SLUSC25A February 2015 – August 2017 TPS2388
PRODUCTION DATA.
The TPS2388 features ten multi-slope integrating converters. Each of the first eight converters is dedicated to current measurement for one port and is operated independently to perform measurements in any of the following modes: classification and port powered. When the port is powered, the converter is used for current (100-ms averaged) monitoring, port policing, and DC disconnect. Each of the last two converters are shared within a group of four ports for discovery (16.6-ms averaged), port powered voltage monitoring, Power Good status, and FET short detection. It is also used for general-purpose measurements including input voltage (1 ms) and temperature.
The A/D converter type used in the TPS2388 differs from other similar types of converters in that it converts while the input signal is being sampled by the integrator, providing inherent filtering over the conversion period. The typical conversion time of the current converters is 800 µs, while it is 1 ms for the other converters. Powered-device detection is performed by averaging 16 consecutive samples providing significant rejection of noise at 50-Hz or 60-Hz line frequency. While a port is powered, digital averaging is used to provide a port current measurement integrated over a 100-ms time period. Note also that an anti-aliasing filter is present for port powered current monitoring.
NOTE
During port-powered mode, port current conversions are performed continuously. Also, in port-powered mode, the tSTART timer must expire before any current or voltage A/D conversion can begin.