Datasheet

Application information SEA05L
8/12 Doc ID 18462 Rev 1
Figure 4. Output voltage versus output current
2.2 Compensation
The voltage control transconductance operational amplifier can be fully compensated. Both
its output and negative input are directly accessible for external compensation components.
2.3 LD pin function
The device provides a unique feature that allows highly efficient driving of an LED pilot-lamp.
The main benefit of this new feature is to allow reducing the standby power consumption of
the SMPS with the LED pilot-lamp.
The LD pin is an open-drain output able to sink 5 mA (peak), driven by the internal oscillator
at 1 kHz (typ.) square waveform with 12.5% duty cycle (see Figure 6). The internal mosfet
starts to switch when V
CC
is above the turn-on threshold (typ 3 V) and it is off (LD high
impedance) when V
CC
is below the UVLO of the IC.
Connecting the LED pilot-lamp, with a resistor in series in order to limit the LED current, to
pin LD (as shown in Figure 5) reduces the power consumption of the LED while keeping the
same driving peak current. The LED driving current modulation frequency of 1 kHz (typ.)
eliminates the visual perception of flickering.
Vout
Iout
Voltage regulation
Current regulation
Vcc of the device independent from output voltage)
(
AM04987v1