| 摘要 |
<p>PROBLEM TO BE SOLVED: To regulate the voltage level to be monitored correctly by inverting the output state when a charged voltage reaches a predetermined level and latching the output signal thereof and the resetting a latch means until the charged voltage reaches the predetermined level. SOLUTION: In a monitor voltage detection means 120, an NMOS transistor NM1 is turned on when the charged voltage reaches a level Vgs(NM1)+2Vt (Vt: threshold value) and the potential at node N2 drops from VCC to 2Vt. Consequently, setting of monitor voltage can be regulated by the number of transistors to be connected in series. Potential at node N4 is held at VCC until the charged voltage reaches the state transition point of an inverter G1 and an NMOS transistor NM4 is turned on. Consequently, a potentialϕVCCH goes low and a latch means 130 is reset. When the charged voltage exceeds the transition point, the node N4 goes low and the NMOS transistor NM4 is turned off and the output from the monitor voltage detection means 120 is latched by the latch means 130 when the monitor voltage is reached.</p> |
