DRIVER CIRCUIT FOR EXPANDING AND CONTRACTING ACTUATOR USING SHAPE-MEMORY ALLOY AND LENS POSITION CONTROLLER USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a driver circuit for driving a shape-memory alloy (SMA) actuator with high accuracy.;SOLUTION: A first terminal OUT1 is connected to the other end of the SMA actuator 2 through a detection resistor Rs. A second terminal OUT2 is connected to the other end of the SMA actuator 2. A first switch SW1 and a second switch SW2 are respectively provided between the first terminal OUT1 and the second terminal OUT2, and a ground terminal GND. A D/A converter 10 converts digital control data D_CNT for designating a displacement amount of the SMA actuator 2 into an analog control voltage V_CNT. A comparator 12 compares the control voltage V_CNT with a detection voltage Vs. A control part 16 latches an output S_CMP of the comparator 12 in prescribed timing, and controls ON and OFF of the second switch SW2. A bias circuit 14 generates reference bias voltages VH, VL of the D/A converter 10 according to a power supply voltage Vdd.;COPYRIGHT: (C)2010,JPO&INPIT