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4-7-5 Mechanical Specification
- CASE SIZE : 140.8mm°ø54.4mm°ø23.9mm
- CASE MATERIAL : PC (LEXAN 940)
- COLOR : BLACK
- WEIGHT : 110g
4-7-6 Explanation Of Operating
BASIC CIRCUIT CONFIGURATION
Ttavel charger is consisted with power supply and
charging controller, And this charger is also
specified to input filter, rectifier, transformer,
secondary filter, feed-back circuit, battery charging
control circuit and LED display.
OPERATING IN EACH BLOCK
Input Filter, Rectifier
The AC power, which comes from AC-input line,
is changed to DC power by following through F1,
VA1, C01, LF1, D1, C03, C04.
(there are F1 for over current protection, VA1 for
input surge protection, C01, LF1 and C02 for
reducing noise, D01 for converting AC to DC. )
Switching Controller & Transformer
When DC power of 2.1 makes Q01 to turn-on by
biasing gate of it through r03 ~ r07, the current of
primary winding of T1 increases.
As a result, the energy of primary accessary
winding accelerates turn-on of Q01, and the pick
current of primary main winding makes q02 to
turn-on by converted voltage to R02. this result
reduces gate voltage of Q01, the current of
primary main winding consequently. this makes
reverse bias energy to gate of Q01, it is turn-off
quickly. The energy transfers to secondary
winding at that time.
Samsung Electronics
Feed Back Circuit
The transferred energy is rectified and flattened by
D20, C21 and C22.
The case of non-battery and off-state of Q20,
output voltage is regulated to 8VDC by feed back
sampling voltage divided by r27 and r28/r29.
U21 offers reference, compares this to sampling
voltage and send the difference to PWM control
circuit by OP1.
Battery Charging Control and LED Display
Circuit
In the case non-battery, LED is off state by being
on state of q24.
*refer to below table
OUT-A
OUT-B
L
U23
L
U24
When battery is inserted and the voltage of
comparator U23A Term.#3 is higher than the
voltage of Term.#2, LED is RED color by being
OFF of q24, and q21 is off because of U23A is 'L'
OUT-A
OUT-B
L
U23
H
U24
When battery voltage is increased to the point that
the voltage of U23A Term.#3 is higher than the
voltage of Term.#2, battery charging current
follows because q21 and Q20 are ON.
OUT-A
OUT-B
H
U23
H
U24
Circuit Description
q21
q20
H
OFF
OFF
L
q21
q20
L
OFF
OFF
L
q21
q20
H
ON
ON
H
4-15
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