The LTC6804 is the third generation multi-battery monitor released by Lmear in 2012. It can measure the voltage of up to 121 and serially connected batteries almost simultaneously, and has a lower total measurement error than the LTC6803 measurement accuracy. This article is based on the chip, supplemented by a thermal resistance temperature sensor to achieve multi-channel temperature acquisition, with the company's STM32F103 microcontroller to achieve a single module of the battery management system module to achieve 24 single-cell battery charge and discharge voltage monitoring (two pieces of LTC6804) and 16 The temperature of the road is collected and supports the CAN bus. This paper introduces the design scheme in two parts: voltage and temperature acquisition and control communication. The voltage and temperature acquisition part of a single battery management system consists of two LTC6804, two LTC1380 (8 multiplexed MUX chips) and one LTC6820 (communication chip with ECU). For the LTC6804-1, multiple devices are daisy-chained, one main processing The device is connected through the device; for the LTC6804-2, multiple devices are connected in parallel to the microprocessor, and each device is individually addressed. This article uses LTC6804-1. They communicate with each other using the isoSPI protocol. LTC6804 with isolation transformer and twisted pair can have very good anti-interference ability, so that a microprocessor can manage enough LTC6804 nodes, but to ensure the reliability of the whole system module, avoid single in the serial loop. After the node fails due to some factors, the microprocessor cannot control the node, so the node uses a microprocessor to control the two nodes. The microprocessor uses the BMS internal CAN bus to communicate. The single-chip LTC6804 can measure the voltage of 3-12 series batteries (at least 3 pieces because of the need to provide a bias voltage of not less than llv). The stacked architecture can support hundreds of batteries and has a strong scalability. Buried Zener voltage reference with built-in third-order noise filtering incremental accumulation ADC. The cell voltage can be measured with 16-bit resolution and better than 0.04% accuracy. In the fast mode, all cells can be measured in 290us, with passive charge balancing. The LTC6820 provides isolated SPI communication between two isolated devices through a single 1 and twisted pair connection. The intermediate transmission is a two-wire isoSPI link, thus completing the standard four-wire SPI of the MCU to the isoSPI of the LTC6804. The link conversion link is in the form of an isolation transformer plus twisted pair, which can achieve good common mode rejection and voltage isolation. The isolation transformer of the isoSPI bus inter-chain is made of PULSE HX1188NL. Each one contains two isolation transformers and includes a center tap and a common mode choke. The NTC (negative temperature coefficient) thermistor bias circuit is combined with the LTC138 (X8 MUX) circuit to achieve multi-channel temperature monitoring with certain accuracy. The specific temperature measurement principle is that the thermistor is connected in series with a high precision standard resistor. The reference power supply provided by the LTC6804 is divided, the channel is selected through the MUX circuit, and the voltage is measured by the first-order proportional circuit, and then the corresponding channel is input for voltage measurement. Into the temperature. Breeze Pro Vape 2000Puffs,Breeze Pro Flavors Disposbale Vape,Breeze Pro 2000 Device Disposable,Breeze Vape Device Pro 2000 Shenzhen Zpal Technology Co.,Ltd , https://www.zpal-vape.com
1.1, introduction of LTC6804