MAX8901B Maxim Integrated Products, MAX8901B Datasheet - Page 9

• Manufacturer Part Number: MAX8901B
• Description: Highest Efficiency Supply
• Manufacturer: Maxim Integrated Products

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The MAX8901_ features:
•
•
•
•
No WLED current is present in shutdown or during an
overvoltage condition if the WLED forward voltage is
greater than the input supply voltage. Figures 2 and 3
show the block diagrams for the MAX8901A and
MAX8901B, respectively.
Figure 3. MAX8901B Block Diagram
Series WLEDs in a 2mm x 2mm TDFN Package
Internal soft-start that gradually illuminates the
WLEDs to eliminate inrush current during startup.
Input overvoltage protection (6.5V max) that
prevents IC switching when exceeded.
WLED overvoltage protection (25V typ) that latches
off the IC.
Shutdown mode that reduces current to 0.01µA (typ).
_______________________________________________________________________________________
Highest Efficiency Supply for 2 to 6
SHUTDOWN
SHUTDOWN
750kHz OSC
MAX8901B
THERMAL
INTERNAL
TIMER
Gm
EP
0.5V
CONTROL
BOOST
LOGIC
REF
When V
lockout (OVLO) is engaged to protect the MAX8901_
from high-input voltage conditions. Once input OVLO
occurs, the MAX8901_ stops switching and no WLED
current flows, provided the forward voltage of the
WLED string is greater than V
6V (min), the input OVLO condition is cleared, and the
IC is enabled and enters soft-start.
WLED overvoltage protection (OVP) occurs when the
WLED output voltage rises above the WLED OVP
threshold. The WLED OVP protection circuitry latches
off the IC and the IC enters shutdown when the WLED
OVP threshold is exceeded. After OVP is engaged,
cycle V
soft-start.
DIMMING
PULSE
IN
IN
or toggle ON to reenable the IC and enter
exceeds 6.2V (min), input overvoltage
POWER
IC
WLED Overvoltage Protection
COMP
PGND
GND
OVP
CS
LX
ON
IN
Input Overvoltage Lockout
IN
. When V
IN
falls below
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