Load insertion detection circuit, control method thereof and multi-port charger

Abstract

The invention discloses a load insertion detection circuit, a control method thereof and a multi-port charger, and belongs to the technical field of multi-port charging. The load insertion detection circuit comprises a comparison unit, a first input end is connected with a load access node, a second input end is used for accessing a reference voltage, and the comparison unit outputs a first signal when the voltage of the first input end is greater than the voltage of the second input end; each pull-up circuit comprises a switch and a resistor which are connected in series, the first end of each pull-up circuit is electrically connected with the same power supply voltage node, the second end of each pull-up circuit is electrically connected with the load access node, and the resistance values of the resistors are different; the control circuit is electrically connected with the driving end of each switch and the output end of the comparison unit, the control circuit controls the corresponding switches to be switched on according to the sequence that the resistance values of the resistors are decreased progressively until the comparison unit outputs the first signal, the switching-on state of the switch which is switched on currently is maintained, load insertion detection is carried out, the detection range is enlarged, and the anti-interference performance is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of multi-port charging, and in particular relates to a load insertion detection circuit and a control method thereof, and a multi-port charger. Background Art

[0002] In recent years, with the advancement of USB fast charging technology, multi-port charging devices, such as power banks and power strips, have emerged, meeting the need for simultaneous charging of multiple devices and providing significant convenience for users. Load insertion and removal recognition, a key technology in multi-port charging management, is primarily used to identify the insertion and removal of loads, providing essential support for dynamic power distribution and intelligent path control. Traditional load insertion detection circuits often suffer from drawbacks, manifested in a narrow load detection range or poor anti-interference performance. Summary of the Invention

[0003] This application aims to solve at least one of the technical problems existing in the prior art. To this end, this application proposes a load insertion detection circuit and control method thereof, and a multi-port charger, which not only expands the detection range of load access but also improves anti-interference performance.

[0004] In a first aspect, the present application provides a load insertion detection circuit, comprising:

[0005] a comparison unit, wherein a first input terminal of the comparison unit is connected to the load access node, a second input terminal of the comparison unit is used to access a reference voltage, and the comparison unit is configured to output a first signal when a voltage at the first input terminal is greater than a voltage at the second input terminal;

[0006] Multiple pull-up circuits, each pull-up circuit comprising a switch and a resistor connected in series, a first end of each pull-up circuit being electrically connected to the same supply voltage node, a second end of each pull-up circuit being electrically connected to a load access node, and a resistance value of each resistor in each pull-up circuit being different;

[0007] The control circuit is electrically connected to the driving end of each switch and the output end of the comparison unit, respectively. The control circuit is configured to control the corresponding switches to be turned on in the order of decreasing resistance values of the resistors in the pull-up circuit until the comparison unit outputs the first signal, and maintain the on state of the currently turned-on switch to perform load insertion detection.

[0008] According to the load insertion detection circuit of the present application, the larger the resistance of the resistor in the pull-up circuit, the weaker the pull-up capability. When the load access node is connected to a charging line with leakage, the leakage resistance introduced by the leakage line will form a voltage divider with the resistance in the pull-up circuit, so that the voltage of the load access node cannot reach the reference voltage. At this time, the control circuit switches to a pull-up circuit with stronger pull-up capability until the voltage connected to the load access node is higher than the reference voltage, so that when another device is inserted into the leakage charging line, the insertion of the device can be effectively identified; the large-resistance pull-up circuit can cover a wider load insertion detection range, while the small-resistance pull-up circuit can suppress stronger interference, which not only expands the detection range of load access, but also improves anti-interference performance.

[0009] According to one embodiment of the present application, the comparison unit includes:

[0010] a first comparator, wherein a positive input terminal of the first comparator is connected to the load access node, and a negative input terminal of the first comparator is used to access a first reference voltage;

[0011] a second comparator, wherein a positive phase input terminal of the second comparator is connected to the load access node, and a negative phase input terminal of the second comparator is used to access a second reference voltage, and the second reference voltage is less than the first reference voltage;

[0012] The control circuit is electrically connected to the output end of the first comparator and the output end of the second comparator, respectively. The control circuit is configured to control the corresponding switches to be turned on in the order of decreasing resistance values of the resistors in the pull-up circuit until the first comparator outputs a high-level signal and maintains the on state of the currently turned-on switch. When the signal output by the second comparator changes from a high-level signal to a low-level signal, it is determined that a load is inserted into the load access node.

[0013] According to one embodiment of the present application, the load insertion detection circuit further includes:

[0014] a first switch circuit, wherein a first terminal of the first switch circuit is electrically connected to a first reference voltage node, a second terminal of the first switch circuit is electrically connected to a negative phase input terminal of the first comparator, and the first reference voltage node is configured to provide a first reference voltage;

[0015] A second switching circuit, a first end of the second switching circuit is electrically connected to a third reference voltage node, a second end of the third switching circuit is electrically connected to a negative input terminal of the first comparator, and the third reference voltage node is configured to provide a third reference voltage, which is greater than the first reference voltage.

[0016] In a second aspect, the present application provides a control method for a load insertion detection circuit, which is applied to the aforementioned load insertion detection circuit. The control method includes:

[0017] Controlling the switch in the pull-up circuit to be turned on in descending order of resistance value until the comparison unit outputs a first signal;

[0018] The currently turned-on switch is controlled to maintain the turned-on state and perform load insertion detection.

[0019] According to one embodiment of the present application, a currently turned-on switch is controlled to maintain the turned-on state to perform load insertion detection, and a comparison unit is configured to output a second signal when the voltage at the first input terminal is less than the voltage at the second input terminal. The control method includes:

[0020] When the signal output by the comparison unit changes from the first signal to the second signal, it is determined that a load is inserted into the load access node.

[0021] According to the control method of the load insertion detection circuit of the present application, when the load access node is connected to a charging line with leakage, the leakage resistance introduced by the leakage line will form a voltage divider with the resistance in the pull-up circuit, so that the voltage of the load access node cannot reach the reference voltage. At this time, the control circuit switches to a pull-up circuit with stronger pull-up capability until the voltage connected to the load access node is higher than the reference voltage, so that when another device is inserted into the leakage charging line, the insertion of the device can be effectively identified; the large-resistance pull-up circuit can cover a wider load insertion detection range, while the small-resistance pull-up circuit can suppress stronger interference, which not only expands the detection range of load access, but also improves anti-interference performance.

[0022] According to one embodiment of the present application, the comparison unit includes a first comparator and a second comparator, the positive phase input terminal of the first comparator is electrically connected to the load access node, the negative phase input terminal of the first comparator is used to access a first reference voltage, the positive phase input terminal of the second comparator is electrically connected to the load access node, the negative phase input terminal of the second comparator is used to access a second reference voltage, and the second reference voltage is less than the first reference voltage. The control method includes:

[0023] Controlling the switch in the pull-up circuit to be turned on in descending order of resistance value until the first comparator outputs a high level signal;

[0024] The currently turned-on switch is controlled to maintain the turned-on state, and when the signal output by the second comparator changes from a high-level signal to a low-level signal, it is determined that a load is inserted into the load access node.

[0025] According to one embodiment of the present application, controlling the switches in the pull-up circuit to be turned on in descending order of resistance until the first comparator outputs a high-level signal further includes:

[0026] Controlling the negative input terminal of the first comparator to be connected to a third reference voltage, where the third reference voltage is greater than the first reference voltage;

[0027] When the first comparator outputs a high-level signal and the resistance value of the resistor in the currently turned-on pull-up circuit is not the maximum resistance value, controlling the switch in the currently turned-on pull-up circuit to be turned off according to a preset period, and controlling the switch in the pull-up circuit where the resistor with the largest resistance value is located to be turned on;

[0028] When the first comparator still outputs a high-level signal, the negative input terminal of the first comparator is controlled to be connected to the first reference voltage, and the switch in the pull-up circuit is controlled to be turned on in the order of decreasing resistance until the first comparator outputs a high-level signal.

[0029] According to one embodiment of the present application, when the first comparator outputs a high-level signal and the resistance value of the resistor in the currently turned-on pull-up circuit is not the maximum resistance value, after controlling the switch in the currently turned-on pull-up circuit to be turned off according to a preset period and controlling the switch in the pull-up circuit where the resistor with the largest resistance is located to be turned on, the method further includes:

[0030] When the output signal of the first comparator changes from a high level signal to a low level signal, the switch in the pull-up circuit where the resistor with the largest resistance is located is controlled to be disconnected, and the switch in the previously disconnected pull-up circuit is controlled to be turned on.

[0031] According to one embodiment of the present application, the control method further includes:

[0032] After the switch in the pull-up circuit with the smallest resistance is turned on, if the comparison unit output signal is still a low level signal, the switch in the pull-up circuit with the largest resistance is controlled to be turned on, and the switches in the remaining pull-up circuits are controlled to be turned off.

[0033] In a third aspect, the present application provides a multi-port charger, comprising multiple USB ports and multiple aforementioned load insertion detection circuits, wherein the load access node of each load insertion detection circuit is electrically connected to a corresponding USB port.

[0034] According to the multi-port charger of the present application, the larger the resistance of the resistor in the pull-up circuit, the weaker the pull-up capability. When the load access node is connected to a charging line with leakage, the leakage resistance introduced by the leakage line will form a voltage divider with the resistance in the pull-up circuit, so that the voltage of the load access node cannot reach the reference voltage. At this time, the control circuit switches to a pull-up circuit with stronger pull-up capability until the voltage connected to the load access node is higher than the reference voltage, so that when another device is inserted into the leaking charging line, the insertion of the device can be effectively identified; the large-resistance pull-up circuit can cover a wider load insertion detection range, while the small-resistance pull-up circuit can suppress stronger interference, which not only expands the detection range of load access, but also improves anti-interference performance.

[0035] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0037] Figure 1 This is one of the circuit diagrams of a load insertion detection circuit in the related art;

[0038] Figure 2 This is the second circuit diagram of the load insertion detection circuit in the related art;

[0039] Figure 3 is a structural block diagram of a load insertion detection circuit provided in an embodiment of the present application;

[0040] Figure 4 This is one of the circuit diagrams of the load insertion detection circuit provided in the embodiment of the present application;

[0041] Figure 5 This is the second circuit diagram of the load insertion detection circuit provided in an embodiment of the present application;

[0042] Figure 6 This is the third flowchart of the control method of the load insertion detection circuit provided in an embodiment of the present application.

[0043] Reference numerals:

[0044] Comparing unit 110, pull-up circuit 120, first switching circuit 131, second switching circuit 132, third switching circuit 133, load access node Rc, first to second comparators A1-A2, power supply voltage node VCC, first to Nth switches S1-SN, first to Nth resistors R1-RN, first to third reference voltages Vth1-Vth3. DETAILED DESCRIPTION

[0045] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0046] In the following description, a "circuit" refers to a conductive loop consisting of at least one element or subcircuit connected electrically or electromagnetically. When an element or circuit is said to be "coupled to" or "connected to" another element, or when an element / circuit is said to be "coupled to" or "connected between" two nodes, it can be directly coupled or connected to the other element or there can be intervening elements. The connection between the elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there are no intervening elements between the two elements.

[0047] In the description, the terms "first," "second," etc. are used to distinguish similar objects, not to describe a particular order or precedence. It should be understood that the numerical descriptors used in this manner are interchangeable where appropriate, so that the embodiments of the present application can be implemented in an order other than that illustrated or described herein, and that the objects distinguished by "first," "second," etc. are generally of a class and do not limit the number of objects; for example, the first object can be one or more. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects connected are in an "or" relationship.

[0048] In addition, descriptions with reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples.

[0049] In recent years, with the advancement of USB fast-charging technology, multi-port charging devices, such as power banks and power strips, have emerged, meeting the need for simultaneous charging of multiple devices and providing significant convenience for users. Load plug-in and plug-out recognition, a key technology in multi-port charging management, is primarily used to identify the insertion and removal of loads, providing essential support for dynamic power distribution and intelligent path control.

[0050] Figure 1 and Figure 2 The circuit diagram of the load insertion detection circuit in the related art is shown. There are two main implementation methods for common load insertion identification. Figure 1The first is to implement it by using a resistor pull-up method. The load insertion detection circuit uses the voltage drop of the load access node when the load is inserted to identify the load insertion. The comparator judgment threshold is V0, the resistance of the pull-up resistor is R0, and the voltage of the power supply voltage node is VCC. The load insertion detection circuit can effectively identify a resistance value that is less than V0*R0 / (VCC-V0). For small-value pull-up resistors, the effective identification resistance range is small, and the connection of some loads cannot be identified. For large-value pull-up resistors, although the identification resistance range is large, when a leakage wire is inserted, the leakage wire itself will introduce additional resistance, thereby lowering the voltage of the load access node. At this time, the load insertion detection circuit may mistakenly judge that there is a load connected. If a mobile phone or other device to be charged is connected, the load insertion detection circuit cannot effectively identify it. In addition, for a mobile power bank with multiple ports, such as a mobile power bank with A+C ports, if a leakage wire is inserted into port A, the load insertion detection circuit connected to port A will mistakenly judge that there is a load connected to port A. At this time, if a mobile phone or other device to be charged is connected to port C, fast charging will not be possible.

[0051] Reference Figure 2 The second method for load insertion recognition is to charge the capacitor through a current source, using the voltage drop at the load access node when the load is inserted to identify the load insertion. To reduce power consumption when only the leaky wire is plugged in without a mobile phone or other device, the current source current is often relatively small. This implementation method is also unable to effectively identify the device insertion when the leaky wire is plugged in and the mobile phone or other device is also plugged in. For mobile power banks with multiple ports, if only the leaky wire is plugged in to one port, the other ports will not be able to fast charge.

[0052] Figure 3 FIG1 shows a structural block diagram of a load insertion detection circuit provided by an embodiment of the present application. Figure 3 One embodiment of the present application provides a load insertion detection circuit, comprising: a comparison unit 110, a plurality of pull-up circuits 120, and a control circuit (not shown). The first input terminal of the comparison unit 110 is connected to the load access node Rc, and the second input terminal of the comparison unit 110 is used to access a reference voltage. The comparison unit 110 is configured to output a first signal when the voltage at the first input terminal is greater than the voltage at the second input terminal. The pull-up circuit 120 includes a switch and a resistor connected in series. The first terminal of each pull-up circuit 120 is electrically connected to the same power supply voltage node VCC, and the second terminal of each pull-up circuit 120 is electrically connected to the load access node Rc. The resistance value of each resistor in the pull-up circuit 120 is different. The control circuit is electrically connected to the driving terminal of each switch and the output terminal of the comparison unit 110 respectively. The control circuit is configured to control the switches to be turned on in the order of decreasing resistance value of the resistors in the pull-up circuit 120 until the comparison unit 110 outputs the first signal and maintains the on state of the currently turned-on switch to perform load insertion detection.

[0053] The comparison unit 110 has two input terminals and one output terminal. The first input terminal and the second input terminal are respectively used to receive different voltage signals for comparison operations and output corresponding signals. The control circuit can determine the magnitude relationship of the voltages connected to the first input terminal and the second input terminal based on the output signal of the comparison unit 110.

[0054] The specific structure of the comparison unit 110 can be selected according to the actual application scenario and is not limited here. For example, the comparison unit 110 may include a comparator, the positive input terminal of the comparator being the first input terminal of the comparison unit 110, and the negative input terminal of the comparator being the second input terminal of the comparison unit 110. When the voltage connected to the positive input terminal of the comparator is greater than the voltage connected to the negative input terminal, the comparator outputs a high-level signal; otherwise, the comparator outputs a low-level signal.

[0055] The load access node Rc is a node for connecting a load. When a load is connected, the voltage of the load access node Rc changes according to the characteristics of the load. The comparison unit 110 determines whether the load is connected by comparing the voltage received at the first input terminal with the reference voltage received at the second input terminal.

[0056] Each pull-up circuit 120 consists of a switch and a resistor connected in series. A first terminal of each pull-up circuit 120 is electrically connected to a supply voltage node VCC, which provides a stable voltage source for the circuit and the necessary power for the entire circuit system. A second terminal of each pull-up circuit 120 is electrically connected to a first input terminal of the comparison unit 110 and a load access node Rc, respectively. Pull-up circuits 120 are primarily used to raise the voltage at the load access node Rc.

[0057] The resistors in each pull-up circuit 120 have different resistance values. Resistors are primarily used for voltage division in circuits, and resistors of different resistance values affect the voltage distribution within the circuit. The larger the resistance value of a pull-up circuit 120, the weaker the pull-up capability of the pull-up circuit 120. The smaller the resistance value of a pull-up circuit 120, the stronger the pull-up capability of the pull-up circuit 120.

[0058] The switch can switch between an on state and an off state, mainly used to realize the conduction and shutdown of the corresponding pull-up circuit 120. The specific type of each switch can be selected according to the actual application scenario and is not limited here. For example, each switch can be a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), an IGBT (Insulate-Gate Bipolar Transistor), or a bipolar transistor.

[0059] The control circuit is electrically connected to the driving terminal of each switch and the output terminal of the comparison unit 110. The control circuit is primarily used to control the on and off states of the switches in the pull-up circuit 120, and to determine whether the load insertion detection circuit meets the detection conditions based on the output signal of the comparison unit 110. If the load insertion detection circuit meets the detection conditions, the control circuit also determines whether a load is inserted based on the output signal of the comparison unit 110.

[0060] It should be noted that the specific types of the first signal and the second signal can be determined according to the actual application scenario and are not limited here. For example, the first signal is a high-level signal and the second signal is a low-level signal; or the first signal is a low-level signal and the second signal is a high-level signal. The following is an example in which when the voltage at the first input terminal of the comparison unit 110 is higher than the voltage at the second input terminal, the comparison unit 110 outputs a first signal (high-level signal); and when the voltage at the first input terminal is lower than the voltage at the second input terminal, the comparison unit 110 outputs a second signal (low-level signal).

[0061] The load insertion detection circuit satisfies the detection condition when the voltage at the load access node Rc (the first input terminal of the comparison unit 110) is higher than the voltage at the second input terminal (the reference voltage). When the voltage at the load access node Rc is higher than the voltage at the second input terminal, the comparison unit 110 outputs a high-level signal. When a load is inserted into the load access node Rc, the voltage drops below the reference voltage, and the output signal of the comparison unit 110 changes from a high-level signal to a low-level signal. The change in the output signal of the comparison unit 110 can be used to determine whether a load is connected.

[0062] The control circuit first turns on the switch in pull-up circuit 120 with the largest resistance. Pull-up circuit 120 with the largest resistance has the weakest pull-up capability. At this point, if no device is connected to load access node Rc, the turned-on pull-up circuit 120 can raise the voltage at load access node Rc to a level greater than the reference voltage. This means that the voltage at the first input terminal of comparison unit 110 is higher than the voltage at the second input terminal. Comparison unit 110 outputs a first signal, and the first signal persists for a first delay time, indicating that the load insertion detection circuit has met the detection conditions. Performing load insertion detection in this scenario can cover a wider load insertion detection range.

[0063] The first delay time is a preset period of time used to eliminate misjudgments caused by transient circuit changes or other interference factors. The control circuit determines that the load insertion detection circuit meets the detection conditions only if the first signal remains stable for the first delay time. The specific value of the first delay time can be selected based on the actual application scenario and is not limited here. For example, the first delay time can be 5ms or 6ms.

[0064] If the load access node Rc is connected to a leakage wire, the resistance introduced by the leakage wire will form a voltage divider with the weak pull-up circuit. The pull-up circuit 120 with the weakest pull-up capability cannot raise the load access node Rc to a voltage greater than the reference voltage, causing the voltage at the load access node Rc to be less than the reference voltage. The comparison unit 110 outputs a second signal, and it can be determined that the load insertion detection circuit does not meet the detection conditions.

[0065] If the load insertion detection circuit does not meet the detection conditions, the control circuit controls the switch in the pull-up circuit 120 with the smaller resistance to turn on until the pull-up capability of the turned-on pull-up circuit 120 is sufficient to raise the voltage at the load access node Rc to a level greater than the reference voltage. In other words, if the comparison unit 110 outputs a first signal, the load insertion detection circuit is determined to have met the detection conditions. If the load insertion detection circuit meets the detection conditions, the corresponding pull-up circuit 120 remains turned on, and load insertion detection is performed. If the output signal of the comparison unit 110 changes from the first signal to the second signal, and the second signal remains for the second delay time, it is determined that a load has been inserted into the load access node Rc, and a load insertion signal is generated.

[0066] The second delay time is also a preset time period used to eliminate misjudgments caused by transient circuit changes or other interference factors. The specific value of the second delay time can be selected according to the actual application scenario and is not limited here. For example, the second delay time can be 5ms or 6ms.

[0067] It should be noted that when the pull-up circuit 120 with the weakest pull-up capability is insufficient to raise the voltage at node Rc connected to the load to a value greater than the reference voltage, the switch in the pull-up circuit 120 with the weakest pull-up capability can be turned off or remain on when the pull-up circuit 120 with the smaller on-resistance is turned on. This is because if the switch in the pull-up circuit 120 with the weakest pull-up capability remains on when the pull-up circuit 120 with the smaller on-resistance is turned on, it is equivalent to connecting the resistors of the two pull-up circuits 120 in parallel. The total resistance of the parallel connection is less than the smaller of the two resistors, thus increasing the pull-up capability until the load insertion detection circuit meets the detection conditions.

[0068] According to the load insertion detection circuit of the present application, the larger the resistance of the resistor in the pull-up circuit 120, the weaker the pull-up capability. When the load access node Rc is connected to a charging line with leakage, the leakage resistance introduced by the leakage line will form a voltage divider with the resistance in the pull-up circuit 120, so that the voltage of the load access node cannot reach the reference voltage. At this time, the control circuit switches to a pull-up circuit with stronger pull-up capability until the voltage connected to the load access node Rc is higher than the reference voltage, so that when another device is inserted into the leakage charging line, the insertion of the device can be effectively identified; the large-resistance pull-up circuit can cover a wider load insertion detection range, while the small-resistance pull-up circuit can suppress stronger interference, which not only expands the detection range of load access, but also improves anti-interference performance.

[0069] Figure 4 FIG1 shows a circuit diagram of a load insertion detection circuit provided by an embodiment of the present application. Figure 4 In some embodiments, the comparison unit 110 includes a first comparator A1, a positive input terminal of the first comparator A1 is electrically connected to the load access node Rc and the second end of each pull-up circuit 120; and a negative input terminal of the first comparator A1 is used to access the first reference voltage Vth1.

[0070] The first comparator A1 can be used to determine whether the load insertion detection circuit meets the detection conditions. The following description uses the load insertion detection circuit as an example, where the circuit includes two pull-up circuits 120 , one of which has a larger resistance (hereinafter referred to as a weak pull-up circuit) and the other has a smaller resistance (hereinafter referred to as a strong pull-up circuit).

[0071] When the weak pull-up circuit is turned on, if the first comparator A1 outputs a high-level signal and persists for the first delay time, it indicates that the voltage at the load access node Rc is greater than the first reference voltage Vth1, thereby determining that the load insertion detection circuit meets the detection condition. If the first comparator A1 outputs a low-level signal or outputs a high-level signal for a period that does not persist for the first delay time, it indicates that the voltage at the load access node Rc is less than the first reference voltage Vth1, thereby determining that the load insertion detection circuit does not meet the detection condition. In this case, the strong pull-up circuit is turned on to retest whether the load insertion detection circuit meets the detection condition. It should be noted that when the strong pull-up circuit is turned on, the weak pull-up circuit can be turned on or off. The following description uses the example of only one pull-up circuit 120 being turned on at the same time.

[0072] When the strong pull-up circuit is turned on, if the first comparator A1 outputs a high-level signal and lasts for the first delay time, it indicates that the voltage at the load access node Rc is greater than the first reference voltage Vth1, and thus it can be determined that the load insertion detection circuit meets the detection condition; if the first comparator A1 outputs a low-level signal or outputs a high-level signal but does not last for the first delay time, it indicates that the voltage at the load access node Rc is less than the first reference voltage Vth1, and thus it can be determined that the load insertion detection circuit still does not meet the detection condition.

[0073] In some other embodiments, the first comparator A1 may also be used to determine whether a load is inserted into the load access node Rc.

[0074] If the load insertion detection circuit meets the detection conditions when the weak pull-up circuit is on, the control circuit maintains the weak pull-up circuit on. If the load insertion detection circuit does not meet the detection conditions when the weak pull-up circuit is on, but the load insertion detection circuit meets the detection conditions when the strong pull-up circuit is on, the control circuit may maintain the strong pull-up circuit on. The output signal of the first comparator A1 is then tested. If the output signal of the first comparator A1 changes from a high-level signal to a low-level signal, it indicates that the voltage of the load access node Rc has been pulled down, indicating that a load is inserted into the load access node Rc.

[0075] It should be noted that the positive input terminal of the first comparator A1 can also be used to access the first reference voltage Vth1, and the negative input terminal of the first comparator A1 can be connected to the load access node Rc. The judgment principle is the same as that in the aforementioned embodiment, except that in this case, when the first comparator A1 outputs a low-level signal and maintains the first delay time, it indicates that the load insertion detection circuit meets the detection condition, and when the output signal of the first comparator A1 changes from a low-level signal to a high-level signal and maintains the second delay time, it can be determined that a load is inserted into the load access node Rc.

[0076] Only one comparator is needed to determine whether the load insertion detection circuit meets the detection conditions and whether a load is inserted into the load access node Rc. This has low cost and simple judgment logic.

[0077] Figure 5 FIG1 shows a circuit diagram of a load insertion detection circuit provided by an embodiment of the present application. Figure 5In some embodiments, the comparison unit 110 further includes a second comparator A2, wherein a non-inverting input terminal of the second comparator A2 is electrically connected to the load access node Rc; and a negative input terminal of the second comparator A2 is configured to receive a second reference voltage, wherein the second reference voltage Vth2 is less than the first reference voltage Vth1. A control circuit is electrically connected to the output terminals of the first comparator A1 and the second comparator A2, respectively. The control circuit is configured to control the corresponding switches to be conductive in descending order of the resistance values of the resistors in the pull-up circuit 120 until the first comparator A1 outputs a high-level signal for a first delay time, maintaining the conductive state of the currently conductive switch. Furthermore, when the signal output by the second comparator A2 changes from a high-level signal to a low-level signal and the low-level signal remains for a second delay time, it is determined that a load is inserted into the load access node.

[0078] After determining that the load insertion detection circuit meets the detection condition through the output signal of the first comparator A1, the second comparator A2 can be enabled to determine whether there is a load inserted into the load access node Rc.

[0079] The non-inverting input terminal of the second comparator A2 is electrically connected to the load access node Rc, and the negative input terminal of the second comparator A2 is connected to the second reference voltage Vth2. When the output signal of the first comparator A1 determines that the load insertion detection circuit meets the detection condition, that is, the voltage at the load access node Rc is greater than the first reference voltage Vth1, since the second reference voltage Vth2 is less than the first reference voltage Vth1, the voltage at the load access node Rc is greater than the second reference voltage Vth2. In other words, when the load insertion detection circuit meets the detection condition, the output signal of the second comparator A2 is also a high-level signal.

[0080] If the output signal of the second comparator A2 changes from a high level signal to a low level signal and the low level signal is maintained for the second delay time, it indicates that the voltage of the load access node Rc is pulled down, ie, a load is connected to the load access node Rc.

[0081] The second reference voltage Vth2 is lower than the first reference voltage Vth1. This means that the reference voltage used to determine whether the load insertion detection circuit meets the detection conditions is higher than the reference voltage used to determine whether a load is inserted. The first reference voltage Vth1 and the second reference voltage Vth2 form a voltage margin range. When the input signal at the load connection node Rc is subject to noise or interference, as long as its fluctuation range remains within the voltage margin, the comparator output will not flip, thereby improving the circuit's anti-interference capability and further enhancing the accuracy of the detection results.

[0082] In some embodiments, the load insertion detection circuit further includes a first switch circuit 131 and a second switch circuit 132, wherein the first end of the first switch circuit 131 is electrically connected to a first reference voltage node, the second end of the first switch circuit 131 is electrically connected to the negative phase input terminal of the first comparator A1, and the first reference voltage node is configured to provide a first reference voltage Vth1; the first end of the second switch circuit 132 is electrically connected to a third reference voltage node, the second end of the second switch circuit 132 is electrically connected to the negative phase input terminal of the first comparator, and the third reference voltage node is configured to provide a third reference voltage Vth3, and the third reference voltage Vth3 is greater than the first reference voltage Vth1.

[0083] The first switch circuit 131 can be switched between an on state and an off state. When the first switch circuit 131 is turned on, the negative input terminal of the first comparator A1 is connected to the first reference voltage Vth1.

[0084] It should be noted that the number of first switch circuits 131 can be determined according to the actual application scenario and is not limited here. For example, the number of first switch circuits 131 can be 1, 2, or 3. The voltage values of the first reference voltage Vth1 connected to the first switch circuits 131 can be the same or different.

[0085] The load insertion detection circuit includes multiple first switch circuits 131, and when the voltage values of the first reference nodes connected to the first switch circuits 131 are the same, when one of the first switch circuits 131 fails, the first switch circuit 131 with the same voltage value as the first reference voltage Vth1 connected to it can be turned on, thereby improving the reliability of the load insertion detection circuit.

[0086] The load insertion detection circuit includes multiple first switch circuits 131, and when the voltage values of the first reference voltage Vth1 connected to the first switch circuit 131 are different, the corresponding first switch circuit 131 can be adaptively turned on when different pull-up circuits 120 are turned on, so that the value of the first reference voltage Vth1 is adjusted according to the turned-on pull-up circuit 120, thereby improving the flexibility of the load insertion detection circuit.

[0087] If the load insertion detection circuit meets the detection condition when the strong pull-up circuit is on, the control circuit can control the second switch circuit 132 to be on and the first switch circuit 131 to be off, thereby connecting the third reference voltage Vth3 to the negative input terminal of the first comparator A1. If the voltage at the load access node Rc is greater than the third reference voltage Vth3, the control circuit can periodically turn off the strong pull-up circuit while controlling the weak pull-up circuit to be on. If the first comparator A1 still detects that the voltage at the load access node Rc is greater than Vth3 and persists after the third delay time, because Vth3 is greater than Vth1, the detection condition is still met when the reference voltage of comparator A1 is switched from Vth3 to Vth1. Therefore, load insertion detection can be performed with the weak pull-up circuit on. If the first comparator A1 detects that the voltage at the load access node Rc does not meet the requirement of "greater than Vth3 and persists for the third delay time", it switches back to the strong pull-up circuit.

[0088] When the weak pull-up circuit is on, the load detection range is wider. The load access node Rc may be connected to the device to be charged via a leakage line. If the device to be charged is unplugged first and then the charging cable, due to leakage in the charging cable, the weak pull-up circuit may cause the load insertion detection circuit to fail to meet the detection conditions. Consequently, the circuit will switch to the strong pull-up circuit. After the charging cable is unplugged, the load insertion detection circuit will remain in the strong pull-up circuit on state. Due to the low resistance of the strong pull-up circuit, the range of load insertion detection will be reduced the next time the detection is made. Therefore, by periodically switching the pull-up circuit 120 from the strong pull-up circuit on state to the weak pull-up circuit on state, the next load insertion detection can be performed with the weak pull-up circuit on state after the charging cable is unplugged. This increases the detection range and compatibility with a wider range of load devices.

[0089] The third reference voltage Vth3 is greater than the first reference voltage Vth1. If the voltage at the load access node Rc is greater than the third reference voltage Vth3, it is also necessarily greater than the first reference voltage Vth1. This ensures that the load insertion detection circuit meets the detection conditions regardless of whether the strong pull-up circuit or the weak pull-up circuit is turned on.

[0090] In other embodiments, the load insertion detection circuit may further include a third switch circuit 133. A first terminal of the third switch circuit 133 is electrically connected to a second reference voltage node, and a second terminal of the third switch circuit 133 is electrically connected to a negative input terminal of the second comparator A2. The second reference voltage node is configured to provide a second reference voltage Vth2. When the third switch circuit 133 is turned on, the negative input terminal of the second comparator A2 is connected to the second reference voltage Vth2. When the second comparator A2 is not operating, the third switch circuit 133 disconnects the second reference voltage Vth2 from the negative input terminal, preventing the reference voltage source from continuously supplying power and reducing power consumption.

[0091] Figure 6 FIG2 is a flow chart showing a control method of a load insertion detection circuit according to an embodiment of the present application. Figure 6 One embodiment of the present application provides a control method for a load insertion detection circuit, which is applied to the aforementioned load insertion detection circuit. The control method includes: step 10 and step 20.

[0092] Step 10: Control the switches in the pull-up circuit 120 to be turned on in descending order of resistance value until the comparison unit 110 outputs the first signal;

[0093] Step 20: Control the currently turned-on switch to maintain the turned-on state and perform load insertion detection.

[0094] The execution subject of the control method of the load insertion detection circuit provided in the embodiment of the present application can be the aforementioned control circuit or a functional module or functional entity in the control circuit that can implement the control method. The control method of the load insertion detection circuit provided in the embodiment of the present application is explained below using the control circuit as an example of the execution subject.

[0095] The following describes the execution steps and principles of the control method proposed in this application, taking the load insertion detection circuit including N pull-up circuits 120 as an example. Assume that the switches in the N pull-up circuits 120 are S1, S2…SN, and the resistance values of the resistors are R1, R2…Rn, respectively. The corresponding pull-up circuits 120 are the first pull-up circuit, the second pull-up circuit 120…the nth pull-up circuit. Among them, R1>R2>…>Rn, that is, the pull-up strength of the pull-up circuit 120 where R1 is located is the weakest, and the pull-up strength of the pull-up circuit 120 where RN is located is the strongest. The pull-up strength gradually increases from R1 to the pull-up circuits 120 where RN is located.

[0096] It should be noted that the comparison unit 110 outputs a first signal, indicating that the voltage of the first input terminal of the comparison unit 110 (load access node Rc) is greater than the first reference voltage Vth1, and the comparison unit 110 outputs a second signal, indicating that the voltage of the first input terminal of the comparison unit 110 (load access node Rc) is less than the first reference voltage Vth1.

[0097] The first input terminal of the comparison unit 110 is connected to the load access node Rc and each pull-up circuit 120, respectively. In the initial state, the control circuit controls the first pull-up circuit to be on for a preset time, while the other pull-up circuits 120 are off, to determine whether the load insertion detection circuit meets the detection conditions. If, within the preset time, the comparison unit 110 outputs a first signal and the first signal is maintained for a first delay time, it indicates that the first pull-up circuit is sufficient to pull the voltage of the load access node Rc to a level greater than the first reference voltage Vth1. Therefore, it can be determined that the load insertion detection circuit meets the detection conditions and load insertion detection is performed. If, within the preset time, the comparison unit 110 always outputs a second signal, or if the comparison unit 110 outputs a first signal but the first signal is maintained for less than the first delay time, it indicates that the first pull-up circuit is insufficient to pull the voltage of the load access node Rc to a level greater than the first reference voltage Vth1. Therefore, it can be determined that the load insertion detection circuit does not meet the detection conditions.

[0098] When the first pull-up circuit is turned on, if the load insertion detection circuit does not meet the detection condition, the control circuit controls the second pull-up circuit 120 to be turned on. If, within a preset time, the comparison unit 110 outputs the first signal and the first signal is maintained for a first delay time, it can be determined that the load insertion detection circuit meets the detection condition and the load insertion detection is performed. If, within a preset time, the comparison unit 110 continuously outputs the second signal, or if the comparison unit 110 outputs the first signal but the first signal is maintained for less than the first delay time, it can be determined that the load insertion detection circuit does not meet the detection condition.

[0099] It should be noted that when the control circuit controls the second pull-up circuit 120 to be turned on, it can control the first pull-up circuit to be turned off, or it can maintain the first pull-up circuit turned on. This is because, regardless of whether the first pull-up circuit is turned on or off, the resistance of the pull-up resistor in the second pull-up circuit 120 after it is turned on is lower than the resistance of the resistor in the first pull-up circuit. The following example uses the example of controlling the previously turned-on pull-up circuit 120 to be turned off when the next pull-up circuit 120 is turned on.

[0100] When the second pull-up circuit 120 is turned on, if the load insertion detection circuit still does not meet the detection condition, the third pull-up circuit 120 is controlled to be turned on, and the above judgment method is repeated, and so on. That is, when the (n-1)th branch is turned on, the load insertion detection circuit does not meet the detection condition, then the nth pull-up circuit 120 is controlled to be turned on until the comparison unit 110 outputs the first signal and the first signal maintains the first delay time, and it is determined that the load insertion detection circuit meets the detection condition, wherein 1 <n≤N。

[0101] A pull-up circuit 120 with a larger resistance value has a wider load insertion detection range, but its pull-up capability is weaker. If a leakage wire is connected to the load access node Rc, the resistance introduced by the leakage wire will form a voltage divider with the weak pull-up circuit. The pull-up circuit 120 with a weak pull-up capability cannot raise the load access node Rc to a voltage greater than the reference voltage, causing the voltage at the load access node Rc to be less than the reference voltage. The comparison unit 110 outputs a second signal, and it can be determined that the load insertion detection circuit does not meet the detection conditions. Therefore, the switch in the pull-up circuit 120 with the largest resistance value is turned on first. When a leakage wire is connected to the load access node Rc and the other end of the leakage wire is connected to a device, the device insertion can still be detected due to the switch to a stronger pull-up.

[0102] It should be noted that the first delay time is a preset time period used to eliminate misjudgments caused by transient changes in the circuit or other interference factors.

[0103] According to the control method of the load insertion detection circuit of the present application, the larger the resistance of the resistor in the pull-up circuit 120, the weaker the pull-up capability. When the load access node Rc is connected to a charging line with leakage, the leakage resistance introduced by the leakage line and the resistance in the pull-up circuit 120 form a voltage divider, so that the voltage of the load access node cannot reach the reference voltage. At this time, the control circuit switches to a pull-up circuit with stronger pull-up capability until the voltage connected to the load access node Rc is higher than the reference voltage, so that when another device is inserted into the leakage charging line, the insertion of the device can be effectively identified; the large-resistance pull-up circuit can cover a wider load insertion detection range, while the small-resistance pull-up circuit can suppress stronger interference, which not only expands the detection range of load access, but also improves anti-interference performance.

[0104] In some embodiments, a currently turned-on switch is controlled to maintain the turned-on state to perform load insertion detection, and the comparison unit is configured to output a second signal when the voltage at the first input terminal is less than the voltage at the second input terminal. The control method includes:

[0105] When the signal output by the comparison unit changes from the first signal to the second signal, it is determined that a load is inserted into the load access node.

[0106] Load insertion detection is performed when the load insertion detection circuit meets the detection conditions, that is, when the voltage at the load access node Rc is higher than the first reference voltage Vth1 and persists for the first delay time. When the output signal of the comparison unit 110 changes from the first signal to the second signal and the second signal persists for the second delay time, it indicates that the voltage at the load access node Rc has been pulled down to below the first reference voltage Vth1, and therefore it can be determined that a load is inserted at the load access node Rc.

[0107] It should be noted that the second delay time is also a preset time period, which is used to eliminate misjudgments caused by transient changes in the circuit or other interference factors.

[0108] In some embodiments, the comparison unit 110 includes a first comparator A1 and a second comparator A2, the positive phase input terminal of the first comparator A1 is electrically connected to the load access node Rc, the negative phase input terminal of the first comparator A1 is used to access the first reference voltage Vth1, the positive phase input terminal of the second comparator A2 is electrically connected to the load access node Rc, the negative phase input terminal of the second comparator A2 is used to access the second reference voltage Vth2, the second reference voltage Vth2 is less than the first reference voltage Vth1, and the control method includes: controlling the switch in the pull-up circuit 120 to be turned on in the order of decreasing resistance until the first comparator A1 outputs a high-level signal and lasts for a first delay time; controlling the currently turned-on switch to maintain the turned-on state, and when the signal output by the second comparator A2 changes from a high-level signal to a low-level signal, and the low-level signal is maintained for a second delay time, it is determined that there is a load inserted into the load access node Rc.

[0109] When the voltage at its positive input terminal (load access node Rc) is greater than the voltage at its negative input terminal (first reference voltage Vth1), first comparator A1 outputs a high-level signal; otherwise, it outputs a low-level signal. By controlling the switches in pull-up circuit 120 to conduct in descending order of resistance, the pull-up capability of pull-up circuit 120 gradually increases until first comparator A1 outputs a high-level signal within the first delay time and for the first delay time, indicating that the voltage at load access node Rc is greater than the first reference voltage Vth1. Consequently, the load insertion detection circuit can be determined to have met the detection conditions.

[0110] After determining that the load insertion detection circuit meets the detection condition through the output signal of the first comparator A1, the second comparator A2 can be enabled to determine whether a load is inserted into the load access node Rc based on the signal output by the second comparator A2.

[0111] The non-inverting input terminal of the second comparator A2 is electrically connected to the load access node Rc, and the negative input terminal of the second comparator A2 is connected to the second reference voltage Vth2. When the output signal of the first comparator A1 determines that the load insertion detection circuit meets the detection condition, that is, the voltage at the load access node Rc is greater than the first reference voltage Vth1 and lasts for the first delay time, since the second reference voltage Vth2 is less than the first reference voltage Vth1, the voltage at the load access node Rc is greater than the second reference voltage Vth2. In other words, when the load insertion detection circuit meets the detection condition, the output signal of the second comparator A2 also becomes a high-level signal.

[0112] If the output signal of the second comparator A2 changes from a high level signal to a low level signal and the low level signal is maintained for the second delay time, it indicates that the voltage of the load access node Rc is pulled down, that is, a load is connected to the load access node Rc.

[0113] The second reference voltage Vth2 is lower than the first reference voltage Vth1. This means that the reference voltage used to determine whether the load insertion detection circuit meets the detection conditions is higher than the reference voltage used to determine whether a load is inserted. The first reference voltage Vth1 and the second reference voltage Vth2 form a voltage margin range. When the input signal at the load connection node Rc is subject to noise or interference, as long as its fluctuation range remains within the voltage margin, the comparator output will not flip, thereby improving the circuit's anti-interference capability and further enhancing the accuracy of the detection results.

[0114] In some embodiments, the switches in the pull-up circuit 120 are controlled to be turned on in descending order of resistance until the first comparator A1 outputs a high-level signal, further comprising: controlling the negative input terminal of the first comparator A1 to be connected to a third reference voltage Vth3, wherein the third reference voltage Vth3 is greater than the first reference voltage Vth1; when the first comparator A1 outputs a high-level signal and the resistance of the resistor in the currently turned-on pull-up circuit 120 is not the maximum resistance, controlling the switch in the currently turned-on pull-up circuit 120 to be turned off according to a preset period, and controlling the switch in the pull-up circuit 120 where the resistor with the largest resistance is located to be turned on; when the first comparator A1 still outputs a high-level signal and maintains the third delay time, controlling the negative input terminal of the first comparator A1 to be connected to the first reference voltage Vth1, and executing the steps of controlling the switches in the pull-up circuit 120 to be turned on in descending order of resistance until the first comparator A1 outputs a high-level signal.

[0115] The load access node Rc may be connected to the device to be charged via a leakage line. If the device to be charged is unplugged first and then the charging line, due to leakage in the charging line, the pull-up capability of the first pull-up circuit to the ath pull-up circuit 120 may not be sufficient to pull the load access node Rc to a voltage greater than the first reference voltage Vth1, and the nth (n greater than a) pull-up circuit 120 will be switched on until the load insertion detection circuit meets the detection conditions. If the charging line is then unplugged, the load insertion detection circuit will remain in the nth pull-up circuit on state, and the range for identifying the next resistive load insertion will be narrowed. To expand the resistive load identification range in this case, after determining that the load insertion detection circuit meets the detection conditions, the control circuit can switch the conductive pull-up circuit 120 from the nth pull-up circuit back to the first pull-up circuit while performing load insertion detection using the second comparator A2.

[0116] Specifically, when the nth pull-up circuit is turned on and the load insertion detection circuit meets the detection conditions, the control circuit controls the negative input of the first comparator A1 to connect to the third reference voltage Vth3, and controls the nth pull-up circuit to turn off according to a preset period, while simultaneously turning on the first pull-up circuit. If the load insertion detection circuit still meets the detection conditions in this situation, indicating that the charging cable connected to the load access node Rc has been unplugged, the load insertion detection can be performed with the first pull-up circuit turned on, expanding the resistance range for the next load insertion detection. Because the third reference voltage Vth3 is greater than the first reference voltage Vth1, if the voltage at the load access node Rc is greater than the third reference voltage Vth3, it must also be greater than the first reference voltage Vth1. Therefore, setting the third reference voltage Vth3 greater than the first reference voltage Vth1 ensures that the load insertion detection circuit meets the detection conditions regardless of whether the turned-on pull-up circuit 120 is the first pull-up circuit or the nth pull-up circuit.

[0117] The aforementioned load insertion detection circuit still meets the detection condition in this situation. This means that during the third delay period after controlling the nth pull-up circuit to be turned off and the first pull-up circuit to be turned on, the output signal of the first comparator A1 remains high. In other words, the voltage at the load access node Rc remains greater than the third reference voltage Vth3 during the third delay period. The control circuit then controls the negative input terminal of the first comparator A1 to be connected to the first reference voltage Vth1, and the voltage at the load access node Rc remains greater than the first reference voltage Vth during the first delay period. To ensure the integrity of the detection period, the third delay period is shorter than the duration of the preset period.

[0118] It should be noted that the specific duration of the third delay time and the preset period can be determined according to the actual application scenario and is not limited here. For example, the third delay time can be 5ms or 8ms. The specific duration of the preset period can be 10s or 20s.

[0119] In some embodiments, when the first comparator A1 outputs a high-level signal and the resistance of the resistor in the currently turned-on pull-up circuit 120 is not the maximum resistance, after controlling the switch in the currently turned-on pull-up circuit 120 to be disconnected according to a preset period and controlling the switch in the pull-up circuit 120 where the resistor with the largest resistance is located to be turned on, the method further includes: when the output signal of the first comparator A1 changes from a high-level signal to a low-level signal within a third delay time, controlling the switch in the pull-up circuit 120 where the resistor with the largest resistance is located to be disconnected, and controlling the switch in the previously disconnected pull-up circuit 120 to be turned on.

[0120] When the control circuit controls the pull-up circuit 120 to be turned on according to a preset period, switching from the nth pull-up circuit to the first pull-up circuit, if the output signal changes from the first signal to the second signal within the third delay time, it means that the first pull-up circuit is insufficient to pull up the voltage of the load access node Rc to a level greater than the third reference voltage Vth3, that is, a charging cable or a charging device is still plugged into the load access node Rc. In this case, the nth pull-up circuit is controlled to be turned on, and the comparison between the voltage of the load access node Rc and the third reference voltage Vth3 is performed again to avoid inaccurate detection results caused by forcibly switching the pull-up circuit 120 to be turned on.

[0121] In some embodiments, the control method further includes: after the switch in the pull-up circuit 120 with the smallest resistance value is turned on, when the output signal of the comparison unit 110 is still a low-level signal, controlling the switch on the pull-up circuit 120 with the largest resistance value to be turned on, and controlling the switches on the remaining pull-up circuits 120 to be turned off.

[0122] When the switch in the pull-up circuit 120 with the smallest resistance value is turned on, meaning that the pull-up circuit 120 with the strongest pull-up capability is in the on state, if the comparison unit 110 outputs the second signal at this time, this indicates that a short circuit or other fault may have occurred at the load access node Rc. The control circuit then turns on the first pull-up circuit and waits for the first comparator A1 to output the first signal for a first delay time, determining that the load insertion detection circuit meets the detection condition. Because the first pull-up circuit has the largest resistance value, the current in the load insertion detection circuit is minimized, thereby saving power.

[0123] One embodiment of the present application provides a multi-port charger, comprising a plurality of USB ports and a plurality of the aforementioned load insertion detection circuits, wherein a load access node Rc of each load insertion detection circuit is electrically connected to a corresponding USB port.

[0124] The load insertion detection circuit is used to detect whether a load is plugged into the USB port. The specific structure and working principle of the load insertion detection circuit can be referred to the above embodiment and will not be described in detail here.

[0125] According to the multi-port charger of the present application, the larger the resistance of the resistor in the pull-up circuit 120, the weaker the pull-up capability. When the load access node Rc is connected to a charging line with leakage, the leakage resistance introduced by the leakage line will form a voltage divider with the resistor in the pull-up circuit 120, so that the voltage of the load access node cannot reach the reference voltage. At this time, the control circuit switches to a pull-up circuit with stronger pull-up capability until the voltage connected to the load access node Rc is higher than the reference voltage, so that when another device is inserted into the leaking charging line, the insertion of the device can be effectively identified; the large-resistance pull-up circuit can cover a wider load insertion detection range, while the small-resistance pull-up circuit can suppress stronger interference, which not only expands the detection range of load access, but also improves anti-interference performance.

[0126] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A load insertion detection circuit, characterized in that: include: a comparison unit, wherein a first input terminal of the comparison unit is connected to the load access node, a second input terminal of the comparison unit is used to access a reference voltage, and the comparison unit is configured to output a first signal when the voltage at the first input terminal is greater than the voltage at the second input terminal; a plurality of pull-up circuits, each comprising a switch and a resistor connected in series, a first end of each pull-up circuit being electrically connected to the same supply voltage node, a second end of each pull-up circuit being electrically connected to the load access node, and a resistance value of each resistor in each pull-up circuit being different; A control circuit is electrically connected to the driving end of each switch and the output end of the comparison unit, respectively. The control circuit is configured to control the corresponding switches to be turned on in the order of decreasing resistance values of the resistors in the pull-up circuit until the comparison unit outputs a first signal, and maintain the on state of the currently turned-on switches to perform load insertion detection.

2. The load insertion detection circuit according to claim 1, wherein: The comparison unit includes: a first comparator, wherein a positive input terminal of the first comparator is connected to the load access node, and a negative input terminal of the first comparator is used to access a first reference voltage; a second comparator, wherein a positive input terminal of the second comparator is connected to the load access node, and a negative input terminal of the second comparator is used to access a second reference voltage, wherein the second reference voltage is less than the first reference voltage; The control circuit is electrically connected to the output end of the first comparator and the output end of the second comparator, respectively. The control circuit is configured to control the corresponding switches to be turned on in the order of decreasing resistance values of the resistors in the pull-up circuit until the first comparator outputs a high-level signal and maintains the on state of the currently turned-on switch. When the signal output by the second comparator changes from a high-level signal to a low-level signal, it is determined that a load is inserted into the load access node.

3. The load insertion detection circuit according to claim 2, wherein: The load insertion detection circuit further includes: a first switch circuit, wherein a first terminal of the first switch circuit is electrically connected to a first reference voltage node, a second terminal of the first switch circuit is electrically connected to a negative input terminal of the first comparator, and the first reference voltage node is configured to provide the first reference voltage; A second switching circuit, wherein a first end of the second switching circuit is electrically connected to a third reference voltage node, a second end of the third switching circuit is electrically connected to a negative input terminal of the first comparator, and the third reference voltage node is configured to provide a third reference voltage, and the third reference voltage is greater than the first reference voltage.

4. A control method for a load insertion detection circuit, characterized in that: Applied to the load insertion detection circuit according to any one of claims 1 to 3, the control method includes: Controlling the switch in the pull-up circuit to be turned on in descending order of resistance value until the comparison unit outputs a first signal; The switch that is currently turned on is controlled to maintain the on state, and load insertion detection is performed.

5. The control method of the load insertion detection circuit according to claim 4, characterized in that: The switch currently turned on is controlled to maintain the turned-on state to perform load insertion detection, and the comparison unit is configured to output a second signal when the voltage at the first input terminal is less than the voltage at the second input terminal. The control method includes: When the signal output by the comparison unit changes from the first signal to the second signal, it is determined that a load is inserted into the load access node.

6. The control method of the load insertion detection circuit according to claim 5, characterized in that: The comparison unit includes a first comparator and a second comparator, wherein a positive phase input terminal of the first comparator is electrically connected to a load access node, and a negative phase input terminal of the first comparator is used to access a first reference voltage, a positive phase input terminal of the second comparator is electrically connected to the load access node, and a negative phase input terminal of the second comparator is used to access a second reference voltage, wherein the second reference voltage is less than the first reference voltage, and the control method includes: Controlling the switch in the pull-up circuit to be turned on in descending order of resistance value until the first comparator outputs a high level signal; The switch currently turned on is controlled to maintain the turned-on state, and when the signal output by the second comparator changes from a high-level signal to a low-level signal, it is determined that a load is inserted into the load access node.

7. The control method of the load insertion detection circuit according to claim 6, characterized in that: The method further comprises: controlling the switches in the pull-up circuit to be turned on in the order of decreasing resistance values until the first comparator outputs a high level signal; Controlling the negative input terminal of the first comparator to be connected to a third reference voltage, wherein the third reference voltage is greater than the first reference voltage; When the first comparator outputs a high-level signal and the resistance of the resistor in the currently turned-on pull-up circuit is not the maximum resistance, controlling the switch in the currently turned-on pull-up circuit to be turned off according to a preset period, and controlling the switch in the pull-up circuit where the resistor with the largest resistance is located to be turned on; When the first comparator still outputs a high-level signal, the negative input terminal of the first comparator is controlled to be connected to the first reference voltage, and the step of controlling the switch in the pull-up circuit to be turned on in the order of decreasing resistance values is performed until the first comparator outputs a high-level signal.

8. The control method of the load insertion detection circuit according to claim 7, characterized in that: After controlling the switch in the currently turned-on pull-up circuit to be turned off according to a preset period and controlling the switch in the pull-up circuit where the resistor with the largest resistance is located to be turned on when the first comparator outputs a high-level signal and the resistance value of the resistor in the currently turned-on pull-up circuit is not the maximum resistance value, the method further includes: When the output signal of the first comparator changes from a high-level signal to a low-level signal, the switch in the pull-up circuit where the resistor with the largest resistance is located is controlled to be disconnected, and the switch in the pull-up circuit that was previously disconnected is controlled to be turned on.

9. The control method of the load insertion detection circuit according to any one of claims 4 to 8, further comprising: After the switch in the pull-up circuit with the smallest resistance value is turned on, if the comparison unit output signal is still a low level signal, the switch in the pull-up circuit with the largest resistance value is controlled to be turned on, and the switches in the remaining pull-up circuits are controlled to be turned off.

10. A multi-port charger, characterized in that: The device comprises a plurality of USB ports and a plurality of load insertion detection circuits according to any one of claims 1 to 3, wherein a load access node of each load insertion detection circuit is electrically connected to a corresponding USB port.

Images