HV9931_07 Datasheet, PDF (1/8 Pages) Supertex, Inc – HV9931 Unity Power Factor LED Lamp Driver

HV9931
HV9931 Unity Power Factor LED Lamp Driver
Features
► 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
Applications
► Offline LED lamps and fixtures
► Street lamps
► Traffic signals
► Decorative lighting
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.
Typical Application Circuit
V_IN
D4
~AC ~AC
C_IN
R_S1
R_ref1
R_CS1
D1
L1
C1
D2
L2
-
D3
Q1
VO
R_S2
+
R_CS2
R_T
VIN
RT
GATE PWMD
R_ref2
CS1
CS2
GND
VDD
C2
HV9931