Zetex Semiconductors PLC zxld1350ev2 manual Performance, Efficiency vs supply voltage

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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

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Contents ZXLD1350EV2 DescriptionZXLD1350 Device Features Device Applications ZXLD1350 Device DescriptionOrdering Information Evalboard Order Number Device Order NumberZXLD1350 Operation Schematic DiagramZXLD1350EV2 Evaluation Board Reference Design NIC NPIS53D101MTRF NICSD1 SOT23 ZXLD1350EV2 Power Up ZXLD1350EV2 Connection Point Definition Name Description +VIN ZXDL1350EV2 OperationOther Features DimmingDC Voltage Dimming High Frequency PWM DimmingSwitching the output current off Using external LEDs or loadsLow Frequency PWM Dimming Soft-startPerformance Efficiency vs supply voltageDefinitions