Digital Multimode Buck Converter Control With Loss-Minimizing Synchronous Rectifier Adaptation (original) (raw)
Related papers
Digital loss-minimizing multimode synchronous buck converter control
2004 IEEE 35th Annual Power Electronics Specialists Conference (IEEE Cat. No.04CH37551), 2004
A multi-mode control strategy for a synchronous buck converter operating over a wide load range, is presented. For heavy loads, the converter runs in fixed-frequency continuous conduction mode (CCM). At light loads, it enters discontinuous conduction mode (DCM) with synchronous rectification. At still lighter loads, synchronous rectification is disabled in DCM. At very light loads, the converter operates in variable-frequency pulse skipping mode. The synchronous rectifier (SR) timing is scheduled as a function of the load current, enabling appropriate transition among the modes. An on-line adaptive algorithm to optimize the SR timing, based on power loss minimization, is presented. This control strategy is particularly well suited for a digital controller implementation, since it uses sophisticated computations, while not requiring high analog-to-digital conversion rates.
Digitally Controlled Synchronous Buck Converter
The demand for high performance, more flexible and reconfigurable dc-dc converters has pushed dc-dc converter designers to seek for alternative ways to control the pulse-width modulated switch inside the dc-dc converter. During the past few years, efforts have been put forward both by academics and power semiconductor industries to phase out the most commonly used analog PWM controllers with digital controller with its associated software. This paper presents an experimental result of designing and building a 5W synchronous buck converter that employs a microcontroller to process the output voltage signal and translate it into PWM signal to control the switches inside the buck converter and hence regulating the output voltage. Design requirements, procedures, component selections and measurement results will be described in this paper. In addition, operating performance of the buck converter as a result of implementing the digital controller will also be discussed, along with the description of the actual schematics and the final printer circuit board of the circuit.
CONSTANT ON/OFF-TIME DIGITAL PULSE WIDTH MODULATION CONTROL FOR SYNCHRONOUS BUCK CONVERTER
TJPRC, 2014
This paper describes a constant on/off-time digital pulse width modulation for synchronous buck DC-DC converter to reduce the switching frequency and switching losses. Compared to constant frequency modulation, constant on-time modulation control or constant off-time modulation control can achieve fine time resolution with small circuits. However, the switching frequency increases dramatically for the constant on/off-time modulation method under heavy/light load conditions, respectively. By using this control technique, under light load condition, constant on-time modulation control is used while constant off-time modulation control is adapted under heavy load condition. It eliminates the need of high performance controller and switching frequency can be limited to a certain range. This control technique is verified through simulation and successfully implemented the control strategy in real-time by employing a dSPACE controller 1104.
Variable Frequency Digital PWM Control for Low-Power Buck Converters
—This paper describes digital pulse width modulation (DPWM) controller technique for implementing low-power buck converters. The converter is operated at Discontinuous conduction mode to reduce the losses during switching. A DPWM controller is developed to achieve the best possible transient performance under load current change. Simulation of the converter is carried out using MATLAB/SIMULINK and the results indicate that it has good dynamic performance under load change.
Hybrid digital adaptive control for synchronous buck DC-DC converters
2008 IEEE Power Electronics Specialists Conference, 2008
This paper presents a hybrid digital adaptive (HDA) controller for synchronous buck DC-DC converters. The proposed controller is a combination of a standard constant-frequency PWM control in the vicinity of steady state and a bank of linear switching surface controllers (SSC) with slopes adaptively selected by a supervisor away from the reference. The supervisor selects the appropriate switching surface slope based on the capacitor current estimate and the quantized output error. A stability analysis using Lyapunov functions is presented. Experimental results for a 1.3 V, 10 A synchronous buck converter demonstrate near time optimal responses for a wide range of step load transients.
Autotuning of Digitally Controlled Buck Converters Based on Relay Feedback
IEEE 36th Conference on Power Electronics Specialists, 2005., 2005
This paper proposes a simple autotuning technique for digitally controlled dc-dc synchronous buck converters. The proposed approach is based on the relay feedback method and introduces perturbations on the output voltage during converter soft-start. By using an iterative procedure, the tuning of PID parameters is obtained directly by including the controller in the relay feedback and by adjusting the controller parameters based on the specified phase margin and control loop bandwidth. A nice property of the proposed solution is that output voltage perturbations are introduced while maintaining the closed-loop control of the digitally controlled converters. The proposed algorithm is simple, requires small tuning times and it is compliant with the cost/complexity constraint of integrated digital ICs. Experimental investigation has been performed using discrete components, implementing the digital control in a Field Programmable Gate Array (FPGA). Simulation and experimental results of a 1.5V -5 A synchronous buck converter confirm the effectiveness of the proposed solution.
Design of low-power high-frequency digital controlled DC-DC switching power converter
This paper models a low-power high-frequency digitally controlled synchronous rectifier (SR) buck converter. The converter is a hybrid system with three operation modes. Digital PID controler is used. Key problems such as quantization resolution of digital pulse-width modulation (DPWM) and steady-state limit cycles of digital control switching model power supply (SMPS) are discussed, with corresponding solutions presented. Simulation of a digital control synchronous buck is performed with a fixed-point algorithm. The results show that the described approach enables high-speed dynamic performance.
IEEE Transactions on Power Electronics, 2012
A linear/nonlinear digital controller is presented that allows a Buck converter to recover from a load transient event with near-optimal voltage deviation and recovery time. A novel digital double accumulator calculation block is used to calculate the appropriate pulse width modulation switching time instants. The proposed controller possesses many advantages not demonstrated by a single controller in the previous literature. For example, unlike many previously proposed time-optimal digital controllers, the proposed controller provides an excellent transient response as it is capable of reacting asynchronously to a load transient event. In addition, it is demonstrated that the proposed controller can operate without requiring information pertaining to the Buck converter's output inductor. Furthermore, the proposed controller can be extended to applications that require load-line regulation. Lastly, unlike all previous digital time-optimal controllers, the proposed controller does not require digital multiplier or divider blocks nor does it require 2-D lookup tables. Thus, the controller can be implemented through the use of low-cost field programmable gate arrays or complex programmable logic devices.
A fully digital, self-adjusting, and high-efficiency power supply system has been developed based on a finite-state machine (FSM) control scheme. The system dynamically monitors circuit performance with a delay line and provides a substantially constant minimum supply voltage for digital processors to properly operate at a given frequency. In addition, the system adjusts the supply voltage to the required minimum under different process, voltage, and temperature and load conditions. The design issues of the fully digital power delivery system are discussed and addressed. This digital FSM scheme significantly reduces the complexity of control-loop implementation ( 1800 gates) and power consumption ( 100 W at 1.2 V) compared to other approaches based on proportional-integral-differential control.
Design And Efficiency Comparison Of Synchronous Buck Converter With P, PI, PID Controllers
This paper aims to design P, PI, PID compensators for the control of Synchronous Buck converter to improve its conversion efficiency under totally different load conditions. Since the diode rectifier is replaced by a high frequency MOSFET switch, the Synchronous control technique itself can be enough under serious load condition, to attain higher normal mode performance. However, this system does not hold well in light load condition, attributable to enhanced switching losses. A replacement control technique accompanied with P, PI, PID compensators is introduced within the paper can modify synchronous buck convertor to comprehend Zero Voltage Swithching, while feeding light loads. This is often conjointly least price and extremely economical simple technique while not use of additional auxiliary switches and RLC components. This control technique conjointly proved to be efficient under input voltage variations. Simulation is done in MATLAB Simulink for proving stabilization provided by P, PI, PID compensators for synchronous buck converter.