STW4102IQT STMicroelectronics, STW4102IQT Datasheet - Page 23

• Manufacturer Part Number: STW4102IQT
• Description: IC LI-ION BATT CHRGR DUAL 24QFN
• Manufacturer: STMicroelectronics

Specifications of STW4102IQT

• Function: Battery Monitor
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 4.25 V ~ 16 V
• Operating Temperature: -30°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 24-QFN
• Product: Charge Management
• Output Voltage: 4.7 V
• Output Current: 100 mA to 1000 mA
• Operating Supply Voltage: 4.25 V to 16 V
• Supply Current: 2 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 30 C
• Mounting Style: SMD/SMT
• For Use With: 497-8514 - BOARD EVAL STW4102/STM32497-8338 - BOARD EVAL BASED ON STW4102
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-6840-2

STw4102
8.2
approximately 250 microseconds must be respected between the time the RD_REQ bit is
set and the actual register reading. The RD_REQ bit is automatically cleared after the
transfer.
A high value written to the RST_CHRG, RST_DCHRG or RST_COUNTER bits of the
control register resets respectively the charge accumulator, discharge accumulator or
conversion counter. If these bits are set together with the RD_REQ bit, then the reset occurs
after the transfer to the charge, discharge or conversion counter register respectively. The
RST_CHRG, RST_DCHRG or RST_COUNTER bits are automatically cleared after the
reset.
The differential inputs are scaled to the full range of the AD converter, introducing a small
offset error. A high value written to the CG_CAL bit of the control register connects the
inputs of the AD converter together, allowing the DBB to measure the digital offset error.
Using this measurement, the gas gauge can be calibrated to reduce the offset error.
The conversion cycle of a 12-bit plus 1 sign-bit AD converter is 2
Using the 32.768kHz RTC clock, the conversion cycle time is 250 ms. The LSB value is
23.54 µV, which corresponds to a current of 784.7 µA with a typical 30 mΩ sense resistor.
Given a 250 ms conversion cycle time, this LSB value corresponds to a charge of 54.5 nAh.
Under these conditions, the 24-bit accumulator has a capacity of 914 mAh.
The gas gauge system is disabled when the battery voltage is below the Power On Reset
threshold (2.7 V), or when the RESETN pin is driven low (CG_ENA bit default value is 0).
During normal operation, either the STDBY pin or the CG_ENA bit can be used to disable
the gas gauge function. When the STDBY pin is low, the gas gauge is disabled without
waiting for the end of the current conversion. When the CG_ENA bit is low, the current
gauge is disabled at the end of the current conversion.
Battery voltage monitoring
The battery voltage can be measured by means of a 7- or 12-bit A/D converter. This function
is enabled and configured using the following bits of the ADCTRL register:
●
●
●
●
●
A high value written to the ADCAL bit of the control register connects the input of the A/D
converter to ground, allowing the DBB to measure the digital offset error. Using this
measurement, the AD converter can be calibrated to reduce the offset error.
The conversion cycle of a 7 (12) bit conversion is 2
32.768kHz RTC clock, the conversion cycle time is 7.8 (250) ms. LSB value is 45 (1.4) mV.
When the battery voltage falls below the Power On Reset threshold, or when the RESETN
input is driven low, the battery voltage monitoring function is disabled.
The ADPOWERON bit enables battery voltage monitoring.
The ADRESOLUTION bit allows to select 7- or 12-bit conversion.
The ONSTATE bit is set when the ADC converter is ready.
The ADSTART bit starts a conversion; it is automatically cleared after writing.
The ADRUN bit indicates that a conversion is in progress. The result is available when
the ADRUN bit goes low, and it can be read in the ADDATA registers.
8
=256 (2
13
=8192) clock cycles. Using the
13
(8192) clock cycles.
Battery monitoring
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