Sigma-Delta type power amplifier and modulation method thereof
A technology for power amplifiers and amplifiers, applied to amplifiers, amplifiers with semiconductor devices/discharge tubes, incremental modulation, etc., which can solve problems such as expensive, performance degradation of amplifiers, and increased costs
Inactive Publication Date: 2008-03-05
KASH TECH
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Problems solved by technology
One of the disadvantages of this system is that the high-order sigma-delta modulator will be less stable due to the introduction of quantizer hysteresis, so the magnetic values in the look-up table 28 must be preset for each range of the input signal Vin. optimal value of hysteresis
In addition, because the hysteresis of the quantizer 24 is discrete, it is easy to cause other problems
Furthermore, the quantizer 24 must use a variable hysteresis device, the circuit is more complicated and more expensive, and the increased digital converter 26 and look-up table 28 make the chip larger and increase the cost
[0009] There is another problem with the power amplifier 10 of FIG. 1. Because the power stage 18 is not linear, the negative feedback from the output of the quantizer 16 does not accurately represent the true output signal Vout, so the error introduced will make the amplifier 10 performance degradation of
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[0057] Fig. 3 shows a sigma-delta type power amplifier 30 according to the present invention, a sigma-delta modulator 32 is used to convert the input signal Vin into a signal S, which is amplified or reduced into a signal gS by a gain controller 36, where g represents the gain , is determined according to the magnitude of the input signal Vin, and the output stage 34 then generates an output signal Vout from the signal gS for driving the speaker. In a typical system, the output stage 34 includes the quantizer 16 and the power stage 18, but in some digital systems, the output stage 34 includes only the quantizer 16 without the power stage 18, and the output of the quantizer 16 is the output signal Vout. Preferably, the negative feedback is provided from the output signal Vout to the sigma-delta modulator 32 through the inverter 33, so that the real output can be reflected, even if the linearity of the power stage 18 is poor, the performance of the system will not be affected. t...
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This invention relates to a sigma-Delta power amplifier and its modulation method, which plugs a gain controller between a sigma-Delta modulator and an output stage to amply or reduce the signal provided to the output stage by the modulator according to a signal related to the input signal and then provides it to the output level so as to reduce the transformation rate of the modulation.
Description
technical field [0001] The present invention relates to a power amplifier, in particular to a sigma-delta power amplifier. Background technique [0002] The low efficiency of traditional audio signal power amplifiers results in high heat generation, and a large heat sink must be used to help dissipate heat, so the physical device is bulky. In recent years, in order to reduce the size of the amplifier, high-efficiency design schemes have been proposed, and the most common way is to use a class D (class D) amplifier, also known as a switching amplifier. The working principle of this type of amplifier is to use high-frequency modulation to convert an analog or digital input signal into a two-level output signal, and then send the second-level signal to the power stage. , to switch the power switch (power switch) in the power stage. The heat generated by these power switches is extremely low, so the efficiency of the amplifier is greatly improved. [0003] Among the known cla...
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Login to View More IPC IPC(8): H03F3/217H03M3/02H03M7/00
Inventor 秦善平
Owner KASH TECH