DELAY TIME CONTROL CIRCUIT

摘要

PURPOSE:To generate a stable sawtooth wave and to apply the control of a delay time with high accuracy, by providing an error amplifier which inputs a pair of pulse signals with phases opposite to each other to both bases of an emitter-coupling balanced switching circuit and furthermore, controls the base potential of the sawtooth wave at a constant level. CONSTITUTION:When an original signal pulse inputted to an input terminal 1 is set at an 'b', and a signal pulse inputted to an input terminal 7 on the other side at an 'H', a transistor Q1 is turned 'OFF', and a transistor Q2 is turned 'ON'. In such a state, a constant current is charged from a constant current source 2 to a recharging capacitor C, then, the sawtooth wave is generated. Next, when the original signal pulse goes to the 'H' and the pulse with opposite phase on the other side goes to the 'L', discharging is performed to the constant level with the supplying current value of a constant current source 5, Then, the error amplifier 6 compares it with a reference voltage VB on one side, and controls the base of a transistor Q3 so as to suppress the base potential of the sawtooth wave at the VB. Therefore, it is possible to obtain the sawtooth wave with high accuracy, and the base potential of the sawtooth wave is controlled at a constant value by the reference voltage VB on which temperature compensation is applied.