Evaluates: MAX20070/MAX20070B
MAX20070 Evaluation Kit
General Description
Features
The MAX20070 evaluation kit (EV kit) demonstrates
the MAX20070 IC, which is a highly integrated power
supply plus LED backlight driver for automotive TFT-LCD
applications. The EV kit is a fully assembled and tested
surface-mount PCB that provides a complete power-
management solution for small-size automotive displays.
The EV kit demonstrates one buck-boost converter, one
boost converter, two gate-voltage controllers, and a boost
converter that powers a dual-string LED driver.
● 2.7V to 5.5V Input Range for TFT Power Section
● 4.5V to 16V Input Range for LED Driver Section
● 1MHz Boost and Inverted Buck-Boost Switching
Frequency on TFT Power Section
● TFT Section Output Voltages
• +6.5V Output at 100mA (Step-Up Switching
Regulator)
• -6.5V Output at 100mA (Inverting Buck-Boost
Switching Regulator)
• +16V Output at 3mA (Positive-Charge Pump)
• -7V Output at 3mA (Negative-Charge Pump)
The DC-DC converter portion of the EV kit operates
from a 2.7V to 5.5V DC supply voltage. The step-up
switching regulator (POS) is configured for a 6.5V or 15V
output that provides 100mA. The inverting buck-boost
converter (NEG) generates a negative output that tracks
the positive output and provides 100mA. The gate-driver
power supplies consist of regulated charge pumps that
generate +16V (GVDD) and -7V (GVEE) and can deliver
up to 3mA each. It is also possible to completely turn off
the inverting buck-boost regulator by changing the value
of the R15 resistor to 140kΩ.
● HB LED String Output Currents Configurable for
80mA or 160mA
● Demonstrates Cycle-by-Cycle Current-Limit and
Thermal-Shutdown Features on Boost LED Driver
● Demonstrates Adaptive Voltage Optimization on LED
Driver Section
● Proven PCB Layout and Thermal Design
● Fully Assembled and Tested
The LED driver section demonstrates a step-up DC-DC
preregulator followed by two channels of linear current
sinks. The step-up preregulator switches at 1MHz and
operates as a current-mode-controlled regulator capable
of providing up to 300mA for the linear circuits. Each
channel is capable of operating up to 38V and provides
up to 160mA. The channels are configurable for 80mA or
160mA HB LED output current.
Ordering Information appears at end of data sheet.
The LED driver portion of the EV kit operates from a DC
supply voltage of 4.5V up to the HB LED string-forward
voltage. The EV kit can withstand a 40V load-dump condi-
tion. The EV kit also demonstrates the IC’s features, such
as adaptive voltage optimization, overvoltage protection
(OVP), cycle-by-cycle current limit, thermal shutdown,
and digital PWM dimming operation using a digital PWM
input signal to control the brightness of the HB LEDs.
The EV kit is shipped with the MAX20070, but can also
be used to evaluate the MAX20070B with IC replacement
of U1.
19-7549; Rev 1; 9/15