Abstract:
A monolithic current mode CMOS DC-DC converter with new control
topology and integrated power switches has been developed in this thesis. A unified
modulator model is also established for the topology, following the steps, used for
deriving familiar models. System and circuit level implementation of the converter
have been accomplished for the converter. Afterwards, this converter has been
fabricated with a standard 0.5 flm CMOS process. The remarkable features of the
converter are complete discharge of the output voltage, pulse-by-pulse current
limiting, pulse-skipping mode in light load operation etc. Modulator gain Fm has been
found to be a finite quantity and is independent of duty cycle, which reveals the fact
that the control loop's stability is independent of compensating signal. In addition, no
external components except the inductor and output capacitor and no extra I/O pins
are needed for the current mode controller. The simulation and test data are in good
agreement. The experiment results show that this converter operates around IMHz
with the supply voltage from 0.8V to SV, which is suitable for single cell lithium-ion
applications. The power efficiency is over 80% for load current from SOmA to
100mA, load regulation 1.6%, for the load variation 0-1OOmA.
