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The NXP MM9Z1 638 power and signal double isolation current detector is used in BMS

Published time : 2019-04-20
The functional safety level of the car is also gradually taken into account. The current detection module installed in the BMS battery management system detects the current of the entire battery pack in real time. Shiping launched the Current Detector based on NXP MM9Z1_638 +Vishay WSBS8518L, which is a double isolation type Current Detector of power supply and signal.

Solution Introduction

With the hot development trend of new energy vehicles in the world, the sales volume grows rapidly, and people's requirements for the safety and reliability of new energy vehicles are increasing day by day.In addition to the study of battery technology and battery management system, people pay special attention to the safety of battery use, the need for real-time monitoring of the working status of the battery, the immediate knowledge of battery parameters: voltage, current, temperature and so on.The functional safety level of the car is also gradually taken into account. The current detection module installed in the BMS battery management system detects the current of the entire battery pack in real time.Shiping launched the Current Detector based on NXP MM9Z1_638 +Vishay WSBS8518L, which is a double isolation type Current Detector of power supply and signal.

Seping group has a dedicated technical team operating BMS battery management system applications, this double isolation current detector has been able to achieve real-time detection of current.The main platform of the scheme is NXP battery management chip MM9Z1_638, which is a fully integrated battery monitoring device.The device can be used for precise current measurements through an external shunt resistor, and a 4-way voltage measurement can be provided by using an internal calibrated resistance divider or an external partial frequency divider, which includes an internal temperature sensor that can be attached to the battery and measure the battery temperature, plus 4 external temperature sensor inputs.The Vishay WSB8518L high-precision Shunt resistor is adopted for accurate current measurement. Its high-temperature and low-temperature resistance characteristics enable it to achieve the detection function of large current.The wide input voltage range of 9V ~ 50V is suitable for all kinds of vehicle designs.

Scene application diagram


Display photos



Scheme block diagram


Demo detects the current value through a screenshot of the PC display


Core technology advantages

1. Power and signal double isolation current detector, combined with vehicle BMS

2. Modular design, suitable for high power battery management system

3. The real-time current status is fed back to the ECU of the vehicle through CAN bus as the real-time secondary protection basis

4. Simultaneous detection of 4 voltages and 1 current is supported at most

5. A very low resistance (100 mu Ω) and low temperature coefficient of resistance (TCR) : < 20 PPM / ℃, precision up to + / - 5%

Project specifications

Wide working voltage range of 9~50V is suitable for most vehicle models

2. Large current detection up to 1500A is supported

3. Voltage detection up to 600V is supported

4. 16-bit ADC(4-channel voltage ADC+ 1-channel current ADC)

5. 128kb flash memory, 8kb RAM, 4kb EEPROM

6. Support LIN 2.2/2.1/2.0 protocol and physical interface

The keyword

NXP MM9Z1_638 dual isolation current detector BMS 638

Key Components

No. Part Number Manufacturer
1 MM9Z1J638BM2EP NXP
2 MM9Z18V ST
3 MM9Z16V ST
4 MM9Z15V ST
5 MM9Z13V ST
6 MM9Z12V ST
7 MM9Z11V ST
8 MM9Z10V ST