EVALED7706 STMicroelectronics, EVALED7706 Datasheet - Page 22

• 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

Operation description
5.3.3
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Open LED fault
In case a row is not connected or a LED fails open, the device has two different behaviors
according to the MODE pin status.
Connecting the MODE pin to SGND, as soon as an open row is detected the FAULT pin is
tied low and the device is turned off. The internal logic latches this status: to restore the
normal operation, the device must be restarted by toggling the EN pin or performing a
Power-On Reset (POR occurs when the voltage at the LDO5 pin falls below the lower UVLO
threshold and subsequently rises above the upper one).
If the MODE pin is high (i.e. connected to AVCC), the LED7706 behaves in a different
manner: the open row is excluded from the control loop and the device continues to work
properly with the remaining rows. The FAULT pin is not affected. Thus, if less than six rows
are used in the application, the MODE pin must be set high.
Figure 15
AVCC.
At the point marked as “1” in
point on the output voltage is increased as long as the output voltage reaches the floating
row detection threshold (see
faulty row is disconnected and the device keeps on working only with the remaining rows.
Figure 15. Open channel detection (MODE to AVCC)
shows an example of open channel detection in case of MODE connected to
Figure 15
Section 5.1.3 on page 13
, the row opens (row current drops to zero). From this
). Then (point marked as “2”) the
1
1
2
2
LED7706