Design Of CC&CV Primary-side Switching Power Supply Controller

More than half of batteries equipped for portable consumer electronics products (such asmobile phones, digital cameras, tablet PCs and MP3players, etc.), that require the switchingpower supply with a regulatory function of constant current (CC) and constant voltage (CV)to charge. However, current and voltage sensing in the secondary side will make the circuitmore complex and lead to additional costs and result in sensing loss, therefore, it has moreimportant theoretical and engineering value to research the primary-side switching powersupply controller with CC&CV function.In the first place, the Primary-Side Regulation (PSR) technique for switching powersupply controller is researched. After a careful analysis on the primary control circuit, a CC&CV PSR controller is designed. PSR controller through the primary circuit detects the outputcurrent of the transformer without TL431and Opto-coupler, improving the reliability of thesystem, effectively reducing the circuit size and lower cost. Meanwhile, the PWM/PFMmodulation technique effectively reduces the loss of light-load or standby, achieving less than30mW standby power consumption to meet the stringent standby power consumptionstandards.After all module circuits of the PSR controller are designed, the CSMC0.5um40V thickoxide double poly BCD process model is adopted based on the simulation tool Spectreintegrated in the Cadence CentOS4.8(x64) workstation. Moreover, simulation results testifythe feasibility of the designed circuits. Finally, a fly-back converter is built, analyzed andverified under various load conditions. The chip’s operating mode varies with the load, i.e., instandby and light load, heavy load conditions, respectively corresponding to PFM mode andPWM mode meeting the expectations of the design requirements. Simulation data verify thefeasibility and correctness of the theoretical analysis and design methods.