CN115378246A - Switching power supply with overshoot protection - Google Patents
Switching power supply with overshoot protection Download PDFInfo
- Publication number
- CN115378246A CN115378246A CN202211073907.1A CN202211073907A CN115378246A CN 115378246 A CN115378246 A CN 115378246A CN 202211073907 A CN202211073907 A CN 202211073907A CN 115378246 A CN115378246 A CN 115378246A
- Authority
- CN
- China
- Prior art keywords
- voltage
- switch
- compensation
- control signal
- 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.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/06—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider
- H02M3/07—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider using capacitors charged and discharged alternately by semiconductor devices with control electrode, e.g. charge pumps
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/10—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers
- H02H7/12—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers
- H02H7/1213—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for converters; for rectifiers for static converters or rectifiers for DC-DC converters
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/0003—Details of control, feedback or regulation circuits
- H02M1/0038—Circuits or arrangements for suppressing, e.g. by masking incorrect turn-on or turn-off signals, e.g. due to current spikes in current mode control
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
- H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M1/00—Details of apparatus for conversion
- H02M1/32—Means for protecting converters other than automatic disconnection
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
- H02M3/158—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators including plural semiconductor devices as final control devices for a single load
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Abstract
The present disclosure provides a switching power supply with overshoot protection. The switching power supply includes: a voltage step-down circuit including a first switch and a second switch connected in series, configured to charge or discharge an inductor by alternately turning on the first switch and the second switch to step down an input voltage to an output voltage; an overshoot protection circuit configured to generate a compensation voltage based on the input voltage and a set value of the output voltage; and a switch control circuit generating a switch control signal to control the first switch and the second switch to be alternately turned on based on the compensation voltage and the input voltage.
Description
Technical Field
The present disclosure relates to the field of power supply and, more particularly, to a switching power supply with overshoot protection.
Background
The switching power supply converts an input voltage provided by a power supply device (such as a battery or an adapter) on an input side into an output voltage suitable for a load on an output side by controlling the on and off of a switching tube so that the load can normally operate. Currently, switching power supplies have been widely used in power supply applications for various electronic devices, such as in the automotive electronics field. In these applications, the input voltage often varies dramatically, causing abrupt changes in the output current and output voltage. In particular, in the case of a rapid rise after a rapid fall in the input voltage, the output voltage and the output current may exceed their set values due to the follow-up delay, which is also referred to as overshoot.
The overshoot of the output voltage and the output current may damage the switching power supply and even the electronic components of the load, which may affect the service life of the circuit or the chip.
Disclosure of Invention
In view of the above problems, the present disclosure provides a switching power supply with overshoot protection, which can prevent overshoot of an output voltage and an output current when an input voltage abruptly changes.
In one aspect of the disclosure, a switching power supply with overshoot protection is provided. The switching power supply includes: <xnotran> , , , ; </xnotran> An overshoot protection circuit configured to generate a compensation voltage based on the input voltage and a set value of the output voltage; and a switch control circuit generating a switch control signal to control the first switch and the second switch to be alternately turned on based on the compensation voltage and the input voltage.
In some embodiments, the compensation voltage comprises a first compensation voltage and a second compensation voltage, and the first compensation voltage is higher than the second compensation voltage, wherein the overshoot protection circuit is configured to: generating the first compensation voltage in response to the input voltage being less than or equal to a set value of the output voltage; and generating the second compensation voltage in response to the input voltage being higher than a set value of the output voltage.
In some embodiments, the overshoot protection circuit comprises: a protection voltage generation circuit configured to generate a protection voltage based on a feedback voltage associated with the output voltage, a predetermined reference voltage, and a predetermined current source; and a compensation voltage generation circuit for generating a compensation voltage, configured to generate the compensation voltage based on the protection voltage, the predetermined reference voltage, and the feedback voltage.
In some embodiments, the protection voltage generation circuit includes: a comparator having one input terminal receiving a first boosted value of the feedback voltage, the other input end receives the predetermined reference voltage and generates a comparison signal based on the first boosting value and the predetermined reference voltage; a voltage buffer boosting the feedback voltage to a second boosted voltage value upon triggering of the comparison signal; and a third switch turned on under control of a third switch control signal to provide the second boosted value as the protection voltage, wherein the third switch control signal is obtained by an and operation of the comparison signal and a control signal.
In some embodiments, the compensation voltage generation circuit is configured to: in response to the protection voltage being less than the predetermined reference voltage, generating the first compensation voltage based on the protection voltage and the feedback voltage; and in response to the protection voltage being greater than or equal to the predetermined reference voltage, generating the second compensation voltage based on the predetermined reference voltage and the feedback voltage.
In some embodiments, the switch control circuit comprises: an oscillator for generating an operation clock signal and a slope compensation signal having the same frequency; a pulse width modulation signal generator comparing the compensation voltage with a sum of the sampled signal of the input voltage and the slope compensation signal to generate a pulse width modulation signal; and a switching control signal generating circuit that generates the switching control signal based on the operation clock signal and the pulse width modulation signal.
In some embodiments, the switch control signal includes a first switch control signal and a second switch control signal, and the control signal generation circuit includes: a clock input end of the D flip-flop receives the working clock signal, the D flip-flop is triggered by a rising edge of the working clock signal to output the first switch control signal to turn on the first switch and turn off the second switch, a reset end of the D flip-flop receives the pulse width modulation signal, and the D flip-flop is set to output the second switch control signal to turn on the second switch and turn off the first switch.
In some embodiments, the voltage reduction circuit further comprises: a voltage divider circuit configured to divide the output voltage to generate a feedback voltage associated with the output voltage.
By using the scheme disclosed by the invention, the soft start voltage is adjusted by detecting the change of the output voltage, so that the output voltage is smoothly increased, the overshoot of the output voltage and the output current is avoided, and the temperature work of the load is further ensured.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.
Drawings
The above and other objects, structures and features of the present disclosure will become more apparent from the following detailed description when read in conjunction with the accompanying drawings. In the drawings, several embodiments of the present disclosure are shown by way of example and not limitation. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale.
Fig. 1 shows a schematic diagram of a switching power supply according to the prior art.
FIG. 2 shows a diagram according to the prior art waveform timing diagram of the switching power supply.
Fig. 3 shows a schematic block diagram of a switching power supply with overshoot protection according to an embodiment of the present disclosure.
Fig. 4 schematically illustrates a detailed circuit diagram of a switching power supply with overshoot protection, according to some embodiments of the present disclosure.
Fig. 5 schematically illustrates an operation waveform timing diagram of a switching power supply with overshoot protection according to an embodiment of the disclosure.
Detailed Description
Embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While certain embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be construed as limited to the embodiments set forth herein, but rather are provided for a more complete and thorough understanding of the present disclosure. It should be understood that the drawings and the embodiments of the disclosure are for illustration purposes only and are not intended to limit the scope of the disclosure. It may be evident in some or all instances that any of the embodiments described below may be practiced without the specific design details described below. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more embodiments.
In the description of the embodiments of the present disclosure, the expression "comprising" and its similar terms should be understood as open-ended, i.e., "including but not limited to". The expression "based on" should be understood as "based at least in part on". The expression "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The expressions "first", "second", etc. may refer to different or the same object. Other explicit and implicit definitions are also possible below.
Fig. 1 shows a schematic diagram of a switching power supply 10 according to the prior art. Fig. 2 shows a waveform timing diagram of a switching power supply according to the prior art.
As shown in fig. 1, the switching power supply 10 may include a voltage-reducing circuit 110, and the voltage-reducing circuit 110 may reduce an input voltage Vin to an output voltage Vout. For example, the buck circuit 110 may alternately turn on two switches to charge and discharge an inductor therein to implement buck conversion.
The switching power supply 10 may further include a switching control circuit 130, wherein the switching control circuit 130 may compare a feedback voltage Vfb associated with the output voltage Vout with a predetermined reference voltage Vref, and generate a compensation voltage Vcomp according to the comparison result. The compensation voltage Vcomp, together with the sampled voltage Vsense of the input voltage Vin, determines the on and off of two switches in the buck circuit 110 under the action of the clock signal CLK generated by the switch control circuit 130.
As shown in fig. 2, it is assumed that at time t1, the input voltage Vin starts to rapidly drop. After time t2, the input voltage Vin may drop below the set value V0 of the output voltage Vout. Thereafter, the output voltage Vout will follow the input voltage Vin and the feedback voltage Vfb will decrease to be less than the predetermined reference voltage Vref, so that the compensation voltage Vcomp will increase to the maximum value rapidly.
If the input voltage Vin starts to increase suddenly again shortly after the input voltage Vin decreases to the minimum value (time t 3) (time t 4), at this time, the feedback voltage Vfb is still less than the predetermined reference voltage Vref because the output voltage Vout cannot suddenly change, and the compensation voltage Vcomp continues to be kept high to continuously increase the output voltage Vout.
At the time t5 when the output voltage Vout reaches its set value V0, the feedback voltage Vfb starts to be greater than the reference voltage Vref, the compensation voltage Vcomp starts to decrease, and the control loop adjusts the feedback voltage Vfb to adjust the compensation voltage Vcomp to a stable value. During this process, the output voltage Vout may overshoot (as indicated by reference numeral 202 in fig. 2), and during the rising process of the output voltage Vout (for example, during the period from time t4 to time t 5), the output current Iout may overshoot (as indicated by reference numeral 204 in fig. 2). Overshoot of both the output voltage Vout and the output current Iout is undesirable and can cause damage to the entire switching power supply and even the load.
It can be seen that the main reason for the overshoot is that the output voltage Vout cannot abruptly change, so that the feedback voltage Vfb following the change thereof is relatively delayed, and thus the compensation voltage Vcomp determined by the feedback voltage Vfb and the predetermined reference voltage Vref is relatively delayed, so that the compensation voltage Vcomp may still be compensated when the output voltage Vout has reached its set value V0, thereby generating the output voltage overshoot.
In view of the above problem, in the embodiment of the disclosure, the soft-start voltage is adjusted by detecting the change of the output voltage Vout (i.e. the generation of the compensation voltage Vcomp), so as to avoid that the compensation voltage Vcomp is still compensated when the output voltage Vout has reached the set value V0.
Fig. 3 shows a schematic block diagram of a switching power supply 20 with overshoot protection according to an embodiment of the present disclosure. The switching power supply 20 may down-convert an input voltage Vin provided by a power supply (not shown) to an output voltage Vout to supply power to a load (not shown). The switching power supply of fig. 3 is a typical peak current and output voltage dual loop controlled buck converter.
Similar to the switching power supply 10 in fig. 1, the switching power supply 20 may also include a voltage-decreasing circuit 210 and a switch control circuit 230 similar to the voltage-decreasing circuit 110 and the switch control circuit 130. Unlike the switching power supply 10 in fig. 1, the switching power supply 20 further includes an overshoot protection circuit 220.
The voltage dropping circuit 210 includes a first switch Q1 and a second switch Q2 (shown in fig. 4) connected in series, and is configured to charge or discharge an inductor L by alternately turning on the first switch Q1 and the second switch Q2 to drop an input voltage Vin to an output voltage Vout.
The overshoot protection circuit 220 is configured to generate the compensation voltage Vcomp based on the input voltage Vin and the set value V0 of the output voltage Vout.
Here, in particular, the compensation voltage Vcomp may include a first compensation voltage Vcomp1 and a second compensation voltage Vcomp2. The overshoot protection circuit 220 is configured to generate a first compensation voltage Vcomp1 when the input voltage Vin is lower than or equal to a set value V0 of the output voltage Vout, and generate a second compensation voltage Vcomp2 when the input voltage Vin is higher than the set value V0 of the output voltage Vout. Here, the first compensation voltage Vcomp1 is higher than the second compensation voltage Vcomp2. In this way, the overshoot protection circuit 220 may generate a higher compensation voltage Vcomp when the input voltage Vin is lower than or equal to the set value V0 of the output voltage Vout, and the overshoot protection circuit 220 may generate a lower compensation voltage Vcomp when the input voltage Vin rises higher than the set value V0 of the output voltage Vout again, thereby preventing the output voltage Vout from overshooting due to the higher compensation voltage Vcomp.
Here, the setting value V0 may have different values depending on different applications of the switching power supply 20, and the setting value V0 of the output voltage Vout may be provided by an internal or external voltage source, which is not described herein again.
The switch control circuit 230 may generate a switch control signal to control the first switch Q1 and the second switch Q2 to be alternately turned on based on the compensation voltage Vcomp and the input voltage Vin.
Fig. 4 illustrates a detailed circuit diagram of the switching power supply 20 with overshoot protection according to some embodiments of the present disclosure.
As shown in fig. 4, the voltage-reducing circuit 210 includes a first switch Q1 and a second switch Q2 connected in series to ground, and a junction of the first switch Q1 and the second switch Q2 is connected in series with an inductor L and a capacitor Co. Under the control of the switch control signal from the switch control circuit 230, the first switch Q1 and the second switch Q2 are alternately turned on to charge and discharge the inductor L, thereby dropping the input voltage Vin to the output voltage Vout. The first switch Q1 and the second switch Q2 may be implemented using field effect transistors (MOSFETs). For example, as shown in fig. 4, the first switch Q1 and the second switch Q2 are both implemented using N-type MOSFETs (NMOS transistors), wherein the gate of the first switch Q1 is connected to a switch control signal (more specifically, the first switch control signal HSD, described below), the drain is connected to the input voltage Vin, and the source is connected to the drain of the second switch Q2. The gate of the second switch Q2 is connected to a switch control signal (more specifically, a second switch control signal LSD, described below), the drain is connected to the source of the first switch Q1, and the source is Grounded (GND). However, it will be understood by those skilled in the art that the present invention is not limited thereto, and the first switch Q1 and the second switch Q2 may be implemented using various other diodes, bipolar transistors or other electronic devices, or a combination thereof.
In addition, the voltage step-down circuit 210 further includes a resistor Ro connected in parallel with the capacitor Co to ground, so as to protect charging and discharging of the capacitor Co.
When the first switch Q1 is turned on, the input voltage Vin charges the inductor L and the capacitor Co to generate the output voltage Vout to supply power to the load. During this time, the second switch Q2 is turned off, and the current flowing through the inductor L is equal to the current flowing through the first switch Q1, and gradually increases as time passes. When the first switch Q1 is turned off and the second switch Q2 is turned on, the inductor L and the capacitor Co supply power to the load, and the current flowing through the inductor L gradually decreases. Thus, by alternately turning on the first switch Q1 and the second switch Q2, the voltage dropping circuit 210 may drop the input voltage Vin to the output voltage Vout to supply power to the load.
In some embodiments, the voltage-reducing circuit 210 may further include a voltage-dividing circuit for dividing the output voltage Vout to generate a feedback voltage Vfb associated with the output voltage Vout. The voltage dividing circuit may be constituted by, for example, resistors Rf1 and Rf2 connected in series, one end connected to the inductor L, receiving the output voltage Vout, the other end grounded, and the voltage of the connection point of the resistors Rf1 and Rf2 as the feedback voltage Vfb to be input to the overshoot protection circuit 220.
The overshoot protection circuit 220 may include a protection voltage generation circuit 222, and the protection voltage generation circuit 222 is configured to generate the protection voltage Vss based on the feedback voltage Vfb associated with the output voltage Vout, the predetermined reference voltage Vref, and the predetermined current source Iss. Here, the predetermined reference voltage Vref may have different values depending on application parameters of the switching power supply 20, and may be provided by an internal or external voltage source, which will not be described in detail herein.
The overshoot protection circuit 220 may further include a compensation voltage generation circuit 224, the compensation voltage generation circuit 224 being configured to generate a compensation voltage Vcomp based on the protection voltage Vss, the predetermined reference voltage Vref, and the feedback voltage Vfb.
In some embodiments, the protection voltage generation circuit 222 may include a comparator CMP1, a voltage buffer Buf1, and a third switch K1.
One input terminal of the comparator CMP1 receives the first boosted value Va of the feedback voltage Vfb, the other input terminal receives the predetermined reference voltage Vref, and generates the comparison voltage FB _ L based on the first boosted value Va and the predetermined reference voltage Vref. Here, the first boosted value Va of the feedback voltage Vfb may be obtained by boosting the feedback voltage Vfb by a fixed voltage source os1, for example, a weak voltage source that can supply a voltage Vos1 of several tens of mv, for example. The first boost value Va may be expressed as Va = Vfb + Vos1.
The voltage buffer Buf1 boosts the feedback voltage Vfb to the second boosted value Vb triggered by the comparison voltage FB _ L (for example, when the comparison voltage FB _ L changes from a low level to a high level). Here, similarly, the second boosted voltage value Vb may also be obtained by boosting the feedback voltage Vfb by another fixed voltage source os2, which fixed voltage source os2 may provide, for example, a voltage Vos2 of several tens of mv, which may be the same as or different from the fixed voltage source os1. The second boost value may be represented as Vb = Vfb + Vos2.
The third switch K1 may be turned on under the control of the third switch control signal EN _ K to provide the second boosted value Vb as the protection voltage Vss, i.e., vss = Vb = Vfb + Vos2. Here, the third switch control signal EN _ K may be obtained by performing an and operation on the comparison voltage FB _ L and the control signal LDO _ mode by the and gate I1, for example.
The compensation voltage generation circuit 224 is configured to compare the protection voltage Vss with a predetermined reference voltage Vref, and generate the compensation voltage Vcomp based on the comparison result.
Specifically, if the protection voltage Vss is less than the predetermined reference voltage Vref, the compensation voltage generation circuit 224 may generate the first compensation voltage Vcomp1 based on the protection voltage Vss and the feedback voltage Vfb; the compensation voltage generation circuit 224 may generate the second compensation voltage Vcomp2 based on the predetermined reference voltage Vref and the feedback voltage Vfb if the protection voltage Vss is greater than or equal to the predetermined reference voltage Vref. Here, the compensation voltage generation circuit 224 may be realized, for example, by an Error Amplifier (EA) having two positive input terminals connected to the protection voltage Vss and the predetermined reference voltage Vref, respectively, and a negative input terminal connected to the feedback voltage Vfb, as shown in fig. 4.
In this way, it is possible to generate different protection voltages Vss with the change of the output voltage Vout and to change the generation manner of the compensation voltage Vcomp with the magnitude of the protection voltage Vss, thereby avoiding that the compensation voltage Vcomp is still compensating for the output voltage Vout when it has reached the set value V0.
In some embodiments, the switch control circuit 230 may include an oscillator 232, a pulse width modulation signal generator 234, and a switch control signal generation circuit 236.
The oscillator 232 is used for generating the operation clock signal CLK and the slope compensation signal Ramp. The Ramp compensation signal Ramp has the same frequency as the operating clock signal CLK, and has a Ramp waveform with a different waveform.
The pulse width modulation signal generator 234 may compare the compensation voltage Vcomp with the sum of the Ramp compensation signal Ramp and the sampling signal Vsense of the input voltage Vin to generate the pulse width modulation signal PWM. Here, the sampling signal Vsense of the input voltage Vin may be obtained by sampling the input voltage Vin every time the first switch Q1 is turned on. By adding the slope compensation signal Ramp to the sampling signal Vsense of the input voltage Vin and comparing the added slope compensation signal Ramp with the compensation voltage Vcomp, subharmonic oscillation at a high duty cycle can be avoided, and the anti-noise performance can be improved.
The switching control signal generating circuit 236 may generate the switching control signal based on the operation clock signal CLK and the pulse width modulation signal PWM.
In some embodiments, the switch control signal may include a first switch control signal and a second switch control signal. The first switch control signal is used to turn on the first switch Q1 and turn off the second switch Q2, and the second switch control signal is used to turn on the second switch Q2 and turn off the first switch Q1.
In some embodiments, the switch control signal generation circuit 236 may include a D flip-flop DFF, as shown in fig. 4. The clock input terminal (CLK) of the D flip-flop DFF receives the operating clock signal CLK, and is triggered by a rising edge of the operating clock signal CLK to output the first switch control signal HSD. A RESET terminal (RESET) of the D flip-flop DFF receives a pulse width modulation signal PWM that sets the D flip-flop DFF to output a second switching control signal LSD. Specifically, as shown in fig. 4, at the time of the rising edge of the clock signal CLK, the output terminal Q of the D flip-flop DFF becomes high level, thereby outputting the first switch control signal HSD of high level to drive the first switch Q1 to be turned on, and at the same time, the output terminal XQ (which is the inverse of the output terminal Q) becomes low level, that is, the second switch control signal LSD is low to turn off the second switch Q2. When the pulse width modulation signal PWM changes to the high level, the D flip-flop DFF is set, and at this time, the output terminal Q changes to the low level, so that the first switch control signal HSD of the low level is output to drive the first switch Q1 to be turned off, and at the same time, the output terminal XQ changes to the high level, that is, the second switch control signal LSD becomes high to drive the second switch Q2 to be turned on.
Fig. 5 schematically shows an operation waveform timing diagram of the switching power supply 20 with overshoot protection according to the embodiment of the present disclosure.
As shown in fig. 5, after the switching power supply 20 starts to start up, the current source Iss charges the capacitance Css, the protection voltage Vss rises from zero, and the feedback voltage Vfb rises with the protection voltage Vss.
At time t1', the protection voltage Vss rises above the predetermined reference voltage Vref, at which point the magnitude of the feedback voltage Vfb starts to be determined by the predetermined reference voltage Vref (i.e., vfb = Vref, as shown), while the protection voltage Vss may continue to rise until it approaches the voltage of the current source Iss. Meanwhile, since Vfb > Vref-Vos1, va > Vref, the comparison voltage FB _ L goes from high to low.
Assuming that the input voltage Vin suddenly changes from high to low at a time t2' after the output voltage Vout is at the set value V0, and drops below the set value V0 of the output voltage Vout, the feedback voltage Vfb starts to be smaller than the predetermined reference voltage Vref.
When the feedback voltage Vfb decreases below the predetermined reference voltage Vref, the compensation voltage Vcomp starts to rise from a low level to a high level. When the feedback voltage Vfb continues to decrease below Vref-Vos1 (time t 3'), the comparator CMP1 starts to operate, the comparison voltage FB _ L changes from low to high, and the trigger control signal LDO _ mode is also at a high level because the input voltage Vin is less than the set value V0 of the output voltage Vout. At this time, the voltage buffer Buf1 is enabled, and outputs the voltage Vb, vb = Vfb + Vos2. At this time, since the input voltage Vin is lower than the set value V0 of the output voltage Vout, the first switch Q1 is turned on, and thus the final output voltage Vout is close to equal to the input voltage Vin. At this time, due to the voltage dividing action of the resistors Rf1 and Rf2, the feedback voltage Vfb reaches a substantially stable voltage value Vfb0, which can be expressed as:
Vfb0＝Rf2/(Rf1+Rf2)*Vout＝Rf2/(Rf1+Rf2)*Vin
at this time, the first switch Q1 is kept normally open, the control signal LDO _ mode is high, the comparison signal FB _ L is also high, the third switch control signal EN _ K is at a high level through the and gate I1, and the third switch K1 is in a conducting state. Since the current capability of the current source Iss is weak, typically in the nA level, and the output driving capability of the voltage buffer Buf1 is strong, the protection voltage Vss is forcibly set to Vss = Vb = Vfb0+ Vos2.
After that, assuming that the input voltage Vin suddenly and rapidly rises to the normal voltage at time t4', the first switch Q1 is turned off, and the control signal LDO _ mode goes from high to low when the input voltage Vin rises higher than the output voltage Vout. At this time, under the action of the and gate I1, the third switch control signal EN _ K becomes low level, the third switch K1 is turned off, the protection voltage Vss starts to rise slowly from Vfb0+ Vos2, the feedback voltage Vfb will also rise slowly along with the voltage of the protection voltage Vss, and thus the compensation voltage Vcomp will be lowered to a reasonable value in the process of rising the feedback voltage Vfb, and overshoot of the output current Iout and the output voltage Vout will not occur.
By utilizing the embodiment of the disclosure, the soft start voltage is adjusted by detecting the change of the output voltage, so that the output voltage is smoothly increased, the overshoot of the output voltage and the output current is avoided, and the temperature work of the load is further ensured.
Further, the present disclosure provides various example embodiments, as described and as shown in the accompanying drawings. However, the present disclosure is not limited to the embodiments described and illustrated herein, but may extend to other embodiments, as known or as would be known to those skilled in the art. Reference in the specification to "one embodiment," "the embodiment," "these embodiments," or "some embodiments" means that a particular feature, structure, or characteristic described is included in at least one embodiment, and the appearances of the phrases in various places in the specification are not necessarily all referring to the same embodiment.
Finally, although various embodiments have been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended drawings is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as example forms of implementing the claimed subject matter.
Claims (8)
1. A switching power supply with overshoot protection, comprising:
a step-down circuit including a first switch and a second switch connected in series, configured to charge or discharge an inductor by alternately turning on the first switch and the second switch to step down an input voltage to an output voltage;
an overshoot protection circuit configured to generate a compensation voltage based on a set value of the input voltage and the output voltage; and
a switch control circuit generating a switch control signal to control the first switch and the second switch to be alternately turned on based on the compensation voltage and the input voltage.
2. The switching power supply of claim 1, wherein the compensation voltage comprises a first compensation voltage and a second compensation voltage, and the first compensation voltage is higher than the second compensation voltage, wherein the overshoot protection circuit is configured to:
generating the first compensation voltage in response to the input voltage being less than or equal to a set value of the output voltage; and
generating the second compensation voltage in response to the input voltage being higher than a set value of the output voltage.
3. The switching power supply of claim 2, wherein the overshoot protection circuit comprises:
a protection voltage generation circuit configured to generate a protection voltage based on a feedback voltage associated with the output voltage, a predetermined reference voltage, and a predetermined current source; and
a compensation voltage generation circuit configured to generate the compensation voltage based on the protection voltage, the predetermined reference voltage, and the feedback voltage.
4. The switching power supply according to claim 3, wherein the protection voltage generating circuit comprises:
a comparator having one input terminal receiving a first boosted value of the feedback voltage and the other input terminal receiving the predetermined reference voltage, and generating a comparison signal based on the first boosted value and the predetermined reference voltage;
a voltage buffer boosting the feedback voltage to a second boosted voltage value upon triggering of the comparison signal; and
a third switch that is turned on under control of a third switch control signal to provide the second boosted value as the protection voltage, wherein the third switch control signal is obtained by an AND operation of the comparison signal and a control signal.
5. The switching power supply of claim 3, wherein the compensation voltage generation circuit is configured to:
in response to the protection voltage being less than the predetermined reference voltage, generating the first compensation voltage based on the protection voltage and the feedback voltage; and
in response to the protection voltage being greater than or equal to the predetermined reference voltage, generating the second compensation voltage based on the predetermined reference voltage and the feedback voltage.
6. The switching power supply of claim 1, wherein the switch control circuit comprises:
an oscillator for generating an operating clock signal and a slope compensation signal having the same frequency;
a pulse width modulation signal generator comparing the compensation voltage with a sum of the sampled signal of the input voltage and the slope compensation signal to generate a pulse width modulation signal; and
and the switch control signal generating circuit generates the switch control signal based on the working clock signal and the pulse width modulation signal.
7. The switching power supply of claim 6, wherein the switch control signal comprises a first switch control signal and a second switch control signal, and the control signal generation circuit comprises:
and a reset end of the D trigger receives the pulse width modulation signal and sets the D trigger to output the second switch control signal to turn on the second switch and turn off the first switch.
8. The switching power supply of claim 1, wherein the voltage-reduction circuit further comprises:
a voltage divider circuit configured to divide the output voltage to generate a feedback voltage associated with the output voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211073907.1A CN115378246B (en) | 2022-09-02 | 2022-09-02 | Switching power supply with overshoot protection |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211073907.1A CN115378246B (en) | 2022-09-02 | 2022-09-02 | Switching power supply with overshoot protection |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115378246A true CN115378246A (en) | 2022-11-22 |
| CN115378246B CN115378246B (en) | 2023-04-21 |
Family
ID=84070005
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211073907.1A Active CN115378246B (en) | 2022-09-02 | 2022-09-02 | Switching power supply with overshoot protection |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115378246B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103532378A (en) * | 2012-07-05 | 2014-01-22 | 晶豪科技股份有限公司 | Voltage converter capable of suppressing output voltage overshooting |
| CN104821718A (en) * | 2015-05-05 | 2015-08-05 | 南京矽力杰半导体技术有限公司 | Boost type circuit based on input voltage feedforward control and control method thereof |
| CN106300944A (en) * | 2016-08-06 | 2017-01-04 | 杰华特微电子（张家港）有限公司 | Over-current control circuit, cross method of flow control and apply its power-supply system |
| US20210099073A1 (en) * | 2019-09-27 | 2021-04-01 | Apple Inc. | Peak Voltage Overshoot Control for Switch Mode Power Converters |
-
2022
- 2022-09-02 CN CN202211073907.1A patent/CN115378246B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103532378A (en) * | 2012-07-05 | 2014-01-22 | 晶豪科技股份有限公司 | Voltage converter capable of suppressing output voltage overshooting |
| CN104821718A (en) * | 2015-05-05 | 2015-08-05 | 南京矽力杰半导体技术有限公司 | Boost type circuit based on input voltage feedforward control and control method thereof |
| CN106300944A (en) * | 2016-08-06 | 2017-01-04 | 杰华特微电子（张家港）有限公司 | Over-current control circuit, cross method of flow control and apply its power-supply system |
| US20210099073A1 (en) * | 2019-09-27 | 2021-04-01 | Apple Inc. | Peak Voltage Overshoot Control for Switch Mode Power Converters |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115378246B (en) | 2023-04-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8624566B2 (en) | Current-mode control switching regulator and operations control method thereof | |
| KR100953362B1 (en) | Current-mode controlled switching regulator and control method therefor | |
| US7940031B2 (en) | Switching power supply circuitry | |
| US9774255B2 (en) | Synchronous buck DC-DC converter and method thereof | |
| US8773090B2 (en) | Voltage regulator with adaptive hysteretic control | |
| JP5195182B2 (en) | Current mode control switching regulator | |
| KR100744592B1 (en) | Dc-dc converter, dc-dc converter control circuit, and dc-dc converter control method | |
| US20140049994A1 (en) | Device for synchronous dc-dc conversion and synchronous dc-dc converter | |
| US8866450B2 (en) | Electronic device and method for DC-DC conversion | |
| US9997123B2 (en) | Switching power supply circuit, liquid crystal driving device, and liquid crystal display device | |
| US7932709B1 (en) | Stable high efficiency step-up voltage regulator with fast transient response and ultra low output voltage ripple | |
| US10075078B2 (en) | Control circuit for maintaining a switching frequency for constant on time converter | |
| WO2020243902A1 (en) | Adaptive minimum on time control for switching regulator | |
| TW200917632A (en) | Comparator type DC-DC converter | |
| CN111869072B (en) | Control circuit of voltage conversion circuit | |
| US10447154B2 (en) | PWM control scheme for providing minimum on time | |
| US20090285003A1 (en) | Boost converter | |
| US8174249B2 (en) | Voltage boosting/lowering circuit | |
| CN115378246B (en) | Switching power supply with overshoot protection | |
| CN114400896A (en) | Integrated circuit and power supply device | |
| US7295082B2 (en) | Pulse frequency modulation oscillating circuit for a DC/DC converter | |
| JP7399739B2 (en) | switching power supply | |
| US10289136B1 (en) | Converting apparatus and method thereof | |
| CN114400895B (en) | Integrated circuit and power supply device | |
| US20220407421A1 (en) | Control circuit for dc/dc converter |
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 | ||
| CB02 | Change of applicant information |
Address after: Room 1101, 11th Floor, No. 51, Xueyuan Road, Haidian District, Beijing 100083 Applicant after: Xinzhou Technology (Beijing) Co.,Ltd. Address before: 100095 No.15, 2nd floor, building 1, yard 33, Dijin Road, Haidian District, Beijing Applicant before: SILICON CONTENT TECHNOLOGY (BEIJING) Co.,Ltd. |
|
| CB02 | Change of applicant information | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |