New Industry Products

Battery Management Reference Designs Speed EVs to Market

May 02, 2019 by Scott McMahan

Texas Instruments (TI) introduced fully-tested reference designs for battery management and traction inverter systems along with new analog circuits with advanced monitoring and protection features aid in reducing carbon dioxide emissions and enable hybrid EVs and EVs to drive farther and longer.

More Accurate Battery Monitoring and Reduced Time to Market

Scalable across six to 96-series cell supervision circuits, TI's new battery management system (BMS) reference design, TIDA01537 uses the BQ79606A-Q1 precision battery monitor and balancer. In addition to being useful for EV and hybrid EVs, TIDA01537 can be used for industrial energy storage.

Features of BBQ79606A-Q1

  • Qualified for automotive applications
  • AEC-Q100 Qualified with the following results:
    • Device temperature grade 2: -40°C to +105°C ambient operating temperature range
    • Device HBM ESD classification level 2
    • Device CDM ESD classification level C4B
  • Voltage monitor, temperature monitor and communication functions: SafeTI™-26262 ASIL-D compliant
  • ±1.1mV Cell voltage measurement accuracy with an offset
  • Configurable digital low pass filter as low as 1.2Hz
  • Supports simultaneous cell voltage measurements
    • Full-accuracy stack measurements in less than 1 ms (for 96 cells)
  • Optional ring architecture to ensure stack communication even with communication cable break
  • Monitors 3 to 6 cell connections and up to 6 NTC/auxiliary channels
    • Integrated 16-bit analog-to-digital converters (ADC)
  • Integrated high-voltage AFE filter components
  • Designed for robust hot-plug performance
  • Stackable configuration up to 64 devices (1 base + 63 stack, 384-series cells)
  • Isolated differential daisy chain communication
    • Supports transformer or capacitor based isolation
  • Configurable SINC3 digital filter
  • Integrated hardware protector
    • Secondary protection for cell overtemperature and undertemperature
    • Secondary protection for cell overvoltage and undervoltage
  • Hardware protector function: SafeTI™-26262 ASIL-B compliant
  • Integrated cell-balancing MOSFET's up to 150mA
  • Designed to pass BCI testing
  • UART Host interface

This reference design is a small-sized cell supervision demonstrator design for a centralized battery management system (BMS). Its configurable capacitive isolation daisy chain solution enables monitoring and protecting cells ranging from 6-series to 96-series, which allows its use in BMS systems ranging from 24V to 400V.

TIDA01537 Reference design for battery management and traction inverter systems

In hybrid or EVs, a high voltage lithium-ion battery stores the energy required for traction and housekeeping. The battery's lithium-ion cells have to be monitored while charging and discharging. This design provides a solution for monitoring lithium-ion cell voltages accurately and communicating the data externally via various interfaces such as CAN and bqStudio.

TI says automotive designs can get to market quickly using the reference design. The design implements the battery monitor in a daisy chain configuration to create a highly accurate and reliable system for three- to 378-series, 12V and up to 1.5kV lithium-ion battery packs.

BQ79606A-Q1 accurately monitors voltage levels and temperature and helps maximize battery life and time on the road.

Safe-state communication helps it meet requirements up to Automotive Safety Integrity Level D (ASIL D), which is the highest functional safety goal defined by the ISO 26262 road vehicles standard.

TIDA01537 block diagram (Click on image to enlarge)

Features of TIDA01537 Reference Design

  • Scalable cell supervision circuits from 6s to 96s
  • Accurate cell voltage measurements
  • Onboard PMIC diagnosis
  • Onboard BQ79606A-Q1 diagnosis
  • Onboard capacitive isolation
  • Robust hot-plug performance
  • 500 kbps external CAN communication

Reliable Thermal Management

With many kilowatts of power filtering through an electric vehicle's traction inverter and batteries, high temperatures could damage expensive and sensitive powertrain elements. Outstanding thermal management of the system is critical to vehicle performance and to protect drivers and passengers.

The TMP235-Q1 precision analog output temperature sensors protect powertrain systems such as a 48V starter generator from overheating. This low-power, low-quiescent-current (9µA) device offers high accuracy (±0.5°C typical and ±2.5°C maximum across the full operating temperature from -40°C to 150°C) to help traction inverter systems react to temperature surges with the application of the appropriate thermal management techniques.

Features of TMP235-Q1

  • AEC-Q100 qualified for automotive applications
    • TMP235-Q1 grade 0: -40°C to +150°C
    • TMP236-Q1 grade 1: -40°C to +125°C
  • Tight accuracy across a wide temperature range:
    • ±2.5°C (Max): -40°C to +150°C (TMP235-Q1)
    • ±2.5°C (Max): -10°C to +125°C (TMP236-Q1)
  • Positive slope sensor gain, offset (typical):
    • 10mV/°C, 500mV at 0°C (TMP235-Q1)
    • 19.5mV/°C, 400mV at 0°C (TMP236-Q1)
  • Wide operating supply voltage range:
    • 2.3V to 5.5V (TMP235-Q1)
    • 3.1V to 5.5V (TMP236-Q1)
  • Short-circuit protected output
  • Low power: 9µA (typical)
  • Strong output for driving loads up to 1000pF
  • Available package options:
    • 5-pin SC70 (DCK) surface mount
    • 3-pin SOT-23 (DBZ) surface mount
    • Footprint compatible with industry-standard LMT8x-Q1 and LM20 temperature sensors
  • Cost-effective alternative to thermistors

Protection Without Sacrificing Space

The TMP235-Q1 temperature sensing device joins TI's recently released UCC21710-Q1 and UCC21732-Q1 gate drivers in helping create smaller, more efficient traction-inverter designs. The first isolated gate drivers to integrate sensing features for IGBTs and SiC field-effect transistors, these devices can improve system reliability in applications operating up to 1.5kVRMS. These devices offer superior isolation surge protection exceeding 12.8kV with a specified isolation voltage of 5.7kV. They also offer fast detection times to protect against over-current events while ensuring safe system shutdown.

TI has released a new reference design, TIDA-020014 to power the new gate drivers directly from a car's 12V battery. It demonstrates three types of IGBT/SiC bias-supply options for traction inverter power stages. The design consists of over- and under-voltage protection circuits, reverse-polarity protection, and electric-transient clamping.

TIDA-020014 Block Diagram (Click on image to enlarge)

The compact design includes the new LM5180-Q1, which is a 65-V primary-side regulation flyback converter with a 100-V, 1.5-A integrated power MOSFET.

Features of LM5180-Q1

  • AEC-Q100-qualified for automotive applications
    • Device temperature grade 1: -40°C to 125°C ambient temperature range
  • Designed for reliable and rugged applications
    • Wide input voltage range of 4.5V to 65V
    • Robust solution with only one component crossing the isolation barrier
    • ±1.5% total output regulation accuracy
    • Optional Vout temperature compensation
    • 6ms internal or programmable soft start
    • Input UVLO and thermal shutdown protection
    • Hiccup-mode overcurrent fault protection
    • -40°C to +150°C junction temperature range
  • Integration reduces solution size and cost
    • Integrated 100V, 0.4-Ω power MOSFET
    • No opto-coupler or transformer auxiliary winding required for Vout regulation
    • Low EMI operation to meet CISPR 25
  • High-efficiency PSR flyback operation
    • Quasi-resonant switching in boundary conduction mode (BCM) at heavy load
    • External bias option for improved efficiency
    • Single- and multi-output implementations

Features of TIDA-020014

  • Traction-inverter, single-phase, power-stage design includes dual-channel isolated gate driver, isolated DC bus voltage sensing, and isolated temperature sensing
  • Three types of SiC/IGBT bias-supply solutions for IGBT/SiC isolated gate drivers
  • Wide-VIN converters over the input voltage of 4.5Vdc to 42Vdc
  • Output configurable as +15V, -8V or +20V, -4V at loads up to 180mA for driving Si IGBT and SiC MOSFET modules
  • Primary-side regulation with no optocoupler for extended lifetime and small form factor

Availability and Pricing

Pre-production samples are now available in the TI store. The table lists pricing and package type.

(Click on chart to enlarge)