203167383U (en) | 2013-04-08 | 2013-04-08 | Rapid soft starting circuit for inhibiting overshoot |
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| CN203167383U true CN203167383U (en) | 2013-08-28 |
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| CN 201320172045 Expired - Lifetime CN203167383U (en) | 2013-04-08 | 2013-04-08 | Rapid soft starting circuit for inhibiting overshoot |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103683889A (en) * | 2013-11-28 | 2014-03-26 | 无锡中星微电子有限公司 | Soft-start circuit applied to DC-DC (direct-current) converter |
| CN106686850A (en) * | 2015-11-10 | 2017-05-17 | 帝奥微电子有限公司 | Light-emitting diode soft start circuit |
| CN107182148A (en) * | 2017-06-30 | 2017-09-19 | 上海灿瑞科技股份有限公司 | A kind of DC DC LED drive circuits dimmed based on PWM |
| CN109076670A (en) * | 2016-05-13 | 2018-12-21 | 锋翔科技有限公司 | The method and system of acceleration starting for switching regulaor |
| CN112235903A (en) * | 2020-10-29 | 2021-01-15 | 深圳市必易微电子股份有限公司 | Control circuit, control method and LED drive circuit thereof |
| CN112803742A (en) * | 2021-02-27 | 2021-05-14 | 华为技术有限公司 | DC/DC converter and soft start overshoot prevention method thereof |
| CN113364272A (en) * | 2021-06-21 | 2021-09-07 | 弘大芯源(深圳)半导体有限公司 | Smooth starting system of direct-current voltage converter |
-
2013
- 2013-04-08 CN CN 201320172045 patent/CN203167383U/en not_active Expired - Lifetime
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103683889A (en) * | 2013-11-28 | 2014-03-26 | 无锡中星微电子有限公司 | Soft-start circuit applied to DC-DC (direct-current) converter |
| CN106686850A (en) * | 2015-11-10 | 2017-05-17 | 帝奥微电子有限公司 | Light-emitting diode soft start circuit |
| CN106686850B (en) * | 2015-11-10 | 2019-06-04 | 帝奥微电子有限公司 | Light emitting diode soft starting circuit |
| CN109076670A (en) * | 2016-05-13 | 2018-12-21 | 锋翔科技有限公司 | The method and system of acceleration starting for switching regulaor |
| CN109076670B (en) * | 2016-05-13 | 2021-09-07 | 锋翔科技有限公司 | Method and system for accelerated start-up of a switching regulator |
| CN107182148A (en) * | 2017-06-30 | 2017-09-19 | 上海灿瑞科技股份有限公司 | A kind of DC DC LED drive circuits dimmed based on PWM |
| CN107182148B (en) * | 2017-06-30 | 2023-09-26 | 上海灿瑞微电子有限公司 | DC-DC LED drive circuit based on PWM dimming |
| CN112235903A (en) * | 2020-10-29 | 2021-01-15 | 深圳市必易微电子股份有限公司 | Control circuit, control method and LED drive circuit thereof |
| CN112235903B (en) * | 2020-10-29 | 2024-05-28 | 深圳市必易微电子股份有限公司 | Control circuit, control method and LED driving circuit thereof |
| CN112803742A (en) * | 2021-02-27 | 2021-05-14 | 华为技术有限公司 | DC/DC converter and soft start overshoot prevention method thereof |
| US11916482B2 (en) | 2021-02-27 | 2024-02-27 | Huawei Technologies Co., Ltd. | DC/DC converter and soft start overshoot prevention method thereof |
| CN113364272A (en) * | 2021-06-21 | 2021-09-07 | 弘大芯源(深圳)半导体有限公司 | Smooth starting system of direct-current voltage converter |
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Legal Events
| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP03 | Change of name, title or address |
Address after: No.16, wei14 Road, Sutong science and Technology Industrial Park, Nantong, Jiangsu Province Patentee after: Jiangsu Dior Microelectronics Co.,Ltd. Address before: 200050, Shanghai, Changning District, West Yan'an Road, No. 726, Hua Min, John Tower, building 21, room K Patentee before: DIOO MICROCIRCUITS Co.,Ltd. |
|
| CP03 | Change of name, title or address | ||
| CP02 | Change in the address of a patent holder |
Address after: 6 / F, building 8, Zilang science and Technology City, Nantong Innovation Zone, 60 Chongzhou Avenue, Nantong City, Jiangsu Province 226000 Patentee after: Jiangsu Dior Microelectronics Co.,Ltd. Address before: No.16, wei14 Road, Sutong science and Technology Industrial Park, Nantong, Jiangsu Province Patentee before: Jiangsu Dior Microelectronics Co.,Ltd. |
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| CP02 | Change in the address of a patent holder | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130828 |
|
| CX01 | Expiry of patent term |