Research On Three-dimensional Integrated High Power Synchronous Rectifier

Synchronous rectifier which is short for AC/DC power conversion device is to use power electronic devices to convert AC to DC.It has the advantages of low power consumption,high efficiency,high reliability and high integration.The reliability of electronic systems is vital impacted by the performance of the rectifier.There are three key strategies for high performance synchronous rectifier,keeping the phase synchronization between the gate control signal of MOSFETs and the voltage being rectified,improving the conversion efficiency and making intelligent control.Three-dimensional integration technology can effectively reduce the length of interconnects,improve interconnect density,achieve heterogeneous integration,reduce chip area and reduce manufacturing costs.It is considered to be an important technology for the rapid development of integrated circuit technology.In a three-dimensional integrated system,the power density will increase sharply while the integration is improved.Therefore,heat dissipation is one of the key and difficult points for three-dimensional integrated systems.Thermal reliability problem will become more prominent for three-dimensional integrated power systemsIn this thesis,a series of research work on the circuit design of high-power synchronous rectifier,three-dimensional integrated layout and thermal management of three-dimensional integrated power systems has been carried out.The main contents are as follows:1.A high-power synchronous rectifier circuit has been designed based on HG 700 V 1μm BCD process.It includes error amplifier,voltage comparator,bandgap reference,oscillator,high-voltage step-down regulator,logic controller and protection circuits.All modules are simulated and verified.The simulation results show that the output voltage of the high-power synchronous rectifier is 5V.When the load is 2Ω,the output current is 2.5A and the output power is 12.5W.2.Layout design of the three-dimensional integrated high-power synchronous rectifier.Firstly,the control chip layout and the rectifier bridge chip layout of the synchronous rectifier are designed,respectively.For alignment during the three-dimensional stacking,the size of thetwo-layer chip is designed to be the same.Then,the TSV for interconnection and heat dissipation are placed at corresponding position.Based on the Calibre 3DSTACK tool,the electrical connection of the three-dimensional stacked layout,covering all ports at the top and bottom layers,has been checked.The coordinates of TSV connection holes are coincident.The vertical depth meets the requirement.The TSV electrical connection between the two layers of chips is correct.3.Thermal analysis and thermal design of three-dimensional integrated power systems.Firstly,a three-dimensional integrated power system model,in which the upper,middle and lower power chips are bonded together by silicon dioxide,and the silicon dioxide is mounted on the copper heat sink,is formed.The steady-state thermal resistance model of TSV,the heat transfer path centered on TSV and the relationship between thermal conductivity of bonding layer and thermal load capacity are deep analyzed.Next,three types of internal nested heat dissipation networks based on TSV are designed.Analysis results based on thermal simulation software Flotherm are as follows: The TSV nested heat dissipation network can significantly improve the heat dissipation effect of a three-dimensional power integration system.The heat dissipation effect nested heat dissipation systems with non-uniform TSV is better than that of the nested heat dissipation system with uniform TSV.The heat dissipation effect of nested heat dissipation system with thicker TSVs in the bottom layer chip and thinner TSVs in the top layer chip is the best.Its heat dissipation performance is the most closed to that of two-dimensional planar packaging.