Design of high frequency response bi-directional switch type constant current source

YUAN Yue-feng， GUO Bin
（College of Quality & Safety Engineering，China Jiliang University， Hangzhou 310018， China）

Abstract： Aiming at the common drawbacks of present available current sources，such as analog types were only usable for unidirection and low power efficiency，and digital types had both complicated and cost expensive structures but relatively lower response speed，a novel analog PWM control chip based bi-directional high frequency response switching-type current source was proposed. A pulse width modulation control chip MCP1630 and an integrated power H-bridge L6201P were taken as the controller core in the scheme. By precise high side current sampling，error voltage between reference voltage and feedback was generated and sent to MCP1630 inner amplifier to form current PI closed control loop. Experiment results indicate that this current source has a full load output span up to ±2 A with an accuracy of ±5% F.S. The -3 dB bandwidth is over 700 Hz. With fast response performance，low power dissipation and very low cost，it is very suitable for driving high speed bi-directional proportional solenoids.
Key words： high frequency response；bi-directional constant current source；dynamic response；pulse width modulation；closed-loop control