This paper demonstrates a signal analysis system-on-chip (SoC) consisting of a general-purpose RISC-V core with vector extensions and a fixed-function signal-processing accelerator. Both the application core and the accelerators are design instances produced through an agile design-space exploration process by generators that allow for a wide range of parameter configurations. The signal processing chain consists of generated instances of a time-interleaved analog-to-digital converter (ADC) followed by a digital tuner, a finite-impulse response (FIR) filter, a polyphase filter, and a fast Fourier transform (FFT) all connected to the five-stage, in-order RISC-V Rocket processor via an AXI4 bus. The generator-based design methodology is detailed, along with the agile design process of producing the fabricated design instance. The 5 mm x 5 mm chip is implemented in a 16-nm FinFET process and operates at 410 MHz at 750 mV drawing 600 mW. Presented applications show coupled functionality of the application processor and accelerator performing spectrometry and radar receive processing, and a comparison with other state-of-the-art application-specific integrated circuits (ASICs) proves that generators can produce performance-competitive designs.

This work demonstrates a RISC-V vector microprocessor implemented in 28 nm FDSOI with fully integrated simultaneous-switching switched-capacitor DC-DC (SC DC-DC) converters and adaptive clocking that generates four on-chip voltages between 0.45 and 1 V using only 1.0 V core and 1.8 V IO voltage inputs. The converters achieve high efficiency at the system level by switching simultaneously to avoid charge-sharing losses and by using an adaptive clock to maximize performance for the resulting voltage ripple. Details about the implementation of the DC-DC switches, DC-DC controller, and adaptive clock are provided, and the sources of conversion loss are analyzed based on measured results. This system pushes the capabilities of dynamic voltage scaling by enabling fast transitions (20 ns), simple packaging (no off-chip passives), low area overhead (16%), high conversion efficiency (80%-86%), and high energy efficiency (26.2 DP GFLOPS/W) for mobile devices.