HT7939A
HT7939A is High Current and Performance White LED Driver manufactured by Holtek Semiconductor.
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: 0.1m A (typ.)
- Built-in OVP, OCP, OTP, UVLO protection
- EN pin dimming frequency up to 200k Hz
- 1.2MHz fixed switching frequency
- 6-pin SOT23 package
Applications
- Display backlighting
- - Automatic
- - DVD player
- - Digital photo frame
- - Handheld puter
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 200k Hz, 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 bee 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-1 HT7939A-2
Package SOT23-6
Note: Both lead free and green pound devices are available.
Marking
39A-1 (OVP=17.6V) 39A-2 (OVP=32.0V)
Rev. 1.30
August 04, 2018
Block Diagram
O VP P ro te c t
O VP 1 7 .6 V (3 9 A -1 ) 3 2 .0 V (3 9 A -2 )
R am p
1 .2 M H z O SC
O...
