| Number of series cells | 1 |
| Charge current (Max) (A) | 0.5 |
| Operating Vin (Max) (V) | 6.1 |
| Cell chemistry | Li-Ion/Li-Polymer, Lithium Phosphate/LiFePO4 |
| Battery charge voltage (Min) (V) | 3.6 |
| Battery charge voltage (Max) (V) | 4.6 |
| Absolute Vin (safety rating) (Max) ((V)) | 20 |
| Control interface | I2C |
| Features | BAT temp thermistor monitoring (JEITA profile), BAT temp thermistor monitoring (hot/cold profile), IC thermal regulation, Input OVP, Integrated ADC, Integrated LDO, Power Path |
| Operating Vin (Min) (V) | 3.4 |
| Rating | Catalog |
- Linear battery charger with 1.25-mA to 500-mA fast charge current range
- 0.5% Accurate I2C programmable battery regulation voltage ranging from 3.6 V to 4.6 V in 10-mV steps
- Configurable termination current supporting down to 0.5 mA
- 20-V Tolerant input with typical 3.4-V to 6.2-V input voltage operating range
- Programmable thermal charging profile, fully configurable hot, warm, cool and cold thresholds
- Power Path management for powering system and charging battery
- Dynamic power path management optimizes charging from weak adapters
- Advanced I2C control allows host to disconnect the battery or adapter as needed
- I2C Configurable load switch or up to 150-mA LDO output
- Programmable range from 0.6 V to 3.7 V in 100-mV steps
- Ultra low Iddq for extended battery life
- 10-nA Ship mode battery Iq
- 400-nA Iq While powering the system (PMID and VDD on)
- One push-button wake-up and reset input with adjustable timers
- Supports system power cycle and HW reset
- 16-Bit ADC
- Monitoring of charge current, battery thermistor and battery, input and system (PMID) voltages
- General purpose ADC input
- Always on 1.8-V VDD LDO supporting loads up to 10 mA
- 20-Pin 2-mm x 1.6-mm CSP package
- 12-mm2 Total solution size
The BQ25157 is a highly integrated battery charge management IC that integrates the most common functions for wearable, portable and small medical devices, namely a charger, a regulated output voltage rail for system power, ADC for battery and system monitoring, a LDO, and push-button controller. The BQ25157 has the Input Supply Over Voltage Threshold (VOVP) threshold set to 6.2 V.
The BQ25157 IC integrates a linear charger with Power Path that enables quick and accurate charging for small batteries while providing a regulated voltage to the system. The regulated system voltage (PMID) output may be configured through I2C based on the recommended operating condition of downstream IC?s and system loads for optimal system operation.
The device supports charge current up to 500 mA and supports termination current down to 0.5 mA for maximum charge. The battery is charged using a standard Li-Ion charge profile with three phases: pre-charge, constant current and constant voltage regulation.
The device integrates advanced power path management and control that allows the device to provide power to the system while charging the battery even with poor adapters. The host may also control the power path through I2C allowing it to disconnect the input adapter and/or battery without physically removing them. The single push-button input eliminates the need of a separate button controller IC reducing the total solution footprint. The push-button input can be used for wake functions or to reset the system.A 16-bit ADC enables accurate battery voltage monitoring and can be used to enable a low Iq gauging to monitor battery health. It can also be used to measure the battery temperature using a thermistor connected to the TS pin as well as external system signals through the ADCIN pin. The low quiescent current during operation and shutdown enables maximum battery life. The input current limit, charge current, LDO output voltage, and other parameters are programmable through the I2C interface making the BQ25157 a very flexible charging solution. A voltage-based JEITA compatible (or standard HOT/COLD) battery pack thermistor monitoring input (TS) is included that monitors battery temperature and automatically changes charge parameters to prevent the battery from charging outside of its safe temperature range. The temperature thresholds are also programable through I2C allowing the host to customize the thermal charging profile. The charger is optimized for 5-V USB input, with 20-V absolute maximum tolerance to withstand line transients. The device also integrates a linear regulator to provide a quiet rail for radios or processors and can be independently sourced and controlled through I2C.
