The Design Of Buck Converter XD1712 With Chip Ripple Compensation

In recent years,with the rapid development of electronic communications technology,wearable equipment,intelligent terminals,liquid crystal display and other aspects are closely related to our life,power provides energy for them.Due to the efficiency,power consumption,transient response and other advantages,power converter supply is widely used as the main product of power supply.Buck converter is widely used,which adopts the constant on time conduction mode.In general,the output capacitance of buck converter uses electrolytic capacitor.Considering the cost of design and circuit area,the output of buck converter uses ceramic capacitor.However,when working in a high frequency environment,small equivalent series resistance of the ceramic capacitors easily leads to instability of the system.In view of the above problems,this paper designs a buck converter XD1712 with ripple compensation on chip.This paper first introduces the working principle of the converter,and compares the advantages and disadvantages of the three modulation methods,which provides a theoretical basis for the design of the buck converters.XD1712 designs ripple compensation circuit,which is integrated in the chip.Compared with the traditional compensation circuit,the compensation circuit on chip does not need to set additional compensation components in the periphery,so it effectively reduces the circuit area and the complexity of the circuit degree.Sampling the output voltage produces a ripple voltage that is opposite to the phase of inductor current,and compares with the feedback voltage,the output logic signal triggers the time module and the driver module to adjust the output voltage,so that it can make the system stable.XD1712 uses an adaptive on time control mode,which makes the system have fast transient response.The realization process is through the detection of change between input and output signal,the results will be detected to the internal response,and the switching frequency comes into a voltage.Compared with the two voltages prepared in the chip,it outputs the logic single,so as to control the internal logic of driver module.XD1712 has designed a zero current detection module to prevent inductor current sink in the chip,so as to improve the efficiency of the system.XD1712 has also designed a lot of protection modules,such as under voltage lock out,over temperature protection,under voltage protection and other circuits,in harsh environments or unexpected circumstances,to ensure the system work properly.XD1712 adopts 0.5μm BCD 30 V process,using Spectre simulation tool under Cadence platform simulates the sub-module function,verifies the overall performance of the system,and analyses the simulation results.In the allowed input range 4.5~18V,the output of XD1712 is at 1.2V,the transient response is better,and the other performance also meets the design requirements of the system.