STPMC1 ST Microelectronics, STPMC1 Datasheet - Page 19

• Manufacturer Part Number: STPMC1
• Description: Programmable poly-phase energy calculator IC
• Manufacturer: ST Microelectronics

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STPMC1
9
9.1
Table 9.
Channel name
Theory of operation
General operation
The STPMC1 (also called a calculator) is an ASSP designed for effective measurement in
power line systems utilizing the Rogowski coil, current transformer, Shunt or Hall current
sensors. This device, used with the STMicroelectronics STPMSx companion chip (an
analog front-end device), can be implemented as standalone or as a peripheral in a
microprocessor based 1-, 2- or 3-phase energy meter.
The calculator consists of three sections: analog, digital and OTP (see
●
●
●
The calculator has five input data pins, of which four are fed by signals generated by the
STPMSx, see
Three of them (DAR/DAS/DAT) are used to receive multiplexed signals of voltage and
current, implementing energy measurement in 1-, 2- and 3-phase (3 and 4 wires) systems.
After being de-multiplexed, each phase input is sent to the correspondent DSP unit that
processes voltage and current information and performs energy calculation, according to
the settings of the configuration bits (see
The DAN input, which also receives a multiplexed signal output from STPMSx device, is
typically used to monitor neutral current for anti tampering functions in 1-, 2- and 3-phase (4
wires) systems. Normally the STPMSx monitors current and voltage but in case of neutral
monitoring the voltage channel can be connected to a different type of sensor, for example a
temperature sensor.
The fifth input data pin (DAH) accepts non-multiplexed
sensing through Hall sensors or for temperature sensing.
Input channels from the STPMSx
The companion chip (STPMSx) embeds 2
capable of providing the multiplexed
See the STPMSx documentation for more details.
DAR
DAS
DAN
DAH
DAT
The analog section is composed of a band-gap voltage reference and a low-drop
voltage regulator.
The digital section consists of a system control, clock generator, three PDSP and a
NDSP, a SPI interface.
The 112-bit OTP block and the 16 system signals, used for testing, configuration and
calibration purposes, are controlled through SPI by means of a dedicated command
set.
Table
9.
Not multiplexed
Multiplexed
Multiplexed
Multiplexed
Multiplexed
Property
Doc ID 15728 Rev 1
streams.
Table
ADC converters and the necessary logic
31).
Temperature
Signal 1
Voltage
Voltage
Voltage
signals. It can be used for EMI
EMI or temperature
Theory of operation
Figure
Signal 2
Current
Current
Current
Current
1):
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