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Datasheet
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Features
l l Compatible with MBI5168 in package and electrical characteristics Exploit Share-I-OTM technique to provide two operation modes: Normal Mode with the same functionality as MB5168, Current Adjust Mode to program output current gain l l l l 8 constant-current output channels Output current adjustable through an external resistor Constant output current range: 5 -120 mA Excellent output current accuracy, between channels < 3% (max.), and between ICs < 6% (max.). l l Constant output current invariant to load voltage change Fast response of output current, OE (min.): 200 ns @Iout < 60mA OE (min.): 400 ns @Iout = 60~100mA l l l l 25MHz clock frequency Schmitt trigger input 3.3V~ 5V supply voltage 256-step run-time programmable output current gain suitable for white balance application
MBI5170CDW MBI5168CDW
SOP16-150-1.27 Weight0.13g P-DIP16-300-2.54 Weight1.02g
M BMBI5168CN N I5 0 0 1 MBI5170CN C
MBI5001CN
MBI5001CD
MBI5170CD MBI5168CD
MBI5001CD
SOP16-300-1.27 Weight0.37g
MBI5168CP
MBI5170CP
Current Accuracy Between Channels < 3% Between ICs < 6%
Conditions IOUT = 10 ~ 100 mA, VDS = 0.8V, VDD = 5.0V
SSOP16-150-0.64 Weight0.07g
(c)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 -1August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Product Description
MBI5170 succeeds MBI5168 and also exploits PrecisionDriveTM technology to enhance its output characteristics. Furthermore, MBI5170 uses the idea of Share-I-OTM technique to make MBI5170 backward compatible with MBI5168 in both package and electrical characteristics and extend its functionality for run-time LED current gain control in LED display systems. MBI5170 contains an 8-bit Shift Register and an 8-bit Output Latch, which convert serial input data into parallel output format. At MBI5170 output stages, eight regulated current ports are designed to provide uniform and constant current sinks with small skew between ports for driving LED's with 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. MBI5170 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. By means of the Share-I-OTM technique, MBI5170 adds new functionality on the pins LE and OE of MBI5168 to provide an additional function, Current Gain Control, without any extra pins. Thus, MBI5170 could be a drop-in replacement of MBI5168. The printed circuit board originally designed for MBI5168 may be also applied to MBI5170. In MBI5170 there are two operation modes and three phases: Normal Mode phase, Mode Switching transition phase, and Current Adjust Mode phase. The signal on the multi-function pin OE /SW would be monitored. Once a one-clock-wide short pulse appears on the pin OE /SW, MBI5170 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 MBI5170 is going to switch. In the Normal Mode phase, MBI5170 has similar functionality to MBI5168. The serial data could be transferred into MBI5170 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 would enable the output drivers to sink current. On the other hand, the Current Adjust Mode phase allows users to adjust the output current level by setting a run-time programmable Configuration Code. The code is sent into MBI5170 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 current gain ranging from (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.
Pin Assignment
GND SDI CLK LE/MOD/CA OUT 0 OUT1 OUT2 OUT3 1 2 3 4 5 6 7 8 16 15 14 13 12 11 10 9 VDD R-EXT SDO OE/SW OUT7 OUT6 OUT5 OUT4
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
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 on 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 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 MBI5170 is going to switch. When LE/MOD/CA is high, the next mode is the Current Adjust Mode; when low, the next mode is the Normal Mode. Configuration data strobe input terminal: in the Current Adjust 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) Output enable terminal: no matter in what phase MBI5170 operates, the signal OE /SW 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: a one-clock-wide short signal pulse of OE /SW could put MBI5170 into the Mode Switching phase. (See Operation Principle) Serial-data output to the following SDI of next driver IC Input terminal used to connect an external resister for setting up all output current Supply voltage terminal
4
LE/MOD/CA
5-12
OUT0 ~ OUT7 Constant current output terminals
13
OE /SW
14 15 16
SDO R-EXT VDD
In MBI5170, the relationship between the functions of pin 4 and 13 and the operation phases is listed below: Pin No. Pin Name Function LE: latching serial data into the Output Latch 4 LE/MOD/CA MOD: mode selection CA: latching serial data into the Configuration Latch 13 OE /SW OE : enabling the current output drivers SW: entering the Mode Switching phase Normal Mode Yes No No Yes Yes Mode Switching No Yes No Yes Yes Current Adjust Mode No No Yes Yes Yes
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Block Diagram
OUT0 OUT1 OUT6 OUT7
R-EXT
VDD
IOUT Regulator
OE /SW Control Logic LE/MOD/CA
GND
8-Bit Output Driver 8 8 8-Bit Output Latch 8 SDO
8-Bit Configuration Latch CLK 8 8-Bit Shift Register
SDI
Equivalent Circuits of Inputs and Outputs
OE /SW Terminal
VDD
LE/MOD/CA Terminal
VDD
OE /SW
LE/MOD/CA
CLK, SDI Terminal
VDD
SDO Terminal
VDD
CLK, SDI
SDO
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Timing Diagram Normal Mode
N= 0 1 2 3 4 5 6 7
CLK SDI
LE/MOD/CA OE /SW
OFF ON OFF ON
OUT0 OUT1 OUT2
OFF ON OFF
OUT3
ON
OFF
OUT6
ON OFF
OUT7
ON
SDO
: don't care
Truth Table (In Normal Mode)
CLK LE/MOD/CA H L H X X OE /SW L L L L H SDI Dn Dn+1 Dn+2 Dn+3 Dn+3 OUT0 ... OUT5 ... OUT 7 Dn ..... Dn - 5 .... Dn - 7 No Change Dn + 2 .... Dn - 3 .... Dn - 5 Dn + 2 .... Dn - 3 .... Dn - 5 Off SDO Dn-7 Dn-6 Dn-5 Dn-5 Dn-5
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
1 2 3 4 5
Switching to Current Adjust Mode
CLK
OE /SW
1 0
0 0
1 0
1 1
1 0
LE/MOD/CA
The above shows an example of the signal sequence that can set the next operation mode of MBI5170 to be the Current Adjust Mode. The LE/MOD/CA active pulse here would not latch any serial data.
Writing Configuration Code (In Current Adjust Mode)
N=0 1 2 3 4 5 6 7
CLK LE/MOD/CA SDI
Bit7
8-Bit Configuration Code
Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
In the Current Adjust Mode, by sending the positive pulse of LE/MOD/CA, the content of the Shift Register with a Configuration Code will be written to the 8-bit Configuration Latch.
Switching to Normal Mode
1 2 3 4 5
CLK
OE /SW
1 0
0 0
1 0
1 0
1 0
Voltage Low
LE/MOD/CA
The above signal sequence example can make MBI5170 resume to the Normal Mode. Note: If users want to know the whole process, that is how to enter the Current Adjust Mode, write the Configuration Code, and resume to the Normal Mode, please refer to the section Operation Principle.
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Maximum Ratings
Characteristics Supply Voltage Input Voltage Output Current Output Voltage Clock Frequency GND Terminal Current CN - type Power Dissipation (On PCB, Ta=25C) CD - type CDW - type CP - type CN - type Thermal Resistance (On PCB, Ta=25C) CD - type CDW - type CP - type Operating Temperature Storage Temperature Topr Tstg Rth(j-a) PD Symbol VDD VIN IOUT VDS FCLK IGND Rating 0 ~ 7.0 -0.4 ~ VDD + 0.4 +120 -0.5 ~ +20 25 1000 2.03 1.46 2.03 1.32 61.65 85.82 61.63 94.91 -40 ~ +85 -55 ~ +150 C C C/W W Unit V V mA V MHz mA
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Recommended Operating Conditions
Characteristics Supply Voltage Output Voltage Symbol VDD VDS IOUT Output Current IOUT IOH IOL VIH Input Voltage VIL CLK Pulse Width Setup Time for SDI Hold Time for SDI LE/MOD/CA Pulse Width Setup Time for LE/MOD/CA Hold Time for LE/MOD/CA Setup Time for LE/MOD/CA Hold Time for LE/MOD/CA tw(CLK) tsu(D) th(D) tw(L) tsu(L) th(L) tsu(MOD) th(MOD) tw(SW) OE /SW Pulse Width tw(OE) tw(OE) Setup Time for OE /SW Hold Time for OE /SW Clock Frequency tsu(SW) th(SW) FCLK To trigger Mode Switching Iout < 60mA Iout = 60~100mA To trigger Mode Switching Cascade Operation (VDD= 5.0V) For data strobe in both Normal Mode and Current Adjust Mode In Mode Switching Condition OUT0 ~ OUT7 OUT0 ~ OUT7 , CM*=1, VDD =5V OUT0 ~ OUT7 , CM*=0, VDD =5V SDO SDO CLK, OE /SW, LE/MOD/CA, and SDI CLK, OE /SW, LE/MOD/CA, and SDI Min. 4.5 10 5 0.7VDD -0.3 20 5 10 20 5 10 5 10 20 200 400 5 10 Typ. 5.0 Max. 5.5 17.0 120 40 -1.0 1.0 VDD+0.3 0.3VDD 25.0 Unit V V mA mA mA mA V V ns ns ns ns ns ns ns ns ns ns ns ns ns MHz
* CM is one bit in configuration code and called as "Current Multiplier." It would affect the ratio of IOUT to Irext. The detail information could be found in the section Operation Principle.
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Electrical Characteristics (VDD= 5.0V)
Characteristics Supply Voltage Output Voltage Symbol VDD VDS IOUT Output Current IOUT IOH IOL Input Voltage "H" level "L" level VIH VIL OUT0 ~ OUT7 OUT0 ~ OUT7 , CM= 1 OUT0 ~ OUT7 , CM= 0 SDO SDO Ta = -40~85C Ta = -40~85C VDS=17.0V and channel off VOL VOH Output Current 1 Current Skew (between channels) Output Current 2 Current Skew (between channels) Output Current 3 Current Skew (between channels) Output Current vs. Output Voltage Regulation Output Current vs. Supply Voltage Regulation Pull-up Resistor Pull-down Resistor IOUT1 dIOUT1 IOUT2 dIOUT2 IOUT3 dIOUT3 %/dVDS %/dVDD RIN(up) IOL=+1.0mA IOH=-1.0mA VDS = 0.5V; Rext = 744; VG** = 0.992; CM = 1 IOUT = 25mA Rext=744 VDS 0.5V VDS = 0.6V; Rext = 372; VG** = 0.992; CM = 1 IOUT = 50mA Rext=372 VDS 0.6V VDS = 0.8V; Rext = 186; VG** = 0.992; CM = 1 IOUT = 100mA Rext=186 VDS 0.8V VDS within 1.0V and 3.0V VDD within 4.5V and 5.5V OE /SW Rext=Open, OUT0 ~ OUT7 =Off; CM = 1, VG= 0.992 Rext=744 , OUT0 ~ OUT7 =Off; CM = 1, VG= 0.992 Rext=372 , OUT0 ~ OUT7 =Off; CM = 1, VG= 0.992 Rext=186 , OUT0 ~ OUT7 =Off; CM = 1, VG= 0.992 Rext=744 , OUT0 ~ OUT7 =On; CM = 1, VG= 0.992 Rext=372 , OUT0 ~ OUT7 =On; CM = 1, VG= 0.992 Rext=186 , OUT0 ~ OUT7 =On; CM = 1, VG= 0.992 Condition Min. 4.5 10 5 0.7VDD GND 4.6 250 250 Typ. 5.0 25.0 1 50.0 1 100 1 0.1 1 500 500 3.3 5.9 8.5 13.7 5.9 8.5 13.7 Max. 5.5 17.0 120 40 -1.0 1.0 VDD 0.3VDD 0.5 0.4 3 3 3 800 800 mA Unit V V mA mA mA mA V V A V V mA % mA % mA % %/V %/V K K
Output Leakage Current Output Voltage
SDO
RIN(down) LE/MOD/CA IDD(off) 0 IDD(off) 1
"OFF" IDD(off) 2 Supply Current IDD(off) 3 IDD(on) 1 "ON" IDD(on) 2 IDD(on) 3
** In the above table, VG is the programmable gain of the voltage at the terminal R-EXT. The detail description could be found in the section Operation Principle.
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Electrical Characteristics (VDD= 3.3V)
Characteristics Supply Voltage Output Voltage Symbol VDD VDS IOUT Output Current IOUT IOH IOL Input Voltage "H" level "L" level VIH VIL OUT0 ~ OUT7 OUT0 ~ OUT7 , CM=1, OUT0 ~ OUT7 , CM=0, SDO SDO Ta = -40~85C Ta = -40~85C VDS=17.0V and channel off VOL VOH Output Current 1 Current Skew (between channels) Output Current 2 Current Skew (between channels) Output Current vs. Output Voltage Regulation Output Current vs. Supply Voltage Regulation Pull-up Resistor Pull-down Resistor IOUT1 dIOUT1 IOUT2 dIOUT2 %/dVDS %/dVDD RIN(up) IOL=+1.0mA IOH=-1.0mA VDS = 0.5V; Rext = 744; VG = 0.992; CM = 1 IOUT = 25mA Rext=744 VDS 0.5V VDS = 0.6V; Rext = 372; VG = 0.992; CM = 1 IOUT = 50mA Rext=372 VDS 0.6V VDS within 1.0V and 3.0V VDD within 3.2V and 3.6V OE /SW Rext=Open, OUT0 ~ OUT7 =Off; CM = 1, VG= 0.992 Rext=744 , OUT0 ~ OUT7 =Off; CM = 1, VG= 0.992 Rext=372 , OUT0 ~ OUT7 =Off; CM = 1, VG= 0.992 Rext=744 , OUT0 ~ OUT7 =On; CM = 1, VG= 0.992 Rext=372 , OUT0 ~ OUT7 =On; CM = 1, VG= 0.992 Condition Min. 3.0 10 5 0.7VDD GND 2.9 250 250 Typ. 3.3 25.0 1 50.0 1 0.1 1 500 500 0.87 3.7 6.37 3.4 6.1 Max. 3.6 17.0 120 40 -1.0 1.0 VDD 0.3VDD 0.5 0.4 3 3 800 800 mA Unit V V mA mA mA mA V V A V V mA % mA % %/V %/V K K
Output Leakage Current Output Voltage
SDO
RIN(down) LE/MOD/CA IDD(off) 0
"OFF" Supply Current "ON"
IDD(off) 1 IDD(off) 2 IDD(on) 1 IDD(on) 2
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Switching Characteristics (VDD= 5.0V)
Characteristics CLK - OUTn Propagation Delay LE/MOD/CA - OUTn Time ("L" to "H") OE /SW - OUTn CLK - SDO CLK - OUTn Propagation Delay LE/MOD/CA - OUTn Time ("H" to "L") OE /SW - OUTn CLK - SDO CLK Pulse Width LE/MOD/CA OE /SW (@Iout< 60mA) Hold Time for LE/MOD/CA Setup Time for LE/MOD/CA Maximum CLK Rise Time Maximum CLK Fall Time Output Rise Time of Vout (turn off) Output Fall Time of Vout (turn on) Clock Frequency Symbol tpLH1 tpLH2 tpLH3 tpLH tpHL1 tpHL2 tpHL3 tpHL tw(CLK) tw(L) tw(OE) th(L) tsu(L) tr*** tf*** tor tof FCLK Cascade Operation Test Circuit for Switching Characteristics VDD=5.0 V VDS=0.8 V VIH=VDD VIL=GND Rext=372 VL=4.0 V RL=64 CL=10 pF VG = 0.992 CM = 1 Condition Min. 20 20 20 20 200 10 5 Typ. 100 100 100 25 100 100 100 25 120 200 Max. 150 150 150 30 150 150 150 30 500 500 150 250 25.0 Unit ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns MHz
*** If MBI5170 are connected in cascade and tr or tf is large, it may be critical to achieve the timing required for data transfer between two cascaded LED drivers MBI5170.
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Switching Characteristics (VDD= 3.3V)
Characteristics CLK - OUTn Propagation Delay LE/MOD/CA - OUTn Time ("L" to "H") OE /SW - OUTn CLK - SDO CLK - OUTn Propagation Delay LE/MOD/CA - OUTn Time ("H" to "L") OE /SW - OUTn CLK - SDO CLK Pulse Width LE/MOD/CA OE /SW (@IOUT< 60mA) Hold Time for LE/MOD/CA Setup Time for LE/MOD/CA Maximum CLK Rise Time Maximum CLK Fall Time Output Rise Time of Vout (turn off) Output Fall Time of Vout (turn on) Clock Frequency Symbol tpLH1 tpLH2 tpLH3 tpLH tpHL1 tpHL2 tpHL3 tpHL tw(CLK) tw(L) tw(OE) th(L) tsu(L) tr tf tor tof FCLK Cascade Operation Test Circuit for Switching Characteristics VDD=3.3 V VDS=0.8 V VIH=VDD VIL=GND Rext=372 VL=4.0 V RL=64 CL=10 pF VG = 0.992 CM = 1 Condition Min. 45 45 20 20 200 10 5 Typ. 100 100 100 55 130 130 130 55 120 200 Max. 150 150 150 65 200 200 200 65 500 500 150 400 12.0 Unit ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns ns MHz
Test Circuit for Electrical Characteristics
IDD
Test Circuit for Switching Characteristics
IDD
VDD
IOUT
OUT0
IOUT
VIH, VIL
OE /SW
VDD OUT0
OE /SW
IIH,IIL
CLK LE/MOD/CA SDI R - EXT GND
. . . .
Function Generator
CLK LE/MOD/CA SDI
. . .
OUT7
OUT7
RL
SDO Logic Input Waveform R - EXT GND SDO
CL
VL
VIH, VIL
Iref
VIH = VDD VIL = GND tr = tf = 10 ns
Iref
CL
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Timing Waveform Normal Mode and Current Adjust Mode
tW(CLK)
CLK
50%
50%
50%
tsu(D)
th(D)
50%
SDI
50%
SDO
tpLH, tpHL
50%
tW(L)
50% 50%
LE/MOD/CA
th(L) OE /SW
tsu(L)
LOW = OUTPUTS ENABLED HIGH = OUTPUT OFF
OUTn tpLH1, tpHL1 tpLH2, tpHL2
50%
LOW = OUTPUT ON
tW(OE) OE /SW
50% 50%
tpHL3
90% 50% 10%
tpLH3
90% 50% 10%
OUTn
tof
tor
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Switching to Current Adjust Mode
tW(CLK)
CLK
50%
50%
50%
tsu(MOD) th(MOD)
LE/MOD/CA
50%
50%
2 CLK
tsu(SW)
50%
th(SW)
OE /SW
50%
tW(SW)
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Operation Principle Constant Current
In LED display applications, MBI5170 provides nearly no current variations from channel to channel and from IC to IC. This can be achieved by: 1) While IOUT 100mA, the maximum current skew between channels is less than 3%, and that between IC's is less than 6%. 2) In addition, the characteristics curve of output stage in the saturation region is flat and users can refer to the output characteristics figure as shown below. Thus, the output current can be kept constant regardless of the variations of LED forward voltage (Vf).
Iout v.s. VDS curve for various Rext (VDD= 5.0V) 140 120 100 Iout (mA) 80 60 40 20 0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 VDS (V)
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Adjusting Output Current
MBI5170 scales up the reference current Iref set by the external resistor Rext to sink a current Iout at each output port. Users can follow the below formulas to calculate the output current Iout in the saturation region: VR-EXT = 1.25Volt x VG Irext = VR-EXT / Rext Iout = Irext x 15 x 3^(CM-1) where Rext is the resistance of the external resistor connected to the R-EXT terminal, and VR-EXT is the voltage of the R-EXT terminal and controlled by the programmable voltage gain VG, which is defined by the Configuration Code. The Current Multiplier CM would determine that the ratio Iout/Irext is 15 or 5. After power-on, the default Based on the if another end of the external resistor Rext is connected to ground.
value of VG is 127/128 = 0.992 and the default value of CM is 1, so that the ratio Iout/Irext is 15. default VG and CM, VR-EXT = 1.25Volt x 127/128= 1.24Volt Iout = (1.24Volt / Rext ) x 15
Hence, the default magnitude of current is around 50mA at 372 and 25mA at 744. The default relationship after power-on between Iout and Rext is shown in the following figure.
Default Relationship Curve Between Iout and Rext After Power-On
140 120 100
80 60 40 20 0 0 500 1000 1500 2000
VDS= 1.0V VDD= 5.0V VG = 127/128 CM = 1
Iout (mA)
2500
3000
3500
4000
Rext ()
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Operation Phases
MBI5170 exploits the Share-I-OTM technique to extend the functionality of pins in MBI5168 in order to provide run-time programmable LED driving current in the Current Adjust Mode phase as well as the original function of MBI5168 in the Normal Mode phase. In order to switch between the two modes, MBI5170 monitors the signal OE /SW. Once a one-clock-wide pulse of OE /SW appears, MBI5170 would enter the two-clock-period transition phase---the Mode Switching phase. After power-on, the default operation mode is the Normal Mode.
Operation Mode Switching
Switching to the Current Adjust Mode
1 2 3 4 5
Switching to the Normal Mode
1 2 3 4 5
CLK OE /SW LE/MOD/CA Phase
CLK
1 x
0 x
1 x
x 1
Voltage High Mode Switching
x x
Current Adjust Mode
OE /SW LE/MOD/CA Phase
1 x
0 x
1 x
x 0
Voltage Low Mode Switching
x x
Normal Mode
Current Adjust Mode or Normal Mode
Current Adjust Mode or Normal Mode
As shown in the above figures, once a one-clock-wide short pulse "101" of OE /SW appears, MBI5170 would enter the Mode Switching phase. At the 4 rising edge of CLK, if LE/MOD/CA is sampled as "Voltage High", MBI5170 would switch to the Current Adjust Mode; otherwise, it would switch to the Normal Mode. Worthwhile noticing, the signal LE/MOD/CA between the 3 and the 5 rising edges of CLK can not latch any data. Its level is just used for determining which mode to switch. However, the short pulse of OE /SW can still enable the output ports. During the mode switching, the serial data can still be transferred through the pin SDI and shifted out from the pin SDO. Note: 1. The signal sequence for the mode switching could be frequently used for making sure under which mode MBI5170 is working. 2. The aforementioned "1" and "0" are sampled at the rising edge of CLK. The "X" means its level would not affect the result of mode switching mechanism.
rd th th
Normal Mode Phase
MBI5170 in the Normal Mode phase has similar functionality to MBI5168. The only difference is short pulse OE /SW signal monitoring. The short pulse would trigger MBI5170 to switch its operation mode. However, as long as the signal LE/MOD/CA is not Voltage High in the Mode Switching phase, MBI5170 would still remain in the Normal Mode as if no mode switching occurs.
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
N=0 1 2 3 4 5 6 7
Current Adjust Mode Phase and Writing Configuration Code
CLK LE/MOD/CA SDI
Bit7
8-Bit Configuration Code
Bit6 Bit5 Bit4 Bit3 Bit2 Bit1 Bit0
In the Current Adjust Mode phase, the serial data could be transferred into MBI5170 via the pin SDI, shifted in the Shift Register, and go out via the pin SDO. The active low signal OE /SW can enable the output drivers to sink current. These are the same as those in the Normal Mode. The difference is that the active high signal LE/MOD/CA latches the serial data in the Shift Register to the Configuration Latch, instead of the Output Latch. The latched serial data is regarded as the Configuration Code. The code would be memorized until power off or the Configuration Latch is re-written. As shown above, the timing for writing the Configuration Code is the same as that in the Normal Mode for latching output channel data.
8-Bit Configuration Code and Current Gain CG
Bit Definition of 8-Bit Configuration Code Bit 0
Meaning Default Value
Bit 1 HC 1
Bit 2 CC0 1
Bit 3 CC1 1
Bit 4 CC2 1
Bit 5 CC3 1
Bit 6 CC4 1
Bit 7 CC5 1
CM 1
Bit definition of the Configuration Code in the Configuration Latch is shown above. Bit 7 is first sent into MBI5170 via the pin SDI. Bit 1 ~ 7, {HC, CC[0:5]}, would determine the voltage gain (VG), that affects the voltage at R-EXT terminal and indirectly the reference current Irext flowing through the external resistor at terminal R-EXT. Bit 0 is the Current Multiplier (CM) bit, that determines the ratio Iout/Irext. Each combination of VG and CM would give a Current Gain (CG). l VG: the relationship between {HC,CC[0:5]} and the Voltage Gain G can be formulated as below: VG = (1 + HC) x (1 + D/64) / 4 D = CC0 x 2 + CC1 x 2 + CC2 x 2 + CC3 x 2 + CC4 x 2 + CC5 x 2
5 4 3 2 1 0
where HC is 1 or 0, and D is the binary value of CC[0:5]. So, the VG could be regarded as a floating-point number with one bit exponent HC and 6-bit mantissa CC[0:5]. {HC,CC[0:5]} divides the programmable voltage gain VG into 128 steps and two sub-bands: Low voltage sub-band (HC=0): VG = 1/4 ~ 127/256, linearly divided into 64 steps; High voltage sub-band (HC=1): VG = 1/2 ~ 127/128, linearly divided into 64 steps, too. l CM: as well as determining the ratio Iout/Irext, the CM bit would limit the output current range. High Current Multiplier (CM=1): Iout/Irext = 15 and suitable for output current range Iout = 10 ~ 120mA. Low Current Multiplier (CM=0): Iout/Irext = 5 and suitable for output current range Iout = 5 ~ 40mA.
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August 2004, VA.00
MBI5170
l
8-Bit Constant Current LED Sink Driver with Gain Control
CG: the total Current Gain is defined as the following. VR-EXT = 1.25Volt * VG Irext = VR-EXT / Rext if another end of the external resistor Rext is connected to ground.
Iout = Irext * 15 * 3^(CM-1) = 1.25Volt / Rext * VG * 15 * 3^(CM-1) = (1.25Volt / Rext * 15) * CG We define CG = VG * 3^(CM-1). Hence CG = (1/12) ~ (127/128) and it is divided into 256 steps, totally. If
CG = 127/128 = 0.992, the Iout-Rext relationship is similar to that in MBI5168. For example, a) When the Configuration Code {CM, HC, CC[0:5]} = {1,1,111111}, VG = 127/128 = 0.992; and CG = VG * 3^0 = VG = 0.992 b) When the Configuration Code is {1,1,000000}, VG = (1+0)*(1+0/64)/4 = 1/2 = 0.5; and CG = 0.5 c) When the Configuration Code is {0,0,000000}, VG = (1+0)*(1+ 0/64)/4 = 1/4; and CG = (1/4)*3^-1 = 1/12 After power on, the default value of the Configuration Code {CM, HC, CC[0:5]} is {1,1,111111}. Thus, VG = CG = 0.992. The relationship between the Configuration Code and the Current Gain CG is shown in the following.
Current Gain CG v.s. Configuration Code in Binary Format
1.00 0.95 0.90 0.85 0.80 0.75 0.70 0.65 0.60 0.55 0.50 0.45 0.40 0.35 0.30 0.25 0.20 0.15 0.10 0.05 0.00 {0,0,000000}
CM =0 (Low Current Multiplier)
HC = 0 (Low Voltage SubBand) HC = 1 (High Voltage SubBand) HC = 0 (Low Voltage SubBand) HC = 1 (High Voltage SubBand)
Current Gain CG
CM=1 (High Current Multiplier)
{0,0,010000}
{0,0,100000}
{0,0,110000}
{0,1,000000}
{0,1,010000}
{0,1,100000}
{0,1,110000}
{1,0,000000}
{1,0,010000}
{1,0,100000}
{1,0,110000}
{1,1,000000}
{1,1,010000}
{1,1,100000}
Configuration Code {CM,HC,CC[0:5]} in Binary Format
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August 2004, VA.00
{1,1,110000}
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control 8-Bit Constant Current LED Sink Driver with Gain Control
Timing Chart for Current Adjust Mode (An Example)
N of MBI5170 are connected in cascade, i.e., SDO, k --> SDI, k+1. And, all MBI5170 are connected to the same signal bus CLK, LE/MOD/CA and OE /SW. SDO, 0 SDI, 0 CLK LE/MOD/CA OE /SW 1 CLK SDI, 0 2 3 4 5 N x 8 CLK Pulses (Note 1) 1 2 3 4 5 MBI5170, 0 SDI, 1 SDO, 1 MBI5170, 2 SDO, 2
MBI5170, N-2 MBI5170, N-1
SDO, N-1
MBI5170, 1
CC0 CC5 CC2 CC1 HC CC4 -CC3 -
-CM
CC5 CC4 CC3 CC2 CC1 CC HC CC0
-CM -
CC5 -CC4 -CC3 CC2 -CC1 CC0 -HC -CM -
CC5 CC4 CC3 CC2 CC1 CC0 HC
--CM
Configuration Codes (Note 1) (Note2) For MBI5170, N- 1 LE/MOD/CA For MBI5170, N-2 For MBI5170, 1 For MBI5170, 0
OE /SW
LE/MOD/CA Pulse (Note 3)
Writing the Configuration Codes, Code k, k = 0... (N x 8 -1) A Entering the Current Adjust Mode B N x 8 CLK pulses are required to shift the 8-bit Configuration Codes needed by N of MBI5170. Note 2: Voltage Gain VG = (1+ HC) x (1 + D/64)/4 D = CC0 x 25+ CC1 x 24 + CC2 x 23 + CC3 x 22 + CC4 x 21 + CC5 x 20 . Current Gain CG = VG * 3^(CM-1) Note 3: The LE/MOD/CA pulse writes the Configuration Codes to each MBI5170. C Resuming to the Normal Mode
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Application Information Package Power Dissipation (PD)
The maximum allowable package power dissipation is determined as PD(max) = (Tj - Ta) / Rth(j-a). When 8 output channels are turned on simultaneously, the actual package power dissipation is PD(act) = (IDD x VDD) + (IOUT x Duty x VDS x 8) Therefore, to keep PD(act) PD(max), the allowable maximum output current as a function of duty cycle is IOUT = { [ (Tj - Ta) / Rth(j-a) ] - (IDD x VDD) } / VDS / Duty / 8 where Tj = 150C.
Iout vs. Duty Cycle at Rth = 61.65 (C/W) 120 110 100 90 80 Iout (mA) Iout (mA) 70 60 50 40 30 20 10 5% 10% 15% 20% 25% 30% 35% 40% 45% 50% 55% 60% 65% 70% 75% 80% 85% 90% 95% 100% 0 120 110 100 90 80 70 60 50 40 30 20 10 5% 10% 15% 20%
Iout vs. Duty Cycle at Rth = 85.82 ( C/W)
25%
30%
35%
40%
45%
50%
55%
60%
65%
70%
75%
80%
85%
90%
95% 95%
Duty Cycle
Duty Cycle
CN Device Type
CD Device Type
Iout vs. Duty Cycle at Rth = 61.63 ( C/W) 120 110 100 90 80 Iout (mA) Iout (mA) 70 60 50 40 30 20 10 5% 10% 15% 20% 25% 30% 35% 40% 45% 50% 55% 60% 65% 70% 75% 80% 85% 90% 95% 100% 0 120 110 100 90 80 70 60 50 40 30 20 10 5% 10% 15% 20%
Iout vs. Duty Cycle at Rth = 94.91 ( C/W)
25%
30%
35%
40%
45%
50%
55%
60%
65%
70%
75%
80%
85%
90%
Duty Cycle
Duty Cycle
CDW Device Type
CP Device Type
ConditionVDS = 1.0V, VDD = 5.0V, 8 output channels active, Ta is listed in the legend below. Device Type CN CD CDW CP Rth(j-a)(C/W) 61.65 85.82 61.63 94.91
25 55 85
Note
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August 2004, VA.00
100%
0
100%
0
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Load Supply Voltage (VLED)
Considering the package power dissipating limits, users had better apply MBI5170 to operate within VDS = 0.4V~ 1.0V. If VLED is higher, for instance, than 5V, VDS may be so high that PD(act) > PD(max) ,where VDS = VLED - Vf. In this case, it is recommended to use as low supply voltage as possible or to arrange a voltage reducer, VDROP. The voltage reducer lets VDS = (VLED - Vf) - VDROP. Resistors or Zener diodes can be used as the reducers in the applications as shown in the following figures.
VLED
VLED VDROP
VDROP
Vf VDS
Vf
VDS
MBI5170
MBI5170
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
Outline Drawings
MBI5170CN Outline Drawing
MBI5170CD Outline Drawing
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August 2004, VA.00
MBI5170
8-Bit Constant Current LED Sink Driver with Gain Control
MBI5170CDW Outline Drawing
MBI5170CP Outline Drawing
MBI5170 Package Information
Device Type CN CD CDW CP Package Type P-DIP16-300-2.54 SOP16-150-1.27 SOP16-300-1.27 SSOP16-150-0.64 Weight (g) 1.02 0.13 0.37 0.07
Note: The unit for the outline drawing is mm.
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August 2004, VA.00

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