SEMICONDUCTOR LIGHT SOURCE DRIVING APPARATUS

摘要

The semiconductor light source driving apparatus includes light source modules, a current control element, a second current detection element, a DC power supply, and a controller. The light source modules each include the following components connected in parallel: a semiconductor light source; a first constant-voltage diode; a series circuit of a first current detection element and a second constant-voltage diode with a lower breakdown voltage than the first constant-voltage diode; and a switching element. The controller controls the DC power supply based on a detection output of the second current detection element. After the first current detection element generates a output in response to an open fault in any of the semiconductor light sources, and then the current control element is turned off, the controller turns on the switching element of the light source module with the open fault, thereby allowing the current control element to be controlled.

主权项

1. A semiconductor light source driving apparatus comprising:
a plurality of light source modules each including the following components connected in parallel:
a semiconductor light source composed of one or more serially-connected semiconductor light source elements;a first constant-voltage diode;a series circuit of a first current detection element and a second constant-voltage diode with a lower breakdown voltage than the first constant-voltage diode; anda switching element, a current control element controlled by pulse-width modulation (PWM) using a PWM signal supplied to an end of the current control element; a second current detection element for detecting current flowing through the light source modules; a direct current (DC) power supply for supplying a DC voltage across a serial connection of the light source modules, the current control element, and the second current detection element; and a controller for controlling the switching element, the current control element, and the DC power supply, wherein the controller controls an output voltage of the DC power supply based on a detection output of the second current detection element; and after the first current detection element generates a detection output in response to an occurrence of an open fault in any of the semiconductor light sources, and then the current control element is turned off based on the detection output of the first current detection element, the controller turns on the switching element of the light source module including the semiconductor light source with the open fault, thereby allowing the current control element to be controlled by the PWM.