TLF51801ELV Datasheet, PDF (18/29 Pages) Infineon Technologies AG – 10 A synchronous DC/DC Step-Down Controller

TLF51801ELV
Linear Regulator
7
Linear Regulator
7.1
Description
The internal linear voltage regulator supplies the low-side gate driver directly (typical voltage 5.4 V) and through
a diode the high-side gate driver. The current capability is up to 50 mA. An external output capacitor with low ESR
is required on pin IVCC for stability and buffering transient load currents. During normal operation the gate drivers
will draw transient currents from the linear regulator and its output capacitor. Proper sizing of the output capacitor
must be considered to supply sufficient peak current to the gate of the external MOSFETs. An integrated power-
on reset circuit monitors the linear regulator output voltage and resets the device in case the output voltage falls
below the power-on reset threshold. The power-on reset helps protect the external MOSFETs from excessive
power dissipation by ensuring the gate drive voltage is sufficient to enhance the gate of an external logic level n-
channel MOSFET. For IVCC voltage lower than 5V the proper charging of the bootstrap capacitor is not
guaranteed.
The internal linear voltage regulator is implemented to supply the gate drivers, therefore a large voltage ripple may
be present on this output due to the pulsed current sinked by internal drivers and bootstrap diode. This output
should not be used to supply loads than the internal ones.
VS
1
EN
2
Linear Regulator
IVCC
3
HS Gate
Driver
LS Gate
Driver
Figure 11 Linear Regulator Block Diagram and Simplified Application Circuit
Data sheet
18
Rev. 1.0.1, 2013-04-15