CN203590013U - Soft-start circuit applied to DC-DC converter - Google Patents
Soft-start circuit applied to DC-DC converter Download PDFInfo
- Publication number
- CN203590013U CN203590013U CN201320772508.4U CN201320772508U CN203590013U CN 203590013 U CN203590013 U CN 203590013U CN 201320772508 U CN201320772508 U CN 201320772508U CN 203590013 U CN203590013 U CN 203590013U
- Authority
- CN
- China
- Prior art keywords
- voltage
- soft
- output
- transducer
- soft start
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000003990 capacitor Substances 0.000 claims abstract description 12
- 238000006243 chemical reaction Methods 0.000 abstract description 4
- 230000002093 peripheral effect Effects 0.000 abstract description 4
- 238000005070 sampling Methods 0.000 abstract 1
- 230000000630 rising effect Effects 0.000 description 4
- 238000004088 simulation Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000003321 amplification Effects 0.000 description 2
- 230000002045 lasting effect Effects 0.000 description 2
- 238000003199 nucleic acid amplification method Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 1
Images
Landscapes
- Amplifiers (AREA)
- Dc-Dc Converters (AREA)
Abstract
The utility model provides a soft-start circuit applied to a DC-DC converter. The soft-start circuit comprises a conversion unit used for converting input voltage at an input end to output voltage at an output end based on a signal of a control end, a sampling circuit used for acquiring output voltage at an output end of the conversion unit to obtain feedback voltage, a soft-start switch, and an error amplifier having a first input end connected with reference voltage, a second input end for receiving the feedback voltage and an output end connected with a control end of the conversion unit through the soft-start switch. During initial startup, the soft-start switch is controlled for continuous breakover and cut-off; and when startup is completed, the soft-start switch is controlled for continuous breakover. Thus, the soft-start function can be realized, and large external capacitors also can be saved. Modules all can be integrated in a same chip. Chip pins and peripheral devices are reduced. Application cost is low. And competitiveness in practical application is raised.
Description
[technical field]
The utility model relates to circuit design field, particularly a kind of soft starting circuit that is applied to DC-DC transducer.
[background technology]
Fig. 1 shows a kind of DC-DC(direct current-direct current with soft start function, DC-to-DC) a kind of example of transducer.As shown in Figure 1, described DC-DC transducer comprises converting unit 110, error amplifier EA, compensating circuit 120, sample circuit 130, output capacitance COUT.
Described converting unit 110 is converted to the input voltage VIN of input according to the signal of control end the output voltage VO UT of output, and output capacitance COUT is connected between the output and ground of described converting unit 110.Described sample circuit 130 comprises output and the first divider resistance R1 between ground and the second branch pressure voltage R2 that is series at successively described converting unit 110, and the voltage of the intermediate node of two divider resistances is feedback voltage FB.The negative input end of error amplifier EA receives described feedback voltage FB, and its output is connected with the control end of described converting unit 110.Described compensating circuit 120 comprises and is series at successively the control end of described converting unit and the compensating resistance Re between ground and building-out capacitor Ce.Common described converting unit comprises PWM(pulse-width modulation) comparator, triangular-wave generator, logic controller and output circuit, described output circuit can include inductance, power switch and diode.
For the DC-DC transducer without soft start function, the positive input terminal of described error amplifier EA can directly connect a reference voltage.Yet, due to DC-DC transducer startup stage, described error amplifier EA is in nonequilibrium condition, making the pwm control signal of PWM comparator output is 100% duty ratio, therefore having very large surge current pours into output capacitance COUT, make output voltage VO UT produce larger overshoot, surge current is likely loss switching tube and other devices also.The DC-DC transducer with soft start function shown in Fig. 1 arises at the historic moment for this reason.
DC-DC transducer in Fig. 1 also comprises soft starting circuit, and described soft starting circuit comprises current source Iss, capacitor C ss, K switch 1 and K2, reference voltage VREF.
During DC-DC transducer electrifying startup, K switch 1 closure, K switch 2 disconnects, and charges to large capacitor C ss, the soft start voltage Vss that obtains rising on slope by a little current source Iss.With this soft start voltage Vss, replace reference voltage VREF, like this, the positive input terminal voltage rising of error amplifier EA, and then the error of its output amplify voltage EAO also by rising (in initial start up phase, FB is 0V), the duty ratio of the pwm control signal of PWM comparator output increases gradually, thereby reaches the object of soft start.After soft start finishes, K switch 1 disconnects, K switch 2 closures, and reference voltage VREF accesses the positive input terminal of described error amplifier, and assurance DC-DC transducer is normally worked.
The advantage of this method is to be simple and easy to use, shortcoming is to need a soft start capacitor Css to control soft-start time, this electric capacity is often very large, can not be integrated on same chip together with error amplifier EA, converting unit 110, compensating circuit 120, Acquisition Circuit 130, this will increase chip pin and peripheral components, application cost is larger, in practical application, lacks competitiveness.
Therefore, be necessary to propose a kind of improved soft starting circuit, its application cost is lower, and competitiveness is strong.
[utility model content]
The purpose of this utility model is to provide a kind of soft starting circuit of the DC-DC of being applied to transducer, and it can realize with lower application cost the soft start of DC-DC transducer.
In order to address the above problem, according to an aspect of the present utility model, the utility model provides a kind of soft starting circuit of the DC-DC of being applied to transducer, and it comprises: converting unit, and its signal based on control end is converted to the input voltage of input the output voltage of output; Sample circuit, its output voltage that gathers the output of described converting unit obtains feedback voltage; Soft start switch; Error amplifier, its first input end connects reference voltage, and the second input receives described feedback voltage, and its output is connected with the control end of described converting unit through described soft start switch; Be connected in the control end of described converting unit and the compensating circuit between ground, when described DC-DC transducer initial start, control the constantly conducting of described soft start switch and cut-off, when described DC-DC transducer has started, control described soft start switch and continue conducting.
Further, by detecting the voltage of first input end of error amplifier and the voltage of the second input, determine the whether initial start of described DC-DC transducer.Concrete, when the Voltage Establishment of first input end of error amplifier and the voltage of the second input are zero, think the initial start of described DC-DC transducer, control subsequently the constantly conducting of described soft start switch and cut-off.
Further, by detecting the voltage of the second input of error amplifier, whether be increased to and equal first input end voltage and determine whether described DC-DC transducer has started.Concrete, when the voltage of the second input of error amplifier equals first input end voltage, think that described DC-DC transducer has started, control subsequently the lasting conducting of described soft start switch.
Further, when described DC-DC transducer initial start, produce the soft start clock signal of a fixed frequency and duty ratio, and be connected to the control end of described soft start switch, and when described soft start clock signal is the first level, described soft start switch conducting, when described soft start clock signal is second electrical level, described soft start switch cut-off, after described DC-DC transducer has started, produces the soft start clock signal that is continuously second electrical level.
Further, described compensating circuit comprises control end and the compensating resistance between ground and the building-out capacitor that is series at successively described converting unit.
Further, described soft starting circuit also includes and is connected in the output of described converting unit and the output capacitance between ground, described sample circuit comprises output and the first divider resistance between ground and the second divider resistance that is series at successively described converting unit, the voltage of the intermediate node of two divider resistances is feedback voltage, described converting unit comprises PWM comparator, triangular-wave generator, logic controller and output circuit, and described output circuit includes inductance, power transistor and diode.
Further, described error amplifier, compensating circuit, converting unit, sample circuit are integrated in same wafer.
Compared with prior art, DC-DC transducer in the utility model is by arranging soft start switch between the output at error amplifier and the control end of converting unit, when described DC-DC transducer initial start, control the constantly conducting of described soft start switch and cut-off, making error amplify voltage EAO rises gently, when described DC-DC transducer has started, control described full starting switch and continue conducting, so not only can realize soft start function, can also save larger external electric capacity, modules can be integrated in same chip, chip pin and peripheral components have been reduced, application cost is lower, improved competitiveness in practical application.
[accompanying drawing explanation]
In order to be illustrated more clearly in the technical scheme of the utility model embodiment, below the accompanying drawing of required use during embodiment is described is briefly described, apparently, accompanying drawing in the following describes is only embodiment more of the present utility model, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.Wherein:
Fig. 1 is the circuit diagram of the DC-DC transducer with soft start function of the prior art;
Fig. 2 is soft starting circuit in the utility model circuit diagram in one embodiment;
Fig. 3 be soft starting circuit in Fig. 2 startup stage simulation result;
Fig. 4 shown in Fig. 3 startup stage the enlarged drawing of simulation result.
[embodiment]
For above-mentioned purpose of the present utility model, feature and advantage can be become apparent more, below in conjunction with the drawings and specific embodiments, the utility model is described in further detail.
Alleged " embodiment " or " embodiment " refers to special characteristic, structure or the characteristic that can be contained at least one implementation of the utility model herein.Different local in this manual " in one embodiment " that occur not all refer to same embodiment, neither be independent or the embodiment mutually exclusive with other embodiment optionally.Unless stated otherwise, the word that connection herein, the expression that is connected, joins are electrically connected all represents to be directly or indirectly electrical connected.
Fig. 2 is soft start DC-DC transducer 200 (also can be called the soft starting circuit that is applied to DC-DC transducer) in the utility model circuit diagram in one embodiment.As shown in Figure 2, described soft start DC-DC transducer 200 comprises error amplifier 210, soft start switch K, converting unit 220, sample circuit 230, compensating circuit 240, output capacitance COUT.
The signal of described converting unit 220 based on control end C is converted to the input voltage VIN of input the output voltage VO UT of output.In one embodiment, described converting unit 220 comprises PWM comparator, triangular-wave generator, logic controller and output circuit, and described output circuit includes inductance, power switch and diode.An input of PWM comparator is as the control end of described converting unit 220, the triangular signal of another input input triangular-wave generator output, described PWM comparator output pwm signal is given described logic controller, described logic controller is controlled the turn-on and turn-off of the power switch in output circuit based on pwm signal, to complete input voltage to the conversion of output voltage.About converting unit 220 this part content, there are in the prior art a lot of middle implementations, and because this part is not emphasis of the present utility model, therefore in the utility model, have just been not described in detail.
Described sample circuit 230, its output voltage VO UT that gathers the output of described converting unit obtains feedback voltage FB.In one embodiment, described sample circuit 230 comprises output and the first divider resistance R1 between ground and the second divider resistance R2 that is series at successively described converting unit 220, and the voltage of the intermediate node of two divider resistances is feedback voltage FB.
Described output capacitance COUT is connected between the output and ground of described converting unit 220.The first input end of described error amplifier 210 connects a reference voltage VREF, and the second input receives described feedback voltage FB, and its output is connected with the control end C of described converting unit 220 through described soft start switch K.Described compensating circuit 240 is connected between the control end C and ground of described converting unit 220.In one embodiment, described compensating circuit 240 comprises and is series at successively the control end of described converting unit and the compensating resistance Re between ground and building-out capacitor Ce.
In order to realize soft start, when 200 initial start of described DC-DC transducer, the soft start clock signal SS_CLK that generates fixed duty cycle and fixed frequency controls constantly conducting of described soft start switch K and cut-off, the error amplification signal EAO of error amplifier 210 outputs is slowly charged to the building-out capacitor Ce in compensating circuit, like this error amplification signal EAO startup stage rising, thereby realized soft start function.When described DC-DC transducer 200 has started, the soft start clock signal SS_CLK that generation is continuously fixed level controls the lasting conducting of described soft start switch K, to enter follow-up normal operating conditions.Concrete, described soft start clock signal is connected to the control end of described soft start switch K, when described soft start clock signal is the first level, and described soft start switch K conducting, when described soft start clock signal is second electrical level, described soft start switch K cut-off.
DC-DC transducer soft start function in the utility model is actually the building-out capacitor Ce having used in compensating circuit 240, but because the area of building-out capacitor Ce is relatively little, therefore can be integrated in same chip with error amplifier 210, converting unit 220 and sample circuit 230.Compare with the circuit in Fig. 1 like this, just saved the large capacitor C ss in Fig. 1, saved chip pin number and peripheral components, reduced application cost.
In one embodiment, by detecting the voltage of first input end of error amplifier EA and the voltage of the second input, determine the whether initial start of described DC-DC transducer.Concrete, when the voltage of the Voltage Establishment of the first input end of the error amplifier Voltage Establishment of first input end (think after being greater than some voltage thresholds such as the voltage at first input end) and the second input is zero, think the initial start of described DC-DC transducer, control subsequently the continuous conducting of described soft start switch K and cut-off.
In one embodiment, by detecting the voltage (being feedback voltage FB) of the second input of error amplifier EA, determine whether described DC-DC transducer has started, while equaling the voltage of first input end such as the voltage of the second input at error amplifier EA, think that described DC-DC transducer has started, control subsequently described soft start switch and continue conducting.
Fig. 3 be soft start DC-DC transducer in Fig. 2 startup stage simulation result, from 1ms, start initial start, it shows that the transducer start-up course in Fig. 2 is completely normal, can realize soft start function.Because Fig. 3 intermediate-resolution is lower, so SS_CLK is shown as secret note, and the burr on EAO top is also shown as secret note.For clearer, Fig. 4 shown in Fig. 3 startup stage the enlarged drawing of simulation result, it has comparatively clearly shown SS_CLK and EAO signal.
In the utility model in the utility model, " connection ", be connected, word that the expression such as " company ", " connecing " is electrical connected, if no special instructions, represent direct or indirect electric connection.
It is pointed out that being familiar with any change that person skilled in art does embodiment of the present utility model does not all depart from the scope of claims of the present utility model.Correspondingly, the scope of claim of the present utility model is also not limited only to previous embodiment.
Claims (9)
1. a soft starting circuit that is applied to DC-DC transducer, is characterized in that, it comprises:
Converting unit, its signal based on control end is converted to the input voltage of input the output voltage of output;
Sample circuit, its output voltage that gathers the output of described converting unit obtains feedback voltage;
Soft start switch;
Error amplifier, its first input end connects reference voltage, and the second input receives described feedback voltage, and its output is connected with the control end of described converting unit through described soft start switch;
Be connected in the control end of described converting unit and the compensating circuit between ground,
When described DC-DC transducer initial start, control the constantly conducting of described soft start switch and cut-off, when described DC-DC transducer has started, control described soft start switch and continue conducting.
2. soft starting circuit according to claim 1, is characterized in that, by detecting the voltage of first input end of error amplifier and the voltage of the second input, determines the whether initial start of described DC-DC transducer.
3. soft starting circuit according to claim 2, it is characterized in that, when the Voltage Establishment of first input end of error amplifier and the voltage of the second input are zero, think the initial start of described DC-DC transducer, control subsequently the constantly conducting of described soft start switch and cut-off.
4. whether soft starting circuit according to claim 1, is characterized in that, by detecting the voltage of the second input of error amplifier, be increased to and equal first input end voltage and determine whether described DC-DC transducer has started.
5. soft starting circuit according to claim 4, is characterized in that, when the voltage of the second input of error amplifier equals first input end voltage, thinks that described DC-DC transducer has started, and controls subsequently described soft start switch and continues conducting.
6. soft starting circuit according to claim 1, is characterized in that,
When described DC-DC transducer initial start, produce the soft start clock signal of a fixed frequency and duty ratio, and be connected to the control end of described soft start switch, when described soft start clock signal is the first level, described soft start switch conducting, when described soft start clock signal is second electrical level, described soft start switch cut-off, after described DC-DC transducer has started, produce the soft start clock signal that is continuously second electrical level.
7. according to the arbitrary described soft starting circuit of claim 1-6, it is characterized in that, described compensating circuit comprises control end and the compensating resistance between ground and the building-out capacitor that is series at successively described converting unit.
8. soft starting circuit according to claim 7, is characterized in that, it also includes and is connected in the output of described converting unit and the output capacitance between ground,
Described sample circuit comprises output and the first divider resistance between ground and the second divider resistance that is series at successively described converting unit, and the voltage of the intermediate node of two divider resistances is feedback voltage,
Described converting unit comprises PWM comparator, triangular-wave generator, logic controller and output circuit, and described output circuit includes inductance, power transistor and diode.
9. according to the arbitrary described soft starting circuit of claim 1-6, it is characterized in that, described error amplifier, compensating circuit, converting unit, sample circuit are integrated in same wafer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320772508.4U CN203590013U (en) | 2013-11-28 | 2013-11-28 | Soft-start circuit applied to DC-DC converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320772508.4U CN203590013U (en) | 2013-11-28 | 2013-11-28 | Soft-start circuit applied to DC-DC converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203590013U true CN203590013U (en) | 2014-05-07 |
Family
ID=50587860
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320772508.4U Expired - Lifetime CN203590013U (en) | 2013-11-28 | 2013-11-28 | Soft-start circuit applied to DC-DC converter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203590013U (en) |
Cited By (2)
| 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 |
| CN113765353A (en) * | 2020-06-02 | 2021-12-07 | 晶豪科技股份有限公司 | Control circuit for facilitating inrush current reduction for a voltage regulator and voltage regulating device with inrush current reduction |
-
2013
- 2013-11-28 CN CN201320772508.4U patent/CN203590013U/en not_active Expired - Lifetime
Cited By (3)
| 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 |
| CN113765353A (en) * | 2020-06-02 | 2021-12-07 | 晶豪科技股份有限公司 | Control circuit for facilitating inrush current reduction for a voltage regulator and voltage regulating device with inrush current reduction |
| CN113765353B (en) * | 2020-06-02 | 2024-04-12 | 晶豪科技股份有限公司 | Control circuit for facilitating surge current reduction of a voltage regulator and voltage regulating device having the same |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103683889A (en) | Soft-start circuit applied to DC-DC (direct-current) converter | |
| CN102136800B (en) | Switching regulaor | |
| US9425688B2 (en) | Converter circuit and associated method | |
| US9991794B2 (en) | Hybrid capacitive-inductive voltage converter | |
| US8669748B2 (en) | Device for synchronous DC-DC conversion and synchronous DC-DC converter | |
| US9030184B2 (en) | DC-DC converter and voltage conversion method thereof | |
| CN102832806B (en) | Switch voltage stabilizing circuit and voltage feedback method thereof | |
| TWI424667B (en) | Soft-stop device and power convertor using the same | |
| CN103248221B (en) | Step-down controller | |
| US10541599B2 (en) | Soft-start control circuit applied to DC-DC converting system | |
| CN105375798A (en) | Self-adaptive sampling circuit, primary side feedback constant voltage system and switching power supply system | |
| CN108306489A (en) | Drive circuit, control circuit and drive method of buck-boost switching converter | |
| US20220255429A1 (en) | Voltage converter | |
| CN107231096B (en) | Primary side feedback switching power supply multi-order loop control circuit | |
| CN102299615B (en) | Circuit and method for adaptively adjusting fixed conducting time | |
| CN109412397A (en) | A kind of secondary slope compensation circuit of pulse-width-modulated current mode switch power supply | |
| CN113098267B (en) | Switch converter, switch integrated circuit and control circuit thereof | |
| CN103633831A (en) | Control circuit, time calculation unit and control circuit operation method | |
| CN203590013U (en) | Soft-start circuit applied to DC-DC converter | |
| US11171565B2 (en) | Switched-mode power converter | |
| KR101030776B1 (en) | Boost dc/dc converter | |
| CN112653324A (en) | Boost converter system without direct power supply | |
| CN217931786U (en) | Phase compensation sampling circuit | |
| CN102570805A (en) | Buck converter | |
| CN114189132A (en) | Control method and circuit for power factor correction |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CP01 | Change in the name or title of a patent holder |
Address after: 214028 10th Floor, Area A, 530 Building, Qingyuan Road, Taihu International Science Park, Wuxi New District, Jiangsu Province Patentee after: Zgmicro Corporation Address before: 214028 10th Floor, Area A, 530 Building, Qingyuan Road, Taihu International Science Park, Wuxi New District, Jiangsu Province Patentee before: WUXI VIMICRO Corp. |
|
| CP01 | Change in the name or title of a patent holder | ||
| CX01 | Expiry of patent term |
Granted publication date: 20140507 |
|
| CX01 | Expiry of patent term |