General Principles for 110/220V LED Lighting Designs

ZLED7001 is a LED controller IC designed for implementing DC-to-DC converters with only a few external components. Operating as a buck converter, it is especially suitable for highly efficient driving of LED loads. When using an external switching transistor with the ZLED7001, supply voltage and LED power can be selected in a very wide range. However, some basic considerations must be taken into account when driving LEDs from a line voltage as high as 110 VAC or 230 VAC. 

The following white paper reviews selection of capacitors, design of line-filters, efficiency trade-offs, power factor correction and limitations of switching transients.

General Principles for 40V LED Lighting Designs

The ZLED7000 and ZLED7020 are LED controller ICs designed for achieving DC-DC converters, including buck converters, with very few external components, especially suitable for driving LED loads with high efficiency from a DC voltage up to 40 V or a rectified AC voltage up to 28 V (if sinusoidal). The main difference between the two devices is the on-resistance and therefore the current capability of their internal power switches. The ZLED7000 is suitable for LED currents up to 700 mA, the ZLED7020 for currents up to 1.2 A. Both devices are available in a small SOT89-5 package with exposed die pad, enabling low thermal resistance from junction to ambient temperature.

The following application note reviews the theory of operation, selection of components (including capacitors and inductors), dimming and efficiency trade-offs. It provides component selection information on 24 different system designs covering standard LED currents of 150mA, 400mA, 700mA and 1A.