Rugged enough for high-end industrial applications as well as outdoor equipment such as solar-power converters, EV charging stations and industrial SMPS, the STNRG ICs contain ST’s State Machine Event Driven (SMED) high-resolution PWM generator in combination with an STM8-based supervisory core. The devices integrate 32KB EEPROM, 6KB RAM, an ADC, an op-amp, an I2C port and GPIOs.
Configuring the SMED requires no specialist software competencies, unlike the usual DSP or MCU-based approach. The SMED can be triggered from the internal timer or an external event such as peak current, over current or zero crossing. This allows a peak-current detecting buck converter, with constant off time set by the timer, to operate without intervention by the core processor. A simple proportional-integral loop executed in the core sets the peak-current value for output regulation.
The STNRG family comprises the STNRG288A with four SMED-controlled outputs, the STNRG328A with five SMEDs, and the STNRG388A with six SMEDs. Designers have the option to connect two SMED cells together to generate dual gate-drive signals with inserted dead time for half-bridge configurations. ST’s SMED is already proven as a high-performing solution for digital control in STLUX ICs for LED lighting.
All devices are in production now, priced from $2.20 and sold in 1000-piece quantities.
ST’s will exhibit the STNRG digital-controller family at PCIM 2015, which takes place from 19th to 21st May in Nuremberg, Germany. The company will be located at booth 551 in hall 9.
