STEVAL-ILL037V1

The STEVAL-ILL037V1 is an entry-level 2 W LED Driver Evaluation Board from STMicroelectronics. It integrates a buck converter and a linear current regulator, providing good flexibility and cost efficiency for LED lighting applications. The board offers low-current LED driving, power savings, wide input voltage range and it is suitable for 1 or 2 series LED string.

The STEVAL-ILL037V1 board is designed to be a demonstration platform for the STMicroelectronics L9958 device. It implements a buck converter using the L9958 as PWM external driver, working in discontinuous-current mode (DCM) without secondary switches. The linear current regulator is based on an external MOSFET and employs a proprietary circuit to compensate the LED current and improve the load regulation. The board also contains many helpful features, such as SMD LEDs for visual feedback and power-good indicator, switches for manual operation and current programming, plus short protection for both input and output.

The board is designed to work with an input voltage ranging from 8 V to 36 V and has been optimized for a high efficiency solution. It can be used in high power LED lighting designs where low-cost, high brightness, low-heat, and minimal components are required. The STEVAL-ILL037V1, with its 1A and 2A operation range, is ideal for LED light engines and LED Colour coded systems.

The working principle of the STEVAL-ILL037V1 is relatively straightforward. The board utilizes the L9958 device and an external MOSFET to provide PWM dimming and LED current regulation. The PWM input is fed to the L9958 and it controls the on-time of the MOSFET. The external MOSFET passes the current through the LED load, depending on the on-time of the MOSFET. The LED current is regulated by the external MOSFET and this is done by setting the duty cycle of the PWM signal.

The board is designed to operate in two modes, providing either constant LED current or constant light output. In constant LED current mode, the LED string current is regulated by setting the PWM duty cycle. In constant light output mode, the current is adjusted automatically to maintain a constant light output, regardless of changes in the LED supply voltage. The board also includes a bicolor LED power-good indicator, so that it is clear when the board is operating correctly. This indicator glows green when the board is functioning correctly and will display red in case of an over-temperature or overload condition.

In conclusion, the STEVAL-ILL037V1 is an entry-level 2 W LED Driver Evaluation Board from STMicroelectronics that is ideal for LED light engines and LED colour coded systems. It implements a buck converter and a linear current regulator and the board offers low-current LED driving, power savings, wide input voltage range and it is suitable for 1 or 2 series LED string. It has been designed to work with an input voltage ranging from 8 V to 36 V and has been optimized for a high efficiency solution.