ZXLD1350EV2

PERFORMANCE

The system efficiency depends on the sense resistor, supply voltage, switching inductor and the number of 1W LEDs connected in series.

The graph below shows the efficiency with a 0.33Ω sense resistor RS, and a 100uH inductor, for 1 to 3 series connected 1W LEDs.

With a 24V supply, the switching frequency is typically 545kHz for three series-connected 1-watt LEDs and 300kHz for a single 1-watt LED.

With a 12V supply, the switching frequency is typically 160kHz for three series-connected 1-watt LEDs and 280kHz for a single 1-watt LED

The detailed performance information for the device can be found in the datasheets.

 

 

 

Efficiency vs Vin

 

 

 

 

 

Rsense=0.33 Ohms, L=100uH (NIC NPIS53D101MTRF)

 

95

 

 

 

 

 

 

 

90

 

 

 

 

 

 

 

Eff (%)

 

 

 

 

 

 

1 LED

 

 

 

 

 

 

 

85

 

 

 

 

 

 

2 LED

 

 

 

 

 

 

 

3 LED

80

 

 

 

 

 

 

 

75

 

 

 

 

 

 

 

0

5

10

15

20

25

30

35

 

 

 

 

Vin (V)

 

 

 

Figure 6: Efficiency vs supply voltage

ZXLD1350EV2 User Guide Iss 5

10-04-07

Page 8
Image 8
Zetex Semiconductors PLC zxld1350ev2 manual Performance, Efficiency vs supply voltage