34704_09 Datasheet, PDF (25/49 Pages) Freescale Semiconductor, Inc – Multiple Channel DC-DC Power Management IC

FUNCTIONAL DESCRIPTION
FUNCTIONAL INTERNAL BLOCK DESCRIPTION
• Output voltage is adjustable by means of an external
resistor divider when in voltage regulation mode
• A 240mV current limit comparator will be used to program/
sense the voltage drop across the current setting resistor
at the bottom of the LED string connected to the REG8
output when the current regulation mode is selected.
This will be used to program the maximum current flowing
and will regulate it
• The output can be adjusted up or down at 2.5% steps for
a total of 10% on each direction allowing Dynamic Voltage
Scaling
• Maximum output current is adjustable by means of an
external resistor connected to the FB8 pin and then the
output current can be scaled down from the set maximum
in 16 steps through I²C interface
• Uses a bootstrap network with an internal diode to power
its synchronous MOSFET
• All gate drive circuits are supplied from VG.
• Uses integrated compensation
• The output is monitored for over-current and short-circuit
conditions
• The regulator is monitored for over-temperature conditions
• The output is monitored for under-voltage and over-
voltage conditions
Operation Modes
The switchers will be active when:
• VG is in regulation AND
• There is no GrpD shutdown command through the I²C
interface AND
• No faults exist that would cause GrpD to shut down
Analog Integrated Circuit Device Data
Freescale Semiconductor
34704
25