3 Sep 2015 / Zhaga /

Zhaga publishes Book 11 specification for small LED

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

Book 11 can now be downloaded from the Zhaga website. The new specification has several important features, as follows.

  • 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, while the forthcoming Book 10 describes 75-mm modules. Furthermore, each of these Books contains a set of categories defined by the diameter of the light-emitting surface (LES), ranging from 4.5 mm to 40 mm – see below for more details.

  • Separate Books for modules and drivers:

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

More information: See "Zhaga writes Book 13 specification for LED drivers"

  • Driver-module interface:

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

More information: See "MD-SIG unveils specification for module-driver electrical interface"

Book 11 details

The circular LED modules in Book 11 have a diameter of 35 mm and a height of 3.5 mm. Three categories of light-emitting surface (LES) size are defined, with diameters ranging from 4.5 mm to 13.5 mm – see Table below. Two LED modules with the same LES category should produce comparable photometric properties when either one of them is used in the same luminaire. 

A Book 11 LED module is typically mounted into a luminaire using M3 screws, and the module has screw holes such that the screws that 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).

Light-emitting surface (LES) categories

LES category

Minimum LES

diameter (mm)

Maximum LES

diameter (mm)

Book 11 Book 3 Book 10
LES 6.3 >4.5 6.3 X    
LES 9 > 6.3 9.0 X X  
LES 13.5 > 9.0 13.5 X X  
LES 19 > 13.5 19.0   X  
LES 23 > 19 23   X X
LES 30 >23 30     X
LES 40 >30 40     X


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