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I would be grateful for a professional translation or
correction of the following text!
Circuit for battery type Gel Charger using lm117
Battery charging is another application uniquely suited for the
LM117.
Since battery voltage is dependent on electro-chemical
reactions, the charger must be designed specifically for the
battery type and number of cells. Ni-Cads are easily charged with
the constant current sources shown previously. For float chargers
on lead-acid type batteries all that is necessary is to set the
output of the LM117 at the float voltage and connect it to the
battery. An adjustable regulator is mandatory since, for long
battery life the float voltage must be precisely controlled. The
output voltage temperature co-efficient can be matched to the
battery by inserting diodes in series with the adjustment
resistor for the regulator and coupling the diodes to the
battery.
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A high
performance charger for gelled electrolyte lead-acid batteries is
shown in schematic. This charger is designed to quickly recharge
a battery and shut off at full charge.
Initially, the charging current is limited to 2A by the internal
current limit of the LM117. As the battery voltage rises, current
to the battery decreases and when the current has decreased to
150 mA, the charger switches to a lower float voltage preventing
overcharge. With a discharged battery, the start switch is not
needed since the charger will start by itself; however, it is
included to allow topping off even slightly discharged batteries
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| When the
start switch is pushed, the output of the charge goes to 14.5V
set by R1, R2 and R3. Output current is sensed across R6 and
compared to a fraction of the 1.2V reference (across R2) by an
LM301A op amp. As the voltage across R8 decreases below the
voltage across R2, the output of the LM301A goes low shunting R1
with R4. This decreases the output voltage from 14.5V to about
12.5V terminating the charging. Transistor Q1 then lights the LED
as a visual indication of full charge.
schematic
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 TO-220
LM117T
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TO-03 LM117K
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| To circuit use package TO-220 or TO-03
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