Design Of DC-DC Converter For Mobile USB OTG Power Supply

The high precise boost dc-dc is used for portable electronic-products power supply, the DC-DC converter in this paper is used for mobile USB OTG power supply. For the realization of mobile USB OTG function, a boost DC-DC converter is needed which must be satisfied with the USB 2.0 standard. So, the paper implements the high precise boost DC-DC. It's output voltage and driver capacity meet the USB 2.0 standard.In this design of DC-DC converter circuit, the design base on the theory of PWM control mode and the peak current loop control modulation. Entire topology and the sub-block design are satisfied the functional requirement. Primarily, analyses the typical blocks: bias current, band-gap reference, slope compensation, oscillator, and trans-conductance amplifier, and so on. This chip used the standard 0.6μm CMOS process, the input voltage range is from 2.9V to 4.2V, the outputvoltage is 5V, the driver current range is from 10mA to 500mA. There is a novel voltage to current converter implement the slope compensation. Design the current and voltage reference with an excellent temperature character, the temperature range is from -25℃to 85℃. And the frequency of oscillator is adjustable.Base on the analysis of circuit theory and the circuit topology, every sub-block and the entire circuit are simulated by the Cadence Spectre tool. The simulation result both reach the goal, the theory have been verified. Then the layout, layout verification and backend simulation have been done. Finally, the analysis of simulation result prove that the DC-DC converter have the excellent line transient response and load transient response. Compare with the traditional boost DC-DC, this design used the peak current control mode and the slope compensation technique, there is an improvement on the precise and stability, the wide of the driver current range is accord for the USB 2.0 standard.