A new specification from Zhaga adds to a scaled family of circular LED modules. The Book 11 modules operate with a separate driver, and are independently interchangeable.

The Zhaga Consortium has published Book 11, a new specification that describes circular LED modules with a maximum diameter of 35 mm that are suitable for spotlighting and related applications. A Book 11 module requires a separate LED driver.

Book 11 can be downloaded from the Zhaga website at www.zhagastandard.org/books/book11. The new specification has several important features, as follows.

Comparison between the new Zhaga Book 11 and previous Book 3 specs. (Photo Courtesy of Zhaga Consortium)

Scaled family of LED modules:

Book 11 forms part of a scaled family of LED modules with different sizes. Book 3, which is already published, describes 50-mm modules. Furthermore, each of these Books contains a set of categories defined by the size of the light-emitting surface (LES), ranging from 4.5 mm to 40 mm in diameter.

Separate Books for modules and drivers:

Book 11 is unique in being the first Zhaga Book to describe an LED module, rather than a complete LED light engine. Luminaire makers will use separate LED drivers with the Book 11 modules. Zhaga has also defined specifications for such drivers, and these will be included in the forthcoming Zhaga Book 13.

Driver-module interface:

Book 11 is also the first Zhaga Book to contain a reference to the LEDset specification for the electrical interface between a Book 11 LED module and a suitable driver. This so-called driver-module interface (DMI) is essential to enable the independent interchangeability of different drivers and modules. Zhaga has chosen to reference the LEDset specification developed by MD-SIG, rather than write a new specification.

Book 11 details

The circular LED modules in Book 11 have a maximum diameter of 35 mm and height of 3.5 mm. The modules are typically mounted into a luminaire using M3 screws. The mounting holes have a spacing of 25 mm and are defined so that the screws do not protrude above the top surface. Apart from these screw holes and other optional recessed features, the top surface of the Book 11 LED module is essentially flat and is intended to be used as the optics contact area (OCA).

Book 11 has three light-emitting surface (LES) categories, with maximum LES diameters of 6.3, 9.0 and 13.5 mm. The full list of LES categories for the different Zhaga LED spot modules can be viewed at www.zhagastandard.org/books/spot. Two LED modules with the same LES category should produce comparable light distributions when either one of them is used in the same luminaire.