IRPLLED1A International Rectifier, IRPLLED1A Datasheet - Page 4

• Manufacturer Part Number: IRPLLED1A
• Description: Power Management IC Development Tools Hi-Vlt DC-DC Buck Cnvr HBLED Cur Cntrl
• Manufacturer: International Rectifier
• Type: DC/DC Converters, Regulators & Controllersr

Specifications of IRPLLED1A

• Product: Power Management Development Tools
• Tool Is For Evaluation Of: IRS25401PBF
• Output Voltage: 16 V to 24 V
• Output Current: 350 mA to 1.5 A
• Factory Pack Quantity: 1

delay t_LO_off and HO switches high after the delay t_HO_on. The cycle then repeats continuously at a frequency
depending on the load current and the values of the output inductor and capacitor.
Fig. 3 IRS25401/11 Control Signals, Iavg=1.2A
The switching continues to regulate the current at an average value determined as follows: when the output
combination of L1 and COUT is large enough to maintain a low ripple on IFB (less than 100mV), Iout(avg) can be
calculated:
Having load current programmable from 350mA to 1.5A, series and parallel combinations of resistors must be used
to correctly set the current as well as distribute power accordingly. Equivalent resistances for each current setting
are calculated as follows:
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Iout
R
R
350
700
mA
mA
(
avg
=
=
350
700
)
0
0
5 .
5 .
=
mA
mA
V
V
VIFBTH
=
=
. 1
. 0
43
71
Ω
Ω
RCS
(A)
(B) Releasing Stored Inductor Energy
Fig. 2 (A) Storing Energy in Inductor
RD-0608
IFB
HO
Fig. 4 IRS25401/11 Time Delayed Hysteresis
LO
IFBTH
50%
t_HO_off
t_LO_on
50%
DT1
50%
(B)
t_LO_off
t_HO_on
50%
50%
DT2
4