Monolithic Power Systems supplies a range of LED drivers (and associated evaluation boards) suitable for either step-down or inverting step-up/down applications.
The MP248x family achieves up to 2,5 A peak output current over a wide input supply range with excellent load and line regulation. Current mode operation provides fast transient response and eases loop stabilisation. Fault condition protection includes thermal shutdown, cycle-by-cycle peak current limiting, input over-voltage protection, open string protection and output short circuit protection. The devices incorporate both DC and PWM dimming onto a single control pin. A separate input reference ground pin allows for direct enable and/or dimming control for a positive to negative power conversion.
The MP4000 is a high-efficiency step-down converter which can handle mains AC supply and is designed for driving high-brightness LEDs. It drives an external MOSFET in the floating buck converter structure. The inductor current is regulated with boundary conduction mode which features no reverse recovery loss in the freewheeling diode and soft turn-on for the power MOSFET.
The LED current can be well regulated by controlling the MOSFET peak current, which is sensed through an external resistor. Its low 300 mV feedback voltage reduces power loss and improves efficiency. The MP4000 can accept an external PWM or a DC signal for burst dimming control. It features output short circuit protection, maximum switching frequency limit, under-voltage lockout and thermal shutdown.
The MP4020 is a triac dimmable, single power stage, isolated, primary-side controlled offline LED lighting controller that achieves high power factor and flicker-free triac dimming in a single SOIC8 package. The proprietary real-current control method can control the LED current accurately from the primary side information. It can significantly simplify the LED lighting system design by eliminating the secondary side feedback components and the optocoupler.
The MP4020 integrates active power factor correction and works in boundary conduction mode in order to reduce MOSFET switching losses. Its low startup current and quiescent current reduce total power consumption to provide a high-efficiency solution for lighting applications. The device features over-voltage protection, short circuit protection, cycle-by-cycle current limit, VCC UVLO and auto-restart over-temperature protection.
For more information contact Gary de Klerk, NuVision Electronics, +27 (0)11 894 8214, [email protected], www.nuvisionelec.co.za
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