MIC3223

High Power Boost LED Driver with

Integrated FET

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com

January 2010

M9999-011510-A

General Description

The MIC3223 is a constant current boost LED driver

capable of driving a series string of high power LEDs. The

MIC3223 can be used in general lighting, bulb replacement,

garden pathway lighting and other solid state illumination

applications.

The MIC3223 is a peak current mode control PWM boost

regulator and the 4.5V and 20V operating input voltage

range allows multiple applications from a 5V or a 12V bus.

The MIC3223 implements a fixed internal 1MHz switching

frequency to allow for a reduction in the design footprint

size. Power consumption has been minimized through the

implementation of a 200mV feedback voltage that provides

an accuracy of ±5%. The MIC3223 can be dimmed through

the use of a PWM signal and features an enable pin for a

low power shutdown state.

The MIC3223 is a very robust LED driver and offers the

following protection features: over voltage protection (OVP),

thermal shutdown, switch current limiting and under voltage

lockout (UVLO).

The MIC3223 is offered in a low profile exposed pad 16-pin

TSSOP package.

Data sheets and support documentation can be found on

Micrel’s web site at: www.micrel.com.

Features

• 4.5V to 20V supply voltage

• 200mV feedback voltage with an accuracy of ±5%

• Step-up output voltage (boost) conversion up to 37V

• 1MHz switching frequency

• 100mΩ/3.5A internal power FET switch

• LEDs can be dimmed using a PWM signal

• User settable LED current (through external resistor)

• Externally programmable soft-start

• Protection features that include:

–

Output over-voltage protection (OVP)

–

Under-voltage lockout (UVLO)

–

Over temperature protection

• Junction temperature range: -40°C to +125°C

• Available in a exposed pad 16-pin TSSOP package

Applications

• Architectural lighting

• Industrial lighting

• Signage

• Landscape lighting (garden/pathway)

• Under cabinet lighting

• MR-16 bulbs

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Typical Application