Compact optical sources and methods for producing short and ultrashort optical pulses are described. A semiconductor laser or LED may be driven with a bipolar waveform to generate optical pulses with FWHM durations as short as approximately 85 ps having suppressed tail emission. The pulsed optical sources may be used for fluorescent lifetime analysis of biological samples and time-of-flight imaging, among other applications.

Compact optical sources and methods for producing short and ultrashort optical pulses are described. A semiconductor laser or LED may be driven with a bipolar waveform to generate optical pulses with FWHM durations as short as approximately 85 ps having suppressed tail emission. The pulsed optical sources may be used for fluorescent lifetime analysis of biological samples and time-of-flight imaging, among other applications.

A weighing scale has a housing accommodating a load cell, having fixed, deformation, movable portions. The fixed portion is connected to the housing, and the movable portion bears a spider having a platter. The deformation portion has a strain gauge measuring a weight acting on the platter. A strip light is attached to an external wall of the housing. A state machine of a controller depicts states of the weighing scale. The controller either: applies a voltage to the strip light in a pulsed manner when the state machine is in a first state, and applies a voltage to the strip light constantly in a second state; or applies a voltage to a third group of LED lamps of the strip light constantly in the first state, and applies a voltage to a second group of LED lamps of the strip light constantly in the second state.

A weighing scale has a housing accommodating a load cell, having fixed, deformation, movable portions. The fixed portion is connected to the housing, and the movable portion bears a spider having a platter. The deformation portion has a strain gauge measuring a weight acting on the platter. A strip light is attached to an external wall of the housing. A state machine of a controller depicts states of the weighing scale. The controller either: applies a voltage to the strip light in a pulsed manner when the state machine is in a first state, and applies a voltage to the strip light constantly in a second state; or applies a voltage to a third group of LED lamps of the strip light constantly in the first state, and applies a voltage to a second group of LED lamps of the strip light constantly in the second state.

A dimming circuit for dimming a current flowing through a light emitting device, having: a multi-function pin, configured to receive a dimming signal; wherein when the dimming signal is an analog voltage signal, an amplitude of the current flowing through the light emitting device is regulated based on the dimming signal; when the dimming signal is a pulse signal and a frequency of the dimming signal is in a first frequency range, a duty cycle of the current flowing through the light emitting device is regulated based on the dimming signal; and when the dimming signal is the pulse signal and the frequency of the dimming signal is in a second frequency range, the amplitude of the current flowing through the light emitting device is regulated based on the dimming signal.

A dimming circuit for dimming a current flowing through a light emitting device, having: a multi-function pin, configured to receive a dimming signal; wherein when the dimming signal is an analog voltage signal, an amplitude of the current flowing through the light emitting device is regulated based on the dimming signal; when the dimming signal is a pulse signal and a frequency of the dimming signal is in a first frequency range, a duty cycle of the current flowing through the light emitting device is regulated based on the dimming signal; and when the dimming signal is the pulse signal and the frequency of the dimming signal is in a second frequency range, the amplitude of the current flowing through the light emitting device is regulated based on the dimming signal.

A method for driving one or more electrically powered light sources, such as LED modules, may include applying a pulse-width-modulated signal thereto having a pulse-repetition frequency and a duty-cycle, the duty-cycle being selectively variable in order to vary the intensity of light emitted by the light source or light sources. To counter the occurrence of temporal light artefacts, or TLAs, the method may include frequency modulating the pulse-width-modulated signal (V.sub.PWM) by varying the pulse-repetition frequency thereof around a certain value between a lower frequency value and a higher frequency value, thus giving rise to a signal with combined FM/PWM modulation.

A method for driving one or more electrically powered light sources, such as LED modules, may include applying a pulse-width-modulated signal thereto having a pulse-repetition frequency and a duty-cycle, the duty-cycle being selectively variable in order to vary the intensity of light emitted by the light source or light sources. To counter the occurrence of temporal light artefacts, or TLAs, the method may include frequency modulating the pulse-width-modulated signal (V.sub.PWM) by varying the pulse-repetition frequency thereof around a certain value between a lower frequency value and a higher frequency value, thus giving rise to a signal with combined FM/PWM modulation.

A control circuit for a constant-current drive circuit, as well as a constant-current drive circuit are disclosed. The control circuit can obtain output information of the constant-current drive circuit and use it in combination with reference information to determine, according to an output condition corresponding to the current load of the constant-current drive circuit, a time point for the system to enter or exit a rapid drive mode. Therefore, it can be suitably used in various application scenarios to determine a time point for the system to entry into or exit from the rapid start mode. Compared with fast charging for a fixed period of time as used in the prior art, embodiments of the present invention can effectively overcome the problem of easy overshooting or inadequate acceleration during start as found in various applications.

A load control device for controlling the intensity of a lighting load, such as a light-emitting diode (LED) light source, may include a power converter circuit operable to receive a rectified AC voltage and to generate a DC bus voltage, a load regulation circuit operable to receive the bus voltage and to control the magnitude of a load current conducted through the lighting load, and a control circuit operatively coupled to the load regulation circuit for pulse width modulating or pulse frequency modulating the load current to control the intensity of the lighting load to a target intensity. The control circuit may control the intensity of the lighting load by pulse width modulating the load current when the target intensity is above a predetermined threshold and control the intensity of the lighting load by pulse frequency modulating the load current when the target intensity is below the predetermined threshold.