TLE6363 Datasheet, PDF (16/28 Pages) Infineon Technologies AG – Multifunctional Voltage Regulator and Watchdog

TLE 6363
Boost Converter
The TLE 6363 contains a fully integrated boost converter (except the boost-diode),
which provides a supply voltage for an energy reserve e.g. an airbag firing system. The
regulated boost output voltage V_BOOST is programmable by a divider network (external
resistors) providing the feedback voltage for the boost feedback pin BOFB. The energy
which is stored in the external electrolytic capacitor at V_BOOST guarantees accurate
airbag firing, even if the battery is disconnected by a car crash.
The boost inductance L_BO (typ. 100 ←H) is PWM-switched by an integrated current
limited power DMOS transistor with a programmable (external resistor R_R) frequency.
An internal bandgap reference provides a temperature independent, on chip trimmed
reference voltage for the regulation loop. An error amplifier compares the reference
voltage with the boost feedback signal V_BOFB from the external divider network
(determination of the output boost voltage V_BOOST).
Application note for programming the output voltage at pin V_BOOST:
V_BOOST
=
V_BOFBTH
⌠
Ε_---R_{----B---O----1---+-----}R_{-----B---O---2---}Φ
R_BO2
With a PWM (Pulse Width Modulation) comparator the output of the error amplifier is
compared to a periodic linear ramp, provided by a sawtooth signal of the oscillator
connected to pin R. A logic signal with variable pulse width is generated. It passes
through the logic circuits (sets the output latch PWM-FF) and driver circuits to the power
switching DMOS. The Schmitt-trigger output resets the output flip-flop PWM-FF by
NOR 2. The PWM signal is gated by the NAND 2 to guarantee a dominant reset.
Data Sheet V 1.1
16
2000-11-8