IRPLLED1 International Rectifier, IRPLLED1 Datasheet - Page 9

• 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

The output capacitor can be used simultaneously to reduce the frequency and improve current control accuracy. Fig.
11 shows how the capacitance reduces the frequency over a range of input voltage. A small capacitance of 4.7uF has
a large effect on reducing the frequency. Fig. 12 shows how the current regulation is also improved with the output
capacitance. There is a point at which continuing to add capacitance no longer has a significant effect on the
operating frequency or current regulation, as can be seen in Fig. 12 and Fig. 13.
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1000
100
390
380
370
360
350
340
330
10
30
30
Fig. 11 Iout = 350mA, Vout = 16.8V, L = 470uH
Fig. 12 Iout = 350mA, Vout = 16.8V, L = 470uH
50
70
RD-0608
80
90
Vin (V)
Vin (V)
110
130
130
150
170
0uF
4.7uF
10uF
22uF
33uF
47uF
0uF
4.7uF
10uF
22uF
33uF
47uF
180
9