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GB 24850-2020: Minimum allowable values of energy efficiency and energy efficiency grades for flat panel televisions and set-top boxes
GB 24850-2020
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 27.010
F 01
Replacing GB 24850-2013, GB 25957-2010
Minimum allowable values of energy efficiency and
energy efficiency grades for flat panel televisions and
set-top boxes
ISSUED ON: JULY 23, 2020
IMPLEMENTED ON: AUGUST 01, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 5 
2 Normative references ... 5 
3 Terms and definitions ... 6 
4 Energy efficiency grades ... 8 
5 Minimum allowable values of energy efficiency ... 8 
6 Calculation method for energy efficiency ... 9 
7 Test methods for energy efficiency ... 11 
Annex A (normative) Test methods for energy efficiency for flat panel televisions
... 12 
Annex B (normative) Test methods for passive standby power for flat panel
televisions ... 19 
Annex C (normative) Test methods for power for set-top boxes ... 21 
Annex D (informative) Adjustment process of image contrast and brightness of
flat panel televisions ... 30 
Minimum allowable values of energy efficiency and
energy efficiency grades for flat panel televisions and
set-top boxes
1 Scope
This Standard specifies energy efficiency grades, minimum allowable values of
energy efficiency, energy efficiency calculation and test methods for flat panel
televisions and general-purpose set-top boxes (also known as "digital TV
receiver").
This Standard is applicable to LCD TV and OLED TV that work normally under
AC220V, 50Hz power supply conditions; of which the main functions include
ground, cable, satellite or other analog and digital signal reception,
demodulation and display (hereafter collectively referred to as "flat panel TV").
It is also applicable to liquid crystal and OLED display device of which the main
function is a TV, without a tuner, but it is circulated as a TV product. This
Standard applies to set-top boxes that work normally under AC220V, 50Hz
power supply conditions, including cable set-top boxes, ground set-top boxes,
satellite set-top boxes and network set-top boxes.
This Standard is not applicable to live broadcast satellite set-top boxes.
2 Normative references
The following referenced documents are indispensable for the application of
this document. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any
amendments) applies.
GB 3174, Characteristics of PAL-D television broadcasting system
GB/T 8170, Rules of rounding off for numerical values and expression and
judgement of limiting values
GB/T 14857, Specifications of encoding parameters of digital television for
studio
GB/T 17309.1, Methods of measurement on receivers for television
broadcast transmissions - Part 1: General considerations - Electrical
3.2 passive standby mode
the flat panel TV is connected to power supply and produces neither sound nor
image, but it can be switched to on mode by remote control or other external
signals
low power state that the set-top box is connected to power supply and does not
provide the main function
NOTE: The set-top box can enter this mode only after receiving external excitation signals
such as remote control and buttons. Through excitation by remote control device, internal
signal, the set-top box can return to on mode from this mode.
3.3 passive standby power
under the test methods specified in this Standard, the active power of flat panel
TVs and set-top boxes measured in passive standby mode
3.4 on mode static power for flat panel televisions
under the test methods specified in this Standard, the active power measured
when a flat panel TV is playing a static test image under on mode
3.5 on mode dynamic power for flat panel televisions
under the test method specified in this Standard, the active power measured
when a flat panel TV is playing dynamic test signals under on mode
3.6 on mode power for flat panel televisions
active power used to calculate and evaluate the energy efficiency of flat panel
TVs
NOTE: The on mode power for flat panel televisions is determined from the on mode static
power and the on mode dynamic power, see 6.2.
3.7 fluctuation values of power for flat panel televisions
the ratio of the absolute value of the difference between the on mode static
power and the on mode dynamic power TO the on mode static power
3.8 minimum allowable values of energy efficiency for flat panel
televisions
under the test methods specified in this Standard, the minimum energy
efficiency value and the maximum passive standby power value allowed for flat
panel TVs
The minimum energy efficiency required by minimum allowable values of
energy efficiency for the flat panel television, of which the resolution is not
greater than 1920×1080, is grade 3 of energy efficiency grades in Table 1. The
minimum energy efficiency required by minimum allowable values of energy
efficiency for the flat panel television, of which the resolution is greater than
1920×1080 but not greater than 3840×2160, is grade 4 of energy efficiency
grades in Table 1. The minimum energy efficiency required by minimum
allowable values of energy efficiency for the flat panel television, of which the
resolution is greater than 3840×2160, is grade 5 of energy efficiency grades in
Table 1.
The passive standby power of all flat panel televisions shall be less than or
equal to 0.50W (be round off according to the relevant provisions of GB/T 8170;
keep two significant digits).
For flat panel televisions that use external power, the external power supply
used shall also comply with the minimum allowable values of energy efficiency
in GB 20943.
5.2 Minimum allowable values of energy efficiency for set-top boxes
The minimum allowable values of energy efficiency for set-top boxes is grade
3 of energy efficiency grades in Table 2.
For set-top boxes that use external power, the external power supply used shall
also comply with the minimum allowable values of energy efficiency in GB
20943.
6 Calculation method for energy efficiency
6.1 Calculation of power fluctuation value for flat panel televisions
The power fluctuation value of LCD TV is calculated according to formula (1):
Where,
ΔP - Power fluctuation value, expressed in %;
Pj - On mode static power, in watts (W);
Pd - On mode dynamic power, in watts (W).
Annex A
(normative)
Test methods for energy efficiency for flat panel televisions
A.1 Test environment
A.1.1 Working conditions
Unless otherwise specified, the audio part and video part shall be under on
mode. Various settings shall be adjusted in accordance with A.3.2. If the
adjustment position is different, it shall be explained in the test result.
A.1.2 Ambient conditions
Test under temperature, humidity and air pressure within the following range:
- Ambient temperature: 23°C±5°C;
- Relative humidity: 25%~75%;
- Atmospheric pressure: 86kPa~106kPa.
A.1.3 Power supply
The voltage is AC220×(1±1%)V. The frequency is 50×(1±1%) Hz. The total
harmonic distortion shall not exceed 2%.
A.1.4 Test site
In order to avoid stray light from interfering with the test results, the test shall
be carried out in a dark room and the stray illumination of the dark room shall
be less than or equal to 1lx.
A.2 Test signals
A.2.1 Video...