DUAL-MODULUS PRESCALER CIRCUIT OPERATING AT A VERY HIGH FREQUENCY

摘要

ABSTRACT DUAL-MODULUS PRESCALER CIRCUIT OPERATING AT A VERY HIGH FREQUENCY The dual-modulus prescaler circutt (1) is devised to operate at a very high frequency. This circuit includes an assembly formed of two dynamic D-type flip flops (12, 13), and two NAND logic gates (15, 16) arranged in negative feedback between the two flip flops. The two flip flops are clocked by an input clock signal (CK) to supply a divided output signal (OUT) whose frequency matches the input clock frequency divided by 2 or by 3 as a function of a division mode selection signal (divb) applied to the input of the first NAND logic gate (15). One non-inverted output of the second flip flop is connected to one input of the first tllp flop (12). The first dynamic flip flop includes three active branches and supplies a single inverted output signal. A third flip flop (14) with three active branches receives an inverted mode selection signal (div) at input in order to supply the mode selection signal to the inverted output thereof, clocked by the non-inverted output signal of the second flip flop. Figure 2