ZXLD1366EN8TC Diodes Zetex, ZXLD1366EN8TC Datasheet - Page 24

• Manufacturer Part Number: ZXLD1366EN8TC
• Description: SEMICONDUCTOR OTHER
• Manufacturer: Diodes Zetex

Specifications of ZXLD1366EN8TC

• Constant Current: *
• Constant Voltage: *
• Topology: *
• Number Of Outputs: *
• Internal Driver: *
• Type - Primary: *
• Type - Secondary: *
• Frequency: *
• Voltage - Supply: *
• Voltage - Output: *
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width) Exposed Pad
• Operating Temperature: *
• Current - Output / Channel: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: ZXLD1366EN8TCTR

A Product Line of
Diodes Incorporated
ZXLD1366
Application Information
(Continued)
Reducing output ripple
Peak to peak ripple current in the LED(s) can be reduced, if required, by shunting a capacitor Cled across the LED(s) as
shown below:
D1
V
IN
Rs
LED
Cled
L1
V
I
LX
IN
SENSE
ZXLD1366
Figure 6. Reduced Output Ripple
A value of 1µF will reduce the supply ripple current by a factor three (approx.). Proportionally lower ripple can be achieved
with higher capacitor values. Note that the capacitor will not affect operating frequency or efficiency, but it will increase start-
up delay, by reducing the rate of rise of LED voltage.
By adding this capacitor the current waveform through the LED(s) changes from a triangular ramp to a more sinusoidal
version without altering the mean current value.
Operation at low supply voltage
Below the under-voltage lockout threshold (V
) the drive to the output transistor is turned off to prevent device operation
SD
with excessive on-resistance of the output transistor. The output transistor is not full enhanced until the supply voltage
exceeds approximately 17V. At supply voltages between V
and 17V care must be taken to avoid excessive power
SD
dissipation due to the on-resistance.
Note that when driving loads of two or more LEDs, the forward drop will normally be sufficient to prevent the device from
switching below approximately 6V. This will minimize the risk of damage to the device.
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ZXLD1366
March 2011
www.diodes.com
© Diodes Incorporated
Document number: DS31992 Rev. 6 - 2