Limited-Pool Random Carrier-Frequency PulseWidth Modulation for digitally controlled dc-dc converters

This paper investigates the application of a limited-pool random pulse-width modulation (RPWM) to high frequency digitally controlled DC-DC power converters. The use of a suitably selected small number of switching frequencies ensures the generation of a flat and widespread spectrum, while limiting the system complexity, especially from the integrated circuit (IC) point of view; moreover the spreading action achieved is almost equivalent to the one obtained with a larger ensemble of frequencies. In the presented solution, the randomization action affects both the switching period and the turn-on interval, realizing the random carrier-frequency modulation with fixed duty cycle (RCFMFD). Moreover, the generation of the random number stream is based on a simple linear feedback shift register. The design of the switching frequencies pool and the evaluation of system performances have been realized using an accurate time-based model of the spectrum analyser. Experimental results on a DC-DC synchronous buck converter, where the digital control has been implemented in field programmable gate array (FPGA), confirm the properties of the proposed solutio

Hysteresis-Based Mixed-Signal Voltage-Mode Control for dc-dc Converters

This paper investigates a mixed signal voltage-mode controller for dc-dc converters based on hysteresis modulation. In the proposed control architecture both switch turn-on and switch turn-off instants are determined asynchronously by comparing the converter output voltage to the voltage ramp driven by the digital control using a digital-to-analog converter (DAC). Under the dynamic point of view, the achievable performances resemble those of a multi-loop control with an internal hysteresis current control based on the estimated inductor current. Moreover, the switching frequency is kept constant under steady-state conditions by modulating the amplitude of the DAC ramp. The proposed control features good dynamic performance, frequency modulation during transients and low-complexity, since it requires a DAC, a comparator and, more importantly, low signal-processing requirement. Simulation and experimental results on a synchronous buck converter, where the digital control has been implemented in a field programmable gate array (FPGA), are also reported

High-Performance Mixed-Signal Voltage-Mode Control for dc-dc Converters with inherent analog derivative action

This paper investigates a mixed-signal fixed frequency digital voltage-mode controller for dc-dc converters. Switch turn-on is determined by system clock, while switch turn-off is determined asynchronously by comparing a signal proportional to the derivative of the output voltage and the voltage ramp driven by the Digital-to-Analog Converter (DAC). One of the most important features is that the derivative action of the Proportional-Integral-Derivative (PID) voltage-mode controller is inherently obtained by a combination of the analog front-end and the hard-wired digital logic, without requiring the digital computation of the derivative action nor any analog derivative circuits. This property potentially enables wide-bandwidth controllers with improvement in dynamic performance respect to conventional digital controllers based on Analog-to-Digital Converters (ADCs) and Digital Pulse Width Modulators (DPWMs). The proposed control architecture is also effective from the IC point of view, since it is based on a DAC, a simple analog front-end and low digital signal-processing requirement. Simulation and experimental results on a 1.2 V - 20 A synchronous buck converter confirm the validity of the proposed solution

\u201cTransmitting apparatus of digital signals on a supply line of electronic devices and corresponding method \u201d

A power converter having a noise component and a modulator configured to vary a frequency of the noise component of the power converter on the basis of a digital signal to be transmitted

Synchronous Asynchronous Digital Voltage-mode control for DC-DC converters

This paper investigates a mixed synchronous/asynchronous digital voltage-mode controller for DC-DC converters. In the proposed control architecture, the turn-on switching event is determined asynchronously by comparing the converter output voltage and a synchronously generated voltage ramp driven by the digital control using a low-resolution digital-to-analog converter. Switch turn-off is determined synchronously by the system clock. In the proposed approach, the derivative action of the proportional-integral-derivative voltage-mode controller is inherently obtained by the frequency modulation, without requiring the digital computation of the derivative action. A simplified small-signal model is also derived in order to analyze the performance achievable by the proposed solution. This control architecture features good dynamic performance, and frequency modulation during transients. Simulation and experimental results on a synchronous buck converter, where the digital control has been implemented in field programmable gate array, confirm the effectiveness of the proposed solution

A PID autotuning method for digitally controlled DC-DC boost converters

This paper proposes a simple PID autotuning technique for digitally controlled DC-DC boost converters using the relay feedback technique. Controller parameter tuning is obtained introducing small perturbations on the output voltage by including a relay in the control feedback and ensuring closed-loop operation during the autotuning procedure. Moreover, including the PID regulator in the relay feedback loop, the controller parameters are directly tuned according to the specified dynamic requirement. The proposed algorithm is simple, it requires small tuning times and it is fully compliant with the cost/complexity constraints of integrated digital ICs. Simulation results and experimental results confirm the validity and effectiveness of the proposed solutio

Digital Deadbeat Control Tuning for dc-dc Converters Using Error Correlation

This letter proposes a simple tuning algorithm for digital deadbeat control based on error correlation. By injecting a square-wave reference input and calculating the correlation of the control error, a gain correction for deadbeat control is obtained. The proposed solution is simple, it requires a short tuning time, and it is suitable for different DC-DC converter topologies. Simulation and experimental results on synchronous buck converters confirm the properties of the proposed tuning algorithm