Current detection circuit of coupling inductor

Abstract

The invention provides a current detection circuit comprising a coupling inductor which comprises a first winding and a second winding; a first resistor; a first capacitor comprising a first side connected in series with the first resistor, where the first resistor and the first capacitor are connected in parallel with the first winding, and a second side connected with the outputs of the first and second windings; a second resistor; the second capacitor comprises a first side connected with the second resistor in series, the second resistor and the second capacitor are connected with the second winding in parallel, and the second side is connected with the output ends of the first winding and the second winding; and the third capacitor comprises a first side connected between the first resistor and the first capacitor and a second side connected between the second resistor and the second capacitor. A first voltage across the first capacitor indicates a first current flowing through the first winding, and a second voltage across the second capacitor indicates a second current flowing through the second winding.

Description

Technical Field

[0001] The present disclosure relates to methods and systems for current sensing in circuits containing coupled inductors. Background Art

[0002] Electronic systems often include power conversion systems. These power conversion systems can increase, decrease, regulate or otherwise control the voltage and / or current levels in the electronic system. With appropriate power conversion technology, discrete electrical components can be integrated and multiple loads can be powered by a single power supply while operating at different power levels.

[0003] Coupled inductors (e.g., electronic devices that include one or more windings coupled to a shared magnetic core) can be used as part of a power conversion system. In such a system, the configuration of the coupled inductor can affect the power conversion operations available to the system. For example, the turns ratio between the windings of the coupled inductor can determine the amount of power amplification that occurs between the windings. Coupled inductors are widely used in a variety of electronic systems due to their high efficiency, small size, and ability to maintain their power conversion performance in high-frequency applications.

[0004] During operation of the coupled inductor, current may be controlled to repeatedly flow through each winding of the coupled inductor (each winding may correspond to a phase). Based on these controls, a characteristic current waveform may appear to flow through a winding during an operating phase of the coupled inductor, and the current flowing through a first phase may be offset in time relative to the current flowing through other phases. For example, in an N-phase coupled inductor, where N is the number of phases, each individual current waveform may be offset in time by a duty cycle divided by N (or equivalently 360 degrees divided by N), where the duty cycle may be equal to the inverse of the frequency of the characteristic current waveform.

[0005] When controlling current through coupled inductors, especially at high frequency operation, it can be a challenge to continuously and accurately monitor the current flowing through each phase. The accuracy limitations of this current monitoring can hinder adequate control of the power conversion system and protection of components located in or connected to the power conversion system. Therefore, it is desirable to continuously detect accurate information about the current flowing through the coupled inductors. Summary of the invention

[0006] The present disclosure provides a circuit for detecting current in an electronic system including one or more coupled inductors. The circuit disclosed herein can improve the operating capabilities of a system including coupled inductors, such as a system used for power conversion or other suitable applications.

[0007] According to some embodiments of the present disclosure, a current detection circuit includes a coupled inductor including a first winding and a second winding; a first resistor; a first capacitor including a first side connected in series with the first resistor, wherein the first resistor and the first capacitor are connected in parallel with the first winding, and a second side connected with the second capacitor; a second resistor, the second capacitor including a first side connected in series with the second resistor, wherein the second resistor and the second capacitor are connected in parallel with the second winding, and a second side connected with the first capacitor, wherein the second resistor and the second capacitor are connected in parallel with the second winding; and a third capacitor including a first side connected between the first resistor and the first capacitor, and a second side connected between the second resistor and the second capacitor. A first voltage across the first capacitor indicates a first current flowing through the first winding, and a second voltage across the second capacitor indicates a second current flowing through the second winding.

[0008] In some embodiments, the circuit further includes a third resistor connected in series with the third capacitor, wherein the third resistor changes the time constant of the coupled inductor.

[0009] In some embodiments, the circuit further comprises at least one third resistor connected in parallel with at least one of the first capacitor, the second capacitor or the third capacitor, wherein the at least one third resistor scales at least one of the first or second voltage.

[0010] In some embodiments, the circuit further includes a plurality of switches to control current flowing through the first and second windings.

[0011] In some embodiments, the plurality of switches includes first and second switches connected in series and third and fourth switches connected in series, wherein the first winding is connected between the first and second switches and the second winding is connected between the third and fourth switches.

[0012] In some embodiments, the output ends of the first and second windings are connected, and the circuit further includes a third winding, wherein a first side of the third winding is connected in series with the connected output ends of the first and second windings, and a second side of the third winding is connected between the first and second capacitors.

[0013] In some embodiments, the output terminals of the first and second windings are connected, and the circuit further includes N-2 windings, wherein N corresponds to the number of phases of the coupled inductor, each of the N-2 windings corresponding to a respective phase and having an output terminal connected to the connected output terminals of the first and second windings; N-2 phase resistors, each corresponding to a respective phase; N-2 phase capacitors, each corresponding to a respective phase and including a first side connected in series with a respective one of the N-2 phase resistors, wherein one of each set of phase resistors and one of the N-2 phase capacitors are connected in parallel with a respective one of the N-2 windings, and a second side connected to the connected output terminals of the first and second windings; and (N-1)!-1 coupling capacitors, each of the (N-1)!-1 coupling capacitors including a first side connected between a respective first phase resistor and a respective first phase capacitor, and a second side connected between a respective second phase resistor and a respective second phase capacitor.

[0014] According to some embodiments of the present disclosure, a current detection circuit includes a coupled inductor including N windings, wherein N corresponds to the number of phases of the coupled inductor, the N windings having connected output terminals; N first resistors; N first capacitors, each of the first capacitors including a first side connected in series with a corresponding first resistor, wherein the respective first resistor and the respective first capacitor are connected in parallel with one of the N windings, and a second side connected to the connected output terminals of the N windings; N first amplifiers, wherein the first input terminal of each first amplifier is connected between the respective first resistor and the respective first capacitor, and the second input terminal of each first amplifier is connected to the connected output terminals of the N windings; and a second amplifier, wherein the first input terminal of the second amplifier is connected to the connected output terminals of the N windings, and the second input terminal of the second amplifier is connected to a common node. Each input terminal of each corresponding winding is connected in series with a corresponding one of the N second resistors, each of the N second resistors is further connected to the common node, and the respective sum of the output voltage of each of the N first amplifiers and the output voltage of the second amplifier indicates the current flowing through the respective windings of the N windings.

[0015] In some embodiments, the circuit further includes N third resistors, wherein each of the N third resistors is connected in parallel with a corresponding one of the N first capacitors, and each of the N third resistors scales a voltage at the second input terminal of each first amplifier.

[0016] In some embodiments, the circuit further includes a plurality of switches to control current flowing through the N windings.

[0017] In some embodiments, the plurality of switches includes N pairs of first and second switches, wherein each pair of first and second switches are connected in series, and each winding is connected between a corresponding pair of first and second switches.

[0018] In some embodiments, the circuit further includes a third capacitor including a first side connected to the common node and a second side connected to the connected output terminals of the N windings.

[0019] According to some embodiments of the present disclosure, a current detection circuit includes a first coupled inductor including a first input winding and a first output winding; a second coupled inductor including a second input winding and a second output winding, wherein the first output winding is connected in series with the second output winding; first and second resistors; a first capacitor including a first side connected in series with the first resistor and in parallel with the second resistor, and a second side connected in series with the first input winding; third and fourth resistors; a second capacitor including a first side connected in series with the third resistor and in parallel with the fourth resistor, and a second side connected in series with the second input winding; a third inductor connected in series with the first and second output windings; a fifth and sixth resistor connected in series; and a third capacitor including a first side connected between the fifth and sixth resistors, and a second side connected between the second output winding and the third inductor. A difference between a first voltage across the first capacitor and a detection voltage across the third capacitor indicates a first current flowing through the first coupled inductor, and a difference between a second voltage across the second capacitor and a detection voltage across the third capacitor indicates a second current flowing through the second coupled inductor.

[0020] In some embodiments, the circuit further includes a plurality of switches to control current flowing through the first and second windings.

[0021] In some embodiments, the plurality of switches include first and second switches connected in series and third and fourth switches connected in series, the first input winding is connected between the first and second switches, and the second input winding is connected between the third and fourth switches.

[0022] In some embodiments, the circuit further includes N-2 coupled inductors, each coupled inductor including a respective input winding and a respective output winding, wherein N corresponds to the number of phases of the coupled inductors, and the respective output windings of the N-2 coupled inductors are connected in series; 2N-4 resistors, wherein each of the N-2 coupled inductors is connected to a respective two of the 2N-4 resistors; and N-2 capacitors, wherein each of the N-2 coupled inductors is connected to a respective one of the N-2 capacitors, and each of the N-2 capacitors includes a first side connected in series with a first resistor of the respective two of the 2N-4 resistors and connected in parallel with a second resistor of the respective two of the 2N-4 resistors, and a second side connected in series with a respective input winding of one of the N-2 coupled inductors. The current flowing through each of the N-2 coupled inductors is indicated by the difference between the voltage across the respective one of the N-2 capacitors and the detection voltage.

[0023] The current detection circuit includes a first coupled inductor including a first input winding and a first output winding; a second coupled inductor including a second input winding and a second output winding, wherein the first output winding is connected in series with the second output winding; first and second DrMOS (driving MOSFET) modules to control the current flowing through the first and second coupled inductors, wherein the first output terminals of the first and second DrMOS blocks are connected in series with the first and second input windings, respectively; a first capacitor including a first side connected in series with the second output terminal of the first DrMOS module, and a second side connected to a first reference voltage; a second capacitor including a first side connected in series with the second output terminal of the second DrMOS module, and a second side connected to a second reference voltage; first and second resistors connected in parallel with the first and second capacitors, respectively; a third inductor connected in series with the first and second output windings; a third resistor and a third capacitor connected in series between the first and second output terminals of the first DrMOS module; a fourth resistor and a fourth capacitor connected in series between the first and second output terminals of the second DrMOS module; and a fifth capacitor including a first side connected in series with the fifth resistor and in parallel with the sixth resistor, and a second side connected between the second output winding and the third inductor. The difference between the voltage across the first capacitor and the voltage across the fifth capacitor indicates a first current flowing through the first coupled inductor, and the difference between the voltage across the second capacitor and the voltage across the fifth capacitor indicates a second current flowing through the second coupled inductor.

[0024] In some embodiments, the circuit further includes a control circuit to control the first and second DrMOS modules, wherein the first and second output terminals of the control circuit are respectively connected to the first side and the second side of the first capacitor, and the third and fourth output terminals of the control circuit are respectively connected to the first side and the second side of the second capacitor.

[0025] In some embodiments, the circuit further includes a fifth resistor connected in parallel with the first capacitor, wherein the fifth resistor scales a first voltage across the first capacitor; and a sixth resistor connected in parallel with the second capacitor, wherein the sixth resistor scales a second voltage across the second capacitor.

[0026] In some embodiments, the circuit further includes N-2 coupled inductors, where N corresponds to the number of phases of the coupled inductors, each coupled inductor includes an input winding and an output winding, and the output winding of the N-2 coupled inductors is connected in series with the first and second output windings; N-2 DrMOS modules, each of the N-2 DrMOS modules corresponds to a respective phase and is configured to control a current flowing through one of the N-2 coupled inductors; and 2N-4 resistors and 2N-4 capacitors, where two resistors in each group of 2N-4 resistors and two capacitors in each group of 2N-4 capacitors correspond to a respective phase, and the first of the two resistors and the first of the two capacitors are connected in parallel with the first output terminal of the corresponding DrMOS module and the corresponding reference voltage; the second of the two resistors and the second of the two capacitors are connected in series with the first and second output terminals of the corresponding DrMOS module, where the difference between the voltage across the first of the two capacitors and the voltage across the fifth capacitor indicates the current flowing through the corresponding coupled inductor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The following description includes a discussion of the accompanying drawings, which have descriptions given by way of examples of implementations of the embodiments of the present disclosure. These drawings should be understood by way of example, not as limitations. One or more "embodiments" used herein should be understood to describe specific features, structures, and / or characteristics included in at least one embodiment. Therefore, phrases such as "in some embodiments" appearing herein describe at least one embodiment and implementation method, and do not necessarily all refer to the same embodiment. However, they are not necessarily mutually exclusive.

[0028] Figure 1 A two-phase coupled inductor connected to a current sensing circuit according to some embodiments of the present disclosure is shown;

[0029] Figure 2 A two-phase coupled inductor connected to an output winding and a current sensing circuit according to some embodiments of the present disclosure is shown;

[0030] Figure 3 A three-phase coupled inductor connected to a current detection circuit according to some embodiments of the present disclosure is shown;

[0031] Figure 4 A multi-phase coupled inductor connected to an output amplifier and a current sensing circuit according to some embodiments of the present disclosure is shown;

[0032] Figure 5 A plurality of transformer inductors for voltage regulator (TLVR) circuits and current sensing circuits according to some embodiments of the present disclosure are shown;

[0033] Figure 6 A first circuit including a plurality of TLVRs and a driver MOSFET (DrMOS) circuit and a current detection circuit according to some embodiments of the present disclosure is shown;

[0034] Figure 7 A second circuit including a plurality of TLVR and DrMOS circuits and a current sensing circuit according to some embodiments of the present disclosure is shown;

[0035] Figure 8 A third circuit including a plurality of TLVR and DrMOS circuits and a current detection circuit according to some embodiments of the present disclosure is shown;

[0036] Fig. 9 A fourth circuit including a plurality of TLVR and DrMOS circuits and a current sensing circuit according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0037] According to some embodiments of the present disclosure, a circuit for detecting a current flowing through a coupled inductor is provided. The detection circuit includes one or more resistor-capacitor (RC) networks, which are connected in parallel to the winding through which the current needs to be detected. Various detection circuits can be implemented by integrating this basic structure with other electrical devices that support power conversion and / or detection operations. For a given detection circuit, a signal at a specific node of the circuit is provided to identify the current flowing through the corresponding winding. In some embodiments, the voltage is directly detected at a specific node of the circuit, and the current flowing through each winding can be determined based on the detected voltage. For example, the current flowing through each winding can be equal to a voltage (for example, a voltage detected and indicating the current) divided by a known resistance (for example, the resistance of the corresponding winding). This current flow amplitude can be configured by a gain resistor, which can be configured by a resistor, an amplifier, a capacitor and / or other elements of the circuit (for example, by adding, removing, reconfiguring or resizing the above elements).

[0038] The detection circuits provided herein can operate in a coupled inductor system of two or more phases (e.g., three or more phases). In some embodiments, a switch circuit is provided to control the current flowing through the corresponding winding. In some embodiments, a resistor and / or an amplifier (e.g., an operational amplifier or other suitable amplifier) ​​is provided to scale the voltage signal (e.g., by adjusting the gain resistor) to support current detection. In some embodiments, the coupled inductor system includes a transformer inductor for a voltage regulator (TLVR) circuit or a TLVR and a driver MOSFET (DrMOS) circuit.

[0039] Figure 1 A circuit 100 including a two-phase coupled inductor connected to a current sensing circuit is shown according to some embodiments of the present disclosure. The circuit 100 includes an input terminal 102 and an output terminal 104, as well as a winding 114 and a winding 116. The output terminals of the winding 114 and the winding 116 are connected to each other and to the output terminal 104. The circuit 100 includes a switch 106 and a switch 108, which can control the current flowing through the winding 114; and a switch 110 and a switch 112, which can control the current flowing through the winding 116. The winding 114 and the winding 116 are coupled (e.g., by a shared magnetic core) and thus collectively represent a two-phase coupled inductor of the circuit 100. A first series RC path is connected in parallel with the winding 114 and includes a resistor 118 and a capacitor 120. A second series RC path is connected in parallel with the winding 116 and includes a resistor 122 and a capacitor 124. Circuit 100 further includes capacitor 126 (e.g., coupling capacitor) including a first side connected between resistor 118 and capacitor 120, and a second side connected between resistor 122 and capacitor 124. In some embodiments, capacitor 126 may affect transient characteristics (e.g., time constant) of circuit 100. For example, capacitor 126 may affect the detection response speed of capacitor 120 and capacitor 124, or may affect the coupling between winding 114 and winding 116.

[0040] In some embodiments, operation of circuit 100 includes repeated switching of at least switch 106 and switch 110. When switch 106 is in an on state, a controlled current may flow through winding 114, and when switch 110 is in an on state, a controlled current may flow through winding 116. In some embodiments, switch 106 and switch 110 are controlled so that no switch is in an on state at the same time (e.g., when switch 106 is off, switch 110 is on, and vice versa). It should be understood that based on the inductive characteristics of winding 114 and winding 116 and the coupling characteristics of these windings, the windings may still be conductive even when their respective current control switches are in an off state. Therefore, after an initial startup period, switch 106 may be opened to increase the current flowing through winding 114, and then may be closed to reduce (but not to zero) the current flowing through winding 114; the same may be true for switch 110 and winding 116. In some embodiments, operation of a single phase may include opening a switch to increase the current through the winding until a maximum value is reached, and then closing the switch to decrease the current through the winding until a minimum value is reached.

[0041] During operation of the circuit 100, the phase currents flowing through the windings 114 and 116 can be detected based on the voltages detected across the capacitors 120 and 124, respectively. Based on the characteristics of the first and second series RC paths and the capacitor 126, the voltages detected across the capacitors 120 and 124 can indicate the currents flowing through the windings 114 and 116. For example, the phase current flowing through the winding 114 multiplied by the series resistance of the winding 114 can be equal to the voltage across the capacitor 120. In some embodiments, the gain (e.g., amplification or reduction) of the phase current flowing through the winding 114 can be configured by the resistor 118 and / or other resistive elements in the circuit 100. Similarly, the phase current flowing through the winding 116 multiplied by the series resistance of the winding 116 can be equal to the voltage across the capacitor 124. In some embodiments, the gain of the phase current flowing through the winding 116 can be configured by the resistor 122 and / or other resistive elements in the circuit 100. In some embodiments, these phase currents are detected with a fast response time. For example, when operating at a switching frequency of 200 kHz or higher (e.g., the switching frequency of switch 106 and switch 110), the sense voltage can accurately sense the current flowing through the windings of circuit 100. Based on the accurate detection of the current flowing through winding 114 and winding 116, circuit 100 can be operated accurately at high speed without the risk of damaging the components shown in circuit 100 or other components connected thereto.

[0042] In some embodiments, additional resistors may be included in circuit 100. In particular, additional resistors may be connected in parallel with any one or more of capacitors 120, 124, or 126. These additional resistors may scale (e.g., increase or decrease) the amplitude of the detected voltage signal, or may affect the transient characteristics (e.g., time constant) of the detected voltage signal. For example, a resistor connected in parallel with capacitor 120 may scale the voltage signal that may be detected across capacitor 120, and a resistor connected in parallel with capacitor 124 may scale the voltage signal that may be detected across capacitor 124. A resistor connected in parallel with capacitor 126 may affect the time constant or other transient characteristics of circuit 100.

[0043] In some embodiments, switches 106, 108, 110, and 112 may be MOSFETs (e.g., n-type MOSFETs), as shown in circuit 100. It should be understood that other switch devices (e.g., using p-type MOSFETs, any other suitable switch devices, or combinations thereof) or switch configurations (e.g., having different coupling paths to winding 114 and winding 116) may also similarly enable circuit 100 and its related embodiments to operate. When circuit 100 operates, switches 106, 108, 110, and 112 may be switched at a specific switching frequency and phase offset (i.e., time offset) so that a controlled current (including a desired current maximum and minimum) may flow through winding 114 and winding 116. In some embodiments, switch 106 and switch 108 operate in pairs, such that switch 108 is turned on after switch 106 is turned off; switch 110 and switch 112 similarly operate in pairs. In some embodiments, switch 110 and switch 112 operate in pairs to switch switches after the pair of switches 106 and switch 108 have operated to switch switches. For example, a single duty cycle of circuit 100 may include sequentially switching each of switches 106, 108, 110, and 112. It should be understood that these switching schemes are merely exemplary and that the switches may be operated in any desired manner without departing from the teachings of the present disclosure.

[0044] Figure 2A circuit 200 including a two-phase coupled inductor connected to an output winding and a current sensing circuit according to some embodiments of the present disclosure is shown. In the circuit 200, components 202, 204, 206, 208, 210, 212, 214, 216, 218, 220, 222, 224, and 226 may correspond to components 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, and 126, respectively, in some embodiments. Compared to the circuit 100, the circuit 200 includes an additional winding 230. The input end of the winding 230 is connected to the connected output ends of the winding 214 and the winding 216, and the output end of the winding 230 is connected to the output end 204 of the circuit 200. The phase current in the circuit 200 may be detected according to the steps described above for detecting the phase current in the circuit 100 (eg, based on corresponding components).

[0045] Figure 3 A circuit 300 including a three-phase coupled inductor connected to a current sensing circuit according to some embodiments of the present disclosure is shown. In the circuit 300, components 302, 304, 306, 308, 310, 312, 314, 316, 318, 320, 322, 324, and 326 may correspond to components 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, and 126, respectively, in some embodiments. Compared to the circuit 100, the circuit 300 includes an additional pair of switches 311 and 313, an additional winding 317, an additional series RC path connected in parallel with the winding 317 (the additional RC path includes a resistor 323 and a capacitor 325), and additional capacitors 330 and 332. As shown by the dashed curves and arrows, windings 314, 316, and 317 are coupled (e.g., by sharing a magnetic core) to achieve a three-phase coupled inductor. It should be understood that although three phases are shown in circuit 300, these teachings can be extended to multi-phase circuits with any number of coupled inductors or phases of three or more. Just as elements 311, 313, 317, 323, 325, 330, and 332 are added to two-phase circuit 100 to achieve three-phase circuit 300, similar elements can be added to circuit 300 to achieve four or more phase circuits using the teachings herein.

[0046] During operation of circuit 300, the voltage detected across capacitors 320, 324, and 325 can indicate the phase current flowing through windings 314, 316, and 317, respectively. For example, each of these respective phase currents multiplied by its respective winding series resistance can be equal to the respective voltage across each of these respective capacitors. In some embodiments, the gain of these phase currents can be configured based on the size of the resistors connected to the windings (e.g., based on resistors 318, 322, or 323, respectively, and / or other resistive elements in circuit 300).

[0047] Considering the operation of the first pair of switches 106 and 108 (e.g., as corresponding to switches 306 and 308) and the operation of the second pair of switches 110 and 112 (e.g., as corresponding to switches 310 and 312), the third pair of switches 311 and 313 can operate in a similar manner. For example, in a given duty cycle, the first, second, and third pairs of switches in the circuit 300 can be switched in sequence, and during the operation of the third pair of switches, the switch 311 can be closed before the switch 313 is turned on. Therefore, amplitude-controlled and phase-controlled currents can be driven through the windings 314, 316, and 317.

[0048] Capacitor 330 couples together an RC path including resistor 318 and capacitor 320 and an RC path including resistor 323 and capacitor 325. Capacitor 332 couples together an RC path including resistor 322 and capacitor 324 and an RC path including resistor 323 and capacitor 325. In circuit 300, the connection of capacitors 326, 330, and 332 results in each respective RC path connected in parallel with the respective winding being connected to all other RC paths connected in parallel with the winding. For a three-phase coupled inductor (N=3), three capacitors or equivalently (N-1)! capacitors are implemented to achieve connection between each combination of two respective RC paths connected in parallel with the windings of the coupled inductor. For any multi-phase circuit extended from circuit 300, in addition to at least the capacitors of each RC path, (N-1)! capacitors (e.g., coupling capacitors) may be included. These (N-1)! The capacitors may be arranged such that each RC path connected in parallel with one winding of the N-phase coupled inductor is directly connected to all other RC paths connected in parallel with one winding of the N-phase coupled inductor.

[0049] In some embodiments, additional resistors may be included in the circuit 300. Specifically, the additional resistors may be connected in parallel with any one or more of the capacitors 320, 324, 325, 326, 330, or 332. These additional resistors may scale (e.g., increase or decrease) the amplitude of the detection voltage signal, or may affect the transient characteristics (e.g., time constant) of the detection voltage signal. For example, a resistor connected in parallel with any one or more of the capacitors 320, 324, or 325 may scale the voltage signal that may be detected across these capacitors. For example, a resistor connected in parallel with any one or more of the capacitors 326, 330, or 332 may affect the time constant or other transient characteristics of the circuit 300.

[0050] Figure 4 A circuit 400 including a multi-phase coupled inductor connected to an output amplifier and a current sensing circuit according to some embodiments of the present disclosure is shown. In circuit 400, elements 402, 404, 406, 408, 410, 411, 412, 413, 414, 416, 417, 418, 420, 422, 423, 424, and 425 may correspond to elements 302, 304, 306, 308, 310, 311, 312, 313, 314, 316, 317, 318, 320, 322, 323, 324, and 325, respectively, in some embodiments. As shown by the dashed curves and arrows, windings 414, 416, and 417 are coupled (e.g., by sharing a magnetic core) to achieve a three-phase coupled inductor. Compared to circuit 300, circuit 400 additionally includes a series of amplifiers with gain A1, including amplifiers 446, 447, and 448, each corresponding to a respective phase. Circuit 400 also additionally includes amplifier 450 with gain A2, resistors 438, 440, and 442, capacitor 444, and voltage adders 452 and 454. Circuit 400 can be expanded to more than three phases, as shown by “■■■”, where each additional phase can include an additional winding connected to a repeated accumulation circuit element shown in module 460.

[0051] exist Figure 4 and other locations, although the wires are not shown as physically touching (for simplicity and clarity of the drawing), gray circles surrounded by solid lines and filled with white diagonal cross lines represent nodes that are connected to each other. Figure 4 At other locations, the gray circles surrounded by dashed lines represent reference nodes. It should be understood that when voltages are detected at these reference nodes, the voltages are detected relative to a common voltage (eg, ground level or other suitable reference voltage).

[0052] Thus, circuit nodes 432, 434 and 436 connect windings 414, 416 and 417 in parallel with resistors 438, 440 and 442, respectively. A pair of parallel paths are provided across these resistors, which are connected to capacitor 444 and a first input of amplifier 450, respectively. The other side of capacitor 444 is connected to the outputs of windings 414, 416 and 417 (these windings are coupled) and to a second input of amplifier 450 (the input is connected to the outputs of the windings). A second input node of amplifier 450 is also connected to a first input of each amplifier 446, 447 and 448. A second input of each amplifier 446, 447 and 448 is connected between the resistance and capacitance of a respective RC path, which is connected in parallel with the winding having a corresponding phase with the respective amplifier 446, 447 or 448.

[0053] During operation of the circuit 400, the winding current flowing through each phase can be detected based on the output provided by the voltage adder corresponding to the phase. For example, the phase current flowing through the winding 414 can be indicated by the output of the voltage adder 452 at the node 456, the phase current flowing through the winding 416 can be indicated by the output of the voltage adder 455 at the node 459, and the phase current flowing through the winding 417 can be indicated by the output of the voltage adder 454 at the node 458. For example, each of these corresponding phase currents multiplied by the corresponding winding series resistance can be equal to the corresponding voltage at the output of each of these corresponding adders. In some embodiments, the gain of these phase currents can be configured based on the characteristics of these amplifiers (e.g., based on the configurable gain A1 of the amplifier 446, 447 or 448, respectively) and / or the size of the resistor connected to the winding (e.g., based on the resistor 418, 422 or 423, respectively, and / or the resistive element in the circuit 400). Additionally, modifying one or both of gains A1 and A2 can scale the voltage detected at the output of each of these voltage summers.

[0054] Output 404 of circuit 400 may be connected in parallel with (i) each winding 414, 416, and 417, (ii) a first input of each amplifier 446, 447, and 448, and (iii) a second input of amplifier 450. In some embodiments, a load may be connected to output 404.

[0055] Figure 5A circuit 500 including a plurality of coupled inductors connected to a transformer inductor for a voltage regulator (TLVR) circuit and a current sensing circuit according to some embodiments of the present disclosure is shown. In circuit 500, elements 502, 504, 506, 508, 510, 511, 512, 513, 514, 516, 517, 518, 520, 522, 523, 524, and 525 may correspond to elements 402, 404, 406, 408, 410, 411, 412, 413, 414, 416, 417, 418, 420, 422, 423, 424, and 425, respectively, in some embodiments. Instead of including only one winding per phase (e.g., as in circuits 100, 200, 300, and 400), circuit 500 includes one coupled inductor for each phase, each coupled inductor including a pair of coupled input and output windings. In particular, circuit 500 includes at least input windings 514, 516, and 517, each of which is coupled to output windings 530, 531, and 532, respectively (e.g., through a corresponding magnetic core). Input windings 514, 516, and 517 are connected in parallel, and output windings 530, 531, and 532 are connected in series. Circuit 500 also includes winding 546, which is connected between output terminal 504 and output winding 532. Winding 546 is connected in parallel with the paths of windings 530, 531, and 532. Winding 546 is also connected in parallel with a path including resistor 544 connected in series with a parallel RC combination including capacitor 540 and resistor 542. Circuit 500 may be extended to more than three phases, as indicated by "■■■", where each additional phase may include a repetition of the cumulative circuit elements shown in block 560 and corresponding connections.

[0056] During operation of the circuit 500, the current flowing through each corresponding coupled inductor can be detected based on at least the voltage at nodes 550, 552, 554, and 556. For example, the phase current flowing through the winding 514 can be indicated by the difference between the voltage at node 550 and the voltage at node 556; the phase current flowing through the winding 516 can be indicated by the difference between the voltage at node 552 and the voltage at node 556; the phase current flowing through the winding 517 is indicated by the difference between the voltage at node 554 and the voltage at node 556. For example, each of these corresponding phase currents multiplied by the respective winding series resistance can be equal to each of these corresponding voltage differences. In some embodiments, the gains of these phase currents can be configured based on the size of the resistors connected to the windings (e.g., based on the resistor 518 and the resistor 534, the resistor 522 and the resistor 536, or the resistor 523 and the resistor 538, respectively, and / or other resistive elements in the circuit 500).

[0057] The output terminal 504 of the circuit 500 can be connected in parallel with (i) each of the input windings 514, 516, and 517, (ii) the series path of the output windings 530, 531, and 532, (iii) the winding 546, and (iv) the RC path connected in parallel with the winding 546. In some embodiments, a load can be connected to the output terminal 504.

[0058] Figure 6 A circuit 600 including a plurality of coupled inductors connected to a TLVR and a driving MOSFET (DrMOS) circuit according to some embodiments of the present disclosure is shown. In circuit 600, elements 602, 604, 642, 644, 646, 648, 650, 652, 654, 656, 660, 662, 664, and 666 may correspond to elements 502, 504, 518, 520, 523, 525, 514, 530, 517, 532, 544, 542, 540, and 546, respectively, in some embodiments. Compared to circuit 500, circuit 600 further includes DrMOS modules 603 and 605, a control circuit module 606 (including connection pins 607-612), a first parallel RC path (including resistor 614 and capacitor 616), and a second parallel RC path (including resistor 618 and capacitor 620), wherein each parallel RC path is connected between the input and output of the respective DrMOS modules 603 and 605.

[0059] Each DrMOS module 603 and 605 includes a respective current source. The DrMOS module 603 drives a current flowing through an input winding 650 (which is coupled to an output winding 652, for example, through a shared magnetic core), while the DrMOS module 605 drives a current flowing through an input winding 654 (which is coupled to an output winding 656, for example, through a shared magnetic core). The voltage input terminal 602 may be an input terminal of each DrMOS module 603 and 605, through which an input signal may be connected to the input windings 650 and 654. Nodes 626 and 628 may be signals driven by first output terminals of the DrMOS modules 603 and 605, respectively, and provided to the control circuit module 606. Nodes 622 and 624 may be signals driven by second output terminals of the DrMOS modules 603 and 605, respectively. Nodes 622 and 626 are connected to opposite sides of a series RC path including a resistor 642 and a capacitor 644. Nodes 624 and 628 are connected to opposite sides of a series RC path including a resistor 646 and a capacitor 648. Nodes 622 and 624 are also connected to input windings 650 and 654, respectively. Node 626 is also connected to a parallel RC path including a resistor 614 and a capacitor 616, the other side of which is connected to a reference voltage (e.g., ground level or any other suitable reference voltage level) that is shared between the control circuit module 606 and the two DrMOS modules 603 and 605. For example, the reference voltage can be connected to the control circuit module 606 via pin 610. Node 628 is connected to a parallel RC path including a resistor 618 and a capacitor 620, the other side of which is also connected to a shared reference voltage. The shared reference voltage can also be connected (e.g., via pin 610) to one end of the series path including at least the output windings 650 and 654.

[0060] During operation of the circuit 600, the phase current flowing through each corresponding coupled inductor can be detected based on the voltage at nodes 626, 628, and 630. For example, the phase current flowing through the winding 650 can be indicated by the difference between the voltage at node 626 and the voltage at node 630; the phase current flowing through the winding 654 can be indicated by the difference between the voltage at node 628 and the voltage at node 630. For example, each of these corresponding phase currents multiplied by the respective winding series resistance can be equal to each of these corresponding voltage differences. In some embodiments, the gain of these phase currents can be configured based on the size of the resistors connected to the windings (e.g., based on resistors 642 and 614, and resistors 646 and 618, and / or other resistive elements in the circuit 500). Node 630 can also be connected to the control circuit module 606 (e.g., via pin 609) to achieve control of the DrMOS modules 603 and 605 based on the detected current.

[0061] The output terminal 604 of the circuit 600 can be connected in series with at least the input windings 650 and 654. In some embodiments, a load can be connected to the output terminal 604.

[0062] Circuit 600 may be expanded to three or more phases, as indicated by “■■■”, where each additional phase may include a repetition of the cumulative circuit elements and corresponding connections shown in module 670. Inclusion of such additional phases may also include additional connections to control circuit module 606 (e.g., additional repetitions of pins 611 and 612, which correspond to the positive and negative connections, respectively, from the N-phase circuit module to the control circuit).

[0063] Figure 7 A circuit 700 including a plurality of coupled inductors connected to TLVR and DrMOS circuits according to some embodiments of the present disclosure is shown. In circuit 700, components 702, 704, 706, 707, 708, 709, 710, 711, 712, 714, 716, 718, 720, 722, 724, 726, 728, 730, 742, 744, 746, 748, 750, 752, 754, 756, 760, 762, 764, and 766 may be provided in a plurality of coupled inductors. In some embodiments, they correspond to components 602, 604, 606, 607, 608, 609, 610, 611, 612, 614, 616, 618, 620, 622, 624, 626, 628, 630, 642, 644, 646, 648, 650, 652, 654, 656, 660, 662, 664 and 666. Compared with circuit 600, circuit 700 replaces DrMOS modules 603 and 605 with DrMOS modules 703 and 705, each of which includes a respective voltage source, and replaces control circuit module 606 with control circuit module 706. Circuit 700 also includes resistors 758 and 778, whose resistance values ​​determine the current provided by the voltage sources of DrMOS modules 703 and 705, respectively. In some embodiments, circuit 700 may not include resistors 714 and / or 718 .

[0064] During operation of the circuit 700 , the current flowing through each corresponding coupled inductor may be detected based on the above-mentioned steps for current detection in the circuit 600 (eg, based on the corresponding components therein).

[0065] The output terminal 704 of the circuit 700 can be connected in series with at least the input windings 750 and 754. In some embodiments, a load can be connected to the output terminal 704.

[0066] Circuit 700 may be expanded to more than three phases, as indicated by “■■■”, where each additional phase may include a duplication of the cumulative circuit elements and corresponding connections shown in module 770. Inclusion of such additional phases may also include additional connections to control circuit module 706 (e.g., additional duplications of pins 711 and 712, which correspond to positive and negative connections, respectively, from the N-phase circuit module to the control circuit).

[0067] Figure 8 A circuit 800 including a plurality of coupled inductors connected to TLVR and DrMOS circuits according to some embodiments of the present disclosure is shown. In circuit 800, components 802, 803, 804, 805, 806, 807, 808, 810, 811, 812, 814, 816, 818, 820, 822, 824, 826, 828, 830, 842, 844, 846, 848, 850, 852, 854, 856, 860, 862, 864, and 866 may be provided in a plurality of coupled inductors. In some embodiments, the reference node 809 corresponds to the elements 602, 603, 604, 605, 606, 607, 608, 610, 611, 612, 614, 616, 618, 620, 622, 624, 626, 628, 630, 642, 644, 646, 648, 650, 652, 654, 656, 660, 662, 664 and 666. Compared with the circuit 600, the circuit 800 reduces one pin in the control circuit module 806 (for example, there is no element corresponding to the pin 609). In some embodiments, removing this pin increases the flexibility of the device that can operate as the control circuit module 806. In the absence of a pin connecting the node 830 to the control circuit module 806, the reference node 809 can be connected to the pins 808 and 812.

[0068] During operation of the circuit 800 , the current flowing through each corresponding coupled inductor may be detected based on the above-mentioned steps for current detection in the circuit 600 (eg, based on the corresponding components therein).

[0069] The output terminal 804 of the circuit 800 can be connected in series with at least the input windings 850 and 854. In some embodiments, a load can be connected to the output terminal 804.

[0070] Circuit 800 may be extended to more than three phases, as indicated by “■■■”, where each additional phase may include a duplication of the cumulative circuit elements and corresponding connections shown in module 870. Inclusion of such additional phases may also include additional connections to control circuit module 806 (e.g., additional duplications of pins 811 and 812, which correspond to positive and negative connections, respectively, from the N-phase circuit module to the control circuit).

[0071] Fig. 9 A circuit 900 including a plurality of coupled inductors connected to TLVR and DrMOS circuits according to some embodiments of the present disclosure is shown. In circuit 900, components 902, 903, 904, 905, 906, 909, 908, 910, 911, 912, 914, 916, 918, 920, 922, 924, 926, 929, 930, 942, 944, 946, 948, 950, 952, 954, 956, 958, 960, 962, 964, 966, and 974 may be provided in FIG. In some embodiments, the reference node 909 corresponds to the elements 702, 703, 704, 705, 706, 707, 708, 710, 711, 712, 714, 716, 718, 720, 722, 724, 726, 727, 730, 742, 744, 746, 748, 750, 752, 754, 756, 758, 760, 762, 764, 766 and 774, respectively. Compared with the circuit 700, the circuit 900 reduces one pin in the control circuit module 906 (for example, there is no element corresponding to the pin 709). In some embodiments, removing this pin increases the flexibility of the device that can operate as the control circuit module 906. In the absence of a pin connecting the node 930 to the control circuit module 906, the reference node 909 can be connected to the pins 908 and 912.

[0072] During operation of circuit 900 , the current flowing through each corresponding coupled inductor may be detected based on the above-mentioned steps for current detection in circuit 700 (eg, based on corresponding components therein).

[0073] The output terminal 904 of the circuit 900 can be connected in series with at least the input windings 950 and 954. In some embodiments, a load can be connected to the output terminal 904.

[0074] Circuit 900 may be expanded to more than three phases, as indicated by “■■■”, where each additional phase may include a duplication of the cumulative circuit elements and corresponding connections shown in module 970. Inclusion of such additional phases may also include additional connections to control circuit module 906 (e.g., additional duplications of pins 911 and 912, which correspond to positive and negative connections, respectively, from the N-phase circuit module to the control circuit).

[0075] Thus, it is shown that a circuit has been provided for detecting current flowing through a coupled inductor.

[0076] The terms "connected to," "connected with," and variations thereof may indicate that two or more circuit elements are electrically connected to each other (e.g., via a wire, a magnetic core, a common node, or any other suitable connection). For example, the windings of a coupled inductor may be coupled via a shared magnetic core (e.g., each winding may be wound around the shared magnetic core). Devices that are connected to each other need not be directly connected to each other. For example, devices that are connected to each other may be connected directly or indirectly (e.g., via one or more intermediate elements).

[0077] The terms "input" and "output" may be used to characterize portions of a circuit. It should be understood that these characterizations are only used to illustrate some embodiments of the present disclosure. An input may function as an output, and vice versa. Either an input or an output may be connected to other circuits (including sources or loads) not shown without changing the functionality of the circuit shown or the associated teachings.

[0078] The term "phase" may be used to characterize a mode of operation of a circuit. A phase may correspond to a time sequence in which a current is driven through a winding. For a given circuit, the number of windings and / or the number of coupled inductors may correspond to the number of phases of the circuit. In some embodiments, the duty cycle of a circuit includes sequential operation through each of its phases. "Phase" may also be used to characterize a time offset, including a phase offset as related to frequency, duty cycle, or other repetitive operation. For example, each phase-based mode for operating a circuit may be associated with a respective phase offset.

[0079] The term "path" may be used to characterize a portion of a circuit, including a series of connected elements. In some embodiments, a path includes at least one conductive wire that can conduct electricity. In some embodiments, a path includes one or more devices (e.g., resistors, capacitors, windings, coupled inductors, switches, control circuits, DrMOS modules, any other suitable devices, or combinations thereof).

[0080] The term "module" may be used to characterize a portion of a circuit, including a series of connected elements. In some embodiments, a module includes a group of circuit elements that can operate in coordination with each other and are grouped together for ease of characterization.

[0081] The term "node" may be used to characterize a connected portion of a circuit (eg, a conductor) that shares a single voltage at a given moment in operation.

[0082] The term "time constant" may be used to characterize the transient response of a circuit (e.g., how quickly a circuit responds to any change in its input, output, or coupling). In some embodiments, the time constant of a given circuit path may be given by the product of resistance and capacitance (e.g., as may exist in an RC path) or by the product of inductance and the inverse of resistance (e.g., as may exist in an inductor-resistor (RL) path).

[0083] The term "switching" may be used to characterize the action of turning a switch on (e.g., creating a closed connection across the switch) and then off (e.g., creating an open connection across the switch) one or more times. Switching may be associated with a given frequency, which may correspond to the number of times a given switch is turned on per second. Switching may also be associated with a duty cycle, which may be equal to the inverse of the frequency and may correspond to the amount of time between successive operations of turning on the switch. In such operation, each time a switch is turned on, the switch may be turned off. For example, a switch may remain on for half of the duty cycle (or any other suitable amount of the duty cycle) and remain off for the remainder of the duty cycle.

[0084] The use of "■■■" in the description of a circuit may indicate that one or more repeated circuit elements (e.g., phases of a multi-phase circuit) may be included, which may not be explicit (e.g., for brevity and clarity). It should be understood that the circuit representative units shown above or below the "■■■" may be repeated and connected to the circuit shown in some embodiments of the present disclosure. These repeated circuit units may have input terminals, output terminals, and elements corresponding to the representative units of the circuit shown.

[0085] The above description of various embodiments is for the purpose of illustration and description. It is not intended to be exhaustive or limited to the exact form disclosed. In view of the above teachings, many modifications and variations are possible.

Claims

1. A current detection circuit, characterized in that: include: A coupled inductor comprising: The first winding, and Second winding; a first resistor; A first capacitor comprising: a first side connected in series with a first resistor, wherein the first resistor and the first capacitor are connected in parallel with the first winding, and a second side connected to a second capacitor; A second resistor comprising: a first side connected in series with a second resistor, wherein the second resistor and a second capacitor are connected in parallel with the second winding, and a second side connected to the first capacitor; and A third capacitor comprising: A first side connected between a first resistor and a first capacitor, and A second side connected between a second resistor and a second capacitor, wherein: A first voltage across the first capacitor indicates a first current flowing through the first winding, and A second voltage across the second capacitor is indicative of a second current flowing through the second winding.

2. The circuit according to claim 1, characterized in that A third resistor is also included which is connected in series with the third capacitor, wherein the third resistor changes the time constant of the coupled inductor.

3. The circuit according to claim 1, characterized in that Also included is at least one third resistor connected in parallel with at least one of the first capacitor, the second capacitor or the third capacitor, wherein the at least one third resistor scales at least one of the first or second voltage.

4. The circuit according to claim 1, characterized in that A plurality of switches are also included to control current flowing through the first and second windings.

5. The circuit according to claim 4, characterized in that The plurality of switches include first and second switches connected in series and third and fourth switches connected in series, The first winding is connected between the first and second switches, and The second winding is connected between the third and fourth switches.

6. The circuit according to claim 1, characterized in that The output ends of the first and second windings are connected, and the circuit further comprises: A tertiary winding, where: A first side of the third winding is connected in series with the connected output terminals of the first and second windings, and The second side of the third winding is connected between the first and second capacitors.

7. The circuit according to claim 1, characterized in that The output terminals of the first and second windings are connected, and the circuit further comprises: N-2 windings, of which: N corresponds to the number of phases of the coupled inductors, and Each of the N-2 windings corresponds to a respective phase and has an output terminal connected to the connected output terminals of the first and second windings; N-2 phase resistors, each phase resistor corresponding to a respective phase; N-2 phase capacitors, each phase capacitor corresponds to a respective phase and includes: The first side is connected in series with each of the N-2 phase resistors, wherein the N-2 phase Each set of one of the resistors and one of the N-2 phase capacitors is connected in parallel with a corresponding one of the N-2 windings; and A second side connected to the connected output terminals of the first and second windings; and (N-1)!-1 coupling capacitors, each of the (N-1)!-1 coupling capacitors includes: A first side is connected between the respective first phase resistors and the respective first phase capacitors, and a second side is connected between the respective second phase resistors and the respective second phase capacitors.

8. A current detection circuit, characterized in that: include: A coupled inductor consists of N windings, where: N corresponds to the number of phases of the coupled inductors, and The N windings have connected output terminals; N first resistors; N first capacitors, each of which includes: a first side connected in series with a respective first resistor, wherein the respective first resistor and the respective first capacitor are connected in parallel with one of the N windings, and A second side connected to the output terminals connected to the N windings; N first amplifiers, wherein: The first input terminal of each first amplifier is connected between a respective first resistor and a respective first capacitor, A second input terminal of each first amplifier is connected to the connected output terminals of the N windings; and A second amplifier and N second resistors, where: A first input terminal of the second amplifier is connected to the connected output terminals of the N windings, and The second input of the second amplifier is connected to a common node, where: Each input terminal of each corresponding winding is connected in series with a corresponding one of the N second resistors, each of the N second resistors is further connected to a common node, and A respective sum of an output voltage of each of the N first amplifiers and an output voltage of the second amplifier indicates a current flowing through a respective one of the N windings.

9. The circuit according to claim 8, characterized in that Also included are N third resistors, wherein: each of the N third resistors is connected in parallel with a corresponding one of the N first capacitors, Each of the N third resistors scales the voltage of the first input terminal of each first amplifier.

10. The circuit according to claim 8, characterized in that A plurality of switches are also included to control the current flowing through the N windings.

11. The circuit according to claim 10, characterized in that The plurality of switches include N pairs of first and second switches, wherein each pair of first and second switches is connected in series, and Each winding is connected between a corresponding pair of first and second switches.

12. The circuit according to claim 8, characterized in that Also included is a third capacitor comprising: A first side connected to a common node, and A second side connected to the connected output terminals of the N windings.

13. A current detection circuit, characterized in that: include: a first coupled inductor including a first input winding and a first output winding; a second coupled inductor comprising a second input winding and a second output winding, wherein the first output winding is connected in series with the second output winding; first and second resistors; The first capacitor includes: a first side connected in series with the first resistor and in parallel with the second resistor, and a second side connected in series with the first input winding; third and fourth resistors; The second capacitor comprises: a first side connected in series with a third resistor and in parallel with a fourth resistor, and a second side connected in series with a second input winding; a third inductor connected in series with the first and second output windings; fifth and sixth resistors connected in series; and The third capacitor includes: connected between the fifth and sixth resistors on the first side, and connected to the second side between the second output winding and the third inductor, wherein: A difference between a first voltage across the first capacitor and a detected voltage across the third capacitor indicates a first current flowing through the first coupled inductor, and A difference between a second voltage across the second capacitor and a detected voltage across the third capacitor indicates a second current flowing through the second coupled inductor.

14. The circuit according to claim 13, characterized in that A plurality of switches are also included to control current flowing through the first and second windings.

15. The circuit according to claim 14, characterized in that The plurality of switches include first and second switches connected in series, and third and fourth switches connected in series, The first input winding is connected between the first and second switches, and The second input winding is connected between the third and fourth switches.

16. The circuit according to claim 13, characterized in that Also includes: N-2 coupled inductors, each coupled inductor includes a respective input winding and a respective output winding, wherein: N corresponds to the number of phases of the coupled inductors, and The respective output windings of N-2 coupled inductors are connected in series; 2N-4 resistors, wherein each of the N-2 coupled inductors is connected to corresponding two of the 2N-4 resistors; N-2 capacitors, wherein each of the N-2 coupled inductors is connected to a corresponding one of the N-2 capacitors, and each of the N-2 capacitors includes: a first side connected in series with a first resistor of corresponding two of the 2N-4 resistors and connected in parallel with a second resistor of corresponding two of the 2N-4 resistors, and A second side connected in series with a corresponding input winding of one of the N-2 coupled inductors, wherein: a current flowing through each of the N-2 coupled inductors is indicated by a difference between a voltage across a corresponding one of the N-2 capacitors and a detection voltage.

17. A current detection circuit, characterized in that: include: a first coupled inductor including a first input winding and a first output winding; a second coupled inductor comprising a second input winding and a second output winding, wherein the first output winding is connected in series with the second output winding; First and second DrMOS modules to control currents flowing through the first and second coupled inductors, wherein first output terminals of the first and second DrMOS modules are connected in series with the first and second input windings, respectively; The first capacitor includes: a first side connected in series with the second output terminal of the first DrMOS module, and a second side connected to a first reference voltage; The second capacitor comprises: a first side connected in series with a second output terminal of a second DrMOS module, and a second side connected to a second reference voltage; a first and a second resistor connected in parallel with the first and the second capacitor, respectively; a third inductor connected in series with the first and second output windings; A third resistor and a third capacitor are connected in series between the first and second output terminals of the first DrMOS module; a fourth resistor and a fourth capacitor connected in series between the first and second output terminals of the second DrMOS module; and The fifth capacitor includes: a first side connected in series with a fifth resistor and in parallel with a sixth resistor, and connected to the second side between the second output winding and the third inductor, wherein: A difference between a voltage across the first capacitor and a voltage across the fifth capacitor indicates a first current flowing through the first coupled inductor, and A difference between a voltage across the second capacitor and a voltage across the fifth capacitor indicates a second current flowing through the second coupled inductor.

18. The circuit according to claim 17, characterized in that Also includes: A control circuit for controlling the first and second DrMOS modules, wherein: The first and second output terminals of the control circuit are connected to the first side and the second side of the first capacitor respectively, and The third and fourth output terminals of the control circuit are connected to the first side and the second side of the second capacitor respectively.

19. The circuit according to claim 17, characterized in that Also includes: a fifth resistor connected in parallel with the first capacitor, wherein the fifth resistor scales the first voltage across the first capacitor; as well as A sixth resistor is connected in parallel with the second capacitor, wherein the sixth resistor scales a second voltage across the second capacitor.

20. The circuit according to claim 17, characterized in that Also includes: N-2 coupled inductors, where: N corresponds to the number of phases of the coupled inductor, Each coupled inductor includes an input winding and an output winding, and The output windings of N-2 coupled inductors are connected in series with the first and second output windings; N-2 DrMOS modules, each of the N-2 DrMOS modules corresponding to a respective phase and configured to control a current flowing through one of the N-2 coupled inductors; and 2N-4 resistors and 2N-4 capacitors, where: Each group of two resistors in the 2N-4 resistors and two capacitors in the 2N-4 capacitors corresponds to a respective phase; A first one of two resistors among the 2N-4 resistors and a first one of two capacitors among the 2N-4 capacitors are connected in parallel with a first output terminal of a corresponding DrMOS module and a corresponding reference voltage; The second of the two resistors among the 2N-4 resistors and the second of the two capacitors among the 2N-4 capacitors are connected in series with the first and second output terminals of the corresponding DrMOS module, wherein: The difference between the voltage across the first of the two capacitors and the voltage across the fifth capacitor is indicative of the current flowing through the corresponding coupled inductor.

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