PFET Buck Controller for High Power LED Drives
Features
■ 2Ω, 1A Peak MosFET Gate Drive
■ VIN Range: 6V to 42V (LM3409)
■ VIN Range: 6V to 75V (LM3409HV)
■ Differential, High-side Current Sense
■ Cycle-by-Cycle Current Limit
■ No Control Loop Compensation Required
■ 10,000:1 PWM Dimming Range
■ 250:1 Analog Dimming Range
■ Supports All-Ceramic Output Capacitors and Capacitorless Outputs
■ Low Power Shutdown
■ Thermal Shutdown Protection
■ Thermally Enhanced eMSOP-10 Package
Applications
■ LED Driver
■ Constant Current Source
■ Automotive Lighting
■ General Illumination
■ Industrial Lighting
General Description
The LM3409/09HV are P-channel MosFET (PFET) controllers for
step-down (buck) current regulators. They offer wide input voltage
range, high-side differential current sense with low adjustable
threshold voltage, fast output enable/disable function and a
thermally enhanced eMSOP-10 package.
These features combine to make the LM3409/09HV ideal for use as
constant current sources for driving LEDs where forward currents up
to 5A are easily achievable. The LM3409/09HV uses Constant Off-Time
(COFT) control to regulate an accurate constant current without the
need for external control loop compensation. Analog and PWM dimming
are easy to implement and result in a highly linear dimming range
with excellent achievable contrast ratios.
Programmable UVLO, low-power shutdown, and thermal shutdown
complete the feature set.
Typical Application
