1. Of course, the more stably the charger produces 5V and the smaller the ripple, the better, because we all use DC for charging. Generally, direct current is converted from alternating current, except for batteries. Ripple is the alternating component of a direct voltage. The DC voltage must originally be a fixed value, but in many cases it is obtained by rectifying and filtering the AC voltage. Since the filtering is not clean, there will nevertheless be residual alternating components, even if it is powered by a battery. , it will always be affected by the load. Waves cause ripples. In fact, even the best voltage reference devices exhibit ripple in their output voltage. Ripple voltage will affect the operation of the system and cause noise. The power supply must therefore have sufficient filtering measures to limiter the ripple to a certain amplitude.
2. Typically, a computer's power supply is converted to 5V, 12V and other voltages required by the motherboard and hard drive via ~220. Power to motherboard chips such as the processor is obtained by converting direct current to direct current. is relatively stable, so it can be used for charging.
3. The lower the output ripple of the lithium battery, the more stable the operation. Therefore, as long as it is a direct current electrical appliance, the smaller the ripple, the better. For example, there are many devices for eliminating ripple in switching power supplies. Used to eliminate ripples
About mobile phone battery voltage problem
When the battery is fully charged, the battery voltage is 3.8-3 .9 V. As the energye is consumed, the voltage. will gradually decrease when the voltage is lower than 3.7V, most mobile phones will automatically turn off. The charging voltage of the mobile phone battery is 4.2V~5.5V. If the battery voltage exceeds 3.92V, it will enter the overcharge protection state. I am a battery engineer.
First of all, there is a relationship between cell phone battery and voltage. The output voltage of the charger can indeed affect the charging current, because neither the charger nor the battery is ideal and has internal resistance, so the battery is connected to the charger Turned on, the maximum loop current is ( V_recharge - V_battery) / (ESR_recharge ESR_battery).
Secondly, the 3.7V marked on the cell phone battery is an average number. Generally, the voltage of cell phone lithium batteries is marked as 3.7V. In fact, the full voltage of the batteriestteries of the mobile phone (hereinafter referred to as). like ordinary lithium batteries) is 4.2. If the battery is used below 3.4V, it will not have much power. If it is lower than 3.4V, it will protect the phone and turn off by itself.
Next, what is marked on the charger is the no-load voltage, which is the voltage when the battery is not switched on. Once the battery is turned on, it will be the same voltage as the battery. , which means the battery voltage increases slowly. After reaching 4.2V, it must be held for a while to allow the battery to be fully charged if the voltage is at 4.2V and there is not much current flowing through the battery. battery. , it is fully charged. If charged more, the battery will be broken.
Finally, the output voltage of the charger is a little higher than the full charge voltage of the battery. If sheis too low, it will not be able to charge the battery or will be very slow.
It is recommended to use the original charger to charge your cell phone. It is best to turn off the phone or not use it when charging. This is good for the mobile phone battery and can be fully charged as soon as possible.