MIC3203/MIC3203-1

High-Brightness LED Driver Controller

with High-Side Current Sense

General Description

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 current-

sense 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.

A dither disabled version MIC3203-1 is also available in

the same package as the MIC3203.

Datasheets and support documentation can be found on

Micrel’s web site at: www.micrel.com.

Features

• 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

Applications

• 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)

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Typical Application

MIC3203 Step-down LED Driver

March 2010

M9999-032910-A