Tool/software:
HI TI Team,
i am trying to charge the battery(11.2V/3A) for this i given supply from RPS(12V/2A). Also communicated with SMBUS and changed the register bits as charge option 0 (020E) and charge current(0800) as per bq25720evm.but my battery is not charging.
Could you please help me on this. below is my log information.
.
Tagore.
HI, Tagore,
The device charges the battery in three phases: pre-charge, constant current, constant voltage. At the beginning of a charging cycle, the device checks the battery voltage and regulates current/voltage accordingly.
For 2S to 4S applications, when the battery voltage is below minimum system voltage VSYS_MIN(), the charger is in pre-charge status. When EN_LDO=1b, charge current is the lower value of 384mA and CHARGE_CURRENT() setting. The 384mA clamp current is to prevent overheating the BATFET. When EN_LDO=0b, the charge current is programed through CHARGE_CURRENT() register.
When the battery voltage is above minimum system voltage VSYS_MIN() and below max charge voltage CHARGE_VOLTAGE(), the charger is in constant current (CC) mode. The charger regulates the charge current at CHARGE_CURRENT() setting. The charge voltage is below CHARGE_VOLTAGE() setting.
When the battery voltage reaches max charge voltage CHARGE_VOLTAGE(), the charger is in constant voltage (CV) mode. The charger regulates the battery voltage at CHARGE_VOLTAGE() setting. The charge current is determined by the charger, which is lower than the CHARGE_CURRENT() setting.
When the charge current drops below termination current (determined by user), the host can stop charging by programming CHARGE_CURRENT()=0.
The battery charging profile is illustrated below.
My suggestion is to lower min system voltage register VSYS_MIN() value to 6V. You could see more charge current.
Regards,
Tiger
Hi Tiger,
I'm using custom board taking the reference from BQ25720_EVM Schematic. Attached Custom board schematic please review
Following is the current hardware setup for testing.
Setup has STM32 EVB, BQ25720 Custom board and 3.7V Li-ion Single cell. STM32 is used to interface custom board over SMBus and following are the Gpio connections.
For Battery IC side
PC10 = ilim_hiz = i/p
PC11 = chrg_ok = o/p
PC12 = otg/vap = i/p
PD2 = cell control= i/p
PC8 = Cmp_out = o/p.
Input supply to setup =12V,10A
Through SMBus Following registers are configured.
1. Vsys_min register = 0x100 (which is set to 100mV),
2.Charge option0 register = 0x020E.
3.Charge current register = 0x0800(which is set to 256mA)
4.Charge voltage register = 0x0800(which is set to default value)
Following the system log which shows setting above 4 registers reading same registers to confirm the values along with other status registers
Could you please share your Feedback.
Thanks & Regards,
Tagore.
