CN204810237U - Field effect switch tube phase inverter oscillation mode D class amplifier - Google Patents

Abstract

The invention discloses a field effect switch tube inverter oscillation type D class amplifier, which belongs to the field of electronic information technology. The class D amplifier includes an integrating circuit, a Schmitt trigger circuit and a positive feedback network, wherein the integrating circuit integrates the input signal u ₂ to obtain a triangular wave u ₃ whose width is modulated by the input audio signal u ₁ ; u ₃ is shaped to obtain a pulse width modulated square wave u ₄ ; the positive feedback network feeds back the pulse width modulated square wave u ₄ output by the Schmitt trigger circuit to the input terminal of the integrating circuit to be superimposed with the input signal u ₁ . The utility model uses the inverter directly formed by the field effect switch transistor to form a self-oscillating class D amplifier, so that the circuit structure is simpler, compact, practical and easy to integrate.

Description

Oscillating Class-D Amplifier with FET Inverter

technical field

The utility model relates to a field effect switch tube inverter oscillation type D amplifier, which belongs to the technical field of electronic information.

Background technique

The Class D amplifier drives the speaker load by controlling the on or off of the switch unit. The first commercial product was produced in 1960. Compared with general Class A, Class B, and Class AB amplifiers, Class D amplifiers have the advantages of high efficiency and small size. In recent years, they have gradually become popular and are widely used in tablet computers, televisions and portable electronic products. At present, the general class D amplifier usually relies on the integrated circuit as the integrator and Schmitt trigger, and the circuit takes up a large area, and the integration degree is not high.

Contents of the invention

In order to overcome the disadvantages of the prior art, the utility model provides an oscillating class D amplifier based on a field effect switching tube inverter, which has a simple and practical circuit structure and a high degree of integration.

In order to realize the purpose of the invention, the utility model provides an oscillating class D amplifier of a field-effect switching tube inverter, which is characterized in that it includes an integrating circuit, a Schmidt trigger circuit and a positive feedback network, wherein the integrating circuit has an input The signal u ₂ is integrated to obtain the triangular wave u ₃ whose width is modulated by the input audio signal u ₁ : the schmitt trigger circuit shapes the triangular wave u ₃ to obtain a pulse width modulated square wave u ₄ ; the positive feedback network converts the schmitt trigger circuit The output pulse width modulated square wave u ₄ is fed back to the input terminal of the integrating circuit to be superposed with the input signal u ₁ .

Preferably, the integrating circuit includes a first inverter, a capacitor C2 and a resistor R1, wherein the first end of the resistor R1 is connected to the input end of the first inverter and connected to the first end of the capacitor C2; The second end is connected to the output end of the inverter, and the second end of the resistor R1 is connected to the signal input end.

Preferably, the Schmitt trigger circuit includes a second inverter, a third inverter, a fourth inverter, a fifth inverter and a resistor R3, wherein the output terminal of the second inverter is connected to the third The input end of inverter; the output end of the third inverter is connected to the input end of the fourth inverter; the output end of the fourth inverter is connected to the input end of the fifth inverter; the third inverter The output terminal of is connected to the input terminal of the second inverter via the resistor R3.

Preferably, the first inverter, the second inverter, the third inverter, the fourth inverter and the fifth inverter are all composed of two field effect transistors.

Compared with the prior art, the oscillating class D amplifier of the field effect switching tube inverter provided by the utility model has a simple circuit structure and is convenient for integration.

Description of drawings

Fig. 1 is the composition block diagram of the oscillating type D class amplifier of the field effect switching tube inverter provided by the utility model;

Fig. 2 is the integrating circuit diagram that the utility model provides;

Fig. 3 is the Schmidt trigger circuit provided by the utility model;

Fig. 4 is the low-pass filter provided by the utility model;

Fig. 5 is the oscillating type D amplifier of the field effect switching tube inverter of the present invention.

Detailed ways

Below in conjunction with accompanying drawing, describe the utility model in detail.

Fig. 1 is a composition block diagram of an oscillating class D amplifier of a field effect switching tube inverter provided by the utility model. As shown in Figure 1, the oscillating class D amplifier of the field effect switching tube inverter provided by the utility model includes an integrating circuit, a Schmidt trigger circuit, a positive feedback network and a low-pass filter, wherein the integrating circuit is sensitive to the input The signal u ₂ is integrated to obtain the triangular wave u ₃ whose width is modulated by the input audio signal u ₁ ; the schmitt trigger circuit shapes u ₃ to obtain a pulse width modulated square wave u ₄ ; the positive feedback network converts the output of the schmitt trigger circuit The pulse width modulated square wave u ₄ is fed back to the input terminal of the integrating circuit to be superposed with the input signal u ₁ ; the low-pass filter is used to filter the pulse width modulated square wave u ₄ to obtain a linearly amplified audio signal.

Fig. 2 is the integration circuit diagram provided by the utility model. As shown in Figure 2, the integration circuit includes a resistor R1, a first inverter and a capacitor C2, wherein the first inverter includes a P-channel field effect transistor Q1 and an N-channel field effect transistor Q2, and the field The gate of the effect transistor Q1 is connected to the gate of the field effect transistor Q2, and the connected node is the input terminal of the first inverter; the source of the field effect transistor Q1 is connected to the positive pole of the power supply V1, and the drain of the field effect transistor Q1 The pole is connected to the drain of the field effect transistor Q2, and the connected node is the output end of the first inverter; the source of the field effect transistor Q2 is connected to the negative pole of the power supply V1, thus forming an inverter. The first end of the resistor R1 is connected to the input end of the first inverter, and is connected to the first end of the capacitor C2; the second end of the capacitor C2 is connected to the output end of the inverter, thus forming an inverter based on a field effect switch transistor. Integrator of the phaser. The resistor C1 is a coupling capacitor, its first end is connected to the input signal u ₁ , and its second end is connected to the second end of the resistor R1.

Fig. 3 is a Schmitt trigger circuit provided by the utility model. As shown in Figure 3, the Schmitt trigger circuit provided by the utility model includes: a second inverter, a third inverter, a fourth inverter, a fifth inverter and a resistor R3, wherein the four inverters The phase devices have the same composition and structure, and the second inverter includes a P-channel field effect transistor Q3 and an N-channel field effect transistor Q4, wherein the gate of the field effect transistor Q3 is connected to the gate of the field effect transistor Q4, and the The connected node is the input end of the second inverter; the source of the field effect transistor Q3 is connected to the positive pole of the power supply V1, the drain of the field effect transistor Q3 is connected to the drain of the field effect transistor Q4, and the connected node is the first The output terminals of the two inverters; the source of the field effect transistor Q4 is connected to the negative pole of the power supply V1. The third inverter includes a P-channel field effect transistor Q5 and an N-channel field effect transistor Q6, wherein the gate of the field effect transistor Q5 is connected to the gate of the field effect transistor Q6, and the connected node is the third inverter. The input terminal of the inverter; the source of the field effect transistor Q5 is connected to the positive pole of the power supply V1, the drain of the field effect transistor Q5 is connected to the drain of the field effect transistor Q6, and the connected node is the output of the third inverter end; the source of the field effect transistor Q6 is connected to the negative pole of the power supply V1. The fourth inverter includes a P-channel field effect transistor Q7 and an N-channel field effect transistor Q8, wherein the gate of the field effect transistor Q7 is connected to the gate of the field effect transistor Q8, and the connected node is the fourth inverter. The input terminal of the inverter; the source of the field effect transistor Q7 is connected to the positive pole of the power supply V1, the drain of the field effect transistor Q7 is connected to the drain of the field effect transistor Q8, and the connected node is the output of the fourth inverter terminal; the source of the field effect transistor Q8 is connected to the negative pole of the power supply V1. The fifth inverter includes a P-channel field effect transistor Q3 and an N-channel field effect transistor Q4, wherein the gate of the field effect transistor Q3 is connected to the gate of the field effect transistor Q4, and the connected node is the fifth inverter. The input end of the inverter; the source of the field effect transistor Q3 is connected to the positive pole of the power supply V1, the drain of the field effect transistor Q3 is connected to the drain of the field effect transistor Q4, and the connected node is the output of the fifth inverter terminal; the source of the field effect transistor Q4 is connected to the negative pole of the power supply V1. The output terminal of the second inverter is connected to the input terminal of the third inverter; the output terminal of the third inverter is connected to the input terminal of the fourth inverter; the output terminal of the fourth inverter is connected to the fifth inverter input to the inverter. The output end of the third inverter is connected to the input end of the first inverter through the resistor R3, thus forming a Schmitt trigger circuit. The resistor R2 is a current limiting resistor, its first end is connected to the input signal, and its second end is connected to the input end of the second inverter.

Fig. 4 is the low-pass filter provided by the utility model. As shown in Figure 4, the low-pass filter that the utility model provides comprises inductor L1, inductor L2, electric capacity C3, electric capacity C4, electric capacity C5 and resistance R5, wherein, the first end of inductance connects input signal u ₄ ; Connect the first end of the inductor L2, the second end of the inductor L2 is connected to the first end of the capacitor C5, the second end of the capacitor C5 is the signal output end; the first end of the capacitor C3 is connected to the node where the inductor L1 and the inductor L2 are connected , the second terminal is connected to the common terminal; the first terminal of the capacitor C4 is connected to the node where the inductor L2 and the capacitor C5 are connected, and the second terminal is connected to the common terminal; the first terminal of the resistor R5 is connected to the second terminal of the capacitor C5, and the second terminal is connected to the common terminal.

Fig. 5 is the oscillating type D amplifier of the field effect switching tube inverter of the present invention. As shown in Figure 5, the input audio signal u1 is connected to the input terminal of the integrator through the coupling capacitor _C1 ; the output signal of the integrator is connected to the input terminal of the Schmitt trigger through the resistor R2, and the output of the Schmitt trigger The terminal is connected to the input terminal of the integrator through the resistor R4; the output terminal of the Schmitt trigger is connected to the input terminal of the low-pass filter. In this way, an oscillating class D amplifier of a field effect switching tube inverter is formed.

After simulation, the class D amplifier provided by the utility model can linearly amplify the input audio signal without distortion, the degree of distortion can be reduced to the lower limit of the measuring instrument, the efficiency can reach more than 95%, and the performance is good. It can be seen that the oscillating class D amplifier based on the field effect switching transistor inverter provided by the utility model utilizes the inverter directly formed by the field effect switching transistor to form the integrator and Schmidt required for the self-oscillating class D amplifier. The flip-flop makes the circuit structure simpler, compact, practical and easy to integrate. It can be widely used in flat-panel TVs and portable electronic devices, and conforms to the concepts of low carbon, energy saving, environmental protection, and sustainable development.

The utility model has been described in detail above in conjunction with the accompanying drawings, but the description is only used to explain the claims. But the scope of protection of the utility model is not limited to the description. Any changes or replacements that can be easily conceived by those skilled in the art within the technical scope disclosed in the utility model shall be covered by the protection scope of the utility model. Therefore, the protection scope of the present utility model should be based on the protection scope of the claims.

Claims (4)

1. a field effect transistor switch pipe inverter oscillation mode class-D amplifier, is characterized in that, comprises integrating circuit, Schmidt trigger circuit and positive feedback network, and wherein, integrating circuit is to the signal u of input ₂carry out integration and obtain the audio signal u that width is transfused to ₁the triangular wave u of modulation ₃; Schmidt trigger circuit is to triangular wave u ₃carry out shaping and obtain pulse-width modulation square wave u ₄; The pulse-width modulation square wave u that Schmidt trigger circuit exports by positive feedback network ₄feed back to the input of integrating circuit, with the signal u with input ₁superpose.

2. field effect transistor switch pipe inverter oscillation mode class-D amplifier according to claim 1, it is characterized in that, integrating circuit comprises the first inverter, electric capacity C2 and resistance R1, wherein, the first end of resistance R1 is connected to the input of the first inverter, and is connected to the first end of electric capacity C2; Second end of electric capacity C2 is connected to the output of inverter, the second end connection signal input of resistance R1.

3. field effect transistor switch pipe inverter oscillation mode class-D amplifier according to claim 2, it is characterized in that, Schmidt trigger circuit comprises the second inverter, the 3rd inverter, the 4th inverter, the 5th inverter and resistance R3, wherein, the output of the second inverter is connected to the input of the 3rd inverter; The output of the 3rd inverter is connected to the input of the 4th inverter; The output of the 4th inverter is connected to the input of the 5th inverter; The output of the 3rd inverter is connected to the input of the second inverter through resistance R3.

4. field effect transistor switch pipe inverter oscillation mode class-D amplifier according to claim 3, it is characterized in that, the first inverter, the second inverter, the 3rd inverter, the 4th inverter and the 5th inverter form by two field effect transistor.