LED Driver Options
The Firelight Blaze fixture uses advanced high efficiency LED driver circuitry. This circuit allows the fixture
to operate from a wide range of DC input voltages, and drives two independent LED emitter channels with
individually optimized parameters.
The LED drive circuits are “switch mode” designs, which use high frequency resonant components to provide
drive current to the LED devices without the losses associated with linear control circuitry. The “charge
pump” frequency of 400 kilohertz is filtered and modulated to provide variable DC drive current to the LED
emitters.
The drive circuits can be configured to modulate the intensity of the LED emitters in any of 3 different ways.
The default control mode is the “Enhanced PWM” mode, which controls the intensity of the LED emitters by
adjusting both the LED current and the LED duty cycle to obtain excellent dimming performance, especially
at low intensity levels.
The other intensity control modes are “PWM Mode”, which modulates only the On / Off duty cycle of the
LED for intensity control, with the LED emitter always operated at a constant current, which assures a
constant color temperature. The frequency for all PWM duty cycle variation is 2.5 kilohertz, which is far
above the rate which can be perceived as a visual flicker, and is also well above the rate which may become
visible on most film or video camera systems. The PWM modulation frequency is synchronized for the two
LED drive channels, so that no inter-modulation effects are generated.
The remaining control mode is the “Analog Mode”, where the LED emitter is always active, but the LED
drive current is modulated to control the emitter intensity. In this mode, there is no PWM modulation of the
LED output, which will appear constant to the eye, and also on high speed film or video systems. All control
modes feature a positive LED shutoff at minimum intensity settings.
The default “Enhanced PWM” mode is suitable for almost all installations, but the other LED drive modes are
availa ble for specialized applications. Altering the LED drive mode will require disassembly of the fixture, so
users are advised to contact PPS in advance if LED drive modes other than the default are needed to best
suit your application.
LED Current Options
Each channel of the LED drive circuit is capable of driving LED emitters within the range of from .75 to 2.5
amperes. The maximum drive current for each channel is preset during manufacturing to match the
maximum current rating of the LED emitters installed in each fixture.
The maximum current is determined by the settings of a group of solder jumpers for each LED channel.
These jumper settings should not be altered, unless the LED emitters installed in the fixture have been
replaced with others with a different maximum current rating. Altering the LED current setting will require
disassembly of the fixture. Users are advised to contact PPS in advance if the application requires changing
the LED emitters, and making a corresponding adjustment to the maximum LED drive current levels.
CAUTION
Resetting the LED current jumpers to a higher current level may significantly reduce the LED
lifetime, and will void the warranty on the fixture.
