| 摘要 |
The ring oscillator circuit with the current mirror type current limit circuit of this invention prevents the malfunction and the halt of the ring oscillator. The ring oscillator is configured with the serially connected CMOS inverters INV 1 -INV 5 where the output of the last CMOS inverter INV 5 is fed back to the input of the first CMOS inverter INV 1 . Also, the current mirror type current limit circuit for controlling the electric current going through the CMOS inverters INV 1 -INV 5 is formed. The first supporting transistor T 1 that helps the output of the CMOS inverter INV 5 achieve the full-swing for reaching the power supply voltage Vdd and the second supporting transistor T 2 that helps the output of the CMOS inverter INV 5 achieve the full-swing for reaching the ground voltage Vss according to the output of the CMOS inverter INV 3 two positions ahead of the last inverter INV 5 are also formed.
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