Over-current protection circuit, chip and electronic equipment

Abstract

The invention relates to the technical field of integrated circuits, and discloses an overcurrent protection circuit, a chip and electronic equipment, and the overcurrent protection circuit comprises a mistaken touch prevention module, a comparison module, a threshold generation module, a current detection module and a power supply. The first end of the comparison module is connected with the current detection module and the mistaken touch prevention module, and the second end of the comparison module is connected with the threshold generation module; the mistaken touch prevention module is connected with the power supply and comprises a first capacitor unit, a first resistor unit and a first switching device; the first end of the first switching device is connected with the first end of the comparison module, the control end of the first switching device is connected with the first end of the first resistor unit and the first end of the first capacitor unit, the second end of the first resistor unit is grounded, the second end of the first switching device is grounded, and the second end of the first capacitor unit is connected with a power supply. Based on the scheme, false triggering of over-current protection can be effectively avoided, and the safety of the chip is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated circuits, and in particular to an overcurrent protection circuit, a chip and an electronic device. Background Art

[0002] A Class D audio power amplifier is an amplifier that converts an input analog audio signal into a series of pulse modulation signals (PWM) with different pulse widths.

[0003] The class D audio power amplifier has two PWM outputs connected to both ends of the speaker. As the speaker impedance continues to decrease and the operating voltage continues to increase, the output power of the class D audio power amplifier continues to increase. Due to the parasitic parameters such as parasitic inductance and resistance in the chip package of the class D audio power amplifier, when the class D audio power amplifier is working at high power, the power supply and ground (ground terminal) connected to the class D audio power amplifier will vibrate underdamped as the output stage of the class D audio power amplifier flips. When the power supply fluctuation becomes larger, the voltage at the positive electrode of the comparator input to the class D audio power amplifier increases, which may cause the positive electrode voltage of the comparator to be greater than or equal to the reference voltage, which is easy to trigger the overcurrent protection in advance, reducing the accuracy of the overcurrent protection function.

[0004] In some embodiments, a large capacitor is connected in series between the positive electrode of the comparator and the ground to avoid false triggering of the overcurrent protection. However, due to the characteristics of capacitors storing charge, the added large capacitor slows down the overcurrent detection speed, causing the time for large current to flow through the chip to be prolonged, and there is a risk of burning the chip. Summary of the invention

[0005] In order to solve the above problems, the embodiments of the present application provide an overcurrent protection circuit, a chip and an electronic device.

[0006] In a first aspect, an embodiment of the present application provides an overcurrent protection circuit, which includes an anti-false touch module, a comparison module, a threshold generation module, a current detection module and a power supply; the first end of the comparison module is respectively connected to the current detection module and the anti-false touch module, and the second end of the comparison module is connected to the threshold generation module; the anti-false touch module is connected to the power supply, and the anti-false touch module includes a first capacitor unit, a first resistor unit and a first switching device; the first end of the first switching device is connected to the first end of the comparison module, the control end of the first switching device is respectively connected to the first end of the first resistor unit and the first end of the first capacitor unit, the second end of the first resistor unit is grounded, the second end of the first switch device is grounded, and the second end of the first capacitor unit is connected to the power supply.

[0007] The present application adds an anti-false touch module to the overcurrent protection circuit. When the power supply in the power amplifier fluctuates greatly, for example, when the power supply output power is greater than the preset threshold due to an upward fluctuation, the anti-false touch module can reduce the voltage at the first end of the comparison module to offset the voltage increase at the first end of the comparison module caused by power supply or ground fluctuations, thereby effectively avoiding the false triggering of the overcurrent protection and ensuring the chip safety. In the embodiment of the present application, there is no need to add a large capacitor to avoid the false triggering of the overcurrent protection, which avoids the speed of the overcurrent detection being affected by the characteristics of the large capacitor storing charge, thereby shortening the time for the large current to flow through the chip, further ensuring the safety of the chip.

[0008] For example, when the overcurrent protection circuit is applied to a class D audio power amplifier, if the class D audio power amplifier works normally, that is, the output power is relatively small and there is no fluctuation, the control end of the first switch device in the anti-false touch module is short-connected to the ground through the first resistor unit, so that the first switch device is not turned on and does not affect the overcurrent protection circuit; when the power supply in the class D audio power amplifier has a large fluctuation, since the gate of the first switch device is connected to the power supply through the first capacitor unit, the first switch device can follow the power supply with equal amplitude fluctuations. For example, when the power supply fluctuates upward, that is, the power supply becomes larger, the gate voltage of the first switch device increases, so that the first switch device is turned on. In this way, the erroneous increase in the voltage of the first terminal of the comparison module caused by the fluctuation of the power supply or the ground is offset, effectively avoiding the false triggering of the overcurrent protection and effectively ensuring the safety of the chip.

[0009] In an implementable manner, the current detection module includes a second switch device, a third switch device, a first resistor, a second resistor, a third resistor, a fourth resistor, a first current source, and a second current source;

[0010] The first end of the second switch device and the control end of the second switch device are both connected to the control end of the third switch device, and the first end of the second switch device is connected to the first end of the first current source, the second end of the second switch device is connected to the first end of the second resistor, the second end of the second resistor is connected to the first end of the first resistor, the second end of the first resistor is connected to the power supply, and the first end of the third resistor is connected to the power supply;

[0011] A first end of the third switch device is respectively connected to a first end of the second current source, a first end of the fourth resistor, a first end of the first switch device and a first end of the comparison module, and a second end of the third switch device is connected to a second end of the third resistor;

[0012] The second end of the first current source is respectively connected to the second end of the second current source, the second end of the fourth resistor, the second end of the first resistor unit, the second end of the first switching device and the threshold generation module, and the second end of the first current source, the second end of the second current source and the second end of the fourth resistor are all grounded.

[0013] In an practicable manner, the threshold generation module includes a fifth resistor and a third current source;

[0014] A first end of the fifth resistor is connected to the second end of the comparison module and the third current source respectively, and a second end of the fifth resistor is grounded.

[0015] In an operative manner, the first switch device includes a first MOS tube, the first capacitor unit includes at least one first capacitor, and the first resistor unit includes at least one first resistor.

[0016] In an practicable manner, the overcurrent protection circuit further includes a first sampling tube;

[0017] The first end of the first sampling tube is connected to the second end of the second resistor and the first end of the first resistor respectively, the second end of the first sampling tube is connected to the output end of the overcurrent protection circuit, and the control end of the first sampling tube is connected to the front-stage driving control circuit of the overcurrent protection circuit.

[0018] In one practicable manner, the overcurrent protection circuit also includes a first power tube; the control end of the first power tube is respectively connected to the control end of the first sampling tube and the pre-stage drive control circuit; the first end of the first power tube is connected to a power supply, and the second end of the first power tube is respectively connected to the second end of the first sampling tube and the output end of the overcurrent protection circuit.

[0019] In an implementable manner, the comparison module is a comparator, the first end of the comparison module is the positive electrode of the comparator, and the second end of the comparison module is the negative electrode of the comparator.

[0020] In an operative manner, the second switch device includes a second MOS transistor, and the third switch device includes a third MOS transistor.

[0021] In a second aspect, the present application provides a chip, comprising the overcurrent protection circuit mentioned in the present application.

[0022] In a third aspect, the present application provides an electronic device, comprising the chip mentioned in the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 According to some embodiments of the present application, a schematic diagram of an overcurrent protection circuit is shown;

[0024] Figure 2According to some embodiments of the present application, a schematic diagram of an overcurrent protection circuit is shown;

[0025] Figure 3 According to some embodiments of the present application, a schematic diagram of an overcurrent protection circuit in a comparative embodiment is shown. DETAILED DESCRIPTION

[0026] The embodiments of the present application include but are not limited to an anti-mis-touch overcurrent protection circuit, a chip and an electronic device. The following first introduces the terms involved in the present application.

[0027] (1) Damped vibration and underdamped vibration

[0028] Damped vibration refers to vibration whose amplitude gradually decays over time due to friction, medium resistance or other energy consumption of the vibration system. It is also called damped vibration or attenuated vibration. Because the amplitude is related to the energy of the vibration, damped vibration is vibration with decreasing energy. Underdamped vibration means that the damping is not large enough, so the damping is not enough to prevent the vibration from crossing the equilibrium position. At this time, the system will perform periodic damped vibration with gradually decreasing amplitude.

[0029] (2) Dead band

[0030] The dead zone is sometimes also called the neutral zone or the inactive zone, which refers to the input signal range in the transfer function of the control system where the corresponding output is zero. In the embodiment of the present application, it means that the upper and lower tubes of the output stage power tube are turned off at the same time.

[0031] As mentioned above, due to the relevant parasitic parameters of the chip packaging in the Class D audio power amplifier, the power supply and ground connected to the Class D audio power amplifier will fluctuate. In addition, in some overcurrent protection circuits, in order to ensure the accuracy of overcurrent detection, the connection position of the current detection module and the power supply or ground in the overcurrent protection circuit is set to be consistent with the connection position of the output stage power tube and the power supply or ground. This causes large fluctuations in the power supply and ground, resulting in an increase in the voltage at the positive electrode of the input comparator, which may cause the positive electrode voltage of the comparator to be greater than or equal to the reference voltage, making it easy to mistakenly trigger the overcurrent protection in advance, reducing the accuracy of the overcurrent protection function.

[0032] In some embodiments, a large capacitor is connected in series between the positive electrode of the comparator and the ground to prevent the positive electrode voltage of the comparator from fluctuating with the fluctuation of the power supply, thereby avoiding false triggering of the overcurrent protection. However, due to the characteristics of capacitors storing charge, the added large capacitor slows down the overcurrent detection speed, causing the time for large current to flow through the chip to be prolonged, and there is a risk of burning the chip.

[0033] In order to solve the above problems, the present application embodiment provides an overcurrent protection circuit, such as Figure 1 As shown, the overcurrent protection circuit includes an anti-false touch module 100, a comparison module 200, a threshold generation module 300, a current detection module 400 and a power supply 500; the first end of the comparison module 200 is respectively connected to the current detection module 400 and the anti-false touch module 100, and the second end of the comparison module 200 is connected to the threshold generation module 300; the anti-false touch module 100 is connected to the power supply 500, and the anti-false touch module 100 includes a first capacitor unit 101, a first resistor unit 102 and a first switch device 103; the first end of the first switch device 103 is connected to the first end of the comparison module 200, the control end of the first switch device 103 is respectively connected to the first end of the first resistor unit 102 and the first end of the first capacitor unit 101, the second end of the first resistor unit 102 is grounded, the second end of the first switch device 103 is grounded, and the second end of the first capacitor unit 101 is connected to the power supply 500.

[0034] When the output power of the power supply 500 is greater than the preset threshold, the first switch device 103 in the false touch prevention module 100 is in the on state, and when the output power of the power supply 500 is less than or equal to the preset threshold, the first switch device 103 is in the off state. In this way, when the output power of the power supply 500 is greater than the preset threshold, the voltage at the first end of the comparison module 200 can be reduced.

[0035] The comparison module 200 is used to output an overcurrent protection trigger signal when it is determined that the voltage at the first end is greater than or equal to the voltage at the second end.

[0036] The embodiment of the present application adds an anti-false touch module 100 in the overcurrent protection circuit. When the power supply 500 in the power amplifier fluctuates greatly, for example, it fluctuates upward so that the output power is greater than a preset threshold, the anti-false touch module 100 can reduce the voltage at the first end of the comparison module 200, offsetting the erroneous increase in the voltage at the first end of the comparison module 200 caused by fluctuations in the power supply 500 or the ground, thereby effectively avoiding false triggering of the overcurrent protection and effectively ensuring chip safety.

[0037] For example, when the overcurrent protection circuit is applied to a class D audio power amplifier, if the class D audio power amplifier works normally, that is, the output power is relatively small and there is no fluctuation, the control end of the first switch device 103 in the anti-false touch module 100 is shorted to the ground through the first resistor unit 102, so that the first switch device 103 is not turned on and does not affect the overcurrent protection circuit; when the power supply 500 in the class D audio power amplifier has a large fluctuation, since the gate of the first switch device 103 is connected to the power supply 500 through the first capacitor unit 101, the first switch device 103 can follow the power supply 500 to fluctuate with equal amplitude. For example, when the power supply 500 fluctuates upward, that is, the power supply 500 becomes larger, the gate voltage of the first switch device 103 increases, so that the first switch device 103 is turned on. In this way, the erroneous increase in the voltage of the first terminal of the comparison module 200 caused by the fluctuation of the power supply 500 or the ground is offset, and the false triggering of the overcurrent protection is effectively avoided, and the chip safety is effectively guaranteed.

[0038] In the embodiment of the present application, there is no need to add a large capacitor to avoid false triggering of the overcurrent protection, which avoids the situation where the speed of overcurrent detection is affected by the characteristics of large capacitors storing charge, thereby shortening the time for large current to flow through the chip, thereby further ensuring the safety of the chip.

[0039] Combine the following Figure 2 The overcurrent protection circuit provided in the embodiments of the present application is described in detail.

[0040] It can be understood that in the embodiment of the present application, the first switching device 103, the second switching device and the third switching device can all be metal-oxide-semiconductor field-effect transistors (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET, MOS tube for short) or triode devices, among which the MOS tube can be a PMOS tube or an NMOS tube.

[0041] In the embodiment of the present application, the overcurrent protection circuit structure of the embodiment of the present application is described by taking the first switching device 103 including the first MOS tube N1, the control end of the first switching device 103 being the gate of the first MOS tube N1, the first end of the first switching device 103 being the drain of the first MOS tube N1, and the second end of the first switching device 103 being the source of the first MOS tube N1 as an example.

[0042] In the embodiment of the present application, the overcurrent protection circuit structure of the embodiment of the present application is described by taking the second switching device including the MOS tube P3, the control end of the second switching device being the gate of the second MOS tube P3, the first end of the second switching device being the drain of the second MOS tube P3, and the second end of the second switching device being the source of the second MOS tube P3 as an example.

[0043] In the embodiment of the present application, the overcurrent protection circuit structure of the embodiment of the present application is described by taking the third switching device including the third MOS tube P4, the control end of the third switching device being the gate of the third MOS tube P4, the first end of the third switching device being the drain of the third MOS tube P4, and the second end of the third switching device being the source of the third MOS tube P4 as an example.

[0044] In some embodiments, the first capacitor unit 101 includes at least one first capacitor C1 , and the first resistor unit 102 includes at least one sixth resistor R6 .

[0045] The present application takes the example that the first capacitor unit 101 includes a first capacitor C1 and the first resistor unit 102 includes a sixth resistor R6 to illustrate the overcurrent protection circuit structure of the embodiment of the present application.

[0046] Figure 2 Taking the upper tube of a class D audio power amplifier as an example, the overcurrent protection circuit provided by the embodiment of the present application is introduced. Figure 2 As shown, the overcurrent protection circuit includes a current generating unit and an overcurrent protection unit, wherein the current generating unit includes a first power tube P1 (or called an upper end tube) and a first sampling tube P2, and the overcurrent protection unit includes an anti-false touch module 100, a comparison module 200, a threshold generating module 300, a current detection module 400 and a power supply 500.

[0047] The gate (control end) of the first sampling tube P2 is respectively connected to the second end of the second resistor R2 and the first end of the first resistor R1 in the current detection module 400, the source (second end) of the first sampling tube P2 is connected to the output end of the overcurrent protection circuit, and the gate (control end) of the first sampling tube P2 is connected to the front-stage driving control circuit of the overcurrent protection circuit.

[0048] The gate (control end) of the first power tube P1 is respectively connected to the gate (control end) of the first sampling tube P2 and the front-stage driving control circuit; the drain (first end) of the first power tube P1 is connected to the power supply 500, and the source (second end) of the first power tube P1 is respectively connected to the second end of the first sampling tube P2 and the output end (OUT) of the overcurrent protection circuit.

[0049] In some embodiments, the first power transistor P1 and the first sampling transistor P2 may be N-channel MOS transistors or P-channel MOS transistors. The first power transistor P1 and the first sampling transistor P2 are of the same type.

[0050] The current detection module 400 is used to detect the current in the overcurrent protection circuit (sampling current I S), the current detection module 400 includes a second MOS transistor P3, a third MOS transistor P4, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first current source A1 and a second current source A2;

[0051] The first end of the second MOS transistor P3 and the control end of the second MOS transistor P3 are both connected to the control end of the third MOS transistor P4, and the first end of the second MOS transistor P3 is connected to the first end of the first current source A1, the second end of the second MOS transistor P3 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is connected to the first end of the first resistor R1, the second end of the first resistor R1 is connected to the power source 500 and the first end of the third resistor R3, and the first end of the third resistor R3 is connected to the power source 500;

[0052] The first end of the third MOS transistor P4 is respectively connected to the first end of the second current source A2, the first end of the fourth resistor R4, the first end of the first MOS transistor N1 and the first end of the comparison module 200, and the second end of the third MOS transistor P4 is connected to the second end of the third resistor R3;

[0053] The second end of the first current source A1 is respectively connected to the second end of the second current source A2, the second end of the fourth resistor R4, the second end of the sixth resistor R6, the second end of the first MOS transistor N1 and the threshold generation module 300, and the second end of the first current source A1, the second end of the second current source A2 and the second end of the fourth resistor R4 are all grounded. The first current source A1 provides a current K 1 I b , the first current source provides a current K 2 I b , where K 1 and K 2 are the coefficients corresponding to the first current source A1 and the second current source A2, I b are the currents corresponding to the first current source A1 and the second current source A2.

[0054] The first end of the comparison module 200 is connected to the current detection module 400 and the anti-false touch module 100 respectively, and the second end of the comparison module 200 is connected to the threshold generation module 300. The comparison module 200 is a comparator, the first end of the comparison module 200 is the positive electrode of the comparator, and the second end of the comparison module 200 is the negative electrode of the comparator. The comparison module 200 is used to obtain the threshold voltage (negative electrode voltage) generated by the threshold generation module 300, and to obtain the voltage (positive electrode voltage of the comparator) generated by the current output by the power supply 500 detected by the current detection module 400, and output an overcurrent protection trigger signal when it is detected that the positive electrode voltage is greater than or equal to the negative electrode voltage.

[0055] The anti-mistaken-touch module 100 is connected to the power supply 500, and the anti-mistaken-touch module 100 includes a first capacitor C1, a sixth resistor R6 and a first MOS tube N1;

[0056] The first end of the first MOS transistor N1 is connected to the first end of the comparison module 200, the control end of the first MOS transistor N1 is respectively connected to the first end of the sixth resistor R6 and the first end of the first capacitor C1, the second end of the sixth resistor R6 is grounded, the second end of the first MOS transistor N1 is grounded, and the second end of the first capacitor C1 is connected to the power supply 500. The anti-false touch module 100 is used to reduce the positive voltage of the comparator due to the fluctuation of the power supply 500 and the ground, and avoid false triggering of overcurrent protection.

[0057] The threshold generation module 300 is used to generate a threshold voltage for overcurrent protection (negative voltage of the comparator). The threshold generation module 300 includes a fifth resistor R5 and a third current source A3;

[0058] The first end of the fifth resistor R5 is respectively connected to the second end of the comparator and the third current source A3, the second end of the fifth resistor R5 is respectively connected to the second end of the first current source A1, the second end of the second current source A2, the second end of the fourth resistor R4, the second end of the sixth resistor R6 and the second end of the first MOS transistor N1, and the second end of the fifth resistor R5 is grounded. The third current source A3 provides a current K 3 I b , where K 3 is the coefficient corresponding to the third current source A3, I b is the current corresponding to the third current source.

[0059] It can be understood that the overcurrent protection circuit may further include a second power tube P5 (or referred to as a lower end tube), a second sampling tube P6 and an overcurrent protection unit corresponding to the lower end tube.

[0060] In some embodiments, the drain of the second power tube P5 can be connected to the source of the first power tube P1 and the speaker (output end), respectively, the gate of the second power tube P5 can be connected to the gate of the second sampling tube P6 and the front-stage driving circuit corresponding to the lower end tube, respectively, the source of the second power tube P5 can be grounded, the drain of the second sampling tube P6 is connected to the source of the first sampling tube P2 and the speaker, and the source of the second sampling tube P6 is connected to the overcurrent protection unit corresponding to the corresponding lower end tube.

[0061] It can be understood that when the output stage power tubes (upper tube and lower tube) are turned on alternately, the current on the speaker will flow from the turned-on tube or from the closed tube substrate to the power supply (PVDD) 500 and the power ground PGND. At this time, the overcurrent protection module outputs the current to the corresponding current detection module (for example, the current detection module 400 in the overcurrent protection unit corresponding to the upper tube and the current detection module corresponding to the lower tube) through the sampling tube (for example, the first sampling tube P2 and the second sampling tube P6), and the generated voltage is compared with the threshold voltage to observe whether the output current is too large. If so, all outputs of the chip will be turned off, so that the current flowing through the power tube is reduced to protect the chip from being burned.

[0062] refer to Figure 2 In the anti-false touch module 100, when the class D audio power amplifier is working normally, that is, the output power of the power supply 500 is low power (for example, low power can refer to power less than or equal to a preset threshold value) and the output is stable, the gate of the first MOS tube N1 is shorted to the ground through the resistor R6, so that the first MOS tube N1 is turned off, and the overcurrent protection circuit is not affected. When the output power of the power supply 500 fluctuates greatly, since the gate of the first MOS tube N1 is connected to the power supply 500 through the capacitor C1, the first MOS tube N1 can follow the power supply 500 to fluctuate with equal amplitude. For example, when the power supply 500 fluctuates upward (the power supply 500 becomes larger, for example, the output power of the power supply 500 is greater than the preset threshold value, that is, the output power of the power supply 500 is high power), the gate voltage of the first MOS tube N1 increases, so that the first MOS tube N1 is turned on. According to the characteristics of the voltage division of the series circuit, since the first MOS tube N1 is turned on, the voltage of the Vy point connected to the first MOS tube N1 is reduced, so that the positive voltage of the comparator connected to the Vy point is reduced. This avoids the overcurrent protection being falsely triggered when the positive voltage of the comparator is greater than the negative voltage due to the fluctuation of the power supply 500. When the fluctuation of the power supply 500 is restored, the first MOS tube N1 returns to the cut-off state, which does not affect the overcurrent protection circuit.

[0063] The present application adds an anti-false touch module 100 to the overcurrent protection circuit, and turns on the first MOS tube N1 in the anti-false touch module 100 to offset the false increase in the voltage value (positive voltage of the comparator) caused by the power supply 500 or ground fluctuation, thereby effectively avoiding the false triggering of the overcurrent protection. In addition, the capacitor size in the embodiment of the present application does not need to be too large, which avoids the speed of overcurrent detection being affected by the characteristics of large capacitors storing charge, shortens the time for large current to flow through the chip, and can better protect the chip safety.

[0064] Combine the following Figure 3 , an overcurrent detection circuit in a comparative embodiment is introduced. and Figure 2 The difference is Figure 3The over-current detection circuit illustrated in FIG. 1 does not include the false touch prevention module 100 .

[0065] like Figure 3 As shown, the overcurrent protection circuit includes a current generating unit and an overcurrent protection unit, wherein the current generating unit includes a first power tube P1 (or called an upper end tube) and a first sampling tube P2, and the overcurrent protection unit includes a comparison module 200, a threshold generation module 300, a current detection module 400 and a power supply 500.

[0066] The gate (control end) of the first sampling tube P2 is respectively connected to the second end of the second resistor R2 and the first end of the first resistor R1 in the current detection module 400, the source (second end) of the first sampling tube P2 is connected to the output end of the overcurrent protection circuit, and the gate (control end) of the first sampling tube P2 is connected to the front-stage drive control circuit of the overcurrent protection circuit for receiving the front-stage drive signal (UP-IN).

[0067] The gate (control end) of the first power tube is respectively connected to the gate (control end) of the first sampling tube P2 and the front-stage driving control circuit; the drain (first end) of the first power tube P1 is connected to the power supply 500, and the source (second end) of the first power tube P1 is respectively connected to the second end of the first sampling tube P2 and the output end (OUT) of the overcurrent protection circuit.

[0068] In some embodiments, the power transistor P1 and the sampling transistor P2 may be N-channel MOS transistors or P-channel MOS transistors. The power transistor P1 and the sampling transistor P2 are of the same type.

[0069] The current detection module 400 is used to detect the current in the overcurrent protection circuit. The current detection module 400 includes a second MOS transistor P3, a third MOS transistor P4, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first current source A1 and a second current source A2;

[0070] The first end of the second MOS transistor P3 and the control end of the second MOS transistor P3 are both connected to the control end of the third MOS transistor P4, and the first end of the second MOS transistor P3 is connected to the first end of the first current source A1, the second end of the second MOS transistor P3 is connected to the first end of the second resistor R2, the second end of the second resistor R2 is connected to the first end of the first resistor R1, the second end of the first resistor R1 is connected to the power source 500 and the first end of the third resistor R3, and the first end of the third resistor R3 is connected to the power source 500;

[0071] The first end of the third MOS transistor P4 is respectively connected to the first end of the second current source A2, the first end of the fourth resistor R4, and the first end of the comparison module 200, and the second end of the third MOS transistor P4 is connected to the second end of the third resistor R3;

[0072] The second end of the first current source A1 is respectively connected to the second end of the second current source A2, the second end of the fourth resistor R4, the second end of the sixth resistor R6 and the threshold generation module 300, and the second end of the first current source A1, the second end of the second current source A2 and the second end of the fourth resistor R4 are all grounded.

[0073] The first end of the comparison module 200 is connected to the current detection module 400, and the second end of the comparison module 200 is connected to the threshold generation module 300. The comparison module 200 is a comparator, the first end of the comparison module 200 is the positive electrode of the comparator, and the second end of the comparison module 200 is the negative electrode of the comparator. The comparison module 200 is used to obtain the threshold voltage (negative electrode voltage) generated by the threshold generation module 300, and to obtain the voltage (positive electrode voltage of the comparator) generated by the current output by the power supply 500 detected by the current detection module 400, and output an overcurrent protection trigger signal when it is detected that the positive electrode voltage is greater than or equal to the negative electrode voltage.

[0074] The threshold generation module 300 is used to generate a threshold voltage for overcurrent protection (negative voltage of the comparator). The threshold generation module 300 includes a fifth resistor R5 and a third current source A3;

[0075] The first end of the fifth resistor R5 is respectively connected to the second end of the comparator and the third current source A3, the second end of the fifth resistor R5 is respectively connected to the second end of the first current source A1, the second end of the second current source A2, the second end of the fourth resistor R4, and the second end of the sixth resistor R6, and the second end of the fifth resistor R5 is grounded.

[0076] It can be understood that the overcurrent protection circuit may further include a second power tube P5 (or referred to as a lower end tube), a second sampling tube P6, and an overcurrent protection unit corresponding to the lower end tube.

[0077] In some embodiments, the drain of the second power tube P5 can be connected to the source level of the first power tube P1 and the speaker (output end) respectively, the gate of the second power tube P5 can be connected to the gate of the second sampling tube P6 and the front-stage driving circuit corresponding to the lower tube respectively, the source level of the second power tube P5 can be grounded, the drain level of the second sampling tube P6 is connected to the source level of the first sampling tube P2 and the speaker, and the source level of the second sampling tube P6 is connected to the second overcurrent protection unit.

[0078] In some embodiments, the comparator can output an overcurrent protection trigger signal to control the working state of the class D audio power amplifier. Specifically, the positive voltage of the comparator (Vy point voltage) is compared with the negative voltage of the comparator (Vx point voltage): when the positive voltage of the comparator (Vy point voltage) is less than the negative voltage of the comparator (Vx point voltage), the comparator outputs a low level, and the class D audio amplifier works normally; when the positive voltage of the comparator (Vy point voltage) is greater than or equal to the negative voltage of the comparator (Vx point voltage), the comparator outputs a high level (outputs an overcurrent protection trigger signal), and the class D audio power amplifier stops working and enters the overcurrent protection state.

[0079] In some embodiments, in order to ensure the accuracy of overcurrent detection, the power supply 500 and ground in the current detection module 400 are connected consistently with the power supply 500 and ground of the power tube P1 and the power tube P5, resulting in large fluctuations in the power supply 500 and ground during overcurrent detection at high power, which can easily cause the overcurrent protection to be triggered prematurely, thereby reducing the accuracy of the overcurrent protection function.

[0080] In some embodiments, in order to protect the normal operation of the chip, the output stage of the Class D audio power amplifier adopts dead zone technology to prevent the output stage power tube P1 and the power tube P5 from being turned on at the same time, generating a large current and burning the chip. During the dead zone process, the power tube P1 and the power tube P5 of the output stage are in the cut-off state at the same time, so that the load current flows through the substrate of the power tube (a structural component in the power tube). However, under high-power applications, due to the influence of parasitic parameters in the chip package and the edge flipping of the output stage power tube P1 and the power tube P5, the power supply 500 and the ground of the chip will produce large fluctuations.

[0081] refer to Figure 3 When the power supply 500 fluctuates greatly, the source voltage of the MOS transistor P3 (the voltage at point V1) and the source voltage of the MOS transistor P4 (the voltage at point V2) in the current detection module 400 fluctuate. For example, when the power supply 500 fluctuates upward (when the value of the power supply 500 increases), the voltage at point V1 and the voltage at point V2 increase, causing the current I flowing through the resistor R4 to 4 Increases, and at the same time, the voltage at the first end of the resistor R4 (the voltage at point Vy) increases, causing the positive voltage of the comparator connected to point Vy to increase. When the positive voltage of the comparator increases to be greater than the negative voltage of the comparator, the overcurrent protection is triggered, causing the overcurrent protection to be falsely triggered.

[0082] In the embodiment of the present application, by adding an anti-false touch module 100 in the overcurrent protection circuit, when the class D audio power amplifier is working normally, the gate of the first MOS tube in the anti-false touch module 100 is shorted to the ground through the first resistor R1, so that the first MOS tube is not turned on and does not affect the overcurrent protection circuit; when the power supply 500 in the class D audio power amplifier has a large fluctuation, since the gate of the first MOS tube is connected to the power supply 500 through the first capacitor, the first MOS tube can follow the power supply 500 with equal amplitude fluctuations, offsetting the positive voltage of the comparator caused by the power supply 500 or ground fluctuations, effectively avoiding the false triggering of the overcurrent protection and effectively ensuring the safety of the chip. That is, in the embodiment of the present application, there is no need to avoid the false triggering of the overcurrent protection by adding a large capacitor. It avoids affecting the speed of overcurrent detection due to the characteristics of large capacitors storing charge, shortening the time for large currents to flow through the chip, and further ensuring the safety of the chip.

[0083] The present application provides a chip, including the overcurrent protection circuit mentioned in the present application.

[0084] The present application provides an electronic device, comprising the chip mentioned in the present application.

[0085] In the accompanying drawings, some structural or method features may be shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be required. Instead, in some embodiments, these features may be arranged in a manner and / or order different from that shown in the illustrative drawings. In addition, the inclusion of structural or method features in a particular figure does not mean that such features are required in all embodiments, and in some embodiments, these features may not be included or may be combined with other features.

[0086] It should be noted that the units / modules mentioned in the various device embodiments of the present invention are all logical units / modules. Physically, a logical unit / module can be a physical unit / module, or a part of a physical unit / module, or can be implemented as a combination of multiple physical units / modules. The physical implementation of these logical units / modules themselves is not the most important. The combination of functions implemented by these logical units / modules is the key to solving the technical problems proposed by the present invention. In addition, in order to highlight the innovative part of the present invention, the above-mentioned device embodiments of the present invention do not introduce units / modules that are not closely related to solving the technical problems proposed by the present invention, which does not mean that there are no other units / modules in the above-mentioned device embodiments.

[0087] It should be noted that in the examples and description of this patent, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "including one" do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0088] While the present invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention.

Claims

1. An overcurrent protection circuit, characterized in that: The overcurrent protection circuit includes an anti-false touch module, a comparison module, a threshold generation module, a current detection module and a power supply; The first end of the comparison module is connected to the current detection module and the false touch prevention module respectively, and the second end of the comparison module is connected to the threshold generation module; The anti-mistaken-touch module is connected to the power supply, and the anti-mistaken-touch module includes a first capacitor unit, a first resistor unit and a first switch device; The first end of the first switching device is connected to the first end of the comparison module, the control end of the first switching device is respectively connected to the first end of the first resistance unit and the first end of the first capacitance unit, the second end of the first resistance unit is grounded, the second end of the first switching device is grounded, and the second end of the first capacitance unit is connected to the power supply.

2. The overcurrent protection circuit according to claim 1, characterized in that: The current detection module includes a second switch device, a third switch device, a first resistor, a second resistor, a third resistor, a fourth resistor, a first current source and a second current source; The first end of the second switch device and the control end of the second switch device are both connected to the control end of the third switch device, and the first end of the second switch device is connected to the first end of the first current source, the second end of the second switch device is connected to the first end of the second resistor, the second end of the second resistor is connected to the first end of the first resistor, the second end of the first resistor is connected to the power source, and the first end of the third resistor is connected to the power source; The first end of the third switch device is respectively connected to the first end of the second current source, the first end of the fourth resistor, the first end of the first switch device and the first end of the comparison module, and the second end of the third switch device is connected to the second end of the third resistor; The second end of the first current source is respectively connected to the second end of the second current source, the second end of the fourth resistor, the second end of the first resistor unit, the second end of the first switching device and the threshold generating module, and the second end of the first current source, the second end of the second current source and the second end of the fourth resistor are all grounded.

3. The overcurrent protection circuit according to claim 2, characterized in that: The threshold generation module includes a fifth resistor and a third current source; The first end of the fifth resistor is respectively connected to the second end of the comparison module and the third current source, and the second end of the fifth resistor is grounded.

4. The overcurrent protection circuit according to any one of claims 1 to 3, characterized in that: The first switch device includes a first MOS tube, the first capacitor unit includes at least one first capacitor, and the first resistor unit includes at least one first resistor.

5. The overcurrent protection circuit according to claim 2 or 3, characterized in that: Also included is a first sampling tube; The first end of the first sampling tube is connected to the second end of the second resistor and the first end of the first resistor respectively, the second end of the first sampling tube is connected to the output end of the overcurrent protection circuit, and the control end of the first sampling tube is connected to the front-stage driving control circuit of the overcurrent protection circuit.

6. The overcurrent protection circuit according to claim 5, characterized in that: Also included is a first power tube; The control end of the first power tube is respectively connected to the control end of the first sampling tube and the front-stage drive control circuit; The first end of the first power tube is connected to the power source, and the second end of the first power tube is respectively connected to the second end of the first sampling tube and the output end of the overcurrent protection circuit.

7. The overcurrent protection circuit according to any one of claims 1 to 3, characterized in that: The comparison module is a comparator, the first end of the comparison module is the positive electrode of the comparator, and the second end of the comparison module is the negative electrode of the comparator.

8. The overcurrent protection circuit according to claim 2 or 3, characterized in that: The second switch device includes a second MOS transistor, and the third switch device includes a third MOS transistor.

9. A chip, characterized in that: The chip includes the overcurrent protection circuit according to any one of claims 1 to 8.

10. An electronic device, characterized in that: Comprising the chip as claimed in claim 9.

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