| 摘要 |
<p>PURPOSE:To prevent an operating margin from reduction even in a low voltage area by obtaining the reference voltage of an internal voltage dropping power supply circuit with a signal which is internally boosted with an oscillator. CONSTITUTION:The power supply circuit is provided with an oscillator 20 consisting of a ring oscillator, etc., and a charging pump consisting of transistors Q21, Q22, and a capacitance C1. A boosted signal is supplied to a reference voltage generation part. The reference voltage Vref is obtained from one connecting point of a series of transistors Q11-Q15. In such a manner, even when an external power supply voltage is dropped, a constant voltage is always kept and the semi-conductor memory whose operating margin is not reduced even in a low voltage area is obtained.</p> |
