TDA7383 Ver la hoja de datos (PDF) - STMicroelectronics

Número de pieza

componentes Descripción

Fabricante

TDA7383

4 x 30W QUAD BRIDGE CAR RADIO AMPLIFIER

STMicroelectronics 

TDA7383

INPUT STAGE

The TDA7383’s inputs are ground-compatible and

can stand very high input signals (± 8Vpk) without

any performances degradation.

If the standard value for the input capacitors

(0.1µF) is adopted, the low frequency cut-off will

amount to 16 Hz.

tion with microprocessor-driven audioprocessors.

The maximum load that pin 25 can sustain is

1KΩ.

Due to its operating principles, the clipping detec-

tor has to be viewed mainly as a power-depend-

Figure 12: Diagnostics circuit.

STAND-BY AND MUTING

STAND-BY and MUTING facilities are both

CMOS-COMPATIBLE. If unused, a straight con-

nection to Vs of their respective pins would be ad-

missible. Conventional low-power transistors can

) be employed to drive muting and stand-by pins in

t(s absence of true CMOS ports or microprocessors.

c R-C cells have always to be used in order to

u smooth down the transitions for preventing any

d audible transient noises.

ro Since a DC current of about 10 uA normally flows

out of pin 22, the maximum allowable muting-se-

P ries resistance (R2) is 70KΩ, which is sufficiently

te high to permit a muting capacitor reasonably

le small (about 1µF).

o If R2 is higher than recommended, the involved

s risk will be that the voltage at pin 22 may rise to

b above the 1.5 V threshold voltage and the device

O will consequently fail to turn OFF when the mute

- line is brought down.

) About the stand-by, the time constant to be as-

t(s signed in order to obtain a virtually pop-free tran-

sition has to be slower than 2.5V/ms.

25

R

Vpin 25

VREF

D95AU303A

Figure 13: Clipping Detection Waveforms.

duc DIAGNOSTICS FACILITY

ro The TDA7383 is equipped with a diagnostics cir-

P cuitry able to detect the following events:

te CLIPPING in the output stage

le OVERHEATING (THERMAL SHUT-DOWN

o proximity)

sOUTPUT MISCONNECTIONS (OUT-GND &

ObOUT-Vs shorts)

ent feature rather than frequency-dependent. This

means that clipping state will be immediately sig-

naled out whenever a fixed power level is

reached, regardless of the audio frequency.

In other words, this feature offers the means to

Diagnostics information is available across an counteract the extremely sound-damaging effects

open collector output located at pin 25 (fig. 12) of clipping, caused by a sudden increase of odd

through a current sinking whenever at least one order harmonics and appearance of serious inter-

of the above events is recognized.

modulation phenomena.

Among them, the CLIPPING DETECTOR acts in

a way to output a signal as soon as one or more

power transistors start being saturated.

As a result, the clipping-related signal at pin 25

takes the form of pulses, which are perfectly syn-

cronized with each single clipping event in the

music program and reflect the same duration time

(fig. 13). Applications making use of this facility

usually operate a filtering/integration of the pulses

train through passive R-C networks and realize a

volume (or tone bass) stepping down in associa-

Another possible kind of distortion control could

be the setting of a maximum allowable THD limit

(e.g. 0.5 %) over the entire audio frequency

range. Besides offering no practical advantages,

this procedure cannot be much accurate, as the

non-clipping distortion is likely to vary over fre-

quency.

In case of OVERHEATING, pin 25 will signal out

the junction temperature proximity to the thermal

shut-down threshold. This will typically start about

2oC before the thermal shut-down threshold is

8/12

Share Link: