Voltage Operating Range; Linear Regulators - STMicroelectronics AEK-POW-BMS63EN User Manual

The L9963E main activity consists of monitoring cells and battery pack status through stack voltage
measurement, cell voltage measurement, temperature measurement, and coulomb counting. Measurement and
diagnostic tasks can be executed either on demand or periodically, with a programmable cycle interval.
Measurement data is available for an external microcontroller to perform charge balancing and to compute the
state of health (SOH) and state of charge (SOC).
The IC works in normal mode performing measurement conversions, diagnostics, and communication. The device
can also be put into a cyclic wakeup state in order to reduce the current consumption from the battery.
Passive cell balancing can be performed either via internal discharge path or via external MOSFETs. The
controller can either manually control the balancing drivers or start a balancing task with a fixed duration. In
the second case, the balancing may be programmed to continue also when the IC enters a low power mode
called silent balancing, to avoid unnecessary current absorption from the battery pack.
Thanks to the GPIOs, the device also offers the possibility to operate a distributed cell temperature sensing via
external NTCs resistances.
The external microcontroller can communicate with L9963E via SPI protocol. The physical layer can either be a
classic 4-wire based SPI or 2-wire transformer/capacitive based isolated interface through a dedicated isolated
transceiver device.
The L9963E performs automatic validation of any failure involving the cells or the whole battery pack. The device
can detect the loss of the connection to a cell or GPIO terminal. Moreover, it features a hardware self-check
(HWSC) that verifies the correct functionality of the internal analog comparators and the ADCs. All these checks
are automatically performed in case a failure involving both cells or when the battery pack is detected. The
current sensing interface used for coulomb counting is also capable of detecting failures such as open wires and
overcurrent in sleep mode. The cell balancing terminals can detect any short/open fault and the internal power
MOS are protected against overcurrent.
1.3

Voltage operating range

The AEK-POW-BMS63EN maximum voltage range for each cell is 4.2 V.
The power supply range is from 9.6 V to a maximum of 64 V.
1.3.1

Linear regulators

The AEK-POW-BMS63EN features several linear voltage regulators, which are switched on according to a
specific sequence at power-up (see
VREG
This linear regulator exploits an external MOS to decrease the power dissipation inside the L9963E.
It acts as a pre-regulator, supplying all other internal regulators (VANA, VCOM, VTREF, and VDIG). It is switched
off in low power modes (sleep, silent balancing, off phase of the cyclic wakeup).
VANA
This low drop regulator supplies all the ADC, comparators, monitors, main bandgap, current generator, and other
analogic blocks.
VCOM
The isolated communication receiver/transmitter and the GPIO output buffers are supplied by this low drop
regulator.
VTREF
This low drop regulator is used to supply external components such as NTCs for temperature sensing.
The recommended application circuit in NTC analog front end guarantees that each NTC channel sinks no more
than 500 µA.
VTREF regulator is disabled by default. Its operation can be controlled via SPI.
In absolute measurements, there is no reference value, while the ratiometric measurement is based on reference
value defined by the VTREF regulator. If the VTREF goes low in case of an error, the VTREF varies to
compensate this error.
All of the above regulators have dedicated UV/OV diagnostics.
UM3185 - Rev 1
Figure 11. Finite state machine of the voltage conversion
UM3185
Voltage operating range
routine).
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