SLUAAA1 October 2021 BQ21061 , BQ21062 , BQ24179 , BQ25150 , BQ25155 , BQ25157 , BQ25672 , BQ25790 , BQ25792 , BQ25798 , BQ25882 , BQ25883 , BQ25887 , BQ25895 , BQ25896 , BQ25898 , BQ25898D
The BQ25155 is a highly integrated battery charge management IC that integrates the most common functions for wearable and portable devices, namely a charger, a regulated output voltage rail for system power, 16 bit ADC for battery and system monitoring, a LDO, and push-button controller. The BQ25155 IC integrates a linear charger with PowerPath that enables quick and accurate charging for small batteries while providing a regulated voltage to the system. The regulated system voltage (PMID) output can be configured through I 2C based on the recommended operating condition of downstream ICs and system loads for optimal system operation.
Tto limit the number of ADC conversions, and hence power consumption, the ADC conversions when in active battery mode can be limited to a period determined by the ADC_READ_RATE bits. In the case where the ADC_READ_RATE is set to manual mode, the host has to set the ADC_CONV_START bit to initiate the ADC conversion. After the ADC conversion is completed and the data is ready, the ADC_READY flag is set and an interrupt is sent to the host. In low power mode, the ADC remains OFF for minimal IC power consumption. The host must switch to active battery mode (set LP high) before performing an ADC measurement.
The BQ25155 allows for the creation of advanced battery monitoring and gauging firmware through its registers. Relevant registers have been listed below in Table 4-1.
Also included in the MSP430 Code Snippet section is an MSP430 code snippet that shows interfacing with the BQ25155.
|
Address |
R or R/W |
Note | |
|---|---|---|---|
| CHRG_CV_STAT | 0x0 | R | Constant voltage charging mode (taper mode) status. |
| CHARGE_DONE_STAT | 0x0 | R | Charge done status. Can be used to force SOC to 100% in FW. |
| CHRG_CV_FLAG | 0x3 | R | Constant voltage charging mode (taper mode) flag. Can be configured as an interrupt to alert host MCU. |
| CHARGE_DONE_FLAG | 0x3 | R | Charge done flag. Can be configured as an interrupt to alert host MCU. |
| BAT_UVLO_FAULT_FLA G | 0x4 | R | Battery under voltage flag. Can be used to force SOC to 0% in FW, threshold configurable from 2.4–3 V. Can be configured as an interrupt to alert host MCU. |
| ADC_READY_FLAG | 0x5 | R | ADC ready flag. Can be configured as an interrupt to alert host MCU. |
| ADC_READ_RATE_1:0 | 0x40 | R/W | Read rate for ADC measurements in BAT Only operation. Can be configured for manual or automatic conversions. |
| ADC_CONV_START | 0x40 | R/W | ADC conversion start trigger. Bit goes back to 0 when conversion is complete. Used for manual reads. |
| ADC_COMP1_2:0 | 0x40 | R/W | ADC channel for comparator 1. Can be configured for VBAT channel. |
| 1_ADCALARM_15:4 | 0x53 | R/W | ADC alarm 1 threshold, can be configured to trigger interrupt when VBAT goes or below specified threshold. If more than one threshold is needed, two more alarms are available (all can be set to watch VBAT). |
| EN_VBAT_READ | 0x58 | R/W | Enable measurement for battery voltage (VBAT) channel. |