The TLC5905 is a constant current driver that incorporates shift register, data latch, constant current circuitry with a current value adjustable and 256 gray scale display that uses pulse width control. The output current can be selected as maximum 80 mA with 16 bits or 120 mA with 8 bit. The current value of the constant current output is set by one external resistor. After this device is mounted on a printed-circuit board (PCB), the brightness deviation between LED modules (ICs) can be adjusted using an external data input, and the brightness control for the panel can be accomplished by the brightness adjustment circuitry. Also, the device incorporates the output voltage monitor (OVM) used for LED open detection (LOD) by monitoring constant current output. Moreover, the device incorporates watchdog timer (WDT) circuitry, which turns constant current output off when the scan signal stops during dynamic scanning operation, and thermal shutdown (TSD) circuitry, which turns constant current output off when the junction temperature exceeds the limit.
Drive Capability and Output Counts:
80 mA (Current Sink) × 16 Bits
120 mA (Current Sink) × 8 Bits
Constant Current Output Range:
5 mA to 80 mA/10 mA to 120 mA (Selectable by MODE Terminal) ( Current Value Setting for All Output Terminals Using External Resistor and Internal Brightness Control Register)
Constant Current Accuracy ±4% (Maximum Error Between Bits)
Voltage Applied to Constant Current Output Terminals:
Minimum 0.4 V (Output Current 5 mA to 40 mA)
Minimum 0.7 V (Output Current 40 mA to 80 mA)
256 Gray Scale Display:
Pulse Width Control 256 Steps
Brightness Adjustment:
Output Current Adjustment for 32 Steps (Adjustment for Brightness Deviation Between LED Modules)
8 Steps Brightness Control by 8 Times Speed Gray Scale Control Clock (Brightness Adjustment for Panel)
Error Output Signal Check:
Check Error Output Signal Line Such as Protection Circuit When Operating
Data Output Timing Selectable:
Select Data Output Timing for Shift Register Relative to Clock
OVM (Output Voltage Monitor):
Monitor Voltage on Constant Current Output Terminals (Detect LED Disconnection and Short Circuit)
WDT (Watchdog Timer):
Turn Output Off When Scan Signal Stopped
TSD (Thermal Shut Down):
Turn Output Off When Junction Temperature Exceeds Limit
Data Input:
Clock Synchronized 1 Bit Serial Input (Shmitt-Triggered Input)
Data Output:
Clock Synchronized 1 Bit Serial Output (3-State Output)
