Diodes ZXLD1362 - Manual (Page 6)

ZXLD1362
ZXLD1362
Document number: DS33472 Rev. 5 - 2
6 of 24
www.diodes.com
May 2012
© Diodes Incorporated
A Product Line of
Diodes Incorporated
Device Description
Switching Thresholds
With V
ADJ
= V
REF
, the ratios of R1, R2 and R3 define an
average V SENSE switching threshold of 100mV (measured on
the I
SENSE
pin with respect to V
IN
). The average output current
I
OUTnom
is then defined by this voltage and R
S
according to:
I
OUTnom
= 100mV/R
S
Nominal ripple current is ±10mV/R S
Adjusting output current
The device contains a low pass filter between the ADJ pin and
the threshold comparator and an internal current limiting
resistor (50k
Ω nom) between ADJ and the internal reference
voltage. This allows the ADJ pin to be overdriven with either
DC or pulse signals to change the V
SENSE
switching threshold
and adjust the output current.
Details of the different modes of adjusting output current are
given in the applications section.
Output Shutdown
The output of the low pass filter drives the shutdown circuit.
When the input voltage to this circuit falls below the threshold
(0.2V nom.), the internal regulator and the output switch are
turned off. The voltage reference remains powered during
shutdown to provide the bias current for the shutdown circuit.
Quiescent supply current during shutdown is nominally 60
μA
and switch leakage is below 5 μA.
Actual Operating Waveforms
V
IN
= 15V, R
S
= 0.1V, L = 100µH Normal operation.
Output Current (Ch1) and LX Voltage (Ch2)
V
IN
= 30V, R
S
= 0.1V, L = 100µH Normal Operation.
Output Current (Ch1) and LX Voltage (Ch2)
V
IN
= 60V, R
S
= 0.1V, L = 100µH Normal Operation.
Output Current (Ch1) and LX Voltage (Ch2)