Switching module for preventing negative pressure leakage

Abstract

The utility model aims to provide the switching module for preventing negative pressure leakage, which is low in cost, can solve the problem of negative pressure leakage prevention, and prevents negative pressure from being connected in series with other voltage sources. The circuit comprises an analog switch, a plurality of groups of diodes and a plurality of groups of MOS tubes, the analog switch comprises eight output ports S1 to S8, one interface is connected with a common end D of the analog switch, the other seven interfaces are connected with PP10V, the eight output ports S1 to S8 are all connected with the corresponding MOS tubes through the diodes, the output ports of the analog switch are connected with PN5V / -5V through resistors, and the output ports of the analog switch are connected with the PN5V / -5V through resistors. Wherein the S1 end of one group of MOS tubes is connected with a coil coupling output signal of a product, and the S1 ends of the other groups of MOS tubes are connected with a direct current voltage signal of the product. The device is applied to the technical field of automatic testing.

Description

Technical Field

[0001] This invention relates to the technical field of automated testing, and in particular to a switching module for preventing negative pressure leakage. Background Technology

[0002] ELOAD refers to an electronic load, and MOS refers to a field-effect transistor. An electronic load is a device that dissipates electrical energy by controlling the conduction of its internal power transistors or power transistors. It can accurately detect the load voltage, precisely adjust the load current, and simulate a load short circuit. The simulated load can be inductive, resistive, or capacitive, and the rise time of the capacitive load current can be measured. Generally, there is only one electronic load in the test equipment, but there are multiple power supplies to be tested. Therefore, a switching circuit is needed to switch different power supplies to the electronic load. According to safety regulations, the switching circuit usually needs to implement mutual exclusion, meaning that the electronic load can only be connected to one power supply at a time.

[0003] In consumer electronics testing, commonly used ELAOD switching circuits typically employ mechanical switches or MOSFET switches. Mechanical switches are bulky, have short lifespans, and are expensive; while MOSFETs are small, inexpensive, have fast switching speeds, and long lifespans, making them more widely used in switching circuits. However, due to their internal materials and structure, MOSFETs are prone to leakage, and the appropriate switching method must be adapted to the characteristics of the test power supply. Furthermore, the power supplies under test are generally unipolar, meaning they are either positive or negative voltage sources. However, if some power supplies are not fixed DC voltage sources but rather a combination of DC and AC voltages, the negative AC voltage characteristic of this power supply can cause negative voltage leakage in the MOSFET switching circuit, interfering with other DC voltage sources.

[0004] like Figure 4 As shown, a typical Eload MOS switching circuit consists of three parts: a 3 / 8 decoder, a level switcher, and a MOS transistor switch.

[0005] (1) The U1000 3-8 decoder has a characteristic that only one of its eight output ports Y0~Y7 will output a high level, while the other seven ports will output a low level. This characteristic is used to control one MOSFET to be turned on and the other MOSFETs to be turned off, which is mutual exclusion control.

[0006] (2) The level converter U1001 depends on the project requirements. In this case, an N-channel MOSFET is used. The source of the MOSFET is connected to a voltage source. If the voltage of the voltage source connected to the MOSFET is relatively high, higher than the output level of the 3 / 8 decoder, according to the requirement that the gate voltage of the N-channel MOSFET must be greater than the source voltage to turn on the MOSFET, the control level needs to be raised to be higher than the voltage source in order to control the MOSFET to turn on.

[0007] (3) Q1100~Q1105 are N-channel back-to-back MOSFETs. Each of the six MOSFETs has its S1 terminal connected to a voltage source, and their S2 terminals are all connected to the same ELAOD module. For example, if Y0 is high and Y1~Y7 are low, then Q1100 is turned on, and the other MOSFETs are turned off. If all voltage sources are positive, this control works correctly. However, if the voltage sources are negative, such as in this case where the voltage source connected to Q1105 has AC characteristics and can have negative values, then… Figure 5 As shown, the voltage waveform of WP_AC1 shows a negative voltage condition, that is, there is a negative voltage at the S1 terminal and the voltage at the G terminal is 0V. This may cause the voltage at the G terminal to be greater than the voltage at the S terminal, resulting in abnormal conduction of the MOSFET and voltage leakage. This can cause the two voltage sources to connect and short-circuit, and in severe cases, there is a risk of burning out the circuit board.

[0008] from Figure 6 The simulation diagram shows that MOSFETs Q1 and Q2 form a back-to-back MOSFET structure. The gates (G) of both Q1 and Q2 are connected to GND, which is 0V. The voltage source V1 is connected to the source (S) of Q1. V1 is an alternating positive and negative AC current, resulting in a negative voltage component, as shown in the waveform of the first channel of the oscilloscope. The waveform of the third channel shows that this negative voltage leaks through Q1 and Q2 to the load resistor R1. Therefore, the voltage at the gate (G) must also be negative to prevent this negative voltage leakage problem. Therefore, currently... Figure 4 The commonly used MOS switching circuit structure cannot meet this requirement. Therefore, it is necessary to provide a switching module that prevents negative voltage leakage, is low in cost, can solve the problem of negative voltage leakage, and prevents negative voltage from being connected in series with other voltage sources. Utility Model Content

[0009] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a switching module for preventing negative pressure leakage. It is low in cost, can solve the problem of preventing negative pressure leakage, and avoids negative pressure from being connected in series with other voltage sources.

[0010] The technical solution adopted by this utility model is as follows: This utility model includes an analog switch, several groups of diodes, and several groups of MOSFETs. The analog switch includes 8 output ports S1 to S8, one of which is connected to the common terminal D of the analog switch, and the other 7 ports are connected to PP10V. All 8 output ports S1 to S8 are connected to the corresponding MOSFETs through the diodes. The output ports of the analog switch are connected to PN5V / -5V through resistors. The S1 terminal of one group of MOSFETs is connected to the coil coupling output signal of the product, and the S1 terminal of the other groups of MOSFETs is connected to the DC voltage signal of the product.

[0011] As can be seen from the above scheme, the S1 terminal of one group of MOSFETs is connected to the coil coupling output signal of the product (Bluetooth earphone charging case), which has AC characteristics and serves as the WP_AC1 terminal. The S1 terminals of the other groups of MOSFETs are connected to the DC voltage signal on the product's motherboard. The negative voltage of the WP_AC1 terminal is -3V, and -3V>-5V, meaning that the gate voltage is less than the S1 voltage. The MOSFETs with the WP_AC1 terminal are turned off, so there will be no negative voltage leakage problem, thus preventing negative voltage leakage of the MOSFETs.

[0012] In a preferred embodiment, the number of MOSFETs is six groups, including a first MOSFET, a second MOSFET, a third MOSFET, a fourth MOSFET, a fifth MOSFET, and a sixth MOSFET. The G1 terminal of the first MOSFET is connected to the S1 terminal of the analog switch, the G1 terminal of the second MOSFET is connected to the S2 terminal of the analog switch, the G1 terminal of the third MOSFET is connected to the S3 terminal of the analog switch, the G1 terminal of the fourth MOSFET is connected to the S4 terminal of the analog switch, the G1 terminal of the fifth MOSFET is connected to the S5 terminal of the analog switch, and the G1 terminal of the sixth MOSFET is connected to the S6 terminal of the analog switch.

[0013] In a preferred embodiment, the S1 terminal of the first MOSFET is used as the PP1V2_LS2 terminal, the S1 terminal of the second MOSFET is used as the PP5V_BUBO terminal, the S1 terminal of the third MOSFET is used as the PP1V8_BUCK1 terminal, the S1 terminal of the fourth MOSFET is used as the PP3V3_BUCK1 terminal, the S1 terminal of the fifth MOSFET is used as the PP3V3_LS1 terminal, and the S1 terminal of the sixth MOSFET is used as the WP_AC1 terminal.

[0014] In a preferred embodiment, the number of resistor groups is six, including a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, and a sixth resistor. The S1 terminal of the analog switch is connected to PN5V / -5V via the first resistor, the S2 terminal of the analog switch is connected to PN5V / -5V via the second resistor, the S3 terminal of the analog switch is connected to PN5V / -5V via the third resistor, the S4 terminal of the analog switch is connected to PN5V / -5V via the fourth resistor, the S5 terminal of the analog switch is connected to PN5V / -5V via the fifth resistor, and the S6 terminal of the analog switch is connected to PN5V / -5V via the sixth resistor.

[0015] In a preferred embodiment, the diodes are arranged in six groups, including a first diode, a second diode, a third diode, a fourth diode, a fifth diode, and a sixth diode. The G1 terminal of the first MOSFET is connected to the S1 terminal of the analog switch via the first diode. The G1 terminal of the second MOSFET is connected to the S2 terminal of the analog switch via the second diode. The G1 terminal of the third MOSFET is connected to the S3 terminal of the analog switch via the third diode. The G1 terminal of the fourth MOSFET is connected to the S4 terminal of the analog switch via the fourth diode. The G1 terminal of the fifth MOSFET is connected to the S5 terminal of the analog switch via the fifth diode. The G1 terminal of the sixth MOSFET is connected to the S6 terminal of the analog switch via the sixth diode. Attached Figure Description

[0016] Figure 1 This is a structural block diagram of the present invention;

[0017] Figure 2 This is the circuit schematic diagram of this utility model;

[0018] Figure 3 This is a simulation diagram of the present invention;

[0019] Figure 4 This is a schematic diagram of a conventional Eload switching circuit in the existing technology;

[0020] Figure 5 This is the WP_AC1 waveform diagram of a conventional Eload switching circuit in the prior art;

[0021] Figure 6 This is a simulation diagram of a conventional Eload switching circuit in the existing technology. Detailed Implementation

[0022] like Figures 1 to 2 As shown, in this embodiment, the present invention includes an analog switch 1, several groups of diodes 2, and several groups of MOSFETs 3. The analog switch 1 includes eight output ports S1 to S8, one of which is connected to the common terminal D of the analog switch 1, and the other seven are connected to PP10V. Each of the eight output ports S1 to S8 is connected to the corresponding MOSFET 3 via the diodes 2. The output ports of the analog switch 1 are connected to PN5V / -5V via resistors 4. The S1 terminal of one group of MOSFETs 3 is connected to the coil coupling output signal of the product, and the S1 terminals of the other groups of MOSFETs 3 are connected to the DC voltage signal of the product. The analog switch 1 is model ADG5408BRUZ, and the MOSFETs 3 are model SI4288DY-T1-GE3. The resistance of resistor 4 is 10KΩ.

[0023] like Figure 2 As shown, in this embodiment, the number of groups of MOSFETs 3 is six. The six groups of MOSFETs 3 include a first MOSFET Q1100, a second MOSFET Q1101, a third MOSFET Q1102, a fourth MOSFET Q1103, a fifth MOSFET Q1104, and a sixth MOSFET Q1105. The G1 terminal of the first MOSFET Q1100 is connected to the S1 terminal of the analog switch 1. The G1 terminal of the second MOSFET Q1101 is connected to the S2 terminal of the analog switch 1. The G1 terminal of the third MOSFET Q1102 is connected to the S3 terminal of the analog switch 1. The G1 terminal of the fourth MOSFET Q1103 is connected to the S4 terminal of the analog switch 1. The G1 terminal of the fifth MOSFET Q1104 is connected to the S5 terminal of the analog switch 1. The G1 terminal of the sixth MOSFET Q1105 is connected to the S6 terminal of the analog switch 1.

[0024] The analog switch 1 includes an eight-channel analog switch U1000. Of the eight output ports S1 to S8 of the eight-channel analog switch U1000, only one port can be connected to the common terminal D, while the other seven ports are disconnected from terminal D (connected to PP10V). This is used to control one of the MOS transistors 3 to be turned on, while the MOS transistors 3 in the other ports are turned off, which is mutual exclusion control. For example, controlling the first MOSFET Q1100 to conduct requires controlling the D connection S1 of the analog switch. The voltage at port S1 is 10V, so the voltage of the first MOSFET Q1100 is 10V, which is greater than the voltage at the S1 terminal PP1V2 (1.2V) of the first MOSFET Q1100, thus turning on the first MOSFET Q1100. The other output ports S2~S6 of the eight-channel analog switch U1000 are connected to PN5V (-5V) through the resistor 4, making the level of S2~S6 -5V. Thus, the gate voltage of Q1101~Q1105 is -5V. This -5V is used to prevent negative voltage leakage of the MOSFET. For example, the negative voltage of WP_AC1 of the sixth MOSFET Q1105 is -3V. Since -3V > -5V, the gate voltage of the sixth MOSFET Q1105 is less than the S1 terminal voltage, so the MOSFET is off and there is no problem of negative voltage leakage.

[0025] like Figure 2As shown, in this embodiment, the S1 terminal of the first MOSFET Q1100 is used as the PP1V2_LS2 terminal, the S1 terminal of the second MOSFET Q1101 is used as the PP5V_BUBO terminal, the S1 terminal of the third MOSFET Q1102 is used as the PP1V8_BUCK1 terminal, the S1 terminal of the fourth MOSFET Q1103 is used as the PP3V3_BUCK1 terminal, the S1 terminal of the fifth MOSFET Q1104 is used as the PP3V3_LS1 terminal, and the S1 terminal of the sixth MOSFET Q1105 is used as the WP_AC1 terminal.

[0026] like Figure 2 As shown, in this embodiment, the number of resistors 4 is six groups. The six groups of resistors 4 include a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6. The S1 terminal of the analog switch 1 is connected to PN5V / -5V through the first resistor R1, the S2 terminal of the analog switch 1 is connected to PN5V / -5V through the second resistor R2, the S3 terminal of the analog switch 1 is connected to PN5V / -5V through the third resistor R3, the S4 terminal of the analog switch 1 is connected to PN5V / -5V through the fourth resistor R4, the S5 terminal of the analog switch 1 is connected to PN5V / -5V through the fifth resistor R5, and the S6 terminal of the analog switch 1 is connected to PN5V / -5V through the sixth resistor R6.

[0027] The resistor 4 is a 10K ohm pull-up resistor, with its upper end connected to -5V. When the eight-channel analog switch U1000 is not turned on, the S1~S6 pins are floating. Adding these resistors can ensure that the voltage on the S1~S6 pins of the eight-channel analog switch U1000 is pulled up to -5V, thereby preventing leakage.

[0028] like Figure 2As shown, in this embodiment, the number of diode groups 2 is six. The six groups of diodes 2 include a first diode D1000, a second diode D1001, a third diode D1002, a fourth diode D1003, a fifth diode D1004, and a sixth diode D1005. The G1 terminal of the first MOSFET Q1100 is connected to the S1 terminal of the analog switch 1 via the first diode D1000. The G1 terminal of the second MOSFET Q1101 is connected to the S1 terminal of the analog switch 1 via the second diode D1001. The circuit is connected in two ways: the G1 terminal of the third MOSFET Q1102 is connected to the S3 terminal of the analog switch 1 via the third diode D1002; the G1 terminal of the fourth MOSFET Q1103 is connected to the S4 terminal of the analog switch 1 via the fourth diode D1003; the G1 terminal of the fifth MOSFET Q1104 is connected to the S5 terminal of the analog switch 1 via the fifth diode D1004; and the G1 terminal of the sixth MOSFET Q1105 is connected to the S6 terminal of the analog switch 1 via the sixth diode D1005.

[0029] like Figure 2 As shown, diode 2 is a freewheeling diode. For example, D1000, R1010, and C1015 form a slow-turn-on and fast-turn-off function for the MOSFET. For instance, when controlling the MOSFET Q1100 to turn on, pin 8 (D) and pin 4 (S1) of U1000 will be connected, and the voltage on S1 will become 10V. Because of the presence of R1010 and C1015, the 10V voltage will charge C1015. The ELOAD_Y01 voltage value will slowly rise as C1015 charges. The MOSFET Q1100 will only turn on after the ELOAD_Y01 voltage value rises to a certain value. When turning off the MOSFET, pin 8 (D) and pin 4 (S1) of U1000 will be disconnected. The voltage on C1015 will not immediately become -5V. D1000 and R1010 will form a discharge current loop, quickly discharging the current on the capacitor, allowing the MOSFET to turn off more quickly.

[0030] like Figure 3 As shown, the gates of MOSFETs Q1 and Q2 are connected to V2 -5V via 10K resistors R2 and R3. Even if there is a negative voltage in V1, as long as the negative voltage of V1 is greater than -5V, there will be no negative voltage leakage, as shown by the waveform of the third channel of the oscilloscope.

Claims

1. A switching module for preventing negative pressure leakage, characterized in that: It includes an analog switch (1), several groups of diodes (2), and several groups of MOSFETs (3). The analog switch (1) includes 8 output ports S1 to S8, one of which is connected to the common terminal D of the analog switch (1), and the other 7 ports are connected to PP10V. The 8 output ports S1 to S8 are all connected to the corresponding MOSFETs (3) through the diodes (2). The output ports of the analog switch (1) are connected to PN5V / -5V through resistors (4). The S1 terminal of one group of MOSFETs (3) is connected to the coil coupling output signal of the product, and the S1 terminal of the other groups of MOSFETs (3) is connected to the DC voltage signal of the product.

2. The switching module for preventing negative pressure leakage according to claim 1, characterized in that: The MOSFETs (3) consist of six groups, including a first MOSFET (Q1100), a second MOSFET (Q1101), a third MOSFET (Q1102), a fourth MOSFET (Q1103), a fifth MOSFET (Q1104), and a sixth MOSFET (Q1105). The G1 terminal of the first MOSFET (Q1100) is connected to the S1 terminal of the analog switch (1), and the second MOSFET (Q1101)... The G1 terminal of the third MOS transistor (Q1102) is connected to the S2 terminal of the analog switch (1), the G1 terminal of the fourth MOS transistor (Q1103) is connected to the S4 terminal of the analog switch (1), the G1 terminal of the fifth MOS transistor (Q1104) is connected to the S5 terminal of the analog switch (1), and the G1 terminal of the sixth MOS transistor (Q1105) is connected to the S6 terminal of the analog switch (1).

3. The switching module for preventing negative pressure leakage according to claim 2, characterized in that: The S1 terminal of the first MOSFET (Q1100) is used as the PP1V2_LS2 terminal, the S1 terminal of the second MOSFET (Q1101) is used as the PP5V_BUBO terminal, the S1 terminal of the third MOSFET (Q1102) is used as the PP1V8_BUCK1 terminal, the S1 terminal of the fourth MOSFET (Q1103) is used as the PP3V3_BUCK1 terminal, the S1 terminal of the fifth MOSFET (Q1104) is used as the PP3V3_LS1 terminal, and the S1 terminal of the sixth MOSFET (Q1105) is used as the WP_AC1 terminal.

4. The switching module for preventing negative pressure leakage according to claim 1, characterized in that: The resistors (4) consist of six groups, including a first resistor (R1), a second resistor (R2), a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), and a sixth resistor (R6). The S1 terminal of the analog switch (1) is connected to PN5V / -5V via the first resistor (R1), the S2 terminal of the analog switch (1) is connected to PN5V / -5V via the second resistor (R2), the S3 terminal of the analog switch (1) is connected to PN5V / -5V via the third resistor (R3), the S4 terminal of the analog switch (1) is connected to PN5V / -5V via the fourth resistor (R4), the S5 terminal of the analog switch (1) is connected to PN5V / -5V via the fifth resistor (R5), and the S6 terminal of the analog switch (1) is connected to PN5V / -5V via the sixth resistor (R6).

5. The switching module for preventing negative pressure leakage according to claim 2, characterized in that: The diodes (2) consist of six groups, including a first diode (D1000), a second diode (D1001), a third diode (D1002), a fourth diode (D1003), a fifth diode (D1004), and a sixth diode (D1005). The G1 terminal of the first MOSFET (Q1100) is connected to the S1 terminal of the analog switch (1) via the first diode (D1000), and the G1 terminal of the second MOSFET (Q1101) is connected to the S2 terminal of the analog switch (1) via the second diode (D1001). The G1 terminal of the third MOSFET (Q1102) is connected to the S3 terminal of the analog switch (1) via the third diode (D1002), the G1 terminal of the fourth MOSFET (Q1103) is connected to the S4 terminal of the analog switch (1) via the fourth diode (D1003), the G1 terminal of the fifth MOSFET (Q1104) is connected to the S5 terminal of the analog switch (1) via the fifth diode (D1004), and the G1 terminal of the sixth MOSFET (Q1105) is connected to the S6 terminal of the analog switch (1) via the sixth diode (D1005).

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