发明授权
US5140175A Light-emitting diode drive circuit with fast rise time and fall time 失效
发光二极管驱动电路具有快速上升的时间和时间

Light-emitting diode drive circuit with fast rise time and fall time
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.
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