HT7L4091_13 Datasheet, PDF (1/17 Pages) Holtek Semiconductor Inc – Universal Step-Down PWM Control For High Brightness LED Lighting Control

HT7L4091
Universal Step-Down PWM Control
For High Brightness LED Lighting Control
Features
• Input supply AC voltage range: 100V~240V
• Ultra low power-on start-up current < 30μA
• Integrated 25V Zener diode internally connected to
VIN pin
• 5V LDO output voltage with 6mA driving current
for external components
• Frequency jitter function for enhanced EMI
performance
• Efficiency > 85%
• Under Voltage Lockout function – UVLO
• Current mode operation with cycle-by-cycle
current limiting
• Over temperature protection function
• High-current FET drive output
• Linear and PWM dimming function
• Enhanced short circuit protection function
Applications
• AC/DC and DC/DC power control for high power
LED lighting
• RGB back lighting LED driver
• Flat panel displays back lighting
• General purpose constant current source
• Signage and decorative LED lighting
• Battery chargers
General Description
The HT7L4091 device provides a low-cost solution
for active current mode PWM controls of High
Intensity LED drive systems supplied by either AC or
DC line power lines. The device operates in constant
off-time mode which is suitable for buck LED drivers.
The low start-up and operating currents provides
flexible power requirements for high efficiency or low
cost applications. The switch frequency off-time can
be programmed using an external resistor. The peak
current mode control achieves good output current
regulation without requiring loop compensations for a
wide range of input voltages.
Included in the device is a PWM dimming input
which can accept an external control signal with a
duty ratio from 0 to 100%. The output current can
be programmed from 0 to 250mA by applying an
external control voltage on the linear dimming control
input.
The device includes a frequency jitter function which
helps to reduce EMI power supply emissions. Also
contained is an enhanced LED short circuit protection
feature to protect the internal circuitry from damage
should the LEDs be short circuited.
The device requires a minimum number of external
standard components and is available in an 8-pin SOP
package for small area PCB applications.
Ordering Information
Part Number
HT7L4091
HT7L4091-1
Function Description
Frequency jitter function enabled, VUVLO(H)=16V (typ.)
Frequency jitter function disabled, VUVLO(L)=8V (typ.)
Rev. 1.20
1
March 12, 2013