HBLED driver scheme based on MIC3203 design - Power Circuit - Circuit Diagram

MIC3203 step-down constant current high-brightness LED (HBLED) driver, input voltage from 4.5V to 42V, efficiency greater than 90%, LED current accuracy ± 5%, switching frequency up to 1.5MHz, mainly used in building, industrial and environmental lighting , LED lights, indicators and emergency lighting, street lighting and 12V lighting systems.

High-Brightness LED Driver Controller with High-Side Current Sense

The MIC3203 is a hysteretic, step-down, constant-current, High-Brightness LED (HB LED) driver. It provides an ideal solution for interior/exterior lighting, architectural and ambient lighting, LED bulbs, and other general illumination applications.

The MIC3203 is well suited for lighting applications requiring a wide-input voltage range.

The hysteretic control gives good supply rejection and fast response during load transients and PWM dimming. The high-side current sensing and on-chip current-sense amplifier delivers LED current with ±5% accuracy. An external high-side currentsense resistor is used to Set the output current.

The MIC3203 offers a dedicated PWM input (DIM) which enables a wide range of pulsed dimming. A high-frequency switching operation up to 1.5MHz allows the use of smaller external components minimizing space and cost. The MIC3203 offers frequency dither feature for EMI control .

The MIC3203 operates over a junction temperature from −40°C to +125°C and is available in an 8-pin SOIC package.

Main features of MIC3203:

• 4.5V to 42V input voltage range

• High efficiency (>90%)

• ±5% LED current accuracy

• MIC3203: Dither enabled for low EMI

• MIC3203-1: Dither disabled

• High-side current sense

• Dedicated dimming control input

• Hysteretic control (no compensation!)

• Up to 1.5MHz switching frequency

• Adjustable constant LED current

• Over-temperature protection

• −40°C to +125°C junction temperature range

MIC3203 application:

• Architectural, industrial, and ambient lighting

• LED bulbs

• Indicators and emergency lighting

• Street lighting

• Channel letters

• 12V lighting systems (MR-16 bulbs, under-cabinet lighting, garden/pathway lighting)


Figure 1. Block diagram of the MIC3203/MIC3203-1