TDA2030 chip is widely used in audio equipment before, but it can be successfully applied now to build small class AB amplifier devices. In this case, the chip has a pretty good performance in terms of efficiency and provide high-quality sound performance, it is suitable for audio equipment of the middle class.
Appearance and pinout of the chip shown in Figure 1
Power to the power amplifier of the chip may be either unipolar or bipolar, the range of supply voltages in the range of 12 to 28 volts. Optimum operation and claimed characteristics is provided by a voltage supply 14 volts (bipolar embodiment) or 28 volts (unipolar).
The input signal level for the normal operation of the chip can be up to 0.8 volts, i.e. it is capable It works with any standard source signal (data are taken from the technical description in this chip).
A big plus of this chip lies in the fact that it contains a unit of protection against overheating and short-circuit at the output.
But the power of the chip using a standard inclusion is not very high, it is capable of delivering up to 14 watts of power at 4 ohms load. To significantly increase the output power can be applied "bridge" circuit incorporating two such circuits (Figure 2).
In this case, the amplified signal is output from the first chip is supplied to the inverting input through a second resistor R5 and a capacitor C7. As a result, the output of the second chip also appears sound signal but in antiphase to the first (from the output of the first chips).
On the audio head BA1 we get a total signal on both circuits, ie -Increase load voltage, which gives a significant increase in power output.
When the speaker impedance of 4 ohms can be obtained at the output power up to 32 watts. But when working on such a low-resistance load, both chips will work in the "transcendent" mode, which threatens their possible exit from the building, despite the presence of built-in protection circuits.
Therefore, when such inclusion is recommended to use dynamic head with a coil resistance of 6-8 ohms or more lower voltage. When working with 8 ohm load power can be up to +/- 16 volts, with a smaller resistance load supply voltage is recommended to reduce the number of (up to +/- 12... 14 volts).
When producing a power amplifier in a bridge circuit it recommended to increase the capacitance of capacitors C4 and C9 to 1000 uF. To put these capacitors should be as close as possible to the corresponding contact legs of chips and chip set themselves on a small heat sink (about 15-30 square centimeters per chip).
As the diodes in the circuit can be applied, e.g., 1N4001-type diodes - 1N4007 or equivalent.
All electrolytic capacitors must be designed for operating voltages not lower than the supply voltage (with some margin!).
Power supply for the amplifier of this scheme can be applied not stabilized, providing a load current of about 3 amps.