CN103166443A - Soft start control circuit and constant flow source drive circuit - Google Patents
Soft start control circuit and constant flow source drive circuit Download PDFInfo
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- CN103166443A CN103166443A CN2011104110399A CN201110411039A CN103166443A CN 103166443 A CN103166443 A CN 103166443A CN 2011104110399 A CN2011104110399 A CN 2011104110399A CN 201110411039 A CN201110411039 A CN 201110411039A CN 103166443 A CN103166443 A CN 103166443A
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Abstract
The invention discloses a soft start control circuit and a constant flow source drive circuit. The soft start control circuit comprises a pulse width control chip U1, a charging resistor R1, a charging capacitor C3 and a triode Q1. The pulse width control chip U1 comprises a pulse modulation signal output pulse-width modulation (PWM) end, a current control RT end and a feedback FB end. The pulse modulation signal output PWM end is used for outputting pulse modulation signals. The charging resistor R1 and the charging capacitor C3 are connected in series between the current control RT end of the pulse width control chip U1 and the ground. A collector electrode of the triode Q1 is connected on the feedback FB end of the pulse width control chip U1. A base electrode of the triode Q1 is connected with a common connecting end between the charging resistor R1 and the charging capacitor C3. An emitting electrode of the triode Q1 is grounded. The soft start control circuit has the advantages of being capable of avoiding the phenomenon of current overshoot generated at the moment a switching power supply is powered on and effectively driving circuit load to work.
Description
Technical field
The present invention relates to the drive circuit field, relate in particular to a kind of SS (soft start) control circuit and a kind of constant current source driving circuit.
Background technology
The drive circuit of drive plate comprises that mostly rectification adds the capacitor filtering circuit.Therefore, close a floodgate moment at power supply, because the initial voltage on filter capacitor is that zero meeting forms very large temporary impact electric current, in power connection moment large impulse current amplitude like this, tending to cause inputting fuse blows, sometimes even with the burning of contact of mains switch, above-mentioned reason all can cause Switching Power Supply normally to devote oneself to work.
Summary of the invention
Technical problem to be solved by this invention is, a kind of SS (soft start) control circuit and a kind of constant current source driving circuit are provided, and can avoid Switching Power Supply in the phenomenon of connecting moment generation current overshoot, and effectively work is carried out in the drive circuit load.
In order to solve the problems of the technologies described above, a kind of SS (soft start) control circuit that embodiments of the invention provide, comprise: pulse width control chip U1, charging resistor R1, charging capacitor C3 and triode Q1, wherein: described pulse width control chip U1 comprises pulse-modulated signal output PWM end, current controling end RT end and feedback end FB end, described pulse-modulated signal output PWM end is the output of this SS (soft start) control circuit, is used for the output pulse-modulated signal; Described charging resistor R1 and described charging capacitor C3 are connected in series between the current controling end RT end and ground of described pulse width control chip U1; The collector electrode of described triode Q1 is connected to the feedback end FB end of described control chip U1, and the base stage of described triode Q1 is connected to the public connecting end of described charging resistor R1 and described charging capacitor C3, the grounded emitter of described triode Q1.
Better, described pulse width control chip U1 be in OB2268 or OB2269 any.
Accordingly, a kind of constant current source driving circuit that the embodiment of the present invention provides comprises input filter capacitor C1, output filter capacitor C2, transformer T1, switching circuit Q, rectification circuit D and SS (soft start) control circuit of the present invention, wherein:
Described input filter capacitor C1 and described switching circuit Q are connected in series between the both positive and negative polarity of DC power supply;
The parallel connection of primary windings of described transformer T1 is at the two ends of described filter capacitor C1, and the secondary coil of described transformer T1 is near described primary coil;
Described rectification circuit D and described output filter capacitor C2 are connected in series in secondary coil two ends;
Described filter capacitor C2 two ends are connected with the load of this drive circuit;
Described SS (soft start) control circuit is connected with described switching circuit Q by its pulse-modulated signal output PWM end, and described pulse-modulated signal output PWM end output pulse-modulated signal is to control described switching circuit Q conducting or to close.
Better, described switching circuit Q is field effect metal-oxide-semiconductor Q2, and the source electrode of described field effect metal-oxide-semiconductor Q2 is connected with input filter capacitor C1, and grid is connected with power cathode, and base stage is connected with the pulse-modulated signal output PWM end of described pulse width control chip U1.
Better, described rectification circuit D be in single rectifier diode, half-wave rectifying circuit, full-wave rectifying circuit and bridge rectifier any.
Better, also be connected with for the discharge diode D1 that input filter capacitor C1 is discharged between the public connecting end of the current controling end RT of described pulse width control chip U1 end and charging resistor R1 and described charging capacitor C3.
Better, the negative pole of described diode D1 is connected to the current controling end RT end of described pulse width control chip U1, and positive pole is connected to the public connecting end of charging resistor R1 and described charging capacitor C3.
Better, described load is the LED lamp string.
The embodiment of the present invention has following advantage or beneficial effect:
The embodiment of the present invention makes the pulse-modulated signal output PWM of the pulse width control chip U1 in this control circuit slowly change the pwm pulse signal output state into by closed condition by the charging resistor R1 in SS (soft start) control circuit, charging capacitor C3 and triode Q1, reaches the purpose of soft start.Can avoid Switching Power Supply in the phenomenon of connecting moment generation current overshoot, effectively drive load and carry out work.
Description of drawings
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, the below will do to introduce simply to the accompanying drawing of required use in embodiment or description of the Prior Art, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain according to these accompanying drawings other accompanying drawing.
Fig. 1 is that the circuit structure of a kind of constant current source driving circuit one embodiment of the present invention forms schematic diagram.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, rather than whole embodiment.Based on the embodiment in the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that obtains under the creative work prerequisite.
Below with reference to accompanying drawing, embodiments of the invention are described.The circuit structure that Figure 1 shows that a kind of constant current source driving circuit one embodiment of the present invention forms schematic diagram.As shown in Figure 1, constant current source driving circuit of the present invention comprises that input filter capacitor C1, output filter capacitor C2, transformer T1, switching circuit Q, rectification circuit D, pulse width control chip U1, charging resistor R1, charging capacitor C3, triode Q1 and discharge diode D1(are optional), wherein: pulse width control chip U1, charging resistor R1, charging capacitor C3, triode Q1 consist of the SS (soft start) control circuit of the embodiment of the present invention.Concrete:
Input filter capacitor C1 and switching circuit Q are connected in series between the both positive and negative polarity of DC power supply, the parallel connection of primary windings of transformer T1 is at the two ends of filter capacitor C1, the secondary coil of transformer T1 is near described primary coil, rectification circuit D and described output filter capacitor C2 are connected in series in the secondary coil two ends of described transformer T1, described filter capacitor C2 two ends are connected with load LED lamp string, and the pulse-modulated signal output PWM end of pulse width control chip U1 is connected with described switching circuit Q; Described charging resistor R1 and described charging capacitor C3 are connected in series between the current controling end RT end and ground of described pulse width control chip U1, the collector electrode of described triode Q1 is connected to the feedback end FB end of described control chip U1, the base stage of described triode Q1 is connected to the public connecting end of described charging resistor R1 and described charging capacitor C3, the grounded emitter of described triode Q1, the negative pole of discharge diode D1 is connected to the current controling end RT end of described pulse width control chip U1, and positive pole is connected to the public connecting end of charging resistor R1 and described charging capacitor C3.
In specific implementation, switching circuit Q in the present invention can be field effect metal-oxide-semiconductor or triode, illustrate as field effect metal-oxide-semiconductor Q2 as example take switching circuit Q in Fig. 1, as shown in Figure 1, when switching circuit Q is field effect metal-oxide-semiconductor Q2, this metal-oxide-semiconductor Q2 is connected with input filter capacitor C1 by its source electrode, is connected with power cathode by its grid, and is connected with the pulse-modulated signal output PWM end of pulse width control chip U1 by its base stage.And when switching circuit Q was triode, this triode can be connected with input aluminum capacitor C1 by its collector electrode, was connected with power cathode by its emitter, and was connected with the pulse-modulated signal output PWM end of pulse width control chip U1 by its base stage.
In specific implementation, the rectification circuit D in the present invention can be in single rectifier diode, half-wave rectifying circuit, full-wave rectifying circuit and bridge rectifier any.Illustrate as diode D2 as example take rectification circuit D in Fig. 1, as shown in Figure 1, when rectification circuit D was diode D2, the positive pole of this diode D2 was connected on the secondary coil of transformer T1, and negative pole is connected to the front end of output filter capacitor C2.Be that half-wave rectifying circuit, full-wave rectifying circuit and bridge rectifier are the common technology means and work as rectification circuit D, the annexation of these circuit and transformer T1 and filter capacitor C2 is known technology, does not give unnecessary details at this.
In specific implementation, described pulse width control chip U1 of the present invention can be in OB2268 or OB2269 any.Illustrate as OB2269 as example take pulse width control chip U1 in Fig. 1.
Operation principle below in conjunction with the circuit of the embodiment of the present invention further describes circuit structure.
As shown in Figure 1, after energising between power positive cathode, at first charged to input filter capacitor C1 by charging resistor R1, at this moment, the primary power at input filter capacitor C1 two ends approximates 0 volt, triode Q1 is in the saturation conduction state, the feedback end FB of pulse width control chip U1 holds conducting over the ground, the voltage (being designated as Vfb) of feedback end FB end approximates 0.3 volt, the pulse-modulated signal output PWM of pulse width control chip U1 end will not have pulse-modulated signal output like this, and field effect metal-oxide-semiconductor Q2 is in cut-off state.Along with charging resistor R1 extended the charging interval of input filter capacitor C1, the voltage at input filter capacitor C1 two ends will raise gradually, voltage when input filter capacitor C1 two ends (is designated as: when Vc1) Vc1 is greater than 0.7 volt, triode Q1 transfers cut-off state to gradually by the saturation conduction state, this moment, the voltage Vfb of feedback end FB end rose gradually, until Vfb is during greater than 1.0 volts, the pulse-modulated signal output PWM end beginning of pulse width control chip U1 progressively has pulse-modulated signal output, reaches the purpose of soft start this moment.When Vfb is elevated to greater than 1.8 volts and during less than 4.4 volts interval, the pulse-modulated signal of the pulse-modulated signal output PWM end output of pulse width control chip U1 is the square wave of rule, this moment, metal-oxide-semiconductor Q2 began steady operation, just can storage power on transformer and release energy to load by rectification circuit, the drive circuit output has stable electric current to pass through like this, and is luminous with regard to there being constant electric current to pass through on load LED lamp string.
In specific implementation, the charging resistor R1 in circuit, output filter capacitor C2 and charging capacitor C3 three determine the needed time of soft start jointly.And diode D1 effect in the present invention is to discharge for input filter capacitor C1.When circuit worked, diode D1 was in cut-off state, and when the circuit shutoff quit work, diode D1 provided discharge loop for input filter capacitor C1, and the charge energy on input filter capacitor C1 is bled off rapidly, for circuit starts ready next time.
The embodiment of the present invention has following advantage or beneficial effect: make the pulse-modulated signal output PWM of the pulse width control chip U1 in this control circuit slowly change the pwm pulse signal output state into by closed condition by the charging resistor R1 in SS (soft start) control circuit, charging capacitor C3 and triode Q1, reach the purpose of soft start.Can avoid Switching Power Supply in the phenomenon of connecting moment generation current overshoot, effectively drive load and carry out work.
Above-described execution mode does not consist of the restriction to this technical scheme protection range.Any at above-mentioned execution mode spirit and principle within do modification, be equal to and replace and improvement etc., within all should being included in the protection range of this technical scheme.
Claims (8)
1. SS (soft start) control circuit, it is characterized in that, comprise: pulse width control chip U1, charging resistor R1, charging capacitor C3 and triode Q1, wherein: described pulse width control chip U1 comprises pulse-modulated signal output PWM end, current controling end RT end and feedback end FB end, described pulse-modulated signal output PWM end is the output of this SS (soft start) control circuit, is used for the output pulse-modulated signal; Described charging resistor R1 and described charging capacitor C3 are connected in series between the current controling end RT end and ground of described pulse width control chip U1; The collector electrode of described triode Q1 is connected to the feedback end FB end of described control chip U1, and the base stage of described triode Q1 is connected to the public connecting end of described charging resistor R1 and described charging capacitor C3, the grounded emitter of described triode Q1.
2. SS (soft start) control circuit as claimed in claim 1, is characterized in that, described pulse width control chip U1 be in OB2268 or OB2269 any.
3. a constant current source driving circuit, is characterized in that, comprises input filter capacitor C1, output filter capacitor C2, transformer T1, switching circuit Q, rectification circuit D and SS (soft start) control circuit as claimed in claim 1 or 2, wherein:
Described input filter capacitor C1 and described switching circuit Q are connected in series between the both positive and negative polarity of DC power supply;
The parallel connection of primary windings of described transformer T1 is at the two ends of described filter capacitor C1, and the secondary coil of described transformer T1 is near described primary coil;
Described rectification circuit D and described output filter capacitor C2 are connected in series in secondary coil two ends;
Described filter capacitor C2 two ends are connected with the load of this drive circuit;
Described SS (soft start) control circuit is connected with described switching circuit Q by its pulse-modulated signal output PWM end, and described pulse-modulated signal output PWM end output pulse-modulated signal is to control described switching circuit Q conducting or to close.
4. constant current source driving circuit as claimed in claim 3, it is characterized in that, described switching circuit Q is field effect metal-oxide-semiconductor Q2, the source electrode of described field effect metal-oxide-semiconductor Q2 is connected with input filter capacitor C1, grid is connected with power cathode, and base stage is connected with the pulse-modulated signal output PWM end of described pulse width control chip U1.
5. constant current source driving circuit as claimed in claim 3, is characterized in that, described rectification circuit D be in single rectifier diode, half-wave rectifying circuit, full-wave rectifying circuit and bridge rectifier any.
6. constant current source driving circuit as described in any one in claim 3-5, it is characterized in that, also be connected with for the discharge diode D1 that input filter capacitor C1 is discharged between the public connecting end of the current controling end RT of described pulse width control chip U1 end and charging resistor R1 and described charging capacitor C3.
7. constant current source driving circuit as claimed in claim 6, is characterized in that, the negative pole of described diode D1 is connected to the current controling end RT end of described pulse width control chip U1, and positive pole is connected to the public connecting end of charging resistor R1 and described charging capacitor C3.
8. constant current source driving circuit as claimed in claim 3, is characterized in that, described load is the LED lamp string.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011104110399A CN103166443A (en) | 2011-12-12 | 2011-12-12 | Soft start control circuit and constant flow source drive circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011104110399A CN103166443A (en) | 2011-12-12 | 2011-12-12 | Soft start control circuit and constant flow source drive circuit |
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| CN103166443A true CN103166443A (en) | 2013-06-19 |
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| CN2011104110399A Pending CN103166443A (en) | 2011-12-12 | 2011-12-12 | Soft start control circuit and constant flow source drive circuit |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104104226A (en) * | 2014-07-20 | 2014-10-15 | 苏州塔可盛电子科技有限公司 | Low-loss switching power supply device applied to PMW controller OB2269 |
| CN104135146A (en) * | 2014-07-29 | 2014-11-05 | 广州金升阳科技有限公司 | Soft starting method and circuit |
| CN104466667A (en) * | 2014-12-03 | 2015-03-25 | 张石 | Low-power-consumption, large-current and high-frequency LD pulse drive circuit |
| CN109742935A (en) * | 2018-11-27 | 2019-05-10 | 中国船舶重工集团公司第七一八研究所 | A kind of high-tension circuit of negative high voltage air-conditioning ion wind apparatus |
| CN110871816A (en) * | 2018-08-29 | 2020-03-10 | 中车大同电力机车有限公司 | Electric locomotive filtering system |
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| CN101277058A (en) * | 2008-02-28 | 2008-10-01 | 艾默生网络能源有限公司 | Secondary time-delay soft start circuit of DC/DC convertor |
| CN201131071Y (en) * | 2007-12-20 | 2008-10-08 | 纵领电子(上海)有限公司 | Constant-current drive circuit of LED |
| CN101355293A (en) * | 2007-07-24 | 2009-01-28 | 青岛海信电器股份有限公司 | Soft startup circuit for power supply |
| CN201550019U (en) * | 2009-11-09 | 2010-08-11 | 扬州双鸿电子有限公司 | Switching power supply with turn-on overshoot preventing circuit |
| CN201805600U (en) * | 2010-09-30 | 2011-04-20 | 杭州电子科技大学 | Primary-side constant-current control device of LED driver |
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| JP2000188193A (en) * | 1998-12-22 | 2000-07-04 | Toshiba Tec Corp | Discharge lamp lighting device |
| CN101355293A (en) * | 2007-07-24 | 2009-01-28 | 青岛海信电器股份有限公司 | Soft startup circuit for power supply |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104104226A (en) * | 2014-07-20 | 2014-10-15 | 苏州塔可盛电子科技有限公司 | Low-loss switching power supply device applied to PMW controller OB2269 |
| CN104135146A (en) * | 2014-07-29 | 2014-11-05 | 广州金升阳科技有限公司 | Soft starting method and circuit |
| WO2016015566A1 (en) * | 2014-07-29 | 2016-02-04 | 广州金升阳科技有限公司 | Soft start method and circuit |
| CN104135146B (en) * | 2014-07-29 | 2017-02-15 | 广州金升阳科技有限公司 | Soft starting method and circuit |
| CN104466667A (en) * | 2014-12-03 | 2015-03-25 | 张石 | Low-power-consumption, large-current and high-frequency LD pulse drive circuit |
| CN110871816A (en) * | 2018-08-29 | 2020-03-10 | 中车大同电力机车有限公司 | Electric locomotive filtering system |
| CN109742935A (en) * | 2018-11-27 | 2019-05-10 | 中国船舶重工集团公司第七一八研究所 | A kind of high-tension circuit of negative high voltage air-conditioning ion wind apparatus |
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