Research On Switch Linearity Hybrid Precise Current Source

With the development of the electronic technology, the higher requirements of Power Supply are raised including high efficiency, high power precision and low EMI. The traditional power meter calibrating source usually has the shortcomings of low efficiency and large volume. Switch-Linearity Hybrid Power conversion is researched and a switch-linearity hybrid precise current source is introduced in this paper to overcome these defects.The novel precise current source consists of a switching power module and a linear power module and takes the advantages of them. A forward DC/DC converter and a hysterisis control inverter used as pre-regulator, A push-pull liner amplifier used as post-regulator. The pre-regulator adjust the input voltage of post-regulator to make push-pull liner amplifier has excellent output waveforms and good stability. A novel self-adaptive three-state hysteresis control method is also proposed to solve the distortion problem in small output current situation. The results of Simplorer simulation prove the feasibility of this current source. A prototype hybrid type of precise current source based on these techniques is designed. Experiments show that this current source has advantages of simple circuit, low ripple quotient, high efficiency and small volume. So it is fit for power meter calibrating system and it can be widely used in the field of precise measurement.