PT6905_10 PTC | Alldatasheet
Document overview
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Technical content
3-Stage Dimming LED Driver Tel: 886-66296288‧Fax: 886-29174598‧ http://www.princeton.com.tw‧2F, 233-1, Baociao Road, Sindian, Taipei 23145, Taiwan
DESCRIPTION
The PT6905 is a continuous mode inductive step-down converter with three-stage dimming, designed for driving single or multiple series white LEDs efficiently from a voltage source higher than t he output LED voltage. The IC operates from an input supply between 6V and 36V and provides three-stage dimming with output current of up to 1.2Amp. The PT6905 includes the internal switch and a high-side output current sensing circuit, which uses an external resister to set the average output current. The PT6905 has a three-stage dimming function. That is to say the output current will be adjusted to 100% when the first time power on corresponding to stage-one, 30% when the second time power on corresponding to stage-two and 10% when the third time power on corresponding to stage-three. The cycle will restart to stage-one again when the fourth time power on. So this cycle will go on if the power off time is no less than six seconds according to the external capacitor Cs of 10 μF. And the power could be saved if less light needed.
FEATURES
- High Efficiency (up to 95%)
- Maximum 1.2A Output Current
- Wide Input Voltage: 6V ~ 36V
- Three-Stage Dimming
- Typical 5% Output Current Accuracy
- Thermal Shutdown 150 ℃ Typical
- SOT-89-5L Package
APPLICATIONS
- DC/DC LED Driver
- Low Voltage Industrial LED Lighting
- Low Voltage Halogen Replacement LEDs
- Decorative LED Lighting
- LED Table Lighting BLOCK DIAGRAM
PRE1.1 2 May 2010 TYPICAL APPLICATION
PRE1.1 3 May 2010 ORDER INFORMATION Valid Part Number Package Type Top Code PT6905 SOT-89-5L PT6905 PIN CONFIGURATION PIN DESCRIPTION Pin Name Description Pin No. LX Drain of The Internal NMOS Switch 1 GND Signal Ground 2 VRGS Output of Internal Regulator Voltage of Logic 3 ISNS Inductance Current Sense Pin 4 VIN Input Supply Pin. Must be locally bypassed. 5 Exposed PAD Power Ground
PRE1.1 4 May 2010 IMPORTANT NOTICE Princeton Technology Corporation (PTC ) reserves the right to make co rrections, modifications, enhancements, improvements, and other changes to its products and to discontinue any product without notice at any time. PTC cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a PTC product. No circuit patent licenses are implied. Princeton Technology Corp. 2F, 233-1, Baociao Road, Sindian, Taipei 23145, Taiwan Tel: 886-2-66296288 Fax: 886-2-29174598 http://www.princeton.com.tw