Linear Dimming(PT6907)

The PT6907 is a buck LED driver which has linear dimming function with normal switch ON/OFF. While turning-on the switch first time, the LED current will increase from the minimum value to the maximum current during about 7 seconds. The PT6907 builds-in exponential algorithm and the LED’s brightness changes smoothly and linearly. During the dimming processing, you can turn-off the switch when the LED’s brightness reaches the level you want. The PT6907 can remember and hold the status for a certain time which is programmable after turned-off. You should turn-on the switch again within this holding time. Then the output stays at remembered level. If you don’t turn-off the switch during dimming processing, the output will increase to the maximum value and hold the status finally.

The PT6907 also integrates 10bit DAC. It is flexible for synchronous application. You can use only one switch to control the group LED lamps. They change synchronously using the power line AC clock. The PT6907 operates in open loop current mode control, and the controller achieves good output current regulation without the need for any loop compensation. Also, the PT6907 operates in constant frequency mode. The frequency is set as 50KHz.

FEATURES
• 8V to 12V Input Voltage Range
• Low Start-up Current
• Constant Frequency Operation, 50kHz typical
• Open Loop Peak Current Controller
• Linear Dimming with Normal Switch On/Off
• Programmable Holding Time
• Dimming with Exponential Algorithm, More Suitable for Human Eyes.
• 10bit DAC Integrated for Synchronous Application, More Flexible for Group Control
• Normal Switch Compatible
• SOP8 Package