CN108304022B - Overcurrent protection circuit of switching regulator - Google Patents
Overcurrent protection circuit of switching regulator Download PDFInfo
- Publication number
- CN108304022B CN108304022B CN201711376650.6A CN201711376650A CN108304022B CN 108304022 B CN108304022 B CN 108304022B CN 201711376650 A CN201711376650 A CN 201711376650A CN 108304022 B CN108304022 B CN 108304022B
- Authority
- CN
- China
- Prior art keywords
- signal
- output
- main circuit
- module
- overcurrent protection
- 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.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05F—SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
- G05F1/10—Regulating voltage or current
- G05F1/46—Regulating voltage or current wherein the variable actually regulated by the final control device is dc
- G05F1/56—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices
- G05F1/565—Regulating voltage or current wherein the variable actually regulated by the final control device is dc using semiconductor devices in series with the load as final control devices sensing a condition of the system or its load in addition to means responsive to deviations in the output of the system, e.g. current, voltage, power factor
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- General Physics & Mathematics (AREA)
- Radar, Positioning & Navigation (AREA)
- Automation & Control Theory (AREA)
- Dc-Dc Converters (AREA)
Abstract
The invention relates to the technical field of power electronics, in particular to an overcurrent protection circuit of a switching regulator, which comprises: a voltage reduction module; a first acquisition module; a second acquisition module; a third acquisition module; a comparison module; the comparison module compares the superposed signal of the feedback signal and the ramp signal with the acquired signal and outputs a comparison signal through a comparison output end; a pulse width modulation module; when the collected working current on the main circuit is greater than a preset value, the ratio of the output feedback signal to the working current on the main circuit is greater than 1, and when the collected working current on the main circuit is less than the preset value, the ratio is equal to 1; the over-current protection device has the advantages of strong over-current protection capability, high reaction speed and high reliability.
Description
Technical Field
The invention relates to the technical field of power electronics, in particular to an overcurrent protection circuit of a switching regulator.
Background
With the rapid development of microelectronic technology, the switching regulator has been widely used in various occasions due to the advantages of simple circuit structure, convenient adjustment, high reliability, etc., and the switching regulator usually adopts a pwm (pulse Width modulation) control mode, which has a good noise reduction advantage.
However, the conventional switching regulator controlled by the PWM technique is greatly affected by the load, and when the condition of overcurrent protection occurs in the whole circuit, the response speed of the overcurrent protection process is slow, which cannot meet the requirement of overcurrent protection, and the reliability of overcurrent protection is poor.
Disclosure of Invention
In view of the above problems, the present invention provides an overcurrent protection circuit of a switching regulator, including:
a voltage reduction module comprising:
a signal input for receiving an input signal and a signal output for outputting an output signal;
the main circuit is connected in series between the signal input end and the signal output end;
the first MOS tube and the second MOS tube are used for controlling the conduction of the main circuit;
the first acquisition module is connected with the signal output end to acquire the output signal of the signal output end and output an acquisition signal according to the output signal;
the second acquisition module is connected with the signal output end to acquire the output signal of the signal output end and output a ramp signal according to the output signal;
the third acquisition module is used for acquiring the working current on the main circuit in the voltage reduction module and outputting a feedback signal;
a comparison module comprising:
the positive phase input end is connected with the first acquisition module and used for receiving the acquisition signal;
the first reverse-phase input end is connected with the second acquisition module and used for receiving the ramp signal;
the second reverse-phase input end is connected with the third acquisition module and used for receiving the feedback signal;
a comparison output terminal;
the comparison module compares the superposed signal of the ramp signal and the feedback signal with the acquired signal and outputs a comparison signal through the comparison output end;
the pulse width modulation module is respectively connected with the comparison output end, the first MOS tube and the second MOS tube, and is used for receiving and generating a control signal with a corresponding duty ratio according to the comparison signal to control the first MOS tube and the second MOS tube;
when the collected working current on the main circuit is greater than a preset value, the ratio of the output feedback signal to the working current on the main circuit is greater than 1 by the third collection module; and when the collected working current on the main circuit is smaller than the preset value, the third collection module outputs a ratio of the feedback signal to the working current on the main circuit equal to 1.
The overcurrent protection circuit is characterized in that the preset value is greater than or equal to 125% -175% of a rated value of the working current on the main circuit.
The overcurrent protection circuit is characterized in that the preset value is greater than or equal to 150% of a rated value of the working current of the main circuit.
In the overcurrent protection circuit, the first acquisition module includes an error amplification unit, and is configured to compare the acquired output signal with a preset reference signal and amplify the output signal.
In the overcurrent protection circuit, the first acquisition module further includes a voltage stabilization unit, and the voltage stabilization unit is connected to the output port of the error amplification unit to stabilize the voltage of the amplified signal generated by the error amplification unit to form the acquisition signal.
In the overcurrent protection circuit, the voltage stabilizing unit includes a first compensation capacitor, a second compensation capacitor and a compensation resistor;
the first compensation capacitor is connected with the compensation resistor in series and then connected with the second compensation capacitor in parallel.
In the overcurrent protection circuit, the voltage reduction module includes an inductive resistor connected in series in the main circuit;
the third acquisition module acquires the induction voltage on the induction resistor and generates the feedback signal after multiplying the induction voltage by a feedback coefficient.
In the overcurrent protection circuit, the first MOS transistor and the second MOS transistor are both NMOS transistors.
Has the advantages that: the overcurrent protection circuit of the switching regulator provided by the invention has the advantages of strong overcurrent protection capability, high reaction speed and high reliability.
Drawings
Fig. 1 is a schematic structural diagram of an overcurrent protection circuit of a switching regulator according to an embodiment of the present invention;
fig. 2 is a schematic circuit diagram of a first acquisition module in an overcurrent protection circuit of a switching regulator according to an embodiment of the present invention;
fig. 3 is a schematic circuit diagram of a main circuit in an overcurrent protection circuit of the switching regulator according to an embodiment of the present invention;
fig. 4 is a waveform diagram of a signal output by a first acquisition circuit in an overcurrent protection circuit of a switching regulator according to an embodiment of the present invention;
fig. 5 is a waveform diagram of a superimposed signal in an overcurrent protection circuit of a switching regulator according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, in a preferred embodiment, an overcurrent protection circuit of a switching regulator is provided, which may include:
the voltage reducing module 10 includes:
a signal input terminal INT for receiving an input signal and a signal output terminal OUT for outputting an output signal;
a main circuit 11 connected in series between a signal input terminal INT and a signal output terminal OUT;
a first MOS transistor M1 and a second MOS transistor M2 for controlling the conduction of the main circuit 11;
the first acquisition module 21 is connected with the signal output end to acquire the output signal of the signal output end and output an acquisition signal according to the output signal;
the second acquisition module 22 is connected with the signal output end OUT to acquire an output signal of the signal output end OUT and output a ramp signal according to the output signal;
the third collecting module 23 is configured to collect the working current on the main circuit 11 in the voltage reducing module 10 and output a feedback signal;
a comparison module 30, comprising:
a positive phase input end connected to the first acquisition module 21 for receiving the acquisition signal;
a first inverting input terminal connected to the second collecting module 22 for receiving the ramp signal;
the second inverting input end is connected with the third acquisition module 23 and used for receiving the feedback signal;
a comparison output terminal Cout;
the comparison module 30 compares the superposed signal of the ramp signal and the feedback signal with the collected signal, and outputs a comparison signal through a comparison output terminal Cout;
the pulse width modulation module 40 is respectively connected with the comparison output end Cout, the first MOS transistor and the M1 second MOS transistor M2, and is used for receiving and generating a control signal corresponding to the duty ratio according to the comparison signal to control the first MOS transistor M1 and the second MOS transistor M2;
when the collected working current on the main circuit is greater than a preset value, the ratio of the output feedback signal to the working current on the main circuit is greater than 1 by the third collection module; when the collected working current on the main circuit is smaller than a preset value, the ratio of the output feedback signal to the working current on the main circuit is equal to 1.
In the above technical solution, the first MOS transistor M1 and the second MOS transistor M2 may be respectively connected to the main circuit 11 and configured to be turned on under the control of a control signal, so as to control the turning on of the main circuit 11, where the control signal is a pulse signal with a specific duty ratio, and the first MOS transistor M1 and the second MOS transistor M2 can be sequentially turned on in each time period, so as to control the current/voltage of the main circuit through different duty ratios.
In a preferred embodiment, the preset value is greater than or equal to 125% -175% of the nominal value of the operating current on the main circuit 11.
In the above technical solution, for example, the preset value may be 135%, 140%, 145%, 155%, 160%, 165% of a rated value of the operating current on the main circuit 11.
In the above embodiment, preferably, the preset value is greater than or equal to 150% of a rated value of the operating current on the main circuit.
In the above technical solution, if the working current on the main circuit 11 collected by the third collecting module 23 is greater than 150% of the rated value, it is determined that the main circuit 11 needs overcurrent protection, and for the continuously rising working current, the ratio of the feedback signal to the working current on the main circuit 11 is greater than 1, that is, the feedback signal will continuously climb, so that the comparing module 30 can quickly reverse to form overcurrent protection; when the working current tends to be stable, the ratio of the feedback signal to the working current on the main circuit 11 is restored to 1.
In the above technical solution, when the ratio of the feedback signal to the working current on the main circuit 11 is greater than 1, the specific ratio may be a fixed coefficient value greater than 1, or may be a continuously increasing variable coefficient value.
As shown in fig. 2, in a preferred embodiment, the first acquisition module 21 includes an error amplifying unit gm for comparing the acquired output signal with a predetermined reference signal Vref and then amplifying the output signal.
In the above technical solution, the collected output signal enters from the input port In 1; after the input signal enters, the voltage Veain entering the inverting input end of the error amplification unit gm can be formed through a voltage division unit; the voltage dividing unit in fig. 2 is composed of a resistor R1 and a resistor R2 connected in series, the resistor R2 may be connected in parallel with a capacitor C2, and one end of the resistor R1, which is not connected with the resistor R2, may be grounded.
In the above embodiment, preferably, the first acquisition module 21 may further include a voltage stabilizing unit, and the voltage stabilizing unit is connected to an output port of the error amplifying unit gm to stabilize the voltage of the amplified signal generated by the error amplifying unit 21 to form the acquired signal.
In the above technical solution, the collected signal generated after voltage stabilization is output from the output port Ou 1.
In the above embodiment, preferably, the voltage stabilizing unit includes a first compensation capacitor Cth, a second compensation capacitor Cthp, and a compensation resistor Rth;
the first compensation capacitor Cth is connected in series with the compensation resistor Rth and then connected in parallel with the second compensation capacitor Cthp.
In the above technical solution, the capacitance values of the first compensation capacitor Cth and the second compensation capacitor Cthp may be different; the voltage regulation unit may further include a resistor R0 having one end connected to ground.
As shown in fig. 3, in a preferred embodiment, the voltage dropping module 10 includes an inductive resistor Rsense connected in series in the main circuit 11;
the third collecting module 23 collects the induced voltage of the inductive resistor Rsense, and multiplies the induced voltage by a feedback coefficient to generate a feedback signal.
In the above technical solution, an input signal input from the signal input terminal INT enters the main circuit 11 from the input port In2 of the main circuit 11 after passing through the first MOS transistor M1, and is output from the output port Ou2 after passing through the rectifying inductor L; the sense resistor Rsense may be connected in series after the rectifier inductor L.
In a preferred embodiment, the first MOS transistor M1 and the second MOS transistor M2 are both NMOS transistors, but this is only a preferred case, and both of them may be PMOS transistors, or one of them is PMOS and the other is NMOS transistors.
Specifically, as shown in fig. 4, VEAO represents the waveform of the comparison signal output by the comparison module 30, Vref represents the waveform of the reference voltage of the comparison module 30, and the value of the comparison signal output by the comparison module 30 continuously and rapidly rises due to the continuous rise of the operating voltage; as shown in fig. 5, VCS in fig. 5 represents the waveform of the superimposed signal, and the amplitude of the superimposed signal has a trend of significantly increasing rapidly, so that the output of the comparison module 30 can be rapidly inverted, thereby ensuring the rapidity and effectiveness of the overcurrent protection process.
In summary, the over-current protection circuit of the switching regulator provided by the present invention includes: a voltage reduction module; a first acquisition module; a second acquisition module; a third acquisition module; a comparison module; the comparison module compares the superposed signal of the feedback signal and the ramp signal with the acquired signal and outputs a comparison signal through a comparison output end; a pulse width modulation module; when the collected working current on the main circuit is greater than a preset value, the ratio of the output feedback signal to the working current on the main circuit is greater than 1 by the third collection module; when the collected working current on the main circuit is smaller than a preset value, the ratio of the output feedback signal to the working current on the main circuit is equal to 1 by the third collection module; the over-current protection device has the advantages of strong over-current protection capability, high reaction speed and high reliability.
While the specification concludes with claims defining exemplary embodiments of particular structures for practicing the invention, it is believed that other modifications will be made in the spirit of the invention. While the above invention sets forth presently preferred embodiments, these are not intended as limitations.
Various alterations and modifications will no doubt become apparent to those skilled in the art after having read the above description. Therefore, the appended claims should be construed to cover all such variations and modifications as fall within the true spirit and scope of the invention. Any and all equivalent ranges and contents within the scope of the claims should be considered to be within the intent and scope of the present invention.
Claims (8)
1. An overcurrent protection circuit of a switching regulator, comprising:
a voltage reduction module comprising:
a signal input for receiving an input signal and a signal output for outputting an output signal;
the main circuit is connected in series between the signal input end and the signal output end;
the first MOS tube and the second MOS tube are used for controlling the conduction of the main circuit;
the first acquisition module is connected with the signal output end to acquire the output signal of the signal output end and output an acquisition signal according to the output signal;
the second acquisition module is connected with the signal output end to acquire the output signal of the signal output end and output a ramp signal according to the output signal;
the third acquisition module is used for acquiring the working current on the main circuit in the voltage reduction module and outputting a feedback signal;
a comparison module comprising:
the positive phase input end is connected with the first acquisition module and used for receiving the acquisition signal;
the first reverse-phase input end is connected with the second acquisition module and used for receiving the ramp signal;
the second reverse-phase input end is connected with the third acquisition module and used for receiving the feedback signal;
a comparison output terminal;
the comparison module compares the superposed signal of the ramp signal and the feedback signal with the acquired signal and outputs a comparison signal through the comparison output end;
the pulse width modulation module is respectively connected with the comparison output end, the first MOS tube and the second MOS tube, and is used for receiving and generating a control signal with a corresponding duty ratio according to the comparison signal to control the first MOS tube and the second MOS tube;
when the collected working current on the main circuit is greater than a preset value, the ratio of the output feedback signal to the working current on the main circuit is greater than 1 by the third collection module; when the collected working current on the main circuit is smaller than the preset value, the ratio of the output feedback signal to the working current on the main circuit is equal to 1 by the third collection module;
the voltage reduction module comprises an induction resistor connected in series in the main circuit;
an input signal input by the signal input end enters the main circuit from the input port of the main circuit after passing through the first MOS tube, and is output from the signal output end after passing through the rectifying inductor; the induction resistor is connected in series behind the rectifying inductor.
2. The overcurrent protection circuit of claim 1, the preset value being greater than or equal to 125-175% of a rated value of operating current on the main circuit.
3. The overcurrent protection circuit of claim 2 wherein the predetermined value is greater than or equal to 150% of a nominal value of operating current on the main circuit.
4. The overcurrent protection circuit of claim 1, wherein the first acquisition module comprises an error amplification unit configured to compare the acquired output signal with a predetermined reference signal and amplify the output signal.
5. The overcurrent protection circuit of claim 4, wherein the first acquisition module further comprises a voltage stabilization unit, and the voltage stabilization unit is connected to an output port of the error amplification unit to stabilize the amplified signal generated by the error amplification unit to form the acquisition signal.
6. The overcurrent protection circuit of claim 5, wherein the voltage regulation unit comprises a first compensation capacitor, a second compensation capacitor and a compensation resistor;
the first compensation capacitor is connected with the compensation resistor in series and then connected with the second compensation capacitor in parallel.
7. The overcurrent protection circuit as claimed in claim 1, wherein the voltage dropping module comprises an inductive resistor connected in series in the main circuit;
the third acquisition module acquires the induction voltage on the induction resistor and generates the feedback signal after multiplying the induction voltage by a feedback coefficient.
8. The overcurrent protection circuit of claim 1, wherein the first MOS transistor and the second MOS transistor are both NMOS transistors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711376650.6A CN108304022B (en) | 2017-12-19 | 2017-12-19 | Overcurrent protection circuit of switching regulator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711376650.6A CN108304022B (en) | 2017-12-19 | 2017-12-19 | Overcurrent protection circuit of switching regulator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108304022A CN108304022A (en) | 2018-07-20 |
| CN108304022B true CN108304022B (en) | 2020-12-25 |
Family
ID=62870704
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711376650.6A Active CN108304022B (en) | 2017-12-19 | 2017-12-19 | Overcurrent protection circuit of switching regulator |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108304022B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI684087B (en) * | 2019-03-11 | 2020-02-01 | 聚積科技股份有限公司 | Voltage stabilizing system |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6933710B2 (en) * | 2002-02-19 | 2005-08-23 | Fairchild Semiconductor Corporation | Soft start techniques for control loops that regulate DC/DC converters |
| CN1897440A (en) * | 2006-06-30 | 2007-01-17 | 北京中星微电子有限公司 | Circuit for controlling switch power supply |
| CN101689805A (en) * | 2007-05-29 | 2010-03-31 | 凌特公司 | The improved Controlled in Current Mode and Based of switching regulaor |
| CN104167924A (en) * | 2014-08-13 | 2014-11-26 | 南京创佳通讯电源设备厂 | Double-current control circuit of switching power supply |
| CN106612070A (en) * | 2015-10-22 | 2017-05-03 | 深圳市中兴微电子技术有限公司 | Load transient response enhancement method and system for voltage-mode buck converter |
| CN106911251A (en) * | 2015-12-22 | 2017-06-30 | 上海贝岭股份有限公司 | Boost power converter |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9678521B2 (en) * | 2013-04-15 | 2017-06-13 | Virginia Tech Intellectual Properties, Inc. | External ramp autotuning for current mode control of switching converter |
-
2017
- 2017-12-19 CN CN201711376650.6A patent/CN108304022B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6933710B2 (en) * | 2002-02-19 | 2005-08-23 | Fairchild Semiconductor Corporation | Soft start techniques for control loops that regulate DC/DC converters |
| CN1897440A (en) * | 2006-06-30 | 2007-01-17 | 北京中星微电子有限公司 | Circuit for controlling switch power supply |
| CN101689805A (en) * | 2007-05-29 | 2010-03-31 | 凌特公司 | The improved Controlled in Current Mode and Based of switching regulaor |
| CN104167924A (en) * | 2014-08-13 | 2014-11-26 | 南京创佳通讯电源设备厂 | Double-current control circuit of switching power supply |
| CN106612070A (en) * | 2015-10-22 | 2017-05-03 | 深圳市中兴微电子技术有限公司 | Load transient response enhancement method and system for voltage-mode buck converter |
| CN106911251A (en) * | 2015-12-22 | 2017-06-30 | 上海贝岭股份有限公司 | Boost power converter |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108304022A (en) | 2018-07-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US9529373B2 (en) | Switching regulator and control circuit and control method therefor | |
| US6696882B1 (en) | Transient override circuit for a voltage regulator circuit | |
| US8525505B2 (en) | PWM controller and control method for a DC-DC voltage converter | |
| US20140021929A1 (en) | Multi-phase switching regulator and droop circuit therefor | |
| US9647552B2 (en) | Constant on time switching converter with DC calibration | |
| US9413240B2 (en) | Power converter and controller device | |
| JP2003061350A (en) | Switching power supply | |
| US8587275B2 (en) | Instantaneous average current measurement method | |
| JP2009118578A (en) | Power supply device | |
| US20170133919A1 (en) | Dual-phase dc-dc converter with phase lock-up and the method thereof | |
| TW201413411A (en) | DC-DC controller | |
| CN108566073B (en) | Transient response circuit of switching regulator | |
| CN108304022B (en) | Overcurrent protection circuit of switching regulator | |
| US8188719B2 (en) | Voltage regulator | |
| CN108306504B (en) | Transient response circuit of switching regulator | |
| CN109936283B (en) | Soft start circuit of switching regulator | |
| US6552579B1 (en) | Fuel gauge power switch with current sense | |
| US10418896B2 (en) | Switching regulator including an offset enabled comparison circuit | |
| US7446516B2 (en) | DC/DC converter with improved stability | |
| JP2010220454A (en) | Dc-dc converter and semiconductor integrated circuit for control | |
| US9952616B2 (en) | Differential circuit including a current mirror | |
| JP2017529822A (en) | A device for generating a constant DC load current | |
| WO2019120006A1 (en) | Transient response circuit of switching regulator | |
| US8324879B2 (en) | Power inverter control device for switching point determination | |
| EP2690776B1 (en) | Power conversion device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |