The Research Of Voltage Regulator Module Based On Synchronous Rectification

With the high-speed development of information technology, every kind of data processor, computer, communication and portable equipments gain rapid improvemement, whose integration and working frequency of core part microprocessor chip is continually enhanced. This demands that dynamic response of power supply is faster and faster, that the voltage is lower and lower, that the current is larger and larger, at the same time, that the output voltage with comparatively lower ripple is assured and that it raises higher claim to the volume and efficiency. To meet the requirements mentioned above, the DC/DC converter with low voltage, large current output Voltage Regulator Module is needed to resettle at the microprocessor chip nearby.In the research field of voltage regulator module at present, the study is concentrated in voltage regulator module with the structure of the isolated transformer, especially it is required that the dynamic response and the efficiency of the complete machine are improved, meanwhile, the power supply requirement of rapid impulse response is needed by micro-processing chip to satisfy it.The topology structure of the half-bridge circuit with current-double rectifier converter system is determinated. Making use of mode of the gate charge retention drive, a new self-driven scheme for synchronous rectification is presented, then the paper gives out the solution method that the synchronous rectification could not driven by conventional self-driven when transformer driving winding voltage is zero, also, the control scheme of system is given out.Through the research of the VRM output transient response in this paper, the conception of the critical inductance is introduced, the selected way of critical inductance is presented, the concrete measure of reducing the VRM output ripple is enduced. The influence of VRM output capacitance distributing parameter is discussed, and the restriction relationship of the output inductance, the critical inductance, the VRM output ripple and the system bandwidth is derivedIn the paper, the even model of VRM small signal state space is established, the stability of the system is analyzed. The compensation tache is designed. Also, the parameter of compensating net is given out. In this paper, the VRM model circuit and transformer are designed , and, also, filter network and parameter calculation of coupled-capacitance in series is offered. The experiment result indicate: the self-driven effect of rectifying tube is nice ,and the efficiency of complete machine is high.The research made in this paper has important significance and appropriate value in the technology research and development of voltage regulator module.