TLE6363_03 Datasheet, PDF (19/28 Pages) Infineon Technologies AG – Multifunctional Voltage Regulator and Watchdog

TLE 6363
Buck Converter
A stabilized logic supply voltage (typ. 5 V) for general purpose is realized in the system
by a buck converter. An external buck-inductance L_BU is PWM switched by a high side
DMOS power transistor with the programmed frequency (pin R).
The buck regulator supply is given by the boost converter output V_BOOST, in case of a
battery power-down the stored energy of the boost converter capacitor is used.
Like the boost converter, the buck converter uses the temperature compensated
bandgap reference voltage (typ. 2.8 V) for its regulation loop.
This reference voltage is connected to the non-inverting input of the error amplifier and
an internal voltage divider supplies the inverting input. Therefore the output voltage V_CC
is fixed due to the internal resistor ratio to typ. 5.0 V.
The output of the error amplifier goes to the inverting input of the PWM comparator as
well as to the buck compensation output BUC.
When the error amplifier output voltage exceeds the sawtooth voltage the output power
MOS-transistor is switched on. So the duration of the output transistor conduction phase
depends on the V_CC level. A logic signal PWM with variable pulse width is generated.
Data Sheet Rev. 1.2
19
2003-06-02