UCS1903 Просмотр технического описания (PDF) - Unspecified

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UCS1903

3-Channel LED Driver / Controller

Unspecified 

UCS1903

SWITCHING CHARACTERISTICS (TA =−20 to +70℃, VDD =4.5 to 5.5V, VSS =0V, unless

otherwise specified)

Parameter

Oscillation frequency

Symbol Min.

FOSC1

-

FOSC2

-

Propagation delay time tPLZ

-

Fall time

Data transfer rate

Input capacitance

tTHZ

-

FMAX

400

CI

-

Typ.

400

800

-

-

-

-

Max

-

-

300

120

-

15

Unit

Test conditions

kHz

-

kHz

-

ns

CL =15pF, DIN→DOUT,

RL =10kΩ

μs

CL =300pF, OUTR/OUTG/

OUTB

kbps

50% duty cycle

pF

-

FUNCTIONAL DESCRIPTION

The UCS1903 sends signals in return to zero codes with a single-wire communication method.

When the power-on reset is completed, the UCS1903 receives the data from the DIN pin. When

all the 24 bits of data have been received, the DOUT port starts to forward the data to the next

chip as its input data. The DOUT pin is held LOW before the data forwarding, and the chip does

not receive new data. The three PWM output ports, OUTR, OUTG and OUTB, send signals

in a 4-ms period, with different duty cycles corresponding to the 24-bit data received. If the

input signal from the DIN pin is a RESET signal, the UCS1903 will send the received data for

display. When the signal is completed, the UCS1903 will receive new data. When all the initial

24 bits of data have been received, the UCS1903 will forward the data through the DOUT pin.

Before the RESET signal is received, the output at the OUTR, OUTG and OUTB pins will remain

unchanged. When a low level RESET code longer than 24µs is received, the UCS1903 will

output the 24-bit PWM data just received to the OUTR, OUTG and OUTB pins.

The UCS1903 employs an automatic shaping-forwarding technique, so the number of the

cascaded chips is not limited by the signal transfer, and is only limited by the panel refresh

speed. For example, in a 1024-chip cascaded design with the panel refresh time of 1024X0.4X2

=0.8192ms (the data delay time of the UCS1903 is 0.4µs), no flickering will appear.

V. 1.0

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