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9/20/2004

Supertex, Inc. 1235 Bordeaux Drive, Sunnyvale, CA 94089 TEL: (408) 222-8888 FAX: (408) 222-4895 www.supertex.com

HV9906

(Simple Off-Line/PFC & >9V DC/DC Switcher)

Features

Drive one or hundreds of LEDs including White LEDs

Programmable Current Source (mA to A)

Programmable Voltage Source (Steps Up or Down)

Integrator Lock Loop Technology (IL

o

Built in Soft Start

o

Allows Discontinuous Feedback

o

Eliminates Compensation Components

o

Eliminates Output Averaging Filters

o

Inherent Dither to Reduce EMI

Eliminates High Voltage Input Electrolytic Capacitor

Smallest and Most Reliable Off-Line Solution

Isolated or Non-Isolated Applications

Can be Operated Directly from Rectified AC Mains

10V to 400V Input Range Internal Regulator

<1.5mA Operating Supply Current

Programmable Feed Forward Regulation

Programmable Feedback Sense Threshold (mV to V)

Integrating Differential Sense Feedback

Applications

LED driver

Power Factor Correction

Constant Current or Voltage Source

Battery Charger / PWM Housekeeping Supplies

Traffic Lights / Street Lights

Back Lighting of Flat Panel Displays

Advertising Signs

General Description

The Supertex HV9906 allows the development of the smallest

possible, most reliable, offline and wide DC/DC conversion range

converters for driving LEDs and other applications. The HV9906

combines internally all the components required to operate directly

from the rectified AC line with a feedback mechanism that

eliminates compensation components.

The HV9906 is capable of driving cascaded converters (multi-

converters), which have been shown to provide the best

performance to component count trade off for wide conversion

range applications like off-line converters with or without power

factor correction (PFC). Bulky and unreliable electrolytic capacitors

can be replaced with lower value non-electrolytic ones or

eliminated completely when using HV9906.

Proper choice of external components will allow the programming

of currents from <1mA to several amps.

The HV9906 utilizes a programmable inversely proportional fast

feed forward algorithm to calculate output on time and a novel

Integrating Lock Loop (IL

differential sensing.

The sensed feedback may be positive or

negative with respect to ground and the signal may be

discontinuous. This algorithm when used with certain multi-

converters such as the flyback-buck, with a fixed load, results in

near constant frequency with only a small dither which helps meet

FCC requirements.

Typical Application Circuit