Zxld383, Application examples – Diodes ZXLD383 User Manual
Page 7
ZXLD383
ZXLD383
Document number: DS32189 Rev. 3 - 2
7 of 10
May 2010
© Diodes Incorporated
A Product Line of
Diodes Incorporated
Application Examples
Apart from the Garden Light application circuit shown on the front page of this datasheet, the ZXLD383 may be used in
many other ways. The following circuits and notes show some other possibilities and give typical performance details.
Standard operating mode
The following circuit demonstrates how few components are required to produce a light source using the ZXLD383.
Operating from a single cell, this simple circuit is suited for use in car key fobs, novelty products etc. where small size and
low cost are critical aspects.
By directly wiring the ENA pin to V
CC
, the part is permanently enabled once a power supply is provided. The ZXLD383 is
highly tolerant of supply ripple so no decoupling of V
CC
should be needed in a compactly constructed circuit. Also, the
part’s capability of operating with a V
CC
below 0.9V means that this simple circuit will make the best use of available battery
capacity.
The attached table shows the average LED currents that can be obtained using a range of inductor values. Also shown are
the peak currents required to achieve the given currents.
Notes: V
LED
= 3.5V
Low Ripple LED Current Mode
It is possible that the peak LED current required to achieve a given average current is either too high for the LED of choice
or it leads to some loss of efficiency (due to LED resistance losses). In these cases, just two extra low cost components
can be added to provide a low ripple current supply for the LED. The Schottky diode D1 and capacitor C1 rectifies and
smoothes the output of the ZXLD383 giving a low ripple current supply to the load LED. Of course, this circuit could also be
used to power loads other than LEDs.
Notes: V
LED
= 3.5V, D1 = ZHCS1000, C1 = 1µF (low ESR)
L
I
L E D
(peak)
I
L E D
(avg)
(uH )
(m A)
(m A )
47
45
8.5
22
100
17.3
10
210
34
6.8
330
50
4.7
415
63
Z XLD 383
3
2
1
4
EN A
GN D
VOU T
5
VC C
L1
1.5V
LED
N C
L
I
L E D
(uH )
(m A)
47
7.5
22
15.5
10
31
6.8
46
4.7
58
D 1
L E D
C 1
Z XL D 3 8 3
3
2
1
4
E N A
G N D
V O U T
5
V C C
L 1
1 . 5 V
N C