A Design Of An Adjustable Dead-time Driver Circuit

With the development of modern power electronics technology,the miniaturization and weight reduction of power electronic devices have become increasingly demanding.Increasing the operating frequency of power electronic devices can reduce the volume of capacitors,inductors,and transformers in power electronic devices,and is the most direct and effective means for achieving miniaturization and lighter weight of devices.However,if the operating frequency is directly increased,the switching loss of the circuit will increase,the working efficiency will decrease,and the electromagnetic noise will increase correspondingly.Therefore,to increase the operating frequency of the circuit needs to meet the requirements with the soft switching technology.Zero-voltage switching as a type of soft switching has a very important role in reducing switching losses.For this reason,this paper proposes a dead-time drive circuit design for an active clamp forward converter.Moreover,the dead time of the driving circuit can be adjusted according to changes in the parameters of the load and external components,so that the circuit meets the resonance condition to realize zero voltage switching(ZVS).In terms of design methods,this paper analyzes the working principle of the active clamp forward converterfirstly,and the two different clamping modes of the high-side clamp and low-side clamp of the active clamp circuit.Then according to the working principle of the active clamp circuit,the conditions to be met in the dead-zone driving circuit are systematically analyzed and the system framework of the dead-time circuit is proposed.In the circuit design,this article first analyzes the working principle of each circuit sub-module,which includes the dead-time generation module,dead-time control module,in-phase and inverting switching modules,and drive modules.Then use Hspice according to the circuit design to verify the correctness of the circuit design,and adjust the circuit design parameters to meet the requirements based on the simulation results.When the design and simulation of each sub-circuit module meets the requirements,each sub-circuit module is assembled together to form an overall dead-time drive module.Then verify that the entire circuit matches well,the function is normal,and the performance meets the requirements.The dead-time drive circuit involved in this article is based on the BCD process of Huahong Grace 0.5um.The circuit can flexibly adjust the output mode according to the clamp mode of the active forward converter,and the dead time of the driving circuit is linearly adjustable.The dead time adjustment range is about 50-300 ns,which increases its application range.In addition,the on-resistance of the dead time drive circuit is 15-20 ?,the rising edge of OUT_A is 20 ns,the falling edge is 15 ns,and the rising and falling edges of OUT_B are equal.They are all about 15 ns.The simulation verified that the circuit meets the design requirements.