Charging control circuit for charging battery

Abstract

The invention relates to a charge control circuit of a rechargeable battery, which comprises a charger, a first diode, a first resistor and a second resistor, wherein, the first resistor and the second resistor are connected with two ends of the battery which is charged after being connected in series, and a cathode of the battery which is charged is earthed. The charge control circuit is characterized in that a third resistor is also in series connected between the first resistor and the second resistor; one path of an anode of the first diode is connected with the anode of the battery whichis charged through the first resistor, and the other path thereof is connected with a negative input end of a comparator; one path of the cathode of the first diode is earthed through a capacitor, andthe other path thereof is connected with a positive input end of the comparator; the negative input end of the comparator is connected with the cathode of the battery which is charged through the second resistor; an output end of the comparator is connected with a control end of the charger. The charge control circuit increases the sensitivity of the comparator by utilizing the small dynamic resistance of the diode and the dynamic partial pressure ratio characteristic of the resistor, rapidly detects and controls the micro-voltage negative increment thereof that is minus Delta V, prevents theover-charging phenomenon of the battery which is charged, and enables the circuit to possess good practicability.

Description

technical field [0001] The invention relates to a charging control circuit for a rechargeable battery, in particular to a charging control circuit for detecting whether a nickel-cadmium or nickel-hydrogen battery is fully charged. Background technique [0002] When charging nickel-cadmium or nickel-metal hydride secondary batteries, it has a remarkable characteristic: that is, the voltage increases with the increase of stored electric energy. When the battery is fully charged, the charging voltage will rise rapidly and reach the maximum value; fully charged After receiving charging, the battery voltage will drop slightly from the highest voltage point, and a negative voltage increment -ΔV will appear. This tiny voltage negative increment - ΔV can be measured through an appropriate circuit (voltage negative increment method) to control the charging current on and off to complete the charging work. [0003] Such as figure 1 As shown, it is a schematic circuit diagram of a ni...

AI Technical Summary

Problems solved by technology

Therefore, the above-mentioned control circuit connection method is likely to cause battery overcharge, and the response sensitivity of the comparator BG' is not high, so it cannot be used in practice. It has certain limitations and needs further improvement.

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