METHOD AND SYSTEM FOR INCREASING EFFICIENCY IN AUDIO AMPLIFIERS

Abstract

The audio amplification system comprises a power supply (100) connected to a feedback circuit (107), which is connected to the amplifier output filter, so that the power supply voltage (100) dynamically adjusts to the amplifier output voltage. Connected to the power supply (100) and mosfets (102) is a capacitor (108) with the function of stabilizing the power supply voltage (100). The system also comprises a control circuit (106), in which the mosfets (102) are connected, which connect to the output filter through an inductor (103) and a capacitor (104). The amplifier output (101) involves a speaker (105).

Claims

1. An efficiency-enhancing system in audio amplifiers comprising a variable power supply, mosfet transistors connected in series to each other and in parallel with an output filter, a control circuit connected in series to said mosfet transistors, wherein said output filter is composed of an inductor and a capacitor connected in parallel, and a speaker connected in parallel to said output filter, characterized in that: said variable power supply is fed back by the audio signal via a feedback component) and a high-impedance capacitor is connected in parallel to said variable power supply and to said mosfet transistors.

2. A method for enhancing efficiency in audio amplifiers comprising the steps of: establishing a variable power supply signal feedback with the audio signal coming from an amplifier output; dynamicly adjusting of the voltage of said variable power supply to a value above the maximum voltage of the amplifier output audio signal.

Description

LIST OF ACCOMPANYING DRAWINGS

[0017] In order for the present invention to be fully understood and put into practice by any person skilled in this technological sector, it is now described in a clear, precise and sufficient way, based on the accompanying drawings listed below, illustrating preferred ways of carrying out the electronic amplification system:

[0018] FIG. 1—electrical circuit of the sound amplification system of the invention;

[0019] FIG. 2—Simplified electrical circuit of class H sound amplification system;

[0020] FIG. 3—audio signal variation graph in Class G amplifiers;

[0021] FIG. 4—electrical circuit of the class D sound amplification system;

[0022] FIG. 5a—graph of the variation of the voltage signal of the power supply based on the output signal of the amplifier of the invention when in stand-by, in schematic form;

[0023] FIG. 5b—graph of the variation of the voltage signal from the power supply based on the output signal of the amplifier of the invention when in operation, in schematic form.

DETAILED DESCRIPTION OF THE INVENTION

[0024] In order to solve the problems of the current state of the art, which requires several power supplies, as in class H amplifiers, or a variable voltage source of high cost and nominal power higher than the conventional, by not allowing the use of a capacitor with high capacitance in its output, as in class G amplifiers, the present invention is detailed.

[0025] A power supply with variable voltage (100), fed back by the audio signal (107), but with slow rate of variation, allowing the use of a capacitor (108) with high capacitance, as used in conventional low-cost sources and is inserted in the circuit schematized in FIG. 1, whose function is to deliver energy quickly and constantly to the amplifier, greatly improving its audio performance, especially in the low-frequency audio spectrum, solving the problem of the current state of the art that does not allow high capacitance in the output of the source due to the need for a rapid variation of its voltage as occurs with class G amplifiers, at the same time eliminates the need for various power supplies used in class H amplifiers. The power supply voltage (100) remains continuous and always above the maximum voltage of the audio signal of the amplifier output. The amplification system also comprises mosfet transistors (102) connected to a control circuit (106) and the output filter, composed of an inductor (103) and a capacitor (104). The amplifier output (101) involves the filter and a speaker (105).

[0026] When in stand-by, that is, when the amplifier output signal is null or minimal, the voltage [501(a)] of the power supply (100) is minimal, reducing the energy consumption of the amplifier components, as shown in FIG. 5a. When in operation the audio signal increases in intensity, the voltage [501(b)] of the power supply (100) remains above the maximum peak voltage of the audio signal (502), in order to maintain the correct operation of the amplifier and with minimal waste of energy. If the audio signal increases further in intensity, the power supply voltage (100) rises in order to always be higher than the peak voltage of the audio signal. Thus, regardless of the voltage level of the amplifier output (101), which generates the audio sent to the speaker (105), the power supply (100) remains dynamically in constant variation, reducing the dissipated energy in the amplifier output components.

COMPARATIVE TESTS BETWEEN THE AMPLIFIERS OF THE STATE OF THE ART AND THE PRESENT INVENTION

[0027] In order to show the technical effect achieved by the present invention, comparative stand-by heating tests (without signal), heating during 1 hour of use and stand-by consumption (without signal) were carried out on amplifiers from the state of the art and the present invention.

[0028] The stand-by heating test was performed for one hour, without audio, with nominal load at the purely resistive output and 14.4 V at the input. The amplifier from the current state of the art showed heating of 15.9° C., while the amplifier of the present invention showed heating of 0.9° C. Table 1 shows the start and end temperatures of the amplifiers, as well as the differences in the start and end temperatures.

TABLE-US-00001 TABLE 1 COMPARATIVE STAND-BY HEATING TEST. Temperature Time State of the art Present invention Start (t = 0)   22° C.   27° C. End (t = 1 hour) 37.9° C. 27.9° C. Difference 15.9° C.  0.9° C.

[0029] The heating test for 1 hour of use was done with purely resistive load at twice the impedance of the product (2Q), in maximum nominal voltage at the output (55 V AC) with musical signal. Simulating the normal operation of the amplifier, the product from the state of the art underwent an increase in temperature of 66.7° C., while the product with the improvements proposed in the present invention showed an increase of 28.5° C., proving the improvement in efficiency. Table 2 shows the evolution of the temperature of the amplifiers over time, as well as the differences in the start and end temperatures.

TABLE-US-00002 TABLE 2 COMPARATIVE HEATING TEST OF THE AMPLIFIERS IN OPERATION. Temperature, ° C. Time, min State of the art Present invention t = 0 (start) 24.1 25.1 t = 10 77.9 49.1 t = 20 87.6 51.0 t = 30 88.4 51.4 t = 40 88.6 52.0 t = 50 89.1 53.1 t = 60 90.8 53.6 Difference 66.7 28.5

[0030] The stand-by consumption test was performed on the connected amplifiers and without audio, with voltage at the input of 14.4 V. The amplifier from the current state of the art presented consumption of 0.945 A without signal at the output, while the amplifier of the present invention presented consumption of 0.451 A, which represents a reduction of around 50% of the current consumed without signal. Table 3 shows the currents consumed for the two amplifiers in stand-by mode.

TABLE-US-00003 TABLE 3 Comparative test of current consumption of amplifiers Current consumed, A State State of the art Present invention Switched off 0.001 0.001 Switched on (silent) 0.945 0.451

[0031] This specification refers to an electrical audio amplification system, equipped with feedback, whose voltage generated by the power supply is dependent on the magnitude of the amplifier output signal. This composition results in a new technical effect in relation to the state of the art, thus proving its novelty, inventive step, descriptive sufficiency [full disclosure] and industrial application, meeting all the requirements for grant of a patent of invention.