PT4105 Datasheet Text
Step-Down Power LED Driver
GENERAL DESCRIPTION
Features
The PT4105 is a step-down DC/DC converter designed to operate as a high current LED driver. The PT4105 uses a voltage mode, fixed frequency architecture that guarantees stable operation over wide range of supply voltages and load conditions. The PT4105 senses the output current by measuring the voltage across an external resistor in series with the high current LED. This voltage is then fed back to the PT4105 to control the PWM signal that drives the switching device to achieve accurate current regulation. The low 200mV feedback voltage greatly reduces the power dissipation on the external current sensing resistor and therefore improves the overall efficiency. The value of the external resistor can be adjusted to program the LED current. Using the PT4105 with a few external ponents, a buck power LED driver with efficiency of up to 90% can be easily constructed. The PT4105 has the built-in protection functions including current limiting, UVLO and thermal shutdown, which prevent the device from damage caused by potential fault conditions. The PT4105 is available in SOP8 packages. z Wide Range Of Input Voltage: 4.5V~12V z Low Feedback Voltage: 200mV z Oscillation Frequency: 500kHz z Standby Current: Typical 0.1µA z High Efficiency: Typical 88% z Low Temp. Coefficient of Feedback Voltage: z Typical ±100ppm/℃ z Built-in Soft-start and UVLO z Thermal Shutdown z Package: SOP-8
APPLICATIONS z Architecture Detail lighting z Constant Current Source z Hand-held lighting
ORDERING INFORMATION
PACKAGE SOP8
TEMPERATURE -40℃ to 85℃
PART NUMBER PT4105BSOH
TRANSPORT MEDIA Tape and Reel
TYPICAL APPLICATIONS
KEY PERFORMANCE CHART
Efficiency (%)
Efficiency vs. Output...