AT9933
Hysteretic Boost-Buck (Ćuk) LED Driver IC
Features
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Constant current LED Driver
Steps input voltage Up or Down
Low EMI
Variable frequency operation
Internal 8 to 100V linear regulator
Input and output current sensing
Input current limit
Enable & PWM dimming
Ambient temperature rating up to 125°C
Meets AEC-Q100 requirements
General Description
The AT9933 is a variable frequency PWM controller IC,
designed to control an LED lamp driver using a low-noise
boost-buck (Ćuk) topology. The AT9933 uses patent-pending
hysteretic current-mode control to regulate both the input and
the output currents. This enables superior input surge immunity
without the necessity for complex loop compensation. Input
current control enables current limiting during startup, input
under-voltage and output overload conditions. The AT9933
provides a low-frequency PWM dimming input that can accept
an external control signal with a duty cycle of 0 - 100% and a
high dimming ratio.
The AT9933 based LED driver is ideal for automotive LED
lamps. The part is rated for up to 125°C ambient temperatures
and is AEC-Q100-Compliant.
Applications
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Automotive LED Lighting
Reference Documents
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AEC-Q100 Rev. F, 7/18/2003
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SAE J1752-3
Typical Application Circuit
D
2
(optional)
L
1
R
D
VDC
Q
1
R
CS1
R
CS2
R
S1
C
2
VIN
GATE
CS1
GND
VDD
PWMD
CS2
REF
C
3
R
S2
C
D
D
1
+
C
1
L
2
-
D
3
VO
R
REF1
R
REF2
AT9933
SUPERTEX [ Supertex, Inc ]
