CPC H01F 7/1844 (2013.01) [H01F 7/064 (2013.01); H01H 1/54 (2013.01); H01H 47/22 (2013.01); H01F 2007/1888 (2013.01)] | 15 Claims |
1. A coil driving device, comprising:
an input voltage sensing unit for detecting an input voltage;
a switch unit configured to make a switching operation to supply a driving current to a coil;
a pulse width modulation (PWM) circuit unit for outputting a PWM signal for the switching operation of the switch unit;
an impedance adjustment unit for changing an impedance value such that the PWM signal is adjusted, thereby limiting the driving current; and
a control unit for causing the impedance adjustment unit to change the impedance value on the basis of the input voltage, thereby adjusting at least one of the duty ratio of the PWM signal and the frequency thereof.
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