Power conversion circuit with limited power source function and control method thereof

Abstract

A power conversion circuit with a limited power source function and a control method thereof. The power conversion circuit, for generating a supply voltage according to an input voltage, includes a path switch for controlling a conduction path of the supply voltage to a bus power voltage, a first current sensing circuit for generating a current sensing voltage according to a current supplied to a load, a second current sensing circuit including the path switch or a conductor connection line segment for generating a judgment voltage according to the current, and a power control circuit for executing a limited power source control procedure according to the current sensing voltage and the judgment voltage. The limited power source control procedure includes a judgment step for judging whether the current sensing voltage is lower than a sensing threshold and whether an absolute value of the judgment voltage is higher than an absolute value of a judgment threshold, and a limited power source operation for limiting an output power related to the current. When a judgment result of the judgment step is yes, the limited power source operation is performed.

Description

Technical Field

[0001] This invention relates to a power conversion circuit, and more particularly to a power conversion circuit with a power limiting source function. The invention also relates to a control method for controlling the aforementioned power conversion circuit. Background Technology

[0002] In power applications such as USB Power Delivery (USB PD), to comply with the Limit Power Source (LPS) specification, the system must still prevent excessive output power from causing overload when a single component fails (such as a current sensing resistor fails). Existing technologies mostly rely on sophisticated power calculation circuits combined with firmware algorithms or CC pin communication combined with current detection to determine whether LPS has been entered. While this can achieve the protection purpose, common problems include: circuit complexity, increased component costs, heavy firmware burden, and susceptibility to false alarms during startup or transition, requiring additional logic and timing to suppress false alarms. Summary of the Invention

[0003] From one perspective, the present invention provides a power conversion circuit for generating a supply voltage based on an input voltage, comprising: a path control switch coupled between the supply voltage and a bus power supply voltage for controlling a conduction path from the supply voltage to the bus power supply voltage, wherein the bus power supply voltage is used to provide a current to a load; a first current sensing circuit including a sensing resistor connected in series in a current path of the current for generating a current sensing voltage based on the current; and a second current sensing circuit including the path control switch connected in series in the current path. A switch or a conductor connecting line segment for generating a judgment voltage based on the current; and a power control circuit for controlling the path control switch and for executing a power limiting source control program based on the current sensing voltage and the judgment voltage; wherein the power limiting source control program includes: a first judgment step: determining whether the current sensing voltage is lower than a sensing threshold and whether an absolute value of the judgment voltage is higher than an absolute value of a judgment threshold; and a power limiting source operation: limiting an output power related to the current; wherein the power limiting source operation is performed when the judgment result of the first judgment step is yes.

[0004] In one embodiment, the power control circuit is configured as an integrated circuit; a first terminal and a second terminal of the first current sensing circuit are coupled to a first pair of pins of the power control circuit, the first pair of pins corresponding to a sensing pin and a ground pin of the power control circuit; a first terminal and a second terminal of the second current sensing circuit are coupled to a second pair of pins of the power control circuit. The power control circuit is configured as follows: First configuration: When the second current sensing circuit generates the judgment voltage through the path control switch, the second pair of pins corresponds to a power supply pin and a bus pin of the power control circuit, wherein a first end of the path control switch is coupled to the power supply pin, a second end of the path control switch is coupled to the bus pin, and a control end of the path control switch is coupled to a control pin of the power control circuit, wherein the judgment voltage corresponds to a conduction voltage when the path control switch is turned on; or Second configuration: When the second current sensing circuit generates the judgment voltage through the conductor connecting segment, the second pair of pins corresponds to the ground pin and a first pin of the power control circuit, wherein a first end of the conductor connecting segment is coupled to the ground pin, and a second end of the conductor connecting segment is coupled to the first pin, wherein the judgment voltage corresponds to a voltage across the first end and the second end of the conductor connecting segment.

[0005] In one embodiment, the power control circuit includes: a first amplifier circuit coupled to the first pair of pins for amplifying the current sensing voltage to generate a first amplified signal; an analog-to-digital converter circuit for converting the first amplified signal to generate a first digital amplified signal in the digital domain; and a determination circuit for executing the power limiting source control program based on the first digital amplified signal and the determination voltage.

[0006] In one embodiment, when the power control circuit is configured in the first configuration, the analog-to-digital conversion circuit is further configured to convert the on-state voltage to generate a second digital amplified signal in the digital domain, and the determination circuit is further configured to execute the power limiting source control program based on the first digital amplified signal and the second digital amplified signal; or the power control circuit further includes a comparator for comparing the on-state voltage with the determination threshold to generate a comparison signal, and the determination circuit is further configured to execute the power limiting source control program based on the first digital amplified signal and the comparison signal.

[0007] In one embodiment, the power limiting source control program further includes a first delay operation: waiting for a first delay time; when the judgment result of the first judgment step is yes, the first delay operation is performed again, and then the power limiting source operation is performed.

[0008] In one embodiment, the power limiting source control program further includes a second judgment step: determining whether the path control switch is turned on; and a second delay operation: waiting for a second delay time; when the judgment result of the second judgment step is yes, the second delay operation is performed, and then the first judgment step is performed.

[0009] In one embodiment, the power limiting source operation includes: turning off the path control switch or increasing a conduction resistance value of the path control switch.

[0010] In one embodiment, the current sensing threshold corresponding to the sensing threshold is lower than the absolute value of the current judgment threshold corresponding to the judgment threshold.

[0011] In one embodiment, when the power control circuit is configured in the second configuration, the power control circuit further includes a second amplification circuit for amplifying the voltage across the conductor connecting segment through the second pair of pins to generate a second amplified signal; the analog-to-digital conversion circuit is further configured to convert the second amplified signal to generate a third digital amplified signal in the digital domain; and the determination circuit is further configured to execute the power limiting source control program based on the first digital amplified signal and the third digital amplified signal.

[0012] In one embodiment, the second end of the conductor connecting segment is further coupled to the first pin via a temperature sensing resistor. The power control circuit further includes a current source circuit for providing a bias current. During a first time period, the second amplification circuit receives the voltage across the conductor connecting segment through the first pin, and the determination circuit executes the power limiting source control program based on the first digital amplification signal and the third digital amplification signal. During a second time period, the current source circuit provides the bias current to the temperature sensing resistor through the first pin, thereby generating a voltage across the temperature sensing resistor. During the second time period, the analog-to-digital conversion circuit is further used to convert the voltage across the temperature sensing resistor to generate a digital temperature sensing signal in the digital domain. During the second time period, the determination circuit is further used to determine whether the temperature of the temperature sensing resistor is higher than an over-temperature protection threshold based on the digital temperature sensing signal.

[0013] From another perspective, the present invention also provides a control method for controlling a power conversion circuit to generate a supply voltage based on an input voltage, comprising: controlling a conduction path of the supply voltage to a bus power supply voltage via a path control switch, wherein the bus power supply voltage is used to provide a current to a load; generating a current sensing voltage in a first current sensing circuit based on the current, wherein the first current sensing circuit includes a sensing resistor connected in series in a current path of the current; generating a judgment voltage in a second current sensing circuit based on the current, wherein the second current sensing circuit includes the path control switch or a conductor connecting segment connected in series in the current path; and executing a power limiting source control program based on the current sensing voltage and the judgment voltage; wherein the power limiting source control program includes: a first judgment step: determining whether the current sensing voltage is lower than a sensing threshold and whether an absolute value of the judgment voltage is higher than an absolute value of a judgment threshold; and a power limiting source operation: limiting an output power related to the current; wherein the power limiting source operation is performed when the judgment result of the first judgment step is yes.

[0014] The power conversion circuit of this invention utilizes both current-sensing voltage and judgment voltage for dual judgment to execute a power source limiting control program, preventing continuous current rise and load damage caused by abnormal sensing resistor. When the current-sensing voltage is lower than the sensing threshold and the absolute value of the judgment voltage is higher than the absolute value of the judgment threshold, the circuit performs power source limiting operation to limit the output power related to the output current, preventing abnormal current rise from damaging the load. This control mechanism can generate the judgment voltage from the conduction voltage of the path control switch or the voltage across the conductor connection segment, and can be further combined with delayed judgment and temperature sensing control to achieve accurate and reliable power source limiting protection.

[0015] The following detailed description through specific embodiments will make it easier to understand the purpose, technical content, features and effects achieved by the present invention. Attached Figure Description

[0016] Figure 1A and Figure 1B Block diagrams of the power conversion circuits in two embodiments of the present invention are shown respectively.

[0017] Figure 2A This diagram shows the operation flowchart of the power source limiting control program of the power conversion circuit in one embodiment of the present invention.

[0018] Figure 2B This diagram shows the operation flowchart of the power source control program for the power conversion circuit in another embodiment of the present invention.

[0019] Figure 3A This diagram shows a power conversion circuit according to one embodiment of the present invention.

[0020] Figure 3B This diagram shows a power conversion circuit according to one embodiment of the present invention.

[0021] Figure 4A This diagram shows a power control circuit of a power conversion circuit according to an embodiment of the present invention.

[0022] Figure 4B This diagram shows a power control circuit of a power conversion circuit according to an embodiment of the present invention.

[0023] Figure 5 This illustrates an embodiment of the present invention corresponding to... Figure 3A The operating waveform diagram of the power conversion circuit.

[0024] Figure 6A This diagram shows a power conversion circuit according to one embodiment of the present invention.

[0025] Figure 6B This diagram shows a power conversion circuit according to one embodiment of the present invention.

[0026] Figure 7 This diagram shows a power control circuit of a power conversion circuit according to an embodiment of the present invention.

[0027] Figure 8 This illustrates an embodiment of the present invention corresponding to... Figure 6A The operating waveform diagram of the power conversion circuit.

[0028] Figure 9A This diagram shows a power conversion circuit according to one embodiment of the present invention.

[0029] Figure 9B This diagram shows a power conversion circuit according to one embodiment of the present invention.

[0030] Figure 10A and Figure 10B This diagram shows a power control circuit of a power conversion circuit in one embodiment of the present invention at different time periods.

[0031] Figure 11A This illustrates an embodiment of the present invention corresponding to... Figure 9A The operating waveform diagram of the power conversion circuit.

[0032] Figure 11B Another embodiment of the present invention corresponds to Figure 9A The operating waveform diagram of the power conversion circuit.

[0033] Figure 12 This diagram shows the operation flowchart of the power source limiting control program of the power conversion circuit in one embodiment of the present invention.

[0034] Explanation of symbols in the diagram

[0035] 90: Load

[0036] 100: First current sensing circuit

[0037] 200: Second current sensing circuit

[0038] 300, 3004A, 3004B, 3007, 3010: Power control circuit

[0039] 310: First amplifier circuit

[0040] 320: Analog-to-digital converter circuit

[0041] 330: Judgment Circuit

[0042] 340: Comparator

[0043] 350: Second amplifier circuit

[0044] 360: Current source circuit

[0045] 500: Power stage circuit

[0046] 600: Primary side control circuit

[0047] 700: Rectifier switch control circuit

[0048] 1001A, 1001B, 1003A, 1003B: Power conversion circuit

[0049] 1006A, 1006B, 1009A, 1009B: Power conversion circuits

[0050] Iout: Output current

[0051] Ipth: Current path

[0052] Ithcs: Current sensing threshold

[0053] Ithx: Current Judgment Threshold

[0054] Lc: Connecting unit

[0055] Lgnd: Load grounding potential

[0056] OC: Optical coupling element

[0057] OPTO: Coupling pin

[0058] P1: First pin

[0059] P100: Power Limiting Source Control Program

[0060] PBUS: Bus pin

[0061] PCC1: Channel pin

[0062] PCC2: Channel pin

[0063] PCS: Sensing pin

[0064] PGND: Ground pin

[0065] PLPS: Power Limiting Source Pin

[0066] PM: Multiplexing pin

[0067] PUSB: Control pin

[0068] PVDD: Power supply pin

[0069] Q1: Primary side switch

[0070] Q2: Rectifier switch

[0071] QB: Path control switch

[0072] Rco: Connection wire resistance

[0073] Rcs: Sensing resistor

[0074] RT: Temperature sensing resistor

[0075] S1: First signal path switch

[0076] S2: Second signal path switch

[0077] S10: Start Operation Steps

[0078] S101: First Judgment Step

[0079] S102: Power-limited source operation

[0080] S103: First Delay Operation

[0081] S201: Second Judgment Step

[0082] S202: Second Delay Operation

[0083] Scp: Comparison signal

[0084] SD: Digital output signal

[0085] Sgnd: Ground potential of power control circuit

[0086] t1, t2, t3: Time points

[0087] Tp1: First period

[0088] Tp2: Second period

[0089] TR: Transformer

[0090] Va1: First amplified signal

[0091] Va2: Second amplified signal

[0092] Vbus: Bus power supply voltage

[0093] Vco: Voltage across the conductor connection segment

[0094] Vcoth: Transpressure threshold

[0095] Vcs: Current sensing voltage

[0096] Vcsth: Sensing threshold

[0097] Vdd: Supply voltage

[0098] Vds: Turn-on voltage

[0099] Vdsth: Turn-on voltage threshold

[0100] Vfb: Feedback signal

[0101] Vin: Input voltage

[0102] Vlps: Power Limiting Source Indication Signal

[0103] Vocpth: Overcurrent threshold voltage

[0104] VoTP: Over-temperature indication signal

[0105] Vrt: Temperature sensing voltage

[0106] Vtth: Temperature threshold

[0107] Vx: Determines voltage

[0108] Vxth: Threshold determination

[0109] VBUS: USB power pin

[0110] W1: Primary winding

[0111] W2: Secondary winding

[0112] Vtrl: Control signal Detailed Implementation

[0113] The accompanying drawings in this invention are schematic and are primarily intended to illustrate the coupling relationships between circuits and the relationships between signal waveforms. The circuits, signal waveforms, and frequencies are not drawn to scale. For clarity, many practical details will be described in the following description, but this is not intended to limit the broadest scope of this invention.

[0114] Figure 1A and Figure 1B Block diagrams of the power conversion circuits in two embodiments of the present invention are shown respectively. For example... Figure 1A As shown, in one embodiment, the power conversion circuit 1001A includes: a path control switch QB, a first current sensing circuit 100, a second current sensing circuit 200, a power control circuit 300, and a power stage circuit 500. In one embodiment, the power conversion circuit 1001A is used to generate a supply voltage Vdd based on the input voltage Vin. Specifically, the power conversion circuit 1001A converts the input voltage Vin into the supply voltage Vdd through the power stage circuit 500. In one embodiment, the power stage circuit 500 is, for example, a switching converter.

[0115] In one embodiment, a path control switch QB is coupled between a supply voltage Vdd and a bus power supply voltage Vbus to control the conduction path from the supply voltage Vdd to the bus power supply voltage Vbus. In one embodiment, the bus power supply voltage Vbus provides current Iout to the load 90. In one embodiment, a first current sensing circuit 100 includes a sensing resistor Rcs, connected in series with the current path Ipth of current Iout, to generate a current sensing voltage Vcs based on current Iout. Specifically, one end of the sensing resistor Rcs is coupled to ground potential Lgnd along with the load 90 and the power control circuit 300, and the other end of the sensing resistor Rcs is coupled to ground potential Sgnd along with the power control circuit 300. In one embodiment, the power control circuit 300 controls the path control switch QB and executes a power-limited source control program based on the current sensing voltage Vcs and the judgment voltage Vx.

[0116] like Figure 1B As shown, in one embodiment, the power conversion circuit 1001B is used to generate a supply voltage Vdd based on the input voltage Vin. Figure 1B In the power conversion circuit 1001B, the configuration and operation of the path control switch QB, the first current sensing circuit 100, the power control circuit 300, and the power stage circuit 500 are related to... Figure 1A Same as above, please refer to the foregoing explanation. Figure 1A The power conversion circuit 1001A and Figure 1B The difference between the power conversion circuit 1001B and the second current sensing circuit 200 lies in the configuration and operation of the second current sensing circuit, which will be described in detail later.

[0117] In one embodiment, such as Figure 1A As shown, the second current sensing circuit 200 includes a path control switch QB series coupled to the current path Ipth. In another embodiment, as... Figure 1B As shown, the second current sensing circuit 200 includes a conductor connection segment connected in series with the current path Ipth, such as... Figure 1B As shown by the gray lines, this could be, for example, a section of copper foil conductor on a printed circuit board. In this embodiment, the conductor connection segment has a connection resistance value Rco greater than 0. In one embodiment, Figure 1A and Figure 1B The second current sensing circuit 200 is used to generate a judgment voltage Vx based on the current Iout.

[0118] Figure 2A This diagram shows an operation flowchart of a power source limiting control program for a power conversion circuit according to an embodiment of the present invention. In one embodiment, after the power conversion circuit starts operating in step S10, it enters the power source limiting control program P100. In one embodiment, the power source limiting control program P100 includes a first judgment step S101 and a power source limiting operation S102. In one embodiment, the first judgment step S101 includes: judging whether the current sensing voltage Vcs is lower than the sensing threshold Vcsth and judging whether the absolute value of the voltage Vx is higher than the absolute value of the judgment threshold Vxth. The power source limiting operation S102 includes: limiting the output power related to the current Iout. In one embodiment, when the judgment result of the first judgment step S101 is yes, that is, when the current sensing voltage Vcs is lower than the sensing threshold Vcsth and the absolute value of the voltage Vx is higher than the absolute value of the judgment threshold Vxth, the power source limiting operation S102 is performed. In another embodiment, when the judgment result of the first judgment step S101 is negative, the first judgment step S101 is repeated until the judgment result of the first judgment step S101 is positive, and then the power limiting source operation S102 is started.

[0119] In one embodiment, the sensing threshold Vcsth corresponds to the current sensing threshold Ithcs, and the absolute value of the judgment threshold Vxth corresponds to the absolute value of the current judgment threshold Ithx. In one embodiment, when the current sensing voltage Vcs is lower than the sensing threshold Vcsth, it indicates that the current Iout is lower than the current sensing threshold Ithcs; when the absolute value of the judgment voltage Vx is higher than the absolute value of the judgment threshold Vxth, it indicates that the current Iout is higher than the current judgment threshold Ithx. In one embodiment, the current sensing threshold Ithcs is lower than the absolute value of the current judgment threshold Ithx.

[0120] Figure 2B This diagram shows the operation flowchart of the power source limiting control program for the power conversion circuit in another embodiment of the present invention. In one embodiment, as... Figure 2B As shown, the power source limiting control program P100 further includes a first delay operation S103. In one embodiment, the first delay operation S103 includes waiting for a first delay time Td1. In one embodiment, when the judgment result of the first judgment step S101 is yes, the first delay operation S103 is also performed. In this embodiment, the power source limiting operation S102 is performed after the first delay operation S103. The first delay time Td1 can reduce noise interference and improve the de-jitter effect. Figure 2B For other undescribed steps, please refer to Figure 2A Explanation.

[0121] Figure 3A This diagram shows a power conversion circuit according to one embodiment of the present invention. Figure 3A The power conversion circuit 1003A is corresponding to Figure 1A One embodiment of the power conversion circuit 1001A. In one embodiment, in the power conversion circuit 1003A, the power control circuit 300 is configured as an integrated circuit (the same applies to the following embodiments). In a specific embodiment, the power control circuit 300 includes a power supply pin PVDD, a bus pin PBUS, a ground pin PGND, a sensing pin PCS, a control pin PUSB, and channel pins PCC1 and PCC2, which are respectively coupled to the corresponding pins of the load 90 via connection units Lc in a removable manner, for example, wherein the connection unit Lc corresponds, for example, to a connector and / or connection cable of a USB Type-C interface. In one embodiment, the power supply pin PVDD is used to receive the supply voltage Vdd from the power stage circuit 500 and provide power to drive the internal circuitry of the power control circuit 300. The bus pin PBUS is used to detect the bus power supply voltage Vbus. The ground pin PGND is used to provide the ground potential Sgnd of the power control circuit 300. The sensing pin PCS is coupled to the aforementioned ground potential Lgnd and is used to receive the current sensing voltage Vcs generated by the sensing resistor Rcs, thereby sensing the current Iout flowing through the load 90. The control pin PUSB is used to transmit the control signal Vtrl to control the path control switch QB. The channel pins PCC1 and PCC2 correspond, for example, to the configuration channel pins CC1 and CC2 of the USB Type-C interface, and are used for insertion direction determination and communication connection establishment.

[0122] like Figure 3AAs shown, in one embodiment, the first and second terminals of the first current sensing circuit 100 (sensing resistor Rcs) are coupled to a first pair of pins of the power control circuit 300. In this embodiment, the first pair of pins corresponds to the sensing pin PCS and the ground pin PGND of the power control circuit 300. In one embodiment, the second current sensing circuit 200 corresponds to the path control switch QB, and the first and second terminals of the second current sensing circuit 200 (i.e., the path control switch QB) are coupled to a second pair of pins of the power control circuit 300. Figure 3A In one embodiment, the power control circuit 300 is configured in a first configuration: when the second current sensing circuit 200 generates a judgment voltage Vx through the path control switch QB, the second pair of pins corresponds to the power supply pin PVDD and the bus pin PBUS of the power control circuit 300.

[0123] In one specific embodiment, the path control switch QB is configured as an N-type metal-oxide-semiconductor (MOS) transistor (the path control switch in the following embodiments is the same). Figure 3A In this embodiment, the first terminal (drain) of the path control switch QB is coupled to the power supply pin PVDD, the second terminal (source) of the path control switch QB is coupled to the bus pin PBUS, and the control terminal (gate) of the path control switch QB is coupled to the control pin PUSB of the power control circuit 300. In this embodiment, the judgment voltage Vx corresponds to the on-state voltage of the path control switch QB when it is turned on (i.e., the drain-source voltage of the path control switch QB when it is turned on). It should be noted that the path control switch QB has a conduction resistance value greater than 0 when it is turned on. In this embodiment, the on-state voltage Vds of the path control switch QB when it is turned on corresponds to the product of the current Iout and the conduction resistance value of the path control switch QB.

[0124] Please also refer to Figure 2A , Figure 2B and Figure 3A In one embodiment, the power limiting source operation S102 includes: turning off the path control switch QB or increasing the on-resistance value of the path control switch QB (i.e., reducing the on- or driving capability of the path control switch QB). Specifically, in this embodiment, by reducing the voltage of the control signal Vtrl, the gate voltage of the path control switch QB (NMOS transistor) decreases, thereby turning off the path control switch QB or increasing the on-resistance value of the path control switch QB, thereby achieving the purpose of limiting the power source.

[0125] Figure 3B This diagram shows a power conversion circuit according to one embodiment of the present invention. Figure 3B The power conversion circuit 1003B is corresponding to Figure 3AA specific embodiment of the power conversion circuit 1003A. For example... Figure 3B As shown, in one embodiment, the power conversion circuit 1003B is configured as a flyback power conversion circuit. In one embodiment, the power stage circuit 500 includes a transformer TR, a primary-side switch Q1, a primary-side control circuit 600, and a rectifier switch Q2. In one embodiment, the transformer TR includes a primary-side winding W1 and a secondary-side winding W2. The primary-side winding W1 is coupled to the input voltage Vin, and the secondary-side winding W2 is coupled to the supply voltage Vdd. The primary-side control circuit 600 controls the primary-side switch Q1 coupled to the primary-side winding W1 according to the feedback signal Vfb, thereby switching the primary-side winding W1 to switch the input voltage Vin, so that the secondary-side winding W2 generates the supply voltage Vdd. In one embodiment, the rectifier switch Q2 is connected in series with the current path Ipth of the current Iout. Specifically, in this embodiment, the rectifier switch Q2 is coupled between the sensing resistor Rcs and the secondary-side winding W2. The rectifier switch control circuit 700 controls the rectifier switch Q2 to perform synchronous rectification on the secondary side. In one embodiment, the power supply control circuit 300 further includes a coupling pin OPTO for generating a feedback signal Vfb to the primary side control circuit 600 via an optocoupler OC based on feedback from the supply voltage Vdd. Figure 3B For other details not specified, please refer to Figure 3A Explanation.

[0126] Figure 4A This diagram shows a power control circuit of a power conversion circuit according to an embodiment of the present invention. Figure 4A The power control circuit 3004A is corresponding to Figure 3A A specific embodiment of the power control circuit 300. For example... Figure 4AAs shown, in one embodiment, the power control circuit 3004A includes a first amplifier circuit 310, an analog-to-digital converter circuit 320, and a decision circuit 330. In one embodiment, the first amplifier circuit 310 is coupled to a first pair of pins (i.e., the sensing pin PCS and the ground pin PGND) to amplify the current sensing voltage Vcs to generate a first amplified signal Va1. The analog-to-digital converter circuit 320 converts the first amplified signal Va1 to generate a first digital amplified signal in the digital domain. In one embodiment, the analog-to-digital converter circuit 320 is also coupled to a second pair of pins (corresponding here to the power supply pin PVDD and the bus pin PBUS) to convert the decision voltage Vx (corresponding here to the on-state voltage Vds) to generate a second digital amplified signal in the digital domain. In one embodiment, the analog-to-digital converter circuit 320 generates a digital output signal SD based on the first and second digital amplified signals. The determination circuit 330 executes the power-limiting source control program P100 based on the digital output signal SD (i.e., including the first digital amplified signal and the second digital amplified signal). In other words, the determination circuit 330 executes the power-limiting source control program P100 based on the first digital amplified signal and the determination voltage Vx (conduction voltage Vds). In a specific embodiment, the determination circuit 330 corresponds, for example, to a microcontroller unit. In this embodiment, the determination comparison in the aforementioned first determination step S101 can be performed by the determination circuit 330 in the digital domain.

[0127] It should be noted that, in one embodiment, the analog-to-digital converter 320 converts the first amplified signal Va1 to generate a first digital amplified signal and converts the on-state voltage Vds to generate a second digital amplified signal during the first and second conversion periods, respectively, and then generates a digital output signal SD based on the first digital amplified signal or the second digital amplified signal. In one embodiment, the digital output signal SD generated by the analog-to-digital converter 320 corresponds to the first digital amplified signal during the first conversion period and to the second digital amplified signal during the second conversion period; in other words, the analog-to-digital converter 320 shares the above-mentioned analog-to-digital conversion in a time-sharing manner. In other embodiments, the analog-to-digital converter 320 may also include multiple sub-analog-to-digital converters, simultaneously performing analog-to-digital conversion between the first amplified signal Va1 and the on-state voltage Vds to simultaneously generate multiple sub-digital output signals corresponding to the digital output signal SD.

[0128] Figure 4B This diagram shows a power control circuit of a power conversion circuit according to an embodiment of the present invention. Figure 4B The power control circuit 3004B is corresponding to Figure 3A Another specific embodiment of the power control circuit 300. Figure 4B The power control circuit 3004B is similar to Figure 4A The power control circuit of the 3004A is described below, highlighting the differences. For example... Figure 4B As shown, in one embodiment, the power control circuit 3004B further includes a comparator 340 for comparing the on-state voltage Vds with a judgment threshold Vxth to generate a comparison signal Scp. The judgment circuit 330 is also used to execute a power limiting source control program P100 based on the first digital amplified signal and the comparison signal Scp. It should be noted that in... Figure 4B In one embodiment, the digital output signal SD generated by the analog-to-digital converter 320 corresponds to the first digital amplified signal.

[0129] Please also refer to Figure 2B , Figure 3A and Figure 5 . Figure 5 This illustrates an embodiment of the present invention corresponding to... Figure 3A The operating waveform diagram of the power conversion circuit. In this embodiment, corresponding to... Figure 3A In one embodiment, the voltage Vx is determined to correspond to the on-state voltage Vds when the path control switch QB is turned on, and the threshold Vxth corresponds to the on-state voltage threshold Vdsth. For example... Figure 5 As shown, the current Iout gradually increases over time. At time t1, the current sensing voltage Vcs is lower than the sensing threshold Vcsth, and the absolute value of the judgment voltage Vx is higher than the absolute value of the judgment threshold Vxth. In this embodiment, the judgment result of the first judgment step S101 at time t1 is yes, at which point the first delay operation S103 is performed, that is, waiting for the first delay time Td1. Then at time t2, the power limiting source indication signal Vlps turns to a high level, indicating that the power limiting source operation S102 is performed.

[0130] It should be noted that, in one embodiment, as Figure 5 As shown, the current Iout gradually increases over time, and the judgment voltage Vx also increases with the current Iout. However, the current sensing voltage Vcs does not gradually increase with the current Iout, but remains below the sensing threshold Vcsth. These two conflicting pieces of information indicate that the sensing resistor Rcs may have malfunctioned and cannot sense the current according to the normal operating procedure. This invention, through the first judgment step S101 of the power limiting source control program P100, performs a power limiting operation S102 when the current sensing voltage Vcs is lower than the sensing threshold Vcsth and the absolute value of the judgment voltage Vx is higher than the absolute value of the judgment threshold Vxth, or waits for a first delay time Td1 before performing the power limiting operation S102. This limits the output power related to the current Iout to achieve the purpose of power limiting, preventing the current Iout from continuously rising due to the abnormality of the sensing resistor Rcs, which could damage the load 90.

[0131] Figure 6AThis diagram shows a power conversion circuit according to one embodiment of the present invention. Figure 6A The power conversion circuit 1006A is corresponding to Figure 1B An embodiment of the power conversion circuit 1001B. In a specific embodiment, the power control circuit 300 of the power conversion circuit 1006A includes a first pin P1, a ground pin PGND, a sensing pin PCS, a control pin PUSB, and channel pins PCC1 and PCC2, wherein the sensing pin PCS, channel pins PCC1 and PCC2 are respectively coupled to the load 90 via the connection unit Lc.

[0132] like Figure 6A As shown, in one embodiment, the second current sensing circuit 200 corresponds to a conductor connection segment (such as...). Figure 6A (As shown by the gray lines), the first and second ends of the second current sensing circuit 200 (i.e., the conductor connection segment) are coupled to the second pair of pins of the power control circuit 300. Figure 6A In one embodiment, the power control circuit 300 is configured in a second configuration: when the second current sensing circuit 200 generates a judgment voltage Vx through the conductor connection segment, the second pair of pins corresponds to the ground pin PGND and the first pin P1 of the power control circuit 300. In a specific embodiment, the first end of the conductor connection segment is coupled to the ground pin PGND, and the second end of the conductor connection segment is coupled to the first pin P1. In this embodiment, the judgment voltage Vx corresponds to the cross voltage Vco between the first and second ends of the conductor connection segment. Specifically, the conductor connection segment has a connection resistance value Rco greater than 0. In this embodiment, the judgment voltage Vx (i.e., the cross voltage Vco) corresponds to the product of the connection resistance value Rco and the current Iout.

[0133] exist Figure 6A In this embodiment, the first pin P1 corresponds to the power limiting source pin PLPS. The power limiting source pin PLPS is used to receive the judgment voltage Vx (i.e., the transverse voltage Vco) for the power limiting source control procedure P100. (Related information...) Figure 6A For other details not specified, please refer to Figure 3A Explanation.

[0134] Figure 6B This diagram shows a power conversion circuit according to one embodiment of the present invention. Figure 6B The power conversion circuit 1006B is corresponding to Figure 6A A specific embodiment of the power conversion circuit 1006A. For example... Figure 6B As shown, in one embodiment, the power conversion circuit 1006B is configured as a flyback power conversion circuit. In one embodiment, the rectifier switch Q2 of the power stage circuit 500 is coupled to the path control switch QB. (Related information...) Figure 6B For any unspecified operational details, please refer to [link / reference]. Figure 3B and Figure 6A Explanation.

[0135] Figure 7 This diagram shows a power control circuit of a power conversion circuit according to an embodiment of the present invention. Figure 7 The power control circuit 3007 is corresponding to Figure 6A A specific embodiment of the power control circuit 300. Figure 7 The power control circuit 3007 is similar to Figure 4A The power control circuit of the 3004A is described below, highlighting the differences. For example... Figure 7 As shown, in one embodiment, the power control circuit 3007 further includes: a second amplifier circuit 350, coupled to a second pair of pins (i.e., the power limiting source pin PLPS and the ground pin PGND), for amplifying the voltage Vco across the conductor connection segment through the second pair of pins to generate a second amplified signal Va2. An analog-to-digital converter circuit 320 is further configured to convert the second amplified signal Va2 to generate a third digital amplified signal in the digital domain. A decision circuit 330 is further configured to execute the power limiting source control program P100 based on the digital output signal SD (i.e., the first digital amplified signal and the third digital amplified signal).

[0136] It should be noted that, in one embodiment, the analog-to-digital converter 320 converts the first amplified signal Va1 to generate a first digital amplified signal and converts the second amplified signal Va2 to generate a third digital amplified signal during the first and second conversion periods, respectively, and then generates a digital output signal SD based on the first digital amplified signal or the third digital amplified signal, respectively. In other words, the digital output signal SD generated by the analog-to-digital converter 320 corresponds to the first digital amplified signal during the first conversion period and to the third digital amplified signal during the second conversion period. (Related information...) Figure 7 For any unspecified operational details, please refer to [link / reference]. Figure 4A Explanation.

[0137] Please also refer to Figure 2B , Figure 6A and Figure 8 . Figure 8 This illustrates an embodiment of the present invention corresponding to... Figure 6A The operating waveform diagram of the power conversion circuit. In one embodiment, as shown... Figure 8 As shown, the current Iout gradually increases with time. At time t1, the current sensing voltage Vcs is lower than the sensing threshold Vcsth, and the absolute value of the judgment voltage Vx is higher than the absolute value of the judgment threshold Vxth. Figure 6AIn this embodiment, the voltage Vx is determined to be the cross-voltage Vco of the conductor connection segment, and the threshold Vxth is determined to be the cross-voltage threshold Vcoth. In this embodiment, the result of the first determination step S101 at time t1 is yes, at which point the first delay operation S103 is performed, that is, waiting for the first delay time Td1. Then at time t2, the power limiting source indication signal Vlps turns to a high level, indicating that the power limiting source operation S102 is performed. It should be noted that in Figure 6A In this embodiment, the cross voltage Vco of the conductor connection segment is less than 0, and the cross voltage threshold Vcoth is also less than 0. For example... Figure 8 As shown, the transverse voltage Vco decreases as the current Iout increases.

[0138] Figure 9A This diagram shows a power conversion circuit according to one embodiment of the present invention. Figure 9A The power conversion circuit 1009A is corresponding to Figure 1B An embodiment of the power conversion circuit 1001B. Figure 9A The power conversion circuit 1009A is similar to Figure 6A The power conversion circuit 1006A has the following differences. In one embodiment, as... Figure 9A As shown, the second end of the conductor connecting line segment is also coupled to the first pin P1 via a temperature sensing resistor RT. Figure 9A In one embodiment, the first pin P1 corresponds to the multiplexing pin PM (hereinafter referred to as the multiplexing pin PM). In one embodiment, the power control circuit 300 is used to receive the voltage Vco across the conductor connection segment through the multiplexing pin PM in a first time period to execute the power limiting source control program P100, and to provide a bias current to the temperature sensing resistor RT through the multiplexing pin PM in a second time period for over-temperature protection operation, as detailed below. Figure 9A For any unspecified operational details, please refer to [link / reference]. Figure 6A Explanation.

[0139] Figure 9B This diagram shows a power conversion circuit according to one embodiment of the present invention. Figure 9B The power conversion circuit 1009B is corresponding to Figure 9A A specific embodiment of the power conversion circuit 1009A. For example... Figure 9B As shown, in one embodiment, the power conversion circuit 1009B is configured as a flyback power conversion circuit. Those skilled in the art can infer from the foregoing description... Figure 9B Operational details.

[0140] Figure 10A and Figure 10B This diagram shows a power control circuit of a power conversion circuit in one embodiment of the present invention at different time periods. Figure 10A and Figure 10BThe power control circuit 3010 is corresponding to Figure 9A A specific embodiment of the power control circuit 300. Figure 10A and Figure 10B The power control circuit 3010 is similar to Figure 7 The power control circuit 3007 has the following differences. Figure 10A and Figure 10B As shown, in one embodiment, the power control circuit 3010 further includes a current source circuit 360, a first signal path switch S1, and a second signal path switch S2. In one embodiment, the current source circuit 360 is used to provide bias current. The first signal path switch S1 is coupled between the multiplexing pin PM and the second amplifier circuit 350. The second signal path switch S2 is coupled between the multiplexing pin PM and the current source circuit 360.

[0141] like Figure 10A As shown, in one embodiment, during the first time period, the first signal path switch S1 is turned on and the second signal path switch S2 is turned off. The second amplifier circuit 350 receives the voltage Vco across the conductor connection segment through the first signal path switch S1 and the multiplexing pin PM. The judgment circuit 330 is used to execute the power limiting source control program according to the digital output signal SD (i.e., the first digital amplified signal and the third digital amplified signal). Other operational details of the first time period are as follows... Figure 7 Same, please see Figure 7 Explanation.

[0142] like Figure 10B As shown, in one embodiment, during the second time period, the first signal path switch S1 is turned off and the second signal path switch S2 is turned on. The current source circuit 360 provides bias current to the temperature sensing resistor RT through the second signal path switch S2 and the multiplexing pin PM, thereby generating a voltage Vrt across the temperature sensing resistor RT. During this second time period, the analog-to-digital converter circuit 320 is also used to convert the voltage Vrt across the temperature sensing resistor RT to generate a digital temperature sensing signal in the digital domain. During the second time period, the determination circuit 330 is also used to determine whether the temperature of the temperature sensing resistor RT is higher than an over-temperature protection threshold based on the digital temperature sensing signal. Therefore, if the temperature of the temperature sensing resistor RT is higher than the over-temperature protection threshold, an over-temperature protection operation is performed.

[0143] Please also refer to Figure 2B , Figure 9A and Figure 11A . Figure 11A This illustrates an embodiment of the present invention corresponding to... Figure 9A The operating waveform diagram of the power conversion circuit. Figure 11A In one embodiment, the voltage Vx is determined to correspond to the cross-voltage Vco of the conductor connection segment, and the threshold Vxth corresponds to the cross-voltage threshold Vcoth. In one embodiment, as... Figure 11A As shown, the current Iout gradually increases over time. At time t3, the current sensing voltage Vcs is higher than the sensing threshold Vcsth, and the absolute value of the judgment voltage Vx is higher than the absolute value of the judgment threshold Vxth. In this embodiment, the judgment result of the first judgment step S101 at time t3 is negative, so the first judgment step S101 is repeated, without performing the first delay operation S103 and the power source limiting operation S102.

[0144] It should be noted that, in Figure 11A In this embodiment, the current Iout gradually increases over time, and the current sensing voltage Vcs also gradually increases over time, indicating that the sensing resistor Rcs is in a normal sensing state. At this time, the power control circuit 300 operates in a normal program, determining whether to perform overcurrent protection based on the comparison between the current sensing voltage Vcs and the overcurrent threshold voltage Vocpth. In this embodiment, as... Figure 11A As shown, the current sensing voltage Vcs did not exceed the overcurrent threshold voltage Vocpth, therefore overcurrent protection was not activated. It should also be noted that... Figure 9A In the embodiment, the multiplexing pin PM performs current sensing and temperature sensing in the first time period (e.g., Tp1 and the corresponding subsequent time period) and the second time period (e.g., the corresponding subsequent time period of Tp2), respectively. Therefore, in Figure 11A In the waveform diagram, the voltage across the conductor connection segment received from the multiplexing pin PM and the voltage across the temperature sensing resistor RT are discontinuous waveforms. It should be noted that, in one embodiment, the resistance value of the temperature sensing resistor RT within the measured temperature range is much greater than the resistance value Rco of the conductor connection segment (e.g., more than 100 times).

[0145] Please continue reading Figure 9A and Figure 11A In one specific embodiment, the temperature sensing resistor RT has a negative temperature coefficient; the lower the voltage Vrt across the temperature sensing resistor RT, the higher the corresponding temperature. For example... Figure 11A As shown, in one embodiment, at time t1, the trans-voltage Vrt of the temperature sensing resistor RT exceeds (below) the temperature threshold Vtth. After a third delay time Td3, the over-temperature indication signal Votp turns to a high level, indicating that an over-temperature protection operation is performed.

[0146] Please also refer to Figure 2B , Figure 9A and Figure 11B . Figure 11B Another embodiment of the present invention corresponds to Figure 9A The operating waveform diagram of the power conversion circuit. Figure 11BIn one embodiment, the voltage Vx is determined to correspond to the cross-voltage Vco of the conductor connection segment, and the threshold Vxth corresponds to the cross-voltage threshold Vcoth. In one embodiment, as... Figure 11B As shown, at time t1, the current sensing voltage Vcs is lower than the sensing threshold Vcsth, and the absolute value of the judgment voltage Vx is higher than the absolute value of the judgment threshold Vxth. In this embodiment, the judgment result of the first judgment step S101 at time t1 is yes, at which point the first delay operation S103 is performed, that is, waiting for the first delay time Td1. Then at time t2, the power limiting source indication signal Vlps turns to a high level, indicating that the power limiting source operation S102 is performed. Figure 11B In this embodiment, the voltage across the temperature sensing resistor RT, Vrt, does not exceed (or fall below) the temperature threshold Vtth, therefore no over-temperature protection operation is performed. It should be noted that the word "exceeds" here, when the temperature sensing resistor RT has a negative temperature coefficient, means that the voltage across the temperature sensing resistor RT "decreases and falls below" the temperature threshold Vtth. On the other hand, when the temperature sensing resistor RT has a positive temperature coefficient, it means that the voltage across the temperature sensing resistor RT "increases and rises above" the temperature threshold Vtth. Both indicate that the temperature of the temperature sensing resistor RT is higher than the aforementioned over-temperature protection threshold.

[0147] Figure 12 This diagram shows the operation flowchart of the power source limiting control program of the power conversion circuit in one embodiment of the present invention. Figure 12 The flowchart is similar to Figure 2B The flowchart is shown below, and the differences are explained. In one embodiment, the power limiting source control program P100 further includes: a second judgment step S201 and a second delay operation S202. In one embodiment, the second judgment step S201 includes: judging whether the path control switch QB is turned on. The second delay operation S202 includes: waiting for a second delay time Td2. In one embodiment, when the judgment result of the second judgment step S201 is yes, the second delay operation S202 is performed. In another embodiment, when the judgment result of the second judgment step S201 is no, the second judgment step S201 is repeated until the judgment result of the second judgment step S201 is yes, at which point the second delay operation S202 is performed. In this embodiment, the first judgment step S101 operates after the second judgment step S201, and more specifically, the first judgment step S101 operates after the second delay operation S202.

[0148] It should be noted that, Figure 12 The operation flowchart applies to all the embodiments of the present invention described above. It should also be noted that, since the current Iout begins to form the current path Ipth when the path control switch QB is turned on, therefore... Figure 12 The operating procedure ensures the normal operation of the power limiting source control program P100.

[0149] The present invention has been described above with reference to preferred embodiments. However, the above description is only intended to facilitate understanding of the invention by those skilled in the art and is not intended to limit the broadest scope of the invention. The described embodiments are not limited to individual application and can also be used in combination. For example, two or more embodiments can be used in combination, and some components of one embodiment can be used to replace corresponding components in another embodiment. Furthermore, within the same spirit of the invention, those skilled in the art can conceive of various equivalent changes and combinations. For example, the phrase "processing or calculating based on a signal or generating an output result" in the present invention is not limited to the signal itself, but also includes, when necessary, performing voltage-to-current conversion, current-to-voltage conversion, and / or proportional conversion on the signal, and then processing or calculating based on the converted signal to generate an output result. Therefore, within the same spirit of the invention, those skilled in the art can conceive of various equivalent changes and combinations, and there are many combinations, which will not be listed here. Therefore, the scope of the present invention should cover the above and all other equivalent changes.

Claims

1. A power conversion circuit for generating a supply voltage based on an input voltage, characterized in that, Include: A path control switch, coupled between the supply voltage and a bus power supply voltage, is used to control a conduction path from the supply voltage to the bus power supply voltage, wherein the bus power supply voltage is used to provide a current to a load. A first current sensing circuit includes a sensing resistor connected in series with a current path of the current, for generating a current sensing voltage based on the current. A second current sensing circuit includes a path control switch or a conductor connecting line segment connected in series with the current path, for generating a judgment voltage based on the current; as well as A power control circuit is used to control the path control switch and to execute a power-limiting source control program based on the current-sensed voltage and the determined voltage. The power-limiting source control program includes: The first judgment step: determining whether the current sensing voltage is lower than a sensing threshold and whether the absolute value of the judgment voltage is higher than the absolute value of a judgment threshold; and One-way power source operation: limits the output power associated with the current; When the result of the first judgment step is yes, the power-limiting source operation is performed.

2. The power conversion circuit as described in claim 1, wherein, The power control circuit is configured as an integrated circuit; A first terminal and a second terminal of the first current sensing circuit are coupled to a first pair of pins of the power control circuit, wherein the first pair of pins corresponds to a sensing pin and a ground pin of the power control circuit. A first terminal and a second terminal of the second current sensing circuit are coupled to a second pair of pins of the power control circuit. The power control circuit is configured as one of the following: First configuration: When the second current sensing circuit generates the judgment voltage through the path control switch, the second pair of pins corresponds to a power supply pin and a bus pin of the power control circuit, wherein a first terminal of the path control switch is coupled to the power supply pin, a second terminal of the path control switch is coupled to the bus pin, and a control terminal of the path control switch is coupled to a control pin of the power control circuit, wherein the judgment voltage corresponds to a conduction voltage when the path control switch is turned on; or Second configuration: When the second current sensing circuit generates the judgment voltage through the conductor connection segment, the second pair of pins corresponds to the ground pin and a first pin of the power control circuit, wherein a first end of the conductor connection segment is coupled to the ground pin, and a second end of the conductor connection segment is coupled to the first pin, wherein the judgment voltage corresponds to a voltage across the first end and the second end of the conductor connection segment.

3. The power conversion circuit as described in claim 2, wherein, The power control circuit includes: A first amplifier circuit, coupled to the first pair of pins, is used to amplify the current sensing voltage to generate a first amplified signal; An analog-to-digital converter circuit is used to convert the first amplified signal to generate a first digital amplified signal in the digital domain; and A judgment circuit is used to execute the power limiting source control program based on the first digital amplified signal and the judgment voltage.

4. The power conversion circuit as described in claim 3, wherein, When the power control circuit is configured in the first configuration: The analog-to-digital converter circuit is also used to convert the on-voltage to generate a second digitally amplified signal in the digital domain; and The judgment circuit is also used to execute the power limiting source control program based on the first digital amplified signal and the second digital amplified signal; Or, when the power control circuit is configured in the first configuration: The power control circuit further includes a comparator for comparing the on-state voltage with the judgment threshold to generate a comparison signal; and The judgment circuit is also used to execute the power limiting source control program based on the first digital amplified signal and the comparison signal.

5. The power conversion circuit as described in claim 1, wherein, The power-limiting source control program also includes a first delay operation: waiting for a first delay time; If the result of the first judgment step is yes, the first delay operation is also performed, followed by the power limiting source operation.

6. The power conversion circuit as described in claim 1, wherein, The power-limiting source control program also includes: The second judgment step: determine whether the path control switch is on; and Second delay operation: Wait for a second delay time; If the result of the second judgment step is yes, the second delay operation is performed, and then the first judgment step is performed.

7. The power conversion circuit as described in claim 1, wherein, The operation of the power limiting source includes: turning off the path control switch or increasing the on-resistance value of the path control switch.

8. The power conversion circuit as described in claim 1, wherein, The current sensing threshold corresponding to the sensing threshold is lower than the absolute value of the current judgment threshold corresponding to the judgment threshold.

9. The power conversion circuit as described in claim 3, wherein, When the power control circuit is configured in the second configuration, the power control circuit further includes: A second amplifier circuit is used to amplify the voltage across the conductor connection segment through the second pair of pins to generate a second amplified signal; The analog-to-digital conversion circuit is also used to convert the second amplified signal to generate a third digital amplified signal in the digital domain; The judgment circuit is also used to execute the power limiting source control program based on the first digital amplified signal and the third digital amplified signal.

10. The power conversion circuit as described in claim 9, wherein, The second end of the conductor connecting line segment is also coupled to the first pin via a temperature sensing resistor, wherein the power control circuit further includes: A current source circuit is used to provide a bias current; During a first time period, the second amplifier circuit receives the voltage across the conductor connection segment through the first pin, and the judgment circuit is used to execute the power limiting source control program based on the first digital amplified signal and the third digital amplified signal. During a second time period, the current source circuit provides the bias current to the temperature sensing resistor through the first pin, thereby generating a voltage across the temperature sensing resistor. During the second time period, the analog-to-digital conversion circuit is also used to convert the voltage across the temperature sensing resistor to generate a digital temperature sensing signal in the digital domain. During the second time period, the judgment circuit is also used to determine whether the temperature of the temperature sensing resistor is higher than an over-temperature protection threshold based on the digital temperature sensing signal.

11. A control method for controlling a power conversion circuit to generate a supply voltage based on an input voltage, characterized in that, Include: A path control switch controls a conduction path from the supply voltage to a bus power supply voltage, wherein the bus power supply voltage is used to provide a current to a load. Based on the current, a current sensing voltage is generated in a first current sensing circuit, wherein the first current sensing circuit includes a sensing resistor connected in series with a current path of the current. Based on the current, a judgment voltage is generated in a second current sensing circuit, wherein the second current sensing circuit includes a path control switch or a conductor connecting line segment connected in series with the current path. as well as A power source control program is executed based on the current-sensing voltage and the determined voltage. The power-limiting source control program includes: The first judgment step: determining whether the current sensing voltage is lower than a sensing threshold and whether the absolute value of the judgment voltage is higher than the absolute value of a judgment threshold; and One-way power source operation: limits the output power associated with the current; When the result of the first judgment step is yes, the power-limiting source operation is performed.

12. The control method as described in claim 11, wherein, Also includes: Amplifying the current-sensing voltage generates a first amplified signal; The first amplified signal is converted to generate a first digital amplified signal in the digital domain; and The power limiting source control program is executed based on the first digital amplified signal and the determined voltage.

13. The control method as described in claim 12, wherein, When the second current sensing circuit includes a path control switch series coupled to the current path, the control method further includes: Convert the on-state voltage when the path control switch is turned on to generate a second digitally amplified signal in the digital domain; and The power limiting source control program is executed based on the first digital amplified signal and the second digital amplified signal; or The on-state voltage is compared with the threshold value to generate a comparison signal; and The power limiting source control program is executed based on the first digital amplified signal and the comparison signal.

14. The control method as described in claim 11, wherein, The power-limiting source control program also includes a first delay operation: waiting for a first delay time; If the result of the first judgment step is yes, the first delay operation is also performed, followed by the power limiting source operation.

15. The control method as described in claim 11, wherein, The power-limiting source control program also includes: The second judgment step: determine whether the path control switch is on; and Second delay operation: Wait for a second delay time; If the result of the second judgment step is yes, the second delay operation is performed, and then the first judgment step is performed.

16. The control method as described in claim 11, wherein, The operation of the power limiting source includes: turning off the path control switch or increasing the on-resistance value of the path control switch.

17. The control method as described in claim 11, wherein, The current sensing threshold corresponding to the sensing threshold is lower than the absolute value of the current judgment threshold corresponding to the judgment threshold.

18. The control method as described in claim 12, wherein, When the second current sensing circuit includes the conductor connection segment connected in series with the current path, the control method further includes: Amplify a voltage across the conductor connecting segment to generate a second amplified signal; The second amplified signal is converted to generate a third digital amplified signal in the digital domain; and The power limiting source control program is executed based on the first digital amplified signal and the third digital amplified signal.

19. The control method as described in claim 18, wherein, The conductor connection segment is also coupled to a temperature sensing resistor, wherein the control method further includes: Provide a bias current; During a first time period, the voltage across the conductor connection segment is received, and the power limiting source control program is executed based on the first digital amplified signal and the third digital amplified signal. During a second time period, the bias current is provided to the temperature sensing resistor, thereby generating a voltage across the temperature sensing resistor; and During the second time period, the voltage across the temperature sensing resistor is converted to generate a digital temperature sensing signal in the digital domain, and the temperature of the temperature sensing resistor is determined based on the digital temperature sensing signal to determine whether the temperature is higher than an over-temperature protection threshold.

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