EC4304B Datasheet, PDF (1/11 Pages) E-CMOS Corporation – PWM Control 1.2A Step-Down Converter

PWM Control 1.2A Step-Down Converter EC4304B
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
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 high-
side 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.
PART NUMBER EXAMPLES
PART NO.
EC4304BNB2R
EC4304BNB6R
PACKAGE
SOT-23-5
SOT-89-5
PIN ARRANGEMENT(Top view)
EC4304BNB2R
SOT-23-5
E-CMOS Corp. (www.ecmos.com.tw)
Page 1 of 11
EC4304BNB6R
SOT-89-5
2011/10/06