TPS65400_15 Datasheet, PDF (31/76 Pages) Texas Instruments – TPS65400 4.5- to 18-V Input Flexible Power Management Unit With PMBus/I2C Interface

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t_TIMEOUT:SCL
t_TIMEOUT:SDA
TPS65400
SLVSCQ9B – NOVEMBER 2014 – REVISED SEPTEMBER 2015
Table 5. Timeout Specifications
PARAMETER
MIN
Detect clock low timeout
25
Detect data low timeout
25
MAX
35
35
UNIT
ms
ms
8.5.1.2.7 CONTROL Terminal
The TPS65400 enable terminals ENSWx are equivalent to the CONTROL terminals in the fault handling. The
enable terminals behave as follows:
• Unit does not power up until commanded by the enable terminal and OPERATION command. By default, the
OPERATION command is ON, so the powering up of the unit depends on the enable terminal state.
• To start, the unit requires that the on/off portion of the OPERATION command is instructing the unit to run.
Depending on PIN_CONFIG_00, the unit may also require the enable terminal to be asserted for the unit to
start and energize the output.
• Polarity of the enable terminal is active high. If unconnected, the terminal goes high.
• When commanding the unit to turn on or off through the enable terminals, the programmed turn on delays,
turn off delays are always observed.
There are differences in enable terminal functionality depending on terminal configuration PIN_CONFIG_00. For
more information, refer to OPERATION and PIN_CONFIG_00.
8.5.1.2.8 Packet Error Checking
The TPS65400 supports an optional PEC code to be validated at the end of every write and to be appended to
the end of every read. TI highly recommends it, but it is not required.
8.5.1.2.9 Group Commands
Fully-compliant group commands are supported.
8.5.1.2.10 Unsupported Features
All undocumented, optional features are not supported. Extended commands are not supported.
8.5.2 PMBus Register Descriptions
The PMBus specification referenced by this section is PMBus Power System Management Protocol Specification
Part II – Command Language, Revision 1.2, dated 6 September 2010. The specification is published by the
Power Management Bus Implementers Forum and is available from http://pmbus.org/specifications.
8.5.2.1 Overview
The following parameters can be programmed and read. These are individually available for each power supply
output (SW1-SW4):
• Voltage reference
• Start sequencing
• Stop sequencing
• Switching frequency
• Switching phase
• Soft-start time
• Current limit
• Current sharing operation with SW1-SW2 and/or SW3-SW4 pairs
• Power Good
• Fault status
Each power supply has its own set of PMBus commands. Paging is supported to allow device selection for a
PMBus session ((00h) PAGE). Table 6 lists supported PMBus commands and paging values.
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