POWERdrive 50W DESIGN GUIDE
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July 30, 2020
Page 11/19
Short protection
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All LED outputs are turned off whenever the LED driver detects a short circuit on any one of
the LED outputs. The LED driver will automatically attempt a restart every 400ms after a short-circuit is detected.
Overload protection
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The driver monitors the cumulative load across all LED outputs. Whenever this cumulative
load exceeds the maximum output power rating of the LED driver, the output current on all LED outputs is
gracefully scaled down until the cumulative load drops below the maximum output power rating of the LED
driver.
Reverse polarity
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The LED driver does not yield any current if the polarity of the load on the LED output is
reversed. This situation will not damage the LED driver but may damage the LED load due to the reverse voltage
across the LEDs.
These protection mechanisms typically kick in if one or more of these limits are violated:
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The current of any LED output exceeds 1400mA
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The cumulative current for all LED outputs exceeds 3400mA
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The LED load on any LED output exceeds 55V
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The total output power of the driver exceeds 50W
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The internal LED driver temperature exceeds a factory preset limit
The first limit is pro-actively enforced during programming of a POWERdrive LED driver in FluxTool, i.e. the nominal
current for any one LED output cannot be programmed above 1400mA. The other limits cannot be enforced when
programming a POWERdrive LED driver since these are dependent on factors that are beyond eldoLED
’
s control, including:
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the operating conditions in the final application
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the LED loads that are connected
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the number of LED outputs that are on
For example, the nominal current for each LED output can be programmed to, say, 1000mA, resulting in a cumulative
programmed current of 4000mA. This situation is acceptable if the DMX controller ensures that at most 3 LED outputs are
at 100% at any one time, resulting in an effective cumulative current of only 3000mA. Now, l
et’s further assume that the
maximum LED forward voltage on each LED output is 25V. The total output power now becomes the critical limit, i.e. at
most 2 LED outputs can be on at 100% at any one time.
It is the responsibility of the luminaire design engineer to ensure none of the limits above are violated in the targeted
application, including worst-case operating conditions such as cold start-up.
5. Mechanical installation
Driver Lifetime
eldoLED drivers are designed to operate reliably if the case temperature (Tc max) of the driver does not exceed the
maximum allowable case temperature as specified in the product datasheet. The driver case temperature to meet a
lifetime of 50k hours is also specified in the product datasheet. The fixture design must guarantee that the Tc point stays
below its maximum value under all operating conditions of the luminaire.
