PURPOSE: To quicken the operation by feeding back directly a 2nd feedback signal outputted from a 4th transfer gate(TG) of a poststage to 1st and 2nd gate circuits of a pre-stage.
CONSTITUTION: The switching of 3rd and 4th gate circuits 33, 34 is controlled in response to a logic level of a frequency division switching signal, 3rd and 4th TGs 23, 24, the 3rd and 4th gate circuits 33, 34, and 4th and 5th inverters 44, 45 act like a shift register, and a 2nd feedback signal is fed back to 1st and 2nd gate circuits 31, 32. When the 1st, 2nd TGs 21, 22, the 1st and 2nd gate circuits 31, 32 and the 1st and 2nd inverters 41, 42 act like a ring counter, the switching of the 1st and 2nd gate circuits 31, 32 is controlled by a 2nd feedback signal. Thus, the frequency division number is changed in response to a logic level of the frequency division switching signal. Then the 2nd feedback signal outputted from the 4th TG 24 is fed back directly to the internal gate circuits 31, 32 at a high speed.
MORITA YOSHIHIKO
KAWAKAMI YASUSHI
