Powering the IIoT
While industrial systems can be quite clever, from fine control of heavy loads through to incredible precision and accuracy, each function encounters a common issue: the tradeoffs of power. Today’s challenges primarily revolve around efficiency, which impacts many other aspects of the design. For example, highly efficient designs develop less heat, which means passive dissipation can often displace forced air cooling. As industrial systems become more highly integrated, it is also vital to reduce the size and weight of power converters. Magnetics, such as transformers and inductors, can only be reduced by increasing switching frequencies, something that also demands improvements in switching technology and a move to Wide Bandgap (WBG) devices.
Powering FPGAs
The quality of the power delivered plays a significant factor in the precision of the system being built. For example, the output of CMOS image sensors can vary considerably if the voltage to the internal Analog-to-Digital Converters (ADCs) is not kept within the margins required. Digital devices, such as MCUs, DSCs, FPGAs and other SoC devices, also need stable power, often delivered with specific sequencing to ensure correct startup and shutdown.
Processors such as the PolarFire® FPGA and SoC families demand multiple supplies for core logic, input/output pins, the internal Phase-Locked Loop (PLL) and any transceivers used. Synchronous buck power modules such as the MIC33M350 deliver up to 3A current at programmable core voltages ranging from 0.6V to 3.3V from a 2.4V to 5.5V input voltage.
They use a Constant On-Time (COT) control architecture switching at around 1.2 MHz to provide a conversion efficiency of 95% with a ±1.5% output accuracy over line, load and temperature. Thanks to its HyperLight Load® mode, the module offers very high efficiency at light loads and an ultra-fast transient response. With a high level of integration, only input and output capacitors are needed to complete the design.
Analog PWM controllers for power supplies still command a lot of market share. However, with the growth in connectivity and monitoring through IIoT, there remains an open question regarding the integration of the intelligence required. Digitally Enhanced Power Analog (DEPA) devices retain the benefits of analog power control loops by augmenting them with digital oversight. Solutions such as the MCP19214 support various topologies (boost, flyback, Ćuk and SEPIC) to deliver two outputs from an input of up to 42V using independent control loops. The integrated 8-bit processor is used to configure reference voltages, slope compensation and other parameters while also offering I2C to implement PMBus® communication.
Digitally Enhanced Power Analog
Full digital power is supported by the dsPIC33 family of DSCs with a built-in DSP engine for implementing digital control loops with both dynamic and predictive algorithms. The high-precision Pulse-Width Modulation (PWM) modules, offering 250-ps duty cycle, phase shift, period and dead time control, are complemented by high-speed analog and are well suited to implementing Power Factor Correction (PFC) and other topologies. Reference designs also provide a starting point for high-power solutions, such as a 30 kW Vienna 3-phase PFC.
This leverages the latest WBG Silicon Carbide (SiC) technology, such as 1200V SiC diodes and 700V SiC MOSFETs.
One key challenge for digital power is developing and implementing the control loops for the DSC, but this is simplified thanks to the MPLAB PowerSmart™ memory starter kit. Supporting the dsPIC® DSC family, the kit offers multiple tools to rapidly develop discrete compensation filters from the first to sixth order. It then generates digital Switch Mode Power Supply (SMPS) controller code, eliminating the need to write DSP source code that is imported into MPLAB X IDE for the MCU. Communication software and low-level drivers that use the other DSC peripherals can be defined using the MPLAB Code Configurator (MCC) Melody.
Full Digital Power
Silicon Carbide (SiC) Solutions
MPLAB Code Configurator Melody
