CN115360904A - DC/DC switching power supply control system, method, chip and electronic equipment - Google Patents

DC/DC switching power supply control system, method, chip and electronic equipment Download PDF

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Publication number
CN115360904A
CN115360904A CN202211083067.7A CN202211083067A CN115360904A CN 115360904 A CN115360904 A CN 115360904A CN 202211083067 A CN202211083067 A CN 202211083067A CN 115360904 A CN115360904 A CN 115360904A
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power supply
switching power
time
output
generator
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孔庆河
严之嶽
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Shanghai Awinic Technology Co Ltd
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Shanghai Awinic Technology Co Ltd
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    • 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
    • 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
    • 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
    • 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
    • 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
    • H02M3/1582—Buck-boost converters

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The application discloses a control system, a control method, a control chip and electronic equipment of a DC/DC switching power supply, which can keep the switching frequency of the DC/DC switching power supply constant under the condition of input and output voltage fluctuation. The DC/DC switching power supply control system includes: a duty cycle signal generator and an adaptive off-time generator; the duty ratio signal generator is used for generating a duty ratio signal D of the DC/DC switching power supply; the self-adaptive turn-off time generator is used for sampling the input and output voltages of the DC/DC switching power supply in real time; when any one parameter in the input and output voltages changes, the output voltage is adjusted according to the change of the parameterThe change of the parameter dynamically adjusts the off-time T in the duty cycle signal D OFF To maintain the switching frequency of the DC/DC switching power supply constant.

Description

DC/DC switching power supply control system, method, chip and electronic equipment
Technical Field
The invention relates to the technical field of switching power supplies, in particular to a DC/DC switching power supply control system, a method, a chip and electronic equipment.
Background
The DC/DC switching power supply realizes the regulation and control of the output voltage by controlling the duty ratio of the switching tube. One of the existing control modes is a fixed off-time control mode (the off-time will not change after the circuit parameters of the DC/DC switching power supply are determined), but the problem that the switching frequency fluctuates with the input and output voltages exists in the control mode. In the following, the DC/DC switching power supply is exemplified as a Buck-Boost switching power supply:
the volt-second method shows that the corresponding relationship between the switching period and the turn-off time of the Buck-Boost switching power supply is as follows:
Figure BDA0003834229750000011
where D is the duty cycle, T is the inverse of the switching period, i.e., the switching frequency, VIN is the input voltage, VOUT is the output voltage, and T is the duty cycle OFF The off time.
When the switch is turned off, the time T is shown in the formula (1) OFF At a fixed value, the switching frequency may vary with the fluctuation of the input voltage VIN and the output voltage VOUT, and the switching frequency cannot be constant.
Disclosure of Invention
In view of the above, the present invention provides a DC/DC switching power supply control system, method, chip and electronic device to achieve that the switching frequency of the DC/DC switching power supply remains constant even if the input and output voltages fluctuate.
A DC/DC switching power supply control system comprising: a duty cycle signal generator and an adaptive off-time generator;
the duty ratio signal generator is used for generating a duty ratio signal D of the DC/DC switching power supply;
the self-adaptive turn-off time generator is used for sampling the input and output voltages of the DC/DC switching power supply in real time; when any parameter in the input and output voltages changes, the off time T in the duty ratio signal D is dynamically adjusted along with the change of the parameter OFF To maintain the switching frequency of the DC/DC switching power supply constant.
Optionally, when the DC/DC switching power supply is a Buck-Boost switching power supply, the adaptive turn-off time generator turns off the switching power supply by enabling the turn-off time T OFF And with
Figure BDA0003834229750000021
Inversely proportional to maintain the switching frequency of the DC/DC switching power supply constant;
wherein VIN represents the DC/DC switching power supply input voltage, and VOUT represents the DC/DC switching power supply output voltage.
Optionally, the adaptive off-time generator includes: a turn-off time generating current source, a turn-off time generating voltage source and a turn-off time generating circuit;
the turn-off time generation current source is a current source with output current of a preset value ItOFF;
the off-time generating voltage source comprises: a controllable switch S1 and a capacitor CtOFF; the positive pole of the capacitor CtOFF is connected with the output end of the current source generated by the turn-off time, and the negative pole of the capacitor CtOFF is grounded; the controllable switch S1 is connected in parallel to the capacitor CtOFF; the controllable switch S1 is switched on under the drive of a high level and switched off under the drive of a low level; the OR gate O1 outputs a low level period as a corrected turn-off time T OFF ；
The off-time generating circuit includes: a first PWM comparator U3 and an or gate O1; one input end of the first PWM comparator U3 is connected with the anode of the capacitor CtOFF, and the other input end of the first PWM comparator U3 receives a reference voltage Vref; the output end of the first PWM comparator U3 is connected with one input end of the OR gate O1; the other input end of the OR gate O1 receives the duty ratio signal D; the output end of the OR gate O1 is simultaneously connected with the duty ratio signal generator and the control end of the controllable switch S1;
the value requirements of the preset value ItOFF and the reference voltage Vref are as follows: off time T OFF The switching frequency of the DC/DC switching power supply is constant along with the variation of the input and output voltages of the DC/DC switching power supply.
Optionally, the reference voltage Vref and the current ItOFF are respectively:
Figure BDA0003834229750000022
ItOFF＝I1+I2，
in the formula (I), the compound is shown in the specification,
Figure BDA0003834229750000031
K IN r and k are constants, k +1=K IN 。
Optionally, the off-time generating current source includes: a proportional current source and a mirror current source; the reference current of the proportional current source is
Figure BDA0003834229750000032
The ratio of the reference current to the output current of the proportional current source is 1:k; the reference current of the mirror current source is
Figure BDA0003834229750000033
And the output ends of the proportional current source and the mirror current source are connected together to be used as the output end of the turn-off time generation current source.
Optionally, the proportional current source includes: the device comprises a first PMOS tube P1, a second PMOS tube P2, a first resistor R1, a first error amplifier U1 and a first NMOS tube N1;
wherein the non-inverting input terminal of the first error amplifier U1 receives the reference voltage
Figure BDA0003834229750000034
The output end of the first error amplifier U1 is connected with the grid electrode of the first NMOS tube N1;
the collector of the first NMOS tube N1 is connected with the inverting input end of the first error amplifier U1 and is grounded through a first resistor R1;
the drain of the first NMOS transistor N1 is simultaneously connected to the drain of the first PMOS transistor P1, the grid of the first PMOS transistor P1 and the grid of the second PMOS transistor P2;
the source electrode of the first PMOS pipe P1 is connected with the source electrode of the second PMOS pipe P2;
the drain of the second PMOS pipe P2 is the output end of the proportional current source;
the resistance value of the first resistor R1 is R.
Optionally, the mirror current source includes: a third PMOS tube P3, a fourth PMOS tube P4, a second resistor R2, a second error amplifier U2 and a second NMOS tube N2;
the non-inverting input terminal of the second error amplifier U2 receives the reference voltage
Figure BDA0003834229750000035
The inverting input end of the second error amplifier U2 is connected with the source electrode of the second NMOS tube N2 and is grounded through a second resistor R2; the output end of the second error amplifier U2 is connected with the grid electrode of the second NMOS tube N2; the drain electrode of the second NMOS tube N2 is simultaneously connected to the drain electrode of the fourth PMOS tube P4, the grid electrode of the third PMOS tube P3 and the grid electrode of the fourth PMOS tube P4;
the source electrode of the third PMOS pipe P3 is connected with the source electrode of the fourth PMOS pipe P4;
the drain of the third PMOS tube P3 is the output end of the mirror current source;
the resistance value of the second resistor R2 is R.
Optionally, when the DC/DC switching power supply is a Buck-Boost switching power supply, the duty ratio signal generator includes: the feedback circuit comprises a feedback network, a third error amplifier, a second PWM comparator, a first RS trigger and a current sampling circuit;
the feedback network samples the output voltage VOUT of the DC/DC switching power supply and feeds the output voltage VOUT back to the non-inverting input end of the third error amplifier; the inverting input end of the third error amplifier receives a reference voltage VREF; the output end of the third error amplifier is connected to the inverting input end of the second PWM comparator;
the current sampling circuit samples the current of the power stage of the Buck-Boost switching power supply and feeds the current back to the non-inverting input end of the second PWM comparator; the output end of the second PWM comparator is connected to the R end of the first RS trigger; the Q end of the first RS trigger is used for sending a duty ratio signal D to the self-adaptive turn-off time generator and the power stage, and the self-adaptive turn-off time generator is used for sending a turn-off time adjusting signal D to the S end of the first RS trigger OFF 。
Optionally, the DC/DC switching power supply control system further includes: a minimum on-time generator;
the minimum on-time generator is used for enabling the output of the self-adaptive off-time generator to be output to the duty ratio signal generator after a certain delay time within the overshoot time of the output voltage VOUT of the DC/DC switching power supply.
Optionally, when the DC/DC switching power supply is a Buck-Boost switching power supply, the duty ratio signal generator includes: the feedback circuit comprises a feedback network, a third error amplifier, a second PWM comparator, a first RS trigger and a current sampling circuit;
the feedback network samples the output voltage VOUT of the DC/DC switching power supply and feeds the output voltage VOUT back to the non-inverting input end of the third error amplifier; the inverting input end of the third error amplifier receives a reference voltage VREF; the output end of the third error amplifier is connected to the inverting input end of the second PWM comparator;
the current sampling circuit samples the current of the power stage of the Buck-Boost switching power supply and feeds the current back to the non-inverting input end of the second PWM comparator; the output end of the second PWM comparator is connected to the R end of the first RS trigger; the Q end of the first RS trigger is used for sending a duty ratio signal D to the self-adaptive turn-off time generator and the power stage, and the self-adaptive turn-off time generator is used for sending a turn-off time adjusting signal D to the S end of the first RS trigger OFF ；
The input end of the minimum on-time generator is connected with the output end of the second PWM comparator and the output end of the self-adaptive off-time generator, and the output end of the minimum on-time generator is connected with the R end of the first RS trigger.
A DC/DC switching power supply control method includes:
generating a duty ratio signal D of the DC/DC switching power supply;
sampling the input and output voltages of the DC/DC switching power supply in real time; when any parameter in the input and output voltages changes, the off time T in the duty ratio signal D is dynamically adjusted along with the change of the parameter OFF To maintain the switching frequency of the DC/DC switching power supply constant.
OptionallyWhen any one parameter in the input and output voltages changes, the off time T in the duty ratio signal D is dynamically adjusted along with the change of the parameter OFF To maintain a constant switching frequency of the DC/DC switching power supply, comprising:
adjusting the charging time of the capacitor CtOFF, comprising: acquiring voltage at two ends of a capacitor CtOFF, when the voltage at the two ends of the capacitor CtOFF is reduced to be lower than reference voltage Vref, controlling the capacitor CtOFF to discharge when an original duty ratio signal D of the DC/DC switching power supply is at a high level, controlling the capacitor CtOFF to charge when the original duty ratio signal D is at a low level, and controlling the charging current to be a preset value ItOFF; controlling the capacitor CtOFF to discharge when the voltage at two ends of the capacitor CtOFF exceeds the reference voltage Vref;
taking the charging time of the capacitor CtOFF as the corrected turn-off time T OFF ；
The value requirements of the preset value ItOFF and the reference voltage Vref are as follows: off time T OFF The switching frequency of the DC/DC switching power supply is constant along with the variation of the input and output voltages of the DC/DC switching power supply.
Optionally, during the overshoot time of the output voltage VOUT of the DC/DC switching power supply, the off-time T of the duty ratio signal D is dynamically adjusted according to the change of the parameter OFF And replacing with:
dynamically delay adjusting the off-time T in the duty cycle signal D as the parameter changes OFF 。
A DC/DC switching power supply chip comprising: the power stage and the control system of the DC/DC switching power supply are arranged on the substrate; the control system is any one of the DC/DC switching power supply control systems disclosed above.
An electronic device, comprising: any of the DC/DC switching power supply control systems disclosed above.
It can be seen from the above technical solutions that, in the present invention, an adaptive off-time generator is added on the basis of a duty ratio signal D generated in a fixed off-time control manner, and when any parameter of input and output voltages of a DC/DC switching power supply changes, the adaptive off-time generator samples the parameter change and follows the parameter changeDynamically adjusting the turn-off time T OFF So as to counteract the switching frequency variation caused by the parameter variation, thereby maintaining the switching frequency constant.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a DC/DC switching power supply control system according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of an adaptive turn-off time generator according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of an embodiment of the adaptive off-time generator shown in FIG. 2;
fig. 4 is a schematic structural diagram of a Buck-Boost switching power supply control system disclosed in the embodiment of the invention;
fig. 5 is a schematic structural diagram of another Buck-Boost switching power supply control system disclosed in the embodiment of the invention;
fig. 6 is a timing diagram of the output signals D of the adaptive off-time generator 20, the second PWM comparator 103, and the first RS flip-flop 104 before the minimum on-time generator 107 is introduced;
fig. 7 is a timing diagram of the output signals D of the adaptive off-time generator 20, the second PWM comparator 103, the minimum on-time generator 107, and the first RS flip-flop 104 after the minimum on-time generator 107 is introduced;
fig. 8 is a flowchart of a DC/DC switching power supply control method 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.
Referring to fig. 1, an embodiment of the present invention discloses a DC/DC switching power supply control system, including: a duty cycle signal generator 10 and an adaptive off-time generator 20;
the duty ratio signal generator 10 is configured to generate a duty ratio signal D of the DC/DC switching power supply; specifically, the duty cycle signal generator 10 is configured to generate a duty cycle signal D of the DC/DC switching power supply according to the input/output voltage of the DC/DC switching power supply and the inductor voltage signal SW, so as to regulate and control the output voltage VOUT of the DC/DC switching power supply;
an adaptive off-time generator 20 for sampling the input and output voltages of the DC/DC switching power supply in real time; when any parameter in the input and output voltages changes, the turn-off time in the duty ratio signal D, namely the turn-off time T of the DC/DC switching power supply, is dynamically adjusted along with the change of the parameter OFF (i.e., the adaptive off-time generator 20 sends an off-time adjustment signal D to the duty signal generator 10 OFF ) To maintain the switching frequency of the DC/DC switching power supply constant.
The working principle of the solution shown in fig. 1 is as follows: for a DC/DC switching power supply, the output voltage VOUT can be regulated and controlled by controlling the duty ratio of a switching tube, but the turn-off time T is short OFF The switching frequency fluctuates with the input and output voltage when the switching frequency is constant, so the scheme shown in fig. 1 does not make the duty cycle signal generator 10 generate the duty cycle signal D in a fixed off-time control manner any more, but adds an adaptive off-time generator 20 on the basis of the duty cycle signal generator 10. When any parameter in the input and output voltages of the DC/DC switching power supply changes, the adaptive turn-off time generator 20 samples the parameter change and dynamically adjusts the turn-off time T according to the parameter change OFF So as to counteract the switching frequency variation caused by the parameter variation, thereby maintaining the switching frequency constant.
The DC/DC switching power supply may be a Buck-Boost switching power supply, a Buck switching power supply, or a Boost switching power supply, but is not limited thereto. The following still takes a Buck-Boost switching power supply as an example to illustrate the above working principle:
the formula (1) given in the "background" section of this specification can be modified as follows:
Figure BDA0003834229750000071
as can be seen from equation (2), as long as the off-time T is designed OFF And with
Figure BDA0003834229750000072
The Buck-Boost switching power supply is inversely proportional, and the switching frequency (namely 1/T) of the Buck-Boost switching power supply can be constant. The product of the two inversely proportional quantities is a constant, called the scaling factor, whose inverse is the magnitude of the switching frequency of the Buck-Boost switching power supply.
Based on this, the embodiment of the present invention does not let the off time T any more OFF Is a fixed value, but the off-time T is realized by designing an adaptive off-time generator 20 OFF Adaptive adjustment of (2). When any one of the input voltage VIN and the output voltage VOUT of the Buck-Boost switching power supply changes, the adaptive turn-off time generator 20 samples the change of the parameter and dynamically adjusts the turn-off time T of the Buck-Boost switching power supply accordingly OFF So that the turn-off time T OFF And with
Figure BDA0003834229750000081
And the proportion is inverse, so that the switching frequency change caused by the parameter change is counteracted, and the switching frequency of the Buck-Boost switching power supply is kept constant.
Optionally, based on any of the embodiments disclosed above, referring to fig. 2, the adaptive off-time generator 20 includes: an off-time generating current source 110, an off-time generating voltage source 111, and an off-time generating circuit 112;
the turn-off time generating current source 110 is a current source with an output current of a preset value ItOFF;
the off-time generating voltage source 111 includes: a controllable switch S1 and a capacitor CtOFF; the positive pole of the capacitor CtOFF is connected with the output end of the off-time generation current source 110, and the negative pole of the capacitor CtOFF is grounded; the controllable switch S1 is connected in parallel to the capacitor CtOFF; the controllable switch S1 is closed under the drive of a high level and is closed under the drive of a low level;
the off-time generation circuit 112 includes: a first PWM comparator U3 and an or gate O1; one input end of the first PWM comparator U3 is connected with the anode of the capacitor CtOFF, and the other input end of the first PWM comparator U3 receives a reference voltage Vref; the output end of the first PWM comparator U3 is connected with one input end of the OR gate O1; the other input end of the OR gate O1 receives the duty ratio signal D; the output end of the or gate O1 is connected to the duty ratio signal generator 10 and the control end of the controllable switch S1 at the same time, that is, the or gate O1 outputs the off-time adjusting signal D OFF And multiplexed as a switch control signal of the controllable switch S1; the OR gate O1 outputs a low level period as a corrected turn-off time T OFF ；
The value requirements of the preset value ItOFF and the reference voltage Vref are as follows: off time T OFF The switching frequency of the DC/DC switching power supply is constant along with the variation of the input and output voltages of the DC/DC switching power supply.
Still taking the Buck-Boost switching power supply as an example, the value requirement is as follows: off time T OFF And
Figure BDA0003834229750000082
in inverse proportion. For example, the reference voltage Vref and the current ItOFF may be set to:
Figure BDA0003834229750000083
itoff = I1+ I2 formula (4)
In the formula (I), the compound is shown in the specification,
Figure BDA0003834229750000091
K IN r and k are constants, k +1=K IN 。
Formula (2) andthe values of ItOFF and Vref set in equation (3) enable the off-time T OFF And
Figure BDA0003834229750000092
in inverse proportion, the analysis is as follows:
taking the example that the inverting input terminal of the first PWM comparator U3 receives the reference voltage Vref, when the controllable switch S1 is closed, the capacitor CtOFF is discharged to the ground through the controllable switch S1, and the voltage at the non-inverting input terminal of the first PWM comparator U3 gradually decreases to the reference voltage of the first PWM comparator U3
Figure BDA0003834229750000093
Then, at this time, the first PWM comparator U3 outputs a low level, and the or gate O1 outputs the original duty ratio signal D of the DC/DC switching power supply; when S1 is disconnected, the current ItOFF charges the capacitor CtOFF, and the voltage at the non-inverting input end of the first PWM comparator U3 gradually rises and exceeds the reference voltage of the first PWM comparator U3 along with the accumulation of the charging time
Figure BDA0003834229750000094
At this time, the first PWM comparator U3 outputs a high level, and the or gate O1 outputs a high level. The on-off of S1 is controlled by the output signal of the OR gate O1, S1 is closed when the OR gate O1 outputs high level and is opened when the OR gate O1 outputs low level, and the period of the OR gate O1 outputting low level is used as the corrected off time T OFF At this time, the internal capacitance CtOFF is charged; making the OR gate O1 output a high level period as a corrected opening time T ON The capacitor CtOFF discharges during this time.
Due to the off-time T after correction OFF In this case, the capacitance CtOFF is charged to the reference voltage with the current ItOFF
Figure BDA0003834229750000095
Then, according to coulomb's law, the electric quantity Q of the available capacitance CtOFF satisfies:
Figure BDA0003834229750000096
by combining formulae (4) to (5), the compounds are obtained
Figure BDA0003834229750000097
By combining formula (2) and formula (6), the compounds are obtained
Figure BDA0003834229750000098
Let (K + 1) = K IN N is then
Figure BDA0003834229750000101
As shown in the formula (8), k +1=K IN The switching period T can be set to a constant value even if the switching frequency of the DC/DC switching power supply is set to a constant value. In practical applications, the value of the switching period T may be defined by setting the magnitudes of n, R, ctOFF in advance, for example, n =3, R =3M Ω, ctOFF =1pF, and corresponding T =1us may be set.
Alternatively, when the value of ItOFF is as shown in equation (4), as shown in fig. 3, the off-time generating current source 110 includes: a proportional current source 1 and a mirror current source 2; the reference current of the proportional current source 1 is
Figure BDA0003834229750000102
The ratio of the reference current to the output current of the proportional current source 1 is 1:k; the reference current of the mirror current source 2 is
Figure BDA0003834229750000103
The output terminals of the proportional current source 1 and the mirror current source 2 are connected together as the output terminal of the off-time generating current source 110.
Alternatively, still referring to fig. 3, the proportional current source 1 may adopt the following topology:
the proportional current source 1 includes: the device comprises a first PMOS tube P1, a second PMOS tube P2, a first resistor R1, a first error amplifier U1 and a first NMOS tube N1;
wherein the non-inverting input terminal of the first error amplifier U1 receives the reference voltage
Figure BDA0003834229750000104
The output end of the first error amplifier U1 is connected with the grid electrode of the first NMOS tube N1;
the collector electrode of the first NMOS tube N1 is connected with the inverting input end of the first error amplifier U1 and is grounded through a first resistor R1;
the drain of the first NMOS transistor N1 is simultaneously connected to the drain of the first PMOS transistor P1, the grid of the first PMOS transistor P1 and the grid of the second PMOS transistor P2;
the source electrode of the first PMOS pipe P1 is connected with the source electrode of the second PMOS pipe P2;
the drain of the second PMOS pipe P2 is the output end of the proportional current source 1;
the resistance value of the first resistor R1 is R.
The operation principle of the proportional current source 1 having the above topology is as follows:
because the source voltage of the first NMOS tube N1 is fed back to the inverting input end of the first error amplifier U1, deep negative feedback is formed, and circuit analysis can be carried out by utilizing the 'virtual short' characteristic of the error amplifier. The term "virtual short" means that the voltages at the non-inverting input and the inverting input of the error amplifier are equal. Under the deep negative feedback, the source voltage of the first NMOS transistor N1 is equal to the reference voltage
Figure BDA0003834229750000111
The first resistor R1, the first NMOS transistor N1 and the first PMOS transistor P1 are connected in series on the same branch, and the current of the branch is equal to that of the branch
Figure BDA0003834229750000112
The first PMOS transistor P1 and the second PMOS transistor P2 jointly form a core part of the proportional current source 1, and the current flowing through the first PMOS transistor P1 and the current flowing through the second PMOS transistor P2 are in a fixed proportion of 1:k.
Alternatively, still referring to fig. 3, the mirror current source 2 may employ the following topology:
the mirror current source 2 includes: a third PMOS tube P3, a fourth PMOS tube P4, a second resistor R2, a second error amplifier U2 and a second NMOS tube N2;
the non-inverting input terminal of the second error amplifier U2 receives the reference voltage
Figure BDA0003834229750000113
The inverting input end of the second error amplifier U2 is connected with the source electrode of the second NMOS tube N2 and is grounded through a second resistor R2; the output end of the second error amplifier U2 is connected with the grid electrode of the second NMOS tube N2; the drain electrode of the second NMOS tube N2 is simultaneously connected to the drain electrode of the fourth PMOS tube P4, the grid electrode of the third PMOS tube P3 and the grid electrode of the fourth PMOS tube P4;
the source electrode of the third PMOS pipe P3 is connected with the source electrode of the fourth PMOS pipe P4;
the drain of the third PMOS tube P3 is the output end of the mirror current source 2;
the resistance value of the second resistor R2 is R.
The mirror current source 2 with the above topology operates as follows:
because the source voltage of the second NMOS tube N2 is fed back to the inverting input end of the second error amplifier U2, the deep negative feedback is formed, and the 'virtual short' characteristic of the error amplifier can be used for circuit analysis. Under the condition of the depth negative feedback, the source voltage of the second NMOS tube N2 is equal to the reference voltage
Figure BDA0003834229750000114
The second resistor R2, the second NMOS transistor N2 and the fourth PMOS transistor P4 are connected in series on the same branch circuit, and the current of the branch circuit is equal to that of the branch circuit
Figure BDA0003834229750000115
The third PMOS transistor P3 and the fourth PMOS transistor P4 together form a core portion of the mirror current source 2, and a current flowing through the third PMOS transistor P3 and a current flowing through the fourth PMOS transistor P4 are 1:1 in a fixed ratio.
Optionally, reference voltage
Figure BDA0003834229750000121
Can be obtained by a voltage division circuit, and specifically comprises the following steps: a third resistor R3 and a fourth resistor R4 are connected in series between the input voltage VIN and the ground in sequence, and the ratio of the resistance values of the third resistor R3 to the fourth resistor R4 is (K) IN -1) the junction of 1, the third resistor R3 and the fourth resistor R4 outputs a reference voltage
Figure BDA0003834229750000122
Optionally, in any of the embodiments disclosed above that employ the controllable switch S1, the controllable switch S1 may employ, for example, an IGBT or a triode, but is not limited thereto.
In any of the Buck-Boost switching power supply embodiments disclosed above, the duty cycle signal generator 10 may adopt a structure as shown in fig. 4. The specific description is as follows:
the power stage 100 of the Buck-Boost switching power supply comprises a third N-type switching tube N3, a diode and an inductor L1; the electric energy input end of the third N-type switching tube N3 receives an input voltage VIN; the electric energy output end of the third N-type switching tube N3 is grounded through the inductor L1 and is connected with the cathode of the diode, and the anode of the diode outputs voltage VOUT. The third N-type switch tube N3 may be an IGBT, an NMOS tube, or a triode, but is not limited thereto.
The duty signal generator 10 includes: a feedback network 101, a third error amplifier 102, a second PWM comparator 103, a first RS flip-flop 104 and a current sampling circuit 108;
the feedback network 101 samples the output voltage VOUT and feeds back the output voltage VOUT to a non-inverting input terminal of the third error amplifier 102; the inverting input terminal of the third error amplifier 102 receives the reference voltage VREF; the output end of the third error amplifier 102 is connected to the inverting input end of the second PWM comparator 103;
the current sampling circuit 108 samples the current of the power stage 100 and feeds the current back to the non-inverting input terminal of the second PWM comparator 103; the output end of the second PWM comparator 103 is connected to the R end of the first RS flip-flop 104; the Q terminal of the first RS flip-flop 104 is used for sending the duty ratio signal D to the adaptive off-time generator 20 and the power stage 100, and the adaptive off-time generator 20 is used for triggering the first RS flip-flopThe S terminal of the device 104 sends an off-time adjustment signal D OFF 。
The working principle of fig. 4 is as follows:
the feedback network 101 generates a feedback voltage FB, which is connected to the non-inverting input terminal of the third error amplifier 102, the inverting input terminal of the third error amplifier 102 is a reference voltage VREF, and the output signal of the third error amplifier 102 and the output signal of the current sampling circuit 108 are respectively connected to the inverting input terminal and the non-inverting input terminal of the second PWM comparator 103; the output signal of the second PWM comparator 103 is connected to the R terminal of the first RS flip-flop 104, and determines the on-time D × T of the switching tube N3 in the power stage 100; the adaptive off-time generator 20 is connected to the S terminal of the first RS flip-flop 106, and determines the off-time (1-D) × T of the freewheeling transistor N3 in the power stage 100.
When the peak inductor current (converted into a voltage signal inside the circuit) sampled by the current sampling circuit 108 exceeds the output voltage of the third error amplifier 102, the output of the second PWM comparator 103 is high, the output signal D of the first RS flip-flop 104 is low, the switch tube N3 is turned off, the adaptive off-time generator 20 starts timing, and the off-time T is counted OFF Then, the switch tube N3 is turned on again, the inductive current continues to rise, and is turned off after reaching the peak value, and the turn-off time T is counted OFF And then opened again until the system reaches a steady state, i.e. the output voltage is equal to the set value.
Optionally, a diode in the power stage 100 of the Buck-Boost switching power supply may also be replaced by a fourth N-type switching tube N4, as shown in fig. 5: the electric energy input end of the third N-type switching tube N3 receives an input voltage VIN; the electric energy output end of the third N-type switching tube N3 is grounded through the inductor L1 and is simultaneously connected with the electric energy input end of the fourth N-type switching tube N4, and the electric energy output end of the fourth N-type switching tube N4 outputs voltage VOUT. The third N-type switching tube N3 and the fourth N-type switching tube N4 may be IGBTs, NMOS tubes, or triodes, but are not limited thereto. The on-time of the fourth N-type switch tube N4 is (1-D) × T.
Optionally, a minimum on-time generator 107 is further introduced in fig. 4 and 5, taking fig. 5 as an example: an input end of the minimum on-time generator 107 is connected with an output end of the second PWM comparator 103 and an output end of the adaptive off-time generator 20, and an output end of the minimum on-time generator 107 is connected with an R end of the first RS flip-flop 104. The principle is as follows: when the output voltage VOUT continues to be high (overshoot at the time of load or supply voltage regulation), the output of the third error amplifier 102 continues to be low, and the output of the second PWM comparator 103 continues to be high, if there is no minimum on-time generator 107, the duty ratio signal D continues to be low before the overshoot ends, the switching tube N3 remains off, VOUT requires a long regulation process, and the voltage may overshoot; in order to solve the problem, a minimum on-time generator 107 is introduced, the output of the minimum on-time generator 107 is a signal generated after the output of the adaptive off-time generator 20 is delayed for a certain delay time, the delay time (minimum on-time) is generally set to be between 50ns and 200ns, in the above case, each period of the switch is kept to work according to the minimum on-time, the VOUT regulation time is shorter, and no overshoot occurs. Corresponding timing diagrams are seen in fig. 6 and 7; the timing of the output signal D of the adaptive off-time generator 20, the second PWM comparator 103, the first RS flip-flop 104 before the introduction of the minimum on-time generator 107 is shown in fig. 6; fig. 7 shows the timing of the output signal D of the adaptive off-time generator 20, the second PWM comparator 103, the minimum on-time generator 107, and the first RS flip-flop 104 after the minimum on-time generator 107 is introduced.
It should be noted that the minimum on-time generator is not limited to be applied to the Buck-Boost switching power supply, and is applicable to all DC/DC switching power supplies. And the minimum on-time generator is used for enabling the output of the self-adaptive off-time generator to be output to the duty ratio signal generator after a certain delay time when the output voltage VOUT overshoots in the overshoot time of the output voltage VOUT of the DC/DC switching power supply.
Corresponding to the above control system embodiment, the embodiment of the present invention further discloses a DC/DC switching power supply control method, as shown in fig. 8, including:
step S01: generating a duty ratio signal D of the DC/DC switching power supply;
step S02: sampling the input and output voltages of the DC/DC switching power supply in real time; when it is at homeWhen any parameter in the input and output voltages changes, the off time T in the duty ratio signal D is dynamically adjusted along with the change of the parameter OFF To maintain the switching frequency of the DC/DC switching power supply constant.
Optionally, when any one of the parameters of the input and output voltages changes, the off-time T in the duty ratio signal D is dynamically adjusted according to the change of the parameter OFF To maintain a constant switching frequency of the DC/DC switching power supply, comprising:
adjusting the charging time of the capacitor CtOFF, comprising: acquiring voltage at two ends of a capacitor CtOFF, when the voltage at the two ends of the capacitor CtOFF is reduced to be lower than reference voltage Vref, controlling the capacitor CtOFF to discharge when an original duty ratio signal D of the DC/DC switching power supply is at a high level, controlling the capacitor CtOFF to charge when the original duty ratio signal D is at a low level, and controlling the charging current to be a preset value ItOFF; controlling the capacitor CtOFF to discharge when the voltage at two ends of the capacitor CtOFF exceeds the reference voltage Vref;
taking the charging time of the capacitor CtOFF as the corrected turn-off time T OFF ；
The value requirements of the preset value ItOFF and the reference voltage Vref are as follows: off time T OFF The switching frequency of the DC/DC switching power supply is constant along with the change of the input and output voltage of the DC/DC switching power supply.
Optionally, in any of the above-disclosed DC/DC switching power supply control methods, during the overshoot time of the output voltage VOUT of the DC/DC switching power supply, the off-time T in the duty ratio signal D is dynamically adjusted according to the change of the parameter OFF And replacing with: dynamically delay adjusting the off-time T in the duty cycle signal D as the parameter changes OFF 。
In addition, the embodiment of the invention also discloses a DC/DC switching power supply chip, which comprises: the power stage and the control system of the DC/DC switching power supply are arranged on the substrate; the control system is any one of the DC/DC switching power supply control systems disclosed above.
In addition, the embodiment of the invention also discloses electronic equipment which comprises any one of the DC/DC switching power supply control systems disclosed above.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The method, the chip and the electronic device disclosed by the embodiment correspond to the control system disclosed by the embodiment, so that the description is relatively simple, and the relevant points can be referred to the part of the control system for description.
The terms "first," "second," and the like in the description and in the claims, and in the drawings, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising" does not exclude the presence of other identical elements in the process, method, article, or apparatus that comprises the element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the embodiments. Thus, the present embodiments are not intended to be limited to the embodiments shown herein but are to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (15)

1. A DC/DC switching power supply control system, comprising: a duty cycle signal generator and an adaptive off-time generator;
the duty ratio signal generator is used for generating a duty ratio signal D of the DC/DC switching power supply;
the self-adaptive turn-off time generator is used for sampling the input and output voltages of the DC/DC switching power supply in real time; when any parameter in the input and output voltages changes, the off time T in the duty ratio signal D is dynamically adjusted along with the change of the parameter OFF To maintain the switching frequency of the DC/DC switching power supply constant.
2. The DC/DC switching power supply control system according to claim 1, wherein the adaptive off-time generator controls the off-time T by making the off-time T be equal to the off-time T when the DC/DC switching power supply is a Buck-Boost switching power supply OFF And
Figure FDA0003834229740000011
inversely proportional to maintain the switching frequency of the DC/DC switching power supply constant;
where VIN represents the DC/DC switching power supply input voltage and VOUT represents the DC/DC switching power supply output voltage.
3. The DC/DC switching power supply control system according to claim 1 or 2, wherein the adaptive off-time generator comprises: a turn-off time generating current source, a turn-off time generating voltage source and a turn-off time generating circuit;
the turn-off time generation current source is a current source with output current of a preset value ItOFF;
the off-time generating voltage source comprises: a controllable switch S1 and a capacitor CtOFF; the positive pole of the capacitor CtOFF is connected with the output end of the current source generated by the turn-off time, and the negative pole of the capacitor CtOFF is grounded; the controllable switch S1 is connected in parallel to the capacitor CtOFF; the controllable switch S1 is switched on under the drive of a high level and switched off under the drive of a low level; the low level period of the output of the OR gate O1 is taken as the corrected turn-off time T OFF ；
The off-time generation circuit includes: a first PWM comparator U3 and an or gate O1; one input end of the first PWM comparator U3 is connected with the anode of the capacitor CtOFF, and the other input end of the first PWM comparator U3 receives a reference voltage Vref; the output end of the first PWM comparator U3 is connected with one input end of the OR gate O1; the other input end of the OR gate O1 receives the duty ratio signal D; the output end of the OR gate O1 is simultaneously connected with the duty ratio signal generator and the control end of the controllable switch S1;
the value requirements of the preset value ItOFF and the reference voltage Vref are as follows: off time T OFF The switching frequency of the DC/DC switching power supply is constant along with the variation of the input and output voltages of the DC/DC switching power supply.
4. The DC/DC switching power supply control system according to claim 3, wherein the reference voltage Vref and the current ItOFF are respectively:
Figure FDA0003834229740000021
ItOFF＝I1+I2，
in the formula (I), the compound is shown in the specification,
Figure FDA0003834229740000022
K IN r and k are constants, k +1=K IN 。
5. The DC/DC switching power supply control system according to claim 4, wherein the off-time generating current source comprises: a proportional current source and a mirror current source; the reference current of the proportional current source is
Figure FDA0003834229740000023
The ratio of the reference current to the output current of the proportional current source is 1:k; the reference current of the mirror current source is
Figure FDA0003834229740000024
And the output ends of the proportional current source and the mirror current source are connected together to be used as the output end of the turn-off time generation current source.
6. The DC/DC switching power supply control system according to claim 5, wherein the proportional current source comprises: the device comprises a first PMOS tube P1, a second PMOS tube P2, a first resistor R1, a first error amplifier U1 and a first NMOS tube N1;
wherein the non-inverting input terminal of the first error amplifier U1 receives the reference voltage
Figure FDA0003834229740000025
The output end of the first error amplifier U1 is connected with the grid electrode of the first NMOS tube N1;
the collector electrode of the first NMOS tube N1 is connected with the inverting input end of the first error amplifier U1 and is grounded through a first resistor R1;
the drain of the first NMOS transistor N1 is simultaneously connected to the drain of the first PMOS transistor P1, the grid of the first PMOS transistor P1 and the grid of the second PMOS transistor P2;
the source electrode of the first PMOS pipe P1 is connected with the source electrode of the second PMOS pipe P2;
the drain of the second PMOS tube P2 is the output end of the proportional current source;
the resistance value of the first resistor R1 is R.
7. The DC/DC switching power supply control system according to claim 5 or 6, wherein the mirror current source comprises: a third PMOS tube P3, a fourth PMOS tube P4, a second resistor R2, a second error amplifier U2 and a second NMOS tube N2;
the non-inverting input terminal of the second error amplifier U2 receives the reference voltage
Figure FDA0003834229740000031
The inverting input end of the second error amplifier U2 is connected with the source electrode of the second NMOS tube N2 and is grounded through a second resistor R2; the output end of the second error amplifier U2 is connected with the grid electrode of the second NMOS tube N2; the drain electrode of the second NMOS tube N2 is simultaneously connected to the drain electrode of the fourth PMOS tube P4, the grid electrode of the third PMOS tube P3 and the grid electrode of the fourth PMOS tube P4;
the source electrode of the third PMOS pipe P3 is connected with the source electrode of the fourth PMOS pipe P4;
the drain of the third PMOS pipe P3 is the output end of the mirror current source;
the resistance value of the second resistor R2 is R.
8. The DC/DC switching power supply control system according to claim 1 or 2, wherein when the DC/DC switching power supply is a Buck-Boost switching power supply, the duty signal generator includes: the feedback circuit comprises a feedback network, a third error amplifier, a second PWM comparator, a first RS trigger and a current sampling circuit;
the feedback network samples the output voltage VOUT of the DC/DC switching power supply and feeds the output voltage VOUT back to the non-inverting input end of the third error amplifier; the inverting input end of the third error amplifier receives a reference voltage VREF; the output end of the third error amplifier is connected to the inverting input end of the second PWM comparator;
the current sampling circuit samples the current of the power stage of the Buck-Boost switching power supply and feeds the current back to the non-inverting input end of the second PWM comparator; the output end of the second PWM comparator is connected to the R end of the first RS trigger; the Q end of the first RS trigger is used for sending a duty ratio signal D to the self-adaptive turn-off time generator and the power stage, and the self-adaptive turn-off time generator is used for sending a turn-off time adjusting signal D to the S end of the first RS trigger OFF 。
9. The DC/DC switching power supply control system according to claim 1 or 2, further comprising: a minimum on-time generator;
the minimum on-time generator is used for enabling the output of the self-adaptive off-time generator to be output to the duty ratio signal generator after a certain delay time within the overshoot time of the output voltage VOUT of the DC/DC switching power supply.
10. The DC/DC switching power supply control system according to claim 9, wherein when the DC/DC switching power supply is a Buck-Boost switching power supply, the duty signal generator includes: the feedback circuit comprises a feedback network, a third error amplifier, a second PWM comparator, a first RS trigger and a current sampling circuit;
the feedback network samples the output voltage VOUT of the DC/DC switching power supply and feeds the output voltage VOUT back to the non-inverting input end of the third error amplifier; the inverting input end of the third error amplifier receives a reference voltage VREF; the output end of the third error amplifier is connected to the inverting input end of the second PWM comparator;
the current sampling circuit samples the current of the power stage of the Buck-Boost switching power supply and feeds the current back to the non-inverting input end of the second PWM comparator; the output end of the second PWM comparator is connected to the R end of the first RS trigger; the Q end of the first RS trigger is used for sending a duty ratio signal D to the self-adaptive turn-off time generator and the power stage, and the self-adaptive turn-off time generator is used for sending a turn-off time adjusting signal D to the S end of the first RS trigger OFF ；
The input end of the minimum on-time generator is connected with the output end of the second PWM comparator and the output end of the self-adaptive off-time generator, and the output end of the minimum on-time generator is connected with the R end of the first RS trigger.
11. A DC/DC switching power supply control method, comprising:
generating a duty ratio signal D of the DC/DC switching power supply;
sampling the input and output voltages of the DC/DC switching power supply in real time; when any parameter in the input and output voltages changes, the off time T in the duty ratio signal D is dynamically adjusted along with the change of the parameter OFF To maintain the switching frequency of the DC/DC switching power supply constant.
12. The DC/DC switching power supply control method according to claim 11, wherein when any one of the input and output voltages changes, the off-time T in the duty signal D is dynamically adjusted according to the change of the parameter OFF To maintain the switching frequency of the DC/DC switching power supplyThe constancy of the ratio, including:
adjusting the charging time of the capacitor CtOFF, comprising: acquiring voltage at two ends of a capacitor CtOFF, when the voltage at the two ends of the capacitor CtOFF is reduced to be lower than reference voltage Vref, controlling the capacitor CtOFF to discharge when an original duty ratio signal D of the DC/DC switching power supply is at a high level, controlling the capacitor CtOFF to charge when the original duty ratio signal D is at a low level, and controlling the charging current to be a preset value ItOFF; controlling the capacitor CtOFF to discharge when the voltage at two ends of the capacitor CtOFF exceeds the reference voltage Vref;
taking the charging time of the capacitor CtOFF as the corrected turn-off time T OFF ；
The value requirements of the preset value ItOFF and the reference voltage Vref are as follows: off time T OFF The switching frequency of the DC/DC switching power supply is constant along with the variation of the input and output voltages of the DC/DC switching power supply.
13. The DC/DC switching power supply control method of claim 11, wherein the dynamically adjusting the off-time T in the duty cycle signal D as the parameter changes during the time that the output voltage VOUT of the DC/DC switching power supply overshoots OFF And replacing with:
dynamically delay adjusting the off-time T in the duty cycle signal D as the parameter changes OFF 。
14. A DC/DC switching power supply chip, comprising: the power stage and the control system of the DC/DC switching power supply are arranged on the substrate; the control system is a DC/DC switching power supply control system according to any one of claims 1 to 10.
15. An electronic device, comprising: the DC/DC switching power supply control system according to any one of claims 1 to 10.
CN202211083067.7A 2022-09-06 2022-09-06 DC/DC switching power supply control system, method, chip and electronic equipment Pending CN115360904A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117254671A (en) * 2023-11-17 2023-12-19 茂睿芯（深圳）科技有限公司 Switching frequency control system based on variable turn-off time

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117254671A (en) * 2023-11-17 2023-12-19 茂睿芯（深圳）科技有限公司 Switching frequency control system based on variable turn-off time
CN117254671B (en) * 2023-11-17 2024-03-01 茂睿芯（深圳）科技有限公司 Switching frequency control system based on variable turn-off time

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