LED7707TR STMicroelectronics, LED7707TR Datasheet - Page 24

• Manufacturer Part Number: LED7707TR
• Description: IC LED DRIVR WHT BCKLT 24-VFQFPN
• Manufacturer: STMicroelectronics
• Type: Backlight, White LEDr

Specifications of LED7707TR

• 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
• Operating Temperature: 0°C ~ 85°C
• Current - Output / Channel: 85mA
• Internal Switch(s): Yes
• 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
• Minimum Operating Temperature: - 40 C
• For Use With: 497-10044 - BOARD EVAL LCD BACKLIGHT LED7707
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Efficiency: -
• Lead Free Status / Rohs Status: Details
• Other names: 497-8492-2

Operation description
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At the point marked as “1” in
across the current generator of the channel where the failed LED is connected increases by
an amount equal to the forward voltage of the faulty LED. Since the voltage across the
current generator is above the threshold (4 V), the device is turned off and the fault pin is set
low (point “2”). Note that, once a new dimming cycle starts (point “3”), the device waits the
masking time (approximately 100 μs) and then sets the FAULT pin low and turns off.
Figure 17. Shorted LED detection (MODE to GND)
Figure 17
masking time
masking time
1
1 1
one LED fails becoming a short-circuit. The voltage
3
3 3
2
2 2
LED7707