Cigarette Lighter Adapter - Samsung SCH-2000 Service Manual

4-6 Cigarette Lighter Adapter

4-6-1 Description
This specification describes requirements of
CHG55 cigarette lighter adapter. CHG55 is
designed as an charger for Li-ion battery for
SAMSUNG PCS Phone SCH-2000.
4-6-2 Electrical Characteristic
¶UInput Voltage : 11~ 30V DC (Normal voltage :
13.7V DC)
¶UOutput Voltage : 4.1 °æ 0.02V DC9 (Maximum)
¶UOutput Current :
- Output Current : 0 ~ 740 mA
- Current limited in this unit should be kept 740
°æ 40mA
¶URipple Noise : 0.1 Vp_p (under 600mA load)
¶UFuse Capacity : 250V, 2A
¶UCharging time :
- Standard battery : 4 hours °æ 30 minutes
- Extended battery : 5 hours °æ 30 minutes
4-6-3 Function
PROTECTION CIRCUIT
Protection Circuit is the circuit against the
electrical stress which is occurred at unexpected
condition of the source power of CLA unit such as
reserve voltage or over current.
DETECTION OF MOBILE PHONE
If mobile phone is connected to CLA, the CLA
lamp is on to display whether CLA is operating or
not.
Samsung Electronics
AUTO POWER ON
When a phone is connected to CLA, the power of
the phone will be on automatically.
DUAL LED
This CLA has dual LED.
Green : When battery is fully charged. (over 80%)
Red : When CLA is on charging battery.
4-6-4 Schematic Description
POWER SUPPLY
This circuit supplies HHP & battery with power
received from Cigar Lighter jack of automobile.
POWER CIRCUIT OF CHARGE FOR HHP
POWER & BATTERY
This Switching Regulator produces needed power
for charging HHP power & battery, supplied U1,
D1, D2, C1, C2, L1, R11 from Cigar Lighter jack of
automobile.
CONFIRMING CIRCUIT OF EXISTING
BATTERY OR NOT
U3A reads separated voltage between resistance
battery C/F and R20, controls no. 5 pin of U1
through reference voltage and comparator then
decides to produce Vcc or not.
CHARGE CURRENT CONTROL CIRCUIT
U2A, U4, Q1 and side circuit detects R4's flowing
current, control no. 5 pin of u1 then charge current
and charge voltage.
Circuit Description
4-9