Ricoh Europe (Netherlands) B.V. Semiconductor Support Centre has launched a new Analog Front-End (AFE) Integrated Circuit (IC), the R5601. The new addition to Ricoh’s battery management ICs portfolio is designed for Lithium-ion or Lithium-polymer battery packs of three up to five cells in series. Applications include cordless power tools, robot vacuum cleaners, lawn mowers, and electrical bikes.
Traditional stand-alone protection ICs have internally fixed hardware settings for various monitoring thresholds that decide to interrupt the charge or discharge process and control the external dual MOSFET. The advantage of an AFE IC versus a stand-alone protection IC is the flexible concept enabling short time to the market. An AFE IC is a measurement device of which the results are forwarded to a MCU (microcontroller unit). The fact that all threshold settings are saved within the software of the MCU and software settings are easily adaptable means a significant advantage. Therefore, an AFE IC is more convenient to use as a standard measurement IC for various battery pack designs.
The R5601 AFE IC and MCU are able to communicate through a 2 wire I2C interface. The designer can control or monitor various functions by software and select from three operating modes:
- Normal operation mode: all IC functions are operational, 36µA supply current
- Low consumption mode: some internal functions disabled to achieve 6.5µA supply current
- Standby mode: operation mode with 2.5µA supply current
The wake up function assures that the R5601 starts operating from a low power mode in the normal operation mode when load current is detected.
Each individual cell voltage as well as the pack current can be measured. The analog results are amplified and forwarded through the voltage monitoring and current monitoring output pin. The MCU is able to measure the cell voltage and current by using an external analog to digital converter (ADC). The R5601 provides the required high accurate reference voltage for the ADC circuit. An internal voltage regulator is embedded to provide a supply voltage to the MCU.
The Alert output provides a notification to the microcontroller when detecting a fault event. The software can obtain a more detailed description of this fault event from the internal registers.
Embedded MOSFET switches take care of cell balancing, making sure that each cell has an equal voltage level. If needed, the charge or discharge process will be interrupted to initiate the cell balancing process and resumes automatically the previous process when completed.
As an additional safety protection, an internal thermal shutdown circuit is integrated within the IC to detect a thermal overload.
The R5601 is available in a TSSOP-16 package.
High-voltage Process Absolute Maximum Rating: 32V
Current Consumption Normal Mode: Typ. 36μA
Low Power Mode (Only VR and wakeup function operating): Typ. 6.5μA
Standby Mode: Max. 2.0μA
High-accuracy Voltage Monitor Gain: 0.6 Input-referred Voltage Error: ±9mV
Output-referred Voltage Error: ±5.4mV
High-accuracy Current Monitor: R5601TxxxAA Gain: 10 ±1.0%, 40 ±2.0%
R5601TxxxAC Gain: 5 ±0.8%, 10 ±1.0%
Short-circuit Current Detection: Detector threshold and delay time settings by I2C interface
Detector Threshold: 0.10, 0.15, 0.20, 0.40V
Delay Time: 50, 100, 200, 400, 800μs
External Reference Voltage Output 3.0000V ±3.5mV
Temperature Characteristics: ±30ppm/°C (0 ≤ Ta ≤ 50°C, Ta ≈ Tj)
Voltage Regulator Output Voltage: 3.3V
Output Voltage Accuracy: 1.5% (−20°C to 60°C)
Output Current Limit: Min. 30mA
Thermal Shutdown: enabled / disabled by I2C interface
Built-in FET Switch: FET Switch can be set with MCU using I2C interface
Alert Output: event notification output to MCU
Low-Power Mode: some internal circuits disabled by MCU control
Standby Mode: sets the IC to standby mode to reduce the consumption current
Wake-up Function: wakes the IC to normal mode when detecting a discharging current
I2C Interface: Communication interface with MCU
Package: TSSOP-16 (0.65 mm pitch)
More information + Datasheet: http://www.e-devices.ricoh.co.jp/en/products/product_power/bmu/r5601/
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