tb62778fng Marktech Optoelectronics, tb62778fng Datasheet - Page 16

• Manufacturer Part Number: tb62778fng
• Description: 8-channel Constant-current Led Driver Of The 3.3-v And 5-v Power Supply Voltage Operation
• Manufacturer: Marktech Optoelectronics

Note) The output current at the error detection mode is 25% of a set current (total brightness adjustment code （ LSB ）
Error Detection Mode 2
error is detected, loads an error status code into the shift register. For OSD detection, an L-L-H-L-L sequence
must be shifted in. Immediately following the fifth Low bit, the input source of the shift register switches from the
SERIAL-IN terminal to the 8-bit parallel error status code register. An error status code is generated at least 3.5
µ s from the fifth rising edge of CLOCK after ENABLE is set Low. If any Low bit occurs thereafter, the detected
error status code is saved in the shift register. Therefore, while ENABLE is Low, serial data can not be shifted
into the TB62778FNG via the SERIAL-IN terminal. Setting ENABLE high changes the input source of the shift
register to the SERIAL-IN terminal, disables the outputs and terminates error detection. Thereupon, new serial
data is shifted into the TB62778FNG via the SERIAL-IN terminal while the error code in the shift register is
shifted out from the SERIAL-OUT terminal on the falling edge of CLOCK. TB62777FNG is over the power
dissipation when OSD detection. So please execute the OSD detection after the output is turning off.
In special mode, the TB62778FNG not only enables the outputs but also performs error detection, and if any
: minimum current setting).
Error Status Code in OSD Detection Mode
Sequence for Switching to Normal Mode
POR Characteristic
Input source of the
Only in the case of this signal sequence, it changes to the normal mode.
Data is reset(0) when the mode is changes from the specified mode to the normal mode.
V
V
OOD
OOD
shift register
2.8 Ｖ or less
≤ V
> V
ENABLE
CLOCK
ENABLE
LATCH
CLOCK
O
O
SOUT
Error Status Code
H
H
1
L
1
L
SERIAL-IN
(OSD Detection)
2
L
L
0
1
2
L
H
3
L
POR Release
H
H
3
4
L
VDD
L
H
5
L
4
L
Output Terminal State
3.5 µ s min
5
Error detection
TENTATIVE
Low level
Shorted
Normal
16
L
6
Bit
7
0.5 Ｖ or less
H
Bit
Error status code
6
H
Bit
5
SERIAL-IN
H
Bit
4
H
Bit
3
H
Bit
2
H
(Ver.0.0) 08-02-07
TB62778FNG