How to choose a suitable charging management chip
Time:2022-05-21
Views:2411
In intelligent electronic products, fast charging has become a hot topic. From charger design to charging management chip, it has become the focus of attention. So how to choose a charging management chip suitable for your own products? Let today‘s quick charge and discharge class tell you. As long as these small problems are solved, a high-performance fast charging product can be easily manufactured.
Charging IC selection is a systematic problem
Input power diversity
Charging IC selection is a systematic problem
The selection of charger should consider the needs other than battery voltage and charging current, such as the needs of power supply path management and battery management of the system, such as cold, heat and safety, and the needs of the system for the characteristics of charging circuit, such as interference and charging speed, so as to make it a system problem.
BAJ / JEITA extended charging suggestions
If the full voltage of the battery is properly increased within the range of 10 ℃ ~ 45 ℃ or the appropriate temperature recommended by the battery factory, the energy storage can be increased by about 5% without affecting the safety and service life. BAJ / JEITA recommends that the waist skin temperature of the battery shall prevail.
How to deal with non battery and weak battery
How to ensure that some or all of the system functions can work when there is no battery, whether to maintain the system when the battery voltage is low and cannot withstand high current, and how to cooperate and work together when the load capacity of the battery or external power supply is low and cannot meet the needs of some functions.
Input power diversity
Any connected similar power supply can work as much as possible, and different overcurrent protection designs of the power supply need to be taken into account, such as constant power protection, maximum output current fallback and shutdown trigger. Except for the last case, limiting the minimum input voltage can maintain effective operation.
Dynamic current distribution and bridging needs
When the external power supply capacity is limited, sacrifice the charging current and give priority to ensuring the power consumption of the system, that is, dynamic current distribution. When multiple ports are connected to the charging power supply and the discharging load respectively, the charging power supply forms a bridge to directly supply power to the load, and the battery supplements power supply when the charging power supply is insufficient.
Requirements for indication or display
Keeping the indicator on for a long time after filling causes unnecessary power consumption and light pollution. Intermittent indication design is adopted during charging of weak power supply, which can make full use of energy and avoid the instability of weak control power supply from affecting the display pattern characteristics.
Where is the local load connected?
It is directly connected to the battery. Before the battery is separated, it may be connected to the load at the external power access point. Use the reverse boost of the charging power supply for OTG or other high voltage applications, such as horn or flash lamp. Which load should be guaranteed first and how.
Switch or linear
First of all, the allowable heating degree should be considered, followed by the heat dissipation capacity of the chip. In addition to energy collection applications, efficiency is considered only because it is related to heating. For small devices, the final heating limit is the heat dissipation capacity of the device, and then the chip heat dissipation is considered.
USB PD, type-C and OTG
Neither PD nor type-C supports the ID pin function of OTG. PD needs complex communication to establish power supply relationship. Type-C explains its role through resistance termination on CC pin. Type-C is the most concise. It is necessary to determine who can identify CC termination and decide power supply / consumption.
Battery disengagement or charge fallback hold
After the battery is fully charged, the battery is disconnected from the charging power supply, so that the battery will not be in the high-voltage charging state for a long time, which is conducive to prolonging the battery life, but increases the loss and cost caused by the disconnection switch. Fallback maintains long battery life at the expense of some capacity.
Characteristics of photovoltaic and weak control power supply
When the output capacity of photovoltaic power supply decreases, it can draw back current from the load, which requires precise anti recharge design. The no-load high voltage of weak control power supply may lead to overvoltage protection, and the short-term supply is unstable. The parameter setting and display shall be stable.
Meet the needs of electricity metering
The OCV method can determine the relative current of the battery and give the expectation of battery life time only by voltage measurement and voltage change in a short period of several minutes. Cooperate with accurate short-term charge measurement, such as current integration or accurate current charging and discharging to obtain the quantitative value of electricity.
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