21 / 2016-12-10 19:13:53

Milliamperes controllable constant current source design

12052

In the detection of the working resistance of the airbag, in order to make the work can be safe and efficient, in this paper, a high precision and controlled current source is designed. The constant current source consists of two parts, respectively is the constant current source control module and power module. In this paper, the mirror power circuit is used as a constant current source control module, the precision resistor Ro is used as the sampling resistance. The Ro output voltage through AD chip is feedback to the control system, and then through the output current operation program of the DA chip is controlled, and the output current is converted into a voltage, then after adjusting the input amplifier circuit of constant current source voltage control module, the constant current source can be adjusted. Finally, the experimental results show that the maximum error of the DC current source is 3.23%, which meets the requirement of 5%. The maximum ripple factor is 0.00032%, which meets the requirement of 0.001%.