HV9911_09 Datasheet, PDF (1/14 Pages) Supertex, Inc – Switch-Mode LED Driver IC with High Current Accuracy

HV9911
Switch-Mode LED Driver IC
with High Current Accuracy
Features
► Switch mode controller for single switch drivers
♦ Buck
♦ Boost
♦ Buck-boost
♦ SEPIC
► Works with high side current sensing
► Closed loop control of output current
► High PWM dimming ratio
► Internal 250V linear regulator (can be extended
using external Zener diodes)
► Internal 2% voltage reference (0°C < T_A < 85°C)
► Constant frequency or constant off-time operation
► Programmable slope compensation
► Enable & PWM dimming
► +0.2A/-0.4A GATE drive
► Output short circuit protection
► Output over voltage protection
► Synchronization capability
► Programmable MOSFET current limit
Applications
► RGB backlight applications
► Battery powered LED lamps
► Other DC/DC LED drivers
General Description
The HV9911 is a current mode control LED driver IC designed
to control single switch PWM converters (buck, boost, buck-
boost, or SEPIC), in a constant frequency or constant off-time
mode. The controller uses a peak current control scheme,
(with programmable slope compensation), and includes
an internal transconductance amplifier to control the output
current in closed loop, enabling high output current accuracy.
In the constant frequency mode, multiple HV9911s can be
synchronized to each other, or to an external clock, using
the SYNC pin. Programmable MOSFET current limit enables
current limiting during input under voltage and output overload
conditions. The IC also includes a 0.2A source and 0.4A sink
GATE driver for high power applications. An internal 9.0 -
250V linear regulator powers the IC, eliminating the need for
a separate power supply for the IC. HV9911 provides a TTL
compatible, 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 IC also provides a FAULT output
which, can be used to disconnect the LEDs in case of a fault
condition, using an external disconnect FET.
The HV9911 based LED driver is ideal for RGB backlight
applications with DC inputs. The HV9911 based LED lamp
drivers can achieve efficiency in excess of 90% for buck and
boost applications.
Typical Application Circuit - Boost
C_IN
C_DD
R_SLOPE
R_T
C_REF
L1
Q1
1 VIN
2 VDD
4 GND
GATE 3
CS 5
OVP 12
R_SC
SC
6 SC
FAULT 11
HV9911
7 RT
FDBK 16
10 REF
C_C
COMP 14
R_L2
9 _CLIM
R_L1
R_R1
15 IREF
R_R2
PWMD 13
SYNC 8
D1
R_OVP1
C_O
R_CS
R_OVP2
Q2
R_S
● 1235 Bordeaux Drive, Sunnyvale, CA 94089 ● Tel: [phone] ● www.supertex.com