Research And Design Of Key Modules In Digital DC-DC Converter

In the electronic device, the integrated circuit is a indispensable circuit module for circuit system. The integrated circuit chips in the different processes need different supply voltages,but power supply from the battery power or other power supply system can not direct supply power to integrated circuit, so, DC-DC power management chip is the key to the integrated circuit on the normal working.This paper research are based on deeply research for the key technology of switching power supply management chip, design a Digital buck DC-DC switching power supply management chip. The buck digital DC-DC converter using the voltage mode architecture,the error between the feedback voltage and the reference voltage is quantized by the quantizer, and the quantizer output signal input to the digital compensation, when the digital compensation operation completed,the DPWM module translate digital compensation output into pulse signal.Finally,the pulse signal will through dirver module to control the switch on or off state,as to control of DC-DC converter by digital type.At the same time,the chip using synchronous rectification techno logy,reduce the additional power loss.The buck digital DC-DC converter through external control signal to change the chip internal retference voltage to achievethe output voltage jump at the different value, which provides a good solution for device low power management by multi voltage domain. The input voltage of the chip is 5 V, the output voltage range of 1.8V-2.5V. Through the Matlab Simulinlc modeling has been identified the parameters and system structure module, using specture ancd verilogHDL has been completced analog modules(DLL module, drive circuit, current source circiuit and level shift module)and digital modules(DPID and DPWM module) design and simulation.The simulation results show that the converter output voltage of the set up time is about 35us, the stability of the output voltage ripple is about 4mV, the conversion efficiency can reach 90%, the output voltage at system switching state also exhibits good characteristics.Using the SMIC 0.18?m Technology Library, completed in the digital DC-DC mixed circuit simulation, using Cadence virtouso to completed the chip layout(digital part and analog part)that is not contain the power tube.The chip of digital DC-DC conveter has been tape-outed.The preliminary test results show that the key circuit modules(bandgap, DLL, DPID and DPWM etc) are accord with the design request.