Abstract Self-regulating solid state battery charging circuitry which automatically provides a rippled constant mean fast charge current irrespective of the condition of the battery and automatically changes to a rippled constant mean trickle charge current in response to a near-full-charge battery voltage. On-off triggering of the supply occurs in response to error signals from a current sensing resistance which is in series with the battery and with a low-loss loading coil, the battery receiving current from the energized loading coil through a diode and through the current sensing resistance during off intervals of the supply to thereby achieve high efficiency. Only the frequency and shape of the current ripples change as the battery becomes charged. In response to a near-full-charge battery voltage the current sensing resistance is increased about 10-fold, resulting in a 10fold reduction in charging current and a 10-fold increase in frequency of the current ripples.
Battery charging circuitry comprising: A. a source of DC power supply; B. a circuit including in series an electronic switch, a loading coil, terminals for a battery to be charged, a current sensing resistance, and said souRce of supply, to form a first fast charging circuit when the electronic switch is in on condition; C. a diode connected in bridging relation to that portion of the first charging circuit which includes the loading coil, the terminals of the battery to be charged, and said current sensing resistance, to form a second fast charging circuit utilizing stored energy of the loading coil when said electronic switch is in off condition; and D. electronic circuit means responsive to a predetermined current increase or decrease to respectively trigger said electronic switch to an off condition or an on condition, whereby a constant mean fast charging current through a battery connected to said terminals is maintained.
Claim 2
Dependent Claim
152 words
Battery charging circuitry comprising: A. a source of DC power supply; B. a circuit including in series an electronic switch, a loading coil, terminals for a battery to be charged, a current sensing resistance, and said souRce of supply, to form a first fast charging circuit when the electronic switch is in on condition; C. a diode connected in bridging relation to that portion of the first charging circuit which includes the loading coil, the terminals of the battery to be charged, and said current sensing resistance, to form a second fast charging circuit utilizing stored energy of the loading coil when said electronic switch is in off condition; and D. electronic circuit means responsive to a predetermined current increase or decrease to respectively trigger said electronic switch to an off condition or an on condition, whereby a constant mean fast charging current through a battery connected to said terminals is maintained.
Claim 3
Dependent Claim
29 words
The battery charging circuitry of claim 1, which includes adjustable means to determine the current level through said resistance relative to which said current increase and current decrease occur.
Claim 4
Dependent Claim
43 words
The battery charging circuitry of claim 1 in combination with means responsive to voltage across said terminals indicative of near-full-charge to increase the magnitude of said resistance and thereby reduce the constant mean fast charging current to a constant mean trickle charging current.
Claim 5
Dependent Claim
33 words
The battery charging circuitry of claim 3 including means to change the magnitude of said resistance back to its initial value upon a predetermined drop in said voltage, whereby fast charging is resumed.
Claim 6
Dependent Claim
24 words
The battery charging circuitry of claim 4 which includes adjustable means to determine the mean voltage level relative to which said voltage drop occurs.