STM32G4/H7 Digital Power Application Sharing

STM32 Product Matrix for Digital Power Applications

STMicroelectronics offers a comprehensive range of STM32 microcontrollers tailored for energy and industrial applications, categorized by core type and performance:

• MPUs: STM32MP1
• High-Performance MCUs: STM32F2, STM32F4, STM32F7, STM32H7 series, featuring Arm Cortex-M7 cores up to 550 MHz and dual-core configurations.
• Mainstream MCUs: STM32F0, STM32G0, STM32F1, STM32F3, STM32G4, STM32L4, STM32L4+ series, based on Arm Cortex-M0, M0+, M3, M4, M33 cores, operating at frequencies up to 170 MHz.
• Ultra-Low-Power MCUs: STM32L0, STM32L1, STM32L5, STM32WL, STM32WB series, designed for efficiency.

The HRTIMER peripheral is specifically highlighted as being specialized for digital power applications. STMicroelectronics also emphasizes a 10-year longevity commitment for its products.

Evolution of STM32 Mainstream MCUs for Digital Power Control

STMicroelectronics has evolved its mainstream MCUs to meet the demands of digital power control:

• STM32F334: Features Cortex-M4 core at 72 MHz and High-precision Timer V1 (10 channels, 217 ps resolution).
• STM32G474: Features Cortex-M4 core at 170 MHz, includes a Math Accelerator, and High-precision Timer V2 (12 channels, 184 ps resolution).
• STM32H745/725: Features Cortex-M7 core at 550 MHz, includes a Math Accelerator, and High-precision Timer V2 (12 channels, 2.2 ns resolution).

These MCUs are mapped against memory size (32KB to 2MB) and pin count (32-pin to 128-pin), with STM32F334, STM32G474, and STM32H74x families occupying different positions based on their capabilities.

Brief Introduction to Successful Digital Power Application Cases

Communication/Server Power

This application requires:

• High-precision timers
• Rich analog peripherals (ADC/COMP/DAC)
• Fast calculation capabilities
• Communication interfaces (e.g., CAN)
• Operation at ambient temperatures up to 125°C.

The system architecture typically involves a primary side (AC input, Input Filter, PFC, DC/DC PRI HF INV) and a secondary side (Power Transformer, DC/DC SEC Output Rectifier, Output Filter), often utilizing MCUs like the STM32G474 on both sides.

Uninterruptible Power Supply (UPS)

Key features for UPS applications include:

• High-precision timers
• Multi-channel PWM generation
• Rich analog peripherals (ADC/COMP/DAC)
• Fast calculation requirements, potentially using Cordic acceleration
• Multiple communication interfaces
• Operation at ambient temperatures up to 125°C.

The system typically includes AC/DC PFC and DC/AC Inverter stages, managed by MCUs such as STM32H743/STM32G474.

Solar Inverter

Solar inverters benefit from:

• Complex PWM generation mechanisms
• Fast calculation capabilities
• Rich peripheral requirements
• Dual-bank, large-capacity Flash RAM.

The architecture involves DC/DC-MPPT and DC/AC Inverter stages, with MCUs like the STM32H743 managing power conversion and communication (e.g., CAN, RS485) via HMI and PLC interfaces.

STM32G4/H7 Advantages in Applications

The STM32G4 series offers enhanced performance and richer peripherals, making it suitable for various digital power applications. Key features include:

• Performance: Arm Cortex-M4 core at 170 MHz, delivering 213 DMIPS and 550 CoreMark® results, with optimized dynamic power consumption (163 µA/MHz).
• Rich Analog Peripherals: Includes operational amplifiers (with gain), DACs, comparators, 12-bit ADCs up to 4 Msps (with hardware oversampling to 16-bit), and CAN-FD up to 8 Msps.
• Functional Safety & Security: Features dual-bank Flash with ECC, secure memory areas, AES-256 hardware encryption, SIL, Class-B compliance, and SRAM parity checking.
• Product Catalog: Complements the existing STM32F3 series, with temperature ranges from -40°C to 85°C or 125°C.
• Accelerators: Includes ART Accelerator™ for dynamic caching, a Math Accelerator for trigonometric functions and digital filtering, and a CCM-SRAM Routine Booster for static caching.
• Advanced Timers: High-precision Timer V2 (184 ps resolution) and USB Type-C Power Delivery 3.0 support.
• Connectivity & Features: 1% internal RC oscillator accuracy, secure online upgrades, and functional safety design packages.
• Package Options: Available from 32 to 128 pins, with Flash memory ranging from 32KB to 512KB.

Integration of peripherals on-chip helps reduce PCB size and BOM cost. The STM32G4 series provides a wide array of analog peripherals, including ADCs, DACs, comparators, and op-amps, supporting diverse application scenarios.

A comparison table highlights the differences between STM32G4 variants (G474 High-performance PWM, G473 Performance, G431/G491 Entry-level) in terms of core, memory, peripherals, and supply voltage.

High-Performance Product Portfolio

STMicroelectronics offers a range of high-performance STM32 microcontrollers, with CoreMark scores demonstrating their processing capabilities:

• STM32F2: 298 CoreMark
• STM32F4: 608 CoreMark
• STM32F7: 1082 CoreMark
• STM32H7 series: Featuring Cortex-M7 cores at various frequencies (280 MHz, 480 MHz, 550 MHz) and dual-core configurations (Cortex-M7 + M4), achieving CoreMark scores up to 2778 (single core) and 2424+800 (dual core).

STM32H7 Product Application Positioning

The STM32H7 family offers diverse options for various applications:

• STM32H743: Single-core 480 MHz with rich resources, suitable for industrial, medical, and consumer applications.
• STM32H745: Dual-core architecture, 125°C temperature rating, and high processing power, ideal for demanding industrial environments.
• STM32H747: Integrates MIPI DSI, meeting requirements for both high performance and display capabilities.
• STM32H7A3: Features large 1.4MB SRAM and low power consumption, suitable for home appliance and industrial display applications.
• STM32H723: Offers the strongest single-core performance and cost-effectiveness, targeting cost-sensitive industrial, medical, and consumer applications. This is a latest release.

STM32H7 Main Features

Key features for STM32H74x and STM32H72x series include:

• Cortex-M7 Core: 480 MHz for H74x, 550 MHz for H72x, with high CoreMark and DMIPS scores.
• Memory: Includes I-Cache, D-Cache, ITCM, and DTCM for fast access. H74x offers up to 2MB internal Flash (dual-bank, on-the-fly updates, ECC) and 1MB SRAM. H72x offers 1MB Flash (ECC) and 564KB SRAM.
• Bus Architecture: 64-bit AXI bus for high-speed data transfer.
• Floating Point Unit: Double-precision FPU included.
• Peripherals: A wide range of peripherals including ADCs, DACs, COMP/OPAMP, HRtimer, FMAC/Cordic, CAN, Ethernet, USB OTG, and more, with variations between H74x and H72x series.

HRtimer - More Than Just High Precision

The HRtimer peripheral offers advanced capabilities for digital power control:

• High-Precision PWM: Supports 12-channel PWM output with up to 184 ps resolution (equivalent to 5.4 GHz timer clock). It features self-compensation and no temperature/Vdd drift.
• High-Flexibility PWM: Comprises a master timer and 6 slave timers that can be cross-synchronized. It supports up to 32 set/reset events per PWM period and allows Master/Slave configuration.
• Multi-Event Response: Integrates 6 analog/digital error inputs and 10 event inputs, with configurable responses for events like counting, windowing, or timeouts.
• 12 Independent Output Channels: Supports various topologies, such as 1x 12 PWM for LLC converters or 12x 1 PWM for buck controllers. The HRTIM unit also supports advanced DMA functions for parameter updates.

Higher Security

STM32 microcontrollers integrate advanced security features for robust protection:

• Secure Firmware Install (SFI) and Upgrade (SFU): Protects firmware integrity.
• Securable Memory Area: Configurable size, can be secured once, and offers no further access or debug capabilities, suitable for critical data and routines.
• Firmware IP Protection: Safeguards intellectual property.
• Secret Key Storage: Secure storage for cryptographic keys.
• Secured Communication & Authentication: Enables secure data exchange and device verification.
• Task Cloisoning: Isolates different tasks for enhanced security.
• Secure User Memory: Features AES encryption, True Random Number Generator (TRNG), PCROP (Proprietary Code Read-Out Protection), MPU protection, and CRC.

Making Digital Power Design Simpler

STMicroelectronics' STM32G4 and STM32H7 series, particularly with the full-featured HRTIM, simplify digital power design. Key benefits include:

• HRTIM Capabilities: 184 ps precision, flexible PWM waveform configuration, rich event management, and fast fault protection.
• Application Support: Applicable to a wide range of power solutions including Wireless Charging, Welding, Industrial applications, UPS, Communication Power, Power Factor Correction (PFC), Motor Control, Lighting, Solar Inverters, and Server/Data Center Power Supplies.

The architecture allows for efficient interaction between timers, comparators, and other peripherals, facilitating complex control loops.

More Performance

The 170 MHz Arm Cortex-M4 core, equipped with three accelerators, delivers enhanced performance:

• CPU Performance: Operates at up to 170 MHz, achieving 213 DMIPS and 550 CoreMark® results.
• Hardware Accelerators:
• ART Accelerator™: Provides dynamic caching for faster code execution.
• CCM-SRAM Routine Booster: Offers static caching for deterministic real-time execution.
• Math Accelerator: Includes Cordic (for trigonometric functions) and FMAC (for digital filtering) to offload the CPU.

The performance is illustrated through a graph showing code execution performance versus wait states and CPU clock speed.

HRTIM Overview (F3 & G4 Series)

The HRTIM offers a modular architecture with a master timer and 6 cross-synchronizable slave timers. Key features include:

• High Resolution: 184 ps output resolution.
• Self-Compensation: Immune to temperature and Vdd variations.
• Up to 12 PWM Outputs: Flexible PWM generation capabilities.
• Event Handling: Supports multiple fault/event inputs and complex event processing (blanking, windowing, timeouts).
• DMA Support: Allows for efficient parameter updates.

The STM32G4 series further enhances this with an additional timer unit (F).

Shaped for Control

The ARM Cortex-M4 core at 170 MHz, coupled with its FPU, DSP capabilities (fast MAC, SIMD), parallel processing, and low interrupt latency, provides a powerful platform for control applications. ST's product architecture integrates:

• ART Accelerator™ for wait state removal.
• CCM-SRAM Accelerator for real-time execution.
• Math Accelerator for Cordic (Trigonometry) and FMAC (Filtering).
• 5x 12-bit 4Msps ADCs with features like SAR, low latency, low aperture time, simultaneous sampling, and hardware oversampling.
• PWM Timers (170 MHz, HRTIM 184 ps) with direct hardware paths for instantaneous control and protection.
• Multiple Fast Comparators, DACs, and PGAs for analog signal processing.
• Other Timers for quad encoders and Hall-effect sensors.

The flexible bus matrix facilitates easy use of analog and digital resources.

Math Accelerators

STMicroelectronics provides dedicated math accelerators to offload the CPU:

• 1. Cordic (Trigo): Essential for Field Oriented Control (FOC) of motors, it performs vector rotation (polar to rectangular: Sin, Cos) and vector translation (rectangular to polar: Atan2, Modulus), along with Sinh, Cosh, Exp, Atan, Atanh, Sqrt, and Ln functions.
• 2. Filter Math Accelerator (FMAC): Used for generating FIR and IIR filters, compensators (like 3p3z for digital power), Sigma-Delta modulators, and noise shapers.

Detailed tables show the precision and number of iterations required for various Cordic functions.

FMAC Implementation: D-Power Buck Converter Example

An example demonstrates the FMAC implementation in a D-Power buck converter. The system integrates ADC, FMAC, and HRTIM for control. Key aspects include:

• 200kHz Switching Frequency: The converter operates at a high switching frequency.
• ADC Triggering: The ADC is triggered by the high-side rising edge.
• Performance: The FMAC execution time, including ISR, is 223 ns, resulting in less than 5% CPU load at 200kHz switching frequency.
• Latency: Hardware latency includes ADC (264 ns) and FMAC (inc. DMA) (200 ns), totaling 464 ns. Software tasks involve FMAC readouts and HRTIM writes.

Reference is made to application note AN5305 for further details.

Reference Documents

STMicroelectronics provides several application notes for further learning:

• High-Precision Timer HRTIM: AN4539: HRTIM Cookbook - How to operate the Hi-Resolution timer in different topology.
• Math Accelerator Cordic: AN5325: Getting started with the CORDIC accelerator using STM32CubeG4 MCU Package.
• Math Accelerator FMAC: AN5305: Digital filter implementation with the FMAC using STM32CubeG4 MCU Package.

More Resources

Explore additional resources from STMicroelectronics:

• Community: community.st.com
• STM32G4: www.st.com/STM32G4
• STM32H7: www.st.com/STM32H7
• Online Training: STM32G4 Online Training
• Wiki: wiki.st.com/stm32mcu
• GitHub: github.com/STMicroelectronics
• Blog: STM32G4 blog articles