BATTERY CHARGER

• US 3,775,659 A
• Filed: 06/09/1971
• Issued: 11/27/1973
• Est. Priority Date: 06/09/1971
• Status: Expired due to Term

• Current Assignee: George David Ii Carlsen
• Original Assignee: George David Ii Carlsen
• Inventors: Carlsen, George David II
• Primary Examiner(s): Miller, J. D.
• Assistant Examiner(s): Hickey, Robert J.
• Application Number:
  US05/151,447
• Time in Patent Office: 902 Days
• Field of Search: 320/8,2-6,21,61,DIG.2,39,40 322/2,28 321/2
• US Class Current: 320/140
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/0029 with safety or protection devices or circuits
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/00711 with introduction of pulses during the charging process
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: Y10S 320/24 Inductor

Abstract

A battery charger for charging batteries that may have a nominal rated voltage equal to or greater than the voltage of the source, includes an accumulator of energy such as an inductor which is coupled across the source through a controllable switch for a first selected interval of time. The charger further includes a path between the accumulator of energy and the battery to be charged for the transfer of the stored energy to the battery. The path between the accumulator and the battery advantageously includes a unilateral impedance element having a recovery time such that a discharge path is provided for the battery during a second selected interval of time substantially less than the first selected interval of time.

Claims

1. An electrical circuit for charging a battery comprising a blocking diode;

an inductor connectible in series with the diode between a voltage source and a battery to be charged, with the diode being connected on the battery side of the circuit and poled to block current flow from the battery into the circuit;

a timing capacitor network connected across the inductor through a second blocking diode;

an electronic switch having an ON-state and an OFF-state connected to provide when in its ON-state a charge current path therethrough for the capacitor of the timing capacitor network and a current path through the inductor from a source, while bypassing the battery; and

a control circuit including the timing capacitor network and the inductor for alternately switching the electronic switch off and on.

2. An electrical circuit in accordance with claim 1 wherein the control circuit switches the electronic switch off upon the capacitor attaining a preselected voltage.

3. An electrical circuit in accordance with claim 1 wherein the control circuit switches the electronic switch on when the second blocking diode becomes reverse biased.

4. Apparatus for charging a battery from a source comprising an NPN transistor, a PNP transistor, an inductor connected in series with the collector emitter path of the NPN transistor between the positive and negative terminal of the source, the inductor being connected between the collector of the NPN transistor and the positive terminal of the source, a first resistor connected between the collector of the PNP transistor and the base of the NPN transistor, means for connecting the emitter of the PNP transistor to the positive terminal of the source, a second resistor connected between the base of the NPN transistor and the negative terminal of the source, a voltage divider of a third and fourth resistor connected between the positive and negative terminals of the source, the base of the PNP transistor being connected to the junction of the third and fourth resistor, a fifth resistor and a capacitor connected in series between the base of the PNP transistor and the collector of the NPN transistor, a first diode connected between the collector of the NPN transistor and the positive terminal of the battery to be charged, a second diode connected between the base of the PNP transistor and the positive terminal of the source and means for connecting the negative terminal of thE battery to be charged to the negative terminal of the source.

5. Apparatus in accordance with claim 4 further including a second PNP transistor having its emitter connected to the positive terminal of the source and its collector connected to the base of the first PNP transistor, a sixth resistor connected between the base of the second PNP transistor and the positive terminal of the source, a silicon controlled rectifier, a seventh resistor, the anode of the rectifier being connected to the base of the second PNP transistor through the seventh resistor, an eighth resistor being connected between the cathode of the rectifier and the negative terminal of the source, a Zener diode and a potentiometer connected in series between the positive and negative terminals of the battery to be charged, a ninth resistor being connected between the gate electrode of the rectifier and the movable arm of the potentiometer and a capacitor being connected between the gate electrode of the rectifier and the negative terminal of the source.

6. Apparatus in accordance with claim 5 further including a tenth resistor and an eleventh resistor connected in series between the positive and negative terminal of the source and a third diode connected between the junction of the tenth and eleventh resistors and the cathode of the rectifier.