| 摘要 |
PURPOSE:To obtain a circuit limiting no range in operation power source voltage and lowering no reliability by processing power sourc voltage by a boosting circuit and a step-down circuit according to external source voltage and supplying it to an internal circuit. CONSTITUTION:The external source voltage is converted to low voltage PHI1 by a voltage conversion circuit 11 and compared with the reference voltage PHI2 of a reference voltage generation circuit 12 by a step-down/boosting selection circuit 13. In accordance with the compared result, the step-down circuit 14 or the boosting circuit 15 is selected, step-down and boosting are controlled constantly. Furthermore, an internal voltage limiting circuit 16 compares the output voltage of circuits 14, 15 with the reference voltage from the circuit 12. and voltage supplied to the internal circuit 17 is held constantly. Then, the semi-conductor integrated circuit limiting no range in operation power source voltage and lowering no reliability is obtained. |
