Drive circuit, switching circuit, and electronic device

Abstract

A driving circuit, a switching circuit and an electronic device, the driving circuit comprising: a driving module, a first input end of which is connected with an input voltage signal, a second input end of which is connected with a reference voltage signal, and an output end of which is used for outputting a gate-end driving voltage, the reference voltage signal having a negative value; and an isolation module, an input end of which is used for being connected with an external switching device to form a connection point, and an output end of which is connected with a third input end of the driving module, the isolation module being used for performing signal isolation on the connection point and the third input end. The driving circuit, the switching circuit and the electronic device provided in the application can prevent the reference voltage signal from forming a load current on the connection point, and eliminate the port floating voltage of the switching circuit.

Description

Technical Field

[0001] This application relates to the field of electronic technology, specifically to a driving circuit, a switching circuit, and an electronic device. Background Technology

[0002] Switching circuits, such as USB switching circuits, typically use power switches as switching devices. The gate of the power switch is driven by a driver circuit. The driver circuit uses a negative voltage signal as its input reference voltage, which can increase the voltage VGS between the gate and source of the power switch. A large-value resistor is usually connected to the port of a USB switching circuit.

[0003] Because this negative voltage signal will generate a pumped current to the switch path node when the USB switch circuit is working, and this pumped current will flow through the resistor, causing a floating voltage phenomenon when the DP / DM port of the USB switch circuit is floating. Summary of the Invention

[0004] In view of this, this application provides a driving circuit, a switching circuit, and an electronic device to solve the problem of floating voltage phenomenon at the DP / DM port of the existing switching circuit when the driving circuit is connected to a negative voltage signal.

[0005] This application provides a driving circuit, comprising: a driving module, with a first input terminal connected to an input voltage signal, a second input terminal connected to a reference voltage signal, and an output terminal for outputting a gate-end driving voltage, wherein the value of the reference voltage signal is negative; and an isolation module, with an input terminal for connecting to an external switching device to form a connection point, and an output terminal connected to a third input terminal of the driving module, wherein the isolation module is used to isolate the connection point and the third input terminal from the signal.

[0006] Optionally, the isolation module includes an isolation unit; the input terminal of the isolation unit is connected to the connection point, and the output terminal is connected to the third input terminal of the drive module; the isolation unit is used to output an intermediate voltage according to the voltage of the connection point.

[0007] The driving module is also used to generate the gate driving voltage based on the input voltage signal, the reference voltage signal and the intermediate voltage signal to prevent the reference voltage signal from forming a pumping current at the connection point.

[0008] Optionally, the isolation unit includes at least one of a source follower circuit and a buffer circuit.

[0009] Optionally, when the isolation unit includes a source follower circuit, the source follower circuit includes at least a first switching device and a second switching device; the control terminals of the first switching device and the second switching device are both used to connect to the connection point, the second terminal of the first switching device is connected to the second terminal of the second switching device and the third input terminal of the drive module, the first terminal of the first switching device is connected to the power supply voltage, and the first terminal of the second switching device is connected to ground.

[0010] Optionally, when the isolation unit includes a buffer circuit, the buffer circuit includes an operational amplifier, the non-inverting input of the operational amplifier is connected to the connection point, the inverting input is connected to the output of the operational amplifier and the third input of the driving module, and the operational amplifier is used to control the voltage at the output to be equal to the voltage at the connection point.

[0011] Optionally, the driving module includes a switching unit and a charge storage unit;

[0012] The first terminal of the switching unit is connected to the isolation module, the second terminal is connected to the input terminal of the charge storage unit, the third terminal is used to acquire the input voltage signal, the fourth terminal is used to acquire the reference voltage signal, the fifth terminal is connected to the output terminal of the charge storage unit, and the sixth terminal is used to output the gate driving voltage. The switching unit is used to control the charge storage unit to store charge according to the clock control signal. The output terminal of the charge storage unit is connected to the gate terminal of an external switching device and is used to output the gate driving voltage according to the clock control signal.

[0013] Optionally, the charge storage unit includes at least one energy storage capacitor; the two ends of the energy storage capacitor are connected between the second end of the switching unit and the fifth end of the switching unit.

[0014] Optionally, the switching unit includes a first switch, a second switch, and a third switch;

[0015] One end of the first switch is connected to the lower plate of the energy storage capacitor, and the other end is used to acquire the reference voltage signal; one end of the second switch is used to acquire the input voltage signal, and the other end is connected to the upper plate of the energy storage capacitor; one end of the third switch is connected to the lower plate of the energy storage capacitor, and the other end is used to connect to the output terminal of the isolation module.

[0016] Optionally, the switching unit further includes a fourth switch;

[0017] The fourth switch is connected to the upper plate of the energy storage capacitor and is used to control its conduction according to the clock control signal to output the gate drive voltage.

[0018] This application also provides a switching circuit, including the aforementioned driving circuit and switching body circuit;

[0019] The driving circuit is connected between the control terminal and the first switch terminal of the main switch circuit, and the second switch terminal and the third switch terminal of the main switch circuit serve as the input terminal and the output terminal of the main switch circuit, respectively.

[0020] The driving circuit is used to provide a driving voltage to control the switching body circuit to turn on or off, and to prevent the first switch terminal from generating a pumping current.

[0021] Optionally, the main switching circuit includes at least one first power switch and one second power switch; the source terminal of the first power switch is connected to the source terminal of the second power switch, the drain terminal of the first power switch serves as the input terminal of the switching circuit, and the drain terminal of the second power switch serves as the output terminal of the switching circuit; the gate terminals of both the first power switch and the second power switch are connected to the output terminal of the driving circuit; the source terminals of both the first power switch and the second power switch are connected to the input terminal of the driving circuit; the driving circuit is used to provide a gate terminal driving voltage to control the on or off of the first power switch and the second power switch, and to prevent the source terminals of the first power switch and the second power switch from forming a pumped current.

[0022] This application also provides an electronic device including the aforementioned switching circuit.

[0023] The driving circuit, switching circuit, and electronic device of this application are configured such that an input voltage signal is connected to the first input terminal of the driving module, a reference voltage signal is connected to the second input terminal, and the output terminal is used to output the gate-end driving voltage. The value of the reference voltage signal is negative. The input terminal of the isolation module is used to connect with an external switching device to form a connection point, and the output terminal is connected to the third input terminal of the driving module. The isolation module is used to isolate the connection point and the third input terminal, which can prevent the reference voltage signal from forming a pump current at the connection point and eliminate the port floating voltage of the switching circuit. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a driving circuit according to an embodiment of this application;

[0026] Figure 2This is a schematic diagram of the structure of a driving circuit according to an embodiment of this application;

[0027] Figure 3 This is a schematic diagram of the structure of a driving circuit according to an embodiment of this application;

[0028] Figure 4 This is a diagram showing the relationship between clock signal CLK and clock control signal CLKB according to an embodiment of this application;

[0029] Figure 5 This is a schematic diagram of the structure of a driving circuit according to an embodiment of this application;

[0030] Figure 6 This is a schematic diagram of the structure of a switching circuit according to an embodiment of this application;

[0031] Figure 7 This is a schematic diagram of the structure of a switching circuit according to an embodiment of this application. Detailed Implementation

[0032] The inventors discovered that providing a negative voltage to the drive circuit of the power switch in a switching circuit can increase the gate-source voltage VGS of the power switch and reduce its on-resistance. However, in USB switching circuits, the negative voltage applied to the drive circuit causes the DP / DM ports of the USB switching circuit to float, resulting in a floating voltage phenomenon.

[0033] To address the issue of floating voltage at the DP / DM ports of the USB switching circuit caused by a negative voltage connection to the driver circuit, this application provides a driver circuit. The driver module has a first input terminal connected to an input voltage signal, a second input terminal connected to a reference voltage signal, and an output terminal for outputting a gate-end driving voltage. The reference voltage signal has a negative value. An isolation module has an input terminal connected to an external switching device to form a connection point, and an output terminal connected to a third input terminal of the driver module. The isolation module isolates the connection point from the third input terminal, preventing the reference voltage signal from generating a pump current at the connection point and eliminating floating voltage at the switching circuit ports.

[0034] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In the absence of conflict, the following embodiments and their technical features can be combined with each other.

[0035] Please refer to Figure 1 The diagram below shows the structure of a driving circuit according to an embodiment of this application.

[0036] The driving circuit 1 in this embodiment includes a driving module 10 and an isolation module 20.

[0037] The driving module 10 has a first input terminal connected to the input voltage signal LV1, a second input terminal connected to the reference voltage signal NEG, and an output terminal used to output the gate driving voltage GATE. The value of the reference voltage signal NEG is negative.

[0038] The isolation module 20 has an input terminal IN for connecting to an external switching device to form a connection point, and an output terminal for connecting to the third input terminal of the drive module 10. The isolation module 20 is used to isolate the signal between the connection point and the third input terminal.

[0039] The connection point includes one of the source / drain terminals of the external switching device. When the external device is a power switch, the connection point is the point formed by connecting the input terminal of the isolation module 20 with the source or drain terminal of the power switch. When the external switching device is used in a switching circuit, it serves as the main switching circuit of the switching circuit, and the drain / source terminal of the external switching device corresponding to the connection point serves as the port of the switching circuit.

[0040] In this embodiment, the driving circuit connects an input voltage signal to the first input terminal of the driving module, a reference voltage signal to the second input terminal, and an output terminal for outputting a gate-end driving voltage. The reference voltage signal has a negative value. The isolation module's input terminal is used to connect to an external switching device to form a connection point, and its output terminal is connected to the third input terminal of the driving module. The isolation module isolates the connection point from the third input terminal, preventing the reference voltage signal NEG from forming a pump current at the connection point and eliminating port floating voltage of the switching circuit.

[0041] Please refer to Figure 2 The diagram below shows the structure of a driving circuit according to an embodiment of this application.

[0042] In the driving circuit of this embodiment, the switching circuit 2, such as a USB switching circuit, includes at least two power switching transistors M1 and M2 and a resistor R1. Power switching transistors M1 and M2 are external switching devices. The source terminals of power switch M1 and M2 are connected to form a connection point MID. The drain terminal of power switch M1 serves as the input terminal DP / DM of the USB switching circuit, and the drain terminal of power switch M2 serves as the output terminal D1P / D1M of the USB switching circuit. The gate terminals of power switches M1 and M2 are connected to the driving circuit 1. Resistor R1 is connected between the input terminal DP / DM and ground. The resistance value of resistor R1 is relatively large; in this application, the resistance value of R1 is equal to 8 megohms. The driving circuit 1 provides a gate-end driving voltage, which controls the on / off state of power switches M1 and M2. The reference voltage signal NEG of the driving circuit 1 is a negative voltage, which increases the voltage VGS between the gate and source terminals of power switches M1 and M2.

[0043] By isolating the connection point MID and the third input terminal through the isolation module 20, the connection point MID and the reference voltage signal NEG are isolated, preventing the reference voltage signal NEG from generating a pumping current at the connection point MID of power switches M1 and M2. Since no pumping current flows through the resistor R1, the input terminal DP / DM will not have a negative voltage phenomenon, that is, the USB switch circuit port DP / DM will not have a floating voltage phenomenon when it is floating.

[0044] Specifically, the isolation module 20 can convert the voltage of the connection point MID to the reference voltage signal NEG into the charging current of the voltage source VCC to the reference voltage signal NEG through the isolation circuit, thereby eliminating the floating voltage phenomenon at the port caused by the tapping current of the reference voltage signal NEG to the connection point MID.

[0045] Please refer to Figure 3 The diagram below shows the structure of a driving circuit according to an embodiment of this application.

[0046] The driving circuit of this embodiment includes a driving module comprising a switching unit 101 and a charge storage unit 102.

[0047] The first terminal of the switching unit 101 is connected to the isolation module 20, the second terminal is connected to the input terminal of the charge storage unit 102, the third terminal is used to acquire the input voltage signal LV1, the fourth terminal is used to acquire the reference voltage signal NEG, the fifth terminal is connected to the output terminal of the charge storage unit 102, and the sixth terminal is used to output the gate driving voltage GATE. The switching unit 101 is used to control the charge storage unit 102 to store charge according to the clock control signal; the output terminal of the charge storage unit 102 is used to output the gate driving voltage according to the clock control signal.

[0048] The charge storage unit 102 includes at least one energy storage capacitor C. FLY The energy storage capacitor C FLY The two ends are connected between the second end and the fifth end of the switching unit 101. In this embodiment, the charge storage unit 102 includes at least one energy storage capacitor C. FLY The energy storage capacitor C FLY The two ends are connected between the second end and the fifth end of the switching unit 101. In other optional embodiments, the charge storage unit 102 may include multiple energy storage capacitors, which may be connected in series or in parallel.

[0049] The switching unit 101 includes a first switch, a second switch, and a third switch. One end of the first switch is connected to the lower plate of the energy storage capacitor, and the other end is used to acquire the reference voltage signal. One end of the second switch is used to acquire the input voltage signal, and the other end is connected to the upper plate of the energy storage capacitor. One end of the third switch is connected to the lower plate of the energy storage capacitor, and the other end is used to connect to the output terminal of the isolation module. Specifically, the clock control signal includes a first clock control signal and a second clock control signal. The first switch and the second switch are controlled by the second clock control signal, and the third switch is controlled by the first clock control signal. The first clock control signal and the second clock control signal are out of phase.

[0050] Optionally, the switching unit 101 further includes a fourth switch; the fourth switch is connected to the upper plate of the energy storage capacitor and is used to turn on according to the clock control signal to output the gate drive voltage.

[0051] In this embodiment, the switching unit 101 includes a first switch S1, a second switch S2, a third switch S3, and a fourth switch S4.

[0052] One end of the first switch S1 is connected to the energy storage capacitor C FLY The lower electrode plate is connected, and the other end is used to acquire the reference voltage signal NEG; one end of the second switch S2 is used to acquire the input voltage signal LV1, and the other end is connected to the energy storage capacitor C. FLY The upper plate is connected to one end of the fourth switch S4, and the terminal of the fourth switch S4 is connected to one end of the third switch S3 and the energy storage capacitor C. FLY One end is connected to the lower electrode plate, and the other end is used to connect to the output end of the isolation module.

[0053] The first switch S1 and the second switch S2 are controlled by the first clock control signal CLK, and the third switch S3 and the fourth switch S4 are controlled by the second clock control signal CLKB. Please refer to [link / reference]. Figure 4The relationship diagram of the first clock control signal CLK and the second clock control signal CLKB shows that the frequencies of the first clock control signal CLK and the second clock control signal CLKB are equal but their phases are opposite. When the third switch S3 and the fourth switch S4 are open according to the second clock control signal CLKB, the first switch S1 and the second switch S2 are open according to the first clock control signal CLK; when the third switch S3 and the fourth switch S4 are open according to the second clock control signal CLKB, the first switch S1 and the second switch S2 are open according to the first clock control signal CLK.

[0054] The specific working principle of the drive circuit in this embodiment is as follows: LV1 is the output voltage of the LDO (low-voltage linear regulator), with a voltage value of 3.5V, and NEG is the output voltage of the negative charge pump, with a voltage value of -1.5V. In order to ensure the on-resistance under low voltage, the -1.5V NEG voltage is generated as the reference voltage signal for the gate drive circuit 1 of power transistors M1 and M2, so that sufficient gate-source voltage VGS can be provided to power transistors M1 and M2 under low voltage.

[0055] When CLK is low and CLKB is high, switches S1 / S2 are closed and conducting, while switches S3 / S4 are open, and the energy storage capacitor C... FLY Charge is stored, and the amount of charge stored is Q=C. FLY *(LV1+NEG). When CLKB flips to low, switches S3 / S4 close and conduct, at which point the node voltage at connection point MID is transferred to the energy storage capacitor C. FLY At the lower plate, the voltage at node V1 is equal to the node voltage at connection point MID, i.e., V1 = VMID. Utilizing the property that the charge of a capacitor cannot change abruptly, the energy storage capacitor C... FLY The upper plate voltage V2 = VMID + (LV1 + NEG), and the gate-source voltage VGS between power transistors M1 and M2 is LV1 + NEG. This increases the gate-source voltage VGS and reduces the on-resistance.

[0056] However, without an isolation module, the driver circuit will generate a drain current from the MID terminal via NEG during operation. The presence of NEG is equivalent to connecting a current source to the MID terminal, resulting in a drain current. This drain current flows through resistor R1, causing a negative voltage phenomenon at the DP / DM port. The causes of this drain current are twofold: firstly, when CLK is low, the energy storage capacitor C... FLY The lower plate voltage V1 = NEG = -1.5V. When CLK flips to high level, the MID terminal is connected to the energy storage capacitor C. FLYThe lower plate is charged, eventually making V1=VMID; in this process, it can be equivalent to NEG pulling load on the MID terminal; on the other hand, when the CLK and CLKB clocks have overlapping intervals, a MID-NEG path will be formed, which can also be equivalent to NEG pulling load on the MID terminal.

[0057] The isolation module includes an isolation unit 201. The output of the isolation unit 201 is connected to the third input of the drive module. The input is used to connect to the connection point MID and output an intermediate voltage based on the voltage of the connection point. The drive module is also used to generate the gate drive voltage based on the input voltage signal, the reference voltage signal, and the intermediate voltage signal to prevent the reference voltage signal NEG from causing a drain current to the connection point MID. By outputting an intermediate voltage based on the voltage of the connection point through the isolation unit, a suitable voltage can be provided to the drive module. The drive module can adjust the output gate drive signal according to this voltage to achieve isolation between the MID and NEG nodes, eliminating the phenomenon of excessive floating voltage at the port caused by the drain current of NEG to the MID terminal.

[0058] The isolation unit 201 includes at least one of a source follower circuit and a buffer circuit.

[0059] In this embodiment, the isolation module includes an isolation unit 201, which includes a source follower circuit.

[0060] In this embodiment, the source follower circuit includes a first switching device M3 and a second switching device M4. The control terminals of both the first switching device M3 and the second switching device M4 are connected to the connection point MID. The second terminal of the first switching device M1 is connected to the second terminal of the second switching device M2 and the third input terminal of the drive module. The first terminal of the first switching device M1 is connected to the power supply voltage VCC, and the first terminal of the second switching device M4 is connected to ground. In other optional embodiments, there can be multiple first switching devices M3 and second switching devices M4. By adding a source follower circuit between the MID terminal node and the V1 terminal node, which includes a source follower, and shielding and isolating the two nodes, the influence of NEG on the pump current of the MID terminal can be eliminated.

[0061] Specifically, the first switching device M3 and the second switching device M4 are low-threshold transistors, such as native transistors, to reduce threshold voltage loss. When the input terminal DP / DM of the switching circuit transmits a high level, the first switching device M3 is turned on, and VCC charges the V3 terminal node to approximately the VMID terminal voltage. At this time, the voltage VMID at the V3 terminal node is the intermediate voltage output by the isolation unit. When the input terminal DP / DM of the switching circuit transmits a low level, the second switching device M4 is turned on, discharging the V3 terminal node through ground to the VMID terminal voltage plus a threshold voltage. When the first switching device M3 and the second switching device M4 are PMOS transistors, they discharge the V3 terminal node through ground to the VMID terminal voltage plus a PMOS threshold voltage, i.e., the isolation unit outputs an intermediate voltage. From the above, it can be seen that the energy storage capacitor C... FLY The upper plate voltage is the gate drive voltage output by the drive module. Therefore, the gate drive voltage output by the drive module is related to the intermediate voltage. When the voltage at connection point MID is too high, the isolation unit can reduce the voltage at connection point MID and output a low intermediate voltage. This prevents the risk that during signal transmission, a high-level signal will raise the gate terminals of power transistors M1 and M2 too high, and a low-level signal will cause the VGS of power transistors M1 and M2 to be too high.

[0062] The driving circuit in this embodiment shields and isolates the two nodes by adding a source follower circuit to the MID and V1 nodes, converting the charging current from the MID node to the V1 node into the charging current from the VCC node to the V1 node, thereby eliminating the floating voltage phenomenon caused by the NEG's withdrawal current from the MID terminal. Simulation results show that the floating voltage of the DP / DM / D1P / D1M ports is within 10mV. The reason for this floating voltage is that there is a certain ripple at the gate terminals of power transistors M1 and M2, which inevitably leads to a floating voltage phenomenon at the mV level. This floating voltage meets the preset requirements.

[0063] Please refer to Figure 5 The diagram below shows the structure of a driving circuit according to an embodiment of this application.

[0064] The driving circuit of this embodiment is the same as the one described above, and will not be repeated here.

[0065] The isolation module includes an isolation unit 201, and the isolation unit 201 includes a buffer circuit.

[0066] The buffer circuit includes an operational amplifier OP. In this embodiment, the operational amplifier OP is used instead of the source follower mentioned above. Based on the "virtual short" characteristic of the operational amplifier OP, the operational amplifier OP can be connected in a closed loop. At this time, the voltage of the V3 terminal node is equal to that of the MID terminal node, which can achieve the function of shielding and isolating the MID terminal node and the V1 terminal node.

[0067] In this embodiment, the non-inverting input of the operational amplifier OP is connected to the connection point MID, and the inverting input is connected to the output of the operational amplifier OP and the third input of the driver module. The operational amplifier OP is used to control the voltage at its output to be equal to the voltage at the connection point MID. By controlling the voltage at its output to be equal to the voltage at the connection point MID, the MID terminal node and the V1 terminal node can be shielded and isolated; eliminating the floating voltage phenomenon at the port caused by the NEG's drain current at the MID terminal node.

[0068] Specifically, the output of operational amplifier OP is connected to one end of the third switch S3. When the third switch S3 is closed, the voltage of NEG is equal to the voltage of the output of operational amplifier OP. Since the output of operational amplifier OP is connected to the inverting input of operational amplifier OP, the voltage of the inverting input of operational amplifier OP is NEG. Utilizing the virtual short characteristic of operational amplifier OP, the voltages of the non-inverting and inverting inputs of operational amplifier OP are equal, meaning that the MID voltage is equal to NEG. Operational amplifier OP can achieve shielding and isolation between the MID and V1 terminals, eliminating the floating voltage phenomenon caused by the drain current from NEG at the MID terminal.

[0069] In other alternative implementations, the isolation module in the above-mentioned drive circuit may include both isolation units to further eliminate the port floating voltage phenomenon caused by the NEG's pumped current to the MID terminal node.

[0070] Please refer to Figure 6 The present application provides a schematic diagram of the structure of a switching circuit according to an embodiment of the present application.

[0071] The switching circuit of this embodiment includes the aforementioned driving circuit 1 and the switching main circuit 3.

[0072] The driving circuit 1 is connected between the control terminal and the first switch terminal of the main switch circuit 3. The second switch terminal and the third switch terminal of the main switch circuit 3 serve as the input terminal and the output terminal of the main switch circuit 3, respectively. The driving circuit 1 is used to provide a driving voltage to control the main switch circuit 3 to turn on or off, and to prevent the first switch terminal from generating a pumping current.

[0073] In this embodiment, the switching circuit provides a driving voltage through the aforementioned driving circuit 1 to control the switching main circuit 3 to turn on or off, and prevents the first switching terminal from generating a pumped current, thus eliminating the floating voltage at the switching circuit port.

[0074] Please refer to Figure 7 The present application provides a schematic diagram of the structure of a switching circuit according to an embodiment of the present application.

[0075] The main circuit 3 of the switch in this embodiment includes at least one first power switch M71 and one second power switch M72. In this embodiment, one first power switch M71 and one second power switch M72 are used as an example for illustrative purposes. In other optional embodiments, the number of first power switches M71 and second power switches M72 can be multiple, and the main circuit of the switch can also include other components.

[0076] The source terminal of the first power switch M71 is connected to the source terminal of the second power switch M72. The drain terminal of the first power switch M71 serves as the input terminal of the switching circuit, and the drain terminal of the second power switch M72 serves as the output terminal of the switching circuit. The gate terminals of both the first power switch M71 and the second power switch M72 are connected to the output terminal of the drive circuit 1. The drive circuit 1 is used to provide a gate terminal drive voltage to control the conduction or cutoff of the first power switch M71 and the second power switch M72, and to prevent the formation of a pumped current between the source terminals of the first power switch M71 and the second power switch M72. Since the reference voltage of the driving circuit 1 is negative, the output terminal of the driving circuit 1 is connected to the gate terminal of the first power switch M71 and the gate terminal of the second power switch M72 to output the gate terminal driving voltage; the third input terminal of the driving circuit 1 is connected to the source terminal of the first power switch M71 and the source terminal of the second power switch M72 to compensate the current of the source terminal of the first power switch M71 and the source terminal of the second power switch M72 to prevent the reference voltage signal from forming a pumping current at the source terminal of the first power switch and the source terminal of the second power switch.

[0077] The switching circuit of this embodiment can prevent floating voltage from appearing at the ports of the switching circuit including the first power switch M71 and the second power switch M72 by using the above-described driving circuit 1.

[0078] In one optional implementation, the switching circuit includes a USB switching circuit. Since the USB circuit port is typically connected to a resistor with a large resistance, the negative voltage signal will generate a drain current when the USB switching circuit is operating. This drain current flows through the resistor, causing a floating voltage phenomenon when the DP / DM port of the USB switching circuit is floating. This driving circuit can eliminate the port floating voltage and improve the accuracy of data transmission.

[0079] This application also provides an electronic device including the above-described switching circuit, such as a mobile phone or a computer. The use of this switching circuit improves the stability of the electronic device.

[0080] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, such as the combination of technical features between embodiments, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A driving circuit, characterized in that, include: The driving module has a first input terminal connected to an input voltage signal, a second input terminal connected to a reference voltage signal, and an output terminal for outputting a gate-end driving voltage. The value of the reference voltage signal is negative. An isolation module has an input terminal for connecting to an external switching device to form a connection point, and an output terminal for connecting to the third input terminal of the drive module. The isolation module is used to isolate signals between the connection point and the third input terminal. The connection point includes one of the source / drain terminals of the external switching device. The driving module includes a switching unit and a charge storage unit; the first terminal of the switching unit is connected to the isolation module, the second terminal is connected to the input terminal of the charge storage unit, the third terminal is used to acquire the input voltage signal, the fourth terminal is used to acquire the reference voltage signal, the fifth terminal is connected to the output terminal of the charge storage unit, and the sixth terminal is used to output the gate terminal driving voltage. The switching unit is used to control the charge storage unit to store charge according to the clock control signal. The output terminal of the charge storage unit is connected to the gate terminal of an external switching device, and is used to output the gate terminal drive voltage according to the clock control signal.

2. The driving circuit as described in claim 1, characterized in that, The isolation module includes an isolation unit; The input terminal of the isolation unit is connected to the connection point, and the output terminal is connected to the third input terminal of the drive module. The isolation unit is used to output an intermediate voltage according to the voltage of the connection point. The driving module is also used to generate the gate driving voltage based on the input voltage signal, the reference voltage signal and the intermediate voltage signal to prevent the reference voltage signal from forming a pumping current at the connection point.

3. The driving circuit as described in claim 2, characterized in that, The isolation unit includes at least one of a source follower circuit and a buffer circuit.

4. The driving circuit as described in claim 3, characterized in that, When the isolation unit includes a source follower circuit, the source follower circuit includes at least a first switching device and a second switching device; Both the control terminal of the first switching device and the control terminal of the second switching device are used to connect to the connection point. The second terminal of the first switching device is connected to the second terminal of the second switching device and the third input terminal of the drive module. The first terminal of the first switching device is connected to the power supply voltage, and the first terminal of the second switching device is connected to ground.

5. The driving circuit as described in claim 4, characterized in that, When the isolation unit includes a buffer circuit, the buffer circuit includes an operational amplifier. The non-inverting input of the operational amplifier is connected to the connection point, and the inverting input is connected to the output of the operational amplifier and the third input of the driving module. The operational amplifier is used to control the voltage at the output to be equal to the voltage at the connection point.

6. The driving circuit as described in claim 1, characterized in that, The charge storage unit includes at least one energy storage capacitor; The two ends of the energy storage capacitor are connected between the second end and the fifth end of the switching unit.

7. The driving circuit as described in claim 6, characterized in that, The switching unit includes a first switch, a second switch, and a third switch; One end of the first switch is connected to the lower plate of the energy storage capacitor, and the other end is used to acquire the reference voltage signal; one end of the second switch is used to acquire the input voltage signal, and the other end is connected to the upper plate of the energy storage capacitor; one end of the third switch is connected to the lower plate of the energy storage capacitor, and the other end is used to connect to the output terminal of the isolation module.

8. The driving circuit as described in claim 7, characterized in that, The switching unit also includes a fourth switch; The fourth switch is connected to the upper plate of the energy storage capacitor and is used to control its conduction according to the clock control signal to output the gate drive voltage.

9. A switching circuit, characterized in that, Includes the driving circuit and switching main circuit as described in any one of claims 1-8; The driving circuit is connected between the control terminal and the first switch terminal of the main switch circuit, and the second switch terminal and the third switch terminal of the main switch circuit serve as the input terminal and the output terminal of the main switch circuit, respectively. The driving circuit is used to provide a driving voltage to control the switching body circuit to turn on or off, and to prevent the first switch terminal from generating a pumping current.

10. The switching circuit as described in claim 9, characterized in that, The main circuit of the switch includes at least one first power switch and one second power switch; The source terminal of the first power switch is connected to the source terminal of the second power switch, the drain terminal of the first power switch serves as the input terminal of the switching circuit, and the drain terminal of the second power switch serves as the output terminal of the switching circuit; the gate terminals of both the first power switch and the second power switch are connected to the output terminal of the driving circuit; the source terminals of both the first power switch and the second power switch are connected to the input terminal of the driving circuit. The driving circuit is used to provide a gate-end driving voltage to control the on or off of the first power switch and the second power switch, and to prevent the source terminals of the first power switch and the second power switch from forming a pumped current.

11. An electronic device, characterized in that, Includes the switching circuit described in claim 9 or 10.

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