zxld1366 Zetex Semiconductors plc., zxld1366 Datasheet - Page 27

• Manufacturer Part Number: zxld1366
• Description: High Accuracy 1a, 60v Led Driver With Internal Switch
• Manufacturer: Zetex Semiconductors plc.

Note that the device power dissipation will most often be a maximum at minimum supply
voltage. It will also increase if the efficiency of the circuit is low. This may result from the use of
unsuitable coils, or excessive parasitic output capacitance on the switch output.
Thermal compensation of output current
High luminance LEDs often need to be supplied with a temperature compensated current in order
to maintain stable and reliable operation at all drive levels. The LEDs are usually mounted
remotely from the device so, for this reason, the temperature coefficients of the internal circuits
for the ZXLD1366 have been optimized to minimize the change in output current when no
compensation is employed. If output current compensation is required, it is possible to use an
external temperature sensing network - normally using Negative Temperature Coefficient (NTC)
thermistors and/or diodes, mounted very close to the LED(s). The output of the sensing network
can be used to drive the ADJ pin in order to reduce output current with increasing temperature.
Issue 2 - September 2008
© Diodes Incorporated 2008
2000
1800
1600
1400
1200
1000
800
400
200
600
0
-50
-30
-10
Maximum Power Dissipation
10
TSOT
Ambient Temperature (Deg C)
30
DFN
27
50
70
90
110
130
150
ZXLD1366
www.diodes.com
www.zetex.com