| 摘要 |
PURPOSE:To realize an oversampling type A/D converter realizing a stable conversion characteristic against manufacture tolerance of components with low power consumption against a wide range of power supply voltage condition including an operating condition at a low power supply voltage. CONSTITUTION:A difference between output currents Isig, Iq of voltage /current conversion circuit 101 and a current switch circuit in an oversampling A/D converter employing the current switch circuit 102 as a local D/A converter is integrated by a capacitor 105 whose one terminal connects to a DC level VB. Moreover, multi-bit processing is adopted for the current switch circuit 102 to decrease the difference between the signal current Isig and a feedback current signal Iq. Furthermore, the DC component is reduced apparently from the input analog signal Vsig using an internal generating DC voltage as a DC bias voltage by the level shift function of the voltage/current conversion circuit 101 itself to reduce a change in a voltage between the electrodes of the capacitor due to the current integration.
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