Transducer Built-In Self-Test

An apparatus for testing a transducer module having a plurality of transducers, the plurality of transducers having a common-mode terminal, each transducer configured to independently produce corresponding output signal relative to the common-mode terminal in response to a common stimulus, the apparatus comprising:

• a test signal generator configured to generate an alternating test signal having a test signal amplitude, the test signal generator having a test signal output terminal configured to provide the test signal from the test signal generator a the common-mode terminal of the transducer module;
• a signal processing circuit configured to process transducer output signals from a transducer module, the signal processing circuit having an interface comprising:
• a first signal processing input terminal configured to receive a first transducer output;
• a second signal processing input terminal configured to receive a second transducer output;
• a signal processing circuit output configured to produce a system output signal based on the first transducer output and the second transducer output;
• a controller configured to controllably couple the test signal to the common-mode terminal of the transducer module in a test mode;
• and
• an output comparator coupled to receive the system output signal and configured to produce, in the test mode, a comparator output signal indicating that the system output signal indicates a mismatch between the first transducer and the second transducer.

An apparatus for testing a transducer module having a first transducer and a second transducer, the first transducer and the second transducer having a common-mode terminal, each of the first transducer and the second transducer configured to independently produce corresponding first and second output signal, relative to the common-mode terminal, in response to a common stimulus applied to the first transducer and the second transducer, the means comprising:

• means for generating a test signal;
• means for processing transducer output signals from the transducer module to produce a transducer module output signal;
• means for controllably providing the test signal to the common-mode terminal, in a test mode;
• and
• means for producing, in the test mode, a mismatch output signal indicating that the transducer module output signal indicates a mismatch between the first transducer and the second transducer.