Regulation characteristics of the step-down switching regulator which operates оn a rechargeable battery

Abstract

The aim of the work is to study the peculiarities of the operation of a step-down switching regulator in the case, when a battery operating in a buffer mode is connected to its output. The analysis of its regulating characteristics in the case of presence and absence of a capacitor of a large capacity at the input of the regulator was carried out. It is noted that in the presence of a battery at the output of the voltage regulator, the latter will operate in the mode of regulating the output current (battery charging current). It is shown that in order to ensure the maximum possible energy transferred from a source of electrical energy to a battery, a capacitor with a sufficiently large capacitance must be installed on the input of the switching regulator. The regulation characteristics are obtained for different values of the ratio of the battery voltage and the power source. The conditions under which the maximum possible power is transmitted from the source of electrical energy to the battery are determined. It is shown that under certain conditions, the battery charging current may exceed the short circuit current of the source of electrical energy. The conditions under which a discontinuous current mode occurs in the inductance of the regulator are determined. Taking into account the possibility of such regime, the adjustment of the obtained regulation characteristics was carried out. The regulation characteristics are based on the need to limit the loss of electrical energy in the battery. For this, the maximum permissible value of the relative internal resistance of the battery was determined. If it is necessary to limit energy losses in the power supply, the type of the obtained regulation characteristics remains unchanged. However, in this case, it will be necessary to use a limited portion of these characteristics. It was concluded that when a pulse regulator is operating on a battery, to determine its regulating characteristic, it is necessary to take into account the internal resistance of the power supply. Without taking this resistance into account, the regulating characteristic of the switching regulator are uncertain.