CN209845253U

CN209845253U - High-efficient full-balanced HiFi tuning ear is put

Info

Publication number: CN209845253U
Application number: CN201921026496.4U
Authority: CN
Inventors: 杨奇盛
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-07-03
Filing date: 2019-07-03
Publication date: 2019-12-24
Anticipated expiration: 2029-07-03

Abstract

The embodiment of the utility model discloses high-efficient balanced HiFi tuning ear is put, the frequency range (> 100KHz) that the operating frequency who uses switching power supply chip is far above the stereo set, can not influence the audio circuit, use class AB amplifier circuit, adjust the operating voltage that the ear was put through simple change regulating resistor VR1 and regulating switch P1, although the bias voltage resistance of triode does not change, but operating voltage's change makes the corresponding change of quiescent operating current of triode, thrust and the listening that are used in on the earphone produce the change, the design and the occupation space of circuit have been simplified by a wide margin.

Description

High-efficient full-balanced HiFi tuning ear is put

Technical Field

The embodiment of the utility model provides a relate to HIFI and sound system technical field, concretely relates to high-efficient full balanced HIFI tuning ear is put.

Background

The ear amplifier is an earphone power amplifier connected between an earphone and a sound source, and because the impedance of some high-end earphones is high, or the impedance is low, or the sensitivity is low, the performance of the middle-end and high-end earphones needs to be exerted by using a professional ear amplifier according to the characteristics of the earphones. Common HIFI power amplifiers can be divided into five categories of class A power amplifiers, pure class A power amplifiers, class B power amplifiers, class A and class B power amplifiers and class D power amplifiers, the difference lies in the working condition when the power amplifier receives the sinusoidal signal, namely whether the power amplifier is in the working condition all the time, class A and class B amplifies (class-AB) and is called AB to amplify, for a working condition of the amplifier, the transistor or electron tube amplifier is in the weak conducting state when the input is static, can give good consideration to low crossover distortion and high operating efficiency, it is the mainstream design in the power amplifier.

The class AB ear amplifier adjusts working points by changing quiescent current of triodes, different working points bring different hearing senses on earphones, the common design changes the quiescent current flowing through a first-stage triode and a second-stage triode by changing bias resistance in circuits, the single-channel class AB ear amplifier needs 4 resistors to control the working current, 16 resistors are needed for adjusting the fully balanced four groups of circuits (a left sound channel hot end, a left sound channel cold end, a right sound channel hot end and a right sound channel cold end), the design needs a plurality of switches to switch the resistors, the circuit design is complex, and the occupied space is large.

In addition, the class ab ear amplifier generally uses the operational amplifier to drive and form negative feedback, but the bearing voltage of the common operational amplifier is generally below the positive and negative 18V, so the output swing for driving the class ab ear amplifier is limited by the working voltage, the hearing is easy to be slow, if the electrostatic earphone needs to be driven, the output swing of more than 1000V, the lower operational voltage is difficult to provide enough driving force, the design can be used as the front stage of the electrostatic ear amplifier, and a pair of field effect transistors is matched to be used as the third stage of amplification. If a discrete, fully balanced design is used instead of an operational amplifier, the number of parts required is excessive and the wiring is complicated.

SUMMERY OF THE UTILITY MODEL

Therefore, the embodiment of the utility model provides a high-efficient balanced HiFi tuning ear is put to it is complicated to solve current class ab ear unwrapping wire design, problem that occupation space is big.

In order to achieve the above object, the embodiment of the present invention provides the following technical solutions: a high-efficiency full-balance HiFi tuning ear amplifier comprises a switching power supply chip boosting circuit, a left sound channel balance differential circuit and a right sound channel balance differential circuit;

the switching power supply chip boosting circuit comprises a switching power supply chip U5, a positive voltage output circuit, a negative voltage output circuit and a boosting regulation circuit;

the VIN end of the power supply input of the switching power supply chip U5 is connected with an input power supply;

the positive voltage output circuit comprises a Schottky diode D23 and a polar capacitor C18, the anode of the Schottky diode D23 is connected with the voltage output SW end of the switching power supply chip U5, the cathode of the Schottky diode D23 is connected with the positive voltage output VCC end, the anode of the polar capacitor C18 is connected with the node between the Schottky diode D23 and the positive voltage output VCC end, and the cathode of the polar capacitor C18 is connected with the ground end;

the negative voltage output circuit comprises a polar capacitor C16, a Schottky diode D21, a Schottky diode D22 and a polar capacitor C14, wherein the anode of the polar capacitor C16 is connected with a voltage output SW end of a switching power supply chip U5, the cathode of the polar capacitor C16 is connected with the cathode of the Schottky diode D21, the anode of the Schottky diode D21 is connected with a negative voltage output VSS end, the cathode of the polar capacitor C14 is connected with a node between the Schottky diode D21 and the negative voltage output VSS end, the anode of the polar capacitor C14 is connected with a grounding end, the anode of the Schottky diode D22 is connected with a node between the cathode of the polar capacitor C16 and the cathode of the Schottky diode D21, and the cathode of the Schottky diode D22 is connected with the grounding end;

the boost regulating circuit comprises a voltage regulating switch P1, a voltage regulating resistor VR1, a resistor R45 and a resistor R46, wherein a first end of the voltage regulating switch P1 is connected with a feedback input FB end of a switch power supply chip U5, a second end of the voltage regulating switch P1 is connected with a first end of a voltage regulating resistor VR1, a second end of the voltage regulating resistor VR1 is connected to a node between a Schottky diode D23 and a positive voltage output VCC end, first ends of the resistor R45 and a resistor R46 are respectively connected to a node between a first end of the voltage regulating switch P1 and the feedback input FB end of the switch power supply chip U5, a second end of the resistor R45 is connected to a node between the Schottky diode D23 and the positive voltage output VCC end, and a second end of the resistor R46 is connected to a ground terminal;

the left sound channel balance differential circuit comprises a left sound channel hot end circuit and a left sound channel cold end circuit, the right sound channel balance differential circuit comprises a right sound channel hot end circuit and a right sound channel cold end circuit, the positive pressure output VCC end comprises a VCC _ L end and a VCC _ R end, the negative pressure output VSS end comprises a VSS _ L end and a VSS _ R end, the left sound channel hot end circuit and the left sound channel cold end circuit are connected with the VCC _ L end and the VSS _ L end, and the right sound channel hot end circuit and the right sound channel cold end circuit are connected with the VCC _ R end and the VSS _ R end.

Further, positive pressure output line still includes positive pressure filter line, positive pressure filter line includes inductance L3 and has pole capacitance C19, inductance L3's first end is connected to schottky diode D23's negative pole, inductance L3's second end is connected to positive pressure output VCC end, there is pole capacitance C19's positive pole to be connected to inductance L3's second end and the positive pressure output VCC end between the node, there is the negative pole of pole capacitance C19 to connect the ground terminal.

Further, the negative voltage output line further comprises a negative voltage filter line, the negative voltage filter line comprises an inductor L1 and a polar capacitor C15, a first end of the inductor L1 is connected to an anode of the schottky diode D21, a second end of the inductor L1 is connected to a negative voltage output VSS terminal, a cathode of the polar capacitor C15 is connected to a node between a second end of the inductor L1 and the negative voltage output VSS terminal, and an anode of the polar capacitor C15 is connected to a ground terminal.

Further, the left channel hot end line comprises a high-voltage operational amplifier U2, a resistor R16, a resistor R18, a resistor R4, a resistor R20, a first bias voltage line, a triode Q3, a second bias voltage line, a triode Q8, a triode Q5, a triode Q7, a resistor R14 and a resistor R19;

an inverting input end of the high-voltage operational amplifier U2 is connected with a signal input IN _ L + end after being connected with a resistor R16 IN series, a non-inverting input end of the high-voltage operational amplifier U2 is connected with a resistor R18 IN series and then is connected with a signal input IN _ L-end, and the resistance value of the resistor R16 is the same as that of the resistor R18;

the first bias voltage line comprises a diode D4, a diode D5 and a resistor R13 which are connected in series, wherein the anode of the diode D4 is connected with a VCC _ L end, the resistor R13 is connected with a VSS _ L end, the emitter of the triode Q3 is connected with the VCC _ L end through a resistor R9, the base of the triode Q3 is connected with a node between the cathode of the diode D5 and the resistor R13, the collector of the triode Q3 is connected with the anode of a light-emitting diode D6, the cathode of the light-emitting diode D6 is connected with a first end of a resistor R17, and the second end of the resistor R17 is connected with the output end of the high-voltage operational amplifier U2;

the second bias voltage line comprises a resistor R21, a diode D9 and a diode D10 which are connected in series, the resistor R21 is connected with a VCC _ L end, the cathode of the diode D10 is connected with a VSS _ L end, the emitter of the triode Q8 is connected with the VSS _ L end through a resistor R22, the base of the triode Q8 is connected with a node between the anode of the diode D9 and the resistor R21, and the collector of the triode Q8 is connected with the output end of the high-voltage operational amplifier U2 after being connected with a resistor R17;

the collector of the triode Q5 is connected to a VCC _ L terminal, the emitter of the triode Q5 is connected to a signal output OUT _ L + terminal, the base of the triode Q5 is connected to a node between the collector of the triode Q3 and the anode of the light emitting diode D6, and the resistor R14 is connected between the emitter of the triode Q5 and the signal output OUT _ L + terminal in series;

the collector of the triode Q7 is connected to a VSS _ L terminal, the emitter of the triode Q7 is connected to a signal output OUT _ L + terminal, the base of the triode Q7 is connected to a node between the collector of the triode Q8 and the cathode of the light emitting diode D6, and the resistor R19 is connected between the emitter of the triode Q7 and the signal output OUT _ L + terminal in series;

a first end of the resistor R4 is connected to a node between the inverting input end of the high-voltage operational amplifier U2 and the resistor R16, a second end of the resistor R4 is connected to a signal output OUT _ L + end, a first end of the resistor R20 is connected to a node between the non-inverting input end of the high-voltage operational amplifier U2 and the resistor R18, a second end of the resistor R20 is connected to a ground end, and the resistance values of the resistor R4 and the resistor R20 are the same;

the triode Q3 and the triode Q7 adopt PNP type triodes, and the triode Q8 and the triode Q5 adopt NPN type triodes.

Further, the left channel cold-end line comprises a high-voltage operational amplifier U1, a resistor R6, a resistor R8, a resistor R1, a resistor R11, a third bias voltage line, a triode Q1, a fourth bias voltage line, a triode Q6, a triode Q2, a triode Q4, a resistor R5 and a resistor R10;

an inverting input end of the high-voltage operational amplifier U1 is connected with a signal input IN _ L-end after being connected with a resistor R6 IN series, a non-inverting input end of the high-voltage operational amplifier U1 is connected with a resistor R8 IN series and then is connected with a signal input IN _ L + end, and the resistance value of the resistor R6 is the same as that of the resistor R8;

the third bias voltage line comprises a diode D1, a diode D2 and a resistor R3 which are connected in series, wherein the anode of the diode D1 is connected with a VCC _ L end, the outer end of the resistor R3 is connected with a VSS _ L end, the emitter of the triode Q1 is connected with the VCC _ L end through a resistor R2, the base of the triode Q1 is connected with a node between the cathode of the diode D2 and the resistor R3, the collector of the triode Q1 is connected with the anode of a light emitting diode D3, the cathode of the light emitting diode D3 is connected with the first end of a resistor R7, and the second end of the resistor R7 is connected with the output end of the high-voltage operational amplifier U1;

the fourth bias voltage line comprises a resistor R12, a diode D7 and a diode D8 which are connected in series, the resistor R12 is connected with a VCC _ L end, the cathode of the diode D8 is connected with a VSS _ L end, the emitter of the triode Q6 is connected with the VSS _ L end through a resistor R15, the base of the triode Q6 is connected with a node between the anode of the diode D7 and the resistor R12, and the collector of the triode Q6 is connected with the output end of the high-voltage operational amplifier U1 through a resistor R7;

the collector of the triode Q2 is connected with a VCC _ L terminal, the emitter of the triode Q2 is connected with a signal output OUT _ L-terminal, the base of the triode Q2 is connected with a node between the collector of the triode Q1 and the anode of the light-emitting diode D3, and the resistor R5 is connected between the emitter of the triode Q2 and the signal output OUT _ L-terminal in series;

the collector of the triode Q4 is connected with a VSS _ L end, the emitter of the triode Q4 is connected with a signal output OUT _ L + end, the base of the triode Q4 is connected with a node between the collector of the triode Q6 and the negative electrode of the light emitting diode D3, and the resistor R10 is connected between the emitter of the triode Q4 and the signal output OUT _ L-end in series;

the first end of the resistor R1 is connected to a node between the inverting input end of the high-voltage operational amplifier U1 and the resistor R6, the second end of the resistor R1 is connected to the signal output OUT _ L-end, the first end of the resistor R11 is connected to a node between the non-inverting input end of the high-voltage operational amplifier U1 and the resistor R8, the second end of the resistor R11 is connected to the ground end, and the resistance values of the resistor R1 and the resistor R11 are the same;

the triode Q1 and the triode Q4 adopt PNP type triodes, and the triode Q6 and the triode Q2 adopt NPN type triodes.

Further, the right channel hot end line comprises a high-voltage operational amplifier U4, a resistor R38, a resistor R40, a resistor R26, a resistor R42, a fifth bias voltage line, a triode Q11, a sixth bias voltage line, a triode Q16, a triode Q13, a triode Q15, a resistor R36 and a resistor R41;

an inverting input end of the high-voltage operational amplifier U4 is connected with a signal input IN _ R + end after being connected with a resistor R38 IN series, a non-inverting input end of the high-voltage operational amplifier U4 is connected with a resistor R40 IN series and then is connected with a signal input IN _ R-end, and the resistance value of the resistor R38 is the same as that of the resistor R40;

the fifth bias voltage line comprises a diode D14, a diode D15 and a resistor R35 which are connected in series, wherein the anode of the diode D14 is connected with a VCC _ R end, the resistor R35 is connected with a VSS _ R end, the emitter of the triode Q11 is connected with the VCC _ R end through a resistor R31, the base of the triode Q11 is connected with a node between the cathode of the diode D15 and the resistor R35, the collector of the triode Q11 is connected with the anode of a light emitting diode D16, the cathode of the light emitting diode D16 is connected with a first end of a resistor R39, and the second end of the resistor R39 is connected with the output end of the high-voltage operational amplifier U4;

the sixth bias voltage line comprises a resistor R43, a diode D19 and a diode D20 which are connected in series, the resistor R43 is connected with a VCC _ R end, the cathode of the diode D20 is connected with a VSS _ R end, the emitter of the triode Q16 is connected with the VSS _ R end through a resistor R44, the base of the triode Q16 is connected with a node between the anode of the diode D19 and the resistor R43, and the collector of the triode Q16 is connected with the output end of the high-voltage operational amplifier U4 through a resistor R39;

the collector of the triode Q13 is connected to a VCC _ R terminal, the emitter of the triode Q13 is connected to a signal output OUT _ R + terminal, the base of the triode Q13 is connected to a node between the collector of the triode Q11 and the anode of the light emitting diode D16, and the resistor R36 is connected between the emitter of the triode Q13 and the signal output OUT _ R + terminal in series;

the collector of the triode Q15 is connected to the VSS _ R terminal, the emitter of the triode Q15 is connected to the signal output OUT _ R + terminal, the base of the triode Q15 is connected to the node between the collector of the triode Q16 and the cathode of the light emitting diode D16, and the resistor R41 is connected between the emitter of the triode Q15 and the signal output OUT _ R + terminal in series;

the first end of the resistor R26 is connected to a node between the inverting input end of the high-voltage operational amplifier U4 and the resistor R38, the second end of the resistor R26 is connected to the signal output OUT _ R +, the first end of the resistor R42 is connected to a node between the non-inverting input end of the high-voltage operational amplifier U4 and the resistor R40, the second end of the resistor R42 is connected to the ground end, and the resistance values of the resistor R26 and the resistor R42 are the same;

the triode Q11 and the triode Q15 adopt PNP type triodes, and the triode Q16 and the triode Q13 adopt NPN type triodes.

Further, the right channel cold-end line comprises a high-voltage operational amplifier U3, a resistor R28, a resistor R30, a resistor R23, a resistor R33, a seventh bias voltage line, a triode Q9, an eighth bias voltage line, a triode Q14, a triode Q10, a triode Q12, a resistor R27 and a resistor R32;

an inverting input end of the high-voltage operational amplifier U3 is connected with a signal input IN _ R-end after being connected with a resistor R28 IN series, a non-inverting input end of the high-voltage operational amplifier U3 is connected with a resistor R30 IN series and then is connected with a signal input IN _ R + end, and the resistance value of the resistor R28 is the same as that of the resistor R30;

the seventh bias voltage line comprises a diode D11, a diode D12 and a resistor R25 which are connected in series, wherein the anode of the diode D11 is connected with a VCC _ R terminal, the resistor R25 is connected with a VSS _ R terminal, the emitter of the triode Q9 is connected with the VCC _ R terminal through a resistor R24, the base of the triode Q9 is connected with a node between the cathode of the diode D12 and the resistor R25, the collector of the triode Q9 is connected with the anode of a light emitting diode D13, the cathode of the light emitting diode D13 is connected with the first terminal of a resistor R29, and the second terminal of the resistor R29 is connected with the output terminal of the high-voltage operational amplifier U3;

the eighth bias voltage line comprises a resistor R34, a diode D17 and a diode D18 which are connected in series, the resistor R34 is connected with a VCC _ R end, the cathode of the diode D18 is connected with a VSS _ R end, the emitter of the triode Q14 is connected with the VSS _ R end through a resistor R37, the base of the triode Q14 is connected with a node between the anode of the diode D17 and the resistor R34, and the collector of the triode Q14 is connected with the output end of the high-voltage operational amplifier U3 through a resistor R29;

the collector of the triode Q10 is connected to a VCC _ R terminal, the emitter of the triode Q10 is connected to a signal output OUT _ R-terminal, the base of the triode Q10 is connected to a node between the collector of the triode Q9 and the anode of the light emitting diode D13, and the resistor R27 is connected between the emitter of the triode Q10 and the signal output OUT _ R-terminal in series;

the collector of the triode Q12 is connected to the VSS _ R terminal, the emitter of the triode Q12 is connected to the signal output OUT _ R + terminal, the base of the triode Q12 is connected to the node between the collector of the triode Q14 and the cathode of the light emitting diode D13, and the resistor R32 is connected between the emitter of the triode Q12 and the signal output OUT _ R-terminal in series;

the first end of the resistor R23 is connected to a node between the inverting input end of the high-voltage operational amplifier U3 and the resistor R28, the second end of the resistor R23 is connected to the signal output OUT _ R-end, the first end of the resistor R33 is connected to a node between the non-inverting input end of the high-voltage operational amplifier U3 and the resistor R30, the second end of the resistor R33 is connected to the ground end, and the resistance values of the resistor R23 and the resistor R33 are the same;

the triode Q9 and the triode Q12 adopt PNP type triodes, and the triode Q14 and the triode Q10 adopt NPN type triodes.

Furthermore, the model of the switching power supply chip U5 is XL6008, and the working frequency is greater than or equal to 380 KHz.

The embodiment of the utility model provides a have following advantage:

the embodiment of the utility model provides a high-efficient full-balanced HiFi tuning ear is put, use the switching power supply who works at the high frequency, operating frequency is far above the frequency range of stereo set (> 100KHz), make switching power supply can not influence the audio circuit, adjust the operating voltage that class AB ear was put through simply changing regulating resistor VR and regulating switch P, though the unchangeable of the resistance of one-level bias resistor R, R and second grade bias resistor R, the change of voltage makes class AB first grade triode Q, Q and second grade triode Q, Q's quiescent work electric current changes, the thrust and the sense of acting on the earphone change, just adjust with a resistance and can realize the change of earphone thrust and sense, the design and the occupied space of the circuit are greatly simplified.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

The structure, ratio, size and the like shown in the present specification are only used for matching with the content disclosed in the specification, so as to be known and read by people familiar with the technology, and are not used for limiting the limit conditions which can be implemented by the present invention, so that the present invention has no technical essential significance, and any structure modification, ratio relationship change or size adjustment should still fall within the scope which can be covered by the technical content disclosed by the present invention without affecting the efficacy and the achievable purpose of the present invention.

Fig. 1 is a voltage boosting circuit diagram of a switching power supply chip for a high-efficiency full-balanced HiFi tuning amplifier provided in embodiment 1 of the present invention;

fig. 2 is a hot end circuit diagram of a left channel of a high-efficiency full-balanced HiFi tuning ear-play device provided in embodiment 1 of the present invention;

fig. 3 is a schematic diagram of a left channel cold junction line of a high-efficiency full-balanced HiFi tuning device according to embodiment 1 of the present invention;

fig. 4 is a hot end circuit diagram of a right channel of a high-efficiency full-balanced HiFi tuning ear-play device provided in embodiment 1 of the present invention;

fig. 5 is a right track cold junction diagram that embodiment 1 of the utility model provides a high-efficient full balanced HiFi tuning ear was put.

In the figure: the circuit comprises a switching power supply chip boosting circuit 1, a left sound channel balance differential circuit 2, a right sound channel balance differential circuit 3, a left sound channel hot end circuit 21, a left sound channel cold end circuit 22, a right sound channel hot end circuit 31 and a right sound channel cold end circuit 32.

Detailed Description

The present invention is described in terms of specific embodiments, and other advantages and benefits of the present invention will become apparent to those skilled in the art from the following disclosure. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

Example 1

The high-efficiency full-balance HiFi tuning ear amplifier provided by the embodiment comprises a switching power supply chip booster circuit 1, a left channel balance differential circuit 2 and a right channel balance differential circuit 3.

As shown in fig. 1, the switching power supply chip boost circuit 1 is used for providing positive and negative dual power supplies, and the switching power supply chip boost circuit 1 includes a switching power supply chip U5, a positive voltage output circuit, a negative voltage output circuit, and a boost regulation circuit.

The power input VIN end of the switching power supply chip U5 is connected to an input power supply, which in this embodiment adopts +12V power voltage, and the switching power supply chip U5 further includes a feedback input FB end, an enable end EN end, and a ground end GND end. Furthermore, the model of the switching power supply chip U5 is XL6008, mainly considering the fixed frequency of a high-frequency switch, wherein the working frequency is greater than or equal to 380KHz, and the working frequency is far away from the hearing range, and LC filtering is used.

The positive voltage output circuit comprises a Schottky diode D23 and a polar capacitor C18, the anode of the Schottky diode D23 is connected with the voltage output SW end of the switching power supply chip U5, the cathode of the Schottky diode D23 is connected with the positive voltage output VCC end, the anode of the polar capacitor C18 is connected with the node between the Schottky diode D23 and the positive voltage output VCC end, and the cathode of the polar capacitor C18 is connected with the ground end. Further, the positive voltage output line further comprises a positive voltage filter line, the positive voltage filter line comprises an inductor L3 and a polar capacitor C19, a first end of the inductor L3 is connected to a cathode of the Schottky diode D23, a second end of the inductor L3 is connected to a positive voltage output VCC end, a positive electrode of the polar capacitor C19 is connected to a node between a second end of the inductor L3 and the positive voltage output VCC end, and a negative electrode of the polar capacitor C19 is connected to a ground terminal.

Positive voltage is output through a Schottky diode D23 and an active capacitor C18, and low-ripple positive voltage VCC _ L and VCC _ R are output to power amplifier circuits of left and right sound channels after filtering through an inductor L3 and an active capacitor C19.

The negative voltage output circuit comprises a polar capacitor C16, a Schottky diode D21, a Schottky diode D22 and a polar capacitor C14, wherein the anode of the polar capacitor C16 is connected with a voltage output SW end of a switching power supply chip U5, the cathode of the polar capacitor C16 is connected with the cathode of the Schottky diode D21, the anode of the Schottky diode D21 is connected with a negative voltage output VSS end, the cathode of the polar capacitor C14 is connected with a node between the Schottky diode D21 and the negative voltage output VSS end, the anode of the polar capacitor C14 is connected with a grounding end, the anode of the Schottky diode D22 is connected with a node between the polar capacitor C16 and the Schottky diode D21, and the cathode of the Schottky diode D22 is connected with the grounding end. Further, the negative voltage output line further comprises a negative voltage filter line, the negative voltage filter line comprises an inductor L1 and a polar capacitor C15, a first end of the inductor L1 is connected to an anode of the schottky diode D21, a second end of the inductor L1 is connected to a negative voltage output VSS terminal, a cathode of the polar capacitor C15 is connected to a node between a second end of the inductor L1 and the negative voltage output VSS terminal, and an anode of the polar capacitor C15 is connected to a ground terminal.

Negative voltage is output through an active capacitor C16, a Schottky diode D21, a Schottky diode D22 and an active capacitor C14, and low-ripple negative voltage VSS _ L and VSS _ R are output to power amplifier circuits of left and right sound channels after filtering through an inductor L1 and an active capacitor C15.

The boost regulating circuit comprises a voltage regulating switch P1, a voltage regulating resistor VR1, a resistor R45 and a resistor R46, a first end of the voltage regulating switch P1 is connected with a feedback input FB end of a switch power supply chip U5, a second end of the voltage regulating switch P1 is connected with a first end of the voltage regulating resistor VR1, a second end of the voltage regulating resistor VR1 is connected to a node between a Schottky diode D23 and a positive voltage output VCC end, first ends of the resistor R45 and the resistor R46 are equally connected to a node between a first end of the voltage regulating switch P1 and a feedback input FB end of the switch power supply chip U5, a second end of the resistor R45 is connected to a node between the Schottky diode D23 and the positive voltage output VCC end, and a second end of the resistor R46 is connected with a grounding end.

The voltage regulating switch P1 is a switch for regulating the output voltage, when the voltage regulating switch P1 is open, Ra is R45, the output voltage of the switching power supply U5 is determined by the resistances of the resistor R45 and the resistor R46, the output voltage formula is Vo (Ra/R46+1) × 1.25, and the FB pin reference voltage of the switching power supply U5 is assumed to be 1.25V. When the voltage-regulating switch P1 is closed, the resistor R45 is connected in parallel with the voltage-regulating resistor VR1, and Ra is R45 × VR1/(R45+ VR1), so as to change the output voltage of the resistance-regulating switch power supply chip U5 of the VR 1.

The left channel balance differential circuit 2 and the right channel balance differential circuit 3 have the same principle and are respectively used for amplifying left and right channel signals, the left channel balance differential circuit 2 comprises a left channel hot end line 21 and a left channel cold end line 22, the right channel balance differential circuit 3 comprises a right channel hot end line 31 and a right channel cold end line 32, a positive voltage output VCC end comprises a VCC _ L end and a VCC _ R end, a negative voltage output VSS end comprises a VSS _ L end and a VSS _ R end, the left channel hot end line 21 and the left channel cold end line 22 are connected with the VCC _ L end and the VSS _ L end, the right channel hot end line 31 and the right channel cold end line 32 are connected with the VCC _ R end and the VSS _ R end, the line composition and the principle of the cold end and the hot end of the left channel or the right channel are the same, and only the output phase difference of the cold end and the hot end is.

Principle of balanced signal: the signal transmitted by the hot end and the cold end is the same signal, only at the signal transmitting end, a sound signal is divided into two paths, one path enters the hot end in a positive phase, the other path enters the cold end after being subjected to a phase reversal, at the signal receiving end, the signal at the cold end is subjected to a phase reversal, and is combined with the signal at the hot end to obtain a final signal, and the interference signal in the signal can be removed through a transmission mode of balancing the signal.

The combination of the cold side and the hot side of the left and right sound channels will be described in detail with reference to the accompanying drawings.

As shown in fig. 2, the left channel hot side line 21 includes a high voltage operational amplifier U2, a resistor R16, a resistor R18, a resistor R4, a resistor R20, a first bias line, a triode Q3, a second bias line, a triode Q8, a triode Q5, a triode Q7, a resistor R14, and a resistor R19.

The inverting input end ("-") of the high-voltage operational amplifier U2 is connected IN series with the resistor R16 and then connected to the signal input IN _ L + end, the non-inverting input end ("+" end) of the high-voltage operational amplifier U2 is connected IN series with the resistor R18 and then connected to the signal input IN _ L-end, and the resistor R16 and the resistor R18 have the same resistance value. In this embodiment, the U2 selects a high voltage operational amplifier with the model of OPA445, and can supply power at plus or minus 45V, so that the maximum swing of the whole power amplifier output is close to 90V. The high-voltage operational amplifier and the power amplifier triode are powered by the same group, the whole circuit is simple, the number of parts is small, and the space is saved.

The first bias voltage line comprises a diode D4, a diode D5 and a resistor R13 which are connected in series, wherein the anode of the diode D4 is connected with a VCC _ L end, the resistor R13 is connected with a VSS _ L end, the emitter of a triode Q3 is connected with the VCC _ L end through a resistor R9, the base of the triode Q3 is connected with a node between the cathode of the diode D5 and a resistor R13, the collector of the triode Q3 is connected with the anode of a light-emitting diode D6, the cathode of the light-emitting diode D6 is connected with a first end of a resistor R17, and the second end of the resistor R17 is connected with the output end of the high-voltage operational amplifier U2.

The second bias voltage line comprises a resistor R21, a diode D9 and a diode D10 which are connected in series, wherein the resistor R21 is connected with a VCC _ L end, the cathode of the diode D10 is connected with a VSS _ L end, the emitter of the triode Q8 is connected with the VSS _ L end through a resistor R22, the base of the triode Q8 is connected with a node between the anode of the diode D9 and the resistor R21, and the collector of the triode Q8 is connected with the output end of the high-voltage operational amplifier U2 after being connected with a resistor R17.

The collector of the triode Q5 is connected to a VCC _ L terminal, the emitter of the triode Q5 is connected to a signal output OUT _ L + terminal, the base of the triode Q5 is connected to a node between the collector of the triode Q3 and the anode of the light emitting diode D6, and the resistor R14 is connected in series between the emitter of the triode Q5 and the signal output OUT _ L + terminal.

The collector of the triode Q7 is connected to the VSS _ L terminal, the emitter of the triode Q7 is connected to the signal output OUT _ L + terminal, the base of the triode Q7 is connected to the node between the collector of the triode Q8 and the cathode of the light emitting diode D6, and the resistor R19 is connected in series between the emitter of the triode Q7 and the signal output OUT _ L + terminal.

The first end of the resistor R4 is connected to a node between the inverting input end of the high-voltage operational amplifier U2 and the resistor R16, the second end of the resistor R4 is connected to the signal output OUT _ L + end, the first end of the resistor R20 is connected to a node between the non-inverting input end of the high-voltage operational amplifier U2 and the resistor R18, the second end of the resistor R20 is connected to the ground end, and the resistor R4 and the resistor R20 have the same resistance value.

The triode Q3 and the triode Q7 are PNP type triodes, and the triode Q8 and the triode Q5 are NPN type triodes.

The first end of the capacitor C4 is connected to the output end of the high-voltage operational amplifier U2, and the second end of the capacitor C4 is connected to the inverting input end of the high-voltage operational amplifier U2. A capacitor C3 is connected in parallel with two ends of a connection line between the diode D4 and the diode D5, and a capacitor C6 is connected in parallel with two ends of a connection line between the diode D9 and the diode D10.

The working principle is as follows: a first bias circuit composed of a diode D4, a diode D5 and a resistor R13 provides bias voltage for a positive wave primary amplifier tube Q3, the quiescent current of Q3 can be controlled by adjusting a resistor R13, similarly, a second bias circuit composed of a resistor R21, a diode D9 and a diode D10 provides bias voltage for a negative wave primary amplifier tube Q8, the quiescent current of a triode Q8 can be controlled by adjusting R21, the post-stage power output is pushed by a triode Q5 and a triode Q7 which are responsible for positive and negative waves, the resistor R14 and the resistor R19 can be respectively used for adjusting the quiescent voltages of the triode Q5 and the Q7, the amplification factor of the power amplifier is determined by a negative feedback resistor R4 and an R16, the amplification factor R4/R16, a capacitor C4 is used for low-pass filtering, the amplification factor R18 is R16, the R20 is R4, and the amplifier is symmetrical in positive and negative.

As shown in fig. 3, the left channel cold-side line 22 includes a high-voltage operational amplifier U1, a resistor R6, a resistor R8, a resistor R1, a resistor R11, a third bias line, a triode Q1, a fourth bias line, a triode Q6, a triode Q2, a triode Q4, a resistor R5, and a resistor R10.

The inverting input end of the high-voltage operational amplifier U1 is connected IN series with a resistor R6 and then connected to the signal input IN _ L-end, the non-inverting input end of the high-voltage operational amplifier U1 is connected IN series with a resistor R8 and then connected to the signal input IN _ L + end, and the resistance values of the resistor R6 and the resistor R8 are the same.

The third bias voltage line comprises a diode D1, a diode D2 and a resistor R3 which are connected in series, wherein the anode of the diode D1 is connected with the VCC _ L end, the outer end of the resistor R3 is connected with the VSS _ L end, the emitter of a triode Q1 is connected with the VCC _ L end through a resistor R2, the base of the triode Q1 is connected with a node between the cathode of the diode D2 and the resistor R3, the collector of the triode Q1 is connected with the anode of a light emitting diode D3, the cathode of the light emitting diode D3 is connected with the first end of a resistor R7, and the second end of the resistor R7 is connected with the output end of the high-voltage operational amplifier U1.

The fourth bias voltage line comprises a resistor R12, a diode D7 and a diode D8 which are connected in series, wherein the resistor R12 is connected with a VCC _ L end, the cathode of the diode D8 is connected with a VSS _ L end, the emitter of the triode Q6 is connected with the VSS _ L end through a resistor R15, the base of the triode Q6 is connected with a node between the anode of the diode D7 and the resistor R12, and the collector of the triode Q6 is connected with the output end of the high-voltage operational amplifier U1 through a resistor R7.

The collector of the triode Q2 is connected with a VCC _ L terminal, the emitter of the triode Q2 is connected with a signal output OUT _ L-terminal, the base of the triode Q2 is connected with a node between the collector of the triode Q1 and the anode of the light-emitting diode D3, and the resistor R5 is connected between the emitter of the triode Q2 and the signal output OUT _ L-terminal in series.

The collector of the triode Q4 is connected with the VSS _ L end, the emitter of the triode Q4 is connected with the signal output OUT _ L + end, the base of the triode Q4 is connected with the node between the collector of the triode Q6 and the cathode of the light-emitting diode D3, and the resistor R10 is connected between the emitter of the triode Q4 and the signal output OUT _ L-end in series.

The first end of the resistor R1 is connected to a node between the inverting input end of the high-voltage operational amplifier U1 and the resistor R6, the second end of the resistor R1 is connected to the signal output OUT _ L-end, the first end of the resistor R11 is connected to a node between the non-inverting input end of the high-voltage operational amplifier U1 and the resistor R8, the second end of the resistor R11 is connected to the ground end, and the resistor R1 and the resistor R11 have the same resistance value.

The triode Q1 and the triode Q4 are PNP type triodes, and the triode Q6 and the triode Q2 are NPN type triodes.

As shown in fig. 4, the right channel hot side line 31 includes a high voltage operational amplifier U4, a resistor R38, a resistor R40, a resistor R26, a resistor R42, a fifth bias line, a triode Q11, a sixth bias line, a triode Q16, a triode Q13, a triode Q15, a resistor R36, and a resistor R41.

The inverting input end of the high-voltage operational amplifier U4 is connected IN series with a resistor R38 and then connected to the signal input IN _ R + end, the non-inverting input end of the high-voltage operational amplifier U4 is connected IN series with a resistor R40 and then connected to the signal input IN _ R-end, and the resistor R38 and the resistor R40 have the same resistance value.

The fifth bias voltage line comprises a diode D14, a diode D15 and a resistor R35 which are connected in series, wherein the anode of the diode D14 is connected with the VCC _ R end, the resistor R35 is connected with the VSS _ R end, the emitter of a triode Q11 is connected with the VCC _ R end through a resistor R31, the base of the triode Q11 is connected with a node between the cathode of the diode D15 and the resistor R35, the collector of the triode Q11 is connected with the anode of the light emitting diode D16, the cathode of the light emitting diode D16 is connected with the first end of a resistor R39, and the second end of the resistor R39 is connected with the output end of the high-voltage operational amplifier U4;

the sixth bias voltage line comprises a resistor R43, a diode D19 and a diode D20 which are connected in series, wherein the resistor R43 is connected with a VCC _ R terminal, the cathode of the diode D20 is connected with a VSS _ R terminal, the emitter of the triode Q16 is connected with the VSS _ R terminal through a resistor R44, the base of the triode Q16 is connected with a node between the anode of the diode D19 and the resistor R43, and the collector of the triode Q16 is connected with the output end of the high-voltage operational amplifier U4 through a resistor R39;

a first end of the resistor R26 is connected to a node between the inverting input end of the high-voltage operational amplifier U4 and the resistor R38, a second end of the resistor R26 is connected to a signal output OUT _ R + end, a first end of the resistor R42 is connected to a node between the non-inverting input end of the high-voltage operational amplifier U4 and the resistor R40, a second end of the resistor R42 is connected to a ground end, and the resistor R26 and the resistor R42 have the same resistance value;

the triode Q11 and the triode Q15 are PNP type triodes, and the triode Q16 and the triode Q13 are NPN type triodes.

As shown in fig. 5, the right channel cold-side line 32 includes a high-voltage operational amplifier U3, a resistor R28, a resistor R30, a resistor R23, a resistor R33, a seventh bias line, a triode Q9, an eighth bias line, a triode Q14, a triode Q10, a triode Q12, a resistor R27, and a resistor R32.

The inverting input end of the high-voltage operational amplifier U3 is connected with a resistor R28 IN series and then connected with the signal input IN _ R-end, the non-inverting input end of the high-voltage operational amplifier U3 is connected with a resistor R30 IN series and then connected with the signal input IN _ R + end, and the resistance value of the resistor R28 is the same as that of the resistor R30.

The seventh bias voltage line comprises a diode D11, a diode D12 and a resistor R25 which are connected in series, wherein the anode of the diode D11 is connected with the VCC _ R terminal, the resistor R25 is connected with the VSS _ R terminal, the emitter of the triode Q9 is connected with the VCC _ R terminal through a resistor R24, the base of the triode Q9 is connected with a node between the cathode of the diode D12 and the resistor R25, the collector of the triode Q9 is connected with the anode of the light emitting diode D13, the cathode of the light emitting diode D13 is connected with the first terminal of the resistor R29, and the second terminal of the resistor R29 is connected with the output terminal of the high-voltage operational amplifier U3.

The eighth bias voltage line comprises a resistor R34, a diode D17 and a diode D18 which are connected in series, wherein the resistor R34 is connected with a VCC _ R terminal, the cathode of the diode D18 is connected with a VSS _ R terminal, the emitter of the triode Q14 is connected with the VSS _ R terminal through a resistor R37, the base of the triode Q14 is connected with a node between the anode of the diode D17 and the resistor R34, and the collector of the triode Q14 is connected with the output end of the high-voltage operational amplifier U3 through a resistor R29.

The collector of the triode Q10 is connected to the VCC _ R terminal, the emitter of the triode Q10 is connected to the signal output OUT _ R-terminal, the base of the triode Q10 is connected to the node between the collector of the triode Q9 and the anode of the light emitting diode D13, and the resistor R27 is connected in series between the emitter of the triode Q10 and the signal output OUT _ R-terminal.

The collector of the triode Q12 is connected to the VSS _ R terminal, the emitter of the triode Q12 is connected to the signal output OUT _ R + terminal, the base of the triode Q12 is connected to the node between the collector of the triode Q14 and the cathode of the light emitting diode D13, and the resistor R32 is connected in series between the emitter of the triode Q12 and the signal output OUT _ R-terminal.

The first end of the resistor R23 is connected to a node between the inverting input end of the high-voltage operational amplifier U3 and the resistor R28, the second end of the resistor R23 is connected to the signal output OUT _ R-end, the first end of the resistor R33 is connected to a node between the non-inverting input end of the high-voltage operational amplifier U3 and the resistor R30, the second end of the resistor R33 is connected to the ground end, and the resistor R23 and the resistor R33 have the same resistance value.

The triode Q9 and the triode Q12 are PNP type triodes, and the triode Q14 and the triode Q10 are NPN type triodes.

The high-efficiency full-balance HiFi tuning headphone amplifier provided by this embodiment uses a switching power supply working at high frequency, the working frequency is far higher than the frequency range of sound (> 100KHz), so that the switching power supply does not affect the audio circuit, the working voltage of class ab headphone amplifier is adjusted by simply changing the voltage regulating resistor VR and the voltage regulating switch P, although the resistance values of the first-stage bias resistors R, R and the second-stage bias resistors R, and R are not changed, the change of voltage makes the static working currents of the first-stage triodes Q, and Q of class ab amplifier change, the thrust and the hearing sense acting on the headphone change, and the change of the thrust and the hearing sense of the headphone can be realized by adjusting with only one resistor, the design and the occupied space of the circuit are greatly simplified, in addition, the number of discrete components can be reduced by using high-voltage transmission, the circuit is further simplified, the area of a circuit board is reduced, the output distortion of the class AB ear amplifier is smaller due to high-voltage negative feedback, and the control force for pushing the earphone is better.

Although the invention has been described in detail with respect to the general description and the specific embodiments, it will be apparent to those skilled in the art that modifications and improvements can be made based on the invention. Therefore, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. A high-efficiency full-balance HiFi tuning ear amplifier is characterized in that the ear amplifier comprises a switching power supply chip boosting circuit, a left sound channel balance differential circuit and a right sound channel balance differential circuit;

2. The high-efficiency full-balance HiFi tuning ear amplifier is characterized in that the positive voltage output line further comprises a positive voltage filter line, the positive voltage filter line comprises an inductor L3 and a polar capacitor C19, a first end of the inductor L3 is connected to a cathode of a Schottky diode D23, a second end of the inductor L3 is connected to a positive voltage output VCC end, a positive electrode of the polar capacitor C19 is connected to a node between a second end of the inductor L3 and the positive voltage output VCC end, and a negative electrode of the polar capacitor C19 is connected to a ground terminal.

3. The high-efficiency full-balance HiFi tuning ear amplifier is characterized in that the negative voltage output line further comprises a negative voltage filter line, the negative voltage filter line comprises an inductor L1 and a polar capacitor C15, a first end of the inductor L1 is connected to an anode of a Schottky diode D21, a second end of the inductor L1 is connected to a negative voltage output VSS terminal, a cathode of the polar capacitor C15 is connected to a node between a second end of the inductor L1 and the negative voltage output VSS terminal, and an anode of the polar capacitor C15 is connected to a ground terminal.

4. The high-efficiency full-balance HiFi tuning ear amplifier according to claim 1, wherein the left channel hot side line comprises a high-voltage operational amplifier U2, a resistor R16, a resistor R18, a resistor R4, a resistor R20, a first bias voltage line, a triode Q3, a second bias voltage line, a triode Q8, a triode Q5, a triode Q7, a resistor R14 and a resistor R19;

5. The high-efficiency full-balance HiFi tuning ear amplifier is characterized in that the left channel cold end line comprises a high-voltage operational amplifier U1, a resistor R6, a resistor R8, a resistor R1, a resistor R11, a third bias voltage line, a triode Q1, a fourth bias voltage line, a triode Q6, a triode Q2, a triode Q4, a resistor R5 and a resistor R10;

6. The high-efficiency full-balance HiFi tuning ear amplifier according to claim 1, wherein the right channel hot side line comprises a high-voltage operational amplifier U4, a resistor R38, a resistor R40, a resistor R26, a resistor R42, a fifth bias voltage line, a triode Q11, a sixth bias voltage line, a triode Q16, a triode Q13, a triode Q15, a resistor R36 and a resistor R41;

7. The high-efficiency full-balance HiFi tuning ear amplifier of claim 1, wherein the right channel cold-side line comprises a high-voltage operational amplifier U3, a resistor R28, a resistor R30, a resistor R23, a resistor R33, a seventh bias line, a triode Q9, an eighth bias line, a triode Q14, a triode Q10, a triode Q12, a resistor R27 and a resistor R32;

8. The high-efficiency full-balance HiFi tuning ear amplifier is characterized in that the model of the switching power supply chip U5 is XL6008, and the working frequency is greater than or equal to 380 KHz.