STEVAL-ILL021V1 STMicroelectronics, STEVAL-ILL021V1 Datasheet - Page 37

• Manufacturer Part Number: STEVAL-ILL021V1
• Description: BOARD EVAL LCD BACKLIGHT LED7707
• Manufacturer: STMicroelectronics

Specifications of STEVAL-ILL021V1

• Design Resources: STEVAL-ILL021V1 Bill of Material STEVAL-ILL021V1 Schematic
• Current - Output / Channel: 85mA
• Outputs And Type: 6, Non-Isolated
• Voltage - Output: 36 V
• Features: Dimmable, Extra 5V Output
• Voltage - Input: 4.5 ~ 36 V
• Utilized Ic / Part: LED7707
• Description/function: LCD backlight demonstration board
• Operating Voltage: 4.5 V to 36 V
• Product: Display Modules
• Core Chip: LED7707
• No. Of Outputs: 1
• Output Voltage: 36V
• Dimming Control Type: PWM
• Mcu Supported Families: LED7707
• Lead Free Status / RoHS Status: Lead free by exemption / RoHS compliant by exemption
• For Use With/related Products: LED7707
• Other names: 497-10044

LED7707
Note:
In order to estimate also the efficiency, other contributions to the power dissipation must be
added to P
Equation 47
where V
Equation 48
where DCR = 80 mΩ (typical DCR of the recommended inductors).
Therefore the total dissipated power is:
Equation 49
Considering the input power as the result of input voltage multiplied by the input current, the
estimated efficiency is:
Equation 50
It is important to remind that the previous calculations consider the worst case, especially for
the power dissipated on the current generators.
Statistical analysis (confirmed by bench measurements) shows that the series connection of
more LEDs on each channel leads to compensation effects.
The hypothesis 3 above mentioned is thus rather unlikely.
Therefore P
F, Diode
D, tot
GEN
= 0.4 V
(which represents only the power dissipated by the device), that is:
is significantly lower and the overall efficiency is typically around 90 %.
P
DISS
P
DISS
,
TOTAL
P
DISS
,
Ind
=
,
Diode
η
=
P
DCR
=
, D
P
tot
=
IN
+
V
⋅
−
I
, F
P
2
Ind
P
P
Diode
DISS
DISS
,
IN
RMS
,
Diode
,
⋅
TOT
I
≅
IN
DCR
⋅
+
D
=
P
2
. 0
DISS
=
⋅
862
I
2
IN
133
,
Ind
=
mW
63
=
. 1
mW
316
Application information
W
37/47