Experimental verification of noiseless sampling for buck chopper circuit with current control

Abstract

In digitally controlled circuits for power converter circuits, sampling data is important because a digital control circuit is operated on the basis of these data. If the sampled values have been affected by switching noise from the power circuit, the control stability of the circuit would be disturbed. This paper proposes a noiseless sampling method for both synchronous sampling and multisampling, which can sample a value without being affected by noise. The synchronous sampling method may be affected by noise depending on the duty ratio of the circuit. The noiseless sampling method for synchronous sampling changes the timing of the sampling to a position that is less susceptible to noise. The noiseless sampling method for multisampling does not obtain the data immediately after turn-on and -off switching. The control circuit can avoid switching noise by using noiseless sampling, which leads to a disturbance in the control circuit and enhances the robustness of the circuit when applying the multisampling method. Experimental results are presented to verify that the current control of the proposed sampling methods is not disturbed by noise.