30 W AF amplifier for cars
30 W AF amplifier for cars
The power that can be obtained from a standard car radio amplifieroperating from a 12 V car battery is 5–6W, which (formany listeners) is not really enough for satisfactoryhi-fi reproduction. It is, of course, possible to boost the 12 Vsupply with a power inverter, but that is fairly expensive andnot always acceptable. Now, a Philips IC enables audio powerof about 30 W to be obtained from a 12 V car battery.
Until not so long ago, the Class B outputstages of a standard car radiocould not deliver more than 2ïƒ—ï€ 5–6 Wrmsinto 4 ïƒ™ï€ loudspeakers. More was not possiblewith a single supply line of 12 V. Mostmodern car radios use bridge amplifiers toboost the output to 12–16 W. Often, eachof the four loudspeakers has its own dedicatedamplifier.
Many car manufacturersdo not like the use of power inverters toraise the on-board voltage out of fear thatthese can cause (embarrassing or evendangerous) interference with the remainderof the electronic systems in the car (ofwhich there can be many). There is alsothe problem of heat generation in the outputstages, which may necessitate forcedcooling.Class HElectronics manufacturers have been researchingways and means of obtaining adequateoutput power without the use of apower inverter, and Philips have come upwith the TDA1560Q.Output amplifiers can be arranged in anumber of different configurations, ofwhich most audio enthusiasts only knowClass A and Class B.
A different one thatprovides fairly high output power with relativelylow dissipation is Class G. In thisconfiguration, use is made of two supplyvoltages: a fairly low one that is constantlyavailable and a much higher one that becomesavailable only when the the voltageswing of the output stages can not be sustainedby the low supply voltage.