TLE4471_09 Datasheet, PDF (15/24 Pages) Infineon Technologies AG – Triple Voltage Regulator

TLE 4471
Output Voltage
To obtain an output voltage of V_Q1 = 5 V with an accuracy of 2% at the main output Q1
an input voltage in the range of 5.5 V < V_I < 40 V is needed. The main output Q1 supplies
5 V with 450 mA current capability. For stability it requires an output capacitor of at least
22 µF and a maximum ESR of 3 Ω. The two outputs Q2 and Q3 are tracked to Q1 and
can supply currents of 100 mA and 50 mA. So any undervoltage condition or shutdown
of Q1 will cause the same effect to Q2 and Q3. For Stability both outputs require an
output capacitor of at least 10 µF with ESR < 3 Ω each. Q2 is switched on and off
simultaneously with Q1, while the tracked output Q3 can be enabled or disabled
individually.
Two reference outputs REF2, REF3 with voltages of V_REF2 = V_Q2/2 and V_REF3 = V_Q3/2 are
also available. In case of an overvoltage at the tracker outputs, the voltage references
are limited internally to 4.5 V.
Output Current
The output current is a function of the input voltage. For high input voltages above 22 V,
the output current is reduced linear. This is designed into the regulator for protection.
Above 42 V the regulator is switched off. The thermal shutdown switches the regulator
off, if it exceeds the thermal threshold of 160 °C typical. It is switched on again, as soon
as the regulator is cooled down by typical 10 K (thermal hysteresis). Please note the
device should not be operated above a junction temperature of 150 °C for long term
reliability.
Enable Function
The TLE 4471 includes the possibility of enabling the main and tracked outputs.
Three ORed enable inputs E1, E2, E3 are used to control the main output Q1 and the
tracked output Q2. E1 and E3 can be supplied from the battery line or ignition key with
input voltages up to 16 V. The enable inputs should be protected by a series resistor and
a capacitor, e.g. R_E1 = R_E3 = 22 kΩ, C_E1 = C_E3 = 2.2 nF. E2 is intended for connection to
the microcontroller. A logic HIGH at any enable input will switch on the related regulator
and/or tracker.
A separate enabling pin EN is available to switch on and off the second tracked output
Q3 separately by the microcontroller.
Reset
The power on reset feature is necessary for a defined start of the microprocessor during
power up. When the output voltage of the main regulator has reached the reset threshold
voltage the reset delay capacitor C_DR is charged. After a certain time, the reset delay time
t_dr, the voltage at the capacitor equals the upper reset timing threshold and the reset
output goes HIGH.
Data Sheet
15
Rev. 1.6, 2009-02-03