4.3
Post-regulator step-up converter Boost1
4.3.1
Functional description Boost1
The device integrates a dedicated step-up converter to generate a 5 V output voltage rail from the Buck1
voltage. The converter uses an asynchronous boost topology with internal low-side switch and an external
diode.
Synchronization of the switching frequency with the other integrated converters as well as an external
synchronization signal is included.
Loop compensation
The integrated loop compensation requires no external components. For information on the selection of the
external components see
.
Overcurrent protection
The integrated overcurrent protection is designed to protect the internal low-side switch of the boost converter.
Due to the nature of the boost topology the boost output rail is not protected against a short circuit directly.
However, indirect protection via an undervoltage protection and current limitation of the front-end converter
Buck1 is available.
Automatic use detection
The integrated automatic use detection allows the system to tell, whether the application uses Boost1. The
device checks the input voltage on the R3FB pin prior to startup of Boost1. If the R3FB pin is connected to the
output voltage of Buck1 through the boost inductor and rectifying diode, then a voltage above the detection
threshold is present at the pin and the device assumes that the application requires Boost1.
stores the result of the detection in order to allow the microcontroller to verify correct detection for the
specific application and differentiate the result from a possible fault present on the PCB.
To indicate to the device that the application does not require Boost1, connect the R3FB pin to R3PG.
OPTIREG
™
PMIC TLF30681QVS01
Power management IC
Power converters and power management
Datasheet
30
Rev. 1.0
2020-04-08
