ISL78610 Datasheet, PDF (41/98 Pages) Intersil Corporation – Multi-Cell Li-Ion Battery Manager

ISL78610
Scan Voltages Command
When a device receives the Scan Voltages command to its stack
address (or an Address All stack address), it increments the scan
counter (see “Scan Counter” on page 43) and begins a scan of
the cell voltage inputs. It sequences through the cell voltage
inputs in order from cell 12 (top) to cell 1 (bottom). This operation
is followed by a scan of the Pack Voltage.
The scan operation forces a sample and hold on each input, an
analog-to-digital conversion of the voltage, and the storage of the
value in its appropriate register. The IC temperature is also
recorded for use with the internal calibration routines.
The Scan Voltages command performs cell overvoltage and
undervoltage comparisons on each cell input and checks the
VBAT and VSS connections for open-wire at the end of the scan. If
there is a fault condition (see “Fault Diagnostics” on page 76 for
what constitutes a fault condition), the device sets the specific
fault bit, sets the device FAULT pin active and sends an
“unprompted fault response” to the host down the daisy chain
communication link. (A stand-alone device only sets the FAULT
pin.) The Unprompted Response is identical to a “Read Status
Register” command.
Devices revert to the Standby state on completion of the scan
activity.
Cell voltage and Pack voltage data, along with any fault
conditions are stored in local memory ready for reading by the
system host microcontroller.
Scan Temperatures Command
When a device receives the Scan Temperatures command to its
stack address (or an Address All stack address), it increments
the scan counter (see “Scan Counter” on page 43) and begins a
scan of the temperature inputs.
The Scan Temperatures command causes the addressed device
(or all devices with an Address All stack address) to scan through
the internal and 4 external temperature signals followed by
multiplexer loopback and reference measurements. The
loopback and reference measurements are part of the internal
diagnostics function. Over-temperature compares are performed
on each temperature measurement depending on the condition
of the appropriate bit in the Fault Setup register.
Temperature data, along with any fault conditions, are stored in
local memory ready for reading by the system host
microcontroller. If there is a fault condition, the device sets its
FAULT pin active and on completion of a scan sends an
“unprompted fault response” to the host down the daisy chain
communication link. (A stand-alone device only sets the FAULT
pin.) The Unprompted Response is identical to a “Read Status
Register” command.
Devices revert to the Standby state on completion of the scan
activity.
See also “Temperature Monitoring Operation” on page 43.
Scan Mixed Command
When a device receives the Scan Mixed command to its stack
address (or an Address All stack address), it increments the Scan
counter (see “Scan Counter” on page 43) and begins a Scan
Mixed operation.
The Scan Mixed command causes the addressed device (or all
devices with an Address All stack address) to scan through the
cell voltage inputs in order from cell 12 (top) to cell 7. Then the
external input ExT1 is measured, followed by a scan of cell 6 to
cell 1. These operations are followed by a scan of the Pack
Voltage and the IC temperature. The IC temperature is recorded
for use with the internal calibration routines.
Scan Mixed also performs cell overvoltage and undervoltage
comparisons on each cell voltage sampled. The VBAT and VSS
pins are also checked for open conditions at the end of the scan.
ExT1 is sampled in the middle of the cell voltage scan such that
half the cells are sampled before ExT1 and half after ExT1. This
mode allows ExT1 to be used for an external voltage
measurement, such as a current sensing, so it is performed
along with the cell voltage measurements, reducing the latency
between measurements.
The Scan Mixed command is intended for use in stand-alone
systems, or by the master device in stacked applications, and
would typically measure a single system parameter, such as
battery current or Pack voltage.
Cell voltage, Pack voltage and ExT1 data, along with any fault
conditions are stored in local memory ready for reading by the
system host microcontroller. Access the data from the ExT1
measurement by a direct Read ET1 Voltage command or by the All
Temperatures read command.
If there is a fault condition, (see “Fault Diagnostics” on page 76
for what constitutes a fault condition), the device sets the FAULT
pin active and on completion of a scan sends an “unprompted
fault response” to the host down the daisy chain communication
link. (A stand-alone device only sets the FAULT pin.) The
unprompted response is identical to a “Read Status Register”
command.
Devices revert to the Standby state on completion of the scan
activity.
Scan Wires Command
When a device receives the Scan Wires command to its stack
address (or an Address All stack address), it increments the Scan
counter (see “Scan Counter” on page 43) and begins a Scan
Wires operation.
The Scan Wires command causes the addressed device (or all
devices with an Address All stack address) to measure all the
VCn pin voltages while applying load currents to each input pin in
turn. This is part of the fault detection system.
If there is a fault condition, the device sets the FAULT pin and
returns a fault signal (sent down the stack) on completion of a
scan.
No cell voltage data is sent as a result of the Scan Wires
command. Devices revert to the standby state on completion of
this activity.
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June 16, 2016