HV9805 Datasheet, PDF (1/34 Pages) Microchip Technology – Off-Line LED Driver with True DC Output Current

HV9805
Off-Line LED Driver with True DC Output Current
Features
• Provides True DC Light and protects load from
line voltage transients
• Driver topology includes:
- Boundary Conduction Mode (BCM) Boost
Converter with Power Factor Correction
a) High Power Factor (98% typical)
b) High Efficiency (90% typical)
- Linear Post-Regulator with Low Overhead
Voltage
a) Zero LED Current/Brightness Ripple
b) Overvoltage Protection for LEDs
c) High Efficiency
d) ±4% Reference Over Temperature
• Simple V_DD Supply:
- No Auxiliary Winding Required
• Boost Converter Cascode Switch:
- Internal Switch rated at 700 mA peak
- Supports up to 25W at 120V_AC
- Supports up to 50W at 230V_AC
• Compatibility with SEPIC Topology for
Low Output Voltage Applications
Applications
• LED Lamps
• LED Lighting Fixtures
Network Topology Diagram
General Description
The HV9805 driver integrated circuit (IC) is targeted at
general LED lighting products, such as LED lamps and
LED lighting fixtures with a maximum power rating of
about 25W at 120V_AC and about 50W at 230V_AC.
A two-stage topology provides true constant current
drive for the LED load while drawing mains power with
high power factor. The first stage, a boundary
conduction mode boost converter, transfers power
from the AC line to a second stage with high power
factor and high efficiency. The second stage, a linear
regulator arranged for operation with low overhead
voltage, transfers power from the first stage to the LED
load with true constant current and protects the LED
load from overvoltage that may pass from mains to the
output of the first stage.
The IC is particularly geared to drive a high voltage
LED load. An LED load arranged as a high-voltage load
is capable of offering cost advantages in terms of heat
management and optics.
The boost converter employs a cascode switch for
high-speed switching and convenient generation of the
V_DD supply. The control device of the cascode switch is
an integral part of the HV9805 and is rated at 700 mA
peak. Current for powering the V_DD supply is derived
by way of an internal connection to the cascode switch.
Applications with low output voltage can be
accommodated using the SEPIC topology.
AC
 2015 Microchip Technology Inc.
DS20005374A-page 1