公开(公告)号：EP1878035A2

公开(公告)日：2008-01-16

申请号：EP06750340.9

申请日：2006-04-14

申请人： Ranco Incorporated of Delaware

发明人： HUBER, Terry, Lee ,  RODDA, Dale, Thomas

IPC分类号： H01H47/00

CPC分类号： H02H9/047 ,  F25D21/006 ,  F25D21/008 ,  H01H47/325

摘要： A wide input voltage range relay drive circuit allowing a more than 2:1 input voltage variation is provided. The circuit utilizes a scaled and rectified bulk voltage to drive the relay coil. As the monitored bulk voltage increases beyond the relay coil rated voltage, the circuit pulse width multiplexes this bulk voltage to protect the relay coil. The bulk voltage switching does not begin, however, until the relay energizes. To reduce the power dissipation during the PWM switching, of the relay coil, a power dissipating switch is included and held on during the PWM switching events. To further increase relay life, the circuit controls the energizing of the relay coil to actuate the contacts of the relay at or near a zero cross of the power switched thereby.