The dual-isolation power and signal current detector based on NXP MM9Z1_638 is applied to the BMS solution

With the rapid development of new energy vehicles in the world and the rapid growth in sales, people’s requirements for the safety and reliability of new energy vehicles are increasing. In addition to researching battery technology and battery management systems, people attach great importance to the safety of battery use, and need to monitor the working status of the battery in real time, and know the battery parameters: voltage, current, temperature, etc. The functional safety level of automobiles is gradually being valued. The current detection module carried by the BMS battery management system detects the current of the entire battery pack in real time. Shiping launched Current Detector based on NXP MM9Z1_638 + Vishay WSBS8518L, which is a dual-isolated current detector for power and signal.

Using the BMS battery management system application, this dual-isolated current detector can already realize real-time current detection. The main platform used in the solution is the NXP battery management chip MM9Z1_638, which is a fully integrated battery monitoring device. The device can perform accurate current measurement through an external shunt resistor, and can provide 4 voltage measurements by using an internal calibrated resistor divider or an external divider. It includes an internal temperature sensor that can be attached to the battery and measure the battery temperature, plus 4 external temperature sensor inputs. Vishay WSB8518L high-precision Shunt resistance is used for accurate current measurement. Its high temperature and low temperature resistance characteristics can well realize the detection function of large current. The wide input range of 9V ~ 50V is suitable for the design of various car models.

► Scenario application diagram

► Showcase photos

► Scheme block diagram

► A screenshot of the current value detected by Demo through the PC

► Core technical advantages

1. Double-isolated current detector for power and signal, used in conjunction with vehicle BMS 2. Modular design, suitable for high-power battery management system 3. Real-time current status feedback to the vehicle ECU via CAN bus as an instant Secondary protection basis 4. Support up to 4 channels of voltage & 1 channel of current simultaneous detection 5. Very low resistance value (100μΩ) and ultra-low temperature coefficient of resistance (TCR): <20ppm/℃, accuracy up to ±5%

► Solution specifications

1. 9~50V wide range operating voltage is suitable for most models 2. Supports high current detection up to ±1500A 3. Supports voltage detection up to ±600V 4. 16-bit ADC (4 voltage ADC + 1 current ADC) 5 . 128 KB flash memory, 8 KB RAM, 4 KB EEPROM 6. Support LIN 2.2/2.1/2.0 protocol and physical interface.