Other Parts Discussed in Thread: BQ25798
Tool/software:
Refer to the blcok of attached BQ25856 charging power to be supplied to Li-Battery package and audio amplier product. We are invetigating if it is possible or not that more power to the speaker can be supplied from not only Li-Battery but also Input Charge Power at the same time, and how much total power it can be if possible.
(As an assumption, when the load becomes heavy due to dynamic audio output changing, the expectation is theoretically it can supply a maximum of 84W (8.4V x 10A) from the batt + 60W (12V x 5A, assuming 100% efficiency) from Input Charge power= 144W under the situation of full power battery)
Could you give us the opinion on whether or not it is possible to achieve the expection. Below is our concerns including the charging operation management, pls also check them and let us know the results.
In case of simultaneous supply, the following points are assumed to be checked:
(1) Due to the limited performance of Li-Batt, the max. charge current is less than 2.6A, when voltage rises to Vbatlowv, charge IC supplies constant current (fixed at only 2.6A) output, so there is no more margin for audio amplier, and only Battery can supply 2.6A or less, is this understanding correct?
2) When the voltage rises to Vfb_reg (8.4V), the constant voltage is supplied and the charging current is also lower and lower, then the Charge IC output can supply more power of almost whole power 12V/5A , and synchronously Battery will supply the whole power 8.4V x 10A to amplier for maximum power to achieve the expectation, is it correct and avaible ?
3) If the voltage drops below Vrechg due to load consumption, Charge IC will change to a constant current charging of 2.6A, and once again there will be no margin to the amplier, except the supplying from the battery with only 2.6A.
(4) If the hysteresis between Vfb_reg and Vrechg setting is too small, the operation will become unstable due to repetition of (1), (2), and (3), so we think Vrechg threshold need be setted to same as Vbatlow (3.0V*2=6V) instead of the recommended value of 4.1V*2=8.2V for stable operation, is there any concern? Of course we are assuming that the battery charge often becomes not full.
Ple find the block and charging operation with charge current curve below, we will appreciate very much for your opinion for the whole solution.
