Microchip HV9805 | Demoboard AN2080

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 120VAC and about 50W at 230VAC.

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 overheadvoltage, 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 VDD 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 VDD 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.

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 VDD Supply: No Auxiliary Winding Required
• Boost Converter Cascode Switch:
• Internal Switch rated at 700 mA peak
• Supports up to 25W at 120VAC
• Supports up to 50W at 230VAC
• Compatibility with SEPIC Topology for Low Output Voltage Applications

Remarks:

• From HV9805120VAC Off-Line LED DriverEvaluation Board User’s Guide, Inductor value L1=L2=1.5mH is used in input side, L3=1000uH is used in output side.
• From HV9805 230VAC Off-Line LED Driver Evaluation Board User’s Guide, Inductors L=L2=6.8mH is at the input signal, L3=3.3mH is considered at the output signal
• From this link-

http://ww1.microchip.com/downloads/en/DeviceDoc/50002362A.pdf

L52=5.6mH,L51=10mH,L50=1.5mH,CMC1=4.7mH are used

Typical applications

• LED Lamps
• LED Lighting Fixtures

More information

• Datasheet
• IC product information