SLVA824A January 2017 – July 2025 TAS6422-Q1 , TAS6424-Q1 , TAS6424L-Q1 , TPA3111D1-Q1 , TPA3221 , TPA3244 , TPA3245 , TPA3250 , TPA3251 , TPA3255 , TPA3255-Q1
Table 3-2 shows the supply voltage used in data collection, as well as the threshold voltages measured for each of the comparators.
| Parameter | Value (V) |
|---|---|
| Supply Voltage | 12.033 |
| V_Ref + | 6.86 |
| V_Ref - | 5.157 |
| V _Ref Differential | 2.76 |
Using the parameters from Table 3-2, the following bias voltages were measured when the diagnostics were activated in the presence of each of the various faults. The bias point voltages are also given for a situation in which the diagnostics are activated when no fault is present.
| Fault | Speaker Terminal + (V) | Speaker Terminal – (V) | Comparator Output (V) | Outputs |
|---|---|---|---|---|
| Short to GND | 2.43 | 0.017 | 10.79 | 101 |
| Shorted Load | 5.95 | 5.94 | 0.5 | 110 |
| Short to PVDD | 12.03 | 11.73 | 10.85 | 011 |
| Open Load | 11.8 | 0.159 | 10.79 | 001 |
| No Fault | 5.88 | 5.85 | 5.33 | 111 |
Note that the value of the comparator measuring the differential voltage across the speaker terminals is 1 V during low state, as opposed to 0 V for the other two comparators. This is due to the fact that this comparator is actually the second operational amplifier in the LM2904 package, which is configured as a comparator to avoid the need for additional components.
The power consumption of the circuit was also quantified in terms of the amount of current drawn. The measured current draw of the circuit is shown in Table 3-4.
| Diagnostic Circuit State | Typical Current (mA) |
|---|---|
| Active-No Faults | 40 |
| Active-Faults | 36-56 |
| Inactive | 15 |
Note that the values reflect the current drawn for this particular circuit and possibly does not reflect other implementations with resistor values differing from those used in this sample design.