EVALED7706 STMicroelectronics, EVALED7706 Datasheet - Page 34

• Manufacturer Part Number: EVALED7706
• Description: EVALUATION BOARD FOR LED7706
• Manufacturer: STMicroelectronics

Specifications of EVALED7706

• Current - Output / Channel: 30mA
• Outputs And Type: 6, Non-Isolated
• Voltage - Output: 36 V
• Features: Dimmable, Extra 5V Output
• Voltage - Input: 4.5 ~ 36 V
• Utilized Ic / Part: LED7706
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-6445

Application information
6.4.7
6.4.8
34/46
Equation 40
R
the resistor divider. For example, setting R
standard commercial value is R
The correct selection of the OVP divider (and, as consequence, the open channel detection
threshold) must take into account the shorted LED fault threshold (see
When the selected OVP threshold is too high, an undesired triggering of the shorted LED
detection circuitry may occur when a channel opens.
In fact, as explained in section 4.3.3, once a channel opens, the device reacts increasing the
output voltage and the voltage across the working current generators may reach the shorted
LED detection threshold before the open channel detection threshold.
Compensation network
For the compensation network, the suggestions provided in
In this condition, tentatively the following value of R3 and C8 (see
good choice for the loop stability:
R
C
Boost current limit
The boost current limit is set to protect the internal power switch against excessive current.
The slope compensation may reduce the programmed current limit. Hence, to take into
account this effect, as a rule of thumb, the current limit can be set as twice as much the
maximum inductor peak current (see
I
Therefore, using equation (8) and choosing I
Equation 41
BOOST, PEAK
1
3
8
can be chosen is in the order of hundreds of kilo-ohms to reduce the leakage current in
= 2.4 kΩ
= 4.7 nF
> 2.09 A
V
OUT
,
OVP
R
2
BILIM
= 22 kΩ.
=
nLED
Section 6.4.4
=
I
BOOST
1
⋅
V
= 510 kΩ leads to R
K
BOOST, PEAK
, F
B
,
PEAK
max
+
):
=
400
240
mV
= 2.5 A, R
k
Ω
=
Section 6.1
30
2
V
= 21.89 kΩ. The closest
Figure 23
BILIM
Section 5.3.4
are always valid.
will be:
) are usually a
LED7706
).