Abstract: An electronic device includes a pixel array having a plurality of rows with active imaging pixels, and at least one row with test pixels. Each of the test pixels includes a test voltage generation circuit generating a test voltage, a switching circuit receiving the test voltage and an image pixel output signal and passing the test voltage as output when in a test mode, a comparison circuit receiving the output from the switching circuit and an analog to digital conversion signal and asserting a counter reset signal when the output from the switching circuit and the analog to digital conversion signal are equal in voltage, and a counter beginning counting at a beginning of each test cycle within the test mode, stopping counting upon assertion of the counter reset signal, and outputting its count upon stopping counting. The count is proportional to the test voltage when in the test mode.

Abstract: An electronic device includes a test voltage generation circuit to generate a test voltage as a function of a regulator voltage, and a switching circuit to receive the test voltage and an image pixel output signal, and to pass the test voltage as output when in a test mode. A comparison circuit receives the output from the switching circuit and an analog to digital conversion signal, and asserts a counter reset signal when the output from the switching circuit and the analog to digital conversion signal are equal in voltage. A counter begins counting at a beginning of each test cycle within the test mode, stops counting upon assertion of the counter rest signal, and outputs its count upon stopping counting. The count is proportional to the test voltage when in the test mode.

Abstract: An electronic device includes a test voltage generation circuit to generate a test voltage as a function of a regulator voltage, and a switching circuit to receive the test voltage and an image pixel output signal, and to pass the test voltage as output when in a test mode. A comparison circuit receives the output from the switching circuit and an analog to digital conversion signal, and asserts a counter reset signal when the output from the switching circuit and the analog to digital conversion signal are equal in voltage. A counter begins counting at a beginning of each test cycle within the test mode, stops counting upon assertion of the counter rest signal, and outputs its count upon stopping counting. The count is proportional to the test voltage when in the test mode.

Abstract: Disclosed is keypad circuitry operable to detect a pressed key while reducing electromagnetic interference (EMI). The keypad circuitry is operable to reduce EMI in two ways: a) reducing the voltage swing occurring at the row circuitry and column circuitry of the keypad, and b) reducing the number of signal transitions by restricting the signal transitions to occurring at the column and row corresponding to a pressed key. By limiting signal transitions to occurring only at the row and column corresponding to a pressed key, fewer signal transitions occur, and thus, less EMI is produced. Additionally, reduced voltage swings at the row circuitry and column circuitry results in reduced EMI.

Abstract: Disclosed is keypad circuitry operable to detect a pressed key while reducing electromagnetic interference (EMI). The keypad circuitry is operable to reduce EMI in two ways: a) reducing the voltage swing occurring at the row circuitry and column circuitry of the keypad, and b) reducing the number of signal transitions by restricting the signal transitions to occurring at the column and row corresponding to a pressed key. By limiting signal transitions to occurring only at the row and column corresponding to a pressed key, fewer signal transitions occur, and thus, less EMI is produced. Additionally, reduced voltage swings at the row circuitry and column circuitry results in reduced EMI.