Inductive current detection circuit, detection method and power converter

Abstract

The invention discloses an inductive current detection circuit, a detection method and a power converter. A ramp voltage signal associated with an input voltage and / or an output voltage of the power converter is constructed according to a topological structure of the power converter; the ramp voltage signal represents the magnitude of the rising (or falling) inductive current in the turn-on (or turn-off) time period of the main switching tube, and then the ramp voltage signal is calculated with an inductive current signal sampled in the turn-off (or turn-on) time period of the main switching tube, so that inductive current information in a switching period is obtained. According to the technical scheme, accurate inductive current information can still be obtained under the condition that the switching time of the main switching tube is very short, the range of the input voltage or the output voltage of the power converter can be widened, and the application range is wide.

Description

[0001] This application is a divisional application of the invention patent application filed on August 13, 2020, with application number CN202010810903.1 and invention title "An Inductor Current Detection Circuit, Detection Method and Power Converter". Technical Field

[0002] This invention relates to the field of switching power supplies, and more specifically, to an inductor current detection circuit, detection method, and power converter. Background Technology

[0003] In the use of switching power supplies, a stable output signal is typically required to supply the load. Current technology generally controls the magnitude of the output signal by controlling the on / off state of the main switching transistor (MTT). The traditional control method uses a clock signal to control the on-state of the MTT, samples the current signal of the inductor in the power supply during the MTT's on-state time, and controls the MTT's off-state based on a comparison of the sampled current signal with a set reference signal, thereby controlling the output signal to meet the desired value.

[0004] In existing switching power supplies, according to the control method described above, the inductor current rises linearly during the conduction period. Then, based on the comparison with the reference signal, the main switch is turned off, and the inductor current decreases. Since the inductor current only reaches its peak value after the main switch is turned on, and due to the high instantaneous noise of the main switch, existing technologies typically set a blanking time period. That is, the inductor current information is sampled after the main switch has turned on and the blanking time period has elapsed. Due to the performance of the main switch and the circuit parameters, the blanking time period in existing technologies is often set to be relatively long to obtain accurate inductor current information. In some cases, the conduction time of the main switch is short. Within this short conduction time range, the blanking time setting leads to inaccurate inductor current sampling, limiting the width of the input or output signal of the switching power supply and affecting its application range. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide an inductor current detection circuit, detection method and 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.

[0006] The technical solution of the present invention is to provide an inductor current detection circuit for use in a power converter. The power converter includes a main switch and an inductor connected to each other, and includes a current sampling circuit for sampling the current information of the inductor to obtain the inductor current signal of the main switch during the on-time or off-time.

[0007] A ramp current construction circuit constructs a ramp current signal that is proportional to the input voltage or output voltage or the input voltage and output voltage after calculation, based on the topology of the power converter.

[0008] The arithmetic circuit receives the inductor current signal and the ramp voltage signal, and performs arithmetic processing to obtain the inductor current signal within one switching cycle.

[0009] Preferably, the current sampling circuit samples the inductor current information of the main switch during the off-time to obtain a first current signal;

[0010] During the conduction time of the main switch, the ramp current construction circuit constructs a ramp current signal that is proportional to the input voltage or the difference between the input voltage and the output voltage of the power converter based on the topology of the power converter.

[0011] The operational circuit includes a superposition circuit, which receives the first current signal and the ramp current signal, performs superposition processing to obtain a superimposed inductor current signal, and the superimposed inductor current signal represents the inductor current signal of the main switch in one switching cycle.

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

[0013] Preferably, the proportionality coefficient of the direct proportional relationship is adjusted according to the inductance value of the inductor.

[0014] Preferably, it further includes an inductance value acquisition circuit, which pre-sets the inductance value of the inductor to multiple different range values, or...

[0015] During the off-time of the main switch, the inductance value acquisition circuit obtains the inductance value based on the input voltage, the output voltage, and the rate of change of the inductor current.

[0016] Preferably, it also includes a conduction time detection circuit and an inductor current sampling circuit.

[0017] The inductor current sampling circuit samples the current information of the inductor during the conduction time of the main switch to obtain the inductor current sampling signal.

[0018] The conduction time detection circuit receives the inductor current sampling signal and the superimposed inductor current signal. The conduction time detection circuit detects the conduction time of the main switch. When the conduction time is less than or equal to a preset time value, the superimposed inductor current signal is output. When the conduction time is greater than the preset time value, the inductor current sampling signal is transmitted.

[0019] Preferably, the current sampling circuit samples the inductor current information of the main switch during the conduction time to obtain a second current signal;

[0020] During the turn-off time of the main switch, 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.

[0021] The operational 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 one switching cycle of the main switch.

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

[0023] Preferably, the proportionality coefficient of the direct proportional relationship is adjusted according to the inductance value of the inductor.

[0024] Preferably, it further includes an inductance value acquisition circuit, which pre-sets the inductance value of the inductor to multiple different range values, or...

[0025] During the conduction time of the main switch, the inductance value acquisition circuit obtains the inductance value based on the input voltage, the output voltage, and the rate of change of the inductor current.

[0026] This invention discloses an inductor current detection method applied in a power converter, the power converter including a connected main switch transistor and an inductor, comprising the following steps:

[0027] S1: Sample the inductor current information of the main switch during the on-time or off-time period to obtain the inductor current signal;

[0028] S2: Based on the topology of the power converter, construct a ramp voltage signal that is proportional to the input voltage or output voltage or the input voltage and the input voltage after calculation.

[0029] S3: Receive the inductor current signal and the ramp voltage signal, and perform calculations to obtain the inductor current signal of the main switch in one switching cycle.

[0030] Further, it includes sampling the inductor current information of the main switch during the turn-off time to obtain a first current signal during the turn-off time;

[0031] During the conduction time of the main switch, a first ramp current signal is constructed based on the topology of the power converter and is directly proportional to the input voltage or the difference between the input voltage and the output voltage of the power converter.

[0032] The first current signal and the first ramp current signal are received and superimposed to obtain the inductor current signal of the main switch in one switching cycle.

[0033] Furthermore, the proportionality coefficient of the aforementioned direct proportional relationship is inversely proportional to the inductance value.

[0034] Furthermore, the proportional coefficient of the positive proportional relationship is adjusted according to the inductance value of the inductor.

[0035] This further includes presetting the inductance value of the inductor to multiple different levels, or...

[0036] During the turn-off time of the main switch, the inductance value is obtained based on the input voltage, the output voltage, and the rate of change of the inductor current.

[0037] The method further includes sampling the inductor current information of the main switch during the conduction time to obtain a second current signal during the conduction time;

[0038] During the turn-off time of the main switch, a second ramp current signal that is proportional to the output voltage of the power converter is constructed based on the topology of the power converter.

[0039] The second current signal and the second ramp current signal are received and subtracted to obtain the inductor current signal of the main switch in one switching cycle.

[0040] Furthermore, the proportionality coefficient of the aforementioned direct proportional relationship is inversely proportional to the inductance value.

[0041] Furthermore, the proportional coefficient of the positive proportional relationship is adjusted according to the inductance value of the inductor.

[0042] This further includes presetting the inductance value of the inductor to multiple different levels, or...

[0043] During the conduction time of the main switch, the inductance value is obtained based on the input voltage, the output voltage, and the rate of change of the inductor current.

[0044] This invention discloses a power converter, including the aforementioned inductor current detection circuit, and further including a power stage circuit, a comparator circuit, and logic and drive circuits.

[0045] The inductor current detection circuit is used to obtain the inductor current signal within one switching cycle.

[0046] The comparator circuit receives the inductor current signal and a reference signal to obtain a comparison signal, which is used to control the switching state of the main switch in the power stage circuit.

[0047] The logic and drive circuit receives a comparison signal and a clock signal output by the comparison circuit, and outputs a switching signal to control the on / off state of the main switch transistor based on the comparison signal and the clock signal.

[0048] The inductor current detection circuit structure of this invention reconstructs a ramp current signal that is directly 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 characterizes the magnitude of the rising (or falling) inductor current when the main switch is turned on (or off). This signal is then compared with the inductor current signal sampled during the main switch's off (or on) period to obtain the inductor current information for a complete switching cycle. This technical solution does not have special requirements for the blanking time or switching time of the main switch, and the power converter can adjust the width range of the input or output signals as needed, making it widely applicable. Attached Figure Description

[0049] Figure 1 This is a circuit block diagram of a first embodiment of the inductor current detection circuit according to the present invention;

[0050] Figure 1 (a) is Figure 1 One implementation of a mid-slope current reconstruction circuit;

[0051] Figure 1 (b) is Figure 1 Waveform of the inductor current signal in the image;

[0052] Figure 2 This is a circuit block diagram of a second embodiment of the inductor current detection circuit according to the present invention;

[0053] Figure 3 This is a circuit block diagram of a third embodiment of the inductor current detection circuit according to the present invention;

[0054] Figure 4 This is a flowchart of the inductor current detection method according to the present invention. Detailed Implementation

[0055] 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. The present invention covers any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of the present invention.

[0056] 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 invention, but those skilled in the art can fully understand the invention without these details.

[0057] The invention is described in more detail below by way of example with reference to the accompanying drawings. It should be noted that the drawings are in a simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0058] like Figure 1 The diagram shows a circuit block diagram of an inductor current detection circuit according to the present invention. This inductor current detection circuit is applied in a power converter. Taking a buck topology as an example, the power converter in this embodiment 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, which is switched by the main switch Q1, and outputs a DC output signal Vout to supply the load. The voltage across the output capacitor Co is denoted as the output voltage signal Vout.

[0059] 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. The power stage converter also includes other devices that implement input-output power conversion, which are not directly related to the technical solution of this invention. Figure 1 Not shown in the image.

[0060] refer to Figure 1 The inductor current detection circuit 1 of this embodiment 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 during the turn-off time to obtain a first current signal I. Bot (Here, the voltage signal V corresponding to the first current signal is used) IBot (For identification purposes), the current sampling circuit here can be implemented by components such as resistors, but is not limited to these.

[0061] Subsequently, during the conduction time of the main switch, the ramp current construction circuit 1-2 constructs a first ramp current signal based on the topology of the power converter, which is proportional to the input voltage or the difference between the input and output voltages of the power converter. Here, the power converter is a synchronous buck topology, so the first ramp current signal is constructed to be directly proportional to the difference between the input and output voltages of the power converter. A specific implementation method can be as follows: Figure 1As 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, and the voltage signal across the charging capacitor is a first ramp voltage signal V that characterizes the first ramp current signal. COMP In this embodiment, the magnitude 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 proportionality coefficient K is inversely proportional to the inductance value L of the inductor.

[0062] The switching state of the first switch S is opposite to the switching state of the main switch Q. During the on-time period of the main switch Q, 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 Q, such as the Toff time, the charging capacitor is discharged to zero.

[0063] The operational circuit includes superposition circuits 1-3. These superposition circuits receive the first current signal and the first ramp current signal, and perform superposition processing to obtain the inductor current signal within one switching cycle. Figure 1 The inductor voltage signal V, which represents the inductor current information, is described in the text. IPK Here, the superposition circuit is specifically an adder.

[0064] Combination Figure 1 (b) is Figure 1 Based on the waveform diagram and the circuit described above, it can be deduced that the current I of the current source is set to I∝K*(Vin-Vo). When the main switch Q1 is turned on, the first switch S is turned off, and the current source I charges the charging capacitor. Therefore, the corresponding first ramp voltage signal is: V COMP ∝K*(Vin-Vo), in ideal conditions, the proportionality coefficient K = 1 / L. In actual circuits, the inductance L will vary slightly. The following paragraph will introduce how to dynamically adjust the inductance value to adjust the value of the proportionality coefficient K. (Reference) Figure 1 (b) For the synchronous buck topology, the current waveform of inductor L is a triangular wave. During the on-time Ton of the main switch, the current of the main switch Q1 rises, and during the off-time Toff, the current of the synchronous switch Q2 decreases. During the on-time, the inductor current is equal to the current of the main switch Q1, showing a linear rise. According to the volt-second product principle of the 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 above ramp current construction circuit can characterize the magnitude of the inductor current rise ΔI.

[0065] In continuous conduction mode, for example, at time t1, when the inductor current is at the end of the off-time, the magnitude I of the inductor current at the valley can be obtained by sampling. Bot Then, during the conduction time, such as the time period from t1 to t2, the first ramp current signal I is generated and output through the ramp current generation circuit of this embodiment of the invention. COMP (The corresponding voltage is expressed as V) COMP ),like Figure 1 As shown by the dashed line in (b), the first ramp current signal I will be sent at the end of the conduction time. COMP The magnitude of the inductor current I superimposed on the valley bottom Bot The magnitude of the inductor current during the on-time of the main switch can be obtained. Thus, by constructing this method, inductor current information over a single switching cycle can be obtained.

[0066] Here, the inductance value L of the inductor can preferably be a fixed value. In other embodiments, the proportional coefficient of the direct proportional relationship can be adjusted according to the inductance value, such as when the inductor current detection circuit further includes an inductor current acquisition circuit (in...). Figure 1 (Not shown in the diagram), the inductor current obtaining circuit pre-sets the inductance value to multiple different levels, or, during the off-state of the main switch, the inductor current obtaining circuit obtains the inductance value based on the input voltage, output voltage, and the inductor's current change rate. Those skilled in the art will know that, according to the volt-second product principle, there is a fixed formulaic relationship between the inductor's current change rate, inductance value, and input or output voltage. Therefore, based on this formula, knowing the inductor's current change rate and the input or output voltage, the inductor's inductance value can be obtained. Thus, 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 levels can be pre-set, and in practical applications, a suitable inductance value can be selected based on the chip in the circuit, which can also make the calculation of the ramp current more accurate.

[0067] Subsequently, the comparator CMP in the power converter receives the inductor current signal (which can be replaced by the corresponding inductor voltage signal V). IPK The system receives a comparison signal (such as a reference voltage signal Vref1) and a reference signal to obtain a comparison signal, which is used to control the switching state of the main switch in the power stage circuit. The logic and drive circuit 2 receives the comparison signal output by the comparator and a clock signal to output a switching signal to control the on / off state of the main switch based on the comparison signal and the clock signal.

[0068] As described above, the technical solution of this invention superimposes a ramp current signal representing the rise of the inductor current onto the sampled first current signal, and obtains the expected inductor current magnitude during the conduction period through virtual calculation. The first ramp current signal representing the rise of the inductor current in this invention is calculated based on the input and output voltages of the power topology, and can obtain a rising slope that is consistent with or substantially consistent with the actual inductor current. The inductor current detection circuit of this invention is unaffected by the conduction time or blanking time, can accurately obtain the magnitude of the inductor current, can broaden the range of input or output voltages of the power converter, and has a wide range of applications.

[0069] 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. In this embodiment... Figure 1 Based on the embodiment shown, an on-time detection circuit 3 is added (which can be, but is not limited to, controlled by a switch signal V). Q The circuit obtains conduction time information and an inductor current sampling circuit 4 (which can be, but is not limited to, obtained by connecting to one end of the inductor). The conduction time detection circuit 3 detects the conduction time Ton of the main switch. When the conduction time is less than or equal to a preset time value, where the preset time is the time when the inductor current can be accurately sampled, the superimposed inductor current signal I is selected. IPK1 (The corresponding voltage is expressed as V) IPK1 The current 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 to obtain the inductor current signal I. IPK2 (The corresponding voltage is expressed as V) IPK2 When the conduction time is greater than a preset time value, the inductor current signal I is selected to be switched on. IPK2 The data is transmitted to the subsequent circuitry. Here, the subsequent circuitry can be a comparator or other logic and control circuits, etc.

[0070] According to the circuit of this embodiment, if the conduction time of the main switch is short, the inductor current signal constructed in this way can be obtained without being limited by the conduction time, thus obtaining accurate inductor current information. If the conduction time of the main switch is long, there is no need to construct the inductor current information virtually, and the inductor current information can be obtained directly by sampling, resulting in a more realistic and accurate sampling signal.

[0071] The above embodiments use a 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 buck topology, boost topology, synchronous boost topology, flyback, synchronous flyback, and other suitable topologies. For example, in a boost topology, the rising inductor current is proportional to the input voltage during the conduction time of the main switch. Therefore, when constructing the ramp current signal, the current source is set to be proportional to the input voltage. In this way, an accurate inductor current signal can be obtained within one switching cycle.

[0072] refer to Figure 3 This is a circuit block diagram of a third embodiment of the inductor current detection circuit according to the present invention. In this embodiment, the power converter uses a buck topology circuit structure as an example. The topology is similar to... 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 during the conduction time to obtain the second current signal I. IPK (The corresponding voltage signal is represented as V) IPK During the turn-off time of the main switch, the ramp current construction circuit 1-2 constructs a second ramp current signal (the corresponding second ramp voltage signal is represented as V) that is proportional to the output voltage of the power converter based on the topology of the power converter. COMP The subtraction circuit 1-3 receives the peak voltage signal V. IPK and the ramp voltage signal V COMP Subtraction is performed to obtain the inductor current signal of the main switch transistor during one switching cycle.

[0073] Here, the second ramp voltage signal V COMP The proportionality coefficient K is directly proportional to the output voltage Vout of the power converter. This proportionality is inversely proportional to the inductance value L of the inductor. Similarly, the inductance value L can preferably be a fixed value. In other embodiments, the proportionality coefficient can be adjusted based on the inductance value, such as when the inductor current detection circuit further includes an inductor current acquisition circuit (in...). Figure 3(Not shown in the diagram), the inductor current obtaining circuit pre-sets the inductance value of the inductor to multiple different levels, or, during the conduction time of the main switch, the inductor current obtaining circuit obtains the inductance value based on the input voltage, output voltage, and the rate of change of the inductor current. Those skilled in the art will know that, according to the volt-second product principle of circuits, there is a fixed formulaic relationship between the rate of change of the inductor current, the inductance value, and the input or output voltage. Therefore, according to the formula, knowing the rate of change of the inductor current, the input voltage, and the output voltage, the inductance value can be obtained. Thus, different control chips can obtain different inductance values, thereby obtaining a corresponding accurate proportional system, making the calculation of the ramp current more accurate.

[0074] The ramp 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 charges the charging capacitor, and the voltage signal across the charging capacitor is a second ramp voltage signal characterizing the second ramp current signal. The magnitude of the current source is directly proportional to the output voltage of the power converter. The switching state of the first switch is the same as the switching state of the main switch. During the off-time of the main switch, the charging capacitor is charged until the off-time ends; during the on-time of the main switch, the charging capacitor is discharged to zero. The ramp current reconstruction circuit in this embodiment is similar to... Figure 1 The structure is similar to that in (a), except that the switching state of the first switch is the same as... Figure 1 Conversely to (a), according to the circuit structure and control relationship in this embodiment, during the main switch's off-state period, the charging capacitor is charged by the current source, and the current of the current source is set to be proportional to the output voltage. Therefore, the resulting second ramp voltage signal is proportional to the output voltage. For the buck circuit, during the main switch's off-state period, the inductor current decreases, and the magnitude of this decrease is proportional to the output voltage. Therefore, the constructed second ramp voltage signal V... COMP This can characterize the magnitude of the decreasing inductor current. It is achieved by sampling the inductor current signal at the end of the conduction time and subtracting the ramp voltage signal V. COMP The magnitude of the inductor current during the turn-off time can be obtained. Thus, according to the circuit scheme of this embodiment, when the turn-off time of the main switch is short, the constructed inductor current signal can obtain accurate inductor current information without being limited by the turn-off time.

[0075] In summary, this embodiment of the invention samples the inductor current information during the on-time or off-time of the main switch using a current sampling circuit. Then, a ramp current construction circuit constructs a ramp current signal proportional to the power converter's input voltage, output voltage, or a combination of both, based on the power converter's topology. The calculation circuit receives the inductor current signal and the ramp current signal, performing superposition or subtraction to obtain the inductor current information within one switching cycle. This technical solution is not limited by the blanking time or switching time of the main switch; the power converter can adjust the input or output voltage range as needed, making it widely applicable.

[0076] Finally, as Figure 4 As shown, this invention discloses an inductor current detection method applied in a power converter, the power converter including a connected main switch transistor and an inductor, comprising the following steps:

[0077] S1: Sample the inductor current information of the main switch during the on-time or off-time period to obtain the inductor current signal;

[0078] S2: Based on the topology of the power converter, construct a ramp voltage signal that is proportional to the input voltage or output voltage or the input voltage and the input voltage after calculation.

[0079] S3: Receive the inductor current signal and the ramp voltage signal, and perform calculations to obtain the inductor current signal of the main switch in one switching cycle.

[0080] Further includes: sampling the inductor current information of the main switch during the turn-off time to obtain a first current signal during the turn-off time;

[0081] During the conduction time of the main switch, a first ramp current signal is constructed based on the topology of the power converter and is directly proportional to the input voltage or the difference between the input voltage and the output voltage of the power converter.

[0082] The first current signal and the first ramp current signal are received and superimposed to obtain the inductor current signal of the main switch in one switching cycle.

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

[0084] Furthermore, the proportionality coefficient of the direct proportional relationship is adjusted according to the inductance value of the inductor.

[0085] Furthermore, the inductance value of the inductor is preset to multiple different levels, or...

[0086] During the turn-off time of the main switch, the inductance value is obtained based on the input voltage, the output voltage, and the rate of change of the inductor current.

[0087] Further, it includes: sampling the inductor current information of the main switch during the conduction time to obtain a second current signal during the conduction time;

[0088] During the turn-off time of the main switch, a second ramp current signal that is proportional to the output voltage of the power converter is constructed based on the topology of the power converter.

[0089] The second current signal and the second ramp current signal are received and subtracted to obtain the inductor current signal of the main switch in one switching cycle.

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

[0091] Furthermore, the proportionality coefficient of the direct proportional relationship is adjusted according to the inductance value of the inductor.

[0092] Furthermore, the inductance value of the inductor is preset to multiple different levels, or...

[0093] During the conduction time of the main switch, the inductance value is obtained based on the input voltage, the output voltage, and the rate of change of the inductor current.

[0094] Finally, this invention discloses a power converter. The aforementioned inductor current detection circuit further includes a power stage circuit, a comparator circuit, and logic and drive circuits.

[0095] The inductor current detection circuit is used to obtain the inductor current signal within one switching cycle.

[0096] The comparator circuit receives the inductor current signal and a reference signal to obtain a comparison signal, which is used to control the switching state of the main switch in the power stage circuit.

[0097] The logic and drive circuit receives a comparison signal and a clock signal output by the comparator, and outputs a switching signal to control the on / off state of the main switch transistor based on the comparison signal and the clock signal.

[0098] Similarly, the power converter described above can adjust the width range of the input and output signals according to requirements, making it widely applicable.

[0099] The embodiments described above do not constitute a limitation on the scope of protection of this technical solution. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the above embodiments should be included within the scope of protection of this technical solution.

Claims

1. An inductor current detection circuit, applied in a power converter, the power converter comprising a main switching transistor and an inductor connected to each other, characterized in that, include, A current sampling circuit is used to sample the current information of the inductor to obtain the inductor current signal of the main switch during the on-time or off-time. The ramp current construction circuit obtains a ramp current signal that is proportional to the inductor's current change rate and the inductor's inductance value and the input voltage or output voltage, or the input voltage and output voltage, based on the topology of the power converter. The arithmetic circuit receives the inductor current signal and the ramp current signal, and performs arithmetic processing to obtain the inductor current signal within one switching cycle. The current sampling circuit samples the inductor current information of the main switch during the conduction time to obtain the second current signal; During the turn-off time of the main switch, 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. The operational 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 one switching cycle of the main switch.

2. The inductor current detection circuit according to claim 1, characterized in that, The proportionality coefficient of the direct proportional relationship is inversely proportional to the inductance value.

3. The inductor current detection circuit according to claim 1, characterized in that, The proportionality 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, characterized in that, It also includes an inductance value acquisition circuit, which pre-sets the inductance value of the inductor to multiple different range values, or... During the conduction time of the main switch, the inductance value acquisition circuit obtains the inductance value based on the input voltage, the output voltage, and the rate of change of the inductor current.

5. An inductor current detection method, applied in a power converter, the power converter including a main switching transistor and an inductor connected together, characterized in that, Including the following steps: S1: Sample the inductor current information of the main switch during the on-time or off-time period to obtain the inductor current signal; S2: Based on the topology of the power converter, obtain a ramp current signal that is proportional to the inductor's current change rate and the inductor's inductance value and the input voltage or output voltage, or the input voltage and output voltage after calculation. S3: Receive the inductor current signal and the ramp current signal, and perform calculations to obtain the inductor current signal of the main switch in one switching cycle; The inductor current information of the main switch during the conduction time is sampled to obtain the second current signal during the conduction time; During the turn-off time of the main switch, a second ramp current signal that is proportional to the output voltage of the power converter is constructed based on the topology of the power converter. The second current signal and the second ramp current signal are received and subtracted to obtain the inductor current signal of the main switch in one switching cycle.

6. The inductor current detection method according to claim 5, characterized in that, The proportionality coefficient of the direct proportional relationship is inversely proportional to the inductance value.

7. The inductor current detection method according to claim 5, characterized in that, The proportionality coefficient of the direct proportional relationship is adjusted according to the inductance value of the inductor.

8. The inductor current detection method according to claim 7, characterized in that, The inductance value is preset to multiple different levels, or... During the conduction time of the main switch, the inductance value is obtained based on the input voltage, the output voltage, and the rate of change of the inductor current.

9. A power converter, characterized in that, The circuit includes the inductor current detection circuit according to any one of claims 1-4, and further includes a power stage circuit, a comparator circuit, and logic and drive circuits. The inductor current detection circuit is used to obtain the inductor current signal within one switching cycle. The comparator circuit receives the inductor current signal and a reference signal to obtain a comparison signal, which is used to control the switching state of the main switch in the power stage circuit. The logic and drive circuit receives a comparison signal and a clock signal output by the comparison circuit, and outputs a switching signal to control the on / off state of the main switch transistor based on the comparison signal and the clock signal.

Images