Macroblock
Datasheet
MBI5171
8-Bit Constant Current LED Driver with
LED Error Detection and Run-Time Current Adjustment
Features
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Compatible with MBI5168 in electrical characteristics and package
Exploiting
Share-I-O™
technique to provide two operation modes:
- Normal Mode with the same functionality as MB5168
- Special Mode to detect individual LED errors, like MBI5169
and program output current gain, like MBI5170
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8 constant-current output channels
Constant output current invariant to load voltage change
Constant output current range: 5 -120 mA
Excellent output current accuracy,
between channels: <
±3%
(max.), and
between ICs: <
±6%
(max.)
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Output current adjusted through an external resistor
Fast response of output current,
OE (min.): 200 ns @I
out
< 60mA
OE (min.): 400 ns @I
out
= 60~100mA
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25MHz clock frequency
Schmitt trigger input
MBI5168CP
SOP16-300-1.27 Weight：0.37g
SOP16-150-1.27 Weight：0.13g
P-DIP16-300-2.54 Weight：1.02g
M B
MBI5168CN
N
I5 0 0 1
MBI5171CN
C
MBI5001CN
MBI5001CD
MBI5171CD
MBI5168CD
MBI5171CDW
MBI5168CDW
MBI5001CD
3.3~ 5V supply voltage
256-step run-time programmable output current gain
suitable for white balance application
MBI5171CP
SSOP16-150-0.64 Weight：0.07g
Current Accuracy
Between Channels
<
±3%
Between ICs
<
±6%
Conditions
I
OUT
= 10 ~ 100 mA,
V
DS
= 0.8V, V
DD
= 5.0V
©Macroblock,
Inc. 2004
Floor 6-4, No.18, Pu-Ting Rd., Hsinchu, Taiwan 30077, ROC.
TEL: +886-3-579-0068, FAX: +886-3-579-7534, E-mail:
info@mblock.com.tw
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August 2004, VA.00
MBI5171
Product Description
8-Bit Constant Current LED Driver with
LED Error Detection and Run-Time Current Adjustment
MBI5171 succeeds MBI5168 and also exploits
PrecisionDrive™
technology to enhance its output characteristics.
Furthermore, MBI5171 uses the idea of
Share-I-O™
technology to make MBI5171 backward compatible with
MBI5168 in both package and electrical characteristics and extend its functionality for LED load Error Detection
and run-time LED current gain control in LED display systems, especially LED traffic sign applications.
MBI5171 contains an 8-bit Shift Register and an 8-bit Output Latch, which convert serial input data into parallel
output format. At MBI5171 output stages, eight regulated current ports are designed to provide uniform and
constant current sinks with small skew between ports for driving LED’s within a wide range of forward voltage (Vf)
variations. Users may adjust the output current from 5 mA to 120 mA with an external resistor R
ext
, which gives
users flexibility in controlling the light intensity of LED’s. MBI5171 guarantees to endure maximum 17V at the
output ports. Besides, the high clock frequency up to 25 MHz also satisfies the system requirements of high
volume data transmission.
MBI5171 extends its functionality to provide one Special Mode in which two functions are included, Error Detection
and Current Gain Control, by means of the
Share-I-O™
technique on pins LE and
OE
, without any extra pins.
Thus, MBI5171 could be a drop-in replacement of MBI5168. The printed circuit board originally designed for
MBI5168 may be also applied to MBI5171. In MBI5171 there are two operation modes and three phases: Normal
Mode phase, Mode Switching transition phase, and Special Mode phase. The signal on the multiple function pin
OE / SW / ED would be monitored. Once an one-clock-wide short pulse appears on the pin OE / SW / ED ,
MBI5171 would enter the Mode Switching phase. At this moment, the voltage level on the pin LE/MOD/CA is used
for determining the next mode to which MBI5171 is going to switch.
In the Normal Mode phase, MBI5171 has exactly the same functionality with MBI5168. The serial data could be
transferred into MBI5171 via the pin SDI, shifted in the Shift Register, and go out via the pin SDO. The LE/MOD/CA
can latch the serial data in the Shift Register to the Output Latch. OE / SW / ED would enable the output drivers to
sink current.
In the Special Mode phase, the low-voltage-level signal OE / SW / ED can enable output channels and detect the
status of the output current to tell if the driving current level is enough or not. The detected error status would be
loaded into the 8-bit Shift Register and be shifted out via the pin SDO along with the signal CLK. Then system
controller could read the error status and know whether the LED’s are properly lit or not.
On the other hand, in the Special Mode phase MBI5171 also allows users to adjust the output current level by
setting a run-time programmable Configuration Code. The code is sent into MBI5171 via the pin SDI. The positive
pulse of LE/MOD/CA would latch the code in the Shift Register into a built-in 8-bit Configuration Latch, instead of
the Output Latch. The code would affect the voltage at the terminal R-EXT and control the output current regulator.
The output current could be adjusted finely by a gain ranging (1/12) to (127/128) in 256 steps. Hence, the current
skew between IC’s can be compensated within less than 1% and this feature is suitable for white balancing in LED
color display panels.
Users can get detailed ideas about how MBI5171 works in the section
Operation Principle.
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August 2004, VA.00
MBI5171
Pin Assignment
GND
SDI
CLK
LE/MOD/CA
OUT 0
OUT1
OUT2
OUT3
1
2
3
4
5
6
7
8
8-Bit Constant Current LED Driver with
LED Error Detection and Run-Time Current Adjustment
16
15
14
13
12
11
10
9
VDD
R-EXT
SDO
OE/SW/ED
OUT7
OUT6
OUT5
OUT4
Terminal Description
Pin No.
1
2
3
Pin Name
GND
SDI
CLK
Function
Ground terminal for control logic and current sinks
Serial-data input to the Shift Register
Clock input terminal for data shift at the rising edge
Output channel data strobe input terminal:
in the Normal Mode phase, serial
data in the Shift Register is transferred to the respective Output Latch when
LE/MOD/CA is high; the data is latched inside the Output Latch when LE/MOD/CA
goes low. If the data in the Output Latch is
“1”
(High), the respective output channel
will be enabled after OE / SW / ED is pulled down to low.
Mode selection input terminal:
in the Mode Switching phase, LE/MOD/CA
couldn’t strobe serial data but its level is used for determining the next mode to
which MBI5171 is going to switch. When LE/MOD/CA is high, the next mode is the
Special Mode; when low, the next mode is the Normal Mode.
Configuration data strobe input terminal:
in the Special Mode phase, serial data
is latched into the Configuration Latch, instead of the Output Latch in the Normal
Mode. The serial data here is regarded as the Configuration Code, which affect the
output current level of all channels.(See
Operation Principle)
Constant current output terminals
Output enable terminal:
no matter in what phase MBI5171 operates, the signal
OE / SW / ED can always enable output drivers to sink current. When its level is
(active) low, the output drivers are enabled; when high, all output drivers are turned
OFF (blanked).
Mode switching trigger terminal:
an one-clock-wide short pulse signal of
OE / SW / ED could put MBI5171 into the Mode Switching phase.
Error detection enable terminal:
in the Special Mode phase, the active low signal
OE / SW / ED can make MBI5171 not just enable output drivers but detect LED
load error status. The detected error status would be stored into the Shift Register.
(See
Operation Principle)
Serial-data output to the following SDI of the next driver IC
Input terminal used for connecting an external resistor in order to set up the current
level of all output ports
Supply voltage terminal
4
LE/MOD/CA
5-12
OUT0 ~ OUT7
13
OE / SW / ED
14
15
16
SDO
R-EXT
VDD
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August 2004, VA.00
MBI5171
Pin
No.
Pin Name
Function
8-Bit Constant Current LED Driver with
LED Error Detection and Run-Time Current Adjustment
Normal
Mode
Yes
No
No
Yes
Yes
Mode
Switching
No
Yes
No
Yes
Yes
Special
Mode
No
No
Yes
Yes
Yes
In MBI5171, the relationship between the functions of pins 4 and 13 and the operation phases are listed below:
LE: latching serial data into the
Output Latch
4
LE/MOD/CA
MOD: mode selection
CA: latching serial data into the
Configuration Latch
OE : enabling the current output
drivers
13
OE / SW / ED
SW: entering the Mode Switching
phase
ED : enabling error detection and
storing results into the Shift
Register
No
No
Yes
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August 2004, VA.00
MBI5171
Block Diagram
8-Bit Constant Current LED Driver with
LED Error Detection and Run-Time Current Adjustment
OUT0
OUT
1
OUT6
OUT7
R-EXT
VDD
I
OUT
Regulator
OE /SW/ ED
Control Logic
LE/MOD/CA
GND
8-Bit Output Driver
8
8
8-Bit Output Latch
8
SDO
8
8-Bit Configuration Latch
CLK
8
8-Bit Shift Register
SDI
Equivalent Circuits of Inputs and Outputs
OE/SW/ ED Terminal
VDD
LE/MOD/CA Terminal
VDD
OE/SW/ ED
LE/MOD/CA
CLK, SDI Terminal
VDD
SDO Terminal
VDD
CLK, SDI
SDO
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August 2004, VA.00
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