2x25 W Power Amplifier for Car Sound Systems

Semiconductor manufacturers are always coming up with new techniques and tricks for making effective use of energy. Final amplifiers for car sound systems are no exception.In designing power amplifiers for sound reproduction in vehicles, an output power of somewhat more than 6 W can be generated using a conservative class-B output stage. In spite of this relatively small output power, such stages are found in most car radios for the simple reason that class-B output stages have high efficiency (78.5% with a maximumamplitude sine wave signal); the internal power dissipation is relatively small (20% of the output power). This avoids problems with excessive heat dissipation in the vehicle or the need to use an oversized heat sink, which arises from the fact that the maximum ambient temperature in a vehicle must be assumed to be considerably higher than with a home stereo system, for example, so a car radio cannot be allowed to run as hot.