Maxim Integrated Debuts a 14-Channel, ASIL-D Compliant Data Acquisition System

The MAX17852 enables manufacturers to formulate systems that meet the tough ASIL-D standards for voltage, current and temperature measurement and communication. 

Image courtesy of Maxim

 

The MAX17852 is focused on safety, and on allowing EVs to get the most mileage out of each battery charge. It delivers highly accurate readings of each battery cell’s current, voltage and temperature and does so with tight time synchronization. 

 

Key Features of the MAX17852 

The MAX17852 provides fast and accurate data for monitoring and controlling the efficiency and heath of individual battery cells and the battery system as a whole. Up to 32 devices can be daisy-chained to manage up to (32 x 14) 448 battery cells 

Cell voltage measurement over a temperature range of 5 to 40℃ is within ±2mV. Over a fuller 

(-40 to 125°C) range, maximum error is 4.5mV

The new data acquisition IC integrates a current sense amplifier, enabling simultaneous acquisition of current information along with cell voltage and temperature. The current sense amplifier features 5mA resolution (Gain = 256). 

The MAX17852 can work with both hall effect sensors and shunt resistors as sensing components.

Maxim asserts that the high level of integration within the device means up to a 16% savings in board space and that the integrated current sense amplifier can provide up to a 20% savings in cost.

As per Tamer Kira, executive director for the Automotive Business Unit at Maxim Integrated, “Enabling systems to achieve the highest level of safety (ASIL D) for a BMS system is really a must for consumers to feel safe in their electrified vehicles.” He goes on to say that, “The MAX17852 is the fastest and most accurate in voltage, current and temperature measurements and that is why it is the first battery data acquisition system in the industry to achieve the highest safety rating for all the major components of a BMS system.” 

 

Further Device Specifications

• Maxim’s battery-management UART or SPI protocol is employed, supporting an I2C interface enabling external device control. To support FEMA (failure mode and effects analysis) and ASIL-D requirements, internal diagnostics and fast-alert communication are made available through both embedded communication and hardware-alert interfaces.
• The MAX17841 is power stingy. In standby mode it draws 2ma, while in shutdown mode, only 2µA is drawn.
• The device features 14 cell balancing switches, with over 300mA of user programmable balancing current. Balancing is automated, and there is an emergency discharge mode
• Safety alerts are individually configurable. These include overvoltage, undervoltage and under-temperature. Additionally, there is a one cell-mismatch alert.

 

Applications

• Battery management systems
• Electric Vehicles (EVs)
• Hybrid Electric Vehicles (HEVs)
• High Voltage Battery Stacks
• Battery-Backup Systems 
• Fuel cell systems
• Supercapacitor Systems
• Electric Bikes
• Battery Powered Tools

 

Physical considerations

• Operating temperature range is from -40 to +125℃
• The unit is available in a 64-Pin (10mm x 10mm) LQFP Package

 

Getting to Market Faster

The MAX17852 evaluation kit (EV kit) will serve to familiarize designers with the MAX17852. It is designed to work in conjunction with the MAX17841B EV kit, which is employed to establish contact with the user’s PC. Thus established, the EV kit is controlled via a GUI on the designer’s PC. It enables engineers to build and familiarize themselves with a BMS controlling as many as 32 daisy chained devices.