PI3749-00-EVAL1 Datasheet, PDF (21/26 Pages) Vicor Corporation – Cool-Power® ZVS Switching Regulators

PI3749-x0
I²C™ Parameter Readback
Fault Monitoring
Register
Name
Register
Address
Bit <7>
Bit <6>
FLT2
2
TRISE
OTP
FLT3
3
0
0
FLTREG_CLR
4
Table 4 — PI3749-20 Fault Readback/Clear Registers
Bit <5>
VOUT_NEG
0
Bit <4>
Bit <3>
VOUT_OV
EAIN_HI
0
Q1_FIL
Write only, data ignored
Bit <2>
VIN_OV
Q3_SIL
Bit <1>
VIN_UV
Q3_FIL
Bit <0>
VCC_UV
SLOW_IL
The fault bits in the FLT2 and FLT3 registers are only latched when the regulator first stops operating due to a given fault type. If the
regulator is already not operating (perhaps due to a fault protection or being disabled) then should a new fault condition occur, the fault bit
associated with the new fault will not be registered.
Both versions of the PI3749-x0 will auto recover from any fault protection mechanism, once the fault is corrected. However in order to aid in
monitoring of the regulator via the I²C fault monitoring registers, when a fault occurs, the associated fault bit(s) will set and latch until they
are explicitly cleared by the I²C host using the FLTREG_CLR register.
A write to the FLTREG_CLR register address will clear all latched fault register bits.
Fault Bit
Name
TRISE
Fault Bit
Location
FLT2, Bit<7>
Fault Destination
Overtemperature Protection: The predicted maximum hot-spot temperature, based on measured temperature and loading,
exceeded the maximum safe operating temperature.
OTP
FLT2, Bit<6> Overtemperature Protection: The internal measured temperature exceeded the maximum safe operating temperature.
VOUT_NEG
VOUT_OV
FLT2, Bit<5> V_OUT negative fault. The output voltage was below ground.
FLT2, Bit<4> Output Overvoltage protection.
EAIN_HI FLT2, Bit<3> Current Limit: Overload Timeout.
VIN_OV FLT2, Bit<2> Input Overvoltage Lockout.
VIN_UV FLT2, Bit<1> Input Undervoltage Lockout.
VCC_UV
Q1_FIL
FLT2, Bit<0>
FLT3, Bit<3>
V_CC undervoltage. The internal bias supply faulted due to undervoltage.
Current Limit: Fast current limit (Q1) The peak current through Q1 and the inductor was higher than
the maximum current allowed.
Q3_SIL
Q3_FIL
SLOW_IL
FLT3, Bit<2> Current Limit: Slow current limit (Q3)
FLT3, Bit<1>
Current Limit: Fast current limit (Q3) The peak current through Q3 and the inductor was higher than
the maximum current allowed.
FLT3, Bit<0> Current Limit: Slow current limit.
Table 5 — Fault register bit summary
I²C Volatile Addresses for Parameter Programming
Register
Name
Register
Address
Readback
capable?
Bit <3>
Bit <2>
MRGN
5
Yes
MRGN_ENA MRGN<2>
Table 6 — PI3749-20 Parameter Programming Volatile Registers
Bit <1>
MRGN<1>
Bit <0>
MRGN<0>
Cool-Power^® ZVS Switching Regulators
Page 21 of 26
Rev 1.8
03/2017
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