Protection of battery-powered devices against accidental swap of power supply connections.

Abstract

Objectives. Battery-powered devices (e.g., wireless sensors, pacemakers, watches and other wrist-worn devices, virtual reality glasses, unmanned aerial vehicles, robots, pyrometers, cars, DC/DC converters, etc.) are widely used today. For such devices, it is highly important to ensure safe primary power supply connection, including protection against reverse polarity. The conventional solution to the reverse polarity problem, involving the use of Schottky diodes during system redundancy or increasing power by combining two or more power supplies in the OR-ing circuit due to a large voltage drop, results in significant power losses at high currents, heat dissipation problems, and an increase in the mass and size of the equipment. For this reason, it becomes necessary to develop efficient batterypowered equipment protection against incorrect reverse polarity connection.Methods. The problem is solved using circuit simulation in the Electronics Workbench environment.Results. When protecting equipment against reverse voltage polarity, it is shown that the minimum level of losses and low voltage drop are provided by “ideal diode” circuit solutions based on discrete components and microcircuits of the “integrated diode” type with external and internal power metal–oxide–semiconductor field-effect transistors (MOSFETs). The circuit simulation of ideal diodes based on p- and n-channel transistors with superior technical parameters allows the characteristics and voltage and power losses in the protected circuits to be specified along with a presentation of the proposed technical solution simplicity. The contemporary component base of protection devices is discussed in terms of efficiency.Conclusions. Examples of equipment for protecting against reverse voltage polarity are given along with circuit solutions based on discrete and integrated components. The simulation of the transfer characteristics of protection devices shows the limit for the minimum input voltage value of around 4 V using a MOSFET transistor.