BOOST circuit with overcurrent protection, overcurrent protection method and voltage booster

Abstract

The invention relates to a BOOST circuit with overcurrent protection, an overcurrent protection method and a booster. The BOOST circuit comprises a switching circuit, a first switching circuit and a second switching circuit, the in-phase input end of the differential amplification circuit is used for obtaining a reference voltage signal, the inverted input end of the differential amplification circuit is used for obtaining a feedback signal, and the feedback signal is obtained based on an output voltage signal of the BOOST circuit; the first output end of the differential amplification circuit is used for outputting a working mode signal, and the working mode signal represents the current load state of the BOOST circuit; the over-current protection circuit is used for outputting a first enable signal according to the detected inductance voltage signal flowing into the switching circuit and the working mode signal under the condition that the switching circuit acts; the first enable signal is used for enabling the differential amplification circuit. According to the BOOST circuit, the overall power consumption of the BOOST circuit can be reduced, and the working efficiency of the BOOST circuit is effectively improved.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and particularly to a BOOST circuit with overcurrent protection, an overcurrent protection method, and a booster. Background Art

[0002] The BOOST circuit is applied to scenarios such as electric vehicle charging systems, uninterruptible power supply systems, and solar power generation systems. Its main function is to convert an input voltage signal into a higher-output voltage signal, that is, to boost the input signal. When the BOOST circuit is working, a large current may occur and cause damage to the circuit. Based on this, it is often necessary to set a corresponding overcurrent protection circuit for the BOOST circuit.

[0003] However, the traditional overcurrent protection circuit needs to continuously monitor the working state of the BOOST circuit. This protection method will increase the overall power consumption of the circuit system and also affect the working efficiency of the BOOST circuit. Summary of the Invention

[0004] Based on this, in view of the above technical problems, it is necessary to provide a BOOST circuit with overcurrent protection, an overcurrent protection method, and a booster that can achieve overcurrent protection with low power consumption.

[0005] In a first aspect, in one embodiment, the present application provides a BOOST circuit with overcurrent protection, including:

[0006] A switching circuit;

[0007] A differential amplifier circuit. The non-inverting input terminal of the differential amplifier circuit is used to obtain a reference voltage signal, and the inverting input terminal of the differential amplifier circuit is used to obtain a feedback signal. The feedback signal is obtained based on the output voltage signal of the BOOST circuit. The first output terminal of the differential amplifier circuit is used to output a working mode signal, and the working mode signal characterizes the current load state of the BOOST circuit; and,

[0008] An overcurrent protection circuit. The overcurrent protection circuit is used to output a first enable signal according to the detected inductance voltage signal flowing into the switching circuit and the working mode signal when the switching circuit operates; the first enable signal is used to enable the differential amplifier circuit.

[0009] In one of the embodiments, the BOOST circuit further includes:

[0010] A first comparator. The non-inverting input terminal of the first comparator is connected to one end of the switching circuit, and the inverting input terminal of the first comparator is connected to the second output terminal of the differential amplifier circuit;

[0011] A control logic circuit, the first input terminal of the control logic circuit is connected to the output terminal of the first comparator, the second input terminal of the control logic circuit is used to be connected to an oscillator, and the output terminal of the control logic circuit is connected to the control terminal of the switching circuit;

[0012] Among them, the output terminal of the control logic circuit is used to output a first switching signal to determine the operation of the switching circuit; the first enable signal is also used to enable the first comparator and the control logic circuit.

[0013] In one embodiment, the oscillator is used to output a periodic oscillation signal to the control logic circuit; the output terminal of the first comparator is used to output a mode selection signal; the first enable signal is also used to enable the oscillator;

[0014] If the oscillation signal input to the control logic circuit is a rising edge signal, the first switching signal output by the control logic circuit controls the switching circuit to conduct;

[0015] If the mode selection signal input to the control logic circuit is a rising edge signal, the first switching signal output by the control logic circuit controls the switching circuit to cut off.

[0016] In one embodiment, the BOOST circuit further includes:

[0017] An inductor unit, one end of the inductor unit is used to obtain the input voltage signal of the BOOST circuit, and the other end of the inductor unit is connected to the other end of the switching circuit;

[0018] A diode unit, the positive electrode of the diode unit is connected between the other end of the inductor unit and the other end of the switching circuit;

[0019] A capacitor unit, one end of the capacitor unit is connected to the negative electrode of the diode unit, and the other end of the capacitor unit is used to be grounded.

[0020] In one embodiment, the switching circuit includes:

[0021] A first switching transistor, one end of the first switching transistor is connected between the other end of the inductor unit and the positive electrode of the diode unit, and the control terminal of the first switching transistor is connected to the output terminal of the control logic circuit to obtain the first switching signal;

[0022] A second switching transistor, one end of the second switching transistor is connected between the one end of the first switching transistor and the positive electrode of the diode unit, and the control terminal of the second switching transistor is connected to the output terminal of the control logic circuit to obtain the first switching signal;

[0023] A second comparator, the non-inverting input terminal of the second comparator is connected to the other end of the first switching transistor, the inverting input terminal of the second comparator is connected to the other end of the second switching transistor, and the output terminal of the second comparator is connected to the non-inverting input terminal of the first comparator;

[0024] The first resistor, one end of the first resistor is connected between the non-inverting input terminal of the second comparator and the other end of the first switching transistor, and the other end of the first resistor is connected between the inverting input terminal of the second comparator and the other end of the second switching transistor. The other end of the first resistor is also used for grounding;

[0025] The second resistor, one end of the second resistor is connected between the non-inverting input terminal of the first comparator and the output terminal of the second comparator, and the other end of the second resistor is used for grounding;

[0026] Wherein, the first enable signal is also used to enable the second comparator.

[0027] In one embodiment, the size of the first switching transistor and the size of the second switching transistor are in a preset proportional relationship.

[0028] In one embodiment, the BOOST circuit further includes:

[0029] The first voltage dividing resistor, one end of the first voltage dividing resistor is used to obtain the output voltage signal, and the other end of the first voltage dividing resistor is connected to the inverting input terminal of the differential amplifier circuit;

[0030] The second voltage dividing resistor, one end of the second voltage dividing resistor is connected between the other end of the first voltage dividing resistor and the inverting input terminal of the differential amplifier circuit, and the other end of the second voltage dividing resistor is used for grounding;

[0031] Wherein, the feedback signal is the voltage signal after the output voltage signal is divided by the first voltage dividing resistor and the second voltage dividing resistor.

[0032] In one embodiment, the overcurrent protection circuit includes:

[0033] The third comparator, the non-inverting input terminal of the third comparator is used to connect to the constant current source, and the enable terminal of the third comparator is used to obtain the second enable signal;

[0034] The third switching transistor, one end of the third switching transistor is connected to the inverting input terminal of the third comparator, the other end of the third switching transistor is used for grounding, and the control terminal of the third switching transistor is used to obtain the second switching signal, and the second switching signal is the inverted signal of the first switching signal;

[0035] The fourth switching transistor, one end of the fourth switching transistor is used to obtain the inductor voltage signal, the other end of the fourth switching transistor is connected between one end of the third switching transistor and the inverting input terminal of the third comparator, and the control terminal of the fourth switching transistor is used to obtain the third switching signal, and the third switching signal is the inverted signal of the second switching signal;

[0036] The fifth switching transistor, one end of the fifth switching transistor is connected between the constant current source and the non-inverting input terminal of the third comparator, the other end of the fifth switching transistor is used for grounding, and the control terminal of the fifth switching transistor is used to obtain the second enable signal;

[0037] Wherein, the second enabling signal is obtained based on the working mode signal and the third switching signal.

[0038] In one embodiment, the overcurrent protection circuit further includes:

[0039] A first NOT gate circuit, the input end of the first NOT gate circuit is used to obtain the working mode signal;

[0040] A first AND gate circuit, the first input end of the first AND gate circuit is connected to the output end of the first NOT gate circuit, and the second input end of the first AND gate circuit is used to obtain the third switching signal;

[0041] Wherein, the output end of the first AND gate circuit outputs the second enabling signal.

[0042] In one embodiment, the third input end of the first AND gate circuit is used to obtain the system enabling signal;

[0043] Wherein, the system enabling signal is used to enable the BOOST circuit.

[0044] In one embodiment, the overcurrent protection circuit further includes:

[0045] A second AND gate circuit, the first input end of the second AND gate circuit is used to obtain the system enabling signal, and the second input end of the second AND gate circuit is connected to the output end of the third comparator;

[0046] Wherein, the output end of the second AND gate circuit is used to output the first enabling signal.

[0047] In one embodiment, when the differential amplification signal of the differential amplification circuit is greater than or equal to the preset voltage threshold, the working mode signal output by the differential amplification circuit is a low-level signal; the differential amplification signal is obtained based on the feedback signal and the reference voltage signal;

[0048] When the differential amplification signal is less than the preset voltage threshold, the working mode signal output by the differential amplification circuit is a periodic square wave signal.

[0049] In a second aspect, in one embodiment, the present application provides an overcurrent protection method, which is applied to the BOOST circuit with overcurrent protection as described in any one of the above embodiments; the method includes:

[0050] If it is determined according to the output voltage signal that the BOOST circuit is in a heavy load state, the overcurrent protection circuit is turned on in the charging stage and turned off in the freewheeling stage;

[0051] If it is determined that the BOOST circuit is in a light load state based on the output voltage signal, the operating state of the overcurrent protection circuit changes with the periodic operating mode signal: when the periodic operating mode signal is at a low level, the overcurrent protection circuit is turned on during the charging stage and turned off during the freewheeling stage; when the periodic operating mode signal is at a high level, the overcurrent protection circuit is turned off.

[0052] In a third aspect, in one embodiment, the present application provides a booster, including a BOOST circuit with overcurrent protection as described in any one of the above embodiments.

[0053] The above BOOST circuit with overcurrent protection, overcurrent protection method, and booster realize the charging and discharging of the inductor of the BOOST circuit by controlling the on and off of the switch circuit, and also realize the determination of the current load state of the BOOST circuit according to the output voltage signal through a differential amplifier circuit, and then determine the operating state of the overcurrent protection circuit according to the load state and operating stage of the BOOST circuit. In the above manner, the present application can enable the overcurrent protection circuit to enter different operating states according to different load states and operating stages of the BOOST circuit, so that the overcurrent protection function does not have to be always enabled during the operation of the BOOST circuit, reducing the overall power consumption of the BOOST circuit and effectively improving the operating efficiency of the BOOST circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the drawings required for use in the description of the embodiments of the present application or related technologies. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0055] Figure 1 It is a schematic diagram of the basic circuit structure of the BOOST circuit in one embodiment;

[0056] Figure 2 It is a schematic diagram of the circuit structure of the BOOST circuit with overcurrent protection in one embodiment;

[0057] Figure 3 It is a schematic diagram of the input and output signals of the overcurrent protection circuit in one embodiment;

[0058] Figure 4 It is a schematic diagram of the signals of the differential amplifier circuit in one embodiment;

[0059] Figure 5 It is a schematic diagram of the circuit structure of the BOOST circuit with overcurrent protection in another embodiment;

[0060] Figure 6 It is a voltage waveform diagram of a BOOST circuit in an embodiment;

[0061] Figure 7 It is a schematic diagram of the circuit structure of a BOOST circuit with over - current protection in another embodiment;

[0062] Figure 8 It is a signal schematic diagram of a differential amplifier circuit in another embodiment;

[0063] Figure 9 It is a partial schematic diagram of the structure of an over - current protection circuit in an embodiment;

[0064] Figure 10 It is a schematic diagram of the relationship between various switching signals in an embodiment;

[0065] Figure 11 It is a partial schematic diagram of the structure of an over - current protection circuit in another embodiment;

[0066] Figure 12 It is a partial schematic diagram of the structure of an over - current protection circuit in yet another embodiment;

[0067] Figure 13 It is a partial schematic diagram of the structure of an over - current protection circuit in still another embodiment;

[0068] Figure 14 It is a voltage waveform diagram of a BOOST circuit in a heavy - load state in an embodiment;

[0069] Figure 15 It is a voltage waveform diagram of a BOOST circuit in a light - load state in an embodiment;

[0070] Figure 16 It is a flowchart of an over - current protection method in an embodiment. Detailed implementation manners

[0071] In order to make the purpose, technical solutions and advantages of this application clearer, the following further elaborates on this application in combination with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0072] It can be understood that the terms "first", "second", etc. used in this application can be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the scope of this application, the first resistor can be called the second resistor, and similarly, the second resistor can be called the first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0073] It can be understood that for the "connection" in the following embodiments, if there is transmission of electrical signals or data between the connected circuits, modules, units, etc., it should be understood as "electrical connection", "communication connection", etc.

[0074] It can be understood that "at least one" means one or more, and "a plurality" means two or more. "At least a part of an element" means part or all of the element.

[0075] As used herein, the singular forms "a", "an" and "the" may also include the plural forms unless the context clearly dictates otherwise. It should also be understood that the terms "comprises / include" or "has" etc. specify the presence of the stated features, wholes, steps, operations, components, parts or combinations thereof, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the related listed items.

[0076] BOOST circuits are often required in occasions such as electric vehicle charging systems, uninterruptible power supply systems, solar power generation systems, etc. As Figure 1 shown, the basic circuit structure of a BOOST circuit may include an inductor unit L, a switch unit S, a diode unit D, and a capacitor unit CL. It is mainly used to raise the input voltage VIN of the circuit to an output voltage VOUT higher than the input voltage. That is, through the operation of the inductor unit L and the switch unit S, the BOOST circuit can achieve the function of boosting the input voltage VIN. It can be understood that the above switch unit can be either a single switch element or a switch circuit composed of multiple switch elements (such as switching transistors) in combination with other circuit elements (such as current comparators, etc.).

[0077] BOOST circuits have the advantages of high conversion efficiency, wide voltage regulation range, and the ability to output large currents. However, the peripheral circuits of BOOST circuits are often relatively complex, and the output ripple is relatively large. There may be an abnormally large current resulting in circuit damage. Therefore, it is necessary to set a corresponding overcurrent protection mechanism in the BOOST to achieve circuit protection.

[0078] Traditional overcurrent protection circuits applied to BOOST circuits often need to always maintain the activation of their overcurrent protection functions to achieve circuit protection. However, this method actually affects the operating efficiency of the BOOST and increases the overall power consumption of the circuit.

[0079] To solve the above problems, in one embodiment, as Figures 2 to 4 shown, the present application provides a BOOST circuit 200 with overcurrent protection. The BOOST circuit includes:

[0080] Switching circuit 202;

[0081] Differential amplifier circuit EA. The non-inverting input terminal of the differential amplifier circuit EA is used to obtain a reference voltage signal VREF, and the inverting input terminal of the differential amplifier circuit EA is used to obtain a feedback signal VFB. The feedback signal VFB is obtained based on the output voltage signal of the BOOST circuit 200. The first output terminal of the differential amplifier circuit EA is used to output a working mode signal BURST_EN, and the working mode signal BURST_EN characterizes the current load state of the BOOST circuit 200. And,

[0082] Overcurrent protection circuit OCP. The overcurrent protection circuit OCP is used to output a first enable signal EN according to the detected inductor voltage signal VSW flowing into the switching circuit 202 and the working mode signal BURST_EN when the switching circuit 202 operates. The first enable signal EN is used to enable the differential amplifier circuit EA.

[0083] Among them, the switching circuit 202 can be used to charge the inductor unit L of the BOOST circuit 200 when it is turned on, and discharge the inductor unit L of the BOOST circuit 200 when it is turned off. In some examples, when the inductor unit L is charging, the BOOST circuit 200 is regarded as entering the charging stage; when the inductor unit L is discharging, the BOOST circuit 200 enters the freewheeling stage. Figure 2 The shown PGND and VSS both represent circuit ground.

[0084] It can be understood that the switching circuit 202 can be composed of one or more switching tubes, current comparators and other circuit elements. The specific structure of the switching circuit 202 can be determined according to actual application requirements, as long as it can realize the functions of line conduction and cut-off. The embodiments of the present application do not specifically limit the specific structure of the switching circuit 202. It should be noted that when the specific structure of the switching circuit 202 includes elements such as a current comparator, the overcurrent protection circuit OCP can also enable elements such as the current comparator in the switching circuit 202 through the first enable signal EN.

[0085] Exemplarily, as shown in the following formula 1, when the differential amplifier circuit EA operates, it can output a corresponding differential amplification signal at the second output terminal of the differential amplifier circuit EA according to the reference voltage signal VREF at the non-inverting input terminal and the feedback signal VFB at the inverting input terminal:

[0086] VD = A * (VREF - VFB) (Formula 1)

[0087] Wherein, VD is the differential amplification signal output by the differential amplification circuit EA, A is the gain of the differential amplification circuit EA, VREF is the reference voltage signal VREF, and VFB is the feedback signal VFB. Optionally, the feedback signal VFB can be obtained by voltage division processing of the output voltage signal of the BOOST circuit 200.

[0088] In some examples, when the differential amplification signal VD exceeds a preset voltage threshold, the differential amplification circuit EA determines that the current load state of the BOOST circuit 200 is in a heavy load state; when the differential amplification signal does not exceed the preset voltage threshold, the differential amplification circuit EA determines that the current load state of the BOOST circuit 200 is in a light load state.

[0089] Furthermore, the operation mode signal BURST_EN includes a heavy load mode signal and a light load mode signal; wherein, the heavy load mode signal indicates that the current BOOST circuit 200 is in a heavy load state, and the light load mode signal indicates that the current BOOST circuit 200 is in a light load state. It can be understood that if it is determined according to the differential amplification signal that the current BOOST circuit 200 is in a heavy load state, the differential amplification circuit EA outputs the heavy load mode signal from the first output terminal; if it is determined according to the differential amplification signal that the current BOOST circuit 200 is in a light load state, the differential amplification circuit EA outputs the light load mode signal from the first output terminal. Optionally, the heavy load mode signal can be a low-level signal, and the light load mode signal can be a periodically changing logic level signal.

[0090] Exemplarily, the overcurrent protection circuit OCP can stop the operation of the BOOST circuit 200 when the inductor current IL and / or the inductor voltage signal VSW of the BOOST circuit 200 exceed a set threshold; wherein, the inductor current IL is the current value of the inductor unit L of the BOOST circuit 200. For example, when the inductor current IL of the BOOST circuit 200 is greater than a preset current threshold, it can be determined that the current BOOST circuit 200 has an overcurrent phenomenon. At this time, the overcurrent protection circuit OCP will disable circuit modules such as the differential amplification circuit EA to stop the operation of the BOOST circuit 200, thereby preventing various components of the BOOST circuit 200 from being damaged by abnormal current.

[0091] In some examples, the specific structure of the switch circuit 202 includes circuit elements such as a current comparator. When the BOOST circuit 200 has an overcurrent, the overcurrent protection circuit OCP can also disable these circuit elements to achieve circuit protection, which will not be elaborated here.

[0092] Further, the overcurrent protection circuit OCP can determine the current operation of the switch circuit 202 according to the first switch signal NDR that controls the conduction or cutoff of the switch circuit 202. When the switch circuit 202 is operating, the overcurrent protection circuit OCP can determine the current operation stage and load state of the current BOOST circuit 200 according to the detected inductor voltage signal VSW flowing into the switch circuit 202 and the operation mode signal BURST_EN, and determine the current working state of the overcurrent protection circuit OCP according to the operation stage and load state of BOOST.

[0093] In some possible implementations, when it is determined according to the operation mode signal BURST_EN that the BOOST circuit 200 is currently in a heavy load state, the overcurrent protection circuit OCP can be turned on during the charging stage of the BOOST circuit 200 and turned off during the freewheeling stage of the BOOST circuit 200; when it is determined according to the operation mode signal BURST_EN that the BOOST circuit 200 is in a light load state, the working state of the overcurrent protection circuit OCP will perform a state transition along with the operation mode signal BURST_EN whose level changes periodically between high and low. For example, when the periodic operation mode signal BURST_EN is currently at a low level, the overcurrent protection circuit OCP is turned on during the charging stage and turned off during the freewheeling stage (the same as in the heavy load case); when the periodic operation mode signal BURST_EN is currently at a high level, the overcurrent protection circuit OCP is turned off.

[0094] It can be understood that overcurrent faults in the BOOST circuit 200 usually occur during the charging stage in the heavy load state. Through the above method, the BOOST circuit 200 in the embodiment of the present application can adaptively enable the overcurrent protection circuit OCP according to the current operation stage and load state, thereby avoiding energy waste caused by always turning on the overcurrent protection function, reducing the overall power consumption of the BOOST circuit 200, and improving the working efficiency of the BOOST circuit 200.

[0095] The above BOOST circuit with overcurrent protection realizes the charging and discharging of the inductor of the BOOST circuit by controlling the conduction and cutoff of the switch circuit, and realizes the determination of the current load state of the BOOST circuit according to the output voltage signal through the differential amplifier circuit, and then adjusts the working state of the overcurrent protection circuit according to the load state and operation stage of the BOOST circuit, so that the BOOST circuit can realize the adaptive enabling of the overcurrent protection function, thereby reducing the overall power consumption of the BOOST circuit and effectively improving the working efficiency of the BOOST circuit.

[0096] In one of the embodiments, as Figure 5 shown, the BOOST circuit 200 further includes:

[0097] The first comparator COMP1, the non-inverting input terminal of the first comparator COMP1 is connected to one end of the switch circuit 202, and the inverting input terminal of the first comparator COMP1 is connected to the second output terminal of the differential amplifier circuit EA;

[0098] The control logic circuit 204, the first input terminal of the control logic circuit 204 is connected to the output terminal of the first comparator COMP1, the second input terminal of the control logic circuit 204 is used to connect to the oscillator OSC, and the output terminal of the control logic circuit 204 is connected to the control terminal of the switch circuit 202;

[0099] Among them, the output terminal of the control logic circuit 204 is used to output the first switching signal NDR to determine the operation of the switch circuit 202; the first enable signal EN is also used to enable the first comparator COMP1 and the control logic circuit 204.

[0100] Exemplarily, the first comparator COMP1 can output a mode selection signal MODE to the control logic circuit 204 according to the inductor current detection signal from the switch circuit 202 and the differential amplification signal from the differential amplifier circuit EA. The control logic circuit 204 can control the working state of the switch circuit 202 according to the received mode selection signal MODE.

[0101] Specifically, when the inductor current detection signal from the switch circuit 202 is greater than the differential amplification signal VD output from the differential amplifier circuit EA, the first comparator COMP1 sends the corresponding mode selection signal MODE to the first input terminal of the control logic circuit 204, and the control logic circuit 204 adjusts the working state of the switch circuit 202 according to the received mode selection signal MODE.

[0102] In one embodiment, the oscillator OSC is used to output a periodic oscillation signal CLK to the control logic circuit 204; the output terminal of the first comparator COMP1 is used to output a mode selection signal; the first enable signal EN is also used to enable the oscillator OSC;

[0103] If the oscillation signal CLK input to the control logic circuit 204 is a rising edge signal, the first switching signal NDR output by the control logic circuit 204 controls the switch circuit 202 to conduct;

[0104] If the mode selection signal input to the control logic circuit 204 is a rising edge signal, the first switching signal NDR output by the control logic circuit 204 controls the switch circuit 202 to cut off.

[0105] Exemplarily, an oscillator OSC (Oscillator) can output a periodically varying square-wave oscillation signal CLK. It can be understood that the oscillator OSC can be either an external oscillation circuit connected to the BOOST circuit or a circuit component built into the BOOST circuit for outputting the oscillation signal CLK. The embodiments of the present application do not make specific limitations in this regard. When the oscillator OSC is built into the BOOST circuit, the overcurrent protection circuit OCP can also enable the built-in oscillator OSC through the first enable signal EN.

[0106] Specifically, as Figure 6 shown, when receiving a rising edge signal from the oscillator OSC, the control logic circuit 204 outputs a high-level first switch signal NDR to the switch circuit 202 to control the switch circuit 202 to conduct through the first switch signal NDR, so that the inductor unit L is charged and the inductor current IL gradually increases, and the BOOST circuit is in the charging stage; when receiving a rising edge signal from the first comparator COMP1, the control logic circuit 204 outputs a low-level first switch signal NDR to the switch circuit 202 to control the switch circuit 202 to cut off through the first switch signal NDR, so that the inductor unit L discharges and the inductor current IL gradually decreases, and the BOOST circuit is in the freewheeling stage.

[0107] In one embodiment, as Figure 2 shown, the BOOST circuit 200 further includes:

[0108] An inductor unit L, one end of the inductor unit L is used to obtain the input voltage signal VIN of the BOOST circuit, and the other end of the inductor unit L is connected to the other end of the switch circuit 202;

[0109] A diode unit D, the positive electrode of the diode unit D is connected between the other end of the inductor unit L and the other end of the switch circuit 202;

[0110] A capacitor unit CL, one end of the capacitor unit CL is connected to the negative electrode of the diode unit D, and the other end of the capacitor unit CL is used to ground.

[0111] In some examples, the inductor unit L can be one or more inductors. When the inductor unit L includes multiple inductors, the inductance value of the entire inductor unit L can be changed by changing the specifications, quantities, and connection relationships of the respective inductors.

[0112] In some possible implementations, the capacitor unit CL can be one or more capacitors. When the capacitor unit CL includes multiple capacitors, the capacitance value of the entire capacitor unit CL can be changed by changing the specifications, quantities, and connection relationships of the respective capacitors.

[0113] In one embodiment, asFigure 7 As shown, the switching circuit 202 includes:

[0114] A first switching transistor MN1, one end of the first switching transistor MN1 is connected between the other end of the inductor unit L and the positive electrode of the diode unit D, and the control end of the first switching transistor MN1 is connected to the output end of the control logic circuit 204 to obtain a first switching signal NDR;

[0115] A second switching transistor MN2, one end of the second switching transistor MN2 is connected between the one end of the first switching transistor MN1 and the positive electrode of the diode unit D, and the control end of the second switching transistor MN2 is connected to the output end of the control logic circuit 204 to obtain a first switching signal NDR;

[0116] A second comparator ICOMP, the non-inverting input terminal of the second comparator ICOMP is connected to the other end of the first switching transistor MN1, the inverting input terminal of the second comparator ICOMP is connected to the other end of the second switching transistor, and the output terminal of the second comparator ICOMP is connected to the non-inverting input terminal of the first comparator COMP1;

[0117] A first resistor R1, one end of the first resistor R1 is connected between the non-inverting input terminal of the second comparator ICOMP and the other end of the first switching transistor MN1, the other end of the first resistor R1 is connected between the inverting input terminal of the second comparator ICOMP and the other end of the second switching transistor MN2, and the other end of the first resistor R1 is also used for grounding;

[0118] A second resistor R2, one end of the second resistor R2 is connected between the non-inverting input terminal of the first comparator COMP1 and the output terminal of the second comparator ICOMP, and the other end of the second resistor R2 is used for grounding;

[0119] Wherein, the first enable signal EN is also used to enable the second comparator ICOMP.

[0120] Specifically, the control logic circuit 204 simultaneously outputs the first switching signal NDR to the control ends of the first switching transistor MN1 and the second switching transistor MN2, so that the first switching transistor MN1 and the second switching transistor MN2 are simultaneously turned on or off, and both maintain the same switching state.

[0121] Furthermore, in the above-mentioned switching circuit 202, the branch where the first switching transistor MN1 is located can be used to mirror the current of the branch where the second switching transistor MN2 is located.

[0122] In some examples, the first resistor R1 can be set as a resistor with a relatively small resistance value. After the mirror inductor current flowing out of the first switching transistor MN1 passes through the first resistor R1 with a relatively small resistance value, a relatively small inductor detection voltage VLsense will be generated. Since the inductor detection voltage VLsense is relatively small, the second comparator ICOMP can output a corresponding inductor detection current ILsense based on the inductor detection voltage VLsense. The inductor detection current ILsense can be further used to obtain an inductor current detection signal through the second resistor R2. It can be understood that there is a certain proportional relationship between the above-mentioned inductor detection current ILsense and the inductor current IL of the BOOST circuit, and the inductor current detection signal can be used to characterize the magnitude of the current inductor current IL of the current BOOST circuit. Optionally, the second comparator ICOMP can be a current comparator.

[0123] In one embodiment, the size of the first switching transistor MN1 and the size of the second switching transistor MN2 are in a preset proportional relationship.

[0124] Exemplarily, the above-mentioned size can refer to the aspect ratio of the switching transistor. Optionally, the second switching transistor MN2 can be a power transistor.

[0125] For example, if there is a preset proportional relationship of 1:N between the size of the first switching transistor MN1 and the size of the second switching transistor MN2, since during the charging stage, the current flowing through the second switching transistor MN2 is equal to the inductor current, the current flowing through the first switching transistor MN1 at this time is IL / N.

[0126] In one embodiment, as Figure 8 shown, the BOOST circuit 200 further includes:

[0127] A first voltage-dividing resistor Rf1, one end of the first voltage-dividing resistor Rf1 is used to obtain the output voltage signal VOUT, and the other end of the first voltage-dividing resistor Rf1 is connected to the inverting input terminal of the differential amplifier circuit EA;

[0128] A second voltage-dividing resistor Rf2, one end of the second voltage-dividing resistor Rf2 is connected between the other end of the first voltage-dividing resistor Rf1 and the inverting input terminal of the differential amplifier circuit EA, and the other end of the second voltage-dividing resistor Rf2 is used to ground;

[0129] Wherein, the feedback signal VREF is a voltage signal obtained by voltage-dividing the output voltage signal VOUT through the first voltage-dividing resistor Rf1 and the second voltage-dividing resistor Rf2.

[0130] Specifically, the BOOST circuit can use the first voltage dividing resistor Rf1 and the second voltage dividing resistor Rf2 to divide the output voltage signal VOUT of the BOOST circuit to obtain a feedback signal VREF. After the feedback signal VREF is input into the differential amplifier circuit EA, a feedback loop can be formed.

[0131] In one embodiment, as Figure 9 shown, the overcurrent protection circuit OCP includes:

[0132] A third comparator COMP3, the non-inverting input terminal of the third comparator COMP3 is used to connect to the constant current source Iref, and the enable terminal of the third comparator COMP3 is used to obtain the second enable signal ENOCP;

[0133] A third switching transistor MN3, one end of the third switching transistor MN3 is connected to the inverting input terminal of the third comparator COMP3, the other end of the third switching transistor MN3 is used to ground, and the control terminal of the third switching transistor MN3 is used to obtain the second switching signal NDR_N, and the second switching signal NDR_N is the inverted signal of the first switching signal NDR;

[0134] A fourth switching transistor MN4, one end of the fourth switching transistor MN4 is used to obtain the inductor voltage signal VSW, the other end of the fourth switching transistor MN4 is connected between one end of the third switching transistor MN3 and the inverting input terminal of the third comparator COMP3, and the control terminal of the fourth switching transistor MN4 is used to obtain the third switching signal NDR_NN, and the third switching signal NDR_NN is the inverted signal of the second switching signal NDR_N;

[0135] A fifth switching transistor MN5, one end of the fifth switching transistor MN5 is connected between the constant current source Iref and the non-inverting input terminal of the third comparator COMP3, the other end of the fifth switching transistor MN5 is used to ground, and the control terminal of the fifth switching transistor MN5 is used to obtain the second enable signal ENOCP;

[0136] Wherein, the second enable signal ENOCP is obtained based on the working mode signal BURST_EN and the third switching signal NDR_NN.

[0137] Exemplarily, the relationship among the first switching signal NDR, the second switching signal NDR_N, and the third switching signal NDR_NN is as Figure 10 shown. It can be understood that the control logic circuit 204 outputs the first switching signal NDR, the second switching signal NDR_N is the inverted signal of the first switching signal NDR, and the third switching signal NDR_NN is the inverted signal of the second switching signal NDR_N. The above inverted signals can be obtained through a NOT gate circuit as Figure 10 shown.

[0138] Specifically, the third comparator COMP3 of the overcurrent protection circuit OCP can determine whether there is an overcurrent fault in the current BOOST circuit according to the input signal. In some examples, in the case of an overcurrent fault in the BOOST circuit, the third comparator COMP3 can output an overcurrent judgment signal OCP_OUT with a low level. When the overcurrent judgment signal OCP_OUT is at a low level, the first enable signal EN disables various circuit modules of the BOOST circuit, thereby preventing circuit components from being damaged by abnormal current.

[0139] In one embodiment, as Figure 11 shown, the overcurrent protection circuit OCP further includes:

[0140] A first NOT gate circuit 208, the input end of the first NOT gate circuit 208 is used to obtain the operating mode signal BURST_EN;

[0141] A first AND gate circuit 210, the first input end of the first AND gate circuit 210 is connected to the output end of the first NOT gate circuit 208, and the second input end of the first AND gate circuit 210 is used to obtain the third switch signal NDR_NN;

[0142] Wherein, the output end of the first AND gate circuit 210 outputs a second enable signal ENOCP.

[0143] Specifically, the overcurrent protection circuit OCP can determine the signal type of the second enable signal ENOCP according to the third switch signal NDR_NN and the inverted signal of the operating mode signal BURST_EN, so as to realize the control of the fifth switching transistor MN5 and the third comparator COMP3.

[0144] In one embodiment, as Figure 12 shown, the third input end of the first AND gate circuit 210 is used to obtain the system enable signal ENBOOST;

[0145] Wherein, the system enable signal ENBOOST is used to enable the BOOST circuit.

[0146] Specifically, if the system enable signal ENBOOST is at a high level, indicating that the current BOOST circuit is working, the first AND gate circuit 210 needs to determine the signal type of the output second enable signal ENOCP according to the third switch signal NDR_NN and the inverted signal of the operating mode signal BURST_EN; if the system enable signal ENBOOST is at a low level, indicating that the entire BOOST circuit needs to be turned off currently, the first AND gate circuit 210 outputs a second enable signal ENOCP with a low level to control the fifth switching transistor MN5 to turn off and disable the third comparator COMP3.

[0147] In one embodiment, asFigure 13 As shown, the overcurrent protection circuit OCP further includes:

[0148] A second AND gate circuit 212, the first input terminal of the second AND gate circuit 212 is used to obtain the system enable signal ENBOOST, and the second input terminal of the second AND gate circuit 212 is connected to the output terminal of the third comparator COMP3;

[0149] Wherein, the output terminal of the second AND gate circuit 212 is used to output the first enable signal EN.

[0150] Specifically, if the system enable signal ENBOOST is at a high level, indicating that the current BOOST circuit is working, the second AND gate circuit 212 determines the signal type of the first enable signal EN according to the overcurrent judgment signal OCP_OUT of the third comparator COMP3, thereby realizing overcurrent protection; if the system enable signal ENBOOST is at a high level, indicating that the entire BOOST circuit needs to be turned off currently, the second AND gate circuit 212 outputs the first enable signal EN at a low level, disabling all circuit modules controlled by the first enable signal EN.

[0151] In one embodiment, when the differential amplification signal VD of the differential amplification circuit EA is greater than or equal to the preset voltage threshold, the operating mode signal BURST_EN output by the differential amplification circuit EA is a low-level signal; the differential amplification signal VD is obtained based on the feedback signal VFB and the reference voltage signal VREF;

[0152] When the differential amplification signal VD is less than the preset voltage threshold, the operating mode signal BURST_EN output by the differential amplification circuit EA is a periodic square wave signal.

[0153] Specifically, as Figure 14 shown, Figure 14 is the voltage waveform diagram of the BOOST circuit when there is no overcurrent fault in the heavy load state. When the differential amplification signal VD of the differential amplification circuit EA is greater than or equal to the preset voltage threshold, it indicates that the current BOOST circuit is in the heavy load state, and the differential amplification circuit EA outputs the operating mode signal BURST_EN at a low level. At this time, the second enable signal ENOCP is affected by the first switch signal NDR output by the control logic circuit 204. The third comparator COMP3 of the overcurrent protection circuit OCP can be normally enabled when the inductor unit L is charging (that is, the charging stage when the inductor current IL increases), and will be disabled when the inductor unit L is discharging (that is, the freewheeling stage when the inductor current IL decreases). That is, in the heavy load state, the overcurrent protection circuit OCP will be turned on during the charging stage of the BOOST circuit and turned off during the freewheeling stage of the BOOST circuit.

[0154] Furthermore, as Figure 15 shown,Figure 15 It is a voltage waveform diagram of the BOOST circuit in the light load state. When the differential amplification signal VD of the differential amplification circuit EA is less than the preset voltage threshold, it indicates that the current BOOST circuit is in the light load state, and the working mode signal BURST_EN output by the differential amplification circuit EA is a square wave signal with periodically changing levels. It can be understood that in the case where the current BOOST circuit is in the light load state, when the working mode signal BURST_EN is a low-level signal, the second enable signal ENOCP is affected by the first switch signal NDR output by the control logic circuit 204, and the third comparator COMP3 of the overcurrent protection circuit OCP can be normally enabled when the inductor unit L is charging and will be disabled when the inductor unit L is discharging; when the working mode signal BURST_EN is a high-level signal, the second enable signal ENOCP remains low to disable the third comparator COMP3 of the overcurrent protection circuit OCP. That is, in the light load state, the BOOST circuit will keep the overcurrent protection circuit OCP in the off state for most of the time, so as to achieve ultra-low static power consumption of the overcurrent protection circuit OCP in the light load state.

[0155] Through the above method, the BOOST circuit of the present application can adaptively enable and stop the overcurrent protection circuit according to different load states and operating stages, thus effectively reducing the overall power consumption of the BOOST circuit and further improving the working efficiency of the BOOST circuit.

[0156] In one embodiment, as Figure 16 shown, the present application provides an overcurrent protection method, which is applied to the BOOST circuit 200 with overcurrent protection as described in any one of the above embodiments; the method includes the following steps S162 to step S164. Among them:

[0157] Step S162, if it is determined according to the output voltage signal that the BOOST circuit is in the heavy load state, the overcurrent protection circuit is turned on in the charging stage and turned off in the freewheeling stage.

[0158] Step S164, if it is determined according to the output voltage signal that the BOOST circuit is in the light load state, the working state of the overcurrent protection circuit changes with the periodic working mode signal: when the periodic working mode signal is at a low level, the overcurrent protection circuit is turned on in the charging stage and turned off in the freewheeling stage; when the periodic working mode signal is at a high level, the overcurrent protection circuit is turned off.

[0159] Among them, the periodic working mode signal can be the working mode signal with periodically changing high and low levels output by the differential amplification circuit described in the above embodiments.

[0160] It can be understood that the specific implementation manners of the steps of the method embodiments of the present application are already included in the above BOOST circuit embodiments, and will not be elaborated herein.

[0161] It should be understood that although the steps in the flowcharts involved in the method embodiments described above are shown in sequence according to the indications of the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear indication in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily executed at the same moment, but can be executed at different moments. The execution order of these steps or stages is not necessarily sequential, but can be executed alternately or in turn with at least a part of other steps or steps or stages in other steps.

[0162] In one embodiment, the present application provides a booster, which includes a BOOST circuit with overcurrent protection as described in any one of the above embodiments.

[0163] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope recorded in the present application.

[0164] The above-described embodiments only represent several implementation manners of the present application. Their descriptions are relatively specific and detailed, but should not be construed as limiting the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A BOOST circuit with overcurrent protection, characterized in that Comprising: A switching circuit; A differential amplifier circuit, the non-inverting input terminal of the differential amplifier circuit is used to obtain a reference voltage signal, the inverting input terminal of the differential amplifier circuit is used to obtain a feedback signal, and the feedback signal is obtained based on the output voltage signal of the BOOST circuit; the first output terminal of the differential amplifier circuit is used to output a working mode signal, and the working mode signal characterizes the current load state of the BOOST circuit; And, An overcurrent protection circuit, which is used to output a first enable signal according to the detected inductance voltage signal flowing into the switching circuit and the working mode signal when the switching circuit operates; the first enable signal is used to enable the differential amplifier circuit.

2. The BOOST circuit according to claim 1, wherein Further comprising: A first comparator, the non-inverting input terminal of the first comparator is connected to one end of the switching circuit, and the inverting input terminal of the first comparator is connected to the second output terminal of the differential amplifier circuit; A control logic circuit, the first input terminal of the control logic circuit is connected to the output terminal of the first comparator, the second input terminal of the control logic circuit is used to be connected to an oscillator, and the output terminal of the control logic circuit is connected to the control terminal of the switching circuit; Wherein, the output terminal of the control logic circuit is used to output a first switching signal to determine the operation of the switching circuit; the first enable signal is further used to enable the first comparator and the control logic circuit.

3. The BOOST circuit according to claim 2, wherein The oscillator is used to output a periodic oscillation signal to the control logic circuit; the output terminal of the first comparator is used to output a mode selection signal; the first enable signal is further used to enable the oscillator; If the oscillation signal input to the control logic circuit is a rising edge signal, the first switching signal output by the control logic circuit controls the switching circuit to conduct; If the mode selection signal input to the control logic circuit is a rising edge signal, the first switching signal output by the control logic circuit controls the switching circuit to cut off.

4. The BOOST circuit according to claim 2, characterized in that Further comprising: An inductor unit, one end of the inductor unit is used to obtain the input voltage signal of the BOOST circuit, and the other end of the inductor unit is connected to the other end of the switching circuit; A diode unit, the positive electrode of the diode unit is connected between the other end of the inductor unit and the other end of the switching circuit; A capacitor unit, one end of the capacitor unit is connected to the negative electrode of the diode unit, and the other end of the capacitor unit is used to be grounded.

5. The BOOST circuit according to claim 4, characterized in that, The switching circuit includes: A first switching transistor, one end of the first switching transistor is connected between the other end of the inductor unit and the positive electrode of the diode unit, and the control terminal of the first switching transistor is connected to the output terminal of the control logic circuit to obtain the first switching signal; A second switching transistor, one end of the second switching transistor is connected between the one end of the first switching transistor and the positive electrode of the diode unit, and the control terminal of the second switching transistor is connected to the output terminal of the control logic circuit to obtain the first switching signal; A second comparator, the non-inverting input terminal of the second comparator is connected to the other end of the first switching transistor, the inverting input terminal of the second comparator is connected to the other end of the second switch, and the output terminal of the second comparator is connected to the non-inverting input terminal of the first comparator; A first resistor, one end of the first resistor is connected between the non-inverting input terminal of the second comparator and the other end of the first switching transistor, the other end of the first resistor is connected between the inverting input terminal of the second comparator and the other end of the second switching transistor, and the other end of the first resistor is also grounded; A second resistor, one end of the second resistor is connected between the non-inverting input terminal of the first comparator and the output terminal of the second comparator, and the other end of the second resistor is grounded; Wherein, the first enable signal is further used to enable the second comparator.

6. The BOOST circuit according to claim 5, characterized in that, The sizes of the first switching transistor and the second switching transistor are in a preset proportional relationship.

7. The BOOST circuit according to claim 1, wherein Further included: A first voltage-dividing resistor, one end of the first voltage-dividing resistor is used to obtain the output voltage signal, and the other end of the first voltage-dividing resistor is connected to the inverting input terminal of the differential amplifier circuit; A second voltage-dividing resistor, one end of the second voltage-dividing resistor is connected between the other end of the first voltage-dividing resistor and the inverting input terminal of the differential amplifier circuit, and the other end of the second voltage-dividing resistor is grounded; Wherein, the feedback signal is a voltage signal obtained by voltage-dividing the output voltage signal through the first voltage-dividing resistor and the second voltage-dividing resistor.

8. The BOOST circuit according to claim 2, wherein The overcurrent protection circuit includes: A third comparator, the non-inverting input terminal of the third comparator is used to connect to a constant current source, and the enable terminal of the third comparator is used to obtain a second enable signal; A third switching transistor, one end of the third switching transistor is connected to the inverting input terminal of the third comparator, the other end of the third switching transistor is grounded, and the control terminal of the third switching transistor is used to obtain a second switching signal, and the second switching signal is the inverted signal of the first switching signal; A fourth switching transistor, one end of the fourth switching transistor is used to obtain the inductor voltage signal, the other end of the fourth switching transistor is connected between one end of the third switching transistor and the inverting input terminal of the third comparator, and the control terminal of the fourth switching transistor is used to obtain a third switching signal, and the third switching signal is the inverted signal of the second switching signal; A fifth switching transistor, one end of the fifth switching transistor is connected between the constant current source and the non-inverting input terminal of the third comparator, the other end of the fifth switching transistor is grounded, and the control terminal of the fifth switching transistor is used to obtain the second enable signal; Wherein, the second enable signal is obtained based on the operating mode signal and the third switching signal.

9. The BOOST circuit according to claim 8, wherein, The overcurrent protection circuit further includes: A first NOT gate circuit, the input terminal of the first NOT gate circuit is used to obtain the operating mode signal; A first AND gate circuit, the first input terminal of the first AND gate circuit is connected to the output terminal of the first NOT gate circuit, and the second input terminal of the first AND gate circuit is used to obtain the third switching signal; Wherein, the output terminal of the first AND gate circuit outputs the second enable signal.

10. The BOOST circuit according to claim 9, characterized in that, The third input terminal of the first AND gate circuit is used to obtain a system enable signal; wherein, the system enable signal is used to enable the BOOST circuit.

11. The BOOST circuit according to claim 8, wherein The overcurrent protection circuit further includes: a second AND gate circuit, the first input terminal of the second AND gate circuit is used to obtain a system enable signal, and the second input terminal of the second AND gate circuit is connected to the output terminal of the third comparator; wherein, the output terminal of the second AND gate circuit is used to output the first enable signal.

12. The BOOST circuit according to any one of claims 1 to 11, characterized in that when the differential amplification signal of the differential amplification circuit is greater than or equal to a preset voltage threshold, the working mode signal output by the differential amplification circuit is a low-level signal; the differential amplification signal is obtained based on the feedback signal and the reference voltage signal; when the differential amplification signal is less than the preset voltage threshold, the working mode signal output by the differential amplification circuit is a periodic square wave signal.

13. An overcurrent protection method, characterized in that, Applied to the BOOST circuit with overcurrent protection according to any one of claims 1 to 12; the method includes: If it is determined according to the output voltage signal that the BOOST circuit is in a heavy load state, the overcurrent protection circuit is turned on during the charging stage and turned off during the freewheeling stage; If it is determined according to the output voltage signal that the BOOST circuit is in a light load state, the working state of the overcurrent protection circuit changes with the periodic working mode signal: when the periodic working mode signal is at a low level, the overcurrent protection circuit is turned on during the charging stage and turned off during the freewheeling stage; when the periodic working mode signal is at a high level, the overcurrent protection circuit is turned off.

14. A booster, characterized in that, Including the BOOST circuit with overcurrent protection according to any one of claims 1 to 12.

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