IRPLLED1 International Rectifier, IRPLLED1 Datasheet - Page 4

• Manufacturer Part Number: IRPLLED1
• Description: BOARD EVALUATION FOR IRS2540PBF
• Manufacturer: International Rectifier

Specifications of IRPLLED1

• Current - Output / Channel: 1.5A
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 24V
• Features: Dimmable
• Voltage - Input: 50 ~ 170V
• Utilized Ic / Part: IRS2540PBF
• Core Chip: IRS2540, IRS2541, IRS25401
• Topology: Buck (Step Down)
• No. Of Outputs: 1
• Output Current: 1.5A
• Output Voltage: 500mV
• Dimming Control Type: PWM
• Development Tool Type: Hardware - Eval/Demo Board
• Lead Free Status / RoHS Status: Contains lead / RoHS compliant by exemption

Fig. 3 IRS2540/1 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:
www.irf.com
Iout
R
R
R
R
1
1
350
700
5 .
A
A
mA
mA
=
(
=
avg
0
1
=
=
5 .
1
0
A
5 .
5 .
V
350
700
)
0
0
V
A
5 .
5 .
=
=
mA
mA
=
V
V
0
VIFBTH
5 .
. 0
Ω
33
=
=
. 1
. 0
Ω
43
71
Ω
Ω
RCS
(A)
(B) Releasing Stored Inductor Energy
Fig. 2 (A) Storing Energy in Inductor
RD-0608
Fig. 4 IRS2540/1 Time Delayed Hysterisis
IFB
HO
LO
IFBTH
50%
t_HO_off
t_LO_on
50%
DT1
50%
(B)
t_LO_off
t_HO_on
50%
50%
DT2
4