US 11,864,282 B2
Light-emitting element driving device
Makoto Suyama, Kyoto (JP); Koji Katsura, Kyoto (JP); and Toshiro Okubo, Kyoto (JP)
Assigned to Rohm Co., Ltd., Kyoto (JP)
Filed by ROHM CO., LTD., Kyoto (JP)
Filed on Aug. 19, 2022, as Appl. No. 17/891,311.
Claims priority of application No. 2021-150863 (JP), filed on Sep. 16, 2021.
Prior Publication US 2023/0090191 A1, Mar. 23, 2023
Int. Cl. H05B 45/14 (2020.01); H05B 45/345 (2020.01); H05B 45/50 (2022.01); H05B 45/46 (2020.01)
CPC H05B 45/14 (2020.01) [H05B 45/345 (2020.01); H05B 45/46 (2020.01); H05B 45/50 (2020.01)] 20 Claims
OG exemplary drawing
 
1. A light emitting element driving device, comprising:
an external terminal, configured to connect to a first terminal of a light emitting element;
a constant current circuit, connected to the external terminal; and
a current detection unit, configured to detect a current flowing through the constant current circuit, wherein
the current detection unit includes:
a first transistor, including a first end, a second end and a control end connected to the external terminal;
a current setting resistance, connected to the second end of the first transistor; and
a drive amplifier, including:
a first input end, connected to a first node to which the first transistor and the current setting resistance are connected;
a second input end, to which a current set voltage is applied; and
an output end, connected to the control end of the first transistor, and wherein
the current detection unit converts the current flowing through the light emitting element into a voltage signal based on a feedback voltage generated in the first node, and generates a current detection signal.