TRIANGULAR WAVE SIGNAL GENERATING CIRCUIT

摘要

PURPOSE:To generate a prescribed triangular wave signal by controlling the current value of charging current source by an outputted error signal and at the same time controlling the duty of an input clock signal. CONSTITUTION:A clock signal is inputted to a triangular wave signal generating part 6, and at the same time the value of the charging and discharging currents flowing to a capacitor C1 are equal to each other. Then the charging and discharging modes are switched by a Q8 and a triangular wave signal is generated. The triangular wave signal is inputted to the comparators 8 and 11 respectively via a buffer 7. Then the output of a charge pump circuit 12 generates a peak error signal by a peak error generating circuit 13 and controls the charging/ discharging value of the part 6. Meanwhile the input of a charge pump circuit 9 generates an offset error signal by an offset error generating circuit 10 and inputs this error signal to a variable pulse delay circuit 3 to vary the pulse delay time. Thus the clock duty is controlled.