Circuit for measuring current through external interface of product and terminal equipment

Abstract

The invention relates to a circuit for measuring current through an external interface of a product and terminal equipment, the circuit comprises an interface circuit and a power switch circuit, the interface circuit comprises a control unit J1, a DN1 signal pin and a DN2 signal pin in the control unit J1 are connected with a BATTL level in the power switch circuit, and the DN1 signal pin and the DN2 signal pin in the control unit J1 are connected with the BATTL level in the power switch circuit. And a DP1 signal pin and a DP2 signal pin in the control unit J1 are connected with a BATT level in the power switch circuit. The power switch circuit comprises a triode Q4 and a triode Q5, an emitting electrode in the triode Q4 is connected with a BATTL level in the power switch circuit, a base electrode in the triode Q4 is connected with a collecting electrode in the triode Q5 through a resistor R8, a collecting electrode in the triode Q4 is connected with a BATT level in the power switch circuit, the collecting electrode in the triode Q5 is further connected with an EN signal port through a resistor R20, and the EN signal port is connected with the power switch circuit. The EN signal port is grounded through a resistor R17 and a resistor R18, a base electrode in the triode Q5 is connected between the resistor R17 and the resistor R18 in parallel, and an emitting electrode in the triode Q5 is grounded.

Description

Technical Field

[0001] The present application relates to the field of current detection, and in particular to a circuit and terminal device for measuring current through an external interface of a product. Background Art

[0002] In modern electronic devices, accurate measurement of current is essential to ensure stable operation and safety of the equipment. Traditional current measurement methods often rely on complex circuit design and expensive dedicated instruments, which not only increases the cost but also limits its application scope. With the development of technology, the demand for direct current measurement through the external interface of the product is growing, especially in portable devices and battery-powered applications.

[0003] Although the existing current measurement technology has met the needs to a certain extent, it still has some shortcomings, such as high circuit complexity, high cost, and limited measurement accuracy. Especially when current measurement needs to be performed through the external interface of the product, the existing technical solutions often find it difficult to balance simplicity, cost-effectiveness, and measurement performance. In addition, as electronic devices develop towards miniaturization and integration, higher requirements are also placed on the volume and power consumption of current measurement circuits.

[0004] Therefore, in view of the above-mentioned shortcomings, the present invention provides a new solution. Summary of the invention

[0005] The main purpose of the present application is to provide a circuit and terminal device for measuring current through an external interface of a product, which can utilize a combination of an interface circuit and a power switch circuit to realize the function of directly measuring current through an external interface of a product.

[0006] To achieve the above-mentioned purpose, the present application provides a circuit for measuring current through an external interface of a product, including: an interface circuit and a power switch circuit, the interface circuit including: a control unit J1, the DN1 signal pin and the DN2 signal pin in the control unit J1 are connected to the BATTL level in the power switch circuit, and the DP1 signal pin and the DP2 signal pin in the control unit J1 are connected to the BATT level in the power switch circuit.

[0007] The power switch circuit includes: a transistor Q4 and a transistor Q5, the emitter of the transistor Q4 is connected to the BATTL level in the power switch circuit, the base of the transistor Q4 is connected to the collector of the transistor Q5 through a resistor R8, and a resistor R13 is connected in parallel between the emitter and the base of the transistor Q4, the collector of the transistor Q4 is connected to the BATT level in the power switch circuit, the collector of the transistor Q5 is also connected to the EN signal port through a resistor R20, the EN signal port is grounded through a resistor R17 and a resistor R18, the base of the transistor Q5 is connected in parallel between the resistor R17 and the resistor R18, and the emitter of the transistor Q5 is grounded.

[0008] Preferably, the power switch circuit further comprises: a MOS tube Q3, wherein the drain of the MOS tube Q3 is connected to the BATT level, the source of the MOS tube Q3 is connected to the BATTL level, the gate of the MOS tube Q3 is connected to the collector of the transistor Q4, and is grounded through a resistor R9.

[0009] Preferably, the resistor R10 is NC / 0R.

[0010] Preferably, the BATT level is grounded via capacitor C68, and the BATTL level is grounded via capacitor C67.

[0011] Preferably, the interface circuit further comprises: USB 5V, which is connected to the VBUS signal pin in the control unit J1 and is grounded through a capacitor C5.

[0012] Preferably, the interface circuit further comprises: a diode Z1, wherein the cathode of the diode Z1 is connected to the USB 5V, and the anode of the diode Z1 is grounded.

[0013] Preferably, the CC1 signal pin in the control unit J1 is grounded via a resistor R21, and the CC2 signal pin in the control unit J1 is grounded via a resistor R15.

[0014] In addition, a terminal device is also provided, which is provided with the above-mentioned circuit for measuring current through the external interface of the product.

[0015] The beneficial effects of the technical solution of the present invention are:

[0016] When the DN1 and DN2 signal pins of the control unit J1 output a high level, the base of the transistor Q4 receives a high level signal, causing the transistor Q4 to turn on. Since the emitter of the transistor Q4 is connected to the BATTL level and the collector is connected to the BATT level, when the transistor Q4 is turned on, a path is formed between the BATTL level and the BATT level, allowing current to flow, and the base of the transistor Q5 is grounded through resistors R17 and R18, while the collector is connected to the EN signal port through resistor R20. When the transistor Q4 is turned on, its collector voltage drops, causing the base voltage of the transistor Q5 to drop as well, thereby turning on the transistor Q5. The conduction of the transistor Q5 further strengthens the path between the BATTL level and the BATT level, making the current measurement more stable.

[0017] At the same time, resistors R8 and R13 are respectively connected between the base and emitter of transistor Q4, and between the collector of transistor Q5 and the signal pin of control unit J1, to limit the current and protect the circuit from damage caused by excessive current. Furthermore, when current flows through the BATTL level and BATT level, a certain voltage drop will be generated at the EN signal port, and the voltage change in the circuit is monitored by the EN signal port connected to the ground by resistors R17 and R18, so as to understand the change of current in real time. If the current exceeds the preset safety range, corresponding measures can be taken by the control unit J1, such as cutting off the power supply or sounding an alarm, to protect the safety of the circuit and equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a USB interface circuit provided in accordance with an embodiment of the present application.

[0019] Figure 2 A schematic diagram of a power switch circuit provided in accordance with an embodiment of the present application.

[0020] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0021] The embodiments of the present application are described in detail below, and 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 intended to be used to explain the present application, and should not be construed as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0022] In addition, if the description of "first", "second", etc. is involved in this application, it is only used for descriptive purposes (such as for distinguishing the same or similar elements), and cannot be understood as indicating or suggesting its relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0023] See also Figure 1-Figure 2 The present invention proposes a circuit for measuring current through an external interface of a product, including: an interface circuit and a power switch circuit, wherein the interface circuit includes: a control unit J1, wherein a DN1 signal pin and a DN2 signal pin in the control unit J1 are connected to a BATTL level in the power switch circuit, and a DP1 signal pin and a DP2 signal pin in the control unit J1 are connected to a BATT level in the power switch circuit;

[0024] The power switch circuit includes: a transistor Q4 and a transistor Q5, the emitter of the transistor Q4 is connected to the BATTL level in the power switch circuit, the base of the transistor Q4 is connected to the collector of the transistor Q5 through a resistor R8, and a resistor R13 is connected in parallel between the emitter and the base of the transistor Q4, the collector of the transistor Q4 is connected to the BATT level in the power switch circuit, the collector of the transistor Q5 is also connected to the EN signal port through a resistor R20, the EN signal port is grounded through a resistor R17 and a resistor R18, the base of the transistor Q5 is connected in parallel between the resistor R17 and the resistor R18, and the emitter of the transistor Q5 is grounded.

[0025] In this solution, the control of the BATTL level and BATT level in the power switch circuit is realized through the DN1 and DN2 signal pins and the DP1 and DP2 signal pins of the control unit J1. When the control unit J1 outputs a high level, transistors Q4 and Q5 are turned on, so that a path is formed between the BATTL level and the BATT level, thereby realizing the measurement of the current. At the same time, by adjusting the resistance values ​​of resistors R8, R13, R20, R17 and R18, the conduction degree of transistors Q4 and Q5 is changed, thereby adjusting the current. And by monitoring the voltage change of the EN signal port, the change of the current can be understood in real time, so as to carry out corresponding control and protection.

[0026] Specifically, when the DN1 and DN2 signal pins of the control unit J1 output a high level, the base of the transistor Q4 receives a high level signal, causing the transistor Q4 to be turned on. Since the emitter of the transistor Q4 is connected to the BATTL level and the collector is connected to the BATT level, when the transistor Q4 is turned on, a path is formed between the BATTL level and the BATT level, allowing current to flow, and the base of the transistor Q5 is grounded through resistors R17 and R18, while the collector is connected to the EN signal port through resistor R20. When the transistor Q4 is turned on, its collector voltage drops, causing the base voltage of the transistor Q5 to drop as well, thereby turning on the transistor Q5. The conduction of the transistor Q5 further strengthens the path between the BATTL level and the BATT level, making the current measurement more stable.

[0027] At the same time, resistors R8 and R13 are respectively connected between the base and emitter of transistor Q4, and between the collector of transistor Q5 and the signal pin of control unit J1, to limit the current and protect the circuit from damage caused by excessive current. Furthermore, when current flows through the BATTL level and BATT level, a certain voltage drop will be generated at the EN signal port, and the voltage change in the circuit is monitored by the EN signal port connected to the ground by resistors R17 and R18, so as to understand the change of current in real time. If the current exceeds the preset safety range, corresponding measures can be taken by the control unit J1, such as cutting off the power supply or sounding an alarm, to protect the safety of the circuit and equipment.

[0028] In one embodiment, the power switch circuit further includes: a MOS tube Q3, wherein the drain of the MOS tube Q3 is connected to the BATT level, the source of the MOS tube Q3 is connected to the BATTL level, the gate of the MOS tube Q3 is connected to the collector of the transistor Q4, and is grounded through a resistor R9.

[0029] In this solution, the control capability and stability of the circuit are further enhanced by introducing the MOS tube Q3.

[0030] Specifically, the gate of the MOS transistor Q3 is connected to the collector of the transistor Q4 and grounded through the resistor R9, so that the conduction state of the MOS transistor Q3 is directly controlled by the collector voltage of the transistor Q4.

[0031] In one embodiment, the resistor R10 is NC / 0R.

[0032] By setting the resistor R10 to NC (Not Connected) or 0Ω (ohm), flexible adjustment and optimization of the circuit can be achieved.

[0033] Specifically, when the resistor R10 is set to NC, it means that no resistor is connected to this position, so that the circuit part related to this resistor can be disconnected, which is convenient for troubleshooting or circuit modification. When the resistor R10 is set to 0Ω, it is equivalent to connecting a wire to this position, which can effectively short-circuit the two nodes, thereby changing the working state of the circuit or achieving specific functional requirements.

[0034] In one embodiment, the BATT level is grounded through a capacitor C68, and the BATTL level is grounded through a capacitor C67.

[0035] In this solution, the BATT level and the BATTL level are grounded through capacitors C68 and C67 respectively, so that high-frequency noise on the power line is effectively filtered out and the accuracy of current measurement is improved.

[0036] In one embodiment, the interface circuit further includes: USB 5V, wherein the USB 5V is connected to the VBUS signal pin in the control unit J1 and is grounded through a capacitor C5.

[0037] In this solution, by introducing the USB 5V power supply, a stable voltage supply can be provided to ensure that the control unit J1 can work normally.

[0038] Specifically, when the USB interface is plugged into a computer or other USB host device, the USB 5V power supply is provided to the control unit J1 through the VBUS signal pin. Capacitor C5 is connected in parallel between the VBUS signal pin and the ground to play a role in decoupling and filtering, reducing power supply noise and interference, and improving the stability and reliability of the power supply.

[0039] In one embodiment, the interface circuit further includes: a diode Z1, wherein a cathode of the diode Z1 is connected to the USB 5V, and an anode of the diode Z1 is grounded.

[0040] In this solution, by introducing diode Z1, reverse voltage protection can be provided to prevent device damage caused by reverse power connection. When USB 5V is correctly connected, diode Z1 is in the cut-off state and will not affect the normal operation of the circuit. However, if USB 5V is mistakenly connected to a negative voltage, diode Z1 will be turned on and direct the current to the ground line, thereby preventing the control unit J1 and other sensitive components from being damaged by reverse voltage.

[0041] Specifically, when the USB 5V power supply is correctly connected, that is, the USB 5V is a positive voltage, the cathode of the diode Z1 is a high level, and the anode is a low level. At this time, the diode Z1 is in a reverse biased state and will not conduct. However, if the USB 5V is mistakenly connected to a negative voltage, that is, the USB 5V is a negative voltage, the cathode of the diode Z1 becomes a low level, and the anode becomes a high level. At this time, the diode Z1 is in a forward biased state and will conduct. In this way, any current that may be caused by the reverse voltage will flow to the ground through the diode Z1, thereby protecting the entire circuit.

[0042] In one embodiment, the CC1 signal pin in the control unit J1 is grounded through a resistor R21, and the CC2 signal pin in the control unit J1 is grounded through a resistor R15.

[0043] In this solution, the current detection function of the circuit can be realized by grounding the CC1 and CC2 signal pins through resistors R21 and R15 respectively.

[0044] In one embodiment, resistor R15=5.1K, resistor R21=5.1K, resistor R17=10M, resistor R18=10M, capacitor C68=0.1uF, capacitor C67=0.1uF, capacitor C5=0.1uF.

[0045] In addition, a terminal device is also provided, which is provided with the above-mentioned circuit for measuring current through the external interface of the product.

[0046] It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, device, article or method for improving the efficiency of sql table join calculations that includes a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, device, article or method for improving the efficiency of sql table join calculations. In the absence of more restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, device, article or method for improving the efficiency of sql table join calculations that includes the element.

[0047] The above description is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A circuit for measuring current through an external interface of a product, characterized in that: include: An interface circuit and a power switch circuit, the interface circuit comprising: a control unit J1, a DN1 signal pin and a DN2 signal pin in the control unit J1 connected to a BATTL level in the power switch circuit, and a DP1 signal pin and a DP2 signal pin in the control unit J1 connected to a BATT level in the power switch circuit; The power switch circuit includes: a transistor Q4 and a transistor Q5, the emitter of the transistor Q4 is connected to the BATTL level in the power switch circuit, the base of the transistor Q4 is connected to the collector of the transistor Q5 through a resistor R8, and a resistor R13 is connected in parallel between the emitter and the base of the transistor Q4, the collector of the transistor Q4 is connected to the BATT level in the power switch circuit, the collector of the transistor Q5 is also connected to the EN signal port through a resistor R20, the EN signal port is grounded through a resistor R17 and a resistor R18, the base of the transistor Q5 is connected in parallel between the resistor R17 and the resistor R18, and the emitter of the transistor Q5 is grounded.

2. A circuit for measuring current through an external interface of a product according to claim 1, characterized in that: The power switch circuit further includes: a MOS tube Q3, wherein the drain of the MOS tube Q3 is connected to the BATT level, the source of the MOS tube Q3 is connected to the BATTL level, the gate of the MOS tube Q3 is connected to the collector of the triode Q4, and is grounded through a resistor R9.

3. A circuit for measuring current through an external interface of a product according to claim 2, characterized in that: The resistor R10 is NC / 0R.

4. A circuit for measuring current through an external interface of a product according to claim 3, characterized in that: The BATT level is grounded through capacitor C68, and the BATTL level is grounded through capacitor C67.

5. A circuit for measuring current through a product external interface according to claim 1, characterized in that: The interface circuit further includes: a USB 5V, wherein the USB 5V is connected to a VBUS signal pin in the control unit J1 and is grounded via a capacitor C5.

6. A circuit for measuring current through an external interface of a product according to claim 5, characterized in that: The interface circuit further includes: a diode Z1, wherein the cathode of the diode Z1 is connected to the USB 5V, and the anode of the diode Z1 is grounded.

7. A circuit for measuring current through an external interface of a product according to claim 6, characterized in that: The CC1 signal pin in the control unit J1 is grounded through a resistor R21, and the CC2 signal pin in the control unit J1 is grounded through a resistor R15.

8. A terminal device, characterized in that: A circuit for measuring current through an external interface of a product according to any one of claims 1 to 7 is provided.

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