TDF8591TH_1

© NXP B.V. 2008. All rights reserved.

Product data sheet

Rev. 01 — 5 March 2008

7 of 34

NXP Semiconductors

TDF8591TH

2

× 100 W SE (4 Ω) or 1 × 310 W BTL (4 Ω) class-D amplifier

When the loudspeaker terminals are short-circuited and the OCP is triggered the

TDF8591TH is switched off completely and will try to restart every 100 ms (see Figure 6):

condition is still present after this time this cycle will be repeated. The average

dissipation will be low because of the small duty cycle

A short-circuit of the loudspeaker terminals to one of the supply lines will also trigger the

activation of the OCP and the amplifier will shut down. During restart the window

protection will be activated. As a result the amplifier will not start up after 100 ms and pin

DIAG will remain LOW until the short-circuit to the supply lines is removed.

Fig 5.

Pin DIAG with activated current limiting

Fig 6.

Restart of the TDF8591TH

001aad838

Ch1 mean

5.03 V

M 20.0 ms

A Ch1 ~ 1.28 V

τ

001aah365

input voltage

current in the

short-circuit

(between the

speaker terminals)

PWM output

pin DIAG

50 ms

50.0 V

∼

5.00 V

Ω

Ch2

Ch4

500 mV

Ch3

1.80 V

10.0 V

M 25.0 ms

Ch1

Ch3

2

3

1

4

50 ms

50 ms