IRPLLED1 International Rectifier, IRPLLED1 Datasheet - Page 21

• 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

Although the inclusion of the resistor Rout minimizes or eliminates the load current spikes, the overall current
regulation and operating frequency will be slightly compromised. The resistor reduces the overall effectiveness of
the output capacitor, which means the switching frequency will marginally increase. The output ripple current will
also increase, which ultimately leads to a larger current regulation tolerance. Although the overall current regulation
capabilities may decrease with the inclusion of this resistor, the actual stability of the PWM dimming signal will still
be the dominant factor of the overall output current regulation capabilities.
It should be noted that the IRPLLED1 reference design board reflects the schematic of Figure 16 where a high speed
diode is used in place of the lower MOSFET switch indicated in Figure 1.
The addition of resistor RSYNC and diode DSYNC synchronizes the ENN input signal such that, when ENN
transitions from low to high to disable the oscillator during a period when HO is high, the IRS2540 will not react
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Fig. 28 Load Current Ripple Including Rout (5ohm)
Fig. 27 Load Current Spike Including Rout (5ohm)
Iout = 350mA, Vin = 100V, Vout = 17V
Iout = 350mA, Vin = 100V, Vout = 17V
RD-0608
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