Amplifiers

General Description The TDA7293 is a monolithic integrated circuit in Multiwatt15 package, intended for use as audio class AB amplifier in Hi-Fi field applications, such as home stereo, self powered loudspeakers and Topclass TV. Thanks to the wide voltage range and to the high output current capability it is able to supply the highest power into both 4-Ω and 8-Ω loads.The built-in muting function with turn-on delay simplifies the remote operation avoiding on-off switching noises. Parallel mode is possible by connecting several devices and using pin11. High output power can be delivered to very low impedance loads, so   optimizing the thermal dissipation of the system. Features: Multipower BCD technology Very high operating voltage range (±50 V) DMOS power stage High output power (100 W into 8 Ω  THD =10%, with VS = ±40 V) Muting and stand-by functions No switch on/off noise Very low distortion Very low noise Short-circuit protected (with no input signal applied)

Circuit description: Here is the circuit diagram of a simple subwoofer filter that can be operated from a 12V DC supply. Such a circuit is very useful in automobile subwoofer applications. The circuit is nothing but a low pass filter whose pass frequency can be adjusted between 60 to 160 Hz. The circuit is designed around the TL072 dual BIFET opamp IC. Out of the two opamps inside the chip, IC1A is wired as a buffer. The left and right audio inputs after mixing is fed to the input of the IC1A using the DPDT switch S1. Switch S1 is the phase control switch which can be used to make the subwoofer in phase with other speakers. When S1 is in position 2, 180 degree phase shift will be induced.POT R7 can be used for controlling the level. IC1B forms the low pass filter whose pass frequency can be controlled by adjusting the dual gang POT R13. Circuit Features: The circuit can be powered from 12V DC. IC1 must be mounted on a holder. S1 is a DPDT switch. R13 should be a dual gang l