Fig. shows the circuit for driving LCD seven segment y using IC 4543B.The 4543B BCD-to-7 segment latch/decoder/driver is designed for liquid crystal Pins A,
B, C and D represent BCD inputs with A as a least significant bit (LSB) as a most significant bit (MSB). Pins a through g are the seven segment outputs. It has three
control terminals LD (Latch Disable), PH (Phase), and BL (Blank). In internal use the
LD terminal is held high and BL terminal is tied low. The state of the PH terminal depends on the type of display that is being driven. For driving LCD displays, square
wave (about 60Hz swinging fully between the GND and Vcc values) must b applied to
the phase terminal.
The display can be blanked by simply driving the BL terminal to the logic high state. When the LD terminal is in its normal high state, BCD inputs are decoded and fed directly to the seven segment output terminals of the IC. When the LD terminal is pulled low, the BCD input signals that are present at the moment of transition are latched into memory and fed to the seven segment outputs.
The Fig shows how above circuit can be used to drive a 4-digit nonmultiplexed, 7-segment LCD display. Here, BCD input for each display is latched in the corresponding latch. The latch enable signals are activated using 2: 4 decoder in synchronization with the BCD inputs.
to everyone. Keep sharing this kind of articles, Thank you.HDMI Touch Screen Display suppliers
ReplyDelete