公开(公告)号：US5140175A

公开(公告)日：1992-08-18

申请号：US651364

申请日：1991-05-03

申请人： Keiji Yagi ,  Kazuhiro Zenba ,  Yukihiro Sekiguchi ,  Fumio Ishikawa ,  Tetsuo Yamamoto ,  Takayuki Aoki

发明人： Keiji Yagi ,  Kazuhiro Zenba ,  Yukihiro Sekiguchi ,  Fumio Ishikawa ,  Tetsuo Yamamoto ,  Takayuki Aoki

IPC分类号： H01S5/042 ,  H03K17/0412 ,  H03K17/60 ,  H05B33/08

CPC分类号： H05B33/0818 ,  H03K17/04126 ,  H03K17/603 ,  H05B33/0803 ,  H01S5/0428 ,  Y02B20/347

摘要： A light-emitting diode drive circuit of the present invention comprises: a current supply circuit (3) including a first transistor (16), the base of which receives a first drive pulse signal (S3) output from a signal input circuit, and a second transistor (15), the collector of which is connected to a light-emitting diode (2), the emitter of which is connected to a current source (24) together with the emitter of the first transistor (16), and the base of which receives a second drive pulse signal (S2) having a phase opposite to that of the first drive pulse signal (S3); a fall time shortening circuit (6) including a third transistor (13) which is connected in parallel with the light-emitting diode (2) and the base of which receives an input for short-circuiting both terminals of the light-emitting diode (2) during a turn-OFF time; and a rise time shortening circuit (5) including a circuit (4) for generating a peaking current during a turn-ON time of the light-emitting diode (2), and a fourth transistor (14) being connected in series with the third transistor (13) and adding the peaking current to the drive current during the turn-ON time of the light-emitting diode (2), wherein rise and fall times of the light pulse output are shortened to greatly increase a response speed of the light-emitting diode (2) having poor inherent response characteristics, such as a red light-emitting diode having a short wavelength range.