| 摘要 |
PROBLEM TO BE SOLVED: To provide a drive circuit capable of measuring the resonance frequency of a VCM with spring return mechanism.SOLUTION: In a step for generating a control signal S2 on the basis of a command value S1 for designating the target stroke volume of a VCM200 during normal driving thereof, and measuring the resonance frequency fo of the VCM200, a control signal generation unit 20 generates a control signal S2 which vibrates during a forced vibration period and maintains a fixed value during a subsequent measurement period. A drive current generation unit 10 supplies a drive current Idependent on the control signal S2 to a coil L1 in the VCM200. In the step for measuring the resonance frequency fo, during a measurement period, a period measurement unit 40 measures the period of a coil voltage detection signal Vc corresponding to a coil voltage Vappearing across the coil L1 in the VCM200. |
