Datasheet

2

Rev. 1.1, 2007-10-17

TLE 4299

Circuit Description

The TLE 4299 is a PNP based very low drop linear voltage regulator. It regulates the

output voltage to

V

circuit protects the device against potential damages caused by overcurrent and

overtemperature.

The internal control circuit achieves a 3.3 V output voltage with a tolerance of

± 2%.

The device includes a power on reset and an under voltage reset function with adjustable

reset delay time and adjustable reset switching threshold as well as a sense control/early

warning function. The device includes an inhibit function to disable it when the ECU is

not used for example while the motor is off.

The reset logic compares the output voltage

V

voltage drops below this level, the external reset delay capacitor

C

V

very short, the

V

avoids resets at short negative spikes at the output voltage e.g. caused by load changes.

As soon as the output voltage is more positive than the reset threshold, the delay

capacitor is charged with constant current. When the voltage reaches

V

output RO is set High again.

The reset delay time and the reset reaction time are defined by the external capacitor

C

In addition to the normal reset function, the device gives an early warning. When the SI

voltage drops below

V

and the

µ-processor that this voltage has dropped. The sense function uses a hysteresis:

When the SI-voltage reaches the

V

used as early warning function to notice the

µ-controller about a battery voltage drop and

a possible reset in a short time. Of course also any other voltage can be observed by this

feature.

The user defines the threshold by the resistor-values

R

For the exact timing and calculation of the reset and sense timing and thresholds, please

refer to the application section.