HV9931
HV9931 Unity Power Factor LED Lamp Driver
Features
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Constant output current
Large step-down ratio
Unity power factor
Low Input current harmonic distortion
Fixed frequency or fixed off-time operation
Internal 450V linear regulator
Input and output current sensing
Input current limit
Enable, PWM and phase dimming
General Description
The HV9931 is a fixed frequency PWM controller IC designed
to control an LED lamp driver using a single-stage PFC
buckboost-buck topology. It can achieve a unity power factor
and a very high step-down ratio that enables driving a single
high-brightness LED from the 85-264VAC input without a
need for a power transformer. This topology allows reducing
the filter capacitors and using non-electrolytic capacitors to
improve reliability. The HV9931 uses open-loop peak current
control to regulate both the input and the output current. This
control technique eliminates a need for loop compensation,
limits the input inrush current, and is inherently protected from
input under-voltage condition.
Capacitive isolation protects the LED Lamp from failure of the
switching MOSFET. HV9931 provides a low-frequency PWM
dimming input that can accept an external control signal with a
duty ratio of 0-100% and a frequency of up to a few kilohertz.
The PWM dimming capability enables HV9931 phase control
solutions that can work with standard wall dimmers.
Applications
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Offline LED lamps and fixtures
Street lamps
Traffic signals
Decorative lighting
Typical Application Circuit
D1
V
IN
D4
L1
C1
D2
L2
-
C
IN
~AC
~AC
R
S1
Q1
D3
R
S2
VO
+
R
ref2
R
CS1
R
ref1
R
T
VIN
GATE
CS1
GND
RT
PWMD
CS2
VDD
R
CS2
C2
HV9931
SUPERTEX [ Supertex, Inc ]
