Understanding Delta-Sigma Data Converters

On-chip stimuli generation for ADC dynamic test by ΣΔ technique

“…To avoid spectral leakage the signal frequency is chosen to fit one FFT bin. The discrepancy between the spectrum expected from (4-5) and the simulated spectrum can be attributed to the linear scaling effect of the quantizer gain and the randomness of the quantization noise [5,Ch. 4.2].…”

“…If it is software generated its whole noise is the quantization noise. For the generic model of L-th order modulator the discrete noise transfer function is given by [5]:…”

Digital Multi-Bit Sigma-Delta Controller for Synchronous Buck DC-DC Converter

“…DPWM base on sigma-delta modulator consists of a low-resolution low-power DPWM capable of operating at high switching frequencies and a sigma-delta modulator, which improves effective resolution of the core DPWM. The sigma-delta operation is based on the well known noise-shaping concept widely used in analog-to-digital and digital-to-analog converters [8]- [12]. Over several switching cycles, the modulator varies the low-resolution input of the core DPWM, between few possible values to achieve a high-resolution average duty ratio value.…”

“…3, it consists of a low-resolution DPWM (Quantizer), a delay block, and two adders. second order sigma delta controller was selected which is inherently stable [8]. The coefficients (a 1 , a 2 , a 3 and a 4 ) are calculated by using toolbox of Schreier [8].…”

“…It is designed for higher power DC-DC converters, where the power consumption of the controller is not so crucial. In addition at maximum switching frequency the resolution of the DPWM is low [1], [6], [7], [8].…”