Solution Description
Electrical standards, for switched-mode power supplies, demand increasingly higher power conversion efficiency, which in high power applications often implies costly active power factor correction stages to improve the harmonics and power factor on the mains AC supply line.
The SL-DPSTPFC1, bridgeless Totem Pole PFC with full digital control, has proven in comprehensive testing and measurements to deliver low THD across wide input voltage and load conditions, and near unity power factor for high efficiency digital power supply applications.
The STM32F334 microcontroller implements fine control loop regulation over wide operating ranges, ensuring high system reliability with smart inrush current control. Its rich set of analog peripherals, coupled with the totem pole architecture, contribute to reducing the overall bill of materials and consequent solution cost and size.
The power section features very high performance 650V Silicon Carbide Power MOSFET in the high frequency leg, driven by the STGAP2S galvanically isolated gate driver. The low frequency leg instead uses 30A 1200V SCR thyristors to provide AC line polarity switching with active current limitation at power up or line drop recovery.
A flyback circuit based on VIPer26LD high voltage converter completes the design by providing regulated voltages to both the power and control sections.
A complete firmware application is included for reference, which can be modified according to specific application requirements.
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Key Product Benefits
STM32F469AI high perfromance MCU
The STM32F4 series Cortex-M-based microcontroller, with FPU, high performance NVM and accelerator technology is chosen for its digital signal processing capabilities and high clock speeds to manage the very high data rates arriving from the vibration and environmental sensors.
SCTW35N65G2V Power MOSFET
This 2nd generation Silicon Carbide Power MOSFET (650V, 45A, 55 mΩ) features extremely low reverse recovery losses, which is critical for low ripple current CCM operation in high power totem pole solutions, as well as excellent on-resistance and switching characteristics that remain largely unaffected by junction temperature.
STM32F334 High performance 32bit MCU
This MCU line with 32-bit Arm® Cortex®-M4 is especially suitable for running highly responsive control algorithms for cycle by cycle current control and tight voltage regulation in digital power conversion applications such as D-SMPS. The MCU features a high-resolution timer, high-speed ADCs for precise and accurate control, and an assortment of analog interfaces for protection and signal conditioning.
STGAP2S high power gate-driver
This 4A single gate driver isolates the gate driving channel in high power applications from the low voltage control and interface circuitry. It's low propagation delay inside 80 ns ensures the high PFC control accuracy, with UVLO and thermal shutdown protections and a standby mode to ensure very low idle power consumption.
TN3050H-12WY SCR Thyristor
This highly robust automotive grade SCR Thyristor provides inrush current limitation with high robustness to surge and immunity to electrical transients, without the bulk and reliability issues associated with alternatives using NTC and mechanical relays.
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VIPER26LD 800V MOFET
This high power MOSFET with 800 V breakdown voltage ensures a highly efficient auxiliary power supply with extended input voltage range and enables a smaller DRAIN snubber circuit.
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All Features
- Very high Power Factor and low THD solution ensuring high efficiency power supplies
- Robust design that meets EMC standards up to 4kV with high switching lifetime and reduced EMI emissions
- Use of SiC MOSFET boosts efficiency while allowing a more compact high output power design
- Application and operation flexibility with STM32 MCU ensuring precise and highly responsive digital control
- Improved reliability with active soft start inrush current limitation and galvanic Isolation between the control and power stages
