Modeling And Design Of Monolithic Switching Regulator In Current-Mode

A high-frequency and high-efficiency monolithic switching regulator in current-mode implemented with 0.35um CMOS process is analyzed in this paper. The chip has a wide input voltage range of 2.6V to 9V to generate adjustable output voltage range of 6V to 13V. A 1.2MHz oscillator circuit is imbedded and along with the function of soft-start. The chip also has some interior protection functions such as UVLO(Under-Voltage Lockout), OVP(Over-Voltage Protection), OTP(Over-Temperature Protection) and OCP(Over-Current Protection). The output current is adjustable simply by changing the external circuits to meet customers' requirements.During the circuit design, the basic principle of switching regulator in current-mode is introduced at first. Then, the comparison between current-mode and voltage-mode is presented in the thesis. As a result, we can comprehend the merits and drawbacks of these two topologies in order to use them freely and specify a new topology of chip according to customer's requirements. A generalized SPICE model for current-mode DC-DC converter operating in DCM(Discontinuous Current Mode) and CCM(Continuous Current Mode) is proposed. With the guide of SPICE model the author designed all modules and several sub-circuits, such as Bandgap Reference, LDO, Current-Sense , Slope Compensation, Oscillator and PWM Comparator are analyzed.Based on the principle analysis and circuit design in the beginning chapters, the author simulated the SPICE model and some sub-circuits and the whole chip circuits in top level using EDA tools HSPICE. The wafer test results after MPW(Multi-Project Wafer) and Full Mask tape-out indicate that the IC(integrated circuit) has met the design specification, both functional targets and electrical characteristics.