ABRIDGED DATA SHEET
EVALUATION KIT AVAILABLE
MAX20078
Synchronous Buck,
High-Brightness LED Controller
General Description
Benefits and Features
The MAX20078 is a high-voltage, synchronous n-channel
MOSFET controller for high-current buck LED drivers. The
device uses a proprietary average current-mode-control
scheme to regulate the inductor current. This control
method does not need any control-loop compensation
while maintaining nearly constant switching frequency.
Inductor current sense is achieved by sensing the
current in the bottom synchronous n-channel MOSFET. It
does not require any current sense at high voltages. The
device operates over a wide 4.5V to 65V input range. The
device is designed for high-frequency operation and can
operate at switching frequencies as high as 1MHz. The
high- and low-side gate drivers have peak source and sink
current capability of 2A. The driver block also includes
a logic circuit that provides an adaptive nonoverlap time
to prevent shoot-through currents during transition. The
device includes both analog and PWM dimming. The
● Automotive Ready: AEC-Q100 Qualified
● Wide Input Voltage Range: 4.5V to 65V
● Easy to Design
• No Compensation Components
• Programmable Switching Frequency
● Wide Dimming Ratio Allows High Contrast Ratio
• Analog Dimming
• PWM Dimming
● Suitable for Matrix Lighting
• Maintains Current Regulation While Shorting/
Opening Individual LEDs in the String
• Ultrafast-Response Control Loop Prevents
Overshoots and Undershoots
● Fault Detection and Protection
• Overvoltage Protection
• Open and Short Detection
• Low-Power Shutdown Mode
• Thermal Shutdown
device includes a 5V V
regulator capable of delivering
CC
10mA to external circuitry. The device also includes a
current monitor that provides an analog voltage
proportional to the inductor current. The device has
a fault flag that indicates open and shorts across the
output. Protection features include inductor current-limit
protection, overvoltage protection, and thermal shutdown.
The MAX20078 is available in a space-saving (3mm x
3mm), 16-pin TQFN or a 16-pin TSSOP package and is
specified to operate over the -40°C to +125°C automotive
temperature range.
• Inductor Current Monitor
Applications
● Automotive Front Lights
● Automotive Matrix Lights
● Head-Up Displays
● Constant-Current Regulators
Ordering Information appears at end of data sheet.
Simplified Schematic
INPUT
C
IN
C
VCC
D1
V
BST
CC
R1
IN
DH
Q1
C
BST
MAX20078
L1
TON
LX
DL
C1
C
OUT
R2
R3
Q2
LED1
LEDn
PWM
DIM
LED CURRENT CONTROL
REFI
CSP
FAULT FLAG
R
CS
FLT
CSN
OUT
CURRENT MONITOR
IOUTV
PGND
AGND
19-8717; Rev 4; 7/18