Application of the injected current model for the dynamic analysis of switching regulators with the new concept of LC³ modulator

Abstract

A new generation of switching regulators inbedding an LC3 modulator (limit cycle conductance controller) is analysed and optimized from the point of view of dynamic performances. This is done by application of the current injected technique to the power stage model which is shown to behave like a first order system for low frequency perturbations. The optimization is carried out by specification of the desired closed loop modes of the system and calculation of the appropriate state variable feedback gains. The correctness of both the analytical model and optimisation procedure is verified by breadboard dynamic measurements.

Modelling and analysis of switching DC-to-DC converters in constant-frequency current-programmed mode

“…Thus, this threshold level, rather than the duty ratio, becomes the input port for feedback in the current-programmed mode. In [3], both the turn-on and turn-off times of the switch are determined in this manner, resulting in a free-running converter; in [4], the turn-on times are periodically clocked, leading to a fixed-frequency system, as shown in current. Third, as will be seen from this paper, the current-programmed mode, relative to dutyratio programming, effectively removes one pole from the loop gain, simplifying the design of the feedback network.…”

Input filter interactions in peak-current-mode-controlled buck converter operating in CICM

“…These constraints are typically of the form (15) [21], where denotes the new control variable. The resulting set of state-space equations can be presented as (16), where the subscript extension " " denotes current-mode control (15) …”

“…Peak-current-mode (PCM) control has been a popular control method of switched-mode buck converters since its invention [15], [16]. It differs from the direct duty-ratio control or voltage-mode (VM) control in such a way that the duty ratio is generated using directly the inductor current and not an artificial modulator ramp as in VM control [30].…”

A Study of Two Control Methods for Full Bridge Converters: Soft Switch Bypass and Current Mode Control

“…1 [2][3][4] provides symmetry for the output waveforms and thus avoids transformer saturation. The obvious disadvantage of the circuit is the higher switching loss and EMI that result from forced commutation.…”