DC/DC Conversion Circuit Design Of Micro Accerleration Interface Circuit

On the basis of the analysis of the principle, performance index of severalbooster charge pump circuits based, a three-level cross coupling structure isestablished to realize DC/DC charge pump circuit composed of more than5v to18vbooster, after work in constructing overall charge pump structure, the band gapreference source, oscillator, comparator, temperature protection module, time controlmodule in detail the design, simulation and optimization of the charge pump circuit,detailed analysis and optimization of the working frequency, pump capacitor, switchconduction resistance, load capacity and load resistance parameters, charge pump andthe no-load and load conditions of the output voltage ripple, drive current, inputvoltage scanning, etc.Considering bulk effect and the influence of threshold voltage loss for voltagegain and efficiency, three-level cascade cross coupling circuit structure is used incharge pump circuits in order to achieve the required voltage. Consider efficiency andpower consumption problems, band gap reference source modules using1-levelop-amp, automatic biasing band gap circuit; Considering reasonable workingfrequency of the charge pump, select oscillator module output frequency1MHz; Inorder to make the comparator with fast transient response, the op-amp outputrequiring cascade two-stage invertor; Considering maximum temperature of circuitwithstanding, temperature protection module set no more than160C; To meet therequirement of charge pump for the clock, select a data selector, two-phase nooverlapping clock circuit and binary frequency circuit consisting of clock controlmodule for the clock signal optimization.Considering charge pump output current, voltage ripple and efficiencyrequirements, the transfer line size, pump capacity, load capacitance and resistanceare analyzed in detail and optimized, and finally reasonable parameter values selectedfor charge pump circuits are analyzed in the whole simulation, getting no load circuitoutput voltage19.95V, ripple of10mV, circuit with load output voltage19.52V,output drive current is100mA, ripple of6.04mV, charge pump efficiency is87.63%,accord with the design requirements.