POWER AND LINEAR IC SOLUTIONS

Ultra Compact High Brightness LED Driver

The new Micrel MIC2298 and MIC2299 are powerful LED drivers delivering a minimum power of 7W and guaranteed 3.5A current. The 2MHz MIC2299 is believed to be the industry’s smallest and most powerful such device; both converters are suitable for portable applications such as mobile phones, LED torches and digital cameras.

The drivers are high power, boost switching regulators that feature an integrated 3.5A guaranteed switch current and deliver a minimum net output power of 7W from a 3mm x 3mm footprint.

Optimised for constant current control, the devices are capable of delivering at least 1A into two white LEDs or 750mA into three LEDs connected in series. This makes them ideal for photoflash and LED torch applications. Feedback voltage is only 200mV, minimising power dissipation in constant current control applications, and hence maximising battery life. Extended battery life is supported further thanks to an ultra-low 1µA shutdown current.

LED brightness can be dynamically controlled by applying a voltage or PWM signal to the driver's brightness pin. This allows for a programmable torch mode as well as single-pin full flash control when driving high current LEDs. A 2.5V to 10V input voltage range allows direct operation from one- and two-cell Li-Ion batteries as well as three- to four-cell NiCad/NiMH/alkaline or lithium batteries.



The MIC2298 and MIC2299 implement a constant frequency PWM control scheme at 1MHz and 2MHz respectively, to ensure the smallest possible designs. The MIC2299’s 2MHz operation avoids signal interference in the AM band.

The devices are available in low profile 12-pin 3mm x 3mm MLF® packages and require only the addition of a low profile inductor and small ceramic capacitors to deliver a compact, low component count LED driver solution.

Features

• Programmable current control
• 200mV ± 10% feedback voltage
• 2.5V to 10V input voltage
• Output OverVoltage Protection (OVP)
• Output voltage up to 30V (max)
• Choice of 1MHz or 2MHz fixed frequency operation
• Guaranteed 3.5A switch current over-temperature
• Solution size of just 1.6cm² (MIC2299)
• Output power range: 7W - 12W
• <1% line regulation
• 1µA shutdown current
• Over-temperature protection
• Externally programmable soft-start
• Under-Voltage LockOut (UVLO)
• 12-pin 3mm x 3mm leadless MLF® package
• –40°C to +125°C junction temperature range

Applications

• Mobile phones
• PDAs
• Digital cameras
• LED torches

For further information, including a copy of the MIC2299 Datasheet, please click here