| 摘要 |
PURPOSE: A ring oscillator is provided to be capable of conserving a stable frequency state by restraining the change of output frequency according to the ripple of power supply. CONSTITUTION: A ring oscillator is provided with a reference voltage supply part(21) for outputting a constant voltage, a V-I transformation part(22), and an inverter delay cell part(23). The V-I transformation part includes an operational amplifier(27) for receiving the output value of the reference voltage supply part through a non-inverting terminal, an NMOS(N-channel Metal Oxide Semiconductor) transistor connected to the output port of the operational amplifier, a resistor for connecting one terminal of the NMOS transistor with a ground terminal, a current mirror part(26) located between the other terminal of the NMOS transistor and a supply voltage terminal for controlling the level of output current. The inverter delay cell part includes a current magnitude control part(25).
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