Avalanche 800 IQ & 1200 IQ Technology
Each bridged power amplifier module has a 32-bit microcontroller (MCU) for control and monitoring purposes. This MCU communicates with the Digital Front-End.
The power amplifier module MCU utilizes 5 channels of A/D (analog to digital) conversion to monitor the following parameters in real time at a rate of 1000 samples/second:
- The output voltage of amplifier A and B (the two halves of the bridged amplifier)
- The power supply rails (positive and negative voltages)
- The module temperature sensor
By monitoring these parameters and the over-current detector, fault conditions can be detected immediately and lead to immediate shutdown of the amplifiers.
Safety and Reliability
Certain strategies are employed to increase the safety margin and reliability: For example, the power supply rail voltages are measured before the power amplifiers are activated. If either rail voltage is outside the normal limits, the amplifiers are not activated and the power supply will be shut down. Since this is a bridged amplifier, the output voltages of both amplifiers should always be equal and opposite (A+B=0).
If a fault condition occurs in either amplifier, the MCU can detect it within 1 millisecond (1/1000 of a second, ms) and shut down the amplifiers. A typical single-ended power amplifier with an analog offset detection circuit must have a long time constant (> 100ms) in order to distinguish between DC and a low frequency signal.
All of the parameter margins (limits) are part of the digital front-end firmware. They are downloaded to the amplifier module(s) at power on. In the case of any fault condition, the power amplifier MCU informs the digital front-end MCU and adds the specific fault information.
The strategy for each error type is determined by the digital front-end MCU firmware. For example, in the event of an overcurrent condition, the amplifier can be restarted with a limit on the number of restarts.
To simplify troubleshooting, the digital front-end MCU displays the error information on the LCD in case of a fault condition.
The power amplifier MCU also stores statistical information that can be used in various ways: Number of clipping events, maximum and minimum values for all monitored parameters (such as max/min rail voltages). This is crucial for the Arendal Sound engineers to understand if there are any problems or strange behaviour of the amplifier.
The digital front-end can run a complete self-test of the entire system. This includes generating a test tone and measuring the amplifier output voltages and all other parameters. Any failure is displayed on the LCD screen.
ROHS, FCC and CE certified.