Key words:
LED driver, LNK405EG, PAR38, TRIAC, dimming
This article describes the high power factor (PF) TRIAC dimming LED driver of PowerInt. The drive is designed to drive the rated LED string voltage of 30 V (at a current of 0.5a) whose input voltage ranges from 180 Vac to 265VAC. The LED driver uses the LNK405EG of the LinkSwitch-pH series IC.
The LinkSwitch-PH IC achieves low cost, low-element LED drivers, which meet both power factor and harmonic restrictions, and strengthen the end user experience. It has a wide range of dimming ranges, no flashing operation (even with cost characteristics of the AC line TRIAC dimmer), fast and clean open characteristics.
It uses isolation-type anti-intensive structure to operate in continuous conduction mode. It is completely adjusted through the primary side induction output current, thereby eliminating the need for secondary feedback elements. Since this is performed inside the IC, there is no need for external current sensing in one side, thereby further reducing the number of components and reduces loss. The internal controller can adjust the MOSFET duty cycle to keep the sinusoidal input current, and maintain high power factor and low harmonic current.
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Figure 1 15W dimming LED driver profile
The LinkSwitch-PH IC also provides a variety of advanced protection features, including automatic restarts in the case of control loop opening and output short circuit. The line overflows extend the power of the line failure and surge, and the output overvoltage can protect the power of the power supply in the case of load disconnect, and accurate delay heat shutdown can ensure a safe PCB average temperature under various conditions. Regardless of which LED source, the drive can determine the performance attributes experienced by the end user. This design emphasizes the compatibility with various dimmers, which can achieve as wide as possible at a voltage of 230VAC.
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Figure 2 15W dimming LED driver motherboard circuit diagram
Main performance
• Design focuses on compatibility with standard TRIAC dimmers
• Model compatible with rated power is 1000W (VS. 600W)
• No output flashes
• Will not produce a sound from the low phase angle
• Dimming range of up to 1000: 1 - limit on only connected dimuses
• Monoled start - no output flash
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Figure 3 Motherboard element layout map (top layer)
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Figure 4 Motherboard element layout map (under layer)
• High energy efficiency
• Comprehensive protection and reliability characteristics of more than 84% efficiency over a voltage of 230VAC
• Output open / output short circuit protection and automatic recovery
• When a line failure occurs, the line input overvoltage is turned off to extend the voltage range.
• Automatic recovery heat shutdown feature with long delay characteristics protects components and printed circuit boards
• Comply with IEC61000-4-5 ring wave, IEC61000-3-2 Class Class IEC61000-3-2 Class Class IEC61000-3-2 Class C and EMI requirements
For details, please see:
PowerInt LNK405EG 15W PAR38 TRIAC dimming LED driver (DER-281)
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