TLE 4271-2

Data Sheet Rev. 2.4

3

2001-04-04

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

current prevents any over-saturation of the power element.

The reset output RO is in high-state if the voltage on the delay capacitor

C

equal

V

greater than the reset threshold

V

condition’) a fast discharge of the delay capacitor

C

than

V

The time for the delay capacitor charge from

V

When the voltage on the delay capacitor has reached

V

watchdog circuit is enabled and discharges

C

no rising edge observed at the watchdog input,

C

reset output RO will be set to low and

C

V

If the watchdog pulse (rising edge at watchdog input WI) occurs during the discharge

period

C

the periodical behavior starts again.

Internal protection circuits protect the IC against:

• Overload

• Overvoltage

• Overtemperature

• Reverse polarity