Liquid inlet detection circuit and electronic device

Abstract

The present disclosure provides a liquid inlet detection circuit and an electronic device. The liquid inlet detection circuit comprises a detection end, an excitation source, an amplification circuit, a first capacitor and a controller. The detection end is configured to be connected to a to-be-tested pin of a connector. The excitation source is configured to output a square wave signal. The amplification circuit comprises a first input end and a second input end, and the excitation source is connected to the first input end. The first capacitor is connected between the second input end and the detection end. The controller comprises a voltage detection port connected to an output end of the amplification circuit, configured to detect a voltage output by the output end of the amplification circuit and determine the impedance of the to-be-tested pin. In this way, the amplification circuit can be protected, and the safety is high.

Description

Technical Field

[0001] This disclosure relates to the field of detection technology, and in particular to a liquid ingress detection circuit and electronic device. Background Technology

[0002] Electronic devices include connectors, which enable functions such as charging and data transmission. During use, connectors may come into contact with liquids, creating a potential difference between adjacent pins and causing electro-corrosion, potentially leading to charging interruptions. A liquid ingress detection circuit can determine if liquid has entered the pin being tested. However, some liquid ingress detection circuits connect the tested pin directly to the input of an amplifier circuit. This means that if a high DC voltage is present at the tested pin, the amplifier circuit can be damaged, resulting in low safety. Utility Model Content

[0003] This disclosure provides a liquid ingress detection circuit and electronic device that can protect the amplifier circuit and has high safety.

[0004] This disclosure provides a liquid ingress detection circuit, including: The detection end is used to connect to the pin being tested on the connector; Excitation source, used to output square wave signal; An amplifier circuit includes a first input terminal and a second input terminal, wherein the excitation source is connected to the first input terminal; A first capacitor is connected between the second input terminal and the detection terminal; and The controller includes a voltage detection port connected to the output terminal of the amplifier circuit, used to detect the voltage output by the output terminal of the amplifier circuit and determine the impedance of the pin under test.

[0005] Furthermore, it also includes a peak sampling circuit, which is connected between the output of the amplifier circuit and the voltage detection port. The controller is used to detect the voltage output by the peak sampling circuit and determine the impedance of the pin under test.

[0006] Furthermore, it also includes a ground terminal; the peak sampling circuit includes a sampling diode and a sampling capacitor; the anode of the sampling diode is connected to the output terminal of the amplifier circuit, and the cathode of the sampling diode is connected between the voltage detection port and the first terminal of the sampling capacitor; the second terminal of the sampling capacitor is connected to the ground terminal.

[0007] Furthermore, the peak sampling circuit also includes a first operational amplifier, the amplifier circuit being connected to the non-inverting input of the first operational amplifier, the inverting input of the first operational amplifier being connected to the voltage detection port, and the output of the first operational amplifier being connected to the anode of the sampling diode.

[0008] Furthermore, the peak sampling circuit also includes a pull-down resistor connected between the voltage detection port and the ground terminal.

[0009] Furthermore, the amplification circuit includes a second operational amplifier, the excitation source is connected to the non-inverting input terminal of the second operational amplifier, the first capacitor is connected between the inverting input terminal of the second operational amplifier and the detection terminal; the voltage detection port is connected to the output terminal of the second operational amplifier.

[0010] Furthermore, the amplification circuit further includes a first resistor connected between the excitation source and the non-inverting input of the second operational amplifier; and / or The amplifier circuit also includes a second resistor connected between the detection terminal and the inverting input terminal of the second operational amplifier.

[0011] Furthermore, the amplifier circuit also includes a third resistor, the first end of which is connected between the first capacitor and the inverting input terminal of the second operational amplifier; the second end of which is connected between the output terminal of the second operational amplifier and the voltage detection port.

[0012] Furthermore, the amplifier circuit also includes a second capacitor connected in parallel with the second operational amplifier. The first end of the second capacitor is connected between the first capacitor and the inverting input terminal of the second operational amplifier; the second end of the second capacitor is connected between the output terminal of the second operational amplifier and the voltage detection port.

[0013] This disclosure provides an electronic device, including a connector and a liquid ingress detection circuit as described in any of the above embodiments, the connector including a pin to be tested.

[0014] The liquid ingress detection circuit provided in this disclosure includes a first capacitor connected between the second input terminal of the amplifier circuit and the detection terminal for connection with the test pin of the connector. The first capacitor can isolate the DC bias signal of the test pin, so that when there is a high DC voltage on the test pin, it can protect subsequent circuits such as the amplifier circuit, thus ensuring high safety.

[0015] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0017] Figure 1 The diagram shown is a simplified structural diagram of an electronic device provided in one embodiment of this disclosure; Figure 2 The diagram shown is a circuit block diagram of a liquid inlet detection circuit provided in one embodiment of this disclosure; Figure 3 As shown Figure 2 Circuit diagram of the liquid ingress detection circuit. Detailed Implementation

[0018] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0019] To better understand the technical solutions of this disclosure, the liquid ingress detection circuit and electronic equipment of this disclosure will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the features in the following embodiments and implementations can be combined with each other.

[0020] Figure 1 The diagram shown is a simplified structural diagram of an electronic device 10 provided in one embodiment of this disclosure. This disclosure provides an electronic device 10, which includes a connector 11 and a liquid ingress detection circuit 12. The electronic device can be, for example, a mobile phone, a tablet computer, or other device equipped with a connector. The connector 11 can be a Type-C, Type-D, or other port. The connector 11 includes a pin 13 to be tested. Liquid ingress detection of the pin 13 can be achieved through the liquid ingress detection circuit 12.

[0021] Figure 2 The diagram shown is a circuit block diagram of a liquid inlet detection circuit 12 provided in one embodiment of this disclosure. See also... Figure 2 As shown, this disclosure provides a liquid ingress detection circuit 12, which includes a detection terminal 14, an excitation source 15, an amplifier circuit 16, a first capacitor C1, and a controller 17.

[0022] The detection terminal 14 is used to connect to the tested pin 13 of the connector 11. The excitation source 15 is used to output a square wave signal. The excitation source 15 can be an AC source used to output a square wave signal of a set frequency.

[0023] The amplifier circuit 16 includes a first input terminal 18 and a second input terminal 19. The excitation source 15 is connected to the first input terminal 18 and applies a square wave signal to the amplifier circuit 16 through the first input / output terminal 18. The first capacitor C1 is connected between the second input terminal 19 and the detection terminal 14.

[0024] The controller 17 includes a voltage detection port 20, which is connected to the output terminal 21 of the amplifier circuit 16. The voltage detection port 20 is used to detect the voltage output from the output terminal 21 of the amplifier circuit 16 and determine the magnitude of the impedance Rx of the measured pin 13. The impedance Rx of the measured pin 13 (e.g., ...) can be used to determine the voltage. Figure 3 The value of the impedance Rx of the tested pin 13 (as shown) is used to determine whether liquid has entered the tested pin 13. If the impedance Rx of the tested pin 13 is less than the set value, then liquid has entered the tested pin 13.

[0025] The liquid ingress detection circuit 12 provided in this disclosure includes a first capacitor C1. The first capacitor C1 is connected between the second input terminal 19 of the amplifier circuit 16 and the detection terminal 14 for connection to the tested pin 13 of the connector 11. The first capacitor C1 can isolate the DC bias signal of the tested pin 13. Thus, when there is a high DC voltage on the tested pin 13, it can protect subsequent circuits such as the amplifier circuit 16, thereby ensuring high safety. At the same time, by using only the first capacitor C1, the overvoltage protection circuit can be eliminated, resulting in a simple structure and cost savings.

[0026] Figure 3 As shown Figure 2 Circuit diagram of liquid ingress detection circuit 12. See also... Figure 3 As shown, in one embodiment, the liquid ingress detection circuit 12 further includes a peak sampling circuit 22. The peak sampling circuit 22 is connected between the output terminal 21 of the amplifier circuit 16 and the voltage detection port 20. The controller 17 is used to detect the voltage output by the peak sampling circuit 22 and determine the impedance Rx of the measured pin 13. The signal output by the output terminal 21 of the amplifier circuit 16 is a square wave voltage signal with DC bias. The peak sampling circuit 22 is connected between the output terminal 21 of the amplifier circuit 16 and the voltage detection port 20. The square wave voltage signal with DC bias can pass through the peak sampling circuit 22 and output a DC voltage signal. The controller 17 detects the voltage of the DC voltage signal output by the peak sampling circuit 22. The peak-to-peak value of the square wave voltage signal with DC bias can be characterized by the DC voltage signal output by the peak sampling circuit 22, thus making the detection more accurate. Moreover, there is no need to add an external high-speed ADC (Analog-to-Digital Converter) to collect the peak-to-peak value of the signal in real time, thus saving costs.

[0027] In one embodiment, the liquid ingress detection circuit 12 further includes a ground terminal GND. The peak sampling circuit 22 includes a sampling diode D1 and a sampling capacitor C2. The anode of the sampling diode D1 is connected to the output terminal 21 of the amplifier circuit 16, the cathode of the sampling diode D1 is connected between the voltage detection port 20 and the first terminal of the sampling capacitor C2, and the second terminal of the sampling capacitor C2 is connected to the ground terminal GND. Thus, a DC voltage signal can be output using the sampling diode D1 and the sampling capacitor C2, which is simple to implement and highly reliable.

[0028] In one embodiment, the peak sampling circuit 22 further includes a first operational amplifier U1. The amplifier circuit 16 is connected to the non-inverting input of the first operational amplifier U1, the inverting input of the first operational amplifier U1 is connected to the voltage detection port 20, and the output of the first operational amplifier U1 is connected to the anode of the sampling diode D1. Thus, the first operational amplifier U1 can directly drive the sampling diode D1 and the sampling capacitor C2, reducing the charging time constant and improving the tracking speed.

[0029] In one embodiment, the peak sampling circuit 22 further includes a pull-down resistor RL connected between the voltage detection port 20 and the ground terminal GND, enabling the output of a DC voltage signal to the voltage detection port 20.

[0030] In one embodiment, the amplifier circuit 16 includes a second operational amplifier U2, an excitation source 15 connected to the non-inverting input of the second operational amplifier U2, and a first capacitor C1 connected between the inverting input and the detection terminal 14 of the second operational amplifier U2. A voltage detection port 20 is connected to the output of the second operational amplifier U2. In this embodiment, a peak sampling circuit 22 is connected between the output of the second operational amplifier U2 and the voltage detection port 20. The amplifier circuit 16 is implemented using the second operational amplifier U2, a simple method.

[0031] In one embodiment, the amplifier circuit 16 further includes a first resistor R1, which is connected between the excitation source 15 and the non-inverting input of the second operational amplifier U2.

[0032] In one embodiment, the amplifier circuit 16 further includes a second resistor R2, which is connected between the detection terminal 14 and the inverting input terminal of the second operational amplifier U2. Alternatively, the second resistor R2 can be connected between the first capacitor C1 and the inverting input terminal of the second operational amplifier U2.

[0033] In one embodiment, the amplifier circuit 16 further includes a third resistor R3. The first end of the third resistor R3 is connected between the first capacitor C1 and the inverting input of the second operational amplifier U2. Alternatively, the first end of the third resistor R3 can be connected between the second resistor R2 and the inverting input of the second operational amplifier U2. The second end of the third resistor R3 is connected between the output of the second operational amplifier U2 and the voltage detection port 20. Alternatively, the second end of the third resistor R3 can be connected between the output of the second operational amplifier U2 and the peak sampling circuit 22.

[0034] In one embodiment, the amplifier circuit 16 further includes a second capacitor Cf, which is connected in parallel with the second operational amplifier U2. The second capacitor Cf can be connected in parallel with a third resistor R3. A first terminal of the second capacitor Cf is connected between the first capacitor C1 and the inverting input terminal of the second operational amplifier U2. A first terminal of the second capacitor Cf can also be connected between the second resistor R2 and the inverting input terminal of the second operational amplifier U2. A second terminal of the second capacitor Cf is connected between the output terminal of the second operational amplifier U2 and the voltage detection port 20. A second terminal of the second capacitor Cf can also be connected between the output terminal of the second operational amplifier U2 and the peak sampling circuit 22. The second capacitor Cf can function as a signal filter.

[0035] exist Figure 3 In the illustrated embodiment, due to the DC blocking effect of the first capacitor C1, the average DC value Vc1 of the output signal passing through the first capacitor C1 is equal to the average value Vref_av of the square wave signal Vref from the excitation source 15, i.e. .

[0036] The formula for calculating the square wave voltage signal Vo1 with DC bias after amplification by amplifier circuit 16 is as follows: Wherein, Vref is the square wave signal output by excitation source 15, Vref_av is the average value of the square wave signal output by excitation source 15, R2 represents the resistance value of the second resistor R2, Rx represents the impedance Rx of the measured pin 13, and R3 represents the resistance value of the third resistor R3.

[0037] A square wave voltage signal Vo1 with DC bias can pass through the peak sampling circuit 22 and output a DC voltage signal Vo3. The DC voltage signal Vo3 is the peak DC signal of the square wave voltage signal Vo1 with DC bias. The controller 17 can determine the impedance Rx of the measured pin 13 based on the DC voltage signal Vo3. The calculation formula for the impedance Rx of the measured pin 13 can be derived from the above formula, as shown below: Where Rx represents the impedance Rx of the measured pin 13, Vo3 is the DC voltage signal output by the peak sampling circuit 22, and Vref_max is the maximum value of the square wave signal Vref of the excitation source 15.

[0038] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A liquid inlet detection circuit, characterized in that, include: The detection end is used to connect to the pin being tested on the connector; Excitation source, used to output square wave signal; An amplifier circuit includes a first input terminal and a second input terminal, wherein the excitation source is connected to the first input terminal; The first capacitor is connected between the second input terminal and the detection terminal; and The controller includes a voltage detection port connected to the output terminal of the amplifier circuit, used to detect the voltage output by the output terminal of the amplifier circuit and determine the impedance of the pin under test.

2. The liquid inlet detection circuit according to claim 1, characterized in that, It also includes a peak sampling circuit, which is connected between the output of the amplifier circuit and the voltage detection port. The controller is used to detect the voltage output by the peak sampling circuit and determine the impedance of the pin under test.

3. The liquid inlet detection circuit according to claim 2, characterized in that, It also includes a ground terminal; the peak sampling circuit includes a sampling diode and a sampling capacitor; the anode of the sampling diode is connected to the output terminal of the amplifier circuit, and the cathode of the sampling diode is connected between the voltage detection port and the first terminal of the sampling capacitor; the second terminal of the sampling capacitor is connected to the ground terminal.

4. The liquid inlet detection circuit according to claim 3, characterized in that, The peak sampling circuit further includes a first operational amplifier, the amplifier circuit being connected to the non-inverting input of the first operational amplifier, the inverting input of the first operational amplifier being connected to the voltage detection port, and the output of the first operational amplifier being connected to the anode of the sampling diode.

5. The liquid inlet detection circuit according to claim 3, characterized in that, The peak sampling circuit also includes a pull-down resistor, which is connected between the voltage detection port and the ground terminal.

6. The liquid inlet detection circuit according to claim 1, characterized in that, The amplifier circuit includes a second operational amplifier, the excitation source is connected to the non-inverting input of the second operational amplifier, the first capacitor is connected between the inverting input of the second operational amplifier and the detection terminal, and the voltage detection port is connected to the output of the second operational amplifier.

7. The liquid inlet detection circuit according to claim 6, characterized in that, The amplification circuit further includes a first resistor connected between the excitation source and the non-inverting input of the second operational amplifier; and / or The amplifier circuit also includes a second resistor connected between the detection terminal and the inverting input terminal of the second operational amplifier.

8. The liquid inlet detection circuit according to claim 6, characterized in that, The amplifier circuit further includes a third resistor, the first end of which is connected between the first capacitor and the inverting input of the second operational amplifier; the second end of which is connected between the output of the second operational amplifier and the voltage detection port.

9. The liquid inlet detection circuit according to claim 6, characterized in that, The amplifier circuit further includes a second capacitor connected in parallel with the second operational amplifier. The first end of the second capacitor is connected between the first capacitor and the inverting input terminal of the second operational amplifier. The second end of the second capacitor is connected between the output terminal of the second operational amplifier and the voltage detection port.

10. An electronic device, characterized in that, It includes a connector and a liquid ingress detection circuit as described in any one of claims 1-9, wherein the connector includes a pin under test.

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