Design Of A Quick Dynamic Voltage Scaled Single Inductor Dual Output DC-DC Converter

With the development of smart handheld device,there are new requirements on the integration density and processing performance of electronic products.SoC technology is widely used due to its high integration density and fast processing speed. SoC system requires the power supply chip with small size,low weight,simple external circuits and mutiple output voltages.For meeting the requirements referred,single inductor dual output(SIDO)converter is widely concerned.Meanwhile,in order to reduce the dissipation,SoC requires the power voltage can response quickly according to the current working status.So dynamic Scaling speed is one of the core performance indicators for SIDO.In order to speed up during dynamic scaling,a new maximum current charging and adding a direct discharging path method based on SIDO converter is proposed. The SIDO converter was based on charted 0.18μm process.Firstly,the thesis established a complete system model.And then based on the model,the SIDO converter was design in detail.The SIDO converter used adaptive common voltage to realise one output voltage while the other one kept stable，which can reduce cross regulation effectively.The main loop used an error amplifier with no frequency compensation,which lead to a substantial increase in transient response.The second loop used an error amplifier with PI compensation,which increased the loop stability. After the circuit design,the thesis accomplished the design of layout and post-layout simulation.The post-layout simulation showed:when the output voltage Vol=1.8V,Io1=200mA,the switch time used by Vo2 from 0.9V to 1.2V was 11.6μs,the switch speed was 38.7μs/V; the switch time used by Vo2 from 1.2V to 0.9V was 17.4μs,the switch speed was 58μs/V. The output voltage ripple was less than 20mV when the load was heavy.while the output voltage ripple was less than 30mV when the load was light.The peak efficiency was lager than 91% during heavy load and lager than 84% during light load,basically meet the design requirements.