RAA489204 for long strings
- Stackable up to 30 ICs
- Up to 14-cells monitored (10 to 65V)
- ±10mV accuracy, ±190mV pack accuracy
- Measures and sends voltages, temperatures and diagnostics for 112 cells in <10ms
- Supports CoO2 Mn2O4 and FePO4 Li-ion chemistries
- Daisy chain typically draws 1mA when transmitting 10% of time
- Internal (10mA) and external passive cell balancing
- 64pad TQFP
The RAA489204’s two-wire bi-directional daisy chain is ac-coupled, dc-balanced and fully differential for maximum EMI immunity. One of three operating rates can be selected: 333kHz, 500kHz or 1MHz. Not shown in the diagram are passive components including the common-mode choke needed in some applications.
It can be used on-board or, with an un-screened twisted-pair cable (and safety components), off-board at up to 500mm range. It is not recommended for use across the systems low-voltage to high-voltage barrier, but it can be transformer-coupled to allow this – transformer coupling also removes the cable capacitance restriction, allowing connection over many metres.
CRC (cyclic reduncancy checking) ins included in the daisy-chain protocol to verify integrity for the header packet and data packets.
An 2.5Mbit/s SPI bus is provided so that the bottom IC in a string can communicate with the host microcontroller.
RAA489206 for 4S to 16S
- Up to 16 cells handled (12 to 55V)
- ±10mV accuracy
- Low-side current sense
- High-side charge/discharge protection
- Internal (8mA) and external (200mA) passive cell balancing
- 62V hot plugging
- 64pad QFN
The 16 cell RAA489206 operates with a pair of external mosfets for pack protection and one mosfet per cell if external balancing is needed. An external npn Transistor is used with on-chip circuitry to establish the internal logic supply – the RAA489204 also uses this technique.
Communication with its host over I2C, SPI (with or without CRC).
Consumption is 200µA idling or 18µA in shipping mode.
Renesas sees both poducts being of intertest to designers of e-scooters and high-voltage power tools, and “the increasing adoption of battery management systems in the un-interruptable power supplies of the data center is spiking demand for ICs that can support higher voltage and larger cell battery pack sizes”, according to Renesas power division v-p Andrew Cowell.
Grid backup is another potential application for the daisy-chained RAA489204.
Product pages
RAA489204
RAA489206