一种音频功率放大电路
By optimizing the preamplifier and power amplifier circuit structure of the car amplifier and adopting high-performance operational amplifiers and Class AB power amplifier circuits, the problems of insufficient power output, low sound reproduction and narrow frequency response range of the car amplifier have been solved. High-fidelity audio amplification and compatibility with multiple types of signals have been achieved, meeting users' needs for high-quality in-vehicle audio.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Filing Date
- 2025-06-21
- Publication Date
- 2026-07-17
AI Technical Summary
Existing car amplifiers suffer from insufficient power output, low sound fidelity, narrow frequency response range, susceptibility to distortion, and poor input compatibility, making it difficult to meet users' demands for high-quality in-vehicle audio.
It adopts an audio power amplifier circuit, including a preamplifier and a power amplifier stage. It uses a high-performance NE5532 operational amplifier and a low-noise circuit design, combined with a Class AB power amplifier circuit and a Darlington composite transistor structure, along with multi-stage filtering and amplification circuits, and integrates mute control, overcurrent protection and spike absorption circuits.
It achieves high-fidelity audio amplification, wide frequency response range, compatibility with multiple signal types, and stable high-power output, improving sound quality and circuit reliability, and meeting the needs of complex in-vehicle environments.
Smart Images
Figure CN224521023U_ABST
Abstract
Claims
1. An audio power amplifier circuit, characterized by, The amplifier includes a preamplifier circuit and a power amplifier stage circuit. The preamplifier circuit includes an RCA audio input (1), a high-level audio input (3), and a volume adjustment circuit (5). The left and right channels of the RCA audio input (1) are respectively connected to a preamplifier circuit (2). The left and right channels of the high-level audio input (3) are respectively connected to two preamplifier circuits (4). The two preamplifier circuits (4) located in the same channel are connected to one preamplifier circuit (2). The two preamplifier circuits (4) of the left and right channels are respectively connected to two sets of input terminals of the volume adjustment circuit (5). The power amplifier stage circuit includes two sets of input stage amplifier circuits (6) connected to the output terminals of the two sets of volume adjustment circuits (5). The input stage amplifier circuits (6) are connected to a power amplifier circuit (8) through an excitation stage amplifier circuit (7).
2. An audio power amplifier circuit as claimed in claim 1, characterized in that The first preamplifier circuit (2) includes polarized capacitors C1, C2, and C3, resistors R1, R3, R5, and R6, and operational amplifier U2.
1. One end of resistor R1 is connected to the RCA audio input (1) connector. The other end of resistor R1 is connected to the positive terminal of polarized capacitor C1 and one end of capacitor C2. The negative terminal of polarized capacitor C1 is connected to one end of resistor R3, one end of capacitor C3, and pin 3 of operational amplifier U2.
1. The other end of capacitor C3 is connected to one end of resistor R5, one end of resistor R6, and pin 2 of operational amplifier U2.
1. The other end of resistor R5 is connected to pin 1 of operational amplifier U2.
1. The other ends of capacitor C2, resistor R3, and resistor R6 are grounded respectively.
3. An audio power amplifier circuit as claimed in claim 2, characterized in that The second preamplifier circuit (4) includes capacitor C4, capacitor C5, resistor R2, resistor R4, resistor R7, resistor R8, and operational amplifier U3.
1. One end of resistor R2 is connected to pin 1 of operational amplifier U2.
1. The other end of resistor R2 is connected to one end of resistor R4, one end of capacitor C4, and pin 3 of operational amplifier U3.
1. The other end of capacitor C4 is connected to one end of capacitor C5, one end of resistor R7, one end of resistor R8, and pin 2 of operational amplifier U3.
1. The other end of capacitor C5 is connected to the other end of resistor R8 and pin 1 of operational amplifier U3.
1. The other ends of resistors R4 and R7 are grounded respectively.
4. An audio power amplifier circuit as claimed in claim 3, characterized in that The high-level audio input (3) includes a polarized capacitor C6, a polarized capacitor C7, a resistor R9, a resistor R10, a resistor R11, a resistor R12, and a resistor R13. The two ends of the resistor R11 are connected to the signal. One end of the resistor R11 is connected to one end of the resistor R9. The other end of the resistor R9 is connected to the positive terminal of the polarized capacitor C6. The other end of the polarized capacitor C6 is connected to one end of the resistor R10. The other end of the resistor R10 is connected to pin 3 of the operational amplifier U3.
1. The other end of the resistor R11 is connected to one end of the resistor R12. The other end of the resistor R12 is connected to the positive terminal of the polarized capacitor C7. The negative terminal of the polarized capacitor C7 is connected to one end of the resistor R13. The other end of the resistor R13 is connected to pin 2 of the operational amplifier U3.
1.
5. An audio power amplifier circuit as claimed in claim 4, characterized in that The volume adjustment circuit (5) includes two sets of potentiometers RJ1. One end of the potentiometer RJ1 is connected to pin 1 of the operational amplifier U3.1, and the other end of the potentiometer RJ1 is connected to a grounded resistor R14.
6. An audio power amplifier circuit as claimed in claim 5, characterized in that The input stage amplifier circuit (6) includes polarized capacitors C8, C9, C10, C11, and C12; resistors R15, R16, R17, R18, R19, R20, R21, R22, R23, and R24; NPN transistors Q1, Q2, Q3, and Q4; and a Zener diode D1. One end of resistor R15 is connected to the adjustment terminal of potentiometer RJ1. The other end of resistor R15 is connected to the negative terminal of polarized capacitor C8 and the collector of NPN transistor Q1. The base of NPN transistor Q1 is connected to the mute control signal interface MUTE through resistor R16. The positive terminal of polarized capacitor C8 is connected to one end of resistor R20, one end of capacitor C10, and the base of NPN transistor Q2. The collector of NPN transistor Q2 is connected to one end of resistor R18. The other end of resistor R18 is connected to one end of resistor R17 and resistor R19. One end of the resistor R17 is connected to the cathode of the Zener diode D1, the base of the NPN transistor Q4, and one end of the resistor R23. The other end of the resistor R19 is connected to the collector of the NPN transistor Q3 and one end of the capacitor C9. The emitter of the NPN transistor Q2 is connected to the emitter of the NPN transistor Q3 and the collector of the NPN transistor Q4. The base of the NPN transistor Q3 is connected to the other end of the capacitor C9, the positive terminal of the polarized capacitor C11, and one end of the capacitor C12. The resistor R21 is connected to the negative terminal of the polarized capacitor C11 and the other end of the capacitor C12. The emitter of the NPN transistor Q4 is connected to one end of the resistor R22. The other end of the resistor R22 is connected to the anode of the Zener diode D1. The resistor R24 is connected to one end of the resistor R24 and the other end of the resistor R23. The emitter of the NPN transistor Q1, the other end of the capacitor C10, the other end of the resistor R20, and the other end of the resistor R21 are respectively grounded.
7. An audio power amplifier circuit as claimed in claim 6, characterized in that The excitation stage amplifier circuit (7) includes capacitors C13, C14, C15, and C16; resistors R25, R26, R27, R28, R29, R30, R31, R32, R33, and R34; PNP transistors Q5, Q6, Q7, Q8, Q9, and Q10; diodes D2, D3, and D4. One end of resistor R28 is connected to one end of capacitor C12 and one end of capacitor C15. The other end of resistor R28... The signal interface FB is connected to the terminal. The other end of capacitor C15 is connected to one end of resistor R29, the collector of PNP transistor Q5, the emitter of PNP transistor Q7, one end of capacitor C16, the anode of diode D3, and the base of NPN transistor Q6. The base of PNP transistor Q5 is connected to the collector of NPN transistor Q2 and one end of capacitor C13. The emitter of PNP transistor Q5 is connected to one end of resistor R26 and one end of resistor R27. The other end of capacitor C13 is connected to one end of resistor R25. The other end of resistor R25 is connected to one end of resistor R19 and the other end of resistor R26. One end of capacitor C14 is connected to the collector of NPN transistor Q6. The other end of capacitor C14 is connected to the other end of resistor R27. The other end of resistor R29 is connected to one end of resistor R30. The other end of resistor R30 is connected to one end of resistor R31 and the base of PNP transistor Q7. The other end of resistor R31 is connected to the anode of diode D2. The cathode of diode D2 is connected to the collector of PNP transistor Q7, the base of PNP transistor Q9, the collector of NPN transistor Q10, the other end of capacitor C16, and the cathode of diode D4. The NPN transistor Q1... The base of transistor Q0 is connected to the collector of PNP transistor Q8. The emitter of PNP transistor Q8 is connected to one end of resistor R23. The base of PNP transistor Q8 is connected to the other end of resistor R23. The emitter of NPN transistor Q10 is connected to one end of resistor R34. The other end of resistor R34 is connected to one end of resistor R24. The collector of PNP transistor Q9 is connected to the collector. The emitter of PNP transistor Q9 is connected to one end of resistor R33. The other end of resistor R33 is connected to one end of resistor R32. The other end of resistor R32 is connected to the emitter of NPN transistor Q6.
8. An audio power amplifier circuit as claimed in claim 7, characterized in that The power amplifier circuit (8) includes capacitors C17 and C18, resistors R35, R36, R37, R38, R39, R40, R41, R42, R43, R44, R45, R46, R47, R48, and R49, NPN transistors Q11 and Q12, PNP transistors Q13 and Q14, PNP transistors Q15, diode D5, and inductor L1. One end of resistor R35 is connected to the emitter of NPN transistor Q6, and the other end of resistor R35 is connected to the base of NPN transistor Q11. The collector of NPN transistor Q11 is connected to the cathode of diode D3 and the collector of NPN transistor Q12. The emitter of NPN transistor Q11 is connected to one end of resistor R36 and one end of resistor R37. The other end of resistor R37 is connected to one end of resistor R32, one end of resistor R38, one end of resistor R40, one end of resistor R41, one end of resistor R45, one end of resistor R48, one end of capacitor C17, one end of inductor L1, and the emitter of PNP transistor Q15. The other end of resistor R38 is connected to one end of resistor R42 and the emitter of PNP transistor Q13. The base of PNP transistor Q13 is connected to resistor R39. One end of the resistor R39 is connected to the emitter of the PNP transistor Q9. The collector of the PNP transistor Q13 is connected to the anode of the diode D4, the collector of the PNP transistor Q14, and one end of the resistor R44. The other end of the resistor R36 is connected to the base of the NPN transistor Q12. The emitter of the NPN transistor Q12 is connected to the other end of the resistor R40. The other end of the resistor R42 is connected to the base of the PNP transistor Q14. The emitter of the PNP transistor Q14 is connected to the other end of the resistor R41 and one end of the resistor R43. The other end of the resistor R43 is connected to the other end of the resistor R44 and the other end of the resistor R45. One end of the capacitor C17 is connected to the other end of the capacitor C17, the cathode of the diode D5, and the base of the PNP transistor Q15. One end of the capacitor C17 is connected to the signal interface FB. The anode of the diode D5 is connected to one end of the resistor R46, and the other end of the resistor R46 is grounded. The collector of the PNP transistor Q15 is connected to one end of the resistor R47, and the other end of the resistor R47 is connected to the overcurrent detection interface OCP. The other end of the inductor L1 is connected to the other end of the resistor R48 and one end of the resistor R49. The other end of the resistor R49 is connected to one end of the capacitor C18, and the other end of the capacitor C18 is grounded. The other end of the inductor L1 is connected to the power amplifier output interface OUT.
9. An audio power amplifier circuit as claimed in claim 3, characterized in that The operational amplifier U2.1 in the first preamplifier circuit (2) and the operational amplifier U3.1 in the second preamplifier circuit (4) are both NE5532 operational amplifiers. The first preamplifier circuit (2) and the second preamplifier circuit (4) are respectively connected to a ±15V power supply.
10. The audio power amplifier circuit of claim 1, wherein, The input stage amplifier circuit (6) and the excitation stage amplifier circuit (7) are respectively connected to a ±33V power supply, and the power amplifier circuit (8) is connected to a ±30V power supply.