Small power amplifier sound switching power supply with high power density

Abstract

The invention discloses a small-sized power amplifier sound switching power supply with high power density. The small-sized power amplifier sound switching power supply comprises an input rectification filtering module, a main control module, a PFC module, an LLC power conversion module, a synchronous rectification module, a standby power supply module and a feedback module, the input end of the input rectification filtering module and the input end of the standby power supply module are connected with an external power supply; the output end of the standby power supply module is connected with the main control module; the PFC module is respectively connected with the output end of the input rectification filtering module, the input end of the LLC power conversion module and the main control module; the synchronous rectification module is connected between the output end of the LLC power conversion module and a load; the feedback module is connected among the output end of the synchronous rectification module, the standby power supply module and the main control module; by means of the circuit, standby power consumption can be greatly reduced, the requirement that the standby power is smaller than 0.5 W in European Union is met, high power can be output, and stable work can be achieved at low power.

Description

Technical Field

[0001] The invention relates to the field of audio switching power supplies, and in particular to a small-sized power amplifier audio switching power supply with high power density. Background Art

[0002] With the development of science and technology and the improvement of people's living standards, medium and high power audio equipment has become an indispensable part of people's daily life. The power amplifier in the audio equipment is its core part, and its performance directly affects the sound quality and power of the audio equipment.

[0003] At present, medium and high power amplifier audio switching power supplies on the market generally have the problems of large size and high power consumption, which is not conducive to the miniaturization and energy saving of audio equipment; since the LLC architecture switching power supply has the advantages of constant output power and small impact on the switching power supply, it is suitable for TV power supply, LED lighting and other power supplies, but if the LLC architecture switching power supply is used on audio, there are some problems, such as high temperature. Although the components of the switching power supply have the advantage of high temperature resistance, the high-power mini audio boxes are relatively small and have narrow internal space. If the LLC architecture switching power supply is directly used on the audio, the components will conduct heat to the machine casing, and the human body will easily cause harm to the operator when it touches the machine casing; therefore, a small amplifier audio switching power supply with high power density is urgently needed to solve the above problems. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a small power amplifier audio switching power supply with high power density.

[0005] The technical solution adopted by an embodiment of the present invention to solve the technical problem is: a small power amplifier audio switching power supply with high power density, including an input rectification and filtering module, a main control module, a PFC module, an LLC power conversion module, a synchronous rectification module, a standby power module and a feedback module;

[0006] The input end of the input rectifier filter module and the input end of the standby power module are connected to an external power supply;

[0007] The output end of the standby power module is connected to the main control module;

[0008] The PFC module is respectively connected to the output end of the input rectifier filter module, the input end of the LLC power conversion module and the main control module;

[0009] The synchronous rectification module is connected between the output end of the LLC power conversion module and the load;

[0010] The feedback module is connected between the output end of the synchronous rectification module, the standby power module and the main control module;

[0011] Also included is an output filter module connected between the synchronous rectification module and the load;

[0012] When powered on, the standby power module first supplies power to the main control module, and then the main control module controls the LLC power conversion module to supply power to the load.

[0013] As one of the preferred embodiments of the present invention, the input rectifier filter module includes a fuse F1, an inductor LF3, an inductor LF4, a capacitor XC1, a capacitor XC2, a rectifier bridge BD1, a capacitor C5, a resistor R19 and a resistor R24, the fuse F1 is connected between one end of the external power supply and the fourth end of the inductor LF4, the third end of the inductor LF4 is connected to the other end of the external power supply, the second end of the inductor LF4 is respectively connected to one end of the capacitor XC2 and the second end of the inductor LF3, and the first end of the inductor LF4 is respectively connected to the other end of the capacitor XC2. And the fourth end of the inductor LF3, the first end of the inductor LF3 is respectively connected to one end of the capacitor XC1 and the second end of the rectifier bridge BD1, the third end of the inductor LF3 is respectively connected to the other end of the capacitor XC1 and the third end of the rectifier bridge BD1, the first end of the rectifier bridge BD1 is respectively connected to one end of the capacitor C5 and the PFC module, the fourth end of the rectifier bridge BD1 is respectively connected to the other end of the capacitor C5, one end of the resistor R19, one end of the resistor R24 ​​and the main control module, and the other end of the resistor R19 and the other end of the resistor R24 ​​are grounded.

[0014] As one of the preferred embodiments of the present invention, the PFC module includes a gallium nitride switch device Q3, an inductor L3, a diode D4-D6, a resistor RT1, a resistor R21-R22, a resistor R25, a resistor R29-R30, a resistor R38, a capacitor C6, a capacitor EC5 and a capacitor EC6, one end of the inductor L3 is respectively connected to the input rectifier filter module and the anode of the diode D4, the other end of the inductor L3 is respectively connected to the anode of the diode D5 and the input end of the gallium nitride switch device Q3, the cathode of the diode D4 is respectively connected to the cathode of the diode D5 and one end of the resistor RT1, the control end of the gallium nitride switch device Q3 is respectively connected to the anode of the diode D6, one end of the resistor R28 and one end of the resistor R30, the cathode of the diode D6 is connected to the other end of the resistor R28 and is connected to the main control module via the resistor R22, the output end of the gallium nitride switch device Q3 is respectively connected to the other end of the resistor R30, one end of the resistor EC5 and one end of the capacitor EC6, the other end of the capacitor EC5 is respectively connected to the other end of the capacitor EC6, the resistor RT 1, one end of capacitor C6, one end of resistor R21 and LLC power conversion module are connected, and the other end of resistor R21 is connected to the other end of capacitor C6 and connected to the main control module via resistor R25 and resistor R29.

[0015] As one of the preferred embodiments of the present invention, the LLC power conversion module includes a first drive circuit, a second drive circuit, a gallium nitride switch device Q5, a gallium nitride switch device Q6, an inductor T4, a transformer T3 and a capacitor C19. The first drive circuit is connected between the main control module and the control end of the gallium nitride switch device Q5, the second drive circuit is connected between the main control module and the control end of the gallium nitride switch device Q6, the input end of the gallium nitride switch device Q5 is connected to VBUS, the output end of the gallium nitride switch device Q5 is respectively connected to the input end of the gallium nitride switch device Q6 and one end of the inductor T4, the other end of the inductor T4 is connected to one end of the primary winding of the transformer T3, the other end of the primary winding of the transformer T3 is respectively connected to the main control module and one end of the capacitor C19, the other end of the capacitor C19 is grounded, and the secondary winding of the transformer T3 is connected to the synchronous rectification module.

[0016] As one of the preferred embodiments of the present invention, the first driving circuit includes a resistor R27, a resistor R32, a resistor R33 and a diode D7, one end of the resistor 27 is respectively connected to the main control module and one end of the resistor R32, the other end of the resistor R32 is respectively connected to the other end of the diode R27, one end of the resistor R33 and the control end of the gallium nitride switch device Q5 through the diode D7, and the other end of the resistor R33 is connected to the output end of the gallium nitride switch device Q5.

[0017] As one of the preferred embodiments of the present invention, the second driving circuit includes a resistor R35, a resistor R37, a resistor R40 and a diode D9, one end of the resistor R35 is respectively connected to the main control module and one end of the resistor R37, the other end of the resistor R37 is respectively connected to the other end of the diode R35, one end of the resistor R40 and the control end of the gallium nitride switch device Q6 through the diode D9, and the other end of the resistor R40 is connected to the output end of the gallium nitride switch device Q6.

[0018] As one of the preferred embodiments of the present invention, the synchronous rectification module includes a synchronous rectification chip U8, a MOS tube Q4, a MOS tube Q7, a resistor R26, a resistor R34, a resistor R36, a resistor R41 and a capacitor C8-C11, the drain of the MOS tube Q4 is respectively connected to the LLC power conversion module and one end of the resistor R36, the gate of the MOS tube Q4 is connected to the VG2 end of the synchronous rectification chip U8, the drain of the MOS tube Q7 is respectively connected to the LLC power conversion module and one end of the resistor R41, the gate of the MOS tube Q7 is connected to the VG2 end of the synchronous rectification chip U8 1 end is connected, the source of the MOS tube Q4 and the source of the MOS tube Q7 are connected to the AGND end, the capacitor C9 and the resistor R34 are connected in parallel between the LL end and the PGND end of the synchronous rectifier chip U8, the other end of the resistor R36 is connected to the VD2 end of the synchronous rectifier chip U8 and is respectively connected to the VSS end of the synchronous rectifier chip U8 and one end of the capacitor C11 through the capacitor C10, the other end of the capacitor C11 is respectively connected to one end of the resistor R41 and the VD1 end of the synchronous rectifier chip U8, one end of the resistor R26 is connected to the power supply, and the other end is respectively connected to the VDD end of the synchronous rectifier chip U8 and one end of the capacitor C8, and the other end of the capacitor C8 is connected to the AGND end.

[0019] As one of the preferred embodiments of the present invention, the feedback module includes an optocoupler U4, an optocoupler U6, a transistor Q10-Q11, a voltage regulator U7, a voltage regulator diode ZD1-ZD2, resistors R6-R7, a resistor R11, a resistor R14-R15, a resistor R17-R18, a resistor R20, a resistor R23, a resistor R31 and a capacitor C7, one end of the resistor R6 is connected to the standby power module, the other end of the resistor R6 is respectively connected to the base of the transistor Q10, the collector of the transistor Q11 and one end of the resistor R15, the emitter of the transistor Q10 is respectively connected to one end of the optocoupler U4 light emitter and one end of the resistor R11, the other end of the optocoupler U4 light emitter is connected to the other end of the resistor R11 and connected to the power supply through the resistor R7, the other end of the resistor R15 is respectively connected to the emitter of the transistor Q10 and the emitter of the transistor Q11, the base of the transistor Q11 is connected to the resistor R14, the voltage regulator diode ZD 1. The voltage regulator diode ZD2 is respectively connected to one end of the resistor R18 and one end of the capacitor C7, the other end of the resistor R18 is connected to one end of the capacitor C7 and the resistor R23 is respectively connected to one end of the resistor R31 and the control end of the voltage regulator U7, the other end of the resistor R31 is respectively connected to the input end and the ground end of the voltage regulator U7, the output end of the voltage regulator U7 is respectively connected to one end of the light emitter of the optocoupler U6 and one end of the resistor R20, the other end of the light emitter of the optocoupler U6 is connected to the other end of the resistor R20 and connected to the power supply through the resistor R17, and the light receiver of the optocoupler U4 and the light receiver of the optocoupler U6 are connected to the main control module.

[0020] The invention has the following beneficial effects: a small power amplifier audio switching power supply with high power density, comprising an input rectifier filter module, a main control module, a PFC module, an LLC power conversion module, a synchronous rectifier module, a standby power module and a feedback module; the input end of the input rectifier filter module and the input end of the standby power module are connected to an external power supply; the output end of the standby power module is connected to the main control module; the PFC module is respectively connected to the output end of the input rectifier filter module, the input end of the LLC power conversion module and the main control module; the synchronous rectifier module is connected between the output end of the LLC power conversion module and the load; the feedback module is connected between the output end of the synchronous rectifier module, the standby power module and the main control module; and also includes an output filter module connected between the synchronous rectifier module and the load; when powered on, the standby power module first supplies power to the main control module, and then the main control module controls the LLC power conversion module to supply power to the load; the above circuit can greatly reduce the standby power consumption, meet the EU standby requirement of less than 0.5W, and can output high power and work stably at low power. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 The circuit diagram of a small power amplifier audio switching power supply with high power density;

[0023] Figure 2 This is the circuit schematic diagram of the input rectifier and filter module;

[0024] Figure 3 This is the circuit schematic diagram of the main control module;

[0025] Figure 4 This is the circuit schematic diagram of the PFC module;

[0026] Figure 5 It is the circuit schematic diagram of LLC power conversion module;

[0027] Figure 6 It is the circuit schematic diagram of the synchronous rectification module;

[0028] Figure 7 This is the circuit schematic diagram of the standby power module;

[0029] Figure 8 This is the first part of the circuit schematic diagram of the standby power module;

[0030] Fig. 9 This is the schematic diagram of the second part of the circuit of the standby power module;

[0031] Fig.10 This is the third circuit schematic diagram of the standby power module;

[0032] Fig.11 It is the circuit schematic diagram of the feedback module;

[0033] Fig.12 This is the circuit schematic diagram of the output filter module. DETAILED DESCRIPTION

[0034] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0035] In the description of the present invention, the meaning of "above", "below", "exceed", etc. is not inclusive of the number itself, and the meaning of "above", "below", "within", etc. is inclusive of the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0036] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0037] In the present invention, unless otherwise clearly defined, the words "set", "install", "connect" and the like should be understood in a broad sense, for example, they can be directly connected or indirectly connected through an intermediate medium; they can be fixedly connected or detachably connected or integrally formed; they can be mechanically connected; they can be the internal connection of two elements or the interaction relationship between two elements. Those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

[0038] Reference Figures 1 to 12 , a small power amplifier audio switching power supply with high power density, including an input rectification and filtering module 10, a main control module 20, a PFC module 30, an LLC power conversion module 40, a synchronous rectification module 50, a standby power module 60 and a feedback module 70;

[0039] The input end of the input rectifier filter module 10 and the input end of the standby power module 60 are connected to an external power source;

[0040] The output end of the standby power module 60 is connected to the main control module 20;

[0041] The PFC module 30 is respectively connected to the output end of the input rectification and filtering module 10, the input end of the LLC power conversion module 40 and the main control module 20;

[0042] The synchronous rectification module 50 is connected between the output end of the LLC power conversion module 40 and the load;

[0043] The feedback module 70 is connected between the output end of the synchronous rectification module 50, the standby power module 60 and the main control module 20;

[0044] When powered on, the standby power module 60 first supplies power to the main control module 20 , and then the main control module 20 controls the LLC power conversion module 40 to supply power to the load.

[0045] In the present invention, the working principle is as follows:

[0046] 1)Reference Figure 1-Figure 2In some embodiments, the input rectifier filter module 10 includes a fuse F1, an inductor LF3, an inductor LF4, a capacitor XC1, a capacitor XC2, a rectifier bridge BD1, a capacitor C5, a resistor R19, and a resistor R24. The fuse F1 is connected between one end of the external power supply and the fourth end of the inductor LF4, the third end of the inductor LF4 is connected to the other end of the external power supply, the second end of the inductor LF4 is respectively connected to one end of the capacitor XC2 and the second end of the inductor LF3, the first end of the inductor LF4 is respectively connected to the other end of the capacitor XC2 and the inductor The fourth end of LF3 is connected, the first end of the inductor LF3 is respectively connected to one end of the capacitor XC1 and the second end of the rectifier bridge BD1, the third end of the inductor LF3 is respectively connected to the other end of the capacitor XC1 and the third end of the rectifier bridge BD1, the first end of the rectifier bridge BD1 is respectively connected to one end of the capacitor C5 and the PFC module 30, the fourth end of the rectifier bridge BD1 is respectively connected to the other end of the capacitor C5, one end of the resistor R19, one end of the resistor R24 ​​and the main control module 20, and the other end of the resistor R19 and the other end of the resistor R24 ​​are grounded.

[0047] Specifically, CON 1 is the AC power input, which passes through the fuse F1 and the filter (inductor LF3 and inductor LF4) and the X capacitor (capacitor XC1 and capacitor XC2) and enters the rectifier bridge BD1 for rectification, and the AC power is converted into a DC power. The capacitor C5 is a DC filter capacitor, and the resistor R19 and the resistor 24 are current limiting resistors, which are used to detect the current and play a protective role when the current exceeds the limit.

[0048] 2)Reference Figure 1 and Figure 4In some embodiments, the PFC module 30 includes a gallium nitride switch device Q3, an inductor L3, diodes D4-D6, a resistor RT1, resistors R21-R22, a resistor R25, resistors R29-R30, a resistor R38, a capacitor C6, a capacitor EC5 and a capacitor EC6, one end of the inductor L3 is respectively connected to the input rectifier filter module 10 and the anode of the diode D4, the other end of the inductor L3 is respectively connected to the anode of the diode D5 and the input end of the gallium nitride switch device Q3, the cathode of the diode D4 is respectively connected to the cathode of the diode D5 and the resistor RT 1, the control end of the gallium nitride switch device Q3 is respectively connected to the anode of the diode D6, one end of the resistor R28 and one end of the resistor R30, the cathode of the diode D6 is connected to the other end of the resistor R28 and is connected to the main control module 20 via the resistor R22, the output end of the gallium nitride switch device Q3 is respectively connected to the other end of the resistor R30, one end of the resistor EC5 and one end of the capacitor EC6, the other end of the capacitor EC5 is respectively connected to the other end of the capacitor EC6, the other end of the resistor RT1, one end of the capacitor C6, one end of the resistor R21 and the LLC power conversion module 40, the other end of the resistor R21 is connected to the other end of the capacitor C6 and is connected to the main control module 20 via the resistor R25 and the resistor R29.

[0049] Specifically, the diode D4 and the resistor RT1 pre-charge the capacitors EC5 and EC6 to reduce the instantaneous charging current impact of the PFC circuit part; the inductor L3 is the PFC inductor, and the diode D5 is the PFC rectifier diode. When the gallium nitride switch device Q3 is working, the diode D5 rectifies and outputs a 380-400V voltage to charge the capacitors EC5 and EC6. After being fully charged, the voltage on the capacitors EC5 and EC6 reaches 380V-400V, which is provided to the subsequent LLC power conversion module 40 for power supply; the resistors R21, R25, R29 and R38 form a voltage divider circuit, and the voltage after voltage division is provided to the control chip U9 in the main control module 30 for voltage detection to determine that the output voltage cannot exceed 400V.

[0050] 3)Reference Figure 1 and Figure 5In some embodiments, the LLC power conversion module 40 includes a first drive circuit 41, a second drive circuit 42, a gallium nitride switch device Q5, a gallium nitride switch device Q6, an inductor T4, a transformer T3 and a capacitor C19. The first drive circuit 41 is connected between the main control module 20 and the control end of the gallium nitride switch device Q5, the second drive circuit 42 is connected between the main control module 20 and the control end of the gallium nitride switch device Q6, the input end of the gallium nitride switch device Q5 is connected to VBUS, the output end of the gallium nitride switch device Q5 is respectively connected to the input end of the gallium nitride switch device Q6 and one end of the inductor T4, the other end of the inductor T4 is connected to one end of the primary winding of the transformer T3, the other end of the primary winding of the transformer T3 is respectively connected to the main control module 20 and one end of the capacitor C19, the other end of the capacitor C19 is grounded, and the secondary winding of the transformer T3 is connected to the synchronous rectification module 50.

[0051] Specifically, the gallium nitride switch device Q5, the gallium nitride switch device Q6, the inductor T4, the capacitor C19 and the transformer T3 form an LLC half-bridge resonant circuit, and the 7th and 12th pins of the control chip U9 in the main control module 30 output PWM to the G poles of the gallium nitride switch device Q5 and the gallium nitride switch device Q6 to control the conduction and cutoff of the gallium nitride switch device Q5 and the gallium nitride switch device Q6, wherein the gallium nitride switch device Q5 is the upper half bridge, the gallium nitride switch device Q6 is the lower half bridge, and the MOS tubes Q4 and M on the secondary side of the transformer T3 are connected to the MOS tubes Q5 and Q6. The OS tube Q7 is a synchronous rectification MOS tube, and a stable DC power output is obtained after full-wave rectification of the MOS tubes Q4 and Q7; the gallium nitride switch device Q5 and the gallium nitride switch device Q6 of the LLC power conversion module 40 both adopt ultra-clean MOS with low internal resistance. Since the diode inside the ultra-clean MOS is quickly closed, the delayed conduction problem during the crossover between the upper tube and the lower tube can be effectively reduced, the switching speed can be increased, and the area of ​​the transformer can be reduced, thereby effectively reducing the heat generation, reducing the area of ​​the radiator, and reducing the volume of the power board.

[0052] In a further embodiment, the first driving circuit 41 includes a resistor R27, a resistor R32, a resistor R33 and a diode D7, one end of the resistor 27 is respectively connected to the main control module 20 and one end of the resistor R32, the other end of the resistor R32 is respectively connected to the other end of the diode R27, one end of the resistor R33 and the control end of the gallium nitride switch device Q5 through the diode D7, and the other end of the resistor R33 is connected to the output end of the gallium nitride switch device Q5; the second driving circuit 42 includes a resistor R35, a resistor R37, a resistor R40 and a diode D9, one end of the resistor R35 is respectively connected to the main control module 20 and one end of the resistor R37, the other end of the resistor R37 is respectively connected to the other end of the diode R35, one end of the resistor R40 and the control end of the gallium nitride switch device Q6 through the diode D9, and the other end of the resistor R40 is connected to the output end of the gallium nitride switch device Q6.

[0053] 4)Reference Figure 1 and Figure 5 In some embodiments, the synchronous rectification module 50 includes a synchronous rectification chip U8, a MOS tube Q4, a MOS tube Q7, a resistor R26, a resistor R34, a resistor R36, a resistor R41 and capacitors C8-C11, the drain of the MOS tube Q4 is connected to the LLC power conversion module 40 and one end of the resistor R36, the gate of the MOS tube Q4 is connected to the VG2 end of the synchronous rectification chip U8, the drain of the MOS tube Q7 is connected to the LLC power conversion module 40 and one end of the resistor R41, the gate of the MOS tube Q7 is connected to the VG2 end of the synchronous rectification chip U8 1 end is connected, the source of the MOS tube Q4 and the source of the MOS tube Q7 are connected to the AGND end, the capacitor C9 and the resistor R34 are connected in parallel between the LL end and the PGND end of the synchronous rectifier chip U8, the other end of the resistor R36 is connected to the VD2 end of the synchronous rectifier chip U8 and is respectively connected to the VSS end of the synchronous rectifier chip U8 and one end of the capacitor C11 through the capacitor C10, the other end of the capacitor C11 is respectively connected to one end of the resistor R41 and the VD1 end of the synchronous rectifier chip U8, one end of the resistor R26 is connected to the power supply, and the other end is respectively connected to the VDD end of the synchronous rectifier chip U8 and one end of the capacitor C8, and the other end of the capacitor C8 is connected to the AGND end.

[0054] Specifically, the control chip U8 is a synchronous rectification control chip, which is used to control the conduction and cutoff of MOS tubes Q4 and Q7. The rectified DC power supply is filtered by the output filter module 80 composed of capacitors C12-C13, capacitors EC7-EC9 and inductor LF2 and provided to the load; the secondary output of transformer T3 adopts a synchronous rectification circuit, and the secondary circuit is used for the synchronous rectification control circuit. The synchronous tubes MOS tubes Q4 and Q7 adopt ultra-internal resistance MOS to reduce the heat caused by the internal resistance of the circuit, reduce the loss of the power supply, and reduce the heat generation. Since the secondary MOS has only a few milliohms, no heat sink is required, and the power board can not only reduce the volume, but also reduce the power ripple.

[0055] 5)Reference Figure 1 , Figure 7-10 Preferably, the standby power supply module 60 includes a pre-stage filter circuit, a transformer T1, a feedback circuit and a control circuit. The pre-stage filter circuit is respectively connected to the external power supply, the primary winding of the transformer T1 and the input end of the feedback circuit. The output end of the feedback circuit is connected to the control circuit. The control circuit is connected between the main control module 20 and the secondary winding of the transformer T1. It can convert the external power supply and provide it to the main control module 20 when powered on. When the main control module 20 receives a power-on command, it controls the LLC power conversion module 40 to supply power to the load.

[0056] Specifically, the pre-stage filter circuit includes an inductor LF1, capacitors EC2-EC3, capacitor C3 and a chip U1. The first end and the second end of the inductor LF1 are connected to an external power supply, the third end of the inductor LF1 is respectively connected to one end of the capacitor EC2, one end of the capacitor EC3 and one end of the primary winding of the transformer T1, the fourth end of the inductor LF1 is respectively connected to the other end of the capacitor EC2, the other end of the capacitor EC3, one end of the capacitor C3 and pin 2, pin 3 and pin 4 of the chip U1, the other end of the capacitor C3 is connected to pin 1 of the chip U1, and the other end of the primary winding of the transformer T1 is connected to pin 5, pin 6, pin 7 and pin 8 of the chip U1.

[0057] The feedback circuit includes resistors R8-R9, resistor R13, resistor R16, optocoupler U3 and voltage regulator U5. One end of resistor R9 is respectively connected to one end of resistor R8 and a 12V power supply, the other end of resistor R9 is respectively connected to one end of resistor R16 and a control end of voltage regulator U5, the other end of resistor R16 is respectively connected to an input end and a ground end of voltage regulator U5, the output end of voltage regulator U5 is respectively connected to one end of the light emitter of optocoupler U3 and one end of resistor R13, the other end of the light emitter of optocoupler U3 is respectively connected to the other end of resistor R13 and the other end of resistor R8, and the two ends of the light receiver of optocoupler U3 are connected to the control circuit for feedback of input signals.

[0058] The control circuit includes a control chip U2, resistors R1-R5, resistor R10, resistor R12, diodes D1-D3, capacitors EC1, capacitor EC4, capacitors C1-C4 and inductor L1. One end of the inductor L1 is connected to VBUS, and the other end of the inductor L1 is respectively connected to one end of the resistor R1, one end of the capacitor EC1, one end of the resistor R2, one end of the capacitor C1 and one end of the secondary winding of the transformer T1. The other end of the resistor R1 is respectively connected to one end of the capacitor C2, the cathode of the diode D3 and the VDD end of the control chip U2 through the resistor R3. The anode of the diode D3 is respectively connected to the AUX18V end, the capacitor EC1, the cathode of the diode D3 and the VDD end of the control chip U2. 4 and the cathode of diode D2, the anode of diode D2 is connected to the AUXVCC terminal, one end of resistor R5 is connected to the AUXVCC terminal, and the other end is respectively connected to the DEM terminal of control chip U2 and one end of resistor R10, the other end of resistor R10 is respectively connected to the other end of capacitor EC4, one end of optocoupler U3 light receiver, one end of resistor R12, one end of capacitor C4 and the ground terminal, the other end of optocoupler U3 light receiver is connected to the FB terminal of control chip U2, the other end of resistor R12 is connected to the Sense terminal of control chip U2, the other end of capacitor C4 is respectively connected to the Dr ain terminal of control chip U2, the anode of diode D1 and the other end of secondary winding of transformer T1, the cathode of diode D1 is respectively connected to the other end of resistor R2 and the other end of capacitor C1 through resistor R4, the other end of capacitor EC1 and the other end of capacitor C2 are grounded.

[0059] 6)Reference Figure 1 , Fig.11Preferably, the feedback module 70 includes an optocoupler U4, an optocoupler U6, transistors Q10-Q11, a voltage regulator U7, a voltage regulator diode ZD1-ZD2, resistors R6-R7, a resistor R11, a resistor R14-R15, a resistor R17-R18, a resistor R20, a resistor R23, a resistor R31 and a capacitor C7, one end of the resistor R6 is connected to the standby power module 60, the other end of the resistor R6 is respectively connected to the base of the transistor Q10, the collector of the transistor Q11 and one end of the resistor R15, the emitter of the transistor Q10 is respectively connected to one end of the optocoupler U4 light emitter and one end of the resistor R11, the other end of the optocoupler U4 light emitter is connected to the other end of the resistor R11 and is connected to the power supply through the resistor R7, and the other end of the resistor R15 is respectively connected to The emitter of transistor Q10 is connected to the emitter of transistor Q11, the base of transistor Q11 is connected to one end of resistor R18 and one end of capacitor C7 respectively via resistor R14, voltage zener diode ZD1 and voltage zener diode ZD2, the other end of resistor R18 is connected to one end of capacitor C7 and resistor R23 is connected to one end of resistor R31 and the control end of voltage stabilizer U7 respectively, the other end of resistor R31 is connected to the input end and the ground end of voltage stabilizer U7 respectively, the output end of voltage stabilizer U7 is connected to one end of the light emitter of optocoupler U6 and one end of resistor R20 respectively, the other end of the light emitter of optocoupler U6 is connected to the other end of resistor R20 and connected to the power supply via resistor R17, the light receiver of optocoupler U4 and the light receiver of optocoupler U6 are connected to the main control module 20.

[0060] Specifically, diode ZD1, diode ZD2, diode D6, transistor Q10 and transistor Q11 constitute an overvoltage protection circuit, and resistor R6 and resistor R7 constitute an overcurrent protection circuit; the overall circuit feeds back electrical parameters to the main control module 20 to achieve stable control of the output.

[0061] 7) The advantages of the present invention are: by optimizing the circuit design, a small-volume and high-power-density power amplifier audio switching power supply is realized, which can effectively reduce the size of the board and reduce the heat generation. It is beneficial to the portability and energy saving of audio equipment; it adopts a streamlined input filter circuit and a reasonable component layout. It reduces electromagnetic interference, can effectively eliminate high-frequency interference in the input voltage, and improves the output efficiency of the switching power supply; current, voltage, temperature, and protection circuits are set to effectively protect the switching power supply from abnormal conditions and improve the safety of the switching power supply; the above circuit can greatly reduce the standby power consumption, meet the EU standby requirement of less than 0.5W, and can output high power and work stably at low power.

[0062] Of course, the present invention is not limited to the above-mentioned embodiments, and those skilled in the art may make equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications and substitutions are all included in the scope defined by the claims of this application.

Claims

1. A small power amplifier audio switching power supply with high power density, characterized in that: It comprises an input rectification and filtering module (10), a main control module (20), a PFC module (30), an LLC power conversion module (40), a synchronous rectification module (50), a standby power supply module (60) and a feedback module (70); The input end of the input rectifying and filtering module (10) and the input end of the standby power supply module (60) are connected to an external power supply; The output end of the standby power module (60) is connected to the main control module (20); The PFC module (30) is respectively connected to the output end of the input rectification and filtering module (10), the input end of the LLC power conversion module (40), and the main control module (20); The synchronous rectification module (50) is connected between the output end of the LLC power conversion module (40) and a load; The feedback module (70) is connected between the output end of the synchronous rectification module (50), the standby power module (60) and the main control module (20); It also includes an output filter module (80) connected between the synchronous rectification module (50) and the load; When powered on, the standby power module (60) first supplies power to the main control module (20), and then the main control module (20) controls the LLC power conversion module (40) to supply power to the load.

2. According to claim 1, a small power amplifier audio switching power supply with high power density, characterized in that: The input rectifier filter module (10) comprises a fuse F1, an inductor LF3, an inductor LF4, a capacitor XC1, a capacitor XC2, a rectifier bridge BD1, a capacitor C5, a resistor R19 and a resistor R24, the fuse F1 is connected between one end of an external power supply and a fourth end of the inductor LF4, the third end of the inductor LF4 is connected to the other end of the external power supply, the second end of the inductor LF4 is respectively connected to one end of the capacitor XC2 and the second end of the inductor LF3, the first end of the inductor LF4 is respectively connected to the other end of the capacitor XC2 and the The fourth end of the rectifier bridge BD1 is connected, the first end of the inductor LF3 is respectively connected to one end of the capacitor XC1 and the second end of the rectifier bridge BD1, the third end of the inductor LF3 is respectively connected to the other end of the capacitor XC1 and the third end of the rectifier bridge BD1, the first end of the rectifier bridge BD1 is respectively connected to one end of the capacitor C5 and the PFC module (30), the fourth end of the rectifier bridge BD1 is respectively connected to the other end of the capacitor C5, one end of the resistor R19, one end of the resistor R24 ​​and the main control module (20), and the other end of the resistor R19 and the other end of the resistor R24 ​​are grounded.

3. According to claim 1, a small power amplifier audio switching power supply with high power density, characterized in that: The PFC module (30) comprises a gallium nitride switch device Q3, an inductor L3, diodes D4-D6, a resistor RT1, resistors R21-R22, a resistor R25, a resistor R29-R30, a resistor R38, a capacitor C6, a capacitor EC5 and a capacitor EC6, one end of the inductor L3 is respectively connected to the input rectifier filter module (10) and the anode of the diode D4, the other end of the inductor L3 is respectively connected to the anode of the diode D5 and the input end of the gallium nitride switch device Q3, the cathode of the diode D4 is respectively connected to the cathode of the diode D5 and the resistor RT 1, the control end of the gallium nitride switch device Q3 is respectively connected to the anode of the diode D6, one end of the resistor R28 and one end of the resistor R30, the cathode of the diode D6 is connected to the other end of the resistor R28 and is connected to the main control module (20) via the resistor R22, the output end of the gallium nitride switch device Q3 is respectively connected to the other end of the resistor R30, one end of the resistor EC5 and one end of the capacitor EC6, the other end of the capacitor EC5 is respectively connected to the other end of the capacitor EC6, the other end of the resistor RT1, one end of the capacitor C6, one end of the resistor R21 and the LLC power conversion module (40), the other end of the resistor R21 is connected to the other end of the capacitor C6 and is connected to the main control module (20) via the resistor R25 and the resistor R29.

4. A small power amplifier audio switching power supply with high power density according to claim 1, characterized in that: The LLC power conversion module (40) comprises a first drive circuit (41), a second drive circuit (42), a gallium nitride switch device Q5, a gallium nitride switch device Q6, an inductor T4, a transformer T3 and a capacitor C19. The first drive circuit (41) is connected between the main control module (20) and the control end of the gallium nitride switch device Q5, the second drive circuit (42) is connected between the main control module (20) and the control end of the gallium nitride switch device Q6, the input end of the gallium nitride switch device Q5 is connected to VBUS, the output end of the gallium nitride switch device Q5 is respectively connected to the input end of the gallium nitride switch device Q6 and one end of the inductor T4, the other end of the inductor T4 is connected to one end of the primary winding of the transformer T3, the other end of the primary winding of the transformer T3 is respectively connected to the main control module (20) and one end of the capacitor C19, the other end of the capacitor C19 is grounded, and the secondary winding of the transformer T3 is connected to the synchronous rectification module (50).

5. A small power amplifier audio switching power supply with high power density according to claim 4, characterized in that: The first drive circuit (41) comprises a resistor R27, a resistor R32, a resistor R33 and a diode D7, one end of the resistor 27 is respectively connected to the main control module (20) and one end of the resistor R32, the other end of the resistor R32 is respectively connected to the other end of the diode R27, one end of the resistor R33 and the control end of the gallium nitride switch device Q5 via the diode D7, and the other end of the resistor R33 is connected to the output end of the gallium nitride switch device Q5.

6. A small power amplifier audio switching power supply with high power density according to claim 4, characterized in that: The second drive circuit (42) comprises a resistor R35, a resistor R37, a resistor R40 and a diode D9, one end of the resistor R35 is respectively connected to the main control module (20) and one end of the resistor R37, the other end of the resistor R37 is respectively connected to the other end of the diode R35, one end of the resistor R40 and the control end of the gallium nitride switch device Q6 via the diode D9, and the other end of the resistor R40 is connected to the output end of the gallium nitride switch device Q6.

7. A small power amplifier audio switching power supply with high power density according to claim 1, characterized in that: The synchronous rectification module (50) comprises a synchronous rectification chip U8, a MOS transistor Q4, a MOS transistor Q7, a resistor R26, a resistor R34, a resistor R36, a resistor R41 and capacitors C8-C11, the drain of the MOS transistor Q4 is respectively connected to the LLC power conversion module (40) and one end of the resistor R36, the gate of the MOS transistor Q4 is connected to the VG2 end of the synchronous rectification chip U8, the drain of the MOS transistor Q7 is respectively connected to the LLC power conversion module (40) and one end of the resistor R41, the gate of the MOS transistor Q7 is connected to the VG1 end of the synchronous rectification chip U8, and the source of the MOS transistor Q4 is connected to the VG2 end of the synchronous rectification chip U8. The source of the MOS tube Q7 is connected to the AGND terminal, the capacitor C9 and the resistor R34 are connected in parallel between the LL terminal and the PGND terminal of the synchronous rectifier chip U8, the other end of the resistor R36 is connected to the VD2 terminal of the synchronous rectifier chip U8 and is respectively connected to the VSS terminal of the synchronous rectifier chip U8 and one end of the capacitor C11 through the capacitor C10, the other end of the capacitor C11 is respectively connected to one end of the resistor R41 and the VD1 terminal of the synchronous rectifier chip U8, one end of the resistor R26 is connected to the power supply, and the other end is respectively connected to the VDD terminal of the synchronous rectifier chip U8 and one end of the capacitor C8, and the other end of the capacitor C8 is connected to the AGND terminal.

8. According to claim 1, a small power amplifier audio switching power supply with high power density is characterized in that: The feedback module (70) comprises an optical coupler U4, an optical coupler U6, transistors Q10-Q11, a voltage regulator U7, voltage regulator diodes ZD1-ZD2, resistors R6-R7, a resistor R11, resistors R14-R15, resistors R17-R18, a resistor R20, a resistor R23, a resistor R31 and a capacitor C7, one end of the resistor R6 is connected to the standby power module (60), the other end of the resistor R6 is respectively connected to the base of the transistor Q10, the collector of the transistor Q11 and one end of the resistor R15, the emitter of the transistor Q10 is respectively connected to one end of the light emitter of the optical coupler U4 and one end of the resistor R11, the other end of the light emitter of the optical coupler U4 is connected to the other end of the resistor R11 and connected to the power supply via the resistor R7, and the other end of the resistor R15 is respectively connected to the base of the transistor Q10, the collector of the transistor Q11 and one end of the resistor R15. The emitter of the transistor Q10 is connected to the emitter of the triode Q11, the base of the triode Q11 is connected to one end of the resistor R18 and one end of the capacitor C7 via the resistor R14, the voltage zener diode ZD1, and the voltage zener diode ZD2 respectively, the other end of the resistor R18 is connected to one end of the capacitor C7 and the resistor R23 is connected to one end of the resistor R31 and the control end of the voltage stabilizer U7 respectively, the other end of the resistor R31 is connected to the input end and the ground end of the voltage stabilizer U7 respectively, the output end of the voltage stabilizer U7 is connected to one end of the light emitter of the optical coupler U6 and one end of the resistor R20 respectively, the other end of the light emitter of the optical coupler U6 is connected to the other end of the resistor R20 and connected to the power supply via the resistor R17, and the light receiver of the optical coupler U4 and the light receiver of the optical coupler U6 are connected to the main control module (20).

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