Inductor current detection circuit, detection method and power converter

Abstract

The present invention discloses an inductor current detection circuit, detection method, and power converter. Based on the power converter's topology, a ramp voltage signal associated with the converter's input voltage and / or output voltage is constructed. This ramp voltage signal represents the magnitude of the rising (or falling) inductor current during the main switch's on (or off) period. The signal is then calculated with the inductor current signal sampled during the main switch's off (or on) period to obtain inductor current information within a switching cycle. This technical solution can obtain accurate inductor current information even when the main switch's on / off time is very short, broadening the range of the converter's input voltage or output voltage and thus providing a wide range of applications.

Description

Technical Field

[0001] The present invention relates to the field of switching power supplies, and more particularly to an inductor current detection circuit, a detection method, and a power converter. Background Art

[0002] Switching power supplies typically require providing a stable output signal to the load. Existing technology typically controls the output signal by turning the main switch on and off. This traditional control method utilizes a clock signal to control the on-state of the main switch, samples the current signal of the inductor in the switching power supply during the main switch's on-time, and controls the off-state of the main switch based on a comparison of the sampled current signal with a set reference signal, thereby controlling the output signal to the desired value.

[0003] In existing switching power supplies, according to the aforementioned control method, the inductor current rises linearly during the on-time period. The main switch is then controlled to turn off based on a comparison with a reference signal, causing the inductor current to decrease. Because the inductor current rises to its peak value only within a certain period after the main switch is turned on, and because the main switch generates high transient noise, the prior art generally sets a certain blanking period. Specifically, the inductor current information is sampled after the main switch is turned on and after a blanking period. Influenced by the performance of the main switch and circuit parameters, the blanking period in the prior art is often set relatively long to accurately sample the inductor current information. In some cases, the main switch's on-time is relatively short. Within this short on-time range, the blanking period setting results in inaccurate inductor current sampling, limiting the width of the switching power supply's input or output signals and impacting the application range of the switching power supply. Summary of the Invention

[0004] In view of this, an object of the present invention is to provide an inductor current detection circuit, a detection method and a switching power supply to solve the technical problems of inaccurate inductor current sampling and limited input and output signal adjustment width in the prior art.

[0005] The technical solution of the present invention is to provide an inductor current detection circuit for use in a power converter, wherein the power converter includes a main switch tube and an inductor connected to each other, and includes a current sampling circuit for sampling current information of the inductor to obtain an inductor current signal during the on-time or off-time of the main switch tube;

[0006] A ramp current construction circuit, which constructs a ramp current signal proportional to the input voltage or output voltage or the input voltage and the output voltage of the power converter based on the topology of the power converter;

[0007] The operation circuit receives the inductor current signal and the ramp voltage signal, and performs operation processing to obtain the inductor current signal within a switching cycle.

[0008] Preferably, the current sampling circuit samples the inductor current information of the main switch tube during the off time to obtain a first current signal;

[0009] During the on-time of the main switch, the ramp current construction circuit constructs a ramp current signal that is proportional to the input voltage of the power converter or the difference between the input voltage and the output voltage based on the topology of the power converter;

[0010] The operation circuit includes a superposition circuit, which receives the first current signal and the ramp current signal, performs superposition processing on them, and obtains a superimposed inductor current signal. The superimposed inductor current signal represents the inductor current signal of the main switch tube in one switching cycle.

[0011] Preferably, the proportionality coefficient of the direct proportional relationship is inversely proportional to the inductance value of the inductor.

[0012] Preferably, the proportionality coefficient of the direct proportional relationship is adjusted according to the inductance value of the inductor.

[0013] Preferably, it further includes an inductance value obtaining circuit, which presets the inductance value of the inductor to a plurality of different gear values, or

[0014] During the off time of the main switch tube, the inductance value obtaining circuit obtains the inductance value of the inductor according to the input voltage, the output voltage and the current change rate of the inductor.

[0015] Preferably, it also includes a conduction time detection circuit and an inductor current sampling circuit,

[0016] The inductor current sampling circuit samples the current information of the inductor during the on-time of the main switch tube to obtain an inductor current sampling signal;

[0017] The on-time detection circuit receives the inductor current sampling signal and the superimposed inductor current signal. The on-time detection circuit detects the on-time of the main switch tube. When the on-time is less than or equal to a preset time value, the superimposed inductor current signal is output; when the on-time is greater than the preset time value, the inductor current sampling signal is transmitted.

[0018] Preferably, the current sampling circuit samples the inductor current information of the main switch tube during the conduction time to obtain a second current signal;

[0019] During the off time of the main switch tube, the ramp current construction circuit constructs a second ramp current signal that is proportional to the output voltage of the power converter based on the topology of the power converter;

[0020] The operation circuit includes a subtraction circuit, which receives the second current signal and the second ramp current signal and performs subtraction processing to obtain the inductor current signal within a switching cycle of the main switch tube.

[0021] Preferably, the proportionality coefficient of the direct proportional relationship is inversely proportional to the inductance value of the inductor.

[0022] Preferably, the proportionality coefficient of the direct proportional relationship is adjusted according to the inductance value of the inductor.

[0023] Preferably, it further includes an inductance value obtaining circuit, which presets the inductance value of the inductor to a plurality of different gear values, or

[0024] During the on-time of the main switch tube, the inductance value obtaining circuit obtains the inductance value of the inductor according to the input voltage, the output voltage and the current change rate of the inductor.

[0025] The present invention discloses an inductor current detection method, which is applied to a power converter. The power converter includes a main switch tube and an inductor connected together, and includes the following steps:

[0026] S1: sampling the inductor current information of the main switch tube during the on-time period or the off-time period to obtain an inductor current signal;

[0027] S2: constructing a ramp voltage signal proportional to the input voltage or the output voltage of the power converter or the input voltage and the output voltage calculated based on the topology of the power converter;

[0028] S3: Receive the inductor current signal and the ramp voltage signal, and perform calculation processing to obtain the inductor current signal of the main power tube in one switching cycle.

[0029] The method further includes sampling the inductor current information of the main power tube during the off time to obtain a first current signal during the off time;

[0030] During the conduction time of the main power tube, a first ramp current signal is constructed based on the topology of the power converter, the first ramp current signal being proportional to the input voltage of the power converter or the difference between the input voltage and the output voltage;

[0031] The first current signal and the first ramp current signal are received and superimposed to obtain an inductor current signal of the main power tube in one switching cycle.

[0032] It further includes that the proportional coefficient of the direct proportional relationship is inversely proportional to the inductance value of the inductor.

[0033] It further includes adjusting the proportional coefficient of the direct proportional relationship according to the inductance value of the inductor.

[0034] It further includes presetting the inductance value of the inductor to a plurality of different gear values, or,

[0035] During the off time of the main switch tube, the inductance value of the inductor is obtained according to the input voltage, the output voltage, and the current change rate of the inductor.

[0036] The method further includes sampling the inductor current information of the main power tube during the conduction time to obtain a second current signal during the conduction time;

[0037] During the off time of the main power tube, a second ramp current signal is constructed based on the topology of the power converter and is proportional to the output voltage of the power converter;

[0038] The second current signal and the second ramp current signal are received and subtracted to obtain an inductor current signal of the main power tube in one switching cycle.

[0039] It further includes that the proportional coefficient of the direct proportional relationship is inversely proportional to the inductance value of the inductor.

[0040] It further includes adjusting the proportional coefficient of the direct proportional relationship according to the inductance value of the inductor.

[0041] It further includes presetting the inductance value of the inductor to a plurality of different gear values, or,

[0042] During the on-time of the main switch tube, the inductance value of the inductor is obtained according to the input voltage, the output voltage and the current change rate of the inductor.

[0043] The present invention discloses a power converter, comprising the above-mentioned inductor current detection circuit, a power stage circuit, a comparison circuit, and a logic and drive circuit.

[0044] The inductor current detection circuit is used to obtain the inductor current signal within a switching cycle.

[0045] The comparison circuit receives the inductor current signal and a reference signal to obtain a comparison signal, wherein the comparison signal is used to control the switching state of the main switch tube in the power stage circuit;

[0046] The logic and driving circuit receives a comparison signal and a clock signal output by the comparison circuit, and outputs a switch signal according to the comparison signal and the clock signal to control the on and off of the main switch tube.

[0047] The inductor current detection circuit structure of the present invention reconstructs a ramp current signal proportional to the input voltage, output voltage, or the difference between the input and output voltages based on the power converter's topology. This ramp current signal represents the magnitude of the rising (falling) inductor current when the main switch is on (or off). This signal is then combined with the inductor current signal sampled during the main switch's off (or on) period to obtain inductor current information for a complete switching cycle. This technical solution imposes no specific requirements on the blanking or switching times of the main switch, and the power converter can adjust the input or output signal width as needed, thus broadening its applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a circuit block diagram of a first embodiment of an inductor current detection circuit according to the present invention;

[0049] Figure 1 (a) Figure 1 An implementation of a mid-slope current reconstruction circuit;

[0050] Figure 1 (b) Figure 1 The waveform of the inductor current signal in ;

[0051] Figure 2 is a circuit block diagram of a second embodiment of an inductor current detection circuit according to the present invention;

[0052] Figure 3 is a circuit block diagram of a third embodiment of an inductor current detection circuit according to the present invention;

[0053] Figure 4 is a flow chart of the inductor current detection method according to the present invention. DETAILED DESCRIPTION

[0054] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings, but the present invention is not limited to these embodiments and covers any substitution, modification, equivalent method and solution made within the spirit and scope of the present invention.

[0055] To provide the public with a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention. However, those skilled in the art can fully understand the present invention even without the description of these details in the circuit block diagram of the third embodiment of the inductor current detection circuit according to the present invention.

[0056] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. It should be noted that the drawings are simplified and not to exact proportions, and are only used for the purpose of conveniently and clearly illustrating the embodiments of the present invention.

[0057] like Figure 1 Figure 2 shows a circuit block diagram of an inductor current detection circuit according to the present invention, which is applied to a power converter. This embodiment uses a buck topology as an example. This topology includes a main switch Q1, an inductor L connected to the main switch Q1, a synchronous rectifier Q2, and an output capacitor Co. The power converter receives an input signal Vin, converts it into a DC output signal Vout through switching by the main switch Q1, and supplies it to a load. The voltage across the output capacitor Co is recorded as the output voltage signal Vout.

[0058] like Figure 1 As shown, the power converter includes an inductor current detection circuit 1, a comparator CMP1 and a logic and drive circuit 2. Here, the power stage converter also includes some other devices for realizing input and output power conversion, which are not directly related to the technical solution of the present invention. Figure 1 Not shown in the figure.

[0059] refer to Figure 1 The inductor current detection circuit 1 of the embodiment of the present invention includes a current sampling circuit 1-1, a ramp current construction circuit 1(b) and a superposition circuit 1-3. The current sampling circuit 1-1 samples the inductor current information of the main switch tube during the off time to obtain a first current signal I Bot (Here the voltage signal V corresponding to the first current signal is used IBot Here, the current sampling circuit can be implemented by devices such as resistors, but is not limited thereto.

[0060] Afterwards, during the conduction time of the main power tube, the ramp current construction circuit 1-2 constructs a first ramp current signal that is proportional to the input voltage of the power converter or the difference between the input voltage and the output voltage based on the topology of the power converter. Here, the power converter is a synchronous buck topology, and the first ramp current signal is constructed to be proportional to the difference between the input voltage and the output voltage of the power converter. The specific implementation method can be as follows Figure 1 As shown in (a), but not limited thereto, the ramp current construction circuit includes a current source I, a charging capacitor C, and a first switch S connected in parallel with the charging capacitor. The current source I is used to charge the charging capacitor C. The voltage signal across the charging capacitor is a first ramp voltage signal V representing the first ramp current signal. COMPIn this embodiment, the size of the current source is set to be directly proportional to the difference between the input voltage and the output voltage of the power converter, and the proportional coefficient K is inversely proportional to the inductance L of the inductor.

[0061] The switching state of the first switch S is opposite to the switching state of the main switch tube Q, and during the on-time period of the main switch tube, such as the Ton time, the charging capacitor is charged by the current source until the on-time ends; during the off-time period of the main switch tube, such as the Toff time, the charging capacitor is discharged to zero.

[0062] The operation circuit includes a superposition circuit 1-3, which receives the first current signal and the first ramp current signal and performs superposition processing to obtain the inductor current signal within a switching cycle, such as Figure 1 The inductor voltage signal V that represents the inductor current information IPK Here, the superposition circuit is specifically an adder.

[0063] Combine Figure 1 (b) Figure 1 According to the waveform diagram in the above circuit, it can be inferred that the current I of the current source is set to I∝K*(Vin-Vo). When the main switch tube Q1 is turned on, the first switch S is turned off, and the current source I charges the charging capacitor. Then the first ramp voltage signal is correspondingly: V COMP ∝K*(Vin-Vo). Ideally, the proportional coefficient K = 1 / L. In actual circuits, the inductance L may vary slightly. The following paragraphs will introduce how to adjust the proportional coefficient K by dynamically adjusting the inductance value. Figure 1 (b) For a synchronous buck topology, the current waveform of inductor L is a triangular wave. During the main switch's on-time, Ton, the current in main switch Q1 increases, and during the off-time, Toff, the current in synchronous switch Q2 decreases. During the on-time, the inductor current is equal to the current in main switch Q1 and increases linearly. According to the operating volt-second product principle of a buck circuit, the magnitude of the inductor current rise, ΔI, is the integral of (Vin - Vo) / L over the on-time. Therefore, the first ramp current signal constructed by the aforementioned ramp current construction circuit can represent the magnitude of the inductor current rise, ΔI.

[0064] In the continuous conduction mode, at time t1, the inductor current is at the end of the off time, and the inductor current at the bottom of the valley can be obtained by sampling. Bot Then, during the on-time, such as the time period from t1 to t2, the ramp current construction circuit of the embodiment of the present invention is used to construct and output the first ramp current signal I COMP (The corresponding voltage is expressed as V COMP),like Figure 1 As shown by the dotted line in (b), at the end of the on-time, the first ramp current signal I COMP The magnitude of the inductor current superimposed on the valley bottom is I Bot The magnitude of the inductor current during the main power tube conduction period can be obtained. In this way, the inductor current information within a switching cycle can be obtained through this construction method.

[0065] Here, the inductance value L of the inductor may be preferably a fixed value. In other embodiments, the proportional coefficient of the direct proportional relationship may be adjusted according to the inductance value of the inductor, such as the inductor current detection circuit further including an inductor current acquisition circuit (in Figure 1 (not shown), the inductor current acquisition circuit pre-sets the inductor value to a plurality of different gear values, or, when the main switch is off, the inductor current acquisition circuit obtains the inductor value based on the input voltage, output voltage, and the current change rate of the inductor. Those skilled in the art will appreciate that, based on the volt-second product principle of the circuit, there is a fixed formula relationship between the current change rate of the inductor, the inductor value, and the input voltage or output voltage. Therefore, based on the formula, the inductor value can be obtained when the current change rate of the inductor and the input voltage or output voltage are known. In this way, different control chips can obtain different inductance values, thereby obtaining a corresponding accurate proportional system, making the calculation of the ramp current more accurate. Alternatively, several different gear values ​​can be pre-set, and in actual application, the appropriate inductance value can be selected according to the chip in the circuit, which can also make the calculation of the ramp current more accurate.

[0066] Afterwards, the comparator CMP in the power converter receives the inductor current signal (which can be the corresponding inductor voltage signal V IPK The power stage circuit comprises a logic and drive circuit 2, which receives the comparison signal output by the comparator and a clock signal, and outputs a switching signal based on the comparison signal and the clock signal to control the on / off state of the main switch.

[0067] As can be seen from the above process, the technical solution of the embodiment of the present invention superimposes a ramp current signal representing the rise of the inductor current on the sampled first current signal, thereby obtaining the expected inductor current magnitude during the on-time period through virtual calculation. The first ramp current signal representing the rise of the inductor current in the present invention is calculated based on the input and output voltages of the power topology, resulting in a rising slope that is consistent or substantially consistent with the actual inductor current. The inductor current detection circuit of the present invention is unaffected by the on-time or blanking time, accurately determining the inductor current magnitude, and can broaden the input and output voltage ranges of the power converter, thus providing a wide range of applications.

[0068] refer to Figure 2 This is a circuit block diagram of a second embodiment of the inductor current detection circuit according to the present invention. Figure 1 On the basis of the embodiment shown, a conduction time detection circuit 3 is added (which can be but not limited to a switch control signal V Q The on-time detection circuit 3 detects the on-time Ton of the main switch tube. When the on-time is less than or equal to a preset time value, the preset time is the time for accurately sampling the inductor current. Then, the superimposed inductor current signal I is selected. IPK1 (The corresponding voltage is expressed as V IPK1 ) is transmitted to the subsequent circuit; the inductor current sampling circuit 4 samples the current information of the inductor during the conduction time of the main switch tube to obtain the inductor current signal I IPK2 , (the corresponding voltage is expressed as V IPK2 ), when the conduction time is greater than the preset time value, the inductor current signal I IPK2 The signal is then transmitted to the subsequent circuit, which may be a comparator or other logic and control circuit.

[0069] According to the circuit of this embodiment, if the main switch's on-time is short, the constructed inductor current signal is not restricted by the on-time, allowing accurate inductor current information to be obtained. If the main switch's on-time is long, there is no need to use virtual constructed inductor current information; instead, the inductor current information can be obtained directly through sampling, resulting in a more realistic and accurate sampled signal.

[0070] The above embodiment takes the buck topology as an example. Those skilled in the art should understand that in other embodiments, the power stage circuit can adopt any suitable DC-DC topology, such as a buck topology, a boost topology, a synchronous boost topology, a flyback, a synchronous flyback and other suitable topologies. For example, in the case of a boost topology, during the time when the main switch tube is on, the rising inductor current is directly proportional to the input voltage. In this way, when constructing the ramp current signal, the current source is set to be directly proportional to the input voltage. In this way, an accurate inductor current signal can be obtained within one switching cycle.

[0071] refer to Figure 3 The circuit block diagram of the third embodiment of the inductor current detection circuit according to the present invention is shown. In this embodiment, the power converter takes the buck topology circuit structure as an example. Figure 1 The embodiment is the same. In this embodiment, the inductor current detection circuit includes a current sampling circuit 1-1, a ramp current construction circuit 1-2 and a subtraction circuit 1-3. The current sampling circuit 1-1 samples the inductor current information of the main switch tube during the conduction time to obtain a second current signal I IPK (The corresponding voltage signal is expressed as V IPK ); During the off time of the main switch tube, the ramp current construction circuit 1-2 constructs a second ramp current signal proportional to the output voltage of the power converter based on the topology of the power converter (the corresponding second ramp voltage signal is expressed as V COMP ); The subtraction circuit 1-3 receives the peak voltage signal V IPK and the ramp voltage signal V COMP , performing subtraction processing to obtain the inductor current signal within one switching cycle of the main switch tube.

[0072] Here, the second ramp voltage signal V COMP The proportional coefficient K of the proportional relationship is inversely proportional to the inductance value L of the inductor. Similarly, here, the inductance value L of the inductor can be preferably a fixed value. In other embodiments, the proportional coefficient of the proportional relationship can be adjusted according to the inductance value of the inductor. For example, the inductor current detection circuit further includes an inductor current acquisition circuit (in Figure 3(not shown), the inductor current acquisition circuit pre-sets the inductor's inductance value to a plurality of different gear values, or, during the on-time of the main switch, the inductor current acquisition circuit acquires the inductor's inductance value based on the input voltage, output voltage, and the current change rate of the inductor. Those skilled in the art will appreciate that, based on the volt-second product principle of the circuit, there is a fixed formula relationship between the inductor's current change rate, the inductor's inductance value, and the input voltage or output voltage. Therefore, based on the formula, the inductor's inductance value can be obtained when the current change rate of the inductor, as well as the input voltage and output voltage, is known. In this way, different control chips can obtain different inductance values, thereby obtaining a corresponding accurate proportional system, making the calculation of the ramp current more accurate.

[0073] The slope current reconstruction circuit in this embodiment includes a current source, a charging capacitor and a first switch connected in parallel with the charging capacitor, the current source is used to charge the charging capacitor, and the voltage signal at both ends of the charging capacitor is a second slope voltage signal representing the second slope current signal, wherein the size of the current source is set in direct proportion to the output voltage of the power converter, and the switching state of the first switch is the same as the switching state of the main switch tube. During the off time period of the main switch tube, the charging capacitor is charged until the off time ends; during the on time period of the main switch tube, the charging capacitor is discharged to zero. The slope current reconstruction circuit in this embodiment and Figure 1 (a) is similar in structure, except that the switching state of the first switch is Figure 1 (a) is the opposite. According to the circuit structure and control relationship of this embodiment, during the off period of the main switch tube, the charging capacitor is charged by the current source. The current of the current source is set to be proportional to the output voltage. The second ramp voltage signal obtained is proportional to the output voltage. For the buck circuit, during the off period of the main switch tube, the current of the inductor decreases. The magnitude of the decreasing current is proportional to the output voltage. Therefore, the constructed second ramp voltage signal V COMP The magnitude of the decreasing inductor current can be represented by sampling the inductor current signal at the end of the conduction time and subtracting the ramp voltage signal V COMP Thus, according to the circuit solution of this embodiment, when the off time of the main switch is short, the constructed inductor current signal is not limited by the off time, and accurate inductor current information can be obtained.

[0074] In summary, in the embodiments of the present invention, a current sampling circuit samples the inductor current information during the on-time or off-time of the main power tube. A ramp current construction circuit then constructs a ramp current signal proportional to the input voltage or output voltage, or the input and input voltages, based on the topology of the power converter. An operation circuit receives the inductor current signal and the ramp current signal and performs superposition or subtraction processing to obtain the inductor current information within a switching cycle. This technical solution is not limited by the blanking time or switching time of the main switch tube. The power converter can adjust the input voltage or output voltage range as needed, thus having a wide range of applications.

[0075] Finally, if Figure 4 As shown, the present invention discloses an inductor current detection method, which is applied to a power converter. The power converter includes a main switch tube and an inductor connected, including the steps of:

[0076] S1: sampling the inductor current information of the main switch tube during the on-time period or the off-time period to obtain an inductor current signal;

[0077] S2: constructing a ramp voltage signal proportional to the input voltage or the output voltage of the power converter or the input voltage and the output voltage calculated based on the topology of the power converter;

[0078] S3: Receive the inductor current signal and the ramp voltage signal, and perform calculation processing to obtain the inductor current signal of the main power tube in one switching cycle.

[0079] The method further comprises: sampling the inductor current information of the main power tube during the off time to obtain a first current signal during the off time;

[0080] During the conduction time of the main power tube, a first ramp current signal is constructed based on the topology of the power converter, the first ramp current signal being proportional to the input voltage of the power converter or the difference between the input voltage and the output voltage;

[0081] The first current signal and the first ramp current signal are received and superimposed to obtain an inductor current signal of the main power tube in one switching cycle.

[0082] Furthermore, the proportional coefficient of the direct proportional relationship is inversely proportional to the inductance value of the inductor.

[0083] Furthermore, the proportional coefficient of the direct proportional relationship is adjusted according to the inductance value of the inductor.

[0084] Furthermore, the inductance value of the inductor is preset to a plurality of different gear values, or,

[0085] During the off time of the main switch tube, the inductance value of the inductor is obtained according to the input voltage, the output voltage, and the current change rate of the inductor.

[0086] Furthermore, it includes: sampling the inductor current information of the main power tube during the conduction time to obtain a second current signal during the conduction time;

[0087] During the off time of the main power tube, a second ramp current signal is constructed based on the topology of the power converter and is proportional to the output voltage of the power converter;

[0088] The second current signal and the second ramp current signal are received and subtracted to obtain an inductor current signal of the main power tube in one switching cycle.

[0089] Furthermore, the proportional coefficient of the direct proportional relationship is inversely proportional to the inductance value of the inductor.

[0090] Furthermore, the proportional coefficient of the direct proportional relationship is adjusted according to the inductance value of the inductor.

[0091] Furthermore, the inductance value of the inductor is preset to a plurality of different gear values, or,

[0092] During the on-time of the main switch tube, the inductance value of the inductor is obtained according to the input voltage, the output voltage and the current change rate of the inductor.

[0093] Finally, the present invention discloses a power converter, wherein the above-mentioned inductor current detection circuit further includes a power stage circuit, a comparison circuit, and a logic and drive circuit.

[0094] The inductor current detection circuit is used to obtain the inductor current signal within a switching cycle.

[0095] The comparison circuit receives the inductor current signal and a reference signal to obtain a comparison signal, wherein the comparison signal is used to control the switching state of the main switch tube in the power stage circuit;

[0096] The logic and driving circuit receives a comparison signal and a clock signal output by the comparator, and outputs a switching signal according to the comparison signal and the clock signal to control the on and off of the main switch tube.

[0097] Similarly, the power converter described above can adjust the width range of input and output signals according to needs, and has a wide range of applications.

[0098] The above-described embodiments do not constitute a limitation on the scope of protection of this technical solution. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the above-described embodiments shall be included in the scope of protection of this technical solution.

Claims

1. An inductor current detection circuit, used in a power converter, wherein the power converter includes a main switch tube and an inductor connected to each other, characterized in that: include, A current sampling circuit, configured to sample the current information of the inductor to obtain the inductor current signal of the main switch tube during the on-time or the off-time; A ramp current construction circuit, which constructs a ramp current signal proportional to the input voltage or output voltage or the input voltage and output voltage of the power converter based on the topology of the power converter; an operation circuit, receiving the inductor current signal and the ramp current signal, and performing operation processing to obtain the inductor current signal within a switching cycle; The current sampling circuit samples the inductor current information of the main switch tube during the off time to obtain a first current signal; During the on-time of the main switch, the ramp current construction circuit constructs a ramp current signal that is proportional to the input voltage of the power converter or the difference between the input voltage and the output voltage based on the topology of the power converter; The operation circuit includes a superposition circuit, which receives the first current signal and the ramp current signal, performs superposition processing on them, and obtains a superimposed inductor current signal. The superimposed inductor current signal represents the inductor current signal of the main switch tube in one switching cycle.

2. The inductor current detection circuit according to claim 1, wherein: The proportional coefficient of the direct proportional relationship is inversely proportional to the inductance value of the inductor.

3. The inductor current detection circuit according to claim 1, wherein: The proportional coefficient of the direct proportional relationship is adjusted according to the inductance value of the inductor.

4. The inductor current detection circuit according to claim 3, wherein: It also includes an inductance value obtaining circuit, which presets the inductance value of the inductor to a plurality of different gear values, or During the off time of the main switch tube, the inductance value obtaining circuit obtains the inductance value of the inductor according to the input voltage, the output voltage and the current change rate of the inductor.

5. The inductor current detection circuit according to claim 1, wherein: It also includes a conduction time detection circuit and an inductor current sampling circuit. The inductor current sampling circuit samples the current information of the inductor during the on-time of the main switch tube to obtain an inductor current sampling signal; The on-time detection circuit receives the inductor current sampling signal and the superimposed inductor current signal, detects the on-time of the main switch, and selects to output the superimposed inductor current signal when the on-time is less than or equal to a preset time value; When the conduction time is greater than a preset time value, the inductor current sampling signal is selected to be transmitted.

6. A method for detecting inductor current, applied to a power converter, wherein the power converter comprises a main switch tube and an inductor connected, characterized in that: Including steps: S1: sampling the inductor current information of the main switch tube during the on-time period or the off-time period to obtain an inductor current signal; S2: constructing a ramp current signal proportional to the input voltage or output voltage or the calculated input voltage and output voltage of the power converter based on the topology of the power converter; S3: receiving the inductor current signal and the ramp current signal, and performing calculation processing to obtain the inductor current signal of the main switch tube in one switching cycle; Sampling the inductor current information of the main switch tube during the off time to obtain a first current signal during the off time; During the on-time of the main switch, a first ramp current signal is generated based on the topology of the power converter, and is proportional to the input voltage of the power converter or the difference between the input voltage and the output voltage; The first current signal and the first ramp current signal are received and superimposed to obtain an inductor current signal of the main switch tube in one switching cycle.

7. The inductor current detection method according to claim 6, wherein: The proportional coefficient of the direct proportional relationship is inversely proportional to the inductance value of the inductor.

8. The inductor current detection method according to claim 6, wherein: The proportional coefficient of the direct proportional relationship is adjusted according to the inductance value of the inductor.

9. The inductor current detection method according to claim 8, wherein: The inductance value of the inductor is preset to a plurality of different gear values, or, During the off time of the main switch tube, the inductance value of the inductor is obtained according to the input voltage, the output voltage, and the current change rate of the inductor.

10. A power converter, characterized in that: The inductor current detection circuit comprises the inductor current detection circuit according to any one of claims 1 to 5, further comprising a power stage circuit, a comparison circuit, and a logic and drive circuit. The inductor current detection circuit is used to obtain the inductor current signal within a switching cycle. The comparison circuit receives the inductor current signal and a reference signal to obtain a comparison signal, wherein the comparison signal is used to control the switching state of the main switch tube in the power stage circuit; The logic and driving circuit receives a comparison signal and a clock signal output by the comparison circuit, and outputs a switch signal according to the comparison signal and the clock signal to control the on and off of the main switch tube.

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