Steve Jobs


“Scattering Cold Illuminating Light Source (SCILS)”, 1999.
“LED Illumination Control System (ICS)”, 2001.
“Illumination Control System for Light Emitters”, 2003.
“Improvements to Lighting Control Systems”, 2007.
“Collimated Illumination System using an Extended Apparent Source Size" 2008.
"Power-Configurable, High Reliability Hybrid Control System" 2011.
"Power control system for an illumination system", 2012

“Improvements in or Relating to Lighting Control Systems”, 2007.

UK Patent No: 2 443 091; USA Application No: 12/738 750;

European Application No: 08750475.9

Filed: 19th October, 2007

The patent also known as the variable voltage patent describes various embodiments of improvements to light power control systems to increase efficiency and lifetime of LED systems. Embodiments include examples of driving AC or DC LEDs, the use of single or multiple transformers, power feedback, lighting fixtures that are detachable from the power systems as well as colour mixing of light sources.

click image to enlarge

Patent areas covered:

  •  AC or DC LED driving
  • Colour mixing
  • PWM, DC, PAM, PFM and more
  • Multiple transformers 
  • Power Feedback
  • Variable Voltage / Power systems
  • Detachable Light Fixtures
  • Power Factor Correction
  • Higher PSU power is achieved without
    forced air cooling
  • Improved overall AC/DC PSU efficiency ~85%
  • Independent Channel Characteristics –
    any number or type of LED configuration
    is possible

Claim 1: A system for controlling solid state lighting comprising:

  • a source to supply any one of a range of AC or DC voltages;

  • a means for controlling the power factor to the system;

  • one or more power transformers each connecting to

  • + one or more LED strings;

  • a switching means for each string
    for limiting the currents that can pass through the LED string;

  • a sensor monitoring the voltage applied across the switching means;

  • feedback means for controlling the power transformer;

  • the feedback means varying the voltage supply in response to a monitored voltage across the switching means;

  • the feedback means being arranged to cause the power transformers to increase or decrease the voltage according to a predetermined upper and lower voltage level to a particular LED string enabling a means for constant current operation.

click image to enlarge

Figure from the UK Patent which
shows one embodiment of the
power control system (right)

The patent teaches methods of changing the voltage supply in response to the voltage drop across the switching device allowing one to minimise any excess voltage, reducing power converted to heat, thus improving the efficiency of the lighting control system. In this way, the circuit may be operable without a heat sink. This reduces the cost of the system and allows the system to work over an extended temperature range, as there is less self-heating.