The controller supports the use of various conversion topologies such as boost, SEPIC and floating-load buck-boost regulation. It operates from an input-voltage range of 5.5V to 36V, and supplies an output of up to 60V. It includes a 5V LDO supplying a gate driver for an external MOSFET, and an internal 3.3V LDO supplying the device itself.
The brightness of the LEDs can be controlled in either of two ways:
• enhanced PWM dimming is implemented in tandem with a MOSFET in series with the LED string, and directly driven via a dedicated pin
• analogue dimming at a 10:1 ratio
High-side current sensing, in combination with a P-channel MOSFET, provides effective protection if the positive terminal of the LED string is shorted to ground. Operating at a high level of precision, the current-sensing circuitry enables LED current regulation accurate to within ± 4% over temperature range and production population.
ST also offers an automotive-grade version of this product, the AEC-Q100 qualified ALED6001. This is ideal for automotive exterior lighting systems, including high and low beam and daytime running lights.
- <10μA shut-down current
- External synchronisation for multi-device applications
- Fixed internal soft-start
- Open-drain fault output
- Over-temperature protection
- Output over-voltage protection
- LED over-current protection
- Indoor and architectural LED lighting
- Emergency LED lighting
- Off-grid LED streetlights
- Advertising panels and signage
- White goods
- Gaming and gambling machines
The STEVAL-ILL049V12 evaluation board provides an example of a compact LED driver which implements both the boost and SEPIC topologies.
Orderable Part Number: STEVAL-ILL049V12