A capacitor multiplexing circuit for class D and class AB audio power amplifiers

Abstract

The utility model discloses a kind of capacitor multiplexing circuit of class D and class AB audio power amplifier, including class D amplifier loop integrator, class AB amplifier output circuit and multiple groups of switches, the class D amplifier loop integrator includes operational amplifier U1, positive terminal integral element and negative terminal integral element, the class AB amplifier output circuit includes class AB amplifier positive terminal output stage circuit and class AB amplifier negative terminal output stage circuit, the multiple groups of switches include first switch group, second switch group, third switch group and fourth switch group.The utility model discloses a kind of capacitor multiplexing circuit of class D and class AB audio power amplifier, solve the problem of large capacitor occupied area, high cost in the chip of existing integrated class AB and class D power amplifier, realize the efficient multiplexing of capacitor under two kinds of modes, while guaranteeing the working performance of class D and class AB mode is not affected.

Description

Technical Field

[0001] This utility model belongs to the field of audio power amplifier technology, specifically relating to a capacitor multiplexing circuit for Class D and Class AB audio power amplifiers. Background Technology

[0002] Existing audio power amplifier chips often integrate Class AB and Class D audio power amplifiers onto the same integrated circuit, using control logic to freely switch between the two modes. Both modes share a relatively large output power transistor, and only one mode operates at a time. However, the circuitry of both Class AB and Class D amplifiers typically requires large capacitors (such as the integrator capacitor in a Class D amplifier and the compensation capacitor in a Class AB amplifier). These capacitors occupy a significant amount of chip area, increasing chip cost and hindering the miniaturization and cost reduction requirements of the product. Utility Model Content

[0003] The main purpose of this invention is to provide a capacitor multiplexing circuit for Class D and Class AB audio power amplifiers, which solves the problems of large capacitor area and high cost in existing integrated Class AB and Class D power amplifier chips, realizes efficient capacitor multiplexing in both modes, and ensures that the working performance of Class D and Class AB modes is not affected.

[0004] To achieve the above objectives, this utility model provides a capacitor multiplexing circuit for Class D and Class AB audio power amplifiers, including a Class D amplifier loop integrator, an Class AB amplifier output circuit, and multiple sets of switches, wherein: The Class D amplifier loop integrator includes operational amplifier U1, a positive-terminal integrator, and a negative-terminal integrator, wherein: The negative input terminal of the operational amplifier U1 is connected to the negative audio input terminal IN_N, and the positive input terminal of the operational amplifier U1 is connected to the positive audio input terminal IN_P. The negative output terminal of the operational amplifier U1 is used as the negative audio output terminal INT_OUTN, and the positive output terminal of the operational amplifier U1 is used as the positive audio output terminal INT_OUTP. The Class AB amplifier output circuit includes a positive output stage circuit and a negative output stage circuit. The positive output stage circuit includes a positive output power transistor group, a positive output high-side zero-adjustment resistor and compensation capacitor group, and a positive output low-side zero-adjustment resistor and compensation capacitor group. The negative output stage circuit includes a negative output power transistor group, a negative output high-side zero-adjustment resistor and compensation capacitor group, and a negative output low-side zero-adjustment resistor and compensation capacitor group. The multiple sets of switches include a first switch group, a second switch group, a third switch group, and a fourth switch group. The negative input terminal and the positive output terminal of the operational amplifier U1 are connected to the positive output stage circuit of the Class AB amplifier through the first switch group and the second switch group. The positive input terminal and the negative output terminal of the operational amplifier U1 are connected to the negative output stage circuit of the Class AB amplifier through the third switch group and the fourth switch group.

[0005] As a further preferred embodiment of the above technical solution, the positive terminal integrating element includes capacitors C5P-C10P and resistor R3P, and the first switch group includes switches S10P-S17P, wherein: The negative input terminal and positive output terminal of the operational amplifier U1 are connected in sequence by a switch S12P, a capacitor C7P, a switch S16P, a switch S15P, a capacitor C10P, and a switch S17P, and the common terminal of switches S16P and S15P is grounded through a resistor R3P. A series switch S11P and a capacitor C6P are connected in parallel between the end of switch S12P closest to the negative input terminal of operational amplifier U1 and the end of capacitor C7P furthest from switch S12P, and a series switch S10P and a capacitor C5P are connected in parallel. A series switch S14P and a capacitor C9P are connected in parallel between the end of switch S15P closest to the negative input terminal of operational amplifier U1 and the end of capacitor C10P furthest from switch S15P. A series switch S13P and a capacitor C8P are also connected in parallel.

[0006] As a further preferred embodiment of the above technical solution, the negative-end integrating element includes capacitors C5N-C10N and resistor R3N, and the third switch group includes switches S10N-S17N, wherein: The positive input terminal and the negative output terminal of the operational amplifier U1 are connected in sequence by a switch S12N, a capacitor C7N, a switch S16N, a switch S15N, a capacitor C10N, and a switch S17N, and the common terminal of switches S16N and S15N is grounded through a resistor R3N. A series switch S11N and a capacitor C6N are connected in parallel between the end of switch S12N closest to the positive input terminal of operational amplifier U1 and the end of capacitor C7N furthest from switch S12N, and a series switch S10N and a capacitor C5N are connected in parallel. A series switch S14N and a capacitor C9N are connected in parallel between the end of switch S15N closest to the positive input terminal of operational amplifier U1 and the end of capacitor C10N furthest from switch S15N. A series switch S13N and a capacitor C8N are also connected in parallel.

[0007] As a further preferred embodiment of the above technical solution, for the positive output stage circuit of the Class AB amplifier, the positive output power transistor group includes field-effect transistors Q1P and Q2P, the positive output high-side zero-adjustment resistor and compensation capacitor group includes resistor R1P, capacitor C1P, and capacitor C2P, the positive output low-side zero-adjustment resistor and compensation capacitor group includes resistor R2P, capacitor C3P, and capacitor C4P, and the second switch group includes switches S1P to S9P, wherein: The common terminal of switch S10P and capacitor C5P is connected to one end of switch S4P; the common terminal of switch S13P and capacitor C8P is connected to one end of switch S5P; the common terminal of switch S12P and capacitor C7P is connected to one end of switch S6P; the common terminal of switch S15P and capacitor C10P is connected to one end of switch S7P; the ends of capacitors C5P, C6P, and C7P furthest from their respective connected switches are all connected to one end of switch S8P; the ends of capacitors C8P, C9P, and C10P furthest from their respective connected switches are all connected to one end of switch S9P. One end of switch S1P is connected to the input terminal PG_P and the gate of the field-effect transistor Q1P. The other end of switch S1P is connected to the other end of switch S4P, the other end of switch S5P, one end of capacitor C1P, and one end of capacitor C2P through resistor R1P. One end of switch S2P is connected to the input terminal NG_P and the gate of the field-effect transistor Q2P. The other end of switch S2P is connected to the other end of switch S6P, the other end of switch S7P, one end of capacitor C3P, and one end of capacitor C4P through resistor R2P. One end of switch S3P is connected to the other ends of capacitors C1P, C2P, C3P, C4P, switch S8P, and S9P, respectively. The other end of switch S3P is connected to the drain of field-effect transistor Q1P, the drain of field-effect transistor Q2P, and the output terminal OUT_P, respectively.

[0008] As a further preferred embodiment of the above technical solution, for the negative output stage circuit of the Class AB amplifier, the negative output power transistor group includes field-effect transistors Q1N and Q2N, the negative output high-side zero-adjustment resistor and compensation capacitor group includes resistor R1N, capacitor C1N, and capacitor C2N, the negative output low-side zero-adjustment resistor and compensation capacitor group includes resistor R2N, capacitor C3N, and capacitor C4N, and the fourth switch group includes S1N-switch S9N, wherein: The common terminal of switch S10N and capacitor C5N is connected to one end of switch S4N; the common terminal of switch S13N and capacitor C8N is connected to one end of switch S5N; the common terminal of switch S12N and capacitor C7N is connected to one end of switch S6N; the common terminal of switch S15N and capacitor C10N is connected to one end of switch S7N; the ends of capacitors C5N, C6N, and C7N furthest from their respective connected switches are all connected to one end of switch S8N; the ends of capacitors C8N, C9N, and C10N furthest from their respective connected switches are all connected to one end of switch S9N. One end of switch S1N is connected to the input terminal PG_N and the gate of the field-effect transistor Q1N. The other end of switch S1N is connected to the other end of switch S4N, the other end of switch S5N, one end of capacitor C1N, and one end of capacitor C2N through resistor R1N. One end of switch S2N is connected to the input terminal NG_N and the gate of the field-effect transistor Q2N. The other end of switch S2N is connected to the other end of switch S6N, the other end of switch S7N, one end of capacitor C3N, and one end of capacitor C4N through resistor R2N. One end of switch S3N is connected to the other ends of capacitors C1N, C2N, C3N, C4N, switch S8N, and S9N, respectively. The other end of switch S3N is connected to the drain of field-effect transistor Q1N, the drain of field-effect transistor Q2N, and the output terminal OUT_N, respectively.

[0009] The beneficial effects of this utility model are as follows: 1. Cost and area optimization: By reusing capacitor banks, the number and total size of independently set capacitors for Class D and Class AB amplifiers are reduced, significantly reducing chip area and chip manufacturing costs, which meets the market demand for miniaturization and low cost of audio power amplifier chips.

[0010] 2. Performance Guarantee: Through the isolation effect of switches (S3P, S3N, S1P~S2P, S1N~S2N), the output power switching signal and power supply signal with voltage glitches in Class D mode are prevented from being affected by mis-conduction interference from the MOSFETs (S4P~S9P, S4N~S9N) or body diodes in the switch group, thus avoiding interference to the integrator and capacitor signals. At the same time, the access path of the multiplexed capacitor group is independent in the two modes, and can be adapted to different performance requirements through parameter adjustment, ensuring that the working performance of Class D and Class AB modes (such as the integration parameters and corresponding loop gain, loop bandwidth, and loop phase margin in Class D, and the phase margin and output stability in Class AB) are not affected.

[0011] 3. Flexibility and compatibility: The circuit supports flexible adjustment of integrator type (first-order, second-order, multi-stage cascade), amplifier type (fully differential, single-ended), capacitor type (polarized, non-polarized), and switching structure, and can be adapted to audio power amplifier chip designs of different specifications, with strong compatibility. Attached Figure Description

[0012] Figure 1 This is the circuit diagram of this utility model.

[0013] Figure 2 This is the circuit diagram of this utility model (and) Figure 1 The circuit structure logic is the same, the difference is that the reused capacitor uses a non-polar double-layer polysilicon capacitor or a metal capacitor, which is suitable for circuit scenarios where the polarity of the capacitor is not required. Detailed Implementation

[0014] The following description is intended to disclose the present invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the present invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the present invention.

[0015] This utility model discloses a capacitor multiplexing circuit for Class D and Class AB audio power amplifiers. The specific embodiments of the utility model are further described below with reference to preferred embodiments.

[0016] In the embodiments of this utility model, those skilled in the art will note that the capacitors and resistors involved in this utility model can be considered as prior art.

[0017] Preferred embodiment.

[0018] like Figure 1 As shown, this utility model discloses a capacitor multiplexing circuit for Class D and Class AB audio power amplifiers, including a Class D amplifier loop integrator, an Class AB amplifier output circuit, and multiple sets of switches, wherein: The Class D amplifier loop integrator includes operational amplifier U1, a positive-terminal integrator, and a negative-terminal integrator, wherein: The negative input terminal of the operational amplifier U1 is connected to the negative audio input terminal IN_N, and the positive input terminal of the operational amplifier U1 is connected to the positive audio input terminal IN_P. The negative output terminal of the operational amplifier U1 is used as the negative audio output terminal INT_OUTN, and the positive output terminal of the operational amplifier U1 is used as the positive audio output terminal INT_OUTP. The Class AB amplifier output circuit includes a positive output stage circuit and a negative output stage circuit. The positive output stage circuit includes a positive output power transistor group, a positive output high-side zero-adjustment resistor and compensation capacitor group, and a positive output low-side zero-adjustment resistor and compensation capacitor group. The negative output stage circuit includes a negative output power transistor group, a negative output high-side zero-adjustment resistor and compensation capacitor group, and a negative output low-side zero-adjustment resistor and compensation capacitor group. The multiple sets of switches include a first switch group, a second switch group, a third switch group, and a fourth switch group. The negative input terminal and the positive output terminal of the operational amplifier U1 are connected to the positive output stage circuit of the Class AB amplifier through the first switch group and the second switch group. The positive input terminal and the negative output terminal of the operational amplifier U1 are connected to the negative output stage circuit of the Class AB amplifier through the third switch group and the fourth switch group.

[0019] Specifically, the positive terminal integrating element includes capacitors C5P-C10P and resistor R3P, and the first switch group includes switches S10P-S17P, wherein: The negative input terminal and positive output terminal of the operational amplifier U1 are connected in sequence by a switch S12P, a capacitor C7P, a switch S16P, a switch S15P, a capacitor C10P, and a switch S17P, and the common terminal of switches S16P and S15P is grounded through a resistor R3P. A series switch S11P and a capacitor C6P are connected in parallel between the end of switch S12P closest to the negative input terminal of operational amplifier U1 and the end of capacitor C7P furthest from switch S12P, and a series switch S10P and a capacitor C5P are connected in parallel. A series switch S14P and a capacitor C9P are connected in parallel between the end of switch S15P closest to the negative input terminal of operational amplifier U1 and the end of capacitor C10P furthest from switch S15P. A series switch S13P and a capacitor C8P are also connected in parallel.

[0020] More specifically, the negative-end integrating element includes capacitors C5N-C10N and resistor R3N, and the third switch group includes switches S10N-S17N, wherein: The positive input terminal and the negative output terminal of the operational amplifier U1 are connected in sequence by a switch S12N, a capacitor C7N, a switch S16N, a switch S15N, a capacitor C10N, and a switch S17N, and the common terminal of switches S16N and S15N is grounded through a resistor R3N. A series switch S11N and a capacitor C6N are connected in parallel between the end of switch S12N closest to the positive input terminal of operational amplifier U1 and the end of capacitor C7N furthest from switch S12N, and a series switch S10N and a capacitor C5N are connected in parallel. A series switch S14N and a capacitor C9N are connected in parallel between the end of switch S15N closest to the positive input terminal of operational amplifier U1 and the end of capacitor C10N furthest from switch S15N. A series switch S13N and a capacitor C8N are also connected in parallel.

[0021] Furthermore, for the positive output stage circuit of the Class AB amplifier, the positive output power transistor group includes MOSFETs Q1P and Q2P, the positive output high-side zero-adjustment resistor and compensation capacitor group includes resistor R1P, capacitor C1P, and capacitor C2P, the positive output low-side zero-adjustment resistor and compensation capacitor group includes resistor R2P, capacitor C3P, and capacitor C4P, and the second switch group includes switches S1P to S9P, wherein: The common terminal of switch S10P and capacitor C5P is connected to one end of switch S4P; the common terminal of switch S13P and capacitor C8P is connected to one end of switch S5P; the common terminal of switch S12P and capacitor C7P is connected to one end of switch S6P; the common terminal of switch S15P and capacitor C10P is connected to one end of switch S7P; the ends of capacitors C5P, C6P, and C7P furthest from their respective connected switches are all connected to one end of switch S8P; the ends of capacitors C8P, C9P, and C10P furthest from their respective connected switches are all connected to one end of switch S9P. One end of switch S1P is connected to the input terminal PG_P and the gate of the field-effect transistor Q1P. The other end of switch S1P is connected to the other end of switch S4P, the other end of switch S5P, one end of capacitor C1P, and one end of capacitor C2P through resistor R1P. One end of switch S2P is connected to the input terminal NG_P and the gate of the field-effect transistor Q2P. The other end of switch S2P is connected to the other end of switch S6P, the other end of switch S7P, one end of capacitor C3P, and one end of capacitor C4P through resistor R2P. One end of switch S3P is connected to the other ends of capacitors C1P, C2P, C3P, C4P, switch S8P, and S9P, respectively. The other end of switch S3P is connected to the drain of field-effect transistor Q1P, the drain of field-effect transistor Q2P, and the output terminal OUT_P, respectively.

[0022] Furthermore, for the negative output stage circuit of the Class AB amplifier, the negative output power transistor group includes MOSFETs Q1N and Q2N, the negative output high-side zero-adjustment resistor and compensation capacitor group includes resistor R1N, capacitor C1N, and capacitor C2N, the negative output low-side zero-adjustment resistor and compensation capacitor group includes resistor R2N, capacitor C3N, and capacitor C4N, and the fourth switch group includes switches S1N to S9N, wherein: The common terminal of switch S10N and capacitor C5N is connected to one end of switch S4N; the common terminal of switch S13N and capacitor C8N is connected to one end of switch S5N; the common terminal of switch S12N and capacitor C7N is connected to one end of switch S6N; the common terminal of switch S15N and capacitor C10N is connected to one end of switch S7N; the ends of capacitors C5N, C6N, and C7N furthest from their respective connected switches are all connected to one end of switch S8N; the ends of capacitors C8N, C9N, and C10N furthest from their respective connected switches are all connected to one end of switch S9N. One end of switch S1N is connected to the input terminal PG_N and the gate of the field-effect transistor Q1N. The other end of switch S1N is connected to the other end of switch S4N, the other end of switch S5N, one end of capacitor C1N, and one end of capacitor C2N through resistor R1N. One end of switch S2N is connected to the input terminal NG_N and the gate of the field-effect transistor Q2N. The other end of switch S2N is connected to the other end of switch S6N, the other end of switch S7N, one end of capacitor C3N, and one end of capacitor C4N through resistor R2N. One end of switch S3N is connected to the other ends of capacitors C1N, C2N, C3N, C4N, switch S8N, and S9N, respectively. The other end of switch S3N is connected to the drain of field-effect transistor Q1N, the drain of field-effect transistor Q2N, and the output terminal OUT_N, respectively.

[0023] For this utility model, such as Figure 1 As shown in the diagram, the capacitors are complementary poly-nwell capacitors with positive and negative polarity. This circuit mainly reuses the integrator capacitor of the Class D audio amplifier and the compensation capacitor of the Class AB audio amplifier, wherein: U1 is a fully differential operational amplifier in the integrator of a fully differential Class D amplifier. IN_N and IN_P are the negative and positive audio input terminals of the integrator, respectively. INT_OUTP and INT_OUTN are the positive and negative audio output terminals of the integrator, respectively. The circuits C5P, C6P, C7P, C8P, C9P, C10P, and R3P constitute the positive integrator of the second-order integrator, while the circuits C5N, C6N, C7N, C8N, C9N, C10N, and R3N constitute the negative integrator of the second-order integrator.

[0024] The dashed box shows the positive and negative output stage circuits of a Class AB amplifier. Q1P and Q2P form the output power transistor group at the positive end, Q1N and Q2N form the output power transistor group at the negative end, R1P, C1P, and C2P are the high-side zero-adjustment resistors and compensation capacitors at the positive end, R2P, C3P, and C4P are the low-side zero-adjustment resistors and compensation capacitors at the positive end, R1N, C1N, and C2N are the high-side zero-adjustment resistors and compensation capacitors at the negative end, and R2N, C3N, and C4N are the low-side zero-adjustment resistors and compensation capacitors at the negative end.

[0025] In Class D operating mode, the on and off states of the switch are as follows: Figure 1 As shown, S10P, S11P, S12P, S13P, S14P, S15P, S16P, S17P and S10N, S11N, S12N, S13N, S14N, S15N, S16N, S17N are in the closed state, while the remaining S1P, S2P, S3P, S4P, S5P, S6P, S7P, S8P, S9P and S1N, S2N, S3N, S4N, S5N, S6N, S7N, S8N, S9N are in the open state. Capacitors C5P, C7P, C8P, C10P and C5N, C7N, C8N, C10N are used as integrator capacitors by the Class D amplifier. Switches S3P and S3N isolate the output OUT_P and OUT_N voltage overshoot and glitches from the signal interference to the Class D integrator and trap capacitor through the switching MOSFETs.

[0026] Conversely, in AB class operating modes, the on and off states of the switch are the same as... Figure 1 Conversely, S10P, S11P, S12P, S13P, S14P, S15P, S16P, S17P and S10N, S11N, S12N, S13N, S14N, S15N, S16N, S17N are in the open state, while the remaining S1P, S2P, S3P, S4P, S5P, S6P, S7P, S8P, S9P and S1N, S2N, S3N, S4N, S5N, S6N, S7N, S8N, S9N are in the closed state. Capacitors C5P, C7P, C8P, C10P and C5N, C7N, C8N, C10N are used as compensation capacitors by the Class AB amplifier.

[0027] Furthermore, the circuit implements a capacitor reuse scheme for Class D and Class AB amplifiers. Depending on the specific circuit parameters, only a portion of the integrator capacitors can be used for reuse, or only a portion of the compensation capacitors can be used for reuse; or... Figure 1 In a Class AB amplifier, the compensation capacitors C1P, C2P, C1N, and C2N can have zero values, or in a Class D amplifier, the integrator capacitors C6P, C9P, C6N, and C9N can have zero values.

[0028] It is worth mentioning that, for example, besides Figure 1 The reuse of Class D second-order integrator capacitors and Class AB compensation capacitors can also be implemented as a reuse of Class D first-order integrator capacitors and Class AB compensation capacitors, a reuse of Class D multi-stage cascaded integrator capacitors and Class AB compensation capacitors, a reuse of compensation capacitors and Class AB compensation capacitors in a Class D operational amplifier, or a reuse of filter / delay capacitors and Class AB compensation capacitors in a Class D operational amplifier. The Class AB compensation circuit and its position in the circuit can also have other structures and locations.

[0029] In addition to the fully differential amplifier form mentioned above, it can also be a single-ended amplifier form.

[0030] In addition to the trap capacitors with positive and negative polarities mentioned above, double-layer polysilicon capacitors or metal capacitors without positive or negative polarities can also be used. For specific circuit implementation methods, please refer to [reference needed]. Figure 2 .

[0031] It is worth mentioning that the technical features such as capacitors and resistors involved in this utility model patent application should be regarded as prior art. The specific structure, working principle, and possible control methods and spatial arrangement of these technical features can be adopted using conventional choices in the field, and should not be regarded as the inventive point of this utility model patent. This utility model patent will not elaborate further.

[0032] For those skilled in the art, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A capacitor multiplexing circuit for Class D and Class AB audio power amplifiers, characterized in that, Includes a Class D amplifier loop integrator, a Class AB amplifier output circuit, and multiple sets of switches, among which: The Class D amplifier loop integrator includes operational amplifier U1, a positive-terminal integrator, and a negative-terminal integrator, wherein: The negative input terminal of the operational amplifier U1 is connected to the negative audio input terminal IN_N, and the positive input terminal of the operational amplifier U1 is connected to the positive audio input terminal IN_P. The negative output terminal of the operational amplifier U1 is used as the negative audio output terminal INT_OUTN, and the positive output terminal of the operational amplifier U1 is used as the positive audio output terminal INT_OUTP. The Class AB amplifier output circuit includes a positive output stage circuit and a negative output stage circuit. The positive output stage circuit includes a positive output power transistor group, a positive output high-side zero-adjustment resistor and compensation capacitor group, and a positive output low-side zero-adjustment resistor and compensation capacitor group. The negative output stage circuit includes a negative output power transistor group, a negative output high-side zero-adjustment resistor and compensation capacitor group, and a negative output low-side zero-adjustment resistor and compensation capacitor group. The multiple sets of switches include a first switch group, a second switch group, a third switch group, and a fourth switch group. The negative input terminal and the positive output terminal of the operational amplifier U1 are connected to the positive output stage circuit of the Class AB amplifier through the first switch group and the second switch group. The positive input terminal and the negative output terminal of the operational amplifier U1 are connected to the negative output stage circuit of the Class AB amplifier through the third switch group and the fourth switch group.

2. The capacitor multiplexing circuit for a Class D and Class AB audio power amplifier according to claim 1, characterized in that, The positive terminal integrating element includes capacitors C5P-C10P and resistor R3P, and the first switch group includes switches S10P-S17P, wherein: The negative input terminal and positive output terminal of the operational amplifier U1 are connected in sequence by a switch S12P, a capacitor C7P, a switch S16P, a switch S15P, a capacitor C10P, and a switch S17P, and the common terminal of switches S16P and S15P is grounded through a resistor R3P. A series switch S11P and a capacitor C6P are connected in parallel between the end of switch S12P closest to the negative input terminal of operational amplifier U1 and the end of capacitor C7P furthest from switch S12P, and a series switch S10P and a capacitor C5P are connected in parallel. A series switch S14P and a capacitor C9P are connected in parallel between the end of switch S15P closest to the negative input terminal of operational amplifier U1 and the end of capacitor C10P furthest from switch S15P. A series switch S13P and a capacitor C8P are also connected in parallel.

3. The capacitor multiplexing circuit for a Class D and Class AB audio power amplifier according to claim 2, characterized in that, The negative-end integrating element includes capacitors C5N-C10N and resistor R3N, and the third switch group includes switches S10N-S17N, wherein: The positive input terminal and the negative output terminal of the operational amplifier U1 are connected in sequence by a switch S12N, a capacitor C7N, a switch S16N, a switch S15N, a capacitor C10N, and a switch S17N, and the common terminal of switches S16N and S15N is grounded through a resistor R3N. A series switch S11N and a capacitor C6N are connected in parallel between the end of switch S12N closest to the positive input terminal of operational amplifier U1 and the end of capacitor C7N furthest from switch S12N, and a series switch S10N and a capacitor C5N are connected in parallel. A series switch S14N and a capacitor C9N are connected in parallel between the end of switch S15N closest to the positive input terminal of operational amplifier U1 and the end of capacitor C10N furthest from switch S15N. A series switch S13N and a capacitor C8N are also connected in parallel.

4. The capacitor multiplexing circuit for a Class D and Class AB audio power amplifier according to claim 3, characterized in that, For the positive output stage circuit of the Class AB amplifier, the positive output power transistor group includes MOSFETs Q1P and Q2P; the positive output high-side zero-adjustment resistor and compensation capacitor group includes resistor R1P, capacitor C1P, and capacitor C2P; the positive output low-side zero-adjustment resistor and compensation capacitor group includes resistor R2P, capacitor C3P, and capacitor C4P; and the second switch group includes switches S1P to S9P, wherein: The common terminal of switch S10P and capacitor C5P is connected to one end of switch S4P; the common terminal of switch S13P and capacitor C8P is connected to one end of switch S5P; the common terminal of switch S12P and capacitor C7P is connected to one end of switch S6P; the common terminal of switch S15P and capacitor C10P is connected to one end of switch S7P; the ends of capacitors C5P, C6P, and C7P furthest from their respective connected switches are all connected to one end of switch S8P; the ends of capacitors C8P, C9P, and C10P furthest from their respective connected switches are all connected to one end of switch S9P. One end of switch S1P is connected to the input terminal PG_P and the gate of the field-effect transistor Q1P. The other end of switch S1P is connected to the other end of switch S4P, the other end of switch S5P, one end of capacitor C1P, and one end of capacitor C2P through resistor R1P. One end of switch S2P is connected to the input terminal NG_P and the gate of the field-effect transistor Q2P. The other end of switch S2P is connected to the other end of switch S6P, the other end of switch S7P, one end of capacitor C3P, and one end of capacitor C4P through resistor R2P. One end of switch S3P is connected to the other ends of capacitors C1P, C2P, C3P, C4P, switch S8P, and S9P, respectively. The other end of switch S3P is connected to the drain of field-effect transistor Q1P, the drain of field-effect transistor Q2P, and the output terminal OUT_P, respectively.

5. The capacitor multiplexing circuit for a Class D and Class AB audio power amplifier according to claim 4, characterized in that, For the negative output stage circuit of the Class AB amplifier, the negative output power transistor group includes MOSFETs Q1N and Q2N; the negative output high-side zero-adjustment resistor and compensation capacitor group includes resistor R1N, capacitor C1N, and capacitor C2N; the negative output low-side zero-adjustment resistor and compensation capacitor group includes resistor R2N, capacitor C3N, and capacitor C4N; and the fourth switch group includes switches S1N to S9N, wherein: The common terminal of switch S10N and capacitor C5N is connected to one end of switch S4N; the common terminal of switch S13N and capacitor C8N is connected to one end of switch S5N; the common terminal of switch S12N and capacitor C7N is connected to one end of switch S6N; the common terminal of switch S15N and capacitor C10N is connected to one end of switch S7N; the ends of capacitors C5N, C6N, and C7N furthest from their respective connected switches are all connected to one end of switch S8N; the ends of capacitors C8N, C9N, and C10N furthest from their respective connected switches are all connected to one end of switch S9N. One end of switch S1N is connected to the input terminal PG_N and the gate of the field-effect transistor Q1N. The other end of switch S1N is connected to the other end of switch S4N, the other end of switch S5N, one end of capacitor C1N, and one end of capacitor C2N through resistor R1N. One end of switch S2N is connected to the input terminal NG_N and the gate of the field-effect transistor Q2N. The other end of switch S2N is connected to the other end of switch S6N, the other end of switch S7N, one end of capacitor C3N, and one end of capacitor C4N through resistor R2N. One end of switch S3N is connected to the other ends of capacitors C1N, C2N, C3N, C4N, switch S8N, and S9N, respectively. The other end of switch S3N is connected to the drain of field-effect transistor Q1N, the drain of field-effect transistor Q2N, and the output terminal OUT_N, respectively.

Images