HV9985 Datasheet, PDF (1/16 Pages) Supertex, Inc – Three-Channel, Closed-Loop, Switch Mode LED Driver IC

Supertex inc.
HV9985
Three-Channel, Closed-Loop,
Switch Mode LED Driver IC
Features
►► Switch mode controller for single-switch
converters
►► Gate drivers optimized for driving Logic Level FETs
♦ 0.25A sourcing
♦ 0.5A sinking
►► Typical ±2% absolute and string-to-string current
accuracy (with ±1% sense resistors)
►► High PWM dimming ratio up to 5000:1
►► 10-40V input range
►► Constant frequency operation up to 1.0MHz
►► On-chip clock or external clock option
►► Programmable slope compensation
►► Linear and PWM dimming
►► Output short circuit protection
►► Output over voltage protection
►► Hiccup mode protection
Applications
►► RGB backlight applications
►► Boost, buck & SEPIC topologies
►► Multiple string white LED driver applications
General Description
The HV9985 is a three-channel peak current mode PWM
controller for driving single switch converters in a constant
output current mode. It can be used for driving either RGB LEDs
or multiple channels of white LEDs.
The HV9985 features a 40V linear regulator, which provides a
5.0V supply to power the IC. The switching frequencies of the
three converters in the IC are controlled either with an external
clock signal (the channels operate at a switching frequency
of 1/12th of the external clock frequency) or using the internal
oscillator. The three channels are positioned 120° out-of-phase
to reduce the input current ripple. Each converter is driven by a
peak current mode controller with output current feedback.
The three output currents can be individually dimmed using
either linear or PWM dimming. The IC also includes three
disconnect FET drivers which enable high PWM dimming ratios
and also helps to disconnect the input in case of an output short
circuit condition. The HV9985 includes hiccup mode protection
for both open LED and short circuit condition to prevent the IC
from shutting down in the case of intermittent faults.
Typical Application Circuit
D1b (Optional)
C_IN
C_IN1
L1
Q1a
D1a
R_OVP1a
C_O1
C_VDD
C_VDD1
C_SC1
R_SC1
R_CS1
R_OVP1b
VDD VDD1 GT1
CS1
GND1 OVP1
VIN
FLT1
Q1b
GND
HV9985
FDBK1
EN
(One Channel Shown)
COMP1
RT
R_T
PWMD1 CLK
SKIP REF1
C_C1
R_S
C_SKIP
C _{R REF1 REF1}
REF
Doc.# DSFP-HV9985
C051513
Supertex inc.
www.supertex.com