A drive apparatus includes a light emitting device, a light receiving device configured to receive light emitted by the light emitting device, a comparison circuit configured to compare a light quantity of light detected by the light receiving device with a target value indicating a light quantity of light to be emitted by the light emitting device and generate a control signal corresponding to a comparison result, and a drive circuit configured to supply a drive signal corresponding to the control signal to the light emitting device. The drive circuit includes a gain changing switch configured to change, in accordance with the target value, a gain of the drive circuit.

A first current generator circuit generates a first current having a current value variable in accordance with a first control signal. A second current generator circuit generates a second current by limiting the first current so as to have a current value variable in accordance with a second control signal. A third current generator circuit generates a third current by limiting the second current so as to have a current value variable in accordance with a third control signal, and supplies the third current to the semiconductor laser element. Rates at which the first and second control signals change are set to be lower than a rate at which the third control signal changes.

A first current generator circuit generates a first current having a current value variable in accordance with a first control signal. A second current generator circuit generates a second current by limiting the first current so as to have a current value variable in accordance with a second control signal. A third current generator circuit generates a third current by limiting the second current so as to have a current value variable in accordance with a third control signal, and supplies the third current to the semiconductor laser element. Rates at which the first and second control signals change are set to be lower than a rate at which the third control signal changes.

A drive apparatus includes a light emitting device, a light receiving device configured to receive light emitted by the light emitting device, a comparison circuit configured to compare a light quantity of light detected by the light receiving device with a target value indicating a light quantity of light to be emitted by the light emitting device and generate a control signal corresponding to a comparison result, and a drive circuit configured to supply a drive signal corresponding to the control signal to the light emitting device. The drive circuit includes a gain changing switch configured to change, in accordance with the target value, a gain of the drive circuit.

The present invention provides a programmable continuous wave high power laser diode system, which comprised digital control unit, a switch module unit, and a latch current controlling unit so as to provide user to set the latch current of the high power laser diode via the digital control unit controlling the switch module unit and the latch current controlling unit, therefore, the laser diode system includes advantages of high system efficiency, reliability, low output ripple current range and fast switching reaction time.

The invention provides a light generating system (1000) comprising a first light generating device (110), a second light generating device (120), a third light generating device (130), a luminescent material (200), and a control system (300), wherein: (A) the first light generating device (110) comprises a first laser light source and is configured to generate first device light (111) having a first device peak wavelength (.sub.1) and having a first spectral power distribution; wherein the first device peak wavelength (.sub.1) is selected from the wavelength range of 445-475 nm; (B) the second light generating device (120) comprises a second laser light source and is configured to generate second device light (121) having a second device peak wavelength (.sub.2) and having a second spectral power distribution, different from the first spectral power distribution; wherein the second device peak wavelength (.sub.2) is selected from the range of 420-450 nm or from the range of 470-490 nm; (C) the luminescent material (200) is excitable by the first device light (111) and the second device light (121); wherein the luminescent material (200) is configured to convert at least part of one or more of the first device light (111) and/or the second device light (121) into luminescent material light (201) having a centroid wavelength .sub.c,1 within the green-orange wavelength range; the luminescent material (200) has an absorbance band having a first absorbance E1 at the first device peak wavelength (.sub.1) and a second absorbance E2 at the second device peak wavelength (.sub.2), wherein E2/E1<1; (D) the third light generating device (110) comprises a third laser light source and is configured to generate third device light (111) having a third device peak wavelength (23) selected from the wavelength range of 600-650 nm; (E) |.sub.1.sub.2|20 nm; .sub.1 and .sub.2 are selected from the wavelength range of 420-490 nm; and |c,.sub.1.sub.3|20 nm; (F) the control system (300) is configured to control at least the first light generating device (110) and the second light generating device (120): (G) the light generating system (1000) is configured to provide in an operational mode white system light (1001).

A control method of speeding up light emission of a laser diode includes the following steps. First step is to boost the supply voltage from a first voltage potential to a second voltage potential before an emission period. At the beginning of the emission period, a current path conducts through the laser diode and a current source. One terminal of the laser diode is coupled to the current source, and the other terminal of the laser diode connects the supply voltage. When the current path is being conducted, the current source is in the transient state and provides a transient driving current; and the voltage difference between the two terminals of the laser diode is generated in response to the second voltage potential and is related to the transient driving current. When the transient driving current is larger than a threshold, the laser diode emits light.