Chapter 1 Overview

1-6-3 Power Supply

„The Relation between Power Supply and Input Pin Voltage

Input pin voltage should be supplied only after power supply is on. If the input pin voltage is applied supplies before power supply is on, a latch up occurs and causes the destruction of micro controller by a large current flow.

Input

Input protection resistance

P

Forward current generates

N (VDD)

Figure 1-6-4 Power Supply and Input Pin Voltage

„The Relation between Power Supply and Reset Input Voltage

After power supply is on, reset pin voltage should be low for sufficient time, ts, before rising , in order to be recognized as a reset signal.

Power voltage

Voltage

Reset Input Voltage

Reset pin low level

0

Time

t

ts

[ Chapter 2. 2-8 Reset ]

Figure 1-6-5 Power Supply and Reset Input Voltage

Precautions I - 31

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Image 49
Panasonic F77G, MN101C77C user manual Power Supply, Reset Input Voltage Reset pin low level Time