Patent ID: 6639539
Filing Date: 2003-10-28
Classification: H03M

Abstract:
A system for improving the dynamic range of an A/D converter, comprising: an analog summing amplifier having first and second input terminals of opposite polarity and an output terminal which is connected to the input of the A/D converter; means for applying an analog input signal to the first input terminal; a feedback resistor connected between the output terminal and the first input terminal; means for applying a voltage VCC/2 to the second input terminal; first and second resistors of equal value connected to the first input terminal; and means for monitoring operation of the A/D converter and connecting the first resistor to VCC and the second resistor to 0 volts when the A/D converter is operating within its dynamic range, connecting both the first resistor and the second resistor to VCC when the A/D converter reaches the upper limit of its dynamic range, and connecting both the first resistor and the second resistor to 0 volts when the A/D converter reaches the lower limit of its dynamic range.