Patent attributes
A volume circuit contains resistive ladder circuits, from which a desired fractional voltage output (Vs) is extracted and supplied to an amplifier to provide an output voltage (Vout). The resistive ladder circuits comprise multiple lines of series resistances, wherein each line contains a resistance portion ‘nR’ (where ‘n’ denotes a division index, and ‘R’ denotes an element resistance) that is connected in parallel with a next line, so that an overall resistance of following lines is ‘(n−1)×n’ times larger than the element resistance. Secondary resistive ladder circuits can be additionally arranged in series in order to control a secondary amplifier that absorbs excessive currents flowing into the resistive ladder circuits. The secondary resistive ladder circuits are constituted symmetrically with the resistive ladder circuits, in which output terminals (t1-t12) are all set to the same potential.
