The design ensures voltage monitoring, helps integration with numerous displays, and offers safety via fuse-blowing mechanisms for security.
Secondary-level protectors at the moment are required for 48V-60V battery methods in industrial functions. The TIDA-00108 reference design from Texas Devices (TI) presents a sturdy stacked structure that ensures high-accuracy voltage detection for 10s-15s collection rechargeable cells. Throughout the bq7718xy household, every cell is monitored independently, that includes an embedded delay timer to stop false tripping of inline fuses. The design applies to numerous industries, together with energy instruments, storage battery safety, and digital car (EV) bikes.
The answer operates independently of current monitoring Analog Entrance-Finish (AFE) and cell-balancing methods, providing seamless integration with 5-, 10-, and 15-series (S) displays and protectors. It offers exact digital management of an correct self-controlled inline present fuse. A key function is the one-time fuse blow mechanism, which completely disables the circuit, isolating the pack and rendering it inoperable for enhanced security and safety.
The secondary stack system reference design consists of three key purposeful blocks. First, the cell enter filters and safety community are outlined based on the bq7718 gadget specs. These filters guarantee correct voltage and present administration on the enter stage. Second, the design incorporates three bq771xx units organized in a stacked 3-S configuration, combining particular person output alerts in a logic OR utilizing an analogue scheme. This serial association helps voltage translation from floor as much as 60V. Lastly, the inline fuse blowing mechanism is electronically managed by an NMOS FET linked to a self-protecting fuse, making certain secure disconnection when mandatory.
The cell banks are emulated in laboratory testing utilizing a cell financial institution simulator. The simulator routes cell voltages via a low-pass filter community designed per the gadget specs, which additionally limits the differential present into the bq7718 gadget. The bq7718 collection independently displays every cell, with an embedded delay timer that forestalls untimely triggering.Â
The gate voltage of the NMOS FET is calculated to vary between 3V and 10V. When activated, the FET pulls the fuse to blow open via the heater resistance of the self-controlled, state-of-the-art fuse, making certain dependable safety. This unit is programmed to use hundreds starting from 3A to 30A, enabling thorough PCB efficiency testing beneath various circumstances.
Key circuit parameters, together with the traditional working present throughout each charging and discharging, the utmost fault voltage, and the secondary safety circuit’s response time to an overvoltage situation, information the collection of the gadget specification. Primarily based on the system’s overvoltage safety (OVP) threshold, output delay timer, and output drive necessities, the secondary safety gadget could be chosen for the design.
TI has examined this reference design. It comes with a invoice of supplies (BOM), schematics, meeting drawing, printed circuit board (PCB) format, and extra. The corporate’s web site has extra knowledge concerning the reference design. To learn extra about this reference design, click on right here.
