ZLED7000 Datasheet

© 2016 Integrated Device Technology, Inc.

14

April 20, 2016

Note: Silicon diodes have a greater forward voltage and overshoot caused by reverse recovery time, which can

increase the peak voltage on the LX output. Ensure that the total voltage appearing on the LX pin, including

supply ripple, is within the specified range (see Table 1.1).

3.4

Output Ripple

Shunt a capacitor CLED across the LED(s) as shown in Figure 3.1 to minimize the peak-to-peak ripple current in the

LED if necessary.

Figure 3.1

Output Ripple Reduction

Low ESR capacitors should be used because the efficiency of CLED largely depends on its ESR and the dynamic

resistance of the LED(s). For an increased number of LEDs, using the same capacitor will be more effective.

Lower ripple can be achieved with higher capacitor values, but this will increase start-up delay by reducing the

slope of the LED voltage. The capacitor will not affect operating frequency or efficiency. For a simulation or bench

optimization, CLED

values of a few μF are an applicable starting point for the given configuration.

VIN

ISENSE

LX

ZLED7000

n LED

L1

CLED

RS

D1

VS

GND

ADJ

C1