US 9,812,270 B2
Interlock circuit and image forming apparatus
Ryo Takayama, Osaka (JP)
Assigned to KYOCERA Document Solutions Inc., (JP)
Filed by KYOCERA Document Solutions Inc., Osaka-shi, Osaka (JP)
Filed on Nov. 23, 2015, as Appl. No. 14/948,571.
Claims priority of application No. 2014-240844 (JP), filed on Nov. 28, 2014.
Prior Publication US 2016/0154386 A1, Jun. 2, 2016
Int. Cl. G05B 19/406 (2006.01); H01H 9/54 (2006.01); H01H 3/16 (2006.01)
CPC H01H 9/547 (2013.01) [G05B 19/406 (2013.01); H01H 9/548 (2013.01); G05B 2219/34308 (2013.01); H01H 3/161 (2013.01)] 5 Claims
OG exemplary drawing
 
1. An interlock circuit, comprising:
a power supply line configured to supply a direct-current voltage supplied from a power supply unit to a load;
an interlock switch configured to open and close the power supply line, and including a first node at a side of the power switch unit and a second node at a side of the load;
a time constant circuit connected to the second node in the power supply line and configured to delay a response of a power supply voltage to be applied to the power supply line when the interlock switch closes the power supply line;
a first switch connected between the time constant circuit and the load; and
a switch control unit configured to smooth a voltage difference between the first node and the second node and turn off the first switch when an obtained smoothed voltage becomes larger than a threshold value.