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STM32F334: the new STM32 Digital-Power Microcontroller

Question asked by Amel N Employee on Jun 25, 2014

ST’s new microcontroller STM32F334 simplifies transition to energy-efficient digital power supplies by providing all the major power-control functions in a single chip.

The STM32F334 microcontrollers have ample computation capabilities thanks to the 72MHz ARM® Cortex®-M4 core with DSP and floating-point unit (FPU).
The on-board Core-Coupled Memory (CCM-SRAM) provides a “routine boost” (90DMIPS equivalent to >100MHz CPU frequency), which accelerates the execution of control loop or any critical routine.

The high-resolution timer is based on a modular architecture providing 217 ps resolution, guaranteed over voltage and temperature changes, and offers over 10 independent PWM outputs to control converters with a large number of switches or multiple converters in parallel.
The guaranteed resolution of 217ps allows fine control of resonant soft-switching converters, which are becoming more widely used.
For such LLC converters, the high resolution allows finer frequency and phase adjustments for improved voltage regulation and transient management.
Controlling the 10 timer outputs is simple and flexible thanks to the internal crossbar. PWMs are optimized for control of power switches,  with built-in shut-down capability, dead-time control, synchronization support, and safety features. The transparent high-resolution implementation simplifies programming: the timer is programmed similarly to a standard timer clocked at 4.6GHz.
A ‘Cook Book’ (AN4539) helps users operate the high-resolution timer in various basic power-supply topologies.

Beside this high-resolution timer, the STM32F334’s peripheral set optimized for digital power control includes:

  • 2 ultra-fast 5Msps (0.2µs) 12-bit ADCs with sampling time down to 21ns for simultaneous voltage and current measurements
  • 3 ultra-fast comparators with 25ns response time from analog input to PWM output, which helps ensure safe power-supply operation
  • 3 DACs  and one operational amplifier with built-in gains 
  • CAN, I²C (PMBus/SMBus)

The devices are fully supported by the latest version of STM32Cube software.

The boards related to the STM32F334 ecosystem and available now are:

  • Discovery kit (32F3348DISCOVERY) with on-board buck-boost converter
  • 500W Digital Switched-Mode Power Supply (DSMPS) evaluation board (STEVAL-ISA147V2) featuring a resonant LLC DC/DC converter and semi-bridgeless Power-Factor Correction (PFC)
  • The STM32Nucleo open platform (NUCLEO-F334R8)

STM32F334  Press Release