The single chip TDA 1190 integrates all important functions needed to work as a TV audio circuit.
The IF signal is simply connected to its input and the output is connected to a loudspeaker. The internal functions of the IC are:
- * IF amplifier and limiter
- * Active lowpass
- * FM demodulator
- * AF preamplifier
- * AF final amplifier
- * Volume control
The circuit uses a minimum number of external components. It can operate from 4.5 MHz up to 6 MHz and therefore applicable for all types of TV system.
The power supply can be between 12 and 24 volts. With a supply voltage of 12 volts, the power output is around 1.5 Watts (8 ohm load impedance).
It delivers 4.2 Watts at 24 volts supply voltage and 16 ohms load impedance.
The input line is connected to a ceramic filter Murata SFE 5.5 MA since the input impedance is very high. The amplification of the circuit is determined by R4.
The upper limit of the audio frequency range is dependent on the value of C10.
The signal to noise ratio is around 70 dB while the AM suppresion is around 55 dB. Its input sensitivity is around 30ÁV.
Table 97.0 shows the normal values of R4 according to the supply voltage and speaker load impedance. The frequency range is between 50 Hz and 12 kHz when the Vss is 24 volts
and speaker impedance = 16 and R4= 18. This will become narrower between 50 Hz and 9.1 kHz when the R4 = 10 ohms.
The IC must be heatsinked and the heatsink must be connected to the circuit ground.
|| 24 V
Electronic Circuits volume 1.0 - Circuit Nr. 97
The complete data of the electronic circuit described above can be found in the following book and is available from Amazon.com.
Click on the image to view the book.