公开(公告)号：US11558943B2

公开(公告)日：2023-01-17

申请号：US17488759

申请日：2021-09-29

申请人： KOITO MANUFACTURING CO., LTD.

发明人： Tomoyuki Ichikawa ,  Ryosuke Matsuhana ,  Satoshi Kikuchi ,  Naoki Kawabata ,  Norito Takahashi

IPC分类号： H05B47/10 ,  H05B45/46 ,  H05B45/325 ,  B60Q1/04 ,  H05B47/17

摘要： A lighting circuit turns on a plurality of semiconductor light sources. Multiple current sources are each coupled to a corresponding semiconductor light source. A switching converter supplies a driving voltage VOUT across each of multiple series connection circuits each formed of the semiconductor light source and the current source. A converter controller employing a ripple control method turns on a switching transistor of the switching converter in response to a voltage across any one of the multiple current sources decreasing to a bottom limit voltage.

公开(公告)号：US11477871B2

公开(公告)日：2022-10-18

申请号：US16874124

申请日：2020-05-14

申请人： KOITO MANUFACTURING CO., LTD.

发明人： Tomoyuki Ichikawa ,  Ryosuke Matsuhana ,  Satoshi Kikuchi ,  Naoki Kawabata ,  Norito Takahashi

IPC分类号： H05B47/10 ,  H05B45/46 ,  H05B45/325 ,  B60Q1/04 ,  H05B47/17

摘要： A lighting circuit turns on a plurality of semiconductor light sources. Multiple current sources are each coupled to a corresponding semiconductor light source. A switching converter supplies a driving voltage VOUT across each of multiple series connection circuits each formed of the semiconductor light source and the current source. A converter controller employing a ripple control method turns on a switching transistor of the switching converter in response to a voltage across any one of the multiple current sources decreasing to a bottom limit voltage.

公开(公告)号：US11653434B2

公开(公告)日：2023-05-16

申请号：US17488850

申请日：2021-09-29

申请人： KOITO MANUFACTURING CO., LTD.

发明人： Tomoyuki Ichikawa ,  Ryosuke Matsuhana ,  Satoshi Kikuchi ,  Naoki Kawabata ,  Norito Takahashi

IPC分类号： H05B47/10 ,  H05B45/46 ,  H05B45/325 ,  B60Q1/04 ,  H05B47/17

CPC分类号： H05B47/10 ,  B60Q1/04 ,  H05B45/325 ,  H05B45/46 ,  H05B47/17

摘要： A lighting circuit turns on a plurality of semiconductor light sources. Multiple current sources are each coupled to a corresponding semiconductor light source. A switching converter supplies a driving voltage VOUT across each of multiple series connection circuits each formed of the semiconductor light source and the current source. A converter controller employing a ripple control method turns on a switching transistor of the switching converter in response to a voltage across any one of the multiple current sources decreasing to a bottom limit voltage.

公开(公告)号：US11617247B2

公开(公告)日：2023-03-28

申请号：US17398036

申请日：2021-08-10

申请人： KOITO MANUFACTURING CO., LTD.

发明人： Norito Takahashi ,  Satoshi Kikuchi

IPC分类号： H05B45/30 ,  H05B45/3725 ,  H05B45/345 ,  H05B45/305 ,  H05B45/325 ,  H05B45/3575 ,  B60Q1/04

摘要： Multiple current sources are coupled in series to corresponding light-emitting elements. Switching converter supplies driving voltage to the multiple light-emitting elements and current sources. Pulse modulator generates pulse signal that transits to on level when the smallest from among voltages across both ends of the multiple current sources falls to bottom limit voltage, and subsequently transits to off level. Frequency stabilization circuit controls pulse modulator such that the frequency of pulse signal approaches its target. Dummy load circuit is configured to lower driving voltage in the enable state, to be set to the enable state when switching transistor continues to be off for a predetermined time, and to be set to the disable state in response to the next turn-on of the switching transistor.