Research And Design Of High Efficiency, Multi-modes, Multiple-outputs Power Management ICs For Portable Electronic Devices

Recently,Battery-operated portable electronic devices such as cellular phones and other palm-size devices are in great demand in consumer electronic market.High performance Power management ICs are mandatory in these devices for maximizing the system run time and extending operational life of the battery due to the slow development of battery technology.Furthermore,in order to decrease the size,weight and cost of these devices,miniaturization,low cost and high integration of the power modules are essential.In this paper,high Efficiency,multi-modes, Multiple-outputs Power Management ICs for Portable Electronic devices are researched and designed based on mix-signal CMOS process.The following works have been completed:In order to meet the demand of conformity and integration of power management ICs which are applied in portable electronic devices,a novel architecture of power management system on single chip is proposed in this paper.This architecture are composed of two LDO linear regulators, two DC-DC step-down converters,a linear charger of battery,a logic controlling module,an I²C serial-BUS and registers.The proposed structure is an integrated Power Management System IC for portable applications powered by one Li-Ion or Li-Polymer cell,and which require multiple rails.Moreover,this single chip of power management IC can cooperate with other modules and be managed by portable system due to the using of programmable logic control and I²C serial-BUS.An unconditionally stable low-dropout regulator and low quiescent current is proposed.The LDO based on a high precision CMOS current reference,which is comprised of sub-threshold transistors and has small temperature coefficient,provides a low quiescent current of approximately 4μA.Furthermore,by utilizing the design method of Pole-Zero Tracking Miller Frequency Compensation,the proposed LDO's stability is independent of the load or the equivalent series resistance(ESR) of the off-chip capacitor.The chip design is based on 0.5um CMOS mixed-signal process of CSMC.The experimental results show that the quiescent current is 3.9μA and the operation temperature range is -40～130℃.The dropout voltage is only 170mV at 150mA output current when output voltage is 3.3V.The output noise is 150μV_RMS when frequency range is from 22Hz to 80 kHz.The proposed LDO with ultra quiescent current,high stability and low noise is suitable for portable applications.In this work,detailed theoretical derivation of loop modeling of switching DC-DC converters is described.Based on theoretic analysis,a novel technology about loop modeling of switching DC-DC converters is proposed.The Current-mode model and voltage-mode model with their advanced frequency compensation are presented according to the new modeling technique, respectively.Sequentially,the simulation results are showed to prove the loop model.Based on the accurate loop model of switching DC-DC Converter,High stability and high efficiency step-down DC-DC converters with pulse-width modulation(PWM) and pulse-frequency modulation(PFM) modes are presented.Under nominal load current(>80mA),These converters operate in PWM mode with fixed switching frequency of 1MHz.At light load current(<80mA), the conveters enter PFM mode operation with reduced switching frequency and less quiescent current.Therefore the converter achieves the highest efficiency over the entired load current range. Moreover,an advanced fast response voltage mode control scheme achieves superior line and load regulation.A 300mA output current converter and a 750mA output current converter have been implemented with CSMC 0.5-μm 2P3M CMOS mix-signal process,respectively.Measured results indicate that these converters can automatically switch between PWM-mode and PFM-mode according to the load current.The maximum efficiency of the converter is up to 96.5%and the efficiency is more than 55%at 0.02mA load current.The proposed chips are especially suitable for portable systems powered by 1-cell Li-Ion or 3-cell NiMH/NiCd batteries.Based on research of LDO and DC-DC converters,a novel step-down DC-DC converter with multi-modes of PWM,PFM and LDO modes is proposed.Under nominal load current (80～750mA),This converter operates in PWM mode with fixed switching frequency of 1MHz;at light load current(5～80mA),the conveter enters PFM mode operation with reduced switching frequency and less quiescent current;when the current is ultra light load(0～5mA),the converter is switched to linear regulator and operates in LDO mode with low noise and low ripple output voltage.This converter is designed based on 0.5-μm 2P3M CMOS mix-signal process,and the simulation results show that the proposed converter can smoothly switch between three modes according to the load current.The maximum efficiency of the converter is up to 96%.In this work,LDO,DC-DC converters and linear charger have been implemented and measured with CSMC 0.5-μm 2P3M CMOS mix-signal process.These modules can be integrated together with other blocks of power management system,and then a novel solution based on single chip for power management system of portable electronic devices can be obtained to take the place of traditional solution based on separate chips due to it's small size,programmable control and low cost.