Annex III to Ref. Ares(2015)3438296-19/08/2015 MoU regarding Harmonisation of a Charging Capability for Mobile Phones, June 5th, 2009 Date: Dec 15, 2011 Foreword: Guide on Implementation of Requirements of the Common EPS The MoU Signatories have developed this document which identifies certain problems in applying the standards developed by CENELEC and ETSI for the common charger. Particularly as the display technology has been evolving since the original technical specification undertaken by the MOU parties this guide will be the recommendation for how the initial common chargers placed on the market will comply with the MoU. The MoU Signatories recommend to other parties planning placing common chargers on the market to meet the recommendations of this guide. Scope of EN301489-34 V1.1.1: The scope of this standard may give the wrong interpretation that the standard can be applied to any external power supply with a USB Micro-B or Standard-A connector. The correct application of the standard is to external power supplies as defined in EN62684:2010 to allow presumption of conformity to the EMC requirements under the European EMC and R&TTE Directives. The scope is being clarified in the subsequent versions of this standard. Immunity requirements in EN301489-34 V1.1.1: During the immunity testing at 10V/m and 10 Vrms of the MoU Signatories agrees to that monitoring of the ripple of the output voltage is not critical. The performance criterion for the radiated and conducted field immunity is being clarified in the subsequent versions of this standard. During monitoring of the output voltage it is recommended to use opto-couplers to provide measurement isolation at the output connector/terminals to the measuring equipment. Section 5.4 of EN62684: Clarification of voltage drop caused by the detachable cable: The requirement allows for standard USB cable assemblies to be used and is identical to the requirements of the Cable Assembly Voltage Drop specified in the Table 3-1 USB Electrical, Mechanical and Environmental Compliance Standards of the Universal Serial Bus, Cables and Connectors, Class Document, Revision 2.0, August 2007 Section 5.6 i,ii,iii and iv of EN62684: Switching Frequency Components These requirements are exempted as the MoU Signatories has not identified a testing method giving repeatable and reproducible results across test facilities for these common mode noise requirements. Interested parties amongst the MoU Signatories will undertake work to develop such test method which is expected to be concluded over the next 12 months. Other parties with interest in mobile chargers are welcome to join the work. Based on the outcome of the work and the requirements of the touch screen
Guide on Implementation of Requirements of the Common EPS - 4 Oct 20011 page 2 technology used by the mobile industry it is expected that a proposal to revise the common mode noise specification will be submitted at the same time. To avoid interoperability problems with the common chargers in the market the MoU Signatories agrees and recommend the following assessment for common mode noise: 1) Common mode noise is assessed based on pulses longer than 250 ns and by visual inspection of the whole AC period (see Annex for details) 2) The visual inspection may be aided by applying additional filtering (See Annex for details) 3) A LISN may be used as impedance stabilizer and to filter noise from the AC main voltage source (see Annex for details) Based on the requirements of the touch screen display technology used in mobile devices uninterrupted function of the touch screen during charging can be expected for chargers where the above measured levels are below 2 Vpp. Chargers with levels up to 3 Vpp can cause interruption in the function of touch screen on certain manufacturer devices. Section 5.6 iv of EN62684: AC Voltage Frequency Component Section 5.6 v of EN62684: Occupied bandwidth Section 5.6 vi of EN62684: Maximum amount of slew Section 5.7 of EN62684: Required reliability of receptacles and plugs: Implementation of the USB Standard-A and Micro-B connectors may be subject to market availability of connectors classified as ruggedized. Safety and Protection: The Common EPS must be a Limited Power Source in accordance with EN60950-1 clause 2.5
Guide on Implementation of Requirements of the Common EPS - 4 Oct 20011 page 3 Annex Assessment of Common Mode Noise pulses 1, GREATER THAN 250ns: If the main body of the CMN pulse or any part of its constituent noise (ring, transient over/undershoot etc.) is greater than 250ns, then its amplitude shall be considered, excluding any component of the waveform less than 250ns (see fig. 3). 2, LESS THAN 250ns: If the main body of the CMN pulse or any part of it s constituent noise is less than 250ns, then no amplitude measurement is required. MAIN BODY OF CMN PULSE 250ns Fig.1 - This scope plot depicts how noise or ringing of less than 250ns is ignored during the common mode noise measurement. Fig. 2 - Note that even though the transient is part of the Main Body of the CMN pulse, it s amplitude is disregarded in the over-all common mode noise pulse measurement since the transients width is less than 250ns
Guide on Implementation of Requirements of the Common EPS - 4 Oct 20011 page 4 Main CMN pulse amplitude measured. Main body of the CMN pulse. This portion of the transient is GREATER than 250ns so it is INCLUDED in the CMN pulse amplitude measurement.. Fig.3 - Figure 3 dissects the waveform seen in figure 3a into its constituent components. The main body of the common mode noise pulse is highlighted with a dashed red line. It is this portion of the pulse that would be included in the common mode noise measurement. Zero_rising_crossing Zero_falling_crossing Fig. 4 Scope plot depicting the low frequency AC noise and the common mode noise component (yellow plot): This waveform shows that the highest amplitude common mode noise pulse can be located anywhere between 0 and 360 degrees of the AC mains period.
Guide on Implementation of Requirements of the Common EPS - 4 Oct 20011 page 5 Connections of the LISN: A LISN is typically employed, inter alia, to measure conducted emissions from the AC input ports of electronic equipment. EMC standard EN 301 489-34, section 8.4, refers to EN 55016-2-1 (equivalent to CISPR 16-2-1) for the test method for conducted emissions from the AC mains power input ports of MoUcompliant EPSs. In turn, EN 55016-2-1 requires the use of Artificial Mains Networks, also known as LISNs, specified in EN 55016-1-2 (CISPR 16-1-2). In this context the LISN (a) presents a defined impedance (typically 50 Ω), from live to earth and from neutral to earth, to the mains input port under test, (b) removes incoming (high frequency) noise from the local mains environment using a low pass filter, and (c) provides signals for mains input port conducted emissions measurement from a high frequency output. During the CMN measurements at the DC output of an MoU charger it is recommended also to employ a CISPR 16-compliant LISN (V-type). However its high frequency output is not used. The LISN simply prevents noise present on the mains network from appearing at the input of, and presents 50Ω impedance to the charger. Because this 50Ω resistance appears in series with the far larger 10 MΩ oscilloscope probe resistance, the LISN does not significantly reduce the measured CMN amplitude. The LISN allows either the live or neutral charger input to be bonded to Earth via 50Ω impedance, or to the terminated HF output, which normally presents 50Ω impedance via the EMI receiver input. High frequency noise on the mains inputs is blocked by the HF filter. The unused HF output is terminated to 50Ω. The charger input sees a 50Hz AC voltage source having 50Ω output impedance. There are many manufacturers of CISPR 16-compliant LISNs, including Rohde & Schwarz, Agilent, Schwarzbeck, AFJ, and many more. Upstream of the LISN an optional safety transformer ideally shielded provides extra attenuation of mains-borne high frequency noise. The LISN causes a high current to flow in the earth connection. For safety and measurement accuracy reasons the LISN earth connection must be reliably bonded to the earth connection of the incoming mains supply. The LISN, charger, test load and other components are arranged according to the principles of CISPR 16-2-1, as amended by the requirements of section 6.2 of IEC/EN 62684. CISPR 16-2-1 requires a vertical and/or horizontal measurement ground reference plane measuring at least 2 m x 2 m. It is recommended to employ both of these planes, bonded together. The LISN is connected to either axis of the measurement ground reference plane, either directly to the LISN case, or with a conductor that is as short as possible. A shielded chamber is not required by CISPR 16-2-1. Filter Details: The Guide on Implementation of Requirements of the Common EPS includes the recommendation to measure the CMN pulse generated by the high frequency switching, whilst not considering any ring or component faster than 250 ns. The proposed method employs visual inspection and interpretation of ringing and other high frequency components. Applying an appropriate band pass filter to the common-mode noise signal monitored by the sampling probe could be a more consistent way to select the signals of interest, and to reject these high frequency signals. For example, rejecting components faster than 250 ns might correspond to a filter having a high cut-off frequency of 4 MHz. Such a band pass filter also allows an appropriate low cut-off frequency to be applied. An appropriate band pass filter may therefore be one having a lower cut-off frequency below the switching frequency and an upper cut-off frequency of 4 MHz. Cut-off frequencies are typically defined as those at which the output of the circuit is 3 db of the nominal pass band value. Such filter can be implemented equivalently in hardware, software or as a PC interfaced to the oscilloscope, offering a wide range of filter options.