HT7939A_16 Datasheet, PDF (1/12 Pages) Holtek Semiconductor Inc – High Current and Performance White LED Driver

HT7939A
High Current and
Performance White LED Driver
Feature
• Input voltage range: 2.6V~5.5V
• High efficiency - up to 90%
• Integrated N-ch MOSFET
• Can drive up to 39 WLEDs from a 5V input
• Low standby current: 0.1mA (typ.)
• Built-in OVP, OCP, OTP, UVLO protection
• EN pin dimming frequency up to 200kHz
• 1.2MHz fixed switching frequency
• SOT23-6 package
Applications
• Display backlighting
–– Automatic
–– DVD player
–– Digital photo frame
–– Handheld computer
General Description
The HT7939A is a high efficiency boost converter
for driving multiple White LEDs using current mode
operation. The device is designed to drive up to 39
White LEDs from a 5V power supply. The White
LED current is setup using an external current setting
resistor, which has a low feedback voltage of 0.2V to
minimise resistor power losses and thus improving
efficiency.
The HT7939A has a dimming frequency of up to
200kHz, which has excellent linear performance
over this dimming frequency range. The over voltage
function prevents device damage by turning off the
converter should the LED load become open circuit.
The device also includes over current protection, over
temperature protection and under voltage protection
preventing damage to the device should the output be
overloaded.
Selection Guide
Part No.
HT7939A
Package
SOT23-6
Note: Both lead free and green compound devices are available.
Marking
39A-1 (OVP=17.6V)
39A-2 (OVP=32.0V)
Rev. 1.20
1
November 04, 2013