ISL78610 Datasheet, PDF (76/98 Pages) Intersil Corporation – Multi-Cell Li-Ion Battery Manager

ISL78610
the fault by writing 14’h0000 to the Fault Status register, having
first cleared the bits in the Fault Data register(s) if these are set.
The device then responds ACK as with a normal write response
since the fault status bits are now cleared. This also prevents
further Fault responses unless the fault reappears, in which case
the Fault response is repeated.
Additionally, the fault status of each part may be obtained at any
time by reading the Fault Status register.
The FAULT logic output is asserted in Sleep mode, if a fault has
been detected and has not been cleared.
FAULT RESPONSE IN SLEEP MODE
When a stand-alone device is in the Sleep mode, the device may
still detect faults if operating in Scan Continuous mode. If an
error occurs, the FAULT output pin is asserted low.
Devices may detect faults if operating in Scan Continuous mode
while also in Sleep mode.
Daisy chain devices registering a fault in Sleep mode proceed to
wake up the other devices in the stack (e.g., middle devices send
the Wake-up signal on both ports). Any communications received
by a device on one port while it is transmitting the Wake-up
signal on its other port are ignored. After receiving the Wake-up
signal, the top stack device waits before sending an ACK
response on Port 1. This is to allow other stack devices to wake
up. The total wait time is dependent on the number of devices in
the stack. The time from a device detecting a fault to receipt of
the ACK response is also dependent on the stack position of the
device. See Table 14 for maximum response times for stacks of
8 and 14 devices.
The normal host microcontroller response to receiving an ACK
while the stack is in Sleep mode is to read the Fault Status
register contents of each device in the stack to determine which
device (or devices) has a fault.
Fault Diagnostics
Table 47 shows a summary of commands and responses for the
various fault diagnostics functions.
TABLE 47. SUMMARY OF FAULT DIAGNOSTICS COMMANDS AND RESPONSES
DIAGNOSTIC
ITEM FUNCTION
ACTION REQUIRED
REGISTER READ/WRITE
COMMENTS
1 Static fault
detection
functions.
Check Fault Status (or look Read Fault Status register The main internal functions of the ISL78610 are monitored
for normal fault response)
continuously. Bits are set in the Fault Status register is response to
faults being detected in these functions.
2 Oscillator check Check for device in Sleep
function
mode if stack returns a
Communications Failure
response.
Oscillator faults are detected as part of the Static Fault detection
functions. The response to an oscillator fault detection is to set the OSC
bit in the Fault Status register and then to enter Sleep mode. A sleeping
device does not respond to normal communications, producing a
Communications Failure notification from the next device down the
stack. The normal recovery procedure is send repeated Sleep and
Wake-up commands ensure all devices are awake.
3 Cell overvoltage Set cell overvoltage limit
Write Overvoltage Limit Full scale value 14'h1FFF = 5V
register
4
Set fault filter sample value Write TOT bits in Fault Default is 3'b011 (8 samples) - (see “Fault Setup:” on page 85)
Setup register
5
Identify which inputs have Write Cell Setup register A '0' bit value indicates cell is connected. A '1' bit value indicates no cell
cells connected
connected to this input. The overvoltage test is not applied to
unconnected cells.
6
Scan cell voltages
Send Scan Voltages
A cell overvoltage condition is flagged after a number of sequential
command
overvoltage conditions are recorded for a single cell. The number is
programmed above in item 4.
7
Check fault status
Read Fault Status register The device sends the Fault Status register contents automatically if a
fault is detected, if the register value is zero before the fault is detected.
8
Check overvoltage fault Read Overvoltage Fault Only required if the Fault Status register returns a fault condition.
register
register
9
Reset fault bits
Reset bits in Overvoltage Fault register followed and bits in Fault Status
register.
10
Reset fault filter
Change the value of the [TOT2:0] bits in the Fault Setup register and
then change back to the required value. This resets the filter. The filter
is also reset if a false overvoltage test is encountered.
11 Cell
Set cell undervoltage limit Write Undervoltage Limit Full scale value 14'h1FFF = 5V
Undervoltage
register
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June 16, 2016