The STNRG328S is a digital controller for STC/HSTC open loop resonant converter from STMicroelectronics. It performs a power conversion from an input voltage in a typical range of 40 V to 60 V to an output voltage with a programmable conversion ratio from 2:1 to 10:1 with fixed duty cycle and programmable frequency from 140 kHz to 300 kHz.

It’s able to deliver an output power in the range from 500 W up to 2 KW with very high efficiency in wide load range and with efficiency peak of 98.4% .

A State Machine Event Driven (SMED) implements the control strategy to ensure all the STC/HSTC control functions, in particular the ZCD (Zero Current Detection) feature allows a management of the deadtime and the switching frequency in order to achieve the perfect LC resonance and top efficiency independently from the external component variations.

The STNRG328S firmware is specifically designed to program the SMED and implement the control strategy.

• Digital controller for STC/HSTC topologies
• Support wide conversion ratio from 2:1 to 10:1 to provide several Vout
• State Machine Event Driven (SMED) to implement key control features:
  • Current limit in combination with Hot swap controller
  • Operating input voltage window
  • Conversion ratio control
  • PWM frequency and deadtime management to guarantee ZCD function
  • Soft-start control
  • Driver management
  • Temperature control
• Typical application: Server DC/DC intermediate bus generation from 40 V to 60 V input voltage, 200 W to 2 kW output power range
• Peripherals
  • 10-bit ADC
  • UART interface
  • I²C master fast/slow speed rate
  • GPIOs
• Memory
  • Flash and EEPROM with read-while-write (RWW) and Error Correction Code (ECC)
  • Program memory: 32 Kbytes Flash; data retention: 20 years at 55 °C after 1000 cycles at 55 °C
  • Data memory: 1 Kbyte true data EEPROM; data retention: 20 years at 55°C after 1000 cycles at 85 °C
  • RAM: 6 Kbytes
• Operating temperature: -40 °C up to 105 °C
• Package: VFQFPN32 5x5 mm