Temperature Sensor - STMicroelectronics SPC572L series Reference Manual

Temperature Sensor

38 Temperature Sensor
38.1 Introduction
The device includes two on-chip temperature sensors that monitor device temperature and
delivers one analog output signal and three digital output signals each. The analog output
consists of a voltage signal directly proportional to the internal junction temperature. The
analog output is connected to an input channel of an ADC on the device. The internal
junction temperature must be calculated by software based on the sampled temperature
sensor voltage, sampled reference voltage, which comes from another module, and
calibration parameter values stored in internal flash memory. The three digital outputs,
connected to the PMC module, are used to signal under- and overtemperature operating
conditions. The digital outputs signal when the junction temperature drifts below the low
temperature threshold or above one of two high temperature thresholds. These signals
notify the device to take action to appropriately adjust the device temperature in response to
an out of specification low or high temperature operating condition. Calibration parameter
values associated with the temperature threshold detection feature are determined and
stored in internal flash memory during production testing at the factory.
38.1.1 Signal Descriptions
This module has no external signals.
38.2 Functional Description
The temperature sensor generates one analog output voltage, VTSENS(T), which is
proportional to the absolute current junction temperature of the device, and three digital
outputs that signal whether the junction temperature has reached either a pre-set low
temperature threshold or one of two pre-set high temperature thresholds.
An on-chip ADC module is used to convert the analog output voltage, as well as the
bandgap voltage, into a digital representation. These values, along with parameter values
stored in on-chip flash memory, are used by software to calculate the device junction
temperature.
38.2.1 Temperature threshold detection (digital output generation)
Temperature threshold trimming values are adjusted through calibration during factory test
and stored in on-chip flash memory. While enabled, if a new trimming value is loaded into
the Temperature Sensor module, it may take up to 1 ms for the digital outputs to be updated
to reflect the new trimming condition.
842/2058 DocID027809 Rev 4
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