Remote volume control, power supply, and headphone amplifier design for a studio series stereo audio amplifying system
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Date
2012
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Abstract
A switched-mode power supply (switching-mode power supply, SMPS, or simply switcher ) is an electronic power supply that incorporates a switching regulator in order to be highly efficient in the conversion of electrical power. An SMPS is usually employed to efficiently provide a regulated output voltage. Unlike a linear power supply, the pass transistor of a switching mode supply switched very quickly ( typically between 10KHz to 1MHz ) between full-on and full-off states, which minimizes wasted energy. In this design, AC to DC convertor, SMPS circuit, having a power MOSFET for switching operation and a PWM based feedback circuit for driving the switching of the MOSFET, is designed. We have taken a input of 220V AC, and of frequency 50Hz, it is stepped down. After being stepped down, it is rectified and passed through filter capacitor to give an unregulated DC voltage. The process of chopping is done via MOSFET, which works as a switch to control the output voltage here. A high frequency diode bridge is used with the help of fast recovery diodes 1N4148. Capacitor is then used to remove any ripples and regulate the outputs. At the end, voltage regulators are used to give results close to the desired values. Control circuitry or the feedback portion includes generation of square wave which is then converted in triangular, via op-amp integrator circuit. This control circuitry is used to control the gating signal produced by the MOSFET, which in turn controls the output voltage value. If the output voltage value is higher than desired one, the pulse width of gating signal reduces and vice versa, which automatically compensated for the changes in output voltages and stabilizes it.
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Keywords
Remote Volume Control, Power Supply, Headphone Amplifier, Electrical Engineering