tb2946hq TOSHIBA Semiconductor CORPORATION, tb2946hq Datasheet - Page 6

• Manufacturer Part Number: tb2946hq
• Description: 49 W ? 4-ch Btl Audio Power Ic
• Manufacturer: TOSHIBA Semiconductor CORPORATION

4. Layer Short Detection
The TB2946HQ may be properly connected to a load such as a 4-Ω speaker, but one of the speaker lines may
be shorted to ground through a low-impedance path. The TB2946HQ can detect such a condition.
As is the case with output DC offset detection, pin 25 is also activated when there is a short on one of the
speaker lines as shown above. The detection impedance is 3.3Ω (typ.).
This feature allows detection of a short-circuit through a low-impedance path other than the speaker
impedance. It helps to avoid speaker damage in case of anomalous system conditions and improve system
reliability.
Note 3: The detection impedance varies with temperature, as shown above. Experiment with actual hardware.
Figure 7 Typical Detection Impedance vs Junction Temperature (Intended as a Guide)
12
10
8
6
4
2
0
-50
Dete ction impe dance vs junction te mperature
The negative (−) speaker connection is shorted to ground
through a low-impedance path due to some irregularities.
0
IC
50
Figure 6 Layer Short
V
CC
Tj ( ℃ )
GND
100
6
out
out
150
SP = 4 Ω
200
Te st co nditions
Vcc = 1 3.2 V
In tern al resistor
= 200 Ω
5 V-10 kΩ
Pull-u p
TB2946HQ
2009-01-29