Title:
ＬＥＤ駆動回路
Document Type and Number:
Japanese Patent JP7006866
Kind Code:
B2
Abstract:
To provide an LED drive circuit that automatically performs switching between serial/parallel connection of two LED groups depending on input voltage and makes it possible to visually and easily confirm abnormality such as non-lighting of either one of the LED groups and desired current not flowing through the LED groups.SOLUTION: An LED drive circuit comprises: LED groups 2, 3; switch circuits 7 to 10; a drive circuit 6 for controlling current flowing through the LED groups 2, 3; current detection circuits 11, 12 for detecting the current flowing through the LED groups; a control circuit 13 including current comparator circuits 132, 133 for comparing constant current generated by a constant current generation circuit 131 with the current flowing through the LED groups; and a control circuit 5 that performs individual ON/OFF control on the switch circuits 7 to 10 using a detection result of input voltage VIN and a control signal for the control circuit 13 and controls respective drive units of the drive circuit 6. The control circuit 13 controls a switch control circuit 52 so as to turn on the switch circuits 7 to 10 when current values of the LED groups 2, 3 are abnormal.SELECTED DRAWING: Figure 1
Inventors:
Fujiwara sect
Kenji Takebuchi
Tomoharu Yada
Yoshinori Kato
Yamazaki Ohyoshi
Kenji Takebuchi
Tomoharu Yada
Yoshinori Kato
Yamazaki Ohyoshi
Application Number:
JP2017153479A
Publication Date:
January 24, 2022
Filing Date:
August 08, 2017
Export Citation:
Assignee:
New Japan Radio Co., Ltd.
International Classes:
H05B39/06; H01L33/00
Domestic Patent References:
| JP2009252344A | ||||
| JP2016201514A | ||||
| JP2004527138A | ||||
| JP2017127166A | ||||
| JP2015167213A |
Foreign References:
| US20130033194 | ||||
| CN104936330A |