If you want to identify the quality of the charger product, you can choose from three aspects: its working performance, safety requirements and electromagnetic compatibility:
1. Appraisal of work performance. Different types of batteries have different charging requirements. The charger mainly has parameters such as charging method, charging current, and charging voltage.
(1) Charging mode: It is specified that the charger is to charge the battery in a constant current mode or a constant voltage mode. For the currently commonly used lithium-ion batteries, the charging method of the charger should adopt the current-limiting and constant-voltage method, that is, the current-limiting charging is first performed until the battery limits the charging voltage and then the battery can be automatically converted to constant voltage charging.
(2) Charging current: specifies the maximum output current of the charger. The size of the charging current should match the capacity of the applicable battery, and generally should not be greater than 1C5A.
(3) Charging voltage: The maximum output voltage of the charger is specified. The charging voltage depends on the charging limit voltage of the battery; when charging a lithium-ion battery with a nominal voltage of 3.6V, the highest voltage required by the charger is generally 4.2V (in fact, lithium-ion batteries for mobile phones are equipped with protection Therefore, the output voltage of the charger can also be slightly higher than 4.2V, but in order to ensure safety, the voltage must not be higher than 4.5V).
2. Safety requirements. Generally speaking, it is required that the circuit structure, mechanical structure and electrical performance of the product should meet certain safety requirements, regardless of whether the product is in normal working state or abnormal (such as output overload or short circuit, internal component failure or circuit failure, etc.). The state should not endanger the safety of people and property.
3. There are also aspects of electromagnetic compatibility. For charger products, the electromagnetic compatibility requirements are mainly reflected in electromagnetic disturbance. Electromagnetic disturbance is divided into conduction disturbance and radiation disturbance. Due to the many advantages of switching power supply, switching power supply circuits are commonly used in chargers. However, the high-frequency turn-on and turn-off of the switching devices in the switching power supply will generate high-frequency harmonic signals. These high-frequency signals propagate through the power supply terminal through the power grid or radiate through space, which will bring electromagnetic pollution to the environment, harass the normal operation of surrounding electronic equipment, and seriously may cause adverse effects on the safe operation of the power grid and human health. Therefore, in order to reduce the electromagnetic pollution of the environment, the disturbance voltage and the radiated disturbance field strength of the power terminal (or interface terminal) of the electronic product should be less than a certain limit when it is working.