TIMER CIRCUIT AND SEMICONDUCTOR MEMORY INCORPORATING THE TIMER CIRCUIT

摘要

A timer circuit exhibiting a timer period which decreases with a rise of temperature and increases with a fall of temperature. A diode (D) has a current characteristic depending on temperature. The forward current flow through an n-type MOS transistor (N1) constituting the primary side of a current mirror. Depending on the current flowing through the n-type MOS transistor (N1), the current flowing through a p-type MOS transistor (P2) and an n-type MOS transistor (N3) constituting the secondary side of the current mirror is determined. The current flowing through the p-type MOS transistor (P2) and the n-type MOS transistor (N3) is supplied as the operating current of a ring oscillator constituted of inverters (I1-I3). Therefore, the period (timer period) of a clock signal CLK outputted from the ring oscillator reflects the temperature characteristics of the diode (D), and the timer period decreases with a rise of temperature.