TLE 4299

Datasheet Rev. 1.0

2

2005-01-27

Circuit Description

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

voltage to

V

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

drops below this level, the external reset delay capacitor

C

V

is not reached and no reset-signal is asserted. This feature 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

again.

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

C

function is active down to

V

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

drops below

V

that this voltage has dropped. The sense function uses a hysteresis: When the SI-voltage reaches

the

V

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.