High accuracy average output current control scheme for power current converter in critical DCM

摘要

High accuracy average output current control scheme for power current converter in critical DCM is composed of the reference block to generate preset reference; the reference calculation block, based on the power current converter's power topology, the correspondent algorithm is calculated to convert the input reference into correspondent output; the state detecting block, the states of power current converter are detected and the detected signals are converted into the same signal format as one of output from reference calculation block; the error detector is used to detect the error between the outputs from reference calculation block and state detected block and to trigger power driver block to turn off the power switch in the power current converter as the error is cross over zero; the zero state detector is used to detect when the states of the power current converter are cross over zero and trigger power driver block to turn on the power switch in the power current converter; the power driver block is controlled with both the error detector and the zero state detector to drive the power switch in the power current converter; based on the correspondent algorithm, the output of power driver block may be used for synchronizing calculation.;With the invented control scheme, it makes the accuracy of average output current of the power current converter independent of input and output voltages, circuit devices accuracy of the power current converter, and makes the average output current in high accuracy control, control scheme implement in simple and low cost.