LED7707 STMicroelectronics, LED7707 Datasheet - Page 33
LED7707
Manufacturer Part Number
LED7707
Description
LED Drivers 6-ROW 85mA LED DRIV BOOST REG LCD PANEL
Manufacturer
STMicroelectronics
Datasheet
1.LED7707.pdf
(47 pages)
Specifications of LED7707
High Level Output Current
85 mA
Operating Supply Voltage
4.5 V to 36 V
Maximum Supply Current
1 mA
Maximum Power Dissipation
2.3 W
Maximum Operating Temperature
+ 150 C
Mounting Style
SMD/SMT
Package / Case
VFQFPN-24
Minimum Operating Temperature
- 40 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
LED7707-3
Manufacturer:
ST
Quantity:
20 000
Company:
Part Number:
LED7707TR
Manufacturer:
ST
Quantity:
12 000
Company:
Part Number:
LED7707TR
Manufacturer:
STMicroelectronics
Quantity:
10 000
LED7707
6.4.4
Output capacitor choice
The choice of the output capacitor is mainly affected by the desired output voltage ripple.
Since the voltage across the LEDs can be considered almost constant, this ripple is
transferred across the current generators, affecting their dynamic response.
The output ripple can be estimated as (neglecting the contribution of ESR of C
in case of MLCC):
Equation 31
where I
Equation 32
whereas D, working in DCM, is:
Equation 33
defining M as:
Equation 34
Figure 21. Inductor current in DCM operation
I
L, peak
I
L, peak
L
T
ON
is the inductor peak current (see
D
T
=
SW
I
T
, L
OFF
= 1/F
peak
2
⋅
M
F
sw
SW
=
=
⋅
F
V
V
Δ
L
R
sw
IN
V
OUT
V
⋅
0
IN
M
OUT
⋅
⋅
D
L
(
M
⎧
⎨
⎩
=
. 2
. 2
=
−
⎧
⎨
⎩
015
463
) 1
. 1
(
. 1
I
, L
762
915
=
peak
⎧
⎨
⎩
@
. 0
@
2
A
A
. 0
−
Figure 21
⋅
414
I
C
55
OUT
@
V
@
OUT
V
IN
IN
,
)
,
@
max
min
@
⋅
V
V
T
IN
IN
OFF
) calculated as:
=
,
=
,
max
min
V
V
10
13
IN
IN
`
,
min
,
=
8 .
max
=
2 .
10
13
V
V
=
=
8 .
2 .
10
Application information
13
V
V
8 .
2 .
V
V
OUT
, very low
t
AM00593v1
33/47