IEC 63128:2019/AMD1:2024

IEC 63128 ®
Edition 1.0 2024-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
AMENDMENT 1
AMENDEMENT 1
Lighting control interface for dimming – Analogue voltage dimming interface for
electronic current sourcing controlgear

Interface de commande d'éclairage pour variation d'intensité – Interface de
variation de tension analogique pour appareillage d'alimentation électronique

IEC 63128:2019-05/AMD1:2024-07(en-fr)

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IEC 63128 ®
Edition 1.0 2024-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
AMENDMENT 1
AMENDEMENT 1
Lighting control interface for dimming – Analogue voltage dimming interface for

electronic current sourcing controlgear

Interface de commande d'éclairage pour variation d'intensité – Interface de

variation de tension analogique pour appareillage d'alimentation électronique

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.140.99  ISBN 978-2-8322-9297-6

– 2 – IEC 63128:2019/AMD1:2024
© IEC 2024
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LIGHTING CONTROL INTERFACE FOR DIMMING –
ANALOGUE VOLTAGE DIMMING INTERFACE FOR
ELECTRONIC CURRENT SOURCING CONTROLGEAR

AMENDMENT 1
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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Amendment 1 to IEC 63128:2019 has been prepared by IEC technical committee 34: Lighting.
The text of this Amendment is based on the following documents:
Draft Report on voting
34/1053/CDV 34/1137A/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Amendment is English.

© IEC 2024
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications/.
The committee has decided that the contents of this document will remain unchanged until the
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specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
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___________
3 Terms and definitions
Insert, between the existing entries 3.5 and 3.6, the following new entry 3.8:
3.8
correlated colour temperature factor
CCTF
ratio of the dimmed CCT to the full power CCT
Note 1 to entry: This ratio is used in the calculation of warm dimming responses for applicable LED systems.
Note 2 to entry: CCT (correlated colour temperature) is defined in IEV 845-23-068.
Add, at the end of Clause 3, the following new entry 3.9:
3.9
warm dimming
capability of controlgear to decrease the colour temperature of its LED light sources as the
power, and therefore the luminous flux output of the light sources is decreased
5 Marking
Replace the last sentence below Figure 1 with the following:
Markings should be readable with normal vision.

– 4 – IEC 63128:2019/AMD1:2024
© IEC 2024
6.5 Switch-on
Add, at the end of 6.5, the following new Clause 7:
7 Simulation of incandescent dimming (optional)
7.1 General
Warm dimming is an optional feature implemented in some lighting controlgear to imitate the
behaviour of incandescent filament sources as the power supplied to them is decreased. If
warm dimming is implemented, 7.2 shall apply.
For lighting systems that implement warm dimming and can utilize a variety of luminaires or
light sources, uniform warm dimming response can be important for colour consistency
throughout the lighting system.
7.2 Response to light source dimming
For an LED dim-to-warm system, the resultant output CCT for a given output power P, is
determined as follows:
P = P/P
r max
0,37
CCTF = P
r
CCT = CCTF × CCT
max
where
P is the power delivered to the LEDs;
P is the maximum undimmed power delivered to the LEDs;
max
P is the relative power;
r
CCTF is the CCT factor;
CCT is the maximum CCT;
max
CCT is the resultant output CCT at the given output power P.
Annex A provides examples of a relationship between the CCTF and an analogue 0 V to 10 V
control voltage.
When implementing warm dimming, it is recommended that the minimum CCT is no less than
1 800 K.
© IEC 2024
7.3 Dim-to-warm marking
Electronic light source controlgear utilizing the dim-to-warm functionality in accordance with
this document shall be clearly marked with the following marking (see Figure 4):

Figure 4 – Marking of dim-to-warm electronic light source controlgear
Markings should be readable with normal vision.
Add, at the end of Clause 7, the following new Annex A:

– 6 – IEC 63128:2019/AMD1:2024
© IEC 2024
Annex A
(informative)
Warm dim control for analogue dimming having controlgear
with a linear output power to control voltage response
A.1 General
Typically, dimming an LED simply lowers its luminous flux output while maintaining its rated
colour temperature. Legacy heated filament lamps (incandescent) respond to dimming by a
significant shift to warmer colour temperatures at lower power. This dim-to-warm characteristic
is often a desirable response. Implementation of a dim-to-warm feature in an LED luminaire
allows this response to be available along with the other positive features of LED equipment.
Typical warm dim systems utilize a dimmable LED driver with at least two output channels.
Each channel controls an LED of a different colour temperature (CCT). The overall CCT of the
system is controlled by independently varying the power delivered to each of the LEDs and
mixing the output of all the LED sources to achieve a composite, uniform CCT. As an example,
a basic block diagram of a two-channel system is shown in Figure A.1.

Figure A.1 – Typical warm dimming LED system utilizing two LED sources
A.2 Correlation to 0 V to 10 V control
In the warm dim control standard as described in Clause 7, the CCT during dimming is based
on the relative power supplied to the LED source. Determining the CCT factor as a function of
the 0 V to 10 V control voltage, V , of an analogue dimmer is more complex since the control
c
voltage to power function is not completely defined for the controlgear. The minimum dimmed
power depends on the design of the controlgear and should be taken into account in the
calculation of the CCTF.
For controlgear that meets the following criteria, the CCTF for a given control voltage V can
c
be calculated using Formula (A.1) where:
• the total LED power, P, is the sum of all power delivered to the LEDs involved in the dim-to-
warm function;
• the minimum total LED power, P , occurs when V = V ;
min c min
IEC 63128:2019/AMD1:
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