4Component description
4.1 STPM33
The STPM33 belongs to a mixed signal IC family designed for high accuracy measurement of power and
energies in power line systems using the Rogowski coil, current transformer or shunt current sensors.
The STPM3x provides instantaneous voltage and current waveforms. It also calculates RMS values of voltage
and currents, active, reactive and apparent power and energies.
The analog section consists of up to two programmable gain low-noise low-offset amplifiers and up to four second
order 24-bit sigma-delta ADCs, two band gap voltage references with independent temperature compensation, a
low drop voltage regulator and DC buffers.
The digital section consists of digital filtering stage, a hardwired DSP, DFE to the input and a serial communication
interface (UART or SPI).
The STPM3x is fully configurable and allows a fast digital system calibration in a single point over the entire
current dynamic range.
4.2 STM32L433VCT6
The STM32L433VCT6 is an ultra-low-power microcontroller based on the high-performance Arm® Cortex®-M4
32-bit RISC core operating at a frequency of up to 80 MHz. The Arm® Cortex®-M4 core features a floating-point
unit (FPU) single precision which supports all Arm® single-precision data processing instructions and data types.
It also implements a full set of DSP instructions and a memory protection unit (MPU) which enhances application
security.
The STM32L433xx devices embed high-speed memories (Flash memory up to 256 Kbyte, 64 Kbyte of SRAM),
a quad SPI Flash memory interface (available on all packages) and an extensive range of enhanced I/Os and
peripherals connected to two APB buses, two AHB buses and a 32-bit multi-AHB bus matrix.
The STM32L433xx devices embed several protection mechanisms for embedded Flash memory and SRAM:
readout protection, write protection, proprietary code readout protection and firewall.
The devices offer a fast 12-bit ADC (5 Msps), two comparators, one operational amplifier, two DAC channels,
an internal voltage reference buffer, a low-power RTC, one general-purpose 32-bit timer, one 16-bit PWM timer
dedicated to motor control, four general-purpose 16-bit timers, and two 16-bit low-power timers.
In addition, up to 21 capacitive sensing channels are available. The devices also embed an integrated LCD driver
8x40 or 4x44, with internal step-up converter.
They also feature standard and advanced communication interfaces.
Some independent power supplies are supported: analog independent supply input for ADC, DAC, OPAMP and
comparators, and 3.3 V dedicated supply input for USB. A VBAT input allows to back up the RTC and registers.
Dedicated VDD12 power supplies can be used to bypass the internal LDO regulator when connected to an
external SMPS.
4.3 ALTAIR04-900
The ALTAIR04-900 is a high voltage all-primary-sensing switcher, operating directly from the rectified mains with
minimum additional external parts. It combines a high performance low voltage PWM controller chip and a 900 V
avalanche-rugged power section in the same package.
The controller is in current mode specifically designed for off-line quasi-resonant flyback converters.
The device provides a constant output voltage using the primary-sensing feedback, eliminating the need of an
optocoupler, a secondary voltage reference, and a current sensor, but still maintaining an accurate regulation.
The maximum deliverable output current can be set to increase the end-product safety and reliability in case of
fault events.
Quasi-resonant operation is guaranteed by a transformer demagnetization sensing input which turns on the power
section. The same input also serves the output voltage monitoring, to perform CV regulation, and to achieve
mains-independent maximum deliverable output current (line voltage feed-forward).
The maximum switching frequency is 166 kHz: at light-to-medium load, a special function automatically lowers
the operating frequency maintaining the valley switching operation. When the load is very light, the device enters
a controlled burst mode operation that, along with the built-in high voltage startup circuit and the low operating
current, minimizes the standby power.
UM2898
Component description
UM2898 - Rev 1 page 7/31
