Batterieladeschaltung

摘要

A power supply 2 is provides the operating voltage for a load 1 and charging current for a battery 3 connected directly in parallel with the load 1. If a first comparator 4 detects that the battery charging current is equal to or greater than a maximum value, the comparator 4 supplies a control signal to a control input 10 of the supply 2 causing its output voltage to be lowered. A control signal from a second comparator 7 causes the supply output voltage to be reduced so that the charging current is almost zero if the battery voltage exceeds a maximum value. The battery 3 may thus be charged with constant current, regardless of variations in the current Ik drawn by the load 1, until the battery voltage attains the maximum value (Fig.2). The maximum current and voltage levels may be adjustably set by potentiometers P1, P2. A third comparator (not shown) may be provided whereby a fully discharged battery is fast charged with a current equal to twice the value set by potentiometer P1, until the battery voltage attains 80% of its nominal value, the charging current then falling to the normal value. The comparator circuitry may be integrated and enclosed with the power supply 2 which may be a PWM switch-mode AC/DC converter. The load 1 may be telecommunication equipment, and the battery 3 may be a 48 V lead acid accumulator.