Title:
LED DRIVE CIRCUIT
Document Type and Number:
Japanese Patent JP2014197656
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide an LED drive circuit capable of improving a power loss due to a current detection resistor and attenuation of the amount of light emission due to the power loss which have become measurable in a bypass circuit and a current limit circuit, which may be included for changing an operation situation according to a circuit current in the LED drive circuit in which the number of lighting LEDs varies according to a voltage of a commercial AC power supply.SOLUTION: Depletion type FETs 15 and 16, which are a bypass current and a current limit circuit, respectively, are subjected to feed back control by using a voltage across both ends of a current detection resistor 18, and a voltage obtained by dividing the voltage. At this time, resistors 17 and 18 included in a voltage-dividing circuit 10a may have high resistance. An LED drive circuit 10, in which the current detection resistor can be reduced to one, allows a power loss due to the current detection resistor to be reduced with an increase in the amount of light emission.
Inventors:
SAKAI YOSHIAKI
AKIYAMA TAKASHI
GOTO SATOSHI
AKIYAMA TAKASHI
GOTO SATOSHI
Application Number:
JP2013116844A
Publication Date:
October 16, 2014
Filing Date:
June 03, 2013
Export Citation:
Assignee:
CITIZEN HOLDINGS CO LTD
CITIZEN ELECTRONICS
CITIZEN ELECTRONICS
International Classes:
H01L33/00
Attorney, Agent or Firm:
Miyajima 明