I have a design which includes the bq27531-G1 battery management chip and the bq24192 charger chip. This is part of a handheld device powered by a 3200mAh polymer lithium ion battery (the bq chips are part of the system, not the battery pack). The circuit is straight out of the datasheet for the bq27531.
With our first revision prototype, we are unable to connect the I2C bus in order to run the calibration routines from a PC using the bq eval software. Plus, I understand it's problematical anyway when the gas gauge and charger are part of the system powered by the battery. I can read and write registers from the micro on the board.
However, we still expected to see some level of charging happen, without having to program the gas gauge. We see nothing at all while the system is running (with USB power connected). If we put the system to sleep (which drops current draw down to ~6mA), then we see a small trickle charge of ~80 mA).
Should I see some charging (even when the system is running and drawing ~200mA)? Are there some registers I have to poke in the bq27531 in order to get it to start? Here's a dump of all the registers:
00 Control: 0000 CONTROL_STATUS = 0x0284 644
00 Control: 0001 DEVICE_TYPE = 0x0531 1329
00 Control: 0002 FW_VERSION = 0x0102 258
00 Control: 0003 HW_VERSION = 0x00a8 168
00 Control: 0007 PREV_MACWRITE = 0x0003 3
00 Control: 0008 CHEM_ID = 0x1202 4610
00 Control: 001f DF_VERSION = 0x0000 0
02 AtRate = 0x0000 0 mA
04 AtRateTimeToEmpty = 0xffff 65535 Minutes
06 Temperature = 0x0b95 2965 0.1 K
08 Voltage = 0x0e69 3689 mV
0a Flags = 0x0139 313 hex
0c NominalAvailableCapacity = 0x0659 1625 mAh
0e FullAvailableCapacity = 0x090b 2315 mAh
10 RemainingCapacity = 0x069d 1693 mAh
12 FullChargeCapacity = 0x0943 2371 mAh
14 AverageCurrent = 0xfee3 65251 mA
16 TimeToEmpty = 0x018d 397 Minutes
18 RemainingCapacityUnfiltered = 0x0679 1657 mAh
1a StandbyCurrent = 0xfff6 65526 mA
1c RemainingCapacityFiltered = 0x069d 1693 mAh
1e ProgChargingCurrent = 0x0000 0 mA
20 ProgChargingVoltage = 0x0000 0 mV
22 FullChargeCapacityUnfiltered = 0x092b 2347 mAh
24 AveragePower = 0xfbe5 64485 mW
26 FullChargeCapacityFiltered = 0x0943 2371 mAh
28 StateOfHealth = 0x0160 352 % / num
2a CycleCount = 0x0004 4 Counters
2c StateOfCharge = 0x0048 72 %
2e TrueSOC = 0x0047 71 %
30 InstantaneousCurrentReading = 0xfedd 65245 mA
32 InternalTemperature = 0x0b8c 2956 0.1 K
34 ChargingLevel = 0x0000 0 hex
6e LevelTaperCurrent = 0x0000 0 mA
70 CalcChargingCurrent = 0x0000 0 mA
72 CalcChargingVoltage = 0x0000 0 V
74 ChargerStatus = 0x08 8
75 InCtrl_Reg0 = 0x00 0
76 POR_Config_Reg1 = 0x00 0
77 Current_Reg2 = 0x00 0
78 PreTerm_Reg3 = 0x00 0
79 Voltage_Reg4 = 0x00 0
7a TermTimer_Reg5 = 0x00 0
7b IRThermal_Reg6 = 0x00 0
7c OpCtrl_Reg7 = 0x00 0
7d Status_Reg8 = 0x00 0
7e Fault_Reg9 = 0x00 0
7f Rev_RegA = 0x23 35
Thanks in advance for any guidance you can provide,
--mkj