MAX20070, MAX20070B
Integrated TFT Power Supply and LED Backlight Drivers
Integrated TFT Power Supplies and LED Backlight Driver Reduce System Component
Count
Description
The MAX20070/MAX20070B are highly integrated power supplies and LED backlight
drivers for automotive TFT-LCD applications. The devices integrate one buck-boost
converter, one boost converter, two gate-driver supplies, and a boost/SEPIC converter
that can power one to two strings of LEDs in the display backlight.
The source-driver power supplies consist of a boost converter and an inverting buck-
boost converter that can generate voltages up to +15V and -15V. Both source-driver
power supplies can deliver up to 100mA. The positive source-driver supply regulation
voltage (V
POS
) is set by connecting an external resistor-divider on FBP. Connecting the
FBP pin to ground sets the regulation voltage (V
POS
) to +6.5V. The negative source-
driver supply voltage (V
NEG
) is always tightly regulated to -V
POS
within &plsmn;50mV. The
source-driver supplies use an input voltage from 2.7V to 5.5V to generate the output
voltages.
The gate-driver power supplies consist of regulated charge pumps that generate up to
+22V and -22V and can deliver up to 3mA each. The regulation voltage (V
GVDD
) on the
positive charge pump is set by a resistor-divider on FBPG; the regulation voltage (V
GVEE
)
on the negative charge pump is set by a resistor-divider on FBNG.
The ICs feature a dual-string LED driver that operates off a separate input voltage
(V
BATT
) and can power up to two strings of LEDs with 160mA (max) of current per string.
The startup and shutdown sequences for all power domains is controlled using one of
the seven preset modes that are selectable through a resistor on SEQ.
The MAX20070/MAX20070B are available in a 32-pin, 5mm × 5mm TQFN package with
an exposed pad, and operates over the -40°C to +105°C ambient temperature range.
