To sufficiently components the influence of temp. in the temp. coefficient of an oscillation frequency by setting the current density of a reference diode to be lower than the that of a clamp diode and generating the temp. coefficient of the reference diode more largely.
When slight current is permitted to flow between a control input terminal 1 and a ground with starting resistance, the current is supplied to the composite circuit of the input TRs Q7 and Q8 of an oscillator 10 with the transistors TRs Q14 and Q15 off a current mirror stage and the operation current of the oscillator is supplied to TRs Q5 and Q6 constituting a constant current circuit. The current is permitted to flow through reference diodes Q91-Q9n so as to generate a forward lowering voltage VD. A differential voltage AMP amplifies the difference voltage between the forward lowering voltage VD and the terminal voltage of resistance R3, thereby current is permitted to flow through resistance R3 is increased through TR Q12 and Q13 so that the difference voltage becomes zero. Thus, the current density of the reference diode is set to be lower than that of the clamp diode so that the temp. coefficient of the reference diode is generated more largely.
KATO KAZUO
TOMITA KIKUO
