| 摘要 |
PURPOSE:To make the capacity of an A/D conversion circuit small and to reduce a cost in a consecutive high-bit A/D converting circuit by combining a low cost arithmetic circuit with a low cost and low bit resolution A/D converter. CONSTITUTION:The titled circuit is provided with a low resolution A/D converter 10, two sets of adder circuits 11, 12 adding the digital outputs of the A/D converter, a triangle wave generator 19 giving a triangle wave having a peak value larger than the minimum resolution of the converter 10 to the analog input 1 of the A/D converter synchronously with the adding period of the adders 11, 12 and a subtraction circuit 13 inverting the analog input and operating the difference of the outputs of the adder circuits 11, 12 corresponding thereto. Then the A/D converter 10 is utilized in terms of PWM (puls width modulation) to the input of a minimum bit of the A/D converter 10 and adds digital outputs of the A/D converter 10 for many number of times. Thus, the A/D conversion with high resolution is attained.
|
