Please help with the following questions,
1- I understand that if
the unit is powered with the DC Voltage Vac the D5 goes on and D4 is on when the
battery is charged through USB. What are the D2 and D3
2- How long does it take a
battery to be charged?
3- I understand that USB
high power it can be set in the control panel. Does this mean that some
computer can not provide the 500 mA through the
4- When do we know that
the battery has been charged completely?
5- Is ther certain battery
that can not be used by this I.C?
By the way my questions are related to the bq24030/1/2/5 EVM.
1. D2 and D3 for STAT1 and STAT2, in datasheet page 24 has a table for status pins summary.
2. It depends on the battery capacity and charge rate.
3. USB spec need first in low power mode, after negotiation it allows draw 500mA.
4. Charger sensing charging current, at first it works in Constant current (CC) mode, when battery voltage reasches voltage set point, it enters into Constant voltage (CV) mode, current tapers down.
When charge current is small than termination current in CV mode, it is considered as charge done. Datasheet page 11 figure 1 gives the charging profile.
5. This IC has CC-CV charging profile, it is designed for single cell Li-Ion or Li-Pol battery.
Thanks for your reply Mao. My question here is choosing the resistors to set the ISET1 and ISET2 depends on the charge rate of a battery? Am I correct?
You need check battery datasheet to get its capacity and max charging current.
Then select charging current based on battery and AC adapter.
AC charging current is determined by ISET1 resistor.
USB charging 100/500mA by ISET2 logic input voltage level.
Would it be correct that I have to choose two differenet resister for the ISET2 if some USB only provides 100mA and some both 100 and 500mA.
ISET2 is not resistor, it is a logic input, <0.4v is logic low, >1.4V is logic high.
Usually it comes from a host GPIO. Host first communicate with USB interface then know the USB current capability, then pull ISET2 pin high or low to set USB input charge current.
Thank you for nice explanation.
Would it be correct then if a logic high is inserted to the ISET2 input pin then the value of rsister chosen between ISET1 and ground be at least capale of handeling charging current of 500 mA.
Charging current is set by ISET1 pin, however if used in USB mode, the ISET2 level limit the max current to 100/500mA.
Datasheet page 13 table 1 has PSEL pin description for every combinations of AC, USB source present or not present.
Usually AC adatper has higher current capability than 500mA.
However, you can set ISET1 lower than 500mA, for example 300mA, then USB 500mA mode only charge at 300mA rate.
My last questions please and thank you for your patients,
PINs 15, 16 and 17 are specified as output terminal to the system. Please elaborate more.
I see that the bq2403x has the Reverse CUrrent, Short Current, and Thermal Protection. Do we need any extera safety protection for the battery from the battery supplier?
Pin 15,16, 17 are LDO output pin, connect together to system to power host, for example, your application is MP3 player, the system means the CPU or any DC/DC LDO or buck, boost converter for memery, LED driver etc.
Battery cell need extra circuit protection for over /under voltage, over charge/discharge current, out of tempearature protection for safety.
Thank you Mao,
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