ISL78229 Datasheet, PDF (50/71 Pages) Intersil Corporation – 2-Phase Boost Controller with Drivers

ISL78229
OT_NTC_FAULT_LIMIT (4Fh)
Definition: Set/Read the voltage threshold for the external over-temperature fault (OT_NTC_FAULT). As described in “External
Temperature Monitoring and Protection (NTC Pin)” on page 38, the NTC pin voltage represents the temperature of the board (Figure 71 on
page 38). The ISL78229 compares the NTC pin voltage V_NTC to a voltage threshold which is set by this OT_NTC_FAULT_LIMIT command
to detect if OT_NTC_FAULT occurs.
The OT_NTC_FAULT_LIMIT command has two data bytes formatted as 16Lu (“Write/Read the 16Lu Data to Set NTC Threshold” on
page 42). Bits [15:10] are not used and Bits [9:0] unsigned binary integer value represents the voltage threshold for V_NTC with
2mV/LSB. The OT_NTC_FAULT_LIMIT has default setting of 0096h meaning 300mV threshold for V_NTC.
When V_NTC is lower than 300mV (default), the OT_NTC_FAULT event is triggered. For detailed descriptions of this fault, refer to “External
Over-Temperature Fault (OT_NTC_FAULT)” on page 39, Table 3 on page 41 and the “PMBus™ Command Summary” on page 43 to
deactivate this fault and configure the fault response.
To convert the voltage threshold to temperature threshold, refer to the specific V_NTC versus temperature characteristic curve (example
Figure 71 on page 38) for each specific application setup.
Data Length in Bytes: 2
Data Format: 16Lu
Type: R/W
Protectable: Yes
Default Value: 0096h. With 0096h = 150(decimal) and 2mV/LSB, the OT_NTC_FAULT default threshold for V_NTC is
150 * 2mV = 300mV.
Units: mV (referred for voltage threshold for V_NTC with 2mV/LSB)
Equation: V_{OT_NTC_FAULT_LIMIT} = 0.002 * OT_NTC_FAULT_LIMIT as Equation 23 on page 42, where OT_NTC_FAULT_LIMIT is the 16Lu
data in this command, and V_{OT_NTC_FAULT_LIMIT} refers to the OT_NTC_FAULT threshold for V_NTC
Range: 0 to 2.046V
COMMAND
Format
Bit Position
Access
Function
Default Value
OT_NTC_FAULT_LIMIT (4Fh)
16Lu
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W R/W
See Following Table
0000000010010110
BIT NUMBER
9:0
15:10
MEANING
Set/Read the voltage threshold for V_NTC as OT_NTC_FAULT fault detection with 2mV/LSB
Not used
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FN8656.3
February 12, 2016