DELAY TIME CONTROL CIRCUIT

摘要

PURPOSE:To obtain a control circuit with less temperature dependancy and high accuracy and high speed by adopting a constitution so that the base potential of a sawtooth wave is detected by an error amplifier and a switching circuit is controlled by using its detection signal. CONSTITUTION:A sawtooth wave Vcomp is generated by the same operation as that of a conventional method. An error amplifier 6 sets a potential VB deciding a base potential to one input terminal, the wave Vcomp to be controlled is inputted to the other input terminal and its base potential is limited to the potential VB. The output of the amplifier 6 is inputted to the base of a transistor (TR) Q2 constituting a switching circuit to control the circuit to prevent its over-saturation. The sawtooth wave Vcomp obtained in this way enters a camparator 3 and compared with a comparison voltage level VREF proper to obtain a delay time td, thereby obtaining an output pulse Vout. The pulse Vout is retarded from the original signal Vin by the time td. Thus, the sawtooth wave with high accuracy is obtained and the base potential is decided uniquely by the voltage VB subjected to temperature compensation. Moreover, high speed operation is obtained.