| 摘要 |
PROBLEM TO BE SOLVED: To achieve low voltage operation of a voltage controlled oscillating circuit. SOLUTION: Controlling transistors TC1 to TC3 comprising N-channel MOS transistors are connected between a connecting point between drains of both transistors constituting CMOS inverters IN1 to IN3 and grounding potential, and a control voltage VC is applied to gates of the TC1 to TC3. By this, a controlling current Id is made to flow through the TC1 to TC3, which results in varying the inverter current If flowing through the IN1 to IN3, and oscillation frequencies of oscillation output varies. Since the TC1 to TC3 are connected between the connecting point between the drains of both transistors constituting the IN1 to IN3 and grounding potential, the low voltage operation can be achieved as compared when the T1 to TC3 are connected in series with the IN1 to IN3.
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