Data Sheet

4

Rev. 2.8, 2007-03-20

TLE 4263

Circuit Description

The control amplifier compares a reference voltage, which is kept highly accurate by

resistance adjustment, to a voltage that is proportional to the output voltage and drives

the base of the series transistor via a buffer. Saturation control as a function of the load

current prevents any over-saturation of the power element. If the externally scaled down

output voltage at the reset threshold input drops below 1.35 V, the external reset delay

capacitor is discharged by the reset generator. When the voltage of the capacitor

reaches the lower threshold

V

until the upper threshold

V

GND, reset is triggered at an output voltage of typ. 4.65 V. A connected microcontroller

will be monitored through the watchdog logic. In case of missing pulses at pin W, the

reset output is set to low. The pulse sequence time can be set in a wide range with the

reset delay capacitor. The IC can be switched at the TTL-compatible, low-active inhibit

input. The IC also incorporates a number of internal circuits for protection against:

•

Overload

•

Overtemperature

•

Reverse polarity

Figure 2

Block Diagram

Input

AEB03068

INH

GND

Output

D

RO

RADJ

Reset

Delay

Reset

Output

Reset

Threshold

Watchdog

W

Temperature

Sensor

Generator

Reset

Reference

Bandgap

Adjustment

Buffer

Control

Amplifier

Saturation

Control and

Protection

Circuit

Inhibit

Ι

Q

GND