LED7706 STMicroelectronics, LED7706 Datasheet - Page 17

• Manufacturer Part Number: LED7706
• Description: IC LED DRIVR WHT BCKLT 24-VFQFPN
• Manufacturer: STMicroelectronics
• Type: Backlight, White LEDr

Specifications of LED7706

• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 6
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: 250kHz ~ 1MHz
• Voltage - Supply: 4.5 V ~ 36 V
• Voltage - Output: 36V
• Mounting Type: Surface Mount
• Package / Case: 24-VFQFN, 24-VFQFPN
• Current - Output / Channel: 30mA
• Internal Switch(s): Yes
• Operating Supply Voltage: 4.5 V to 36 V
• Maximum Supply Current: 1 mA
• Maximum Power Dissipation: 2300 mW
• Maximum Operating Temperature: + 150 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• For Use With: 497-10043 - BOARD EVAL LCD BACKLIGHT LED7706497-8360 - BOARD EVAL FOR LED7707497-6445 - EVALUATION BOARD FOR LED7706
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Operating Temperature: -
• Efficiency: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

LED7706
The SLOPE pin allows to properly set the amount of slope compensation connecting a
simple resistor R
starts at 35% (typ.) of each switching period and its slope is given by the following equation:
Equation 6
Where KS = 5.8
To avoid sub-harmonic instability, the compensating slope should be at least half the slope
of the inductor current during the off-phase when the duty-cycle is greater than 50%. The
value of R
Equation 7
Figure 12. Effect of slope compensation on small inductor current perturbation
SLOPE
Inductor current (CCM)
Inductor current (CCM)
(D > 0.5)
0.35
0.35
⋅
can be calculated according to equation 7.
SLOPE
10
·T
·T
ΔI
ΔI
SW
SW
10
L
L
s
between the SLOPE pin and the output. The compensation ramp
T
T
-1
Inductor current
Inductor current
perturbation
perturbation
SW
SW
, V
R
BE
SLOPE
= 2 V (typ.) and S
S
E
≤
=
slope compensation (S
slope compensation (S
Programmed inductor peak current with
Programmed inductor peak current with
2
K
⋅
S
K
⎛
⎜
⎜
⎝
S
V
⋅
OUT
L
V (
I
I
⋅
BOOST, PEAK
BOOST, PEAK
R
V (
OUT
−
SLOPE
OUT
E
V
IN
is the slope ramp in [A/s].
−
−
−
V
E
E
)
)
IN
V
V
BE
IN
)
−
⎞
⎟
⎟
⎠
V
BE
)
Operation description
t
t
AM00606v1
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