A power amplifier circuit compatible with multiple package chips and a circuit board

Abstract

This invention provides a power amplifier circuit and circuit board compatible with multiple packaged chips. It includes a universal connection terminal for at least four groups of power amplifier chips with different packages. Each universal connection terminal corresponds to a pin function of the power amplifier chip, including a power input terminal, an audio signal input terminal, a control signal input terminal, and an audio signal output terminal. A power supply circuit is connected to a power source, and its output terminal is connected to the power input terminal to provide operating power to the power amplifier chips. An audio input circuit receives an audio signal and, after signal conditioning and high-frequency filtering, outputs a first differential signal to the audio signal input terminal. A control circuit receives a control signal, processes it, and outputs it to the control signal input terminal. An audio output circuit is connected to the audio signal output terminal and receives a second differential signal processed by the power amplifier chips, outputting it to an audio device. This invention achieves compatibility with power amplifier chips of different package sizes by designing a universal power amplifier circuit and circuit board.

Description

Technical Field

[0001] This utility model relates to the field of audio power amplifier circuit technology, specifically to a power amplifier circuit and circuit board compatible with multiple packaged chips. Background Technology

[0002] Modern network cameras not only need to achieve video shooting and transmission functions, but also often come equipped with audio acquisition and playback functions, such as two-way intercom, for communication between monitoring personnel and on-site personnel, or to play alarm sounds. These all require power amplifier circuits to amplify the audio signals to drive the speakers to produce sound.

[0003] Currently, network camera equipment on the market typically uses a single, suitable power amplifier chip, depending on factors such as application scenarios, audio requirements, power consumption, and cost budget. Therefore, the peripheral power amplifier circuit is often designed for a specific packaged power amplifier chip. However, this fixed-package design becomes problematic when the chip malfunctions or market demands for network camera size, cost, sound quality, and functionality change. This necessitates replacing the chip with one of a different package size, usually requiring a complete redesign of the power amplifier circuit and a new electrical layout for the circuit board. Designing different circuits for different packaged chips not only significantly increases R&D costs and time but also hinders rapid adjustments, poor production management, and slows down product iteration and diversification, resulting in poor product versatility.

[0004] Therefore, there is an urgent need to design a power amplifier circuit that is compatible with different packaging forms and can flexibly switch between different power amplifier chips, so as to improve the versatility and flexibility of circuit design and reduce R&D costs and product iteration cycles. Utility Model Content

[0005] This utility model provides a power amplifier circuit and circuit board compatible with multi-package chips. It is mainly used to solve the problems that existing power amplifier circuits and circuit boards cannot be compatible with power amplifier chips of different package sizes, which leads to increased R&D costs and time, difficulty in quickly adjusting to market changes, and poor product versatility. The present invention achieves the effect of being compatible with power amplifier chips of different package sizes, improving the versatility and flexibility of circuit design, and reducing R&D costs and product iteration cycles.

[0006] This utility model achieves the above objectives through the following technical solutions: A power amplifier circuit compatible with multiple packaged chips includes a power supply circuit, an audio input circuit, a control circuit, and an audio output circuit. It is provided with at least four sets of universal connection terminals for power amplifier chips with different packages. These universal connection terminals correspond to the pin functions of the power amplifier chips, including a power input terminal, an audio signal input terminal, a control signal input terminal, and an audio signal output terminal. The power supply circuit is connected to a power source, and its output terminal is connected to the power input terminal to provide operating power to the power amplifier chips. The audio input circuit receives an audio signal and, after signal conditioning and high-frequency filtering, outputs a first differential signal to the audio signal input terminal. The control circuit receives a control signal, processes it, and outputs it to the control signal input terminal. The control signal is used to control the operating state of the power amplifier chips. The audio output circuit is connected to the audio signal output terminal and receives a second differential signal processed by the power amplifier chips, then outputs the second differential signal to an audio device.

[0007] A further embodiment is that the universal connection terminal also includes a ground terminal and a bypass terminal, the ground terminal being connected to ground, and the bypass terminal being shorted to the in-phase input terminal of the audio signal input terminal.

[0008] A further option is that the power amplifier chip is an IC8002D chip in an SOP-8 package or an SGM4890 chip in an MSOP-8 package.

[0009] A further solution is that the correspondence between each of the general-purpose connection terminals and the functional pins of the IC8002D chip itself is as follows: the power input terminal corresponds to pin 7 of the chip; the audio signal input terminal corresponds to pins 3 and 4 of the chip; the control signal input terminal corresponds to pin 1 of the chip; the audio signal output terminal corresponds to pins 5 and 8 of the chip; the ground terminal corresponds to pin 6 of the chip; and the bypass terminal corresponds to pin 2 of the chip.

[0010] The correspondence between each of the general-purpose connection terminals and the functional pins of the SGM4890 chip itself is as follows: the power input terminal corresponds to pin 6 of the chip; the audio signal input terminal corresponds to pins 5 and 7 of the chip; the control signal input terminal corresponds to pin 1 of the chip; the audio signal output terminal corresponds to pins 8 and 2 of the chip; the ground terminal corresponds to pin 4 of the chip; and the bypass terminal corresponds to pin 3 of the chip.

[0011] A further embodiment is that the power supply circuit is provided with a first filter circuit, which includes a first capacitor and a second capacitor. The first capacitor and the second capacitor are connected in parallel and then connected to the input terminal of the power supply circuit to filter out high-frequency ripple and noise in the power supply.

[0012] A further option is that the audio input circuit is a differential input circuit, including a first input circuit and a second input circuit.

[0013] The first input circuit receives the audio signal and includes an input coupling circuit, a second filtering circuit, and a voltage divider circuit. The input coupling circuit is used to isolate the DC component in the audio signal and output the AC audio signal to the input terminal of the second filtering circuit. The second filtering circuit is used to filter out high-frequency noise. The voltage divider circuit is used to divide the AC audio signal and connect it to the inverting input terminal of the audio signal input terminal.

[0014] The second input circuit includes a third capacitor, one end of which is connected to the non-inverting input terminal of the audio signal input terminal, and the other end is grounded.

[0015] A power amplifier circuit board compatible with multiple packaged chips includes the aforementioned power amplifier circuit compatible with multiple packaged chips. A plurality of composite pads are provided on the power amplifier circuit board according to various general connection terminals. The composite pads include a first pad and a second pad for soldering a first power amplifier chip and a second power amplifier chip, respectively. The package size of the first power amplifier chip is larger than the package size of the second power amplifier chip. The outline of the first pad includes the outline of the second pad.

[0016] A further option is to provide a safety distance between the first pad and the second pad, wherein the safety distance is ≥0.4mm.

[0017] Therefore, this utility model has the following beneficial effects: 1. This utility model sets up a universal connection terminal to unify the pins of power amplifier chips with different packages into the same functional interface, and designs the power amplifier circuit to be compatible with the peripheral circuits of different models of power amplifier chips. This makes the circuit design compatible with power amplifier chips of different package sizes, thereby making the design of the entire audio equipment product more flexible. This improves the universality and flexibility of the circuit design and reduces R&D costs and product iteration cycles.

[0018] 2. This utility model designs a power amplifier circuit that is compatible with power amplifier chips of different package sizes, so that a suitable power amplifier chip can be flexibly selected according to market demand without having to redesign the entire power amplifier circuit, which greatly improves the versatility of the circuit design.

[0019] 3. In the PCB design stage, this utility model reserves suitable installation positions and electrical connection paths for two different packaged power amplifier chips. In terms of pad placement, the pads of the small packaged power amplifier chip are overlapped in the internal area of ​​the large packaged power amplifier chip. When replacing the chip, it is only necessary to solder the chip of different package at the corresponding position on the circuit board, which facilitates product upgrades and maintenance.

[0020] 4. The power amplifier circuit design of this utility model is simple and the circuit board layout is compact. The circuit module design and component selection can be directly upgraded according to actual needs, and there is a large space for cost optimization. Especially when the prices of different packages fluctuate in different periods and market environments, the chip with a more advantageous price can be flexibly selected according to cost accounting, which greatly improves the market competitiveness of the product.

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a power amplifier circuit compatible with multiple packaged chips provided in this embodiment of the utility model.

[0023] Figure 2 This is a partial PCB layout diagram of a power amplifier circuit board compatible with multi-packaged chips provided in an embodiment of this utility model. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the described embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0025] An embodiment of a power amplifier circuit and circuit board compatible with multiple packaged chips. See Figure 1This utility model relates to a power amplifier circuit compatible with multiple packaged chips, including a power supply circuit 10, an audio input circuit 20, a control circuit 30, and an audio output circuit 40. It is equipped with at least four sets of universal connection terminals for power amplifier chips U37 / U38 with different packages. These universal connection terminals correspond to the pin functions of the power amplifier chips U37 / U38, including a power input terminal V+, audio signal input terminals +IN and -IN, a control signal input terminal SHDN, and audio signal output terminals Vo1 and Vo2. The power supply circuit 10 is connected to a 5V power supply, and its output terminal is connected to the power input terminal V+ to provide operating power for the power amplifier chips U37 / U38. The audio input circuit 20 is connected to the audio signal input terminal V+. The AUD_OUT signal is used to output the first differential signal to the audio signal input terminals +IN and -IN after signal conditioning and high-frequency filtering. The control circuit 30 receives the control signal SPK_EN, processes the signal, and outputs it to the control signal input terminal SHDN. The control signal SPK_EN is used to control the working state of the power amplifier chips U37 / U38. The audio output circuit 40 is connected to the audio signal output terminals Vo1 and Vo2, and is used to receive the second differential signals LINE_OUTP1 and LINE_OUTN1 processed by the power amplifier chips U37 / U38, and output the second differential signals LINE_OUTP1 and LINE_OUTN1 to the audio device.

[0026] Specifically, this embodiment unifies the pins of power amplifier chips with different packages to the same functional interface by setting a universal connection terminal, and designs the power amplifier circuit to be compatible with the peripheral circuits of different models of power amplifier chips. This makes the circuit design compatible with power amplifier chips of different package sizes, thereby making the design of the entire audio equipment product more flexible. On the one hand, it allows for flexible selection of suitable power amplifier chips according to market demand without redesigning the entire power amplifier circuit, greatly improving the versatility of the circuit design. On the other hand, it facilitates product upgrades and maintenance: when upgrading products, a power amplifier chip with better performance but a different package can be selected without redesigning the entire power amplifier circuit; in after-sales maintenance, if a chip is damaged, a replacement chip with the corresponding package can be selected directly for replacement based on inventory, improving maintenance efficiency.

[0027] In this embodiment, the general connection terminal also includes a ground terminal GND and a bypass terminal Bypass. The ground terminal GND is connected to ground, and the bypass terminal Bypass is shorted to the non-inverting input terminal +IN of the audio signal input terminal.

[0028] In this embodiment, the power amplifier chip is either IC8002D chip U37 in SOP-8 package or SGM4890 chip U38 in MSOP-8 package.

[0029] In this embodiment, the correspondence between each of the general connection terminals and the functional pins of the IC8002D chip itself is as follows: the power input terminal V+ corresponds to pin 7 of the chip; the audio signal input terminals +IN and -IN correspond to pins 3 and 4 of the chip; the control signal input terminal SHDN corresponds to pin 1 of the chip; the audio signal output terminals Vo1 and Vo2 correspond to pins 5 and 8 of the chip; the ground terminal GND corresponds to pin 6 of the chip; and the bypass terminal Bypass corresponds to pin 2 of the chip.

[0030] The correspondence between each of the general-purpose connection terminals and the functional pins of the SGM4890 chip is as follows: the power input terminal V+ corresponds to pin 6 of the chip; the audio signal input terminals +IN and -IN correspond to pins 5 and 7 of the chip; the control signal input terminal SHDN corresponds to pin 1 of the chip; the audio signal output terminals Vo1 and Vo2 correspond to pins 8 and 2 of the chip; the ground terminal GND corresponds to pin 4 of the chip; and the bypass terminal Bypass corresponds to pin 3 of the chip.

[0031] In this embodiment, the power supply circuit 10 is provided with a first filter circuit, which includes a first capacitor C647 and a second capacitor CP41. The first capacitor C647 and the second capacitor CP41 are connected in parallel and then connected to the input terminal of the power supply circuit 10 to filter out high-frequency ripple and noise in the power supply.

[0032] Specifically, in this embodiment, the first capacitor C647 is a 1uF, 10V ceramic capacitor with good temperature resistance; the second capacitor CP41 is a 10uF, 10V surface mount capacitor with small size, which facilitates compact circuit layout.

[0033] Specifically, the circuit design of the first filter circuit described above in this embodiment is a preferred method and not the only circuit structure. For example, a π-type filter circuit may be used depending on the filtering requirements.

[0034] Specifically, the power supply circuit 10 in this embodiment also includes a bridging resistor R684. The circuit is temporarily connected by the series resistor R684 at the input terminal for circuit testing. During the test, the resistor is replaced with a corresponding fixed resistor as needed to measure the operating current of the power amplifier chip U37 / U38.

[0035] Specifically, in this embodiment, the bridging resistor R684 is an 0R resistor with a precision of 5%, which has a small parasitic inductance. Together with the first capacitor C647 and the second capacitor CP41, it forms an LC filter network to suppress high-frequency noise on the power supply line.

[0036] In this embodiment, the audio input circuit 20 is a differential input circuit, including a first input circuit 21 and a second input circuit 22.

[0037] The first input circuit 21 receives the audio signal AUD_OUT and includes an input coupling circuit, a second filtering circuit, and a voltage divider circuit. The input coupling circuit is used to isolate the DC component in the audio signal AUD_OUT and output the audio AC signal to the input terminal of the second filtering circuit. The second filtering circuit is used to filter out high-frequency noise. The voltage divider circuit is used to divide the audio AC signal and connect it to the inverting input terminal -IN of the audio signal input terminal.

[0038] Specifically, the input coupling circuit described in this embodiment uses capacitor C648, which is a 1uF, 10V ceramic capacitor, which is small in size and low in cost.

[0039] Specifically, the coupling method described above in this embodiment is only a preferred method for low-cost design. Transformer coupling can also be selected according to the sound quality requirements of the audio circuit, or optocoupler can be selected for anti-interference considerations.

[0040] Specifically, in this embodiment, the second filtering circuit uses capacitor C646. One end of capacitor C648 is connected to the audio signal AUD_OUT, and its other end is connected to one end of capacitor C646. The other end of capacitor C646 is grounded. After the audio signal AUD_OUT passes through capacitor C648 to "block DC and pass AC", the circuit uses capacitor C646 in parallel for high-frequency filtering.

[0041] Specifically, in this embodiment, capacitor C646 is an 82nF, 10V ceramic capacitor.

[0042] Specifically, the voltage divider circuit in this embodiment includes resistors R686 and R688 connected in series. One end of resistor R686 is connected to capacitor C646, and the other end is led out and connected to the inverting input terminal -IN of the audio signal input terminal. One end of resistor R688 is connected in series with resistor R686, and the other end is led out and connected to the first output terminal Vo1 of the audio signal output terminal. The audio signal output terminal outputs the second differential signals LINE_OUTP1 and LINE_OUTN1 through the first output terminal Vo1 and the second output terminal Vo2.

[0043] Specifically, in this embodiment, resistor R686 is a 20K resistor with a precision of 5%, and resistor R688 is a 100K resistor with a precision of 5%.

[0044] The second input circuit 22 includes a third capacitor C645, one end of which is connected to the non-inverting input terminal +IN of the audio signal input terminal, and the other end is grounded.

[0045] Specifically, in this embodiment, by shorting the Bypass terminal to the non-inverting input (+IN) of the audio signal input, a third capacitor C645 is connected as a bypass circuit. This bypass circuit can reduce voltage fluctuations and electromagnetic interference on the internal power supply lines of the power amplifier chips U37 / U38 by shunting high-frequency noise signals to ground, thereby maintaining the stability of the operating voltage of the power amplifier chips U37 / U38. Furthermore, when using an SGM4890 power amplifier chip U38, the startup time of the chip can be set by adjusting the charging time of the third capacitor C645.

[0046] Specifically, in this embodiment, the third capacitor C645 is a 2.2uF, 10V surface mount capacitor.

[0047] Specifically, in this embodiment, the control circuit 30 includes a resistor R685, a pull-up resistor R689, and a capacitor C687. One end of the resistor R685 is connected to the control signal SPK_EN, and the other end is connected to the 3.3V internal power supply through the pull-up resistor. The signal is filtered by grounding through the capacitor C687, and then connected to the control signal input terminal SHDN.

[0048] Specifically, in this embodiment, resistor R685 and pull-up resistor R689 are both 1K resistors with a precision of 5%, and capacitor C687 is a 100nF, 6.3V ceramic capacitor.

[0049] Specifically, in this embodiment, the shutdown logic of the IC8002D chip and the SGM4890 chip are different. The IC8002D chip enters a low-power sleep mode when it is high, while the SGM4890 chip is turned off when it is low. Therefore, the control logic of the main control chip in the audio device needs to be adjusted when switching, but the connection terminals of the circuit do not need to be adjusted.

[0050] See Figure 2 A power amplifier circuit board compatible with multiple packaged chips includes the aforementioned power amplifier circuit compatible with multiple packaged chips. Several composite pads are provided on the power amplifier circuit board according to various general connection terminals. The composite pads include a first pad and a second pad for soldering a first power amplifier chip U37 and a second power amplifier chip U38, respectively. The package size of the first power amplifier chip U37 is larger than the package size of the second power amplifier chip U38. The outline of the first pad includes the outline of the second pad.

[0051] Specifically, this embodiment uses the IC8002D chip, which is compatible with two different packages, and the SGM4890 chip, which has a smaller package, as examples. The specific differences between these two chips in terms of packaging are: firstly, in terms of physical size, the IC8002D chip has a larger package size, while the SGM4890 chip has a smaller package size; secondly, in terms of pin spacing, the IC8002D chip has a wider pin spacing, while the SGM4890 chip has a narrower pin spacing; thirdly, in terms of assembly and maintenance, the IC8002D chip has lower requirements for SMT processes and is easier to manually solder and repair, while the SGM4890 chip has higher requirements for SMT equipment precision, is more difficult to manually solder, and is more difficult to repair; and fourthly, their heat dissipation performance differs. Through the above-described power amplifier circuit compatible with multiple packaged chips, Based on the above four differences, this embodiment designs a compatibility circuit for the key pins of the two chips that have certain functional similarities. This includes: creating two circuit symbols in the schematic library to represent the power amplifier chips U37 / U38 in different packages; using the same network label, i.e., setting a universal connection terminal. A unified connection and layout are implemented according to the similar pin functions of the power amplifier chips U37 / U38. For example, the power input terminal V+ of both chips uses the same network name OP_5V. That is, the power input OP_5V of the SGM4890 chip and the power input OP_5V of the IC8002D chip use the same external circuit for power input. Thus, when replacing chips, most circuit connections do not need to be redesigned; simply remove the larger package chip and replace it with the smaller package chip.

[0052] Furthermore, during the PCB design phase, suitable mounting locations and electrical connection paths are reserved for the two different packaged power amplifier chips U37 / U38. The first step is to create the packages for the two chips; the second step is to place the pads, overlapping the pads of the smaller packaged power amplifier chip U38 with the internal area of ​​the larger packaged power amplifier chip U37; and then the layout and placement of external components, placing key components in locations that are easily connected to both packages, such as capacitors and resistors. This way, when replacing chips, it is only necessary to solder the chips of different packages to the corresponding positions on the circuit board.

[0053] In this embodiment, a safety distance of ≥0.4mm is provided between the first pad and the second pad.

[0054] The above embodiments are merely preferred embodiments of this utility model and should not be construed as limiting the scope of protection of this utility model. Any non-substantial changes and substitutions made by those skilled in the art based on this utility model shall fall within the scope of protection claimed by this utility model.

Claims

1. A power amplifier circuit compatible with multiple packaged chips, characterized in that, include: The system includes a power supply circuit, an audio input circuit, a control circuit, and an audio output circuit. It also provides at least four sets of universal connection terminals for power amplifier chips with different packages. These universal connection terminals correspond to the pin functions of the power amplifier chips, including a power input terminal, an audio signal input terminal, a control signal input terminal, and an audio signal output terminal. The power supply circuit is connected to a power source, and its output terminal is connected to the power input terminal to provide operating power to the power amplifier chips. The audio input circuit receives an audio signal and, after signal conditioning and high-frequency filtering, outputs a first differential signal to the audio signal input terminal. The control circuit receives a control signal, processes it, and outputs it to the control signal input terminal. This control signal is used to control the operating state of the power amplifier chips. The audio output circuit is connected to the audio signal output terminal and receives a second differential signal processed by the power amplifier chips, then outputs the second differential signal to an audio device.

2. The power amplifier circuit compatible with multi-packaged chips according to claim 1, characterized in that: The general connection terminal also includes a ground terminal and a bypass terminal. The ground terminal is connected to ground, and the bypass terminal is shorted to the in-phase input terminal of the audio signal input terminal.

3. The power amplifier circuit compatible with multi-packaged chips according to claim 2, characterized in that: The power amplifier chip is either an IC8002D chip in an SOP-8 package or an SGM4890 chip in an MSOP-8 package.

4. The power amplifier circuit compatible with multi-packaged chips according to claim 3, characterized in that: The correspondence between each of the general-purpose connection terminals and the functional pins of the IC8002D chip itself is as follows: the power input terminal corresponds to pin 7 of the chip; the audio signal input terminal corresponds to pins 3 and 4 of the chip; the control signal input terminal corresponds to pin 1 of the chip; the audio signal output terminal corresponds to pins 5 and 8 of the chip; the ground terminal corresponds to pin 6 of the chip; and the bypass terminal corresponds to pin 2 of the chip. The correspondence between each of the general-purpose connection terminals and the functional pins of the SGM4890 chip itself is as follows: the power input terminal corresponds to pin 6 of the chip; the audio signal input terminal corresponds to pins 5 and 7 of the chip; the control signal input terminal corresponds to pin 1 of the chip; the audio signal output terminal corresponds to pins 8 and 2 of the chip; the ground terminal corresponds to pin 4 of the chip; and the bypass terminal corresponds to pin 3 of the chip.

5. The power amplifier circuit compatible with multi-packaged chips according to claim 2, characterized in that: The power supply circuit is provided with a first filter circuit, which includes a first capacitor and a second capacitor. The first capacitor and the second capacitor are connected in parallel and then connected to the input terminal of the power supply circuit to filter out high-frequency ripple and noise in the power supply.

6. The power amplifier circuit compatible with multi-packaged chips according to claim 2, characterized in that: The audio input circuit is a differential input circuit, including a first input circuit and a second input circuit; The first input circuit receives the audio signal and includes an input coupling circuit, a second filtering circuit, and a voltage divider circuit. The input coupling circuit isolates the DC component in the audio signal and outputs an AC audio signal to the input terminal of the second filtering circuit. The second filtering circuit filters out high-frequency noise. The voltage divider circuit divides the AC audio signal and connects it to the inverting input terminal of the audio signal input terminal. The second input circuit includes a third capacitor, one end of which is connected to the non-inverting input terminal of the audio signal input terminal, and the other end is grounded.

7. A power amplifier circuit board compatible with multi-package chips, characterized in that, The power amplifier circuit, which includes a multi-package chip compatible circuit as described in any one of claims 1-6, further includes: According to various general connection terminals, a number of composite pads are provided on the power amplifier circuit board. The composite pads include a first pad and a second pad for soldering a first power amplifier chip and a second power amplifier chip, respectively. The package size of the first power amplifier chip is larger than the package size of the second power amplifier chip, and the outline of the first pad includes the outline of the second pad.

8. The power amplifier circuit board compatible with multi-packaged chips according to claim 7, characterized in that: A safety distance of ≥0.4mm is provided between the first pad and the second pad.

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