General Description

The EC4304B is a continuous mode inductive step-down converter, designed for driving single or multiple series connected LEDs efficiently from a voltage source higher than the LED voltage. The device operates from an input supply between 7V and 36V and provides an externally adjustable output current of up to 1.2A.
Depending upon supply voltage and external components, this can provide up to 42 watts of output power.
The EC4304B includes the output switch and a highside output current sensing circuit, which uses an external resistor to set the nominal average output current.
Output current can be adjusted above, or below the set value, by applying an external control signal to the ‘ADJ’ pin.
The ADJ pin will accept either a DC voltage or a PWM waveform. Depending upon the control frequency, this will provide either a continuous or a gated output current.
The PWM filter components are contained within the chip. The EC4304B is available in SOT-23, SOT-89 Lead-free package.

FEATURES

• Wide Input Voltage Range: 7V to 36V
• LED Output Current Up to 1.2A
• Soft-start
• Single pin on/off and brightness control using DC voltage or PWM
• High efficiency (up to 97%)
• Up to 1MHz switching frequency
• Typical 5% output current accuracy
• SOT-23, SOT-89 Lead-free Package .

Applications

• LED/Display Back Light Driver
• Lightings
• Portable Communication Devices
• Handheld Electronics