US 12,451,281 B2
Load drive device and method for controlling electronic control device
Yasuo Shima, Hitachinaka (JP); and Yoichiro Kobayashi, Hitachinaka (JP)
Assigned to Hitachi Astemo, Ltd., Hitachinaka (JP)
Appl. No. 18/282,585
Filed by Hitachi Astemo, Ltd., Hitachinaka (JP)
PCT Filed Mar. 4, 2022, PCT No. PCT/JP2022/009514
§ 371(c)(1), (2) Date Sep. 18, 2023,
PCT Pub. No. WO2022/219965, PCT Pub. Date Oct. 20, 2022.
Claims priority of application No. 2021-066959 (JP), filed on Apr. 12, 2021.
Prior Publication US 2024/0161956 A1, May 16, 2024
Int. Cl. H01H 47/00 (2006.01); H01F 7/18 (2006.01)
CPC H01F 7/1844 (2013.01) [H01F 7/1811 (2013.01); H01F 2007/1888 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A load drive device comprising:
a microcomputer; and
a driver circuit that drives an inductive load by a pulse width modulation signal of a constant cycle based on a control command from the microcomputer, wherein
the driver circuit includes
a current monitoring circuit that monitors a current flowing through the inductive load, and
a disconnection diagnosis circuit that detects disconnection of the inductive load based on a current value detected by the current monitoring circuit, and
the disconnection diagnosis circuit obtains a change amount of a current value detected by the current monitoring circuit, and when the change amount is equal to or less than a predetermined threshold, determines that the inductive load is disconnected and notifies the microcomputer of the disconnection, wherein
the disconnection diagnosis circuit obtains the change amount from a current sampling value sampled in a cycle shorter than one cycle of the pulse width modulation signal of the constant cycle.