IEC 62637-1:2011 pdf free download – Battery charging interface for small handheld multimedia devices
5.1Charger output capacitance
The capacitance at the charger output causes charging current spikes when the charger’sload is changing. Low-capacitance values are recommended if possible. The maximumcharger output filter capacitor size shall be 1 000 uF with + 20 % ‘tolerance if the chargerVmax-out is less than 7 V. For output voltages of 7,0 v to 9,3 V, the maximum capacitancevalue decreases linearly so that for a 9,3 v charger, the maximum output capacitance shall be700 uF with + 20 % tolerance.The maximum capacitance value is illustrated in Figure 2.
5.3Maximum output ripple voltage
The maximum allowed output ripple voltage with maximum output current of the charger is300 mV RMS for output voltages Vout between 2,5 V and 5,5 V.
The maximum acceptable output peak-to-peak ripple voltage is separated to four frequencyranges.A sum of ripple voltages over the full frequency range 0 MHz to 1MHz is 800 mVep.Ripple voltage shall be measured using 0 kQ to 6 kQ resistive load. During the test all themeasured Vand l values shall be within the voltage / current window of the charger interface.
Note that charging voltage, including ripple, shall not have peak values outside the V/l window(see 5.6) for charger output.
5.5Feel current of AC chargers
The purpose of the feel current specification is not electrical safety but to guarantee aminimum physical sensation felt by the user when connecting the devices to chargers usingthe 2 mm barrel charger interface.
The maximum feel current from AC mains to the mobile device through the charger shall be5 uA when measured as specified in lEC 62637-2.
5.6Charging voltagelcurrent window
The minimum charging current is 300 mA when the voltage is between 2,0 V and 4,65 V.During charging, the current and voltage values at the interface shall not exceed the chargingwindow shown in Figure 6.This means that the charger shall operate inside the window andthe devices shall accept all chargers which operate inside the window.The maximum voltageis 9,30 V and maximum current 950 mA.Below 1 v it is allowed that the current may raise to1,2 A as shown in Figure 6.Below 2 V the minimum current is 100 mA,reducing to 0 mAwhen the voltage drops to o v.
The only case when the charging voltage is allowed to exceed the charging current/voltagewindow is in a load change situation (see 5.2).
5.7 current linearity for chargers
The current linearity requirement is specified in a way that the allowed current change isgiven for narrow voltage range from the middle of the total voltage range, but is sufficient toguarantee adequate linearity also for output voltages below or above the specified range.Themaximum current fluctuation shall be 30 % of the current at 3,5 V when the charger outputvoltage varies from 3,5 V to 4,6 V (for example 500 mA -0,3 ×500 mA = 350 mA) when inputvoltage and ambient temperature stay constant. An example of the current linearityspecification is shown in Figure 7.
6.1 Accessory interfaces
An accessory (for example a desk stand) connected between the charger and the deviceshares energy with that device while taking energy for its own needs. The sharing policyvaries based on the type of accessory and the operating conditions. The accessory shallprovide an interface to the device that meets this 2 mm barrel interface specification, but acurrent allowance of 100 mA is given for the accessory, lowering the recommended minimumcurrent to the device from 300 mA to 200 mA. The interface is indicated with dashed lines inFigure 8.