Datasheet

Exponent
OUT(oc)
Mantissa
I Mantissa 2
2
= ´ =
TPS40400
www.ti.com SLUS930B –APRIL 2011– REVISED OCTOBER 2011
01: The device continues operation for four switching cycles. If the fault is still present, the device shuts
down and responds according to RS[2:0].
10: The device shuts down and responds according to RS[2:0].
11: The device shuts down and attempts to restart.
RS[2:0]
Output voltage undervoltage retry setting
000: A zero value for the Retry Setting means that the unit does not attempt to restart. The output
remains disabled until the fault is cleared (See section 10.7 of the PMBus spec.)
111: A one value for the Retry Setting means that the unit goes through a normal startup (Soft start)
continuously, without limitation, until it is commanded off or bias power is removed or another fault
condition causes the unit to shutdown.
Any value other than 000 or 111 is not accepted.
IOUT_OC_FAULT_LIMIT (46h)
The IOUT_OC_FAULT_LIMIT command sets the value of the output current, in amperes, that causes the
over-current detector to indicate an over-current fault condition. The IOUT_OC_FAULT_LIMIT should be set to
equal to or greater than the IOUT_OC_WARN_LIMIT. Writing a value to IOUT_OC_FAULT_LIMIT less than
IOUT_OC_WARN_LIMIT causea the device to set the CML bit in the STATUS_BYTE and the invalid data (ivd)
bit in the STATUS_CML registers as well as assert the SMBALRT signal. The contents of this register can be
stored to non-volatile memory using the STORE_DEFAULT_ALL or STORE_DEFAULT_CODE commands.
The IOUT_OC_FAULT_LIMIT takes a two-byte data word formatted as follows:
Command IOUT_OC_FAULT_LIMIT
Format Linear, two's complement binary
Bit Position 7 6 5 4 3 2 1 0 7 6 5 4 3 2 1 0
Access r r r r r r r r r r r/w r/w r/w r/w r/w r/w
Function Exponent Mantissa
Default Value 1 1 1 1 1 0 0 0 0 0 0 1 0 1 0 0
Exponent
–1 (dec), fixed.
Mantissa
The upper five bits are fixed at 0.
The lower six bits are programmable with a default value of 20 (dec)
The actual output current for a give mantissa and exponent is shown in Equation 21.
(21)
The default output fault current setting is 10 A. Values of I
OUT(oc)
can range between 0 A and 35 A in 500-mA
increments.
IOUT_OC_FAULT_RESPONSE (47h)
The IOUT_OC_FAULT_RESPONSE command instructs the device on what action to take in response to an
IOUT_OC_FAULT_LIMIT fault. The device also:
• Sets the IOUT_OC bit in the STATUS_BYTE
• Sets the IOUT/POUT bit in the STATUS_WORD
• Sets the IOUT OC Fault bit in the STATUS_IOUT register, and
• Notifies the host as described in section 10.2.2 of the PMBus Specification.
Copyright © 2011, Texas Instruments Incorporated Submit Documentation Feedback 35
Product Folder Link(s) :TPS40400