BL55024
zip: 200233
Shanghai Belling Corp., Ltd
Tel: 86-021-64850700 Fax: 86-021-64855865
LCD Driver for 60 Display Units
BL55024
1
General Description
The BL55024 is a general LCD driver IC for 60 units LCD panel. It features a wide
operating supply voltage range, incorporates simple communication interface with
microcomputer and is suitable for multiple application.
2
Features
Advanced low power CMOS Technology
Selection of 1/2 or 1/3 bias, selection of 1/2 or 1/3 or 1/4 duty.
Operation voltage: 2.5~5.5V
Serial data interface
60(15x4) Display Units
Low power dissipation design: Power saving mode: Idd=14uA at 5V and Idd=9uA at
3.3V;
On-chip RC oscillator
VLCD for adjusting LCD operating voltage
Excellent EMC immunity
Compatible with general microcomputer
SOP24 package
3
Pin Assignment
Fig 1
4
Pin Description
Pin No.
1
2
3
4
5
6-9
10-24
Pin name
SDA
SCI
Vdd
Vss
Vlcd
Com0、Com2、Com1、Com3
S0——S14
Function
Serial data input/output
Serial clock input
Supply voltage
ground
LCD supply voltage
Common terminal driving output
Segment terminal driving output
Tab.1
1
BL55024
zip: 200233
Shanghai Belling Corp., Ltd
Tel: 86-021-64850700 Fax: 86-021-64855865
5
Function Description
1.function circuit
The BL550024 has all function circuits that can directly drive any static or multiplexed LCD
containing up to four commons and up to 15 segments. The function circuits include:Power-on
reset, LCD bias generator, LCD voltage selector, Oscillator, display RAM, Timing, Display latch,
Shift register, Common/segment outputs, input/output bank selector, Blinker, Data pointer, etc.
2.display function decription
The display RAM is a static 15x 4-bit RAM which stores LCD data. A logic 1 in the
RAM bit-map indicates the on state of the corresponding LCD segment; similarly, a logic 0
indicates the off state. There is a one-to-one correspondence between the RAM addresses and
the segment outputs, and between the individual bits of a RAM word and the common
outputs. (see Fig.2).
Display RAM address and SEGMENT（S0~S14）output
（
）
0
COM
(Com0~
Com3)
输出
0
1
2
3
1
2
3
。
。
。
。
11
12
13
14
Fig2
When display data is transmitted to the BL55024, the display bytes received are stored
in the display RAM in accordance with the selected LCD drive mode. To illustrate the filling
order, an example of a 7-segment numeric display showing all drive modes is given in Fig.3;
the RAM filling organization depicted applies equally to other LCD types.
Fig 3
2
BL55024
zip: 200233
2
3. I C-bus protocol
I
2
C-bus slave addresses (0111110) are reserved for the BL55024
The I2C-bus protocol is shown in Fig.4. The sequence is initiated with a START
condition (S) from the I2C-bus master which is followed by the BL55024 slave addresses
available. After acknowledgement, one or more command bytes (m) follow which define the
status of the addressed BL55024. The last command byte is tagged with a cleared most
significant bit, the continuation bit C. The command bytes are also acknowledged by the
addressed BL55024 on the bus. After the last command byte, a series of display data bytes(n)
may follow. These display bytes are stored in the display RAM at the address specified by the
data pointer. Data pointer are automatically updated and the data is directed to the intended
BL55024 device. After the last display byte, the I2C-bus master issues a STOP condition (P).
Shanghai Belling Corp., Ltd
Tel: 86-021-64850700 Fax: 86-021-64855865
Fig 4
4. command decoder
The command decoder identifies command bytes that arrive on the I
2
C-bus. All
available commands carry a continuation bit C in their most significant bit position. The four
commands available to the BL55024 are defined in Fig 5.
3
BL55024
zip: 200233
Shanghai Belling Corp., Ltd
Tel: 86-021-64850700 Fax: 86-021-64855865
Fig 5
6
Absolute Maximum Rating
Parameter
Symbol
Vdd
Vlcd
Vi
Vo
Idd,Iss,Ilcd
Ptot
Topr
Tstg
Rating
-0.5½+6.0
0½ Vdd
Vss-0.5½Vdd+0.5
Vlcd-0.5½Vdd+0.5
-50½+50
400
-40½ +75
-65½ +150
Unit
V
V
V
V
mA
mW
o
C
o
C
Supply voltage
LCD operating voltage
Input voltage
Output voltage
Vdd,Vss,Vlcd current
Maximum power consumption
Operating temperature
Storage temperature
7
Vdd
Vlcd
Idd1
Idd2
Idd3
Idd4
ViL
ViH
DC Characteristic
Test Condition
Min
2.5
0
Vdd=5V,VLCD=0V,Normal
mode,internal oscillator
Vdd=5V,VLCD=0V,power saving
mode,internal oscillator
Vdd=3.3V,VLCD=0V,Normal
mode,internal oscillator
Vdd=3.3V,VLCD=0V,power saving
mode,internal oscillator
Symbol Parameter
IC Operating
voltage
LCD operating
voltage
Supply current
Supply current
Supply current
Supply current
Low voltage input
High voltage
input
Typ
-
-
25
14
16
9
-
-
Max
5.5
Vdd-2
50
30
30
15
0.3Vdd
6.0
Unit
V
V
uA
uA
uA
uA
V
V
-
-
-
-
Vss
0.7Vdd
SDA,SCL
SDA,SCL
4
BL55024
zip: 200233
Shanghai Belling Corp., Ltd
Tel: 86-021-64850700 Fax: 86-021-64855865
8
Fclk
Fclk
Tclk
Tsh1
Tsh2
tlow
thig
thd
AC Characteristic
Test Condition
Vdd=5V,normal mode
Vdd=3.3V, power saving
mode
Ta=25
o
C
Min
125
21
1
5
5
5
4
250
Symbol Parameter
Oscillator
frequency
Oscillator
frequency
Half oscillator cycle
CS start hold time
SCL start hold time
High time
Low time
SCL hold time
Typ
180
31
-
-
-
-
-
Max
300
48
3
Unit
KHz
KHz
uA
us
us
us
us
ns
Fig 6
9
Typical Application Circuit
No
te:
1/ when I
2
C are idle mode,SDA and SCL must be connect to high level(by pull up
resistor),otherwise the device maybe can not go into power saving mode.
2/
3/
In power-saving mode, SCL frequency must be less than 21KHz.
Work at
1/3 bias, Vdd – Vlcd must be more than 2.9V。
。
Fig 7
5
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