MB3793-45

4

DS04-27405-2E

■ BLOCK FUNCTIONS

1.

Comp. S

This function enables the MB3793 to detect an abnormality within 1

μs when the power is cut or falls abruptly.

2.

Output circuit

The output circuit has a comparator to control the reset signal (RESET) output. When the voltage at the CTP

pin for setting the power-on reset hold time exceeds the threshold voltage, resetting is canceled.

Since the reset (RESET) output buffer has the CMOS organization, no pull-up resistor is needed.

3.

Pulse generator

The pulse generator generates pulses when the voltage at the CK1 and CK2 input clock pins changes to High

from Low level (positive-edge trigger) and exceeds the threshold voltage; it sends the clock signal to the watchdog

timer.

4.

Watchdog timer

The watchdog timer can monitor two clock pulses. Short-circuit the CK1 and CK2 clock pins to monitor a single

clock pulse.

5.

Inhibition pin

The inhibition (INH) pin forces the watchdog timer on/off. When this pin is High level, the watchdog timer is

stopped.

6.

Logic circuit

of Comp.S and Watchdog timer.