US 12,445,032 B2
Current detection circuit, power conversion device, and power system
Akinori Hariya, Tokyo (JP)
Assigned to TDK CORPORATION, Tokyo (JP)
Appl. No. 18/033,661
Filed by TDK CORPORATION, Tokyo (JP)
PCT Filed Oct. 26, 2021, PCT No. PCT/JP2021/039437
§ 371(c)(1), (2) Date Apr. 25, 2023,
PCT Pub. No. WO2022/092065, PCT Pub. Date May 5, 2022.
Claims priority of application No. 2020-182301 (JP), filed on Oct. 30, 2020.
Prior Publication US 2023/0402910 A1, Dec. 14, 2023
Int. Cl. H02M 1/00 (2007.01); G01R 15/18 (2006.01); H02M 3/335 (2006.01)
CPC H02M 1/0009 (2021.05) [G01R 15/183 (2013.01); H02M 3/33584 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A current detection circuit configured to detect a value of a switching current through a detection resistor using a current transformer,
wherein the value of the switching current is detected by switching the detection resistor and a reset resistor on the basis of a flow direction of the switching current flowing on a primary side of the current transformer,
the current detection circuit includes a first diode, a second diode, a first reset resistor, a first detection resistor, a second detection resistor, a first switching element, and a positive voltage level shift circuit,
a series connection circuit of the first diode and the first detection resistor is connected in parallel to a secondary winding of the current transformer,
a series connection circuit of the second diode and the first reset resistor is connected in parallel to the secondary winding of the current transformer,
a series connection circuit of the first switching element and the second detection resistor is connected in parallel to the first reset resistor,
the first diode is connected in a direction in such a way that the first diode is turned on when the switching current flows in a predetermined direction,
the second diode is connected in a direction in such a way that turning-on of the second diode is curbed when the switching current flows in the predetermined direction, and
the positive voltage level shift circuit is configured to convert a negative voltage which is detected through parallel connection of the second detection resistor and the first reset resistor to a positive voltage level.