Research On Miniaturized DC/DC Converters With Low Temperature Co-fired Ceramic Technology

As a necessary module of all electronic products,higher design requirements are applied to the power supply by degrees.In order to solve the problem that magnetic components occupy most of the volume in the switching power supply,various new materials and packaging technologies emerge one after another.Low temperature co-fired firing technology(LTCC),as a kind of new material technology,not only possesses good temperature characteristics and high frequency characteristics and good heat dissipation,but also possesses a low loss,a small size,a low height,flexible integration and other advantages.It is widely used in the integration of passive devices.Based on the LTCC technology and the diversified three dimensional inductance structures,four miniaturized low temperature co-fired ceramic DC/DC converters were designed and implemented in this paper.The feasibility of LTCC integration technology in the design of miniature power supply unit is further verified.In this paper,the experiment of the substrate was done and the reliability of LTCC ferrite substrate material used in converter design was verified based on the LTCC process.Then the DC/DC converter was constructed from three aspects: the topology of the DC/DC converter,the modulation mode of the DC/DC converter and the working mode of the DC/DC converter.Then,three step-down DC/DC converters and one step-up converter were designed by using two non-isolated converter topologies.After continuous testing and evaluation,the miniaturization of the main control chip of four types of converters has been realized.Then the power inductance,input and output capacitance and feedback circuit of the peripheral circuit were built,and the number of passive components was reduced on the basis of ensuring the electrical performance.Finally,the PCB test circuits of four DC/DC converters were realized.In this paper,a basic inductance model was built on the basis of the three dimensional spiral inductance.On this basis,a new inductance model was established by adjusting the winding mode to reduce the inductance volume by nearly 1/4.By changing the physical parameters and optimizing continuously,four inductance models of the converters were designed,which can ensure high efficiency and sufficient current resistance at the corresponding frequencies.In this paper,the converter was tested and the result was obtained.The solution of adding non-magnetic layer and substrate surface layer was presented,which verified that the electromagnetic interference of the optimized converter model was greatly reduced.Then,some small capacitors were replaced by the close spacing between the output layer and the formation,and the number of passive devices was reduced.Finally,the layout was optimized.