Driving circuit, switching circuit and electronic device suitable for negative reference voltage

Abstract

A driving circuit, a switching circuit and an electronic device suitable for a negative reference voltage, the driving circuit suitable for a negative reference voltage comprises: a switch driving module, a first input end is connected with an input voltage signal, a second input end is connected with a negative reference voltage signal, a third input end is used for being connected with an external switch device to form a connection point, and an output end is used for outputting a gate driving voltage according to the reference voltage signal, the input voltage signal and the voltage of the connection point; a compensation module, an output end is used for being connected with the connection point, and when the switch driving module outputs the gate driving voltage, the current of the connection point is automatically compensated to eliminate the load current formed by the reference voltage signal. The driving circuit, the switching circuit and the electronic device suitable for a negative reference voltage improve the compensation precision 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 drive circuit, switching circuit, and electronic device suitable for negative reference voltages. Background Technology

[0002] Switching circuits, such as USB switching circuits, generate a drain current during operation. This drain current flows through a resistor with a large resistance value, which can cause the port of the USB switching circuit to float and experience a floating voltage phenomenon.

[0003] In existing technologies, the pumping current is estimated through simulation and actual measurement, and then compensated by adding an additional adjustable compensation current. However, this fixed compensation method makes it difficult to accurately predict the pumping current. When the compensation current is greater than the pumping current, a positive floating voltage is measured at the switch circuit port; when the compensation current is less than the pumping current, a negative floating voltage is measured at the switch circuit port, resulting in low compensation accuracy. Summary of the Invention

[0004] In view of this, this application provides a drive circuit, a switching circuit, and an electronic device suitable for negative reference voltages, so as to solve the problem of low compensation accuracy when eliminating the port floating voltage of the switching circuit by existing fixed current compensation methods.

[0005] This application provides a driving circuit suitable for negative reference voltages, comprising: a switch driving module, with a first input terminal connected to an input voltage signal, a second input terminal connected to a negative reference voltage signal, and a third input terminal for connecting to an external switching device to form a connection point, and an output terminal for outputting a gate terminal driving voltage according to the reference voltage signal, the input voltage signal, and the voltage of the connection point; and a compensation module, with an output terminal connected to the connection point, which automatically compensates the current of the connection point when the switch driving module outputs the gate terminal driving voltage to eliminate the pumping current formed by the reference voltage signal.

[0006] Optionally, the compensation module includes a compensation unit; the compensation output terminal of the compensation unit is used to connect to the connection point, and is used to control the voltage of the connection point to be equal to zero or to provide compensation current to eliminate the pumping current formed by the reference voltage signal when the voltage of the connection point is the reference voltage signal.

[0007] Optionally, the compensation unit includes at least one of an adjustable current source, a current mirror circuit, and a shunt circuit.

[0008] Optionally, when the compensation unit includes an adjustable current source, the input terminal of the adjustable current source is connected to the power supply voltage, and the output terminal is used to connect to the connection point.

[0009] Optionally, when the compensation unit includes a current mirror circuit, the current mirror circuit includes at least one first switching device and a second switching device.

[0010] The control terminal of the first switching device, the control terminal of the second switching device, the first terminal of the first switching device, the first terminal of the second switching device, and the power supply voltage are all connected together. The second terminal of the first switching device is grounded, and the second terminal of the second switching device is used to connect to the connection point.

[0011] Optionally, when the compensation unit includes a shunt circuit, the shunt circuit includes at least a first resistor and a second resistor;

[0012] One end of the first resistor is connected to one end of the second resistor and the power supply voltage, the other end of the first resistor is grounded, and the other end of the second resistor is used to connect to the connection point.

[0013] Optionally, the switch driving module includes a switching unit and a charge storage unit;

[0014] The first end of the switching unit is used to connect to the connection point, the second end is used to connect to the input end of the charge storage unit, the third end is used to acquire the input voltage signal, and the fourth end is used to acquire the reference voltage signal. The switching unit is used to control the charge storage unit to store charge according to the first clock control signal, and to output the reference voltage signal to the connection point according to the second clock control signal.

[0015] 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 second clock control signal.

[0016] Optionally, the charge storage unit includes at least one energy storage capacitor;

[0017] The two ends of the energy storage capacitor are connected between the third end and the fourth end of the switching unit.

[0018] Optionally, 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 connection point; the first switch and the second switch are controlled by the first clock control signal, and the third switch is controlled by the second clock control signal; the first clock control signal and the second clock control signal are out of phase.

[0019] Optionally, the switching unit 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 second clock control signal to output the gate drive voltage.

[0020] This application also provides a switching circuit, including the aforementioned driving circuit suitable for negative reference voltage and a switching main circuit; the driving circuit is connected between the control terminal and the first switching terminal of the switching main circuit, and the second switching terminal and the third switching terminal of the switching main circuit serve as the input terminal and the output terminal of the switching main circuit, respectively; the driving circuit is used to eliminate the pumping current formed at the first switching terminal.

[0021] Optional,

[0022] The main circuit of the switch includes at least one first power switch and one second power switch;

[0023] The source terminals of the first power switch and the second power switch are connected to form a connection point. 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 and second power switches are connected to the first output terminal of the driving circuit suitable for negative reference voltage. The second output terminal of the driving circuit suitable for negative reference voltage is connected to the connection point. The input terminal of the driving circuit suitable for negative reference voltage is connected to the source terminal of the first power switch. The driving circuit suitable for negative reference voltage provides a gate terminal driving voltage and a compensation current to control the on / off state of the first and second power switches, and automatically compensates the current at the source terminal of the first power switch to eliminate the pumped current formed at the connection point.

[0024] This application also provides an electronic device including the aforementioned switching circuit.

[0025] This application discloses a driving circuit, switching circuit, and electronic device applicable to negative reference voltages. Through a switching driving module, a first input terminal is connected to an input voltage signal, a second input terminal is connected to a negative reference voltage signal, and a third input terminal is used to connect to an external switching device to form a connection point. The output terminal is used to output a gate-end driving voltage based on the reference voltage signal, the input voltage signal, and the voltage of the connection point. A compensation module, with its output terminal connected to the connection point, automatically compensates for the current at the connection point when the switching driving module outputs the gate-end driving voltage to eliminate the pump-out current formed by the reference voltage signal, thereby improving compensation accuracy and eliminating port floating voltage of the switching circuit. Attached Figure Description

[0026] 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.

[0027] Figure 1 This is a schematic diagram of the structure of a drive circuit applicable to a negative reference voltage according to an embodiment of this application;

[0028] Figure 2 This is a schematic diagram of the structure of a drive circuit applicable to a negative reference voltage according to an embodiment of this application;

[0029] Figure 3 This is a diagram showing the relationship between clock signal CLK and clock signal CLKB according to an embodiment of this application;

[0030] Figure 4 This is a schematic diagram of the structure of a drive circuit applicable to a negative reference voltage according to an embodiment of this application;

[0031] Figure 5 This is a schematic diagram of the structure of a drive circuit applicable to a negative reference voltage according to an embodiment of this application;

[0032] Figure 6 This is a schematic diagram of the structure of a switching circuit according to an embodiment of this application. Detailed Implementation

[0033] The inventors discovered that providing a negative voltage to the drive circuit of a power switch in a switching circuit can increase the gate-source voltage VGS of the power switch and reduce its on-resistance. However, this results in a pumped-out current, causing a floating voltage at the port. As described in the background art, in existing technologies, this pumped-out current is estimated through simulation and actual measurement, and then compensated for by adding an additional adjustable compensation current. This fixed compensation method makes it difficult to accurately predict the magnitude of the pumped-out current. When the compensation current is greater than the pumped-out current, a positive floating voltage is measured at the port of the switching circuit; when the compensation current is less than the pumped-out current, a negative floating voltage is measured at the port of the switching circuit, resulting in low compensation accuracy.

[0034] To address the issue of low compensation accuracy when using the fixed current compensation method to eliminate port floating voltage in the switching circuit, this application provides a drive circuit suitable for negative reference voltages. This circuit can automatically compensate to eliminate the pumping current formed by the reference voltage signal, thereby improving compensation accuracy and eliminating port floating voltage in the switching circuit.

[0035] 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.

[0036] Please refer to Figure 1 The present application provides a schematic diagram of the structure of a drive circuit suitable for a negative reference voltage according to an embodiment of the present application.

[0037] The driving circuit 1 applicable to negative reference voltage in this embodiment includes a switch driving module 10 and a compensation module 20.

[0038] The switch driver module 10 has a first input terminal connected to an input voltage signal LV1, a second input terminal connected to a negative reference voltage signal NEG, and a third input terminal IN for connecting to an external switching device to form a connection point. Its output terminal outputs the gate drive voltage GATE based on the reference voltage signal NEG, the input voltage signal LV1, and the voltage at the connection point. The connection point includes one of the source / drain terminals of the external switching device, and is formed by connecting the third input terminal IN of the switch driver module 1 to the external switching device. When this external switching device is used in a switching circuit, it serves as the main switching circuit, and the drain / source terminal of the external switching device corresponding to the connection point serves as a port of the switching circuit.

[0039] The compensation module 20 has an output terminal BOUT that is connected to the connection point to automatically compensate the current at the connection point to eliminate the pumping current formed by the reference voltage signal.

[0040] The driving circuit 1 for negative reference voltage in this embodiment connects an input voltage signal to a first input terminal of a switch driving module 10, a negative reference voltage signal to a second input terminal, and a third input terminal for connection with an external switching device to form a connection point. The output terminal outputs a gate-end driving voltage based on the reference voltage signal, the input voltage signal, and the voltage at the connection point. A compensation module, whose output terminal is connected to the connection point, automatically compensates for the current at the connection point when the switch driving module outputs the gate-end driving voltage, thereby eliminating the pump-out current formed by the reference voltage signal, improving compensation accuracy, and eliminating port floating voltage in the switching circuit.

[0041] In one optional embodiment, the compensation module includes a compensation unit; the compensation output terminal of the compensation unit is connected to the connection point, and when the voltage at the connection point is the reference voltage signal, it controls the voltage at the connection point to be equal to zero or provides a compensation current to eliminate the drain current formed by the reference voltage signal. By providing a compensation current to eliminate the drain current formed by the reference voltage signal NEG, or by controlling the voltage at the connection point to zero through a shunt circuit, the drain current of the reference voltage signal NEG on the connection point is eliminated, thereby improving the compensation accuracy, avoiding floating voltage at the switching circuit port, and improving the reliability of eliminating floating voltage.

[0042] In one optional implementation, the compensation unit includes at least one of an adjustable current source, a current mirror circuit, and a shunt circuit.

[0043] Specifically, the compensation unit can obtain the current in the source and drain terminals of the external switching device through a current sampling circuit or through simulation. Based on this current, at least one of the adjustable current source, current mirror circuit, and shunt circuit can output a compensation current to eliminate the pumping current generated by the negative voltage of the reference voltage signal NEG, thereby improving the compensation accuracy and eliminating the port floating voltage of the switching circuit.

[0044] Please refer to Figure 2 The present application provides a schematic diagram of the structure of a drive circuit suitable for a negative reference voltage according to an embodiment of the present application.

[0045] Switching circuit 2 includes a USB switching circuit. This USB switching circuit includes at least two power switching transistors M1 and M2 and a resistor Rs. Power switching transistors M1 and M2 constitute external switching devices. The source terminals of power switch M1 and M2 are connected to form 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 a driving circuit 1 suitable for a negative reference voltage. Resistor Rs is connected between the input terminal DP / DM and ground. The resistance value of resistor Rs is relatively large; in this application, the resistance value of resistor Rs is equal to 8 megohms. The driving circuit 1, suitable for a negative reference voltage, provides a gate driving voltage, which can control the on / off state of power switches M1 and M2. The reference voltage signal NEG of the driving circuit 1 is a negative voltage to increase the voltage VGS between the gate and source terminals of power switches M1 and M2.

[0046] When the voltage at connection point MID is the reference voltage signal NEG, the compensation module 20 automatically compensates the current at connection point MID. This can eliminate the drain current generated by the reference voltage signal NEG at connection point MID of power switches M1 and M2. Since there is no drain current flowing through resistor Rs, the input terminal DP / DM will not experience a negative voltage phenomenon. That is, when the port DP / DM of the USB switch circuit is floating, there will be no floating voltage phenomenon.

[0047] This embodiment's driving circuit, applicable to negative reference voltages, includes a compensation unit 201 comprising an adjustable current source I2. The input terminal of the adjustable current source I2 is connected to an external power supply VCC, and the compensation output terminal is connected to the connection point MID. The compensation current output by the adjustable current source I2 is adjustable, and its magnitude is obtained based on a current sampling circuit or through simulation.

[0048] The switch driving module includes a switch unit 101 and a charge storage unit 102.

[0049] The first terminal of the switching unit 101 is connected to the connection point MID, 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, and the fourth terminal is used to acquire the reference voltage signal NEG. The switching unit 101 is used to control the charge storage unit 102 to store charge according to the first clock control signal, and to control the voltage of the connection point MID to be the reference voltage signal NEG according to the second clock control signal. The output terminal of the charge storage unit 102 is connected to the gate terminal of an external switching device and is used to output the gate terminal driving voltage according to the second clock control signal.

[0050] The charge storage unit 102 includes at least one energy storage capacitor; the two ends of the energy storage capacitor are connected between the third terminal and the fourth terminal of the switching unit. 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 third and fourth ends 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.

[0051] 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 connection point; the first switch and the second switch are controlled by the first clock control signal, and the third switch is controlled by the second clock control signal; the first clock control signal and the second clock control signal are out of phase.

[0052] 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 second clock control signal to output the gate drive voltage.

[0053] 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.

[0054] 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 of the third switch S3 is connected to one end of the fourth switch S4, and the field terminal of the fourth switch S4 is connected to the gate terminal of an external switching device. One end of the third switch S3 is connected to the energy storage capacitor C. FLY The lower electrode is connected, and the other end is connected to the connection point MID.

[0055] 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 3 The 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.

[0056] The specific working principle of the drive circuit applicable to negative reference voltage 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 gates of power transistors M1 and M2 in the drive circuit 1 applicable to negative reference voltage, which can provide sufficient gate-source voltage VGS to power transistors M1 and M2 under low voltage.

[0057] 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 Upper plate voltage V2 = VMID + (LV1 + NEG), energy storage capacitor C FLY The upper plate voltage V2 is the gate drive voltage GATE output by the switch drive module. Therefore, the switch drive module outputs the gate drive voltage GATE based on the reference voltage signal NEG, the input voltage signal LV1, and the voltage VMID at the connection point. The voltage VGS between the gate and source terminals of power transistors M1 and M2 is LV1 + NEG, increasing the gate-source voltage VGS and reducing the on-resistance.

[0058] However, this drive circuit, which is suitable for negative reference voltages, will generate a drain current from the NEG terminal to the MID terminal during operation, such as... Figure 2 As shown, the presence of NEG is equivalent to connecting an adjustable current source I1 to the connection point MID, which will generate a drain current. This drain current flows through the resistor RS, causing a negative voltage phenomenon at the DP / DM port. The causes of this drain current include two aspects: 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. FLY The lower plate is charged, eventually making V1 = VMID; this process 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.

[0059] To address the aforementioned issues, a compensation unit 201 is used in the drive circuit suitable for negative reference voltages. This compensation unit 201 includes an adjustable current source I2, whose input is connected to the external power supply VCC and whose output is connected to the connection point MID. Specifically, the NEG pump-out current is estimated through simulation, actual measurement, or sampling circuitry. An additional adjustable compensation current I12 is added at the MID terminal node to compensate for and offset the NEG pump-out current, thus eliminating floating voltage at the DP / DM port.

[0060] In one alternative implementation, this application uses a current mirror circuit or a shunt circuit to automatically adjust the compensation current of the connection point MID, which can improve the accuracy of the compensation current and eliminate the phenomenon of excessive floating voltage at the port DP / DM caused by the NEG pumping current to the MID terminal.

[0061] The compensation unit includes a current mirror circuit, which includes at least one first switching device and a second switching device. The control terminal of the first switching device, the control terminal of the second switching device, the first terminal of the first switching device, the first terminal of the second switching device, and the power supply voltage are all connected together. The second terminal of the first switching device is grounded, and the second terminal of the second switching device is used to connect to the connection point.

[0062] Please refer to Figure 4 The present application provides a schematic diagram of the structure of a drive circuit suitable for a negative reference voltage according to an embodiment of the present application.

[0063] The driving circuit applicable to negative reference voltage in this embodiment is the same as described above for the switch driving module, and will not be repeated here.

[0064] In this embodiment, the current mirror circuit includes a first switching device and a second switching device. The first switching device is an NMOS transistor MN1, and the second switching device is an NMOS transistor MN2. In other optional embodiments, the current mirror circuit may include multiple first and second switching devices, and the types of first and second switching devices include transistors, power switches, triodes, and other types of switches.

[0065] In this embodiment, the current mirror circuit also includes a fixed current source I3, which is used to provide current to NMOS transistors MN1 and MN2. The fixed current source I3 can be omitted and the current can be directly provided by the power supply voltage VCC.

[0066] In this embodiment, the input terminal of the fixed current source I3 is connected to the power supply voltage VCC, and the output terminal is connected to the drain terminal of NMOS transistor MN1, the gate terminal of NMOS transistor MN1, the drain terminal of NMOS transistor MN2, and the gate terminal of NMOS transistor MN1. The source terminal of NMOS transistor MN1 is grounded, and the source terminal of NMOS transistor MN2 is connected to the connection point MID.

[0067] The principle behind the drive circuit for negative reference voltages in this embodiment, which eliminates floating voltage at the USB switching circuit port through an adjustable current source circuit, is as follows:

[0068] This current source circuit can automatically adjust the current compensation at connection point MID. The saturation current formula for NMOS transistor MN1 is:

[0069]

[0070] Among them, I D The saturation current of NMOS transistor MN1, μ n For electron migration rate, C ox Capacitance per unit area of ​​gate oxide layer The aspect ratio of the oxide layer, V GS The voltage between the gate and source terminals, V TH This is the threshold voltage.

[0071] From the above formula, it can be seen that when the voltage at the connection point MID is lower than 0V, the voltage V between the gate and source terminals of the NMOS transistor MN2 is... GS2 The voltage V between the gate and source terminals of NMOS transistor MN1 is greater than the voltage V. GS1 V GS2 >V GS1 This causes the current in NMOS transistor MN2 to be greater than the current in NMOS transistor MN1, i.e., I D2 >I D1 The current I D2 The reference voltage signal NEG automatically adjusts the current compensation for the pumped current I11 generated at the connection point MID. When the pumped current I11 increases, it causes the gate-source voltage V of the NMOS transistor MN2 to increase. GS2 The increase leads to an increase in the current I of the NMOS transistor MN2. D2 Increase, so that I D2 =I11; When the pumped current I11 decreases, the gate-source voltage V of the NMOS transistor MN2 decreases. GS2 The current I of the NMOS transistor MN2 decreases, which in turn leads to a decrease in the current I. D2 The current is gradually reduced to achieve automatic adjustment of the compensation current.

[0072] The driving circuit applicable to negative reference voltage in this embodiment uses the negative feedback effect of the current mirror circuit to make the voltage at the MID terminal of the connection point approximately equal to the 0V voltage. Therefore, it can accurately eliminate the phenomenon of excessive floating voltage at the DP / DM port of the USB switch circuit caused by current compensation deviation.

[0073] In one optional embodiment, the compensation unit includes a shunt circuit, which includes at least one first resistor and one second resistor. One end of the first resistor is connected to one end of the second resistor and a power supply voltage, respectively. The other end of the first resistor is grounded, and the other end of the second resistor is used to connect to the connection point. By shunting the current through the resistor, the voltage at the MID terminal of the connection point is clamped, making the voltage at the MID terminal of the connection point close to 0V. This facilitates circuit design and improves the accuracy of current compensation.

[0074] Please refer to Figure 5 The present application provides a schematic diagram of the structure of a drive circuit suitable for a negative reference voltage according to an embodiment of the present application.

[0075] The driving circuit applicable to negative reference voltage in this embodiment is the same as described above for the switch driving module, and will not be repeated here.

[0076] In this embodiment, the compensation unit includes a shunt circuit, which includes a first resistor R1 and a second resistor R2. In other optional embodiments, the current mirror circuit may include multiple first resistors R1 and second resistors R2, or it may include other components, such as capacitors.

[0077] In this embodiment, the current mirror circuit also includes a fixed current source I3, which is used to provide current to the first resistor R1 and the second resistor R2. The fixed current source I3 can be omitted and the current can be directly provided by the power supply voltage VCC.

[0078] In this embodiment, the input terminal of the fixed current source I3 is connected to the power supply voltage VCC, the output terminal is connected to one end of the first resistor R1 and one end of the second resistor R2, the other end of the first resistor R1 is grounded, and the other end of the second resistor R2 is connected to the connection point MID.

[0079] The principle behind the drive circuit for negative reference voltages in this embodiment, which eliminates floating voltage at the USB switching circuit port through an adjustable current source circuit, is as follows:

[0080] This current source circuit clamps the voltage at the MID terminal of the connection point by shunting the current through the first resistor R1 and the second resistor R2. Specifically, when the drawdown current I11 generated by the reference voltage signal NEG at the MID terminal increases, the voltage at the MID terminal decreases, and the current in the branch of the second resistor R2 increases; conversely, when the drawdown current I11 generated by the reference voltage signal NEG at the MID terminal decreases, the voltage at the MID terminal increases, and the current in the branch of the second resistor R2 decreases, ultimately bringing the voltage at the MID terminal close to 0V, thus achieving automatic adjustment of the compensation current. It is evident that automatic adjustment of the compensation current can be achieved through resistor shunting, and this also eliminates the floating voltage at the DP / DM ports of the USB switching circuit.

[0081] The driving circuit applicable to negative reference voltage in this embodiment achieves automatic adjustment of the compensation current through resistor shunt, so that the voltage at the MID terminal of the connection point is eventually approximately equal to the 0V voltage. Therefore, it can accurately eliminate the phenomenon of excessive floating voltage at the DP / DM port of the USB switch circuit caused by current compensation deviation.

[0082] 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.

[0083] The switching circuit of this embodiment includes the driving circuit 1 applicable to negative reference voltage and the switching main circuit 3.

[0084] 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 eliminate the pumping current formed at the first switch terminal.

[0085] In this embodiment, the switching circuit can automatically compensate for the pump-out current formed by the reference voltage signal through the driving circuit 1 applicable to the negative reference voltage, thereby improving the compensation accuracy and eliminating the floating voltage at the port of the switching circuit.

[0086] The main circuit of the switch includes at least one first power switch and one second power switch; the source terminals of the first power switch and the second power switch are connected to form a connection point, the drain terminal of the first power switch serves as the input terminal of the switch circuit, and the drain terminal of the second power switch serves as the output terminal of the switch circuit; the gate terminals of both the first and second power switches are connected to the first output terminal of the drive circuit suitable for negative reference voltage; the second output terminal of the drive circuit suitable for negative reference voltage is connected to the connection point; the input terminal of the drive circuit suitable for negative reference voltage is connected to the source terminal of the first power switch; the drive circuit suitable for negative reference voltage is used to provide a gate terminal drive voltage and a compensation current to control the on or off of the first and second power switches, and to automatically compensate the current at the source terminal of the first power switch to eliminate the pumped current formed at the connection point.

[0087] Specifically, the main switching circuit 3 includes at least one first power switch M71 and one second power switch M72; the source terminal of the first power switch M71 and the source terminal of the second power switch M72 are connected to form a connection point MID, 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 first output terminal of the driving circuit 1 suitable for negative reference voltage; the second output terminal of the driving circuit suitable for negative reference voltage signal is connected to the connection point MID; the driving circuit 1 suitable for negative reference voltage is used to provide a gate terminal driving voltage GATE and a compensation current I to control the conduction or cutoff of the first power switch M71 and the second power switch M72 and automatically compensate the current of the connection point MID to eliminate the pumped current formed at the connection point MID, thereby improving the compensation accuracy and eliminating the port floating voltage of the switching circuit.

[0088] In one optional implementation, the switching circuit includes a USB switching circuit. Since the port of a USB circuit is typically connected to a resistor with a large resistance, the negative voltage signal will generate a pumped current when the USB switching circuit is operating. This pumped current flows through the resistor, causing a floating voltage phenomenon when the DP / DM port of the USB switching circuit is floating. This drive circuit suitable for negative reference voltage can improve compensation accuracy, eliminate port floating voltage, and improve the accuracy of data transmission.

[0089] 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.

[0090] 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 suitable for negative reference voltages, characterized in that, include: The switch driver module has a first input terminal connected to an input voltage signal, a second input terminal connected to a negative reference voltage signal, and a third input terminal for connecting to the source or drain terminal of an external switching device to form a connection point. The output terminal is used to output a gate terminal drive voltage according to the reference voltage signal, the input voltage signal, and the voltage of the connection point. The compensation module has an output terminal connected to the connection point. When the switch drive module outputs the gate drive voltage, it automatically compensates the current of the connection point to eliminate the pumping current formed by the reference voltage signal. The switch driving module includes a switch unit and a charge storage unit; the first end of the switch unit is connected to the connection point, the second end is connected to the input end of the charge storage unit, the third end is used to acquire the input voltage signal, and the fourth end is used to acquire the reference voltage signal. The switch unit is used to control the charge storage unit to store charge according to a first clock control signal, and to output the reference voltage signal to the connection point according to a second clock control signal. The output end of the charge storage unit is connected to the gate end of an external switching device and is used to output the gate end driving voltage according to the second clock control signal.

2. The driving circuit suitable for negative reference voltage as described in claim 1, characterized in that, The compensation module includes a compensation unit; The compensation output terminal of the compensation unit is used to connect to the connection point, and when the voltage of the connection point is the reference voltage signal, it controls the voltage of the connection point to be equal to zero or provides compensation current to eliminate the pumping current formed by the reference voltage signal.

3. The driving circuit suitable for negative reference voltage as described in claim 2, characterized in that, The compensation unit includes at least one of an adjustable current source, a current mirror circuit, and a shunt circuit.

4. The driving circuit suitable for negative reference voltage as described in claim 3, characterized in that, When the compensation unit includes an adjustable current source, the input terminal of the adjustable current source is connected to the power supply voltage, and the output terminal is used to connect to the connection point.

5. The driving circuit suitable for negative reference voltage as described in claim 3, characterized in that, When the compensation unit includes a current mirror circuit, the current mirror circuit includes at least one first switching device and a second switching device. The control terminal of the first switching device, the control terminal of the second switching device, the first terminal of the first switching device, the first terminal of the second switching device, and the power supply voltage are all connected together. The second terminal of the first switching device is grounded, and the second terminal of the second switching device is used to connect to the connection point.

6. The driving circuit suitable for negative reference voltage as described in claim 3, characterized in that, When the compensation unit includes a shunt circuit, the shunt circuit includes at least a first resistor and a second resistor; One end of the first resistor is connected to one end of the second resistor and the power supply voltage, the other end of the first resistor is grounded, and the other end of the second resistor is used to connect to the connection point.

7. The driving circuit suitable for negative reference voltage 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 third end and the fourth end of the switching unit.

8. The driving circuit suitable for negative reference voltage as described in claim 7, 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 connection point. The first switch and the second switch are controlled by the first clock control signal, and the third switch is controlled by the second clock control signal; the first clock control signal and the second clock control signal are out of phase.

9. The driving circuit suitable for negative reference voltage as described in claim 8, 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 turn on according to the second clock control signal to output the gate drive voltage.

10. A switching circuit, characterized in that, Includes the drive circuit and switch body circuit suitable for negative reference voltage as described in any one of claims 1-9; 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 eliminate the pumping current generated at the first switching terminal.

11. The switching circuit as described in claim 10, characterized in that, The main circuit of the switch includes at least one first power switch and one second power switch; The source terminals of the first power switch and the second power switch are connected to form a connection point. 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 and second power switches are connected to the first output terminal of the driving circuit suitable for negative reference voltage. The second output terminal of the driving circuit suitable for negative reference voltage is connected to the connection point. The input terminal of the driving circuit suitable for negative reference voltage is connected to the source terminal of the first power switch. The drive circuit suitable for negative reference voltage is used to provide gate drive voltage and compensation current to control the on or off of the first power switch and the second power switch, and to automatically compensate the current at the source terminal of the first power switch to eliminate the pumping current formed at the connection point.

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

Images