HT7939A -- High Current and Performance White
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.
- 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: 0.1uA (typ.)
- Built-in OVP, OCP, OTP, UVLO protection
- EN pin dimming frequency up to 200kHz
- 1.2MHz fixed switching frequency
- SOT23-6 package