The LM3409HVEVAL evaluation board showcases the LM3409HV PFET controller for a buck current regulator. It is designed to drive 12 LEDs (VO = 42V) at a maximum average LED current (ILED = 1.5A) from a DC input voltage (VIN = 48V). The switching frequency (Fsw = 400kHz) is targeted for the nominal operating point, however Fsw varies across the entire operating range. However, if the input voltage drops below the regulated LED string voltage, the converter goes into dropout and VO = VIN ideally. The evaluation board showcases all features of the LM3409HV including analog dimming using the IADJ pin and internal PWM dimming using the EN pin. High frequency external parallel FET shunt PWM dimming can also be evaluated. The board has a header (J1) with a removable jumper, which is used to select the PWM dimming method.
6V to 75V input voltage range
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 capacitor less outputs
