Overcurrent detection circuit and digital power amplifier device

Abstract

The present application relates to the technical field of digital power amplifiers, and provides an overcurrent detection circuit and a digital power amplifier device. The overcurrent detection circuit is connected to a digital power amplifier circuit, a gate of a field effect transistor in the digital power amplifier circuit is connected to an output end of a pulse signal generation circuit, a source of the field effect transistor is connected to a power amplifier output end, and a drain of the field effect transistor is connected to a power supply; an input end of the overcurrent detection circuit is connected to the gate of the field effect transistor, a first detection end is connected to the drain of the field effect transistor, a second detection end is connected to the source of the first field effect transistor, and the first detection end is electrically connected to the input end; the overcurrent detection circuit is used for outputting a power amplifier protection signal when it is detected, by means of the first detection end and the second detection end, that a current passing through the field effect transistor exceeds a preset value. Embodiments of the present application can implement timely detection of overcurrent of a field effect transistor, effectively reduce the possibility of damage to a digital power amplifier circuit, and prolong the service life of the digital power amplifier circuit.

Description

Overcurrent detection circuit and digital power amplifier device TECHNICAL FIELD

[0001] The present application relates to the technical field of digital power amplifier, in particular, the present application relates to an overcurrent detection circuit and a digital power amplifier device. BACKGROUND

[0002] The digital power amplifier is a kind of amplifier with the characteristics of small distortion, low noise, large dynamic range, etc., which is incomparable to traditional power amplifier in terms of tone coldness, analytical power, background quietness and low-frequency shock intensity. Therefore, it is widely used in home theater, sound system, stereo record player, servo amplifier and other electronic systems.

[0003] In actual use, the digital power amplifier may generate excessive current (i.e., overcurrent) due to audio signal, power supply or abnormal working of itself, and the excessive current may damage the power amplifier tube (field effect transistor) in the digital power amplifier circuit, thereby causing circuit damage. To avoid this situation, the overcurrent condition of the digital circuit needs to be detected in time so as to be processed quickly. SUMMARY

[0004] The present application provides an overcurrent detection circuit and a digital power amplifier device, which can solve the problem of the need for rapid overcurrent detection. In order to achieve this purpose, the present application provides the following several schemes.

[0005] According to an aspect of the present application, an overcurrent detection circuit is provided, which is connected with a digital power amplifier circuit, the digital power amplifier circuit includes a pulse signal generation circuit and a high-level conducting field effect transistor, the gate of the field effect transistor is connected with the output end of the pulse signal generation circuit, the source is connected with the power amplifier output end, and the drain is connected with the power supply;

[0006] The overcurrent detection circuit includes an input end, a first detection end and a second detection end, the input end is connected with the gate of the field effect transistor, the first detection end is connected with the drain of the field effect transistor, the second detection end is connected with the source of the field effect transistor, and the first detection end is electrically connected with the input end, and the overcurrent detection circuit is used for outputting a power amplifier protection signal when the current through the field effect transistor is detected to exceed a preset value through the first detection end and the second detection end.

[0007] In a possible implementation, the power supply includes a positive power supply and a negative power supply, the output end of the digital power amplifier circuit includes a first output end and a second output end, the first output end and the second output end output different time periods of high level in the same pwm period, the field effect transistor includes a first field effect transistor and a second field effect transistor, the gate of the first field effect transistor is connected with the first output end, the gate of the second field effect transistor is connected with the second output end, the drain of the first field effect transistor and the drain of the second field effect transistor are connected with the overcurrent detection circuit, and the drain of the first field effect transistor is connected with the positive power supply, and the drain of the second field effect transistor is connected with the negative power supply.

[0008] In a possible implementation, the overcurrent detection circuit further includes a first detection circuit, and the first detection circuit includes a second resistor and a first triode, the first end of the second resistor is connected with the gate of the first field effect transistor and the emitter of the first triode, and the second end of the second resistor is connected with the base of the first triode and the source of the first field effect transistor.

[0009] In a possible implementation, the first detection circuit further includes a first diode, a first resistor, a second diode, and a third diode, the anode of the first diode is connected with the second end of the first resistor, the anode of the second diode, the first end of the second resistor, and the anode of the third diode, the cathode of the first diode is connected with the drain of the first field effect transistor, the cathode of the third diode is connected with the first end of the first resistor and the gate of the first field effect transistor, and the cathode of the second diode is connected with the emitter of the first triode.

[0010] In a possible implementation, the first detection circuit further includes a fourth diode and a fourth resistor, the anode of the fourth diode is connected with the collector of the first triode, and the cathode of the fourth diode is connected with the first end of the fourth resistor.

[0011] In a possible implementation, the overcurrent detection circuit further includes a second detection circuit, and the second detection circuit includes a fifth diode, a second triode, and an eighth resistor, the cathode of the fifth diode is connected with the power amplifier output end, the anode of the fifth diode is connected with the base of the second triode, the first end of the eighth resistor, and the gate of the second field effect transistor, the emitter of the second triode is connected with the second end of the eighth resistor and the drain of the second triode.

[0012] In a possible implementation, the second detection circuit further includes a sixth resistor, a seventh resistor and an operational amplifier, a first end of the sixth resistor is connected with the collector of the second transistor, a second end of the sixth resistor is connected with a first end of the seventh resistor and an inverting input terminal of the operational amplifier, a second end of the seventh resistor is connected with a direct current power supply, and a non-inverting input terminal of the operational amplifier is grounded.

[0013] In a possible implementation, the second detection circuit further includes a fifth resistor, a sixth diode and a seventh diode, a first end of the fifth resistor is connected with the gate of the second field effect transistor and a cathode of the sixth diode, a second end of the fifth resistor is connected with an anode of the sixth diode and a first end of the eighth resistor, an anode of the seventh diode is connected with the emitter of the second transistor, and a cathode of the seventh diode is connected with a second end of the eighth resistor.

[0014] According to an aspect of the embodiment of the present application, a digital power amplifier device is provided, which includes a digital power amplifier circuit, a power amplifier protection circuit and the overcurrent detection circuit as described above, the overcurrent detection circuit is connected with the digital power amplifier circuit, and an output terminal of the overcurrent detection circuit is connected with the power amplifier protection circuit, the power amplifier protection circuit is used to trigger a power amplifier protection operation after receiving the power amplifier protection signal of the overcurrent detection circuit.

[0015] In a possible implementation, the digital power amplifier circuit further includes a first inductor and a first capacitor, a first end of the first inductor is connected with the source of the field effect transistor, a second end of the first inductor is connected with a power amplifier output terminal and a first end of the first capacitor, and a second end of the first capacitor is grounded.

[0016] The technical scheme provided by the embodiment of the present application has the following beneficial effects:

[0017] The overcurrent detection circuit provided by the present application includes an input terminal, a first detection terminal and a second detection terminal, the input terminal is connected with the gate of the field effect transistor, the first detection terminal is connected with the drain of the first field effect transistor, the second detection terminal is connected with the source of the first field effect transistor, and the first detection terminal is electrically connected with the input terminal, the overcurrent detection circuit is used to output a power amplifier protection signal when it is detected through the first detection terminal and the second detection terminal that the current through the field effect transistor exceeds a preset value, therefore, the overcurrent detection circuit of the embodiment of the present application can realize timely detection of overcurrent of the field effect transistor, effectively protect the digital power amplifier circuit, effectively reduce the possibility of damage of the digital power amplifier circuit, and prolong the service life of the digital power amplifier circuit. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced.

[0019] Fig. 1 is a structural diagram of an overcurrent detection circuit provided by the embodiments of the present application;

[0020] Fig. 2 is a specific structural diagram of an overcurrent detection circuit provided by the embodiments of the present application;

[0021] Fig. 3 is a circuit diagram of a digital power amplifier circuit provided by the embodiments of the present application;

[0022] Fig. 4 is a circuit diagram of an overcurrent detection circuit provided by the embodiments of the present application;

[0023] Fig. 5 is a structural diagram of a digital power amplifier device provided by the embodiments of the present application.

[0024] Brief description of the drawings: HO, first output end; LO, second output end; Q1, first field effect transistor; Q2, second field effect transistor; R2, second resistor; Q3, first triode; D1, first diode; R1, first resistor; D2, second diode; D3, third diode; D4, fourth diode; R4, fourth resistor; D5, fifth diode; Q4, second triode; R8, eighth resistor; R6, sixth resistor; R7, seventh resistor; U1A, operational amplifier; R5, fifth resistor; D6, sixth diode; D7, seventh diode; D8, eighth diode; L1, first inductor; C1, first capacitor. DETAILED DESCRIPTION

[0025] The embodiments of the present application will be described below in conjunction with the drawings in the present application. It should be understood that the embodiments described below in conjunction with the drawings are exemplary descriptions for explaining the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions of the embodiments of the present application.

[0026] It should be understood by those skilled in the art that, unless specifically stated, singular forms such as "one", "said" and "the" as used herein include plural forms. It should be further understood that the terms "comprise" and "include" used in the embodiments of the present application mean that the corresponding features can be implemented as the presented features, information, data, steps, operations, elements and / or components, but do not exclude other features, information, data, steps, operations, elements, components and / or their combinations supported by the present technology. It should be understood that when we say that an element is "connected" or "coupled" to another element, the element can be directly connected or coupled to the other element, or it can mean that the element and the other element establish a connection relationship through an intermediate element. In addition, "connection" or "coupling" used herein can include wireless connection or wireless coupling. The term "and / or" used herein indicates at least one of the items defined by the term, for example, "A and / or B" indicates implementation as "A", or implementation as "A", or implementation as "A and B".

[0027] For the purpose, technical solutions and advantages of the present application to be clearer, the embodiments of the present application will be further described in detail below with reference to the drawings.

[0028] The technical solutions of the embodiments of the present application and the technical effects produced by the technical solutions of the present application will be described below by describing several exemplary embodiments. It should be pointed out that the following embodiments can be mutually referenced, borrowed or combined, and the same terms, similar features and similar implementation steps in different embodiments will not be described repeatedly.

[0029] The overcurrent detection circuit and the digital power amplifier device provided by the present application aim to solve at least one technical problem existing in the prior art.

[0030] The embodiment of the present application provides a kind of overcurrent detection circuit, as shown in Figure 1-4, overcurrent detection circuit is connected with digital power amplifier circuit, digital power amplifier circuit includes pulse signal generation circuit, power amplifier output end and high level on field effect transistor, the gate of field effect transistor is connected with the output end of pulse signal generation circuit, source and power amplifier output end are connected, drain and power supply are connected;Overcurrent detection circuit includes input end, first detection end, second detection end, input end is connected with the gate of field effect transistor, first detection end is connected with the drain of field effect transistor, second detection end is connected with the source of field effect transistor, and first detection end and input end are electrically connected, overcurrent detection circuit is used to when detecting that the current through field effect transistor exceeds preset value by first detection end and second detection end, output power amplifier protection signal.Wherein, when the gate of field effect transistor is accessed high level, input end, first detection end, second detection end and field effect transistor form current loop, whether digital power amplifier circuit generates overcurrent is detected by detecting the current in the current loop.

[0031] Optionally, the preset value is determined based on the current value of the current through the field effect transistor when the digital power amplifier circuit generates overcurrent, and the digital power amplifier circuit is protected by outputting the power amplifier protection signal when the current exceeds the preset value.

[0032] Optionally, the pulse signal generation circuit includes a PWM modulation circuit and a gate drive circuit, which outputs a drive signal for driving the field effect transistor to turn on and off, thereby controlling the turn-on and turn-off of the field effect transistor to output the power amplified audio signal at the power amplifier output end.

[0033] Optionally, the output end of the digital power amplifier circuit includes a first output end HO and a second output end LO, the power supply includes a positive power supply and a negative power supply, the first output end HO and the second output end LO output high level in different time periods in the same pwm cycle, the field effect transistor includes a first field effect transistor Q1 and a second field effect transistor Q2, the gate of the first field effect transistor Q1 is connected with the first output end HO, the gate of the second field effect transistor Q2 is connected with the second output end LO, the drain of the first field effect transistor Q1 and the drain of the second field effect transistor Q2 are connected with the overcurrent detection circuit. Wherein, the drain of the first field effect transistor Q1 is connected with the positive power supply, and the drain of the second field effect transistor Q2 is connected with the negative power supply. The first field effect transistor Q1 serves as an upper half-bridge power amplifier tube of the digital power amplifier circuit, and the second field effect transistor Q2 serves as a lower half-bridge power amplifier tube of the digital power amplifier circuit, and the upper half-bridge power amplifier tube and the lower half-bridge power amplifier tube are turned on and off based on the level change of the first output end HO and the second output end LO.

[0034] Optionally, the overcurrent detection circuit further comprises a first detection circuit for overcurrent detection of the first field effect transistor Q1, the first detection circuit comprising a second resistor R2, a first triode Q3, a first end of the second resistor R2 being connected with a gate of the first field effect transistor Q1 and an emitter of the first triode Q3, a second end of the second resistor R2 being connected with a base of the first triode Q3 and a source of the first field effect transistor Q1, the first triode Q3 outputting a power amplifier protection signal through a collector thereof after being turned on. The resistance value of the second resistor R2 is determined according to the resistance value of the first field effect transistor Q1 after being turned on and the size of a preset value.

[0035] Optionally, the first detection circuit further comprises a first diode D1, a first resistor R1, a second diode D5 and a third diode D3, an anode of the first diode D1 being connected with a second end of the first resistor R1, an anode of the second diode D5, a first end of the second resistor R2 and an anode of the third diode D3, a cathode of the first diode D1 being connected with a drain of the first field effect transistor Q1, a cathode of the third diode D3 being connected with a first end of the first resistor R1 and a gate of the first field effect transistor Q1, a cathode of the second diode D5 being connected with an emitter of the first triode Q3.

[0036] Optionally, the first detection circuit further comprises a fourth diode D4 and a fourth resistor R4, an anode of the fourth diode D4 being connected with a collector of the first triode Q3, a cathode of the fourth diode D4 being connected with a first end of the fourth resistor R4. A second end of the fourth resistor R4 is connected with a signal receiving end, and the signal outputted by the collector of the first triode Q3 is transmitted to the signal receiving end after passing through the fourth diode D4 and the fourth resistor R4.

[0037] Optionally, the overcurrent detection circuit further comprises a second detection circuit for overcurrent detection of the second field effect transistor Q2, the second detection circuit comprising a fifth diode D5, a second triode Q4 and an eighth resistor R8, a cathode of the fifth diode D5 being connected with a power amplifier output end, an anode of the fifth diode D5 being connected with a base of the second triode Q4, a first end of the eighth resistor R8 and a gate of the second field effect transistor Q2, an emitter of the second triode Q4 being connected with a second end of the eighth resistor R8 and a drain of the second triode Q4.

[0038] Optionally, to ensure that the second detection circuit outputs the same power amplifier protection signal as the first detection circuit, the second detection circuit further comprises a sixth resistor R6, a seventh resistor R7 and an operational amplifier U1A, a first end of the sixth resistor R6 is connected with the collector of the second transistor Q4, a second end of the sixth resistor R6 is connected with a first end of the seventh resistor R7 and an inverting input terminal of the operational amplifier U1A, a second end of the seventh resistor R7 is connected with a direct current power supply, and a non-inverting input terminal of the operational amplifier U1A is grounded. An output terminal of the operational amplifier U1A is connected with a signal receiving terminal for receiving the power amplifier protection signal. When a voltage at the inverting input terminal of the operational amplifier U1A is lower than a voltage at the non-inverting input terminal, the output terminal of the operational amplifier U1A outputs a high level signal, and the high level signal is transmitted to the signal receiving terminal as the power amplifier protection signal.

[0039] Optionally, the second detection circuit further comprises a fifth resistor R5, a sixth diode D6 and a seventh diode D7, a first end of the fifth resistor R5 is connected with the gate of the second field effect transistor Q2 and a cathode of the sixth diode D6, a second end of the fifth resistor R5 is connected with an anode of the sixth diode D6 and a first end of an eighth resistor R8, an anode of the seventh diode D7 is connected with the emitter of the second transistor Q4, and a cathode of the seventh diode D7 is connected with a second end of the eighth resistor R8.

[0040] In one embodiment, the second detection circuit further comprises an eighth diode D8, an anode of the eighth diode D8 is connected with the output terminal of the operational amplifier U1A, and a cathode of the eighth diode D8 is connected with the output terminal of the first detection circuit.

[0041] The overcurrent detection circuit of the present application will be described below in combination with FIG. 3 and FIG. 4.

[0042] In one embodiment, the signal receiving end is port PROTECT, the first output end HO is connected with the gate of the first field effect transistor Q1, the first output end HO takes the pulse node as a reference point, the first output end HO outputs low level, the potential difference between the first output end HO and the pulse node is zero, the first field effect transistor Q1 is closed, the first diode D1 is reverse cut-off, the second resistor R2 has no potential difference between both ends, the first triode Q3 is closed, the circuit is not in action, the first output end HO outputs high level, the first field effect transistor Q1 is turned on, the first output end HO passes through the first resistor R1, the first diode D1, the source and the drain of the first field effect transistor Q1, and the second resistor R2 is connected with the first diode D1 and the first field effect transistor Q1, to form a path. When the first field effect transistor Q1 flows through a large current (the current exceeds a preset value), the turn-on voltage drop of the first field effect transistor Q1 rises, the second resistor R2 is connected with the first diode and the first field effect transistor Q1, the voltage between both ends of the second resistor R2 rises, the first triode Q3 is turned on, and the collector electrode outputs a power amplifier protection signal, which is transmitted to the port PROTCET through the fourth diode D4 and the fourth resistor R4, to start the power amplifier protection.

[0043] When the second output end LO outputs low level, the second output end LO takes the negative power supply as a reference point and is pulled low, the fifth diode D5 is reverse cut-off, the eighth resistor R8 has no potential difference between both ends, the second triode Q4 is closed, and the circuit is not in action. When the second output end LO outputs high level, the second field effect transistor Q2 is turned on, the current flows through the fifth resistor R5, the fifth diode D5, the source and the drain of the second field effect transistor Q2, and the fifth diode D5 is connected with the eighth resistor R8 and the source and the drain of the second field effect transistor Q2 in parallel. When the second field effect transistor Q2 flows through a large current, the voltage between both ends of the eighth resistor R8 rises, the second triode Q4 is turned on, the collector electrode voltage is pulled low, the voltage at the inverting input end of the operational amplifier U1A is lower than that at the non-inverting input end, the operational amplifier U1A outputs high level, and the high level is transmitted to the port PROTCET through the eighth diode D8, to start the power amplifier protection.

[0044] The overcurrent detection circuit of the present application synchronously detects the voltage drops of the first field effect transistor Q1 and the second field effect transistor Q2 when the first output end HO and the second output end LO output high level and low level, so that the overcurrent can be detected quickly cycle by cycle, the overcurrent detection circuit consumes less electric energy, the detection loss and the detection cost are low, and the cost of overcurrent protection is reduced.

[0045] According to an aspect of the embodiments of the present application, a digital power amplifier device is provided, as shown in FIGS. 1-5, which includes a digital power amplifier circuit, a power amplifier protection circuit, and an overcurrent detection circuit as described in the above embodiments. The overcurrent detection circuit is connected to the digital power amplifier circuit, and the output of the overcurrent detection circuit is connected to the power amplifier protection circuit. The power amplifier protection circuit is configured to trigger a power amplifier protection operation after receiving a power amplifier protection signal from the overcurrent detection circuit. The power amplifier protection circuit can be connected to at least one of the digital power amplifier circuit, a power supply of the digital power amplifier circuit, and a circuit configured to input an audio signal to the digital power amplifier circuit. The power amplifier protection circuit is configured to reduce the current in the digital power amplifier circuit or to shut down the digital power amplifier circuit.

[0046] Optionally, as shown in FIG. 3, the digital power amplifier circuit further includes a first inductor L1 and a first capacitor C1. The first end of the first inductor L1 is connected to the source of the field effect transistor. The second end of the first inductor L1 is connected to the power amplifier output and the first end of the first capacitor C1. The second end of the first capacitor C1 is connected to the ground. The first inductor L1 and the first capacitor C1 form an LC filter circuit.

[0047] The terms "first", "second", "third", "fourth", "1", "2", etc. (if any) in the description, claims, and drawings of the present application, and the above-described drawings, are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described.

[0048] It should be understood that, although the various operation steps in the flowcharts of the embodiments of the present application are indicated by arrows, the implementation order of these steps is not limited to the order indicated by the arrows. Unless otherwise specified herein, the implementation steps in each flowchart can be performed in other orders in some implementation scenarios of the embodiments of the present application. In addition, part or all of the steps in each flowchart can include multiple sub-steps or multiple stages based on the actual implementation scenario. Part or all of these sub-steps or stages can be executed at the same time, and each of these sub-steps or stages can also be executed at different times. In scenarios where the execution times are different, the execution order of these sub-steps or stages can be flexibly configured as required, and the embodiments of the present application do not limit this.

[0049] The above description is only an optional implementation of some implementation scenarios of the present application. It should be pointed out that, for those skilled in the art, other similar implementation manners based on the technical concept of the present application can also be adopted without departing from the technical concept of the present application, and these also belong to the protection scope of the embodiments of the present application.

Claims

1. An overcurrent detection circuit, characterized by comprising: The overcurrent detection circuit is connected with a digital power amplifier circuit, the digital power amplifier circuit comprises a pulse signal generation circuit and a high-level on field effect transistor, an output end of the pulse signal generation circuit comprises a first output end and a second output end, time segments of the first output end and the second output end outputting high level are different in a same pwm period, the field effect transistor comprises a first field effect transistor and a second field effect transistor, a gate of the first field effect transistor is connected with the first output end, a gate of the second field effect transistor is connected with the second output end, a source of the first field effect transistor and a drain of the second field effect transistor are connected with the overcurrent detection circuit and a power amplifier output end, a drain of the first field effect transistor is connected with a positive power supply in a power supply, and a source of the second field effect transistor is connected with a negative power supply in the power supply. The overcurrent detection circuit comprises an input end, a first detection end and a second detection end, the input end is connected with the gate of the field effect transistor, the first detection end is connected with the drain of the field effect transistor, the second detection end is connected with the source of the field effect transistor, and the first detection end is electrically connected with the input end, the overcurrent detection circuit is used for outputting a power amplifier protection signal when it is detected through the first detection end and the second detection end that the current through the field effect transistor exceeds a preset value.

2. The overcurrent detection circuit of claim 1, wherein The overcurrent detection circuit further comprises a first detection circuit, the first detection circuit comprises a second resistor and a first triode, a first end of the second resistor is connected with the gate of the first field effect transistor and an emitter of the first triode, and a second end of the second resistor is connected with a base of the first triode and the source of the first field effect transistor.

3. The overcurrent detection circuit of claim 2, wherein, The first detection circuit further comprises a first diode, a first resistor, a second diode and a third diode, an anode of the first diode is connected with a second end of the first resistor, an anode of the second diode, a first end of the second resistor, and an anode of the third diode, a cathode of the first diode is connected with the drain of the first field effect transistor, a cathode of the third diode is connected with a first end of the first resistor and the gate of the first field effect transistor, and a cathode of the second diode is connected with the emitter of the first triode.

4. The overcurrent detection circuit of claim 2, wherein, The first detection circuit further comprises a fourth diode and a fourth resistor, an anode of the fourth diode is connected with a collector of the first triode, and a cathode of the fourth diode is connected with a first end of the fourth resistor.

5. The overcurrent detection circuit of claim 1, wherein, The overcurrent detection circuit further comprises a second detection circuit, the second detection circuit comprises a fifth diode, a second triode and an eighth resistor, a cathode of the fifth diode is connected with the power amplifier output end, an anode is connected with a base of the second triode, a first end of the eighth resistor and a gate of the second field effect transistor, an emitter of the second triode is connected with a second end of the eighth resistor and a source of the second field effect transistor.

6. The overcurrent detection circuit of claim 5, wherein, The second detection circuit further comprises a sixth resistor, a seventh resistor and an operational amplifier, a first end of the sixth resistor is connected with the collector of the second transistor, a second end of the sixth resistor is connected with the first end of the seventh resistor and the inverting input terminal of the operational amplifier, a second end of the seventh resistor is connected with a direct current power supply, and the non-inverting input terminal of the operational amplifier is grounded.

7. The overcurrent detection circuit of claim 5, wherein, The second detection circuit further comprises a fifth resistor, a sixth diode and a seventh diode, a first end of the fifth resistor is connected with the gate of the second field effect transistor and the cathode of the sixth diode, a second end of the fifth resistor is connected with the anode of the sixth diode and the first end of the eighth resistor, the anode of the seventh diode is connected with the emitter of the second transistor, and the cathode of the seventh diode is connected with the second end of the eighth resistor.

8. A digital power amplifier device, characterized by, The digital power amplifier device comprises a digital power amplifier circuit, a power amplifier protection circuit and the overcurrent detection circuit according to any one of claims 1-7, the overcurrent detection circuit is connected with the digital power amplifier circuit, and the output end of the overcurrent detection circuit is connected with the power amplifier protection circuit, the power amplifier protection circuit is used for triggering a power amplifier protection operation after receiving a power amplifier protection signal from the overcurrent detection circuit.

9. The digital power amplifier device of claim 8, wherein, The digital power amplifier circuit further comprises a first inductor and a first capacitor, a first end of the first inductor is connected with the source of the field effect transistor, a second end of the first inductor is connected with a power amplifier output end and a first end of the first capacitor, and a second end of the first capacitor is grounded.

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