Table 2

Comp.

Recom.

Value

Purpose

Larger than

Recommended Value

Smaller than

Recommended Value

R1

22k

Ω

Closed loop gain setting

Increase of gain

Decrease of gain

R2

680

Ω

Closed loop gain setting

Decrease of gain (*)

Increase of gain

R3

22k

Ω

Non inverting input biasing

Increase of input impedance

Decrease of input impedance

R4

1

Ω

Frequency Stability

Danger of oscillation at high

frequencies with inductive

loads

R5

≅ 3R2

Upper Frequency Cut-off

Poor High Frequencies

Attenuation

Danger of Oscillation

C1

1

µF

Input DC Decoupling

Increase of low frequencies

cut-off

C2

22

µF

Inverting DC Decoupling

Increase of low frequencies

cut-off

C3, C4

0.1

µF

Supply Voltage Bypass

Danger of Oscillation

C5, C6

100

µF

Supply Voltage Bypass

Danger of Oscillation

C7

0.22

µF

Frequency Stability

Larger Bandwidth

C8

≈

1

2

πBR1

Upper Frequency Cut-off

Smaller Bandwidth

Larger Bandwidth

D1, D2

1N4001

To protect the device against output voltage spikes

Table 1

Mains

(220V)

Secondary

Voltage

+ 20%

28.8V

43.2V

42V

37.5V

+ 15%

27.6V

41.4V

40.3V

35.8V

+ 10%

26.4V

39.6V

38.5V

34.2V

–

24V

36.2V

35V

31V

– 10%

21.6V

32.4V

31.5V

27.8V

– 15%

20.4V

30.6V

29.8V

26V

– 20%

19.2V

28.8V

28V

24.3V

A regulated supply is not usually used for the power

output stages because of its dimensioning must be

done taking into account the power to supply in the

signal peaks. They are only a small percentage of

the total music signal, with consequently large

overdimensioning of the circuit.

Even if with a regulated supply higher output power

tions), the additional cost and power dissipation do

not usually justify its use. Using non-regulated sup-

plies, there are fewer designe restriction. In fact,

when signal peaks are present, the capacitor filter

acts as a flywheel supplying the required energy.

In average conditions, the continuous power sup-

plied is lower. The music power/continuous power

ratio is greater in this case than for the case of

regulated supplied, with space saving and cost

reduction.

(*) The value of closed loop gain must be higher than 24dB.

APPLICATION SUGGESTION

The recommended values of the components are

those shown on application circuit of Figure 14.

Different values can be used. The Table 2 can help

the designer.

SHORT CIRCUIT PROTECTION

The TDA2030A has an original circuit which limits

the current of the output transistors. This function

can be considered as being peak power limiting

rather than simple current limiting. It reduces the

possibility that the device gets damaged during an

accidental short circuit from AC output to ground.

THERMAL SHUT-DOWN

The presence of a thermal limiting circuit offers the

following advantages:

1.

An overload on the output (even if it is

permanent), or an above limit ambient

temperature can be easily supported since the

2.

The heatsink can have a smaller factor of

safety compared with that of a conventional

circuit. There is no possibility of device damage

due to high junction temperature. If for any

reason, the junction temperature increases up

to 150

reduces the power dissipation and the current

consumption.

TDA2030A

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