CN112953186A - Ripple compensation circuit and method, switching power supply circuit and conduction time control method - Google Patents
Ripple compensation circuit and method, switching power supply circuit and conduction time control method Download PDFInfo
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- CN112953186A CN112953186A CN201911264920.3A CN201911264920A CN112953186A CN 112953186 A CN112953186 A CN 112953186A CN 201911264920 A CN201911264920 A CN 201911264920A CN 112953186 A CN112953186 A CN 112953186A
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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
- H02M1/00—Details of apparatus for conversion
- H02M1/14—Arrangements for reducing ripples from dc input or output
- H02M1/143—Arrangements for reducing ripples from dc input or output using compensating arrangements
Abstract
The application provides a ripple compensation circuit, a ripple compensation method, a switching power supply circuit and a conduction time control method. The ripple compensation circuit includes: the output alternating current signal response module is respectively connected with the switching end of the switching power supply circuit and the first input end of the adder, and is used for generating a target alternating current voltage and transmitting the target alternating current voltage to the adder; the load direct current signal response module is respectively connected with the input end of the load circuit and the second input end of the adder, and is used for generating a target direct current voltage and transmitting the target direct current voltage to the adder; the output end of the adder is connected with the control end of the switching power supply circuit and used for superposing the target alternating-current voltage and the target direct-current voltage to obtain ripple compensation voltage which is fed back to the control end, and the ripple compensation voltage is fed back to the switching power supply circuit to enable an output signal to be constant. The ripple compensation cost of the switching power supply circuit can be reduced, and the performance of the switching power supply is improved.
Description
Technical Field
The application relates to the field of switching power supplies, in particular to a ripple compensation circuit, a ripple compensation method, a switching power supply circuit and a conduction time control method.
Background
With the advance of technology, the power required by the base station is gradually increased, and accordingly, a power supply with large output power is required to adapt to the increasing power demand.
The high-voltage direct-current conversion of the constant on-time control into the low-voltage direct-current power supply is widely applied due to the advantages of high power, high transient response speed, high conversion efficiency under light load and the like. A Constant On Time control Circuit (COT) is usually used to achieve Constant switching frequency. Meanwhile, the control based on the output voltage ripple can have faster transient response speed, and particularly, the switching frequency can be constant by adopting a self-adaptive constant on-time control mode.
In order to enable the system to get rid of the limitation of Equivalent Series Resistance (ESR) and enable the system to stably operate under the condition of low ESR, information reflecting inductance current needs to be introduced into the system as feedback, so that the stability of loop control is realized. The current common mode is to arrange a ripple compensation circuit at the periphery of the system, which not only additionally increases the area of the system PCB board, but also needs additional devices, resulting in increased ripple compensation cost. Moreover, ripple compensation parameters are influenced by changes of peripheral components, compensation performance cannot be optimal, and usability is limited.
Disclosure of Invention
The application provides a ripple compensation circuit, a ripple compensation method, a switching power supply circuit and a conduction time control method.
The embodiment of the application provides a ripple compensating circuit, places in switching power supply circuit, include: the device comprises an output alternating current signal response module, a load direct current signal response module and an adder; the output alternating current signal response module is respectively connected with the switching end of the switching power supply circuit and the first input end of the adder, and is used for generating a target alternating current voltage and transmitting the target alternating current voltage to the adder, wherein the variation trend of the target alternating current voltage is the same as that of the inductive current;
the load direct current signal response module is respectively connected with the input end of the load circuit and the second input end of the adder, and is used for generating a target direct current voltage and transmitting the target direct current voltage to the adder, wherein the variation trend of the target direct current voltage is the same as that of the output signal;
the output end of the adder is connected with the control end of the switching power supply circuit and used for superposing the target alternating-current voltage and the target direct-current voltage to obtain ripple compensation voltage and feeding the ripple compensation voltage back to the control end, and the ripple compensation voltage is used for feeding the information of the inductive current and the information of the output signal back to the switching power supply circuit so as to keep the output signal constant;
the switch power supply circuit is used for providing the output signal for the load circuit, and the inductor is configured between the switch end of the switch power supply circuit and the input end of the load circuit, and is used for filtering an initial signal output by the switch end of the switch power supply circuit to obtain the output signal and sending the output signal to the input end of the load circuit.
The embodiment of the present application provides a ripple compensation method, which is applied to the ripple compensation circuit in any one of the embodiments of the present application, and the ripple compensation method includes:
generating a target alternating-current voltage through an output alternating-current signal response module, and transmitting the target alternating-current voltage to the adder, wherein the variation trend of the target alternating-current voltage is the same as that of the inductive current;
generating a target direct-current voltage through a load direct-current signal response module, and transmitting the target direct-current voltage to the adder, wherein the variation trend of the target direct-current voltage is the same as that of the output signal;
superposing the target alternating-current voltage and the target direct-current voltage through an output end of an adder to obtain ripple compensation voltage, and feeding the ripple compensation voltage back to a control end of the switching power supply circuit, wherein the ripple compensation voltage is used for feeding back information of the inductive current and information of the output signal to the switching power supply circuit so as to make the output signal constant;
the switch power supply circuit is used for providing the output signal for the load circuit, and the inductor is configured between the switch end of the switch power supply circuit and the input end of the load circuit, and is used for filtering an initial signal output by the switch end of the switch power supply circuit to obtain the output signal and sending the output signal to the input end of the load circuit.
The embodiment of the application provides a switching power supply circuit, includes: the ripple compensation circuit, the feedback control circuit, the constant on-time control circuit, the trigger, the driving circuit, the PMOS and the NMOS which are applied to any one of the embodiments of the present application,
the ripple compensation circuit is respectively connected with the switching end of the switching power supply circuit and the feedback control circuit and is used for generating ripple compensation voltage, and the ripple compensation voltage comprises information of inductive current and information of output signals;
the feedback control circuit is respectively connected with the input end of the switching power supply circuit, the feedback end of the switching power supply circuit and the first input end of the trigger, and is used for generating a feedback control signal according to the received feedback voltage and the ripple compensation voltage, wherein the feedback voltage is obtained by dividing the output voltage;
the output end of the constant on-time control circuit is connected with the second input end of the trigger and used for generating an on-time control signal;
the output end of the trigger is connected with the input end of the driving circuit and used for generating a driving signal according to the conduction time control signal and the feedback control signal;
the first output end of the driving circuit is connected with the grid electrode of the PMOS, the second output end of the driving circuit is connected with the grid electrode of the NMOS, and the driving circuit is used for controlling the connection and disconnection of the PMOS and the NMOS respectively based on the driving signal;
the source electrode of the PMOS is connected with the input end of the switch power supply circuit, the drain electrode of the PMOS is respectively connected with the drain electrode of the NMOS and the switch end of the switch power supply circuit, the source electrode of the NMOS is grounded, and the PMOS and the NMOS are used for jointly cooperating to control the rise and fall of the output voltage of the switch power supply circuit so as to ensure that the switching frequency of the switch power supply circuit is constant.
The embodiment of the present application provides a method for controlling conduction time, which is applied to a switching power supply circuit described in any one of the embodiments of the present application, and the method includes:
generating ripple compensation voltage through a ripple compensation circuit, wherein the ripple compensation voltage comprises information of inductive current and information of output signals;
generating a feedback control signal according to the received feedback voltage and the ripple compensation voltage through a feedback control circuit, wherein the feedback voltage is obtained by dividing the output voltage;
generating an on-time control signal through a constant on-time control circuit;
generating a driving signal according to the on-time control signal and the feedback control signal through a trigger;
respectively controlling the on-off of the PMOS and the NMOS based on the driving signal through a driving circuit;
the PMOS is combined with the NMOS to cooperatively control the rise and fall of the output voltage of the switching power supply circuit so as to ensure that the switching frequency of the switching power supply circuit is constant.
The ripple compensation circuit, the method, the switching power supply circuit and the on-time control method provided by the embodiment of the application generate the target alternating current voltage with the same variation trend as the inductive current and the target direct current voltage with the same variation trend as the output signal through the ripple compensation circuit arranged in the switching power supply circuit, and superpose and generate the ripple compensation voltage which is fed back to the switching power supply circuit to compensate the ripple compensation voltage containing the inductive current information to the output voltage generated in the switching power supply circuit, reduce the ripple in the output voltage and ensure the output voltage and the output current to be constant, thereby ensuring the switching frequency of the switching power supply circuit to be constant, realizing the stable work of a loop, solving the problems of cost increase and power supply performance reduction caused by the increase of circuit area and devices due to the configuration of the ripple compensation circuit at the periphery of the switching power supply circuit in the prior art, the ripple compensation circuit is arranged inside the switching power supply circuit in a built-in mode, peripheral devices and circuit area of the switching power supply circuit are reduced, cost is reduced, meanwhile, the influence of the peripheral devices on the ripple compensation circuit is reduced, the compensation performance of the ripple compensation circuit is improved, and therefore the performance of the switching power supply is improved.
With regard to the above embodiments and other aspects of the present application and implementations thereof, further description is provided in the accompanying drawings description, detailed description and claims.
Drawings
Fig. 1 is a schematic diagram of a ripple compensation circuit in an embodiment of the present application;
fig. 2 is a schematic diagram of an application scenario of a ripple compensation circuit in an embodiment of the present application;
fig. 3 is a schematic diagram of an output ac signal response module in the ripple compensation circuit according to the embodiment of the present application;
fig. 4 is a schematic circuit diagram of an output ac signal response module in the ripple compensation circuit according to the embodiment of the present application;
fig. 5 is a schematic diagram of a load dc signal response module in the ripple compensation circuit according to the embodiment of the present application;
fig. 6 is a schematic circuit diagram of a load dc signal response module in the ripple compensation circuit according to the embodiment of the present application;
fig. 7 is a schematic circuit diagram of a ripple compensation circuit in an embodiment of the present application;
fig. 8 is a schematic diagram of an adder in the ripple compensation circuit according to the embodiment of the present application;
fig. 9 is a schematic diagram of a dc signal terminal of the ripple compensation circuit according to the embodiment of the present application grounded;
fig. 10 is a schematic diagram of a dc signal terminal of the ripple compensation circuit in an embodiment of the present application without being grounded;
fig. 11 is a flowchart of a ripple compensation method in an embodiment of the present application;
fig. 12 is a schematic diagram of a switching power supply circuit in an embodiment of the present application;
fig. 13 is a schematic diagram of a feedback control circuit in the switching power supply circuit according to the embodiment of the present application;
fig. 14 is a schematic diagram of an application scenario in which the switching power supply circuit in the embodiment of the present application is applied;
fig. 15 is a schematic voltage value diagram of the ripple compensation voltage in the embodiment of the present application;
fig. 16 is a flowchart of an on-time control method in the embodiment of the present application.
Detailed Description
To make the objects, technical solutions and advantages of the present application more apparent, embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be noted that the embodiments and features of the embodiments in the present application may be arbitrarily combined with each other without conflict.
Examples
Fig. 1 is a schematic diagram of a ripple compensation circuit provided in an embodiment of the present application, where the present embodiment is applicable to a switching power supply circuit controlled by a constant on-time, and performs ripple compensation on an output voltage of the switching power supply circuit, as shown in fig. 1, a ripple compensation circuit 100 is built in the switching power supply circuit, and specifically includes: an output ac signal response module 110, a load dc signal response module 120, and an adder 130.
Fig. 2 is a schematic diagram of a connection structure of the ripple compensation circuit 100, the switching power supply circuit 200, the inductor 300 and the load circuit 400, and specifically, as shown in fig. 2,
the output alternating current signal response module 110 is respectively connected to the switch terminal 101 of the switching power supply circuit 200 and the first input terminal of the adder 130, and is configured to generate a target alternating current voltage, and transmit the target alternating current voltage to the adder 130, where a variation trend of the target alternating current voltage is the same as a variation trend of the inductor current;
the load dc signal response module 120 is respectively connected to the input terminal 102 of the load circuit 400 and the second input terminal of the adder 130, and is configured to generate a target dc voltage, and transmit the target dc voltage to the adder, where a variation trend of the target dc voltage is the same as a variation trend of the output signal;
the output end of the adder 130 is connected to the control end 103 of the switching power supply circuit 200, and is configured to superimpose the target ac voltage and the target dc voltage to obtain a ripple compensation voltage, and feed the ripple compensation voltage back to the control end 103, where the ripple compensation voltage is configured to feed back information of the inductive current and information of the output signal to the switching power supply circuit 200, so that the output signal is constant;
the switching power supply circuit 200 is configured to provide an output signal for the load circuit 400, and the inductor 300 is configured between a switching end of the switching power supply circuit 200 and an input end of the load circuit 400, and is configured to filter an initial signal output by the switching end 101 of the switching power supply circuit 200 to obtain an output signal.
Specifically, the output ac signal response module 110 is configured to generate a target ac voltage, the load dc signal response module 120 is configured to generate a target dc voltage, and the adder 130 is configured to superimpose the target ac voltage and the target dc voltage. The target alternating voltage has the same variation trend as the variation trend of the inductive current, and can reflect the variation of the inductive current flowing through. The variation trend of the target dc voltage is the same as the variation trend of the output signal, and particularly, the variation trend of the target dc voltage is the same as the variation trend of the output voltage, that is, the variation trend of the load voltage applied to the load circuit 400. Therefore, the superposed ripple compensation voltage can reflect the change of the inductive current and the change of the output signal.
It is understood that the load dc signal response module 120 provides the target dc voltage, and on one hand, establishes a dc offset point for the ripple compensation voltage, so that the adder can feed the ripple compensation voltage back to the switching power supply circuit under the operation of the dc offset point. On the other hand, the variation trend of the output voltage is fed back to the ripple compensation voltage, so that the switching power supply circuit can quickly respond according to the transient variation of the output voltage when receiving the ripple compensation voltage, and the transient response speed of the switching power supply circuit to the load is improved.
The switching power supply circuit 200 reduces the working performance of the load circuit 400 due to the existence of noise, for example, an ac signal, in the output switching signal directly output through the switching terminal 102, and the output switching signal is filtered by providing the inductor 300 between the switching power supply circuit 200 and the load circuit 400 to form a dc output signal, which is provided to the load circuit 400 through the input terminal 102 of the load circuit 400, so that the load circuit 400 normally and stably operates.
In an application scenario of the embodiment of the application, the switching power supply circuit 200 is a DC-DC conversion Direct Current-Direct Current (DC-DC) circuit based on-time control.
The switching power supply circuit 200 adopts a control mode based on output voltage ripple, and because the output voltage ripple contains information of inductive current, the control based on the output voltage ripple can have faster transient response speed, and especially the control mode of adaptive constant on-time can make the switching frequency constant, thereby simplifying the design of emi filter. However, in the control method based on the output voltage ripple, when the resistance value of the series resistor of the output capacitor is very small or even zero, the ripple of the output voltage and the current flowing through the inductor have a fixed 90-degree phase shift, and at this time, the control method based on the output voltage ripple cannot effectively control the current in the circuit, so that the loop control is very unstable. And this application sets up ripple compensating circuit 100 in switching power supply circuit 200 is inside, during ripple compensating voltage that will contain the information of inductive current in the circuit compensates output voltage, guarantees to control the electric current and the voltage stability of switching power supply circuit 200 output, guarantees that switching frequency is stable to, guarantee load circuit steady operation.
In fact, the switching power supply circuit 200 receives the feedback voltage through the feedback terminal thereof, and the feedback voltage and the ripple compensation voltage cooperate to control the on/off of the PMOS and the NOMS in the switching power supply circuit to control the rise and fall of the output voltage and the rise and fall of the output current, so as to make the output signal constant.
Since the ac component in the initial signal of the switching power supply circuit 200 is filtered by the inductor 300, the output ac signal response module 120 needs to obtain the transmission signal between the switching power supply circuit 200 and the inductor 300 to extract the ac component in the initial signal of the switching power supply circuit 200 and generate the target ac voltage that varies with the variation of the ac component. It will be appreciated that the initial signal corresponds to a current signal including the inductor current, and thus the useful ac component may reflect information about the inductor current. Coupling the target ac voltage into the summer generates a ripple compensation voltage that may reflect changes in the inductor current.
In addition, after the initial signal of the switching power supply circuit 200 passes through the inductor 300, an output signal is formed, that is, the signal reaching the input terminal 102 of the load circuit 400 is an output signal, and at this time, the output signal is a direct current signal. The load dc signal response module 120 may obtain a transmission signal between the load circuit 400 and the inductor 300 and generate a target dc voltage varying with the transmission signal. It is understood that the voltage signal corresponding to the output signal is the output voltage, and thus, the variation trend of the target dc voltage is the same as the variation trend of the output voltage. Meanwhile, transient change of the target direct current voltage is coupled into the adder to generate ripple compensation voltage, and the ripple compensation voltage can reflect change of the output voltage. Meanwhile, the target dc voltage is used to provide a dc bias point, so that the adder 130 feeds the ripple compensation voltage back to the switching power supply circuit 200 through the control terminal 103. The output end of the adder 130 is used for communicating the switching power supply circuit 200 and the ripple compensation circuit 100, and is used for transmitting the ripple compensation voltage output by the ripple compensation circuit 100 to the switching power supply circuit 200, and the control end 103 is used for communicating the switching power supply circuit 200 and the ripple compensation circuit 100, and is used for the switching power supply circuit 200 to receive the ripple compensation voltage output by the ripple compensation circuit 100.
The ripple compensation circuit, the method, the switching power supply circuit and the on-time control method provided by the embodiment of the application generate the target alternating current voltage with the same variation trend as the inductive current and the target direct current voltage with the same variation trend as the output signal through the ripple compensation circuit arranged in the switching power supply circuit, and superpose and generate the ripple compensation voltage which is fed back to the switching power supply circuit to compensate the ripple compensation voltage containing the inductive current information to the output voltage generated in the switching power supply circuit, reduce the ripple in the output voltage and ensure the output voltage and the output current to be constant, thereby ensuring the switching frequency of the switching power supply circuit to be constant, realizing the stable work of a loop, solving the problems of cost increase and power supply performance reduction caused by the increase of circuit area and devices due to the configuration of the ripple compensation circuit at the periphery of the switching power supply circuit in the prior art, the ripple compensation circuit is arranged inside the switching power supply circuit in a built-in mode, peripheral devices and circuit area of the switching power supply circuit are reduced, cost is reduced, meanwhile, the influence of the peripheral devices on the ripple compensation circuit is reduced, the compensation performance of the ripple compensation circuit is improved, and therefore the performance of the switching power supply is improved.
In an exemplary embodiment, as shown in fig. 3, the output ac signal response module 110 includes: an integrating circuit 111 and an ac coupling circuit 112.
The integration circuit 111 is configured to integrate the initial signal to obtain an integration voltage, where a variation trend of the integration voltage is the same as a variation trend of the inductor current; the ac coupling circuit 112 is configured to extract an ac component from the integrated voltage as a target ac voltage, and to couple the target ac voltage to the adder.
It can be understood that the initial current corresponding to the initial signal is the current flowing through the inductor, and thus, the change of the inductor current can be characterized by the change of the initial signal, so that the change trend of the initial signal is the same as the change trend of the inductor current. The trend of the integrated voltage formed for the initial signal is used to characterize the trend of the inductor current. However, the integrated voltage includes a dc component and an ac component, wherein the ac component includes information of the inductor current, which is useful information. The target alternating voltage is an alternating component in the integral voltage and is used for representing the variation trend of the inductive current.
In fact, the inductor current is a triangular wave signal, and accordingly, the integral voltage is a superposition of a triangular wave voltage and a target direct current voltage, and the target alternating current voltage is a triangular wave signal.
The ac coupling circuit 112 is used to extract a target ac voltage from the integrated voltage, form a ripple compensation voltage and feed back the ripple compensation voltage to the switching power supply circuit, so that the switching power supply circuit can respond to the change of the inductor current quickly.
The variation trend of the inductive current can be accurately fitted through the integrating circuit, the integrating voltage representing the variation trend is generated, useful information, namely alternating current components, can be extracted from the integrating voltage through the alternating current coupling circuit and is coupled to the adder as target alternating current voltage to form ripple compensation voltage, and therefore the ripple compensation voltage contains the variation information of the inductive current, the information of the inductive current is compensated to feedback, the switching frequency of the switching power supply circuit is guaranteed to be constant, and the load circuit is guaranteed to work stably.
In an exemplary embodiment, the integration circuit includes a first resistor and a first capacitor, which together form a series circuit to integrate the output voltage; the first end of the first resistor is connected with the switch end of the switch power supply circuit, and the second end of the first resistor is connected with the first end of the first capacitor; the second end of the first capacitor is connected with the direct current signal end, and the voltage of the direct current signal end is direct current voltage.
The first resistor and the first capacitor are connected in series to form an integrating circuit. The first capacitor is used for charging and discharging when the output voltage changes, for example, when the output voltage is reduced, the first capacitor discharges; when the output voltage increases, the first capacitor charges. Therefore, the voltage across the first capacitor can be used for representing the change condition of the initial signal, namely the change condition of the inductive current.
The voltage of the direct current signal end is direct current voltage, which indicates that no alternating current signal exists at the direct current signal end, so that the first capacitor is not interfered by alternating current signals except the initial signal, and the alternating current component in the integral voltage only comprises inductive current information. Specifically, the dc signal terminal may be ground, or may be another port outputting dc voltage.
The integrating circuit with the series connection of the capacitor and the resistor is configured, so that the integrating circuit can be simplified, the feedback of the inductive current information can be realized quickly, and the realization cost of the feedback of the inductive current information can be reduced.
It should be noted that the integrating circuit may also be a circuit in other forms, and this embodiment of the present application only shows one case, and a plurality of resistors may also be configured or a connection relationship between a resistor and a capacitor may be adjusted as needed, and this is not limited in this embodiment of the present application.
In an exemplary embodiment, the ac coupling circuit includes a second capacitor, a first terminal of the second capacitor is connected to a first terminal of the first capacitor, and a second terminal of the second capacitor is connected to the first input terminal of the adder.
The second capacitor is used for filtering a direct current component in the integrated voltage, reserving an alternating current component in the integrated voltage as a target alternating current voltage, and coupling the target alternating current voltage into the adder so that the adder can superpose the target alternating current voltage on the ripple compensation voltage.
Only one capacitor is configured as an alternating current coupling circuit, so that alternating current components in the integral voltage can be quickly extracted and superposed into ripple compensation voltage, the feedback of inductive current information is quickly realized, and the realization cost of the feedback of the inductive current information is reduced.
In one example, as shown in fig. 4, the integrating circuit 111 is a series circuit of a first resistor R1 and a first capacitor C1. The ac coupling circuit 112 is a second capacitor C2. Vsw is the voltage at the switching terminal of the switching power supply circuit. Where V3 is a dc voltage, and may be 0 or other dc voltage amplitude.
Accordingly, the amplitude V1 of the AC component at the point V1acThat is, the amplitude of the target ac voltage is:
V1ac＝IR1/C1*ton
wherein, IR1Ton is the on-time of the switching power supply circuit for the current flowing through the first resistor R1.
In addition, when the controller topology of the switching power supply circuit is a BUCK (BUCK chopper) structure, the switching power supply circuit outputs a power supply signal, i.e., an initial signal, through the dual power transistor, and if the on duty ratio of the upper tube in the dual power transistor is D, since the dc current flowing through the first resistor R1 is blocked by the first capacitor C1 and the second capacitor C2, the amplitude V1 of the dc component at the V1 point isdcI.e. the level of VswMean value, thus the amplitude V1 of the DC component at point V1dcComprises the following steps:
meanwhile, when the upper tube is conducted, the current flowing through the resistor R1 is:
IR1＝(VIN-VOUT)/R1
thus, the amplitude of the target ac voltage is:
V1ac＝IR1/C1*ton＝(VIN-VOUT)*ton/(R1*C1)
in an exemplary embodiment, as shown in fig. 5, the load dc signal response module includes: a voltage divider circuit 121 and a dc coupling circuit 122; a voltage divider circuit 121 configured to divide an output voltage corresponding to the output signal to generate a target dc voltage; and a dc coupling circuit 122 for coupling the transient change of the target dc voltage to the adder.
It is understood that the output voltage corresponding to the output signal is the load voltage across the load circuit 400, which is actually a dc voltage. The dc voltage is divided by the voltage divider circuit 121, and the target dc voltage can be obtained.
In practice, the voltage divider circuit is used to extract a dc voltage from the output voltage as a target dc voltage. The direct current coupling circuit is used for feeding back the transient change of the output voltage to the adder to form ripple compensation voltage and feeding the ripple compensation voltage back to the switching power supply circuit, so that the switching power supply circuit can quickly respond to the transient change of the output voltage.
Directly draw output voltage through bleeder circuit, generate target DC voltage fast to in coupling the transient variation of target DC voltage to the adder through direct current coupling circuit, form ripple compensating voltage, thereby realize that ripple compensating voltage contains output voltage's change information, thereby realize that output voltage's transient variation arouses ripple compensating voltage's change fast, make switching power supply circuit quick response output voltage's transient variation, improve switching power supply circuit's stability.
In one exemplary embodiment, the voltage dividing circuit includes a second resistor and a third resistor; the second resistor and the third resistor jointly form a series circuit to divide the output voltage; the first end of the second resistor is connected with the second end of the inductor, the second end of the second resistor is respectively connected with the first end of the third resistor and the second input end of the adder, and the voltage at the two ends of the third resistor is target direct-current voltage; the second end of the third resistor is grounded.
The two resistors are configured to form the voltage division circuit, so that the voltage division circuit can be simplified, the direct-current voltage can be quickly obtained from the output voltage, the implementation cost of the direct-current bias point is reduced, meanwhile, the establishment efficiency of the direct-current bias point is improved, reestablishment in each switching period is not needed, and the stability of the switching power supply circuit is improved.
In an exemplary embodiment, the dc coupling circuit includes a third capacitor; the third capacitor is connected with the second resistor in parallel.
By only configuring one capacitor as the direct current coupling circuit, the transient variation of the output voltage can be quickly extracted and superposed into the ripple compensation voltage, so that the feedback of the transient variation information of the output voltage is quickly realized, and the realization cost of the transient variation information of the feedback load is reduced.
In one example, as shown in fig. 6, the voltage dividing circuit 121 is a series circuit of a second resistor R2 and a third resistor R3. The dc coupling circuit 122 is a third capacitor C3. VOUTIs the output voltage.
Accordingly, the magnitude of the target dc voltage at point V2 is:
V2＝VOUT*R3/(R2+R3)
in one example, as shown in fig. 7, the adder adds the target ac voltage and the target dc voltage to obtain a ripple compensation voltage Vramp:
Vramp＝V1ac+V2＝(VIN-VOUT)*ton/(R1*C1)+VOUT*R3/(R2+R3)
in an exemplary embodiment, the adder is a P-type metal oxide semiconductor field effect transistor PMOS, a source of the PMOS serves as a first input terminal of the adder, a gate of the PMOS serves as a second input terminal of the adder, a source of the PMOS serves as an output terminal of the adder, and a drain of the PMOS is grounded.
A PMOS for superimposing the input of the source and the input of the gate may be employed as the adder. And when the grid voltage of the PMOS meets the threshold condition, the PMOS is conducted, and at the moment, the voltage value at the source electrode of the PMOS is the voltage value obtained by superposing the input voltage of the source electrode and the input voltage of the grid electrode, so that the voltage addition is realized.
As shown in FIG. 8, the adder is implemented by a PMOS M1, and when M1 is turned on, the power current I1 flows through M1, so that a DC voltage difference V is generated between the source and the gate of M1gsTherefore, the final Vramp voltage is obtained by passing the DC component at V2 through a resistor of magnitude VgsIs shifted and added to the ac component at V1.
The dc level at Vramp is:
Vramp_dc＝V2+Vgs＝VOUT*R3/(R2+R3)+Vgs
wherein, the source and the gate with Vgs of M1 generate DC voltage difference, and V1 is omittedacThe voltage loss of the source coupled to M1, Vramp is accordingly:
Vramp＝V1ac+Vramp_dc＝(VIN-VOUT)*ton/(R1*C1)+VOUT*R3/(R2+R3)+Vgs
in one example, the dc signal terminal includes a ground or a second terminal of the second resistor.
In one example, as shown in fig. 9, V3 is ground.
In one example, as shown in fig. 10, V3 is the same as V2.
Fig. 11 is a flowchart of a ripple compensation method provided in the embodiment of the present application, where the present embodiment is applicable to a switching power supply circuit with constant on-time control, and the ripple compensation method is used for performing ripple compensation on an output voltage of the switching power supply circuit, and as shown in fig. 11, the method specifically includes:
s110, generating a target alternating-current voltage through an output alternating-current signal response module, and transmitting the target alternating-current voltage to the adder, wherein the variation trend of the target alternating-current voltage is the same as that of the inductive current;
s120, generating a target direct-current voltage through a load direct-current signal response module, and transmitting the target direct-current voltage to the adder, wherein the variation trend of the target direct-current voltage is the same as that of the output signal;
s130, superimposing the target ac voltage and the target dc voltage through an output end of the adder to obtain a ripple compensation voltage, and feeding back the ripple compensation voltage to a control end of the switching power supply circuit, where the ripple compensation voltage is used to feed back information of the inductive current and information of the output signal to the switching power supply circuit, so as to make the output signal constant;
the switch power supply circuit is used for providing the output signal for the load circuit, and the inductor is configured between the switch end of the switch power supply circuit and the input end of the load circuit, and is used for filtering an initial signal output by the switch end of the switch power supply circuit to obtain the output signal and sending the output signal to the input end of the load circuit.
Specifically, the switching power supply circuit is a direct current-direct current conversion circuit based on-time control, and specifically includes a BUCK structure, that is, the switching power supply output is controlled through a double-power tube. The switching power supply circuit controls the on-off of the double power tubes by using the divided voltage of the load circuit as a feedback voltage, but the feedback voltage does not include current information, so that the control mode of the switching power supply circuit is unstable, and the output switching frequency is unstable.
This application is through on the basis that has feedback voltage, further according to inductive current's information generation ripple offset voltage to feed back to switching power supply circuit in, so that switching power supply circuit can combine inductive current information according to feedback voltage, control double power tube break-make, thereby, guarantee switching power supply circuit's output stable, guarantee switching frequency stability promptly, and output voltage is invariable.
In addition, the switching power supply circuit receives the feedback voltage through the feedback end, and the feedback voltage and the ripple compensation voltage are matched together to control the on-off of the double-power tube, wherein the common matching mode can be that the feedback voltage and the ripple compensation voltage are overlapped to generate a control signal to control the on-off of the double-power tube, or can be that the control signal is generated respectively to control the on-off of the double-power tube in a cascade mode.
Through the ripple compensation method, a target alternating current voltage with the same variation trend as the inductive current and a target direct current voltage with the same variation trend as the output signal can be generated, and the ripple compensation voltage is generated in an overlapping way and fed back to the inside of the switching power supply circuit so as to compensate the ripple compensation voltage containing inductive current information into the output voltage generated in the switching power supply circuit, reduce the ripple in the output voltage and ensure the output voltage and the output current to be constant, thereby ensuring the switching frequency of the switching power supply circuit to be constant, reducing devices and circuit areas at the periphery of the switching power supply circuit, reducing the cost, simultaneously reducing the influence of peripheral devices on the ripple compensation circuit, improving the compensation performance of the ripple compensation circuit, and improving the performance of the switching power supply, in addition, a direct current bias point is directly established according to the output signal to generate the target direct current voltage, the method has the advantages that the establishment process of the direct current bias point is simplified, the establishment speed of the direct current bias point is increased, the adder can feed back the ripple compensation voltage to the interior of the switching power supply circuit quickly, and therefore the stability of the switching power supply circuit is guaranteed.
Fig. 12 is a schematic diagram of a switching power supply circuit provided in an embodiment of the present application, where the present embodiment is applicable to a switching power supply circuit with constant on-time control, and the case of performing ripple compensation on an output voltage of the switching power supply circuit is that, as shown in fig. 11, a switching power supply circuit 200 specifically includes: the ripple compensation circuit 100, the feedback control circuit 210, the constant on-time control circuit 220, the flip-flop 230, the driving circuit 240, the PMOS M2, and the NMOS M3 according to any of the embodiments of the present application,
the ripple compensation circuit 100 is respectively connected to the switching end of the switching power supply circuit 300 and the feedback control circuit 210, and is configured to generate a ripple compensation voltage, where the ripple compensation voltage includes information of the inductive current and information of the output signal;
the feedback control circuit 210 is respectively connected to the input terminal of the switching power supply circuit 200, the feedback terminal of the switching power supply circuit 200, and the first input terminal of the trigger 230, and configured to generate a feedback control signal according to the received feedback voltage and ripple compensation voltage, where the feedback voltage is obtained by dividing the output voltage;
an output terminal of the constant on-time control circuit 220 is connected to a second input terminal of the flip-flop 230 for generating an on-time control signal;
the output terminal of the flip-flop 230 is connected to the input terminal of the driving circuit 240, and is configured to generate a driving signal according to the on-time control signal and the feedback control signal;
a first output end of the driving circuit 240 is connected to the gate of the PMOS M2, and a second output end is connected to the gate of the NMOS M3, for controlling the on/off of the PMOS M2 and the NMOS M3 respectively based on the driving signal;
the source electrode of the PMOS M2 is connected with the input end of the switch power supply circuit, the drain electrode is respectively connected with the drain electrode of the NMOS M3 and the switch end of the switch power supply circuit, the source electrode of the NMOS M3 is grounded, and the PMOS M2 and the NMOS M3 are used for jointly cooperating to control the rising and falling of the output voltage of the switch power supply circuit so as to ensure the constant switching frequency of the switch power supply circuit and ensure the stable work of a system loop.
The switching power supply circuit is a direct current-direct current conversion circuit based on-time control, and specifically comprises a BUCK structure, namely the switching power supply output is controlled through double power tubes (namely PMOS M2 and NMOS M3). The feedback control circuit 210 generates a feedback control signal in combination with the ripple compensation voltage provided by the ripple compensation circuit 100 and the feedback voltage received through the feedback terminal of the switching power supply circuit 200, so that the switching power supply circuit 200 responds in time according to the output condition to adjust the output. Wherein, ripple compensating voltage contains the inductive current information, and feedback voltage includes output voltage's information to, switching power supply circuit 200 can be in time according to electric current and voltage information adjustment output, guarantees output voltage and output current invariable, thereby guarantees that switching frequency is stable, and system loop is steady operation.
The constant on-time control circuit 220 is configured to generate an on-time control signal, i.e., a Pulse Width Modulation (PWM) signal, to control the PMOS M2 and the NMOS M3 to be turned on or off.
The flip-flop 230 is configured to generate a driving signal to control the on/off of the PMOS M2 and the NMOS M3 in combination with the on-time control signal and the feedback control signal. Flip-flop 230 is a logic cell circuit, and usually has two stable states (e.g., logic 1 and logic 0), which can be switched by a trigger signal, and when the trigger signal disappears, the circuit can keep the previous state.
Illustratively, the flip-flop 230 is an RS flip-flop. The first input terminal of the flip-flop 230 is an S terminal and is connected to the feedback control circuit 210; the second input terminal of the flip-flop 230 is an R terminal and is connected to the constant on-time control circuit 220.
It can be understood that the driving signal output by the flip-flop 230 is small and is not enough to drive the M2 and the M3 to be switched on and off, so that the driving circuit 240 is added between the flip-flops 230 and M2 and between the flip-flops 230 and M3, and the flip-flops output the driving signal are amplified to control the M2 and M3 to be switched on and off.
The driving circuit 240 is used for processing the driving signal and generating a control signal enough to drive the M2 and the M3 to respectively control the M2 and the M3 to be switched on and off. The driving circuit 240 is further configured to increase the dead time between the turn-on signal of M2 and the turn-on signal of M3 to achieve one MOS to be turned on at the same time. It can be understood that, the simultaneous conduction of M2 and M3 may cause component burnout, so that it is necessary to avoid the simultaneous conduction of M2 and M3, and the control signal generated by the driving circuit 240 according to the driving signal needs to ensure that M2 and M3 are staggered in conduction time, i.e. dead time is increased, so as to ensure that only one MOS is turned on at the same time, protect M2 and M3, and reduce power consumption of the dual power transistor.
The PMOS M2 and the NMOS M3 are switched on or off according to a control signal sent by the driving circuit 240, so that when the feedback voltage drops, the PMOS M2 is switched on, the NMOS M3 is switched off, the output voltage rises, and the feedback voltage rises; when the feedback voltage rises, the PMOS M2 is cut off, the NMOS M3 is turned on, the output voltage is reduced, the feedback voltage is reduced, the output voltage is ensured to be stabilized at a value, and the output voltage is ensured to be constant.
Through the built-in ripple compensating circuit in switching power supply circuit, can additionally reduce peripheral device of switching power supply circuit and circuit area, reduce cost, reduce the ripple compensating circuit simultaneously and receive the influence of peripheral device, improve ripple compensating circuit's compensation performance to improve switching power supply's performance.
In an exemplary embodiment, as shown in fig. 13, the feedback control circuit 210 includes: a reference circuit 211, an error amplifier 212, and a comparator 213;
the input end of the reference circuit 211 is connected to the input end of the switching power supply circuit 200, and the output end is connected to the non-inverting input end of the error amplifier, and is configured to generate a reference voltage according to an input voltage received from the input end of the switching power supply circuit 200;
an inverting input terminal of the error amplifier 212 is connected to the feedback terminal of the switching power supply circuit 200, and an output terminal thereof is connected to a non-inverting input terminal of the comparator 213, and is configured to receive the feedback voltage, amplify a difference between the feedback voltage and the reference voltage, and output an error amplified voltage, where a voltage value of the reference voltage is the same as a voltage value of the stabilized feedback voltage;
the comparator 213 has an inverting input terminal connected to the output terminal of the adder in the ripple compensation circuit 100, and an output terminal connected to the first input terminal of the flip-flop 230, and is configured to compare the ripple compensation voltage and the error amplification voltage and output a feedback control signal.
The inverting input terminal of the comparator 213 serves as the control terminal of the switching power supply circuit 200, and is used for receiving the ripple compensation voltage output by the adder in the ripple compensation circuit 100. The input of the switching power supply circuit 200 is used for accessing the main power supply, i.e. VINIn practice, the switching power supply circuit 200 is used to convert the power received by the input terminal into the required power, for example, from dc to dc, or from dc to ac, and there are other situations, and the embodiment of the present application is not limited thereto. The mains power supply is also used to supply power to the reference circuit.
It should be noted that the reference circuit, the constant on-time control circuit, and the driving circuit may implement corresponding functions with reference to the existing circuit, and the embodiments of the present application are not limited specifically.
In one example, fig. 14 is a schematic diagram of an application scenario of a switching power supply circuit with a built-in ripple compensation circuit.
The periphery of the switching power supply circuit 200 needs to be configured with an inductor 300, an output capacitor CL, a series resistor Esr of the output capacitor CL, a load resistor RL, a first reference resistor Rf1 and a second reference resistor Rf 2. The output capacitor CL is connected with the series resistor Esr in series, the first reference resistor Rf1 and the second reference resistor Rf2 are connected in series to form a voltage dividing circuit, and meanwhile, the series circuit of the output capacitor CL and the series resistor Esr, the voltage dividing circuit of the first reference resistor Rf1 and the second reference resistor Rf2 and the load resistor RL are connected in parallel. The load resistor RL is used as the load circuit 400, the voltage across the second reference resistor Rf2 is the feedback voltage, and the feedback terminal V of the switching power supply circuit 200FBAre connected.
The ripple compensation circuit 100 generates a ripple compensation voltage Vramp, and R2 and R3 are output voltages VOUTThe voltage dividing resistor is used for providing a direct current bias point for the adder M1, and the capacitor C3 divides the voltage V2 into an output voltage VOUTDirect connection for improving transient response of output voltage V when transient occurs in load circuitOUTCan be directly coupled to V2 through a capacitor C3, while the dc component of Vramp is determined by V2, so that the output voltage V isOUTThe transient change of (2) directly changes the direct current component of the ripple compensation voltage Vramp of the adder, so that the comparator 213 can respond quickly, and because the response path of the path to the output does not pass through the error amplifier 212, the response path is short, so that the response speed is higher than that of the traditional system; r1 and C1 form an integration circuit for the voltage V at the switch endSWIntegrating to generate a triangular wave ripple voltage V1, wherein the ripple voltage comprises a direct current component and an alternating current component, and useful information is alternating current information, so that the alternating current component is coupled into the adder through the C3; the adder adds the voltage V2 and the ac component V1 to generate a ripple voltage Vramp required for compensation, specifically:
Vramp＝(VIN-VOUT)*ton/(R1*C1)+VOUT*R3/(R2+R3)+Vgs
the voltage value of Vramp varies with the inductor current as shown in FIG. 15, where ILVesr is the voltage across the series resistance Esr of the output capacitor CL, which is the inductor current. When the ESR resistor is small, the ripple voltage Vesr of the ESR resistor reflecting the inductor current is very small, and then the Vramp voltage can also reflect the inductor current. Therefore, the problems that harmonic oscillation occurs in a switching power supply circuit due to the low ESR and small surface mounted tantalum capacitor or ceramic capacitor configured in a power supply system with high integration level, output voltage ripples become large, and stable work cannot be achieved are solved, and the stability of the switching power supply circuit is improved.
Fig. 16 is a flowchart of an on-time control method provided in the embodiment of the present application, which is applicable to a switching power supply circuit with constant on-time control, and the ripple compensation of the output voltage of the switching power supply circuit is performed in the embodiment, as shown in fig. 16, specifically includes:
s210, generating ripple compensation voltage through a ripple compensation circuit, wherein the ripple compensation voltage comprises information of inductive current and information of output signals;
s220, generating a feedback control signal according to the received feedback voltage and the ripple compensation voltage through a feedback control circuit, wherein the feedback voltage is obtained by dividing the output voltage;
s230, generating a conduction time control signal through a constant conduction time control circuit;
s240, generating a driving signal according to the on-time control signal and the feedback control signal through a trigger;
s250, respectively controlling the on-off of the PMOS and the NMOS based on the driving signal through a driving circuit;
and S260, combining the PMOS with the NMOS and cooperatively controlling the rise and fall of the output voltage of the switching power supply circuit so as to ensure that the switching frequency of the switching power supply circuit is constant.
Through obtaining the ripple compensating voltage who contains the inductive current information, combine feedback voltage to control PMOS and NMOS break-make respectively, realize reducing the ripple in the output voltage, guarantee output voltage and output current invariable, thereby guarantee switching power supply circuit's switching frequency invariant, and acquire ripple compensating voltage through adopting built-in ripple compensating circuit among the switching power supply circuit, can reduce switching power supply circuit outlying device and circuit area by volume, reduce cost, it receives the influence of peripheral device to reduce ripple compensating circuit simultaneously, improve ripple compensating circuit's compensation performance, thereby improve switching power supply's performance.
The above description is only exemplary embodiments of the present application, and is not intended to limit the scope of the present application.
It will be clear to a person skilled in the art that the term user terminal covers any suitable type of wireless user equipment, such as a mobile phone, a portable data processing device, a portable web browser or a car mounted mobile station.
In general, the various embodiments of the application may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the application is not limited thereto.
Embodiments of the application may be implemented by a data processor of a mobile device executing computer program instructions, for example in a processor entity, or by hardware, or by a combination of software and hardware. The computer program instructions may be assembly instructions, Instruction Set Architecture (ISA) instructions, machine related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages.
Any logic flow block diagrams in the figures of this application may represent program steps, or may represent interconnected logic circuits, modules, and functions, or may represent a combination of program steps and logic circuits, modules, and functions. The computer program may be stored on a memory. The memory may be of any type suitable to the local technical environment and may be implemented using any suitable data storage technology, such as, but not limited to, Read Only Memory (ROM), Random Access Memory (RAM), optical storage devices and systems (digital versatile disks, DVDs, or CD discs), etc. The computer readable medium may include a non-transitory storage medium. The data processor may be of any type suitable to the local technical environment, such as but not limited to general purpose computers, special purpose computers, microprocessors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), programmable logic devices (FGPAs), and processors based on a multi-core processor architecture.
The foregoing has provided by way of exemplary and non-limiting examples a detailed description of exemplary embodiments of the present application. Various modifications and adaptations to the foregoing embodiments may become apparent to those skilled in the relevant arts in view of the following drawings and the appended claims without departing from the scope of the invention. Therefore, the proper scope of the invention is to be determined according to the claims.
Claims (15)
1. A ripple compensation circuit, which is built in a switching power supply circuit, includes: the device comprises an output alternating current signal response module, a load direct current signal response module and an adder;
the output alternating current signal response module is respectively connected with the switching end of the switching power supply circuit and the first input end of the adder, and is used for generating a target alternating current voltage and transmitting the target alternating current voltage to the adder, wherein the variation trend of the target alternating current voltage is the same as that of the inductive current;
the load direct current signal response module is respectively connected with the input end of the load circuit and the second input end of the adder, and is used for generating a target direct current voltage and transmitting the target direct current voltage to the adder, wherein the variation trend of the target direct current voltage is the same as that of the output signal;
the output end of the adder is connected with the control end of the switching power supply circuit and used for superposing the target alternating-current voltage and the target direct-current voltage to obtain ripple compensation voltage and feeding the ripple compensation voltage back to the control end, and the ripple compensation voltage is used for feeding the information of the inductive current and the information of the output signal back to the switching power supply circuit so as to keep the output signal constant;
the switch power supply circuit is used for providing the output signal for the load circuit, and the inductor is configured between the switch end of the switch power supply circuit and the input end of the load circuit, and is used for filtering an initial signal output by the switch end of the switch power supply circuit to obtain the output signal and sending the output signal to the input end of the load circuit.
2. The circuit of claim 1, wherein the output ac signal response module comprises: an integrating circuit and an AC coupling circuit;
the integration circuit is used for integrating the initial signal to obtain an integration voltage, and the variation trend of the integration voltage is the same as that of the inductive current;
the alternating current coupling circuit is used for extracting an alternating current component from the integrated voltage to serve as the target alternating current voltage and is coupled into the adder.
3. The circuit of claim 2, wherein the integration circuit comprises a first resistor and a first capacitor, the first resistor and the first capacitor together forming a series circuit to integrate the output voltage;
the first end of the first resistor is connected with the switch end of the switch power supply circuit, and the second end of the first resistor is connected with the first end of the first capacitor;
the second end of the first capacitor is connected with a direct current signal end, and the voltage of the direct current signal end is direct current voltage.
4. A circuit as claimed in claim 3, wherein the ac coupling circuit comprises a second capacitor having a first terminal connected to the first terminal of the first capacitor and a second terminal connected to the first input terminal of the adder.
5. The circuit of claim 4, wherein the load DC signal response module comprises: the voltage division circuit and the direct current coupling circuit;
the voltage division circuit is used for dividing the output voltage corresponding to the output signal to generate a target direct-current voltage;
the direct current coupling circuit is used for coupling the transient change of the target direct current voltage into the adder.
6. The circuit of claim 5, wherein the voltage divider circuit comprises a second resistor and a third resistor; the second resistor and the third resistor jointly form a series circuit to divide the output voltage;
the first end of the second resistor is connected with the second end of the inductor, the second end of the second resistor is respectively connected with the first end of the third resistor and the second input end of the adder, and the voltage at the two ends of the third resistor is the target direct-current voltage;
and the second end of the third resistor is grounded.
7. The circuit of claim 6, wherein the DC coupling circuit comprises a third capacitor; the third capacitor is connected with the second resistor in parallel.
8. The circuit of claim 7, wherein the adder is a P-type metal oxide semiconductor field effect transistor (PMOS), a source of the PMOS serves as a first input terminal of the adder, a gate of the PMOS serves as a second input terminal of the adder, a source of the PMOS serves as an output terminal of the adder, and a drain of the PMOS is grounded.
9. The circuit of claim 1, wherein the switching power supply circuit is a dc-dc converter circuit based on-time control.
10. The circuit of claim 3, wherein the DC signal terminal comprises ground or a second terminal of the second resistor.
11. A ripple compensation method applied to the ripple compensation circuit according to any one of claims 1 to 10, comprising:
generating a target alternating-current voltage through an output alternating-current signal response module, and transmitting the target alternating-current voltage to the adder, wherein the variation trend of the target alternating-current voltage is the same as that of the inductive current;
generating a target direct-current voltage through a load direct-current signal response module, and transmitting the target direct-current voltage to the adder, wherein the variation trend of the target direct-current voltage is the same as that of the output signal;
superposing the target alternating-current voltage and the target direct-current voltage through an output end of an adder to obtain ripple compensation voltage, and feeding the ripple compensation voltage back to a control end of the switching power supply circuit, wherein the ripple compensation voltage is used for feeding back information of the inductive current and information of the output signal to the switching power supply circuit so as to make the output signal constant;
the switch power supply circuit is used for providing the output signal for the load circuit, and the inductor is configured between the switch end of the switch power supply circuit and the input end of the load circuit, and is used for filtering an initial signal output by the switch end of the switch power supply circuit to obtain the output signal and sending the output signal to the input end of the load circuit.
12. A switching power supply circuit, comprising: the ripple compensation circuit of any one of claims 1 to 10, a feedback control circuit, a constant on-time control circuit, a flip-flop, a driver circuit, a PMOS, and an NMOS,
the ripple compensation circuit is respectively connected with the switching end of the switching power supply circuit and the feedback control circuit and is used for generating ripple compensation voltage, and the ripple compensation voltage comprises information of inductive current and information of output signals;
the feedback control circuit is respectively connected with the input end of the switching power supply circuit, the feedback end of the switching power supply circuit and the first input end of the trigger, and is used for generating a feedback control signal according to the received feedback voltage and the ripple compensation voltage, wherein the feedback voltage is obtained by dividing the output voltage;
the output end of the constant on-time control circuit is connected with the second input end of the trigger and used for generating an on-time control signal;
the output end of the trigger is connected with the input end of the driving circuit and used for generating a driving signal according to the conduction time control signal and the feedback control signal;
the first output end of the driving circuit is connected with the grid electrode of the PMOS, the second output end of the driving circuit is connected with the grid electrode of the NMOS, and the driving circuit is used for controlling the connection and disconnection of the PMOS and the NMOS respectively based on the driving signal;
the source electrode of the PMOS is connected with the input end of the switch power supply circuit, the drain electrode of the PMOS is respectively connected with the drain electrode of the NMOS and the switch end of the switch power supply circuit, the source electrode of the NMOS is grounded, and the PMOS and the NMOS are used for jointly cooperating to control the rise and fall of the output voltage of the switch power supply circuit so as to ensure that the switching frequency of the switch power supply circuit is constant.
13. The circuit of claim 12, wherein the feedback control circuit comprises: an error amplifier, a reference circuit and a comparator;
the input end of the reference circuit is connected with the input end of the switching power supply circuit, the output end of the reference circuit is connected with the non-inverting input end of the error amplifier, and the reference circuit is used for generating reference voltage according to the received input voltage provided by the input end of the switching power supply circuit;
the inverting input end of the error amplifier is connected with the feedback end of the switching power supply circuit, the output end of the error amplifier is connected with the non-inverting input end of the comparator, the error amplifier is used for receiving the feedback voltage, amplifying the difference value between the feedback voltage and the reference voltage and outputting an error amplification voltage, and the voltage value of the reference voltage is the same as that of the stabilized feedback voltage;
and the inverting input end of the comparator is connected with the output end of an adder in the ripple compensation circuit, and the output end of the comparator is connected with the first input end of the trigger and used for comparing the ripple compensation voltage with the error amplification voltage and outputting the feedback control signal.
14. The circuit of claim 12, wherein the driver circuit is further configured to increase a dead time between the PMOS turn-on signal and the turn-on signal controlling the NMOS to achieve one number of MOS turned on at the same time.
15. A conduction time control method applied to the switching power supply circuit according to any one of claims 11 to 13, comprising:
generating ripple compensation voltage through a ripple compensation circuit, wherein the ripple compensation voltage comprises information of inductive current and information of output signals;
generating a feedback control signal according to the received feedback voltage and the ripple compensation voltage through a feedback control circuit, wherein the feedback voltage is obtained by dividing the output voltage;
generating an on-time control signal through a constant on-time control circuit;
generating a driving signal according to the on-time control signal and the feedback control signal through a trigger;
respectively controlling the on-off of the PMOS and the NMOS based on the driving signal through a driving circuit;
the PMOS is combined with the NMOS to cooperatively control the rise and fall of the output voltage of the switching power supply circuit so as to ensure that the switching frequency of the switching power supply circuit is constant.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112688559A (en) * | 2020-12-17 | 2021-04-20 | 南京天之立科技有限公司 | Switching power supply circuit |
| CN114430227A (en) * | 2022-02-07 | 2022-05-03 | Oppo广东移动通信有限公司 | Ripple voltage processing device and method and switching power supply |
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2019
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112688559A (en) * | 2020-12-17 | 2021-04-20 | 南京天之立科技有限公司 | Switching power supply circuit |
| CN114430227A (en) * | 2022-02-07 | 2022-05-03 | Oppo广东移动通信有限公司 | Ripple voltage processing device and method and switching power supply |
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