This post explains for the PWM Controller.
The Part Number is OB2279.
The function of this semiconductor is Current Mode PWM Controller.
The package is DIP, SOP 8 Pin Type
Preview images :
The OB2279 is a highly integrated current mode PWM control IC optimized for high performance, low standby power and cost effective offline flyback converter applications.
PWM switching frequency at normal operation is externally programmable and trimmed to tight range. At no load or light load condition, the IC operates in extended ‘burst mode’ to minimize switching loss. Lower standby power and higher conversion efficiency is thus achieved. […]
1. On-Bright Proprietary Frequency Shuffling Technology for Improved EMI Performance
2. Power On Soft Start
3. Extended Burst Mode Control For Improved Efficiency and Minimum Standby Power Design
4. Audio Noise Free Operation
5. External Programmable PWM Switching Frequency
6. Internal Synchronized Slope Compensation
7. Low VIN/VDD Startup Current(3uA) and Low Operating Current (2.3mA)
2. Notebook Adaptor
3. LCD Monitor/TV/PC/Set-Top Box Power Supplies
4. Open-frame SMPS
5. Printer Power
Other data sheets are available within the file: OB2279AP, OB2279CP, OB2279CPA,
0B2279AP, 0B2279CP, 0B2279CPA, 0B2279