Research And Design Of Core Blocks In DC/DC Converter

With the widely use of portable electronic products with battery power supply, the requirements to power management chip are more critical. Smaller size, lower power consumption and higher power convert efficiency switching power supply IC has been one of the important trend, which is usually used for driving active matrix, thin-film transistor (TFT), liquid crystal displays (LCD), etc.In this paper, we have analysised and designed a high frequency, high efficiency current-mode control DC/DC single chip switching power supply with UMC 0.6um2P2M BCD processes, which include two high-performance Rail-to-Rail Operational Amplifiers. First, the author briefly introduces the basic principles of the DC/DC converter and PWM (Pulse Width Modulation) and PFM (Pulse Frequency Modulation), then compares the voltage control mode with the current control mode and analyses the merits and drawbacks, respectively. Second, according to the application requirements we have designed the overall topology of the chip, and multiple core blocks of the DC/DC converter have been analysed and designed such as Bandgap Reference,OTP(Over Temperature Protection),Oscillator,Rail-to-Rail Operational Amplifier,Error_Amplifier,PWM Comparator,Time_Delay and UVLO(Under Voltage Lock Out),etc.Based on the principle analysis and circuit design in the previous chapters, the author simulated all core blocks using HSPICE software. The simulation results meet the requirements and the circuit principles have been verified. It is a worthwhile and valuable design experience.