Datasheet

TLE 6368 / SONIC
Data Sheet 8 Rev. 2.2, 2006-12-01
2 Detailed circuit description
In the following major buck regulator blocks, the linear voltage regulators and trackers,
the undervoltage reset function, the watchdog and the SPI are described in more detail.
For applications information e.g. choice of external components, please refer to section
5.
2.1 Buck Regulator
The diagram below shows the internal implemented circuit of the Buck converter, i. e. the
internal DMOS devices, the regulation loop and the other major blocks.
Figure 3 Detailed Buck regulator diagram
The 1.5A Buck regulator consists of two internal DMOS power stages including a current
mode regulation scheme to avoid external compensation components plus additional
blocks for low EME and reduced switching loss. Figure 3 indicates also the principle how
Int. voltage
regulator
Int. charge
pump
Zero cross
detection
Divider
Oscillator
1.4MHz
Slope logic
under-
voltage
lockout
Gate driver
Delay unit
5V 14V
150µA
Vref=6V
Voltage
feedback
amplifier
Current
sense
amplifier
+
Current
comparator
PWM logic
Gate off signal
from overtemp or
sleep command
Trigger for
gate on
Trigger for
gate off
Slope
compensation
Lowpass
Lowpass
switching frequency 330kHz
Slope
control
from
current sensing
to
current sense
amplifier
FB/L_IN
C+
C-
CCP
SLEW
SW
BOOT-
STRAP
BOOST
SW
IN
IN
external components
Main switch ON/OFF
Slope switch
charge signal
Slope switch
discharge signal
8 to 10V
Main
DMOS
Slope
DMOS
pins