June 17, 2010
Compliance with Harmonics Standards without Using PFC Circuit
New LED Driver ICs - LC5500 Series
Integrated MOSFET and Startup Circuit Requires Fewer Components
Sanken Electric Co., Ltd. is announcing the new LC5500 series of LED driver ICs (five types in different power output levels and packages) that designers may use to develop harmonics standards compliant designs without any PFC circuit. Samples are now available, priced at ¥300 to ¥500 each. Sanken plans to begin their volume production and shipments in August 2010, starting at the rate of 300,000 units per month and ramping up to 3 million units per month by 2011.
Sanken has been developing and marketing LED driver ICs for LED fixtures that replace incandescent light bulbs. To meet requirements for smaller size and lower cost, Sanken has focused on supplying inexpensive, non-isolated types to lower component counts.
On the other hand, safer isolated types are specified for higher-power LED lighting applications, such as downlights, fluorescent lamps, other general lighting, and compact streetlights. Additionally, these higher power applications also require high efficiency and compliance with harmonics standards.
PFC circuits are typically added to achieve compliance with harmonics standards. But, it has been difficult to reach high efficiency because power was converted twice: first at the PFC circuit and then at the converter circuit.
LC5500 series offers isolated types that incorporate Sanken’s proprietary internal circuit to improve the power factor while achieving a high efficiency of 98% at 220VAC. They do not use any PFC circuit: power is converted only once (single-converter method), thus enabling compliance with harmonics standards (IEC61000-3-2 Class C). In addition, its quasi-resonant operation achieves both low noise and high efficiency (89% typical).
The power device (MOSFET) is mounted externally for most of the driver ICs in the market today. The LC5500 series incorporates a low on-resistance MOSFET as well as a startup circuit, which was also added externally for some ICs. This leads to a further reduction in component count and design resources.
Triac dimmers are often used to dim incandescent lighting. With addition of an external circuit, the LC5500 series allow dimming of LED lighting using any pre-installed triac dimmers.
Non-isolated LC5500 types in the low to mid-power levels (up to 20W) are also available, as some countries’ regulations may require non-isolated type.
(1) Harmonics standards compliance
The harmonics standards compliance for power supply for lighting (IEC61000-3-2 Class C) is achieved without any PFC circuit.(2) Built-in control IC and high voltage MOSFET
- Power MOSFET (650V) is incorporated. Universal input voltage (88 to 288V).(3) Non-isolated types for low to mid-power levels
Non-isolated types are added to the lineup to meet regulatory requirements for the non-isolated type in various countries.(4) Two types of package are added to the lineup according to the load power
- DIP8: resin dimension 9.4×6.5×3.4mm (up to 20W)(5) High efficiency
- TO220F-7: resin dimension 10×15×4.2mm (up to 60W)
Quasi-resonant operation achieves low noise and high efficiency (89% typical).(6) Various protection functions
- Overcurrent protection (Leading Edge Blanking function is incorporated for malfunctions)(7) Available for various applications with external circuits
- Overload protection
- Overvoltage protection
- Thermal protection
- Triac dimming
- Step down chopper type
- Step up chopper type
|LED lighting (up to 60W class), general lighting (LED lamps, downlights), streetlights|