STPM14

概要

The STPM1x family is designed for effective measurement of active energy in a power line system using a Rogowski Coil, current transformer and shunt sensors. This device is specifically designed to provide all the necessary features to implement a single phase energy meter without any other active component. The STPM1x device family consists, essentially, of two parts: the analog part and the digital part. The former, is composed of a preamplifier and first order ∑ Δ A/D converter blocks, band gap voltage reference, low drop voltage regulator. The digital part is composed of a system control, oscillator, hard wired DSP and interface for calibration and configuration. The calibration and configuration are done by OTP cells, that can be programmed through a serial interface. The configured bits are used for testing, configuration and calibration purposes. From two ∑ Δ output signals coming from the analog section, a DSP unit computes the amount of consumed active energy. The active energy is available as a pulse frequency output and directly driven by a stepper counter. In the STPM1x an output signal with pulse frequency proportional to energy is generated. This signal is used in the calibration phase of the energy meter application allowing a very easy approach. When the device is fully configured and calibrated, a dedicated bit of OTP block can be written permanently in order to prevent accidental entry into test mode or changing any configuration bit.