To provide a ring oscillator wherein deterioration of oscillation frequency can be prevented when power source voltage drops, temperature rises and occupied area is small.
The ring oscillator is provided with a ring oscillation part 1 containing a current starvation type inverter CSI which is provided with P-channel transistors P2, P3 and N-channel transistors N3, N2 which are connected in series, and a current control unit 2 which is provided with a basic current source 21 and a current mirror circuit 23. The basic current source 21 contains a p-channel transistor P10 and an n-channel transistor N10 which is operated in a weak inversion state. The current mirror circuit 23 is constituted of a p-channel transistor P12 which is subjected to current mirror connection with the p-channel transistors P10, P2 and an n-channel transistor N12 which is subjected to current mirror connection with the n-channel transistor N2.
| WO/1999/045646 | DEVICE WITH AN OSCILLATOR CIRCUIT |
| WO/2010/073213 | CIRCUIT FOR COMPENSATING INFLUENCE OF TEMPERATURE ON A RESONATOR |
| JPH07202646 | VOLTAGE CONTROLLED OSCILLATION CIRCUIT |
Kawai Nobuaki
Yasuhisa Tanizawa