Samsung SCH-211 Service Manual

Samsung Electronics - Contents may change without notice.5-14Circuit Description5-8 Rapid Travel ChargerRapid Charger, TC59-US is composed of power supply part and control part.5-8-1 Power Supply Part (Flyback typeSMPS circuit)AC INPUTAC input protection circuit and rectifier circuitAC power through the AC plug is rectifiered toDC power of high voltage through the D1, D2, D3,D4, C1 and C2. MOV1 is used by protection circuitfrom AC power surge. F1 is fuse to prevent overcurrent. L1 and L2 is EMI noise protection filter ofswitching power.Switching controller and transformerU1 supplies constant voltage and constant currentto secondary circuit through the transformer. D5,D6 absorbs the reverse voltage when transformerwinding turns off.SECONDARY POWEROutput constant voltage circuit : U4, D24, R17The HIC detects output voltage and compares itwith reference voltage in HIC. The error is FED toprimary circuit by U2B. The feeback error is con-verted to current by U2A and D7. The currentcontrolls U1.Secondary rectifier circuit : D21, C21The secondary AC output of transformor isrectified to DC voltage.Secondary filter circuit : L20, C22It minimizes the high frequency ripple noise,which is caused by primary oscilation.Reverse current protection circuit : D20When power is off, it protects the reverse flow ofcurrent from battery pack.5-8-2 Control PartMICOM CONTROLLER : U4U4 is include u-COM to controlled whole chargingsystem and include following internal circuit :-General Input/Output port-A/D converter-Reset delay circuit (Power on delay)-TimerIt is carried following functions :-Battery Recognition-Charging termination condition detection-Output short detection and output protection-Temperature detectionBATTERY RECOGNITION CIRCUIT : U4Battery identity detection determined to voltagedetection battery internal between ID and GND.