CIRCUIT FOR DETERMINING POSITION OF POWER CONTROL BIT

摘要

PURPOSE: A circuit for determining a position of a power control bit is provided to decrease a size of a hardware by using only simple logic circuit without a subtracter. CONSTITUTION: A bit divider(110) divides an N-bit code inputted from the outside into an upper K-bit code and a lower (N-K) bit code. The first adder(120) adds the upper K-bit code and the lower (N-K) bit code. The second adder(130) adds a certain offset to an output of the first adder(120). A logic circuit(140) discriminates whether an output of the second adder(130) is larger than a predetermined value and outputs a discriminating signal. A multiplexer(145) responds to the discriminating signal of the logic circuit(140) and outputs one value as a reference value among at least two values. A down counter(150) receives the output of the second adder(130) and performs a down-count. A comparator(160) discriminates whether a count value of the down-counter(150) is identical to the reference value from the multiplexer(145) and outputs a signal for indicating a position of a power control bit when the count value is identical to the reference value.