How to choose battery charging management chip

著者：Iflowpower – Dodavatel přenosných elektráren

Electronic products, especially electronic products that should be carried with you, will use lithium-ion batteries that will be power management for lithium-ion batteries, which will involve lithium-ion battery charging, discharge, voltage testing process. Battery power hardware test. We designed products because the accuracy requirements of the battery voltage are not high, and the internal ADCs in the microcontroller are used, and the reference voltage also supplies the voltage to the microcontroller.

In general, 3.3V is used as the reference voltage. For the voltage test of the lithium ion battery, since the lithium ion battery voltage can be up to 4.

2V, if the outer charge is even 5V or 6V voltage, the single-chip full range is 3.3V, so the two resistors are used in series, single-chip microcomputer The voltage to collect the voltage resistor end is calculated to calculate the voltage value of the lithium ion battery in progressive pressure ratio. Software ADC acquisition section, each single-chip configuration is different, the accuracy is different, here is assumed to calculate the formula, 12-bit ADC a total of 4096th order, assuming that the voltage dividing resistance is two 100K resistors, if it is collected The ADC value is 1234, then the collected voltage value is: 2345 multiplied by 2 times by 2 times by dividing the coefficients, and then divided by 4096 steps, the voltage value is 3778mV.

Formula: Battery voltage = (Current Collection Value * Pressure Value * Reference Voltage) / ADC Delivery. Battery charging management chip selection actually charged the chip brand, we often consider the chip stability, charging current size, charging voltage range, and chip costs to comprehensively consider. We can use the SGM4056 of the Holy Bang, if the battery capacity is not large, can be controlled within 350mV, this chip can also supply charging overflowing feedback pins.

What is the allegation to a single-chip microcomputer?. Single chip microcomputer software's management microcontroller for lithium ion batteries is able to distinguish, not charging, charging, charging. How do these three large batteries? When the lithium ion battery is not charged, the single-chip system does not have an external charger, and the voltage collected by the microcontroller will not exceed 4.

3V. Range within the battery cutoff voltage ~ 4.2V.

When the outer charge is charged, the test is greater than 4.3V, and the charging process is. The single-chip system is in charge, and when the pin level of the charging management chip pin changes, if it becomes a high level, it means that the charging is full, and each brand's charging feedback signal may be the same, please refer to the corresponding specification.

During the normal use of the discharge process, voltage collection is also judged, and the over-displacement of the alert voltage is damaged by the battery or battery protection. Generally, 3.4V is used as the threshold value, which is less than 3.

4V to trigger battery power alarm. Data should be selected in combination with product characteristics. .