Battery-powered systems—including power tools, electric vehicles wearable electronics, IoT edge devices and more—depend on the proper managing of battery power. To keep pace, all sorts of innovations have been happening in power management ICs, battery monitoring ICs and more.
There are many facets to managing power and batteries in embedded systems. Increasing battery life and efficiency is a major goal for a variety of embedded system. Analog IC vendors are smoothing the way with innovative chips for monitoring, controlling and charging batteries. Over the past 12 months, analog ICs vendors have rolled out several innovative solutions both for portable, battery-powered systems and for the particular needs for electric vehicle battery management.
The latest crop of power management ICs (PMICs) includes devices that combine multiple functions into a single device to reduce the component count and board space needed to easily and cost-effectively manage power in a wide variety of devices. Meanwhile, the latest battery management ICs maximize battery capacity, extend battery life and monitor the charging process. They support a variety of battery chemistries and feature low-cost and high-accuracy voltage regulation solutions that require few external components thereby reducing design size, cost and complexity.
In an example application, in 2018 Maxim Integrated announced that its single-chip, ASIL D-rated battery monitoring IC was being integrated into the Nissan LEAF, the company’s zero-emission electric vehicle (Figure 1). The battery monitoring IC meets the highest safety standards, supporting ISO 26262 and ASIL D requirements (also applicable for ASIL C). Its differential universal asynchronous receiver/transmitter (UART) using capacitive isolation reduces BOM costs and failure in time (FIT) rates. The flexible UART enables robust communications in noisy environments. Using Maxim’s proprietary daisy-chain architecture and successive-approximation-register (SAR) ADC, the battery monitoring IC captures fast, accurate voltage measurements and delivers high electromagnetic capability (EMC) performance.
PUBLISHED IN CIRCUIT CELLAR MAGAZINE • FEBRUARY 2021 #367 – Get a PDF of the issue
18-Cell Battery Monitor Has Daisy Chain Link
Analog Devices' ADBMS1818 is a multicell battery stack monitor that measures up to 18 series connected battery cells with a total measurement error of less than 3.2mV. The cell measurement range of 0V to 5V makes the ADBMS1818 suitable for most battery chemistries. All 18 cells can be measured in 290μs, and lower data acquisition rates can be selected for high noise reduction.
• Measures up to 18 battery cells in series
• 3.2mV maximum total measurement error
• Built-in isoSPI interface
• 290μs to measure all cells in a system
• Configurable as an I2C or SPI master
• 6μA sleep mode supply current
• 64-lead eLQFP package
Auto-Grade Buck Converter Boasts High Efficiency
The DA9130-A from Dialog Semiconductor is a high efficiency, automotive grade, 10A, dual phase, step down DC-DC (Buck) converter with integrated switching FETs. The device can operate at efficiency levels above 90%, reducing the thermal design challenges of powering high current rails in a wide range of automotive systems.
• 2.5V to 5.5V input voltage
• 0.3V to 1.9V output voltage
• 4MHz nominal switching frequency
• ±1% accuracy (static); ±5% accuracy (dynamic)
• I2C -compatible interface (FM+)
• Programmable GPIOs
• Voltage, current and temperature supervision
• -40°C to +105°C ambient temperature range
• AEC-Q100 Grade 2 qualified for automotive
Monitoring IC Targets Li-ion Batteries
Infineon Technologies' TLE9012AQU is a multi-channel battery monitoring and balancing system IC designed for Li-Ion battery packs used in many applications on the automotive, industrial and consumer systems. The IC does cell voltage measurement, temperature measurement, cell balancing and isolated communication to main battery controller.
• Monitors up to 12 series connected cells
• Supports communication of up to 20 devices
• Supports hot plugging
• 16-bit high-res ADC measurement for each cell
• Built in noise filtering
• Selectable measurement bit length
• Internal temperature measurement and monitoring
• Integrated balancing switch
• Communication Interface (iso UART)
Tiny SIMO PMIC Features High Power Density
The MAX77655 from Maxim Integrated provides a highly-integrated power supply solution for low power applications where size and efficiency are critical. Also, it features a single-inductor, multiple-output (SIMO) buck-boost regulator that provides four independently programmable power rails from a single inductor to minimize total solution size. It's capable of delivering a total of 700mA output current (3.7VIN, 1.8VOUT).
• 4x output, SIMO buck-boost regulator
• Output voltage range from 0.5V to 4.0V
• 6.9μA typical IQ with two outputs enabled in low-power mode
• 700mA output current at 3.7VIN and 1.8VOUT
• Up to 90% efficiency
• I2C compatible interface
• 3.95mm2 wafer-level package
PMIC Integrates Three Buck Regulators
Microchip Technologies' MCP16501 is a cost and size optimized integrated PMIC, compatible with the latest Microchip microprocessors and associated DRAM Memories. The MCP16501 integrates three DC-DC buck regulators and one auxiliary LDO and provides a comprehensive interface to the MPU. All buck channels can support loads up to 1A and are 100% duty cycle capable.
• Input voltage: 2.7V to 5.5V
• Three 1A output current buck channels
• One auxiliary 300mA LDO linear regulator
• Pin-selectable output voltages for DDR supply
• Built-in channel sequencing, safe start-up and reset assertion delay
• Support of hibernate and low-power modes
• 24-pin 4mm × 4mm QFN package
• -40°C to +125°C junction temperature range
PMICs Deliver Scalable Control and Simplified Safety
The FS26 from NXP Semiconductors is a family of automotive safety SBC (system basis chip) devices with a multiple power supply designed to support entry and mid-range safety MCUs like NXP's S32K3 series while maintaining flexibility to fit other MCUs targeting automotive electrification. FS26 features multiple switch mode regulators as well as LDO voltage regulators.
• 40VDC maximum input voltage
• Handles severe cranking operation (3.2V battery)
• Low Power Off mode with very low sleep current (35μA typ.)
• Low Power Standby mode, VPRE active
• Multiple switch mode regulators
• Scalable portfolio from ASIL B to D
• ABIST on demand
• Independent monitoring circuitry
IC Manages 14 Series-Connected Li-ion Cells
Renesas Electronics' ISL78714 automotive grade Li-ion battery manager IC supervises up to 14 series connected cells and is optimized to meet stringent automotive performance, reliability and safety requirements. The device provides accurate cell voltage and temperature monitoring, cell balancing and extensive system diagnostics.
• Monitors and manages up to 14 Li-ion cells
• Supports all standard Li-ion cell chemistries
• Supports ASIL D systems
• Two-wire daisy chain communications
• High security comms per ISO26262
• Cell voltage measurement accuracy
• 1.65V to 4.28V; -20°C to +85°C
• Initial Device accuracy: ±2mV
• Post board assembly device accuracy: ±2.5mV
IC Does Fast 50W Qi Wireless Charging
STMicroelectronics' STWLC88 is a highly integrated wireless power receiver solution suitable for applications up to 50W. The chip has been designed to support the latest Qi specifications for inductive communication protocol with Extended Power Profile (EPP) and proprietary STSuperCharge (STSC) protocol for fast charging.
• Up to 50W output power
• Up to 12W output power in Tx mode
• Qi EPP 1.2.4 inductive wireless protocol compliant
• Integrated 27V synchronous rectifier with ≥ 98% efficiency
• LDO linear regulator with output current and input voltage control loops
• Programmable LDO regulator with output voltage up to 20V in steps of 25mV
• 32-bit, 64 MHz Arm Cortex MCU core
• RAM/FTP firmware patching and advance features
• I2C Slave, Master interface
ABuck-Boost Charger ICs Enable High Efficiency
Texas Instruments' BQ25792 is a fully integrated switch-mode buck-boost charger for 1-4 cell Li-ion batteries and Li-polymer batteries. The integration includes 4 switching MOSFETs (Q1, Q2, Q3, Q4), input and charging current sensing circuits, the battery FET (QBAT) and all the loop compensation of the buck-boost converter.
• Buck-boost charger for 1-4 cell batteries
• Supports any USB PD 3.0 profile
• Integrates four switching MOSFETs, BATFET
• Integrates input and charging current sensing
• 750kHz and 1.5MHz switching frequencies
• 5A charging current with 10mA resolution
• 96.5% efficient: 16V battery at 3A from 20V
• 3.6V to 24V wide input operating voltage
• Dual-input power mux c