SEMTECH SC5014

SC5014
High Efficiency 4-Channel HB LED Driver with
I2C Interface and Phase-Shifted PWM Dimming
POWER MANAGEMENT
Features







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Description
Input Voltage — 4.5V to 27V
Output Voltage — Up to 50V
Step-up (Boost) Controller
 Ultra-Fast Transient Response (<100μs)
 Programmable Switching Frequency
Linear Current Sinks
 4 Strings, up to 120mA/String
 Current Matching ±1%
 Current Accuracy ±2%
PWM Dimming
 String-by-String Phase Shifting
 Input Dimming Frequency 100Hz-30kHz
 User Selectable 9 or 10-Bits Dimming Resolution
5-Bits Analog Dimming
I2C Interface
 Fault Status — Open/Short LED, UVLO, OTP
 Device Control: PLL Setting
Protection Features

Open/Shorted LED(s) and adjustable OVP

Over-Temperature and UVLO Shutdown Protection
4mm X 4mm 20-pin QFN Package
Applications
UltrabooksTM, All-in-One PCs, Monitors, AutomotiveDisplay Backlighting
 Backlighting for Mid-Size Displays

The SC5014 is a 4-channel, highly integrated, high-efficiency step-up (boost) HB LED driver designed to reduce
the thickness of mid-size LCD displays. It features a wide
input voltage range (4.5V to 27V), phase-shifted PWM
dimming, analog dimming, a flexible output configuration, an I2C interface, and numerous protection features.
The SC5014 exhibits 2% to 4% higher efficiency when
using the same size inductors as existing LED drivers. But,
unlike existing devices, it can also operate with inductors
that are up to 10x smaller without sacrificing efficiency.
This part can also use very low-profile inductors (as small
as 2.2µH, 1mm height), which allows LED drivers to be
built directly into the LCD panel to enable ultra-thin
displays.
The boost controller, with programmable switching frequency from 200kHz to 2.2MHz, maximizes efficiency by
dynamically minimizing the output voltage while maintaining LED string current accuracy. It provides excellent
line and load response with no external compensation
components. An external resistor adjusts the current from
20-120mA per string. It also features PWM dimming resolution of 9 or 10-bits (user selectable) over a dimming frequency from 100Hz to 20kHz, synchronized to the boost
oscillator. String-by-string phase shifting reduces the
demand on the input/output capacitance, decreases EMI,
and improves dimming linearity.
Typical Application Circuit
VIN=4.5to27V
L1
NDRV
R1
R2
VCC=4.5to5.5V
R3
EN
PWMI
C3
R6
R11
C4
C5
R8
OVP
R9
SC5014
IO1
Upto
120mA/String
IO2
REF
IO3
SCP
IO4
R5
R10
Revision 2.0
FLT
SDA
SCL
PWMI
Q1
R4
UVLO
EN
ForI2C
VOUTupto50V
CS
VCC
FLT
D1
R7
FSET
ISET
CPLL
E-PAD
PGND
SC5014
NDRV
PGND
CS
20
19
18
17
16
UVLO 1
15
OVP
SCP 2
14
IO1
REF 3
13
IO2
FSET 4
12
IO3
CPLL 5
11
IO4
Package
SC5014MLTRT(1)(2)
MLPQ-20 4×4
SC5014EVB
Evaluation Board
Notes:
(1) Available in tape and reel only. A reel contains 3,000 devices.
(2) Lead-free packaging only. Device is WEEE and RoHS compliant,
and halogen free.
PWMI
FLT
SDA
10
ISET
9
8
7
6
SCL
AGND
Device
VCC
Ordering Information
EN
Pin Configuration
Marking Information
5014
yyww
xxxxx
xxxxx
nnnn = Part Number
yyww = Date code
xxxxx = Semtech Lot No.
xxxxx = Semtech Lot No.
SC5014
Absolute Maximum Ratings (refer to PGND)
Recommended Operating Conditions
VCC Pin (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +6.0
Ambient Temperature Range (°C). . . . . . . . . -40 < TA < +85
VIN, IO1 to IO4 (V). . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +30
VIN (V). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 to 27
DRVN, OVP, CS, EN, UVLO, SCP, REF, FLT (V) . . -0.3 to +6.0
IO1 to IO4 Current per String (mA) . . . . . . . . . . . 125 (max)
FSET, CPLL, SCL, SDA, ISET, PWMI (V) . . . . . . . -0.3 to +6.0
Thermal Information
PGND to AGND (V). . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to +0.3
ESD Protection Level(1) (kV) ������������������������������������������������������� 2
Thermal Resistance, Junction to Ambient(2) (°C/W) . . . . 32
Maximum Junction Temperature (°C). . . . . . . . . . . . . . . +150
Storage Temperature Range (°C) . . . . . . . . . . . . -65 to +150
Peak IR Reflow Temperature (10s to 30s) (°C) . . . . . . . +260
Exceeding the above specifications may result in permanent damage to the device or device malfunction. Operation outside of the parameters
specified in the Electrical Characteristics section is not recommended.
NOTES:
(1) Tested according to JEDEC standard JESD22-A114-B.
(2) Calculated from package in still air, mounted to 3 x 4.5in, 4-layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards.
Electrical Characteristics
Unless noted otherwise, TA = 25°C for typical, -40°C < TA = TJ < 85°C for min and max. VCC = 5V, RISET = 25.5KΩ, RFSET = 100KΩ.
Parameter
Symbol
Conditions
Min
Typ
Max
Units
5.5
V
4.4
V
Input Supply
VCC Supply Voltage
VCC
4.5
VCC Under-Voltage Lockout Threshold
VCC-UVLO(TH)
VCC Voltage Rising
4.2
VCC Under-Voltage Lockout Hysteresis
VCC-UVLO(HYS)
VCC Voltage Falling
180
mV
VCC Quiescent Supply Current
ICC(Q)
EN = 5V, Switching, No Load
2
mA
VCC Supply Current in Shutdown
ICC(SD)
EN = 0V
VUVLO Under-Voltage Lockout Threshold
VUVLO(TH)
UVLO Pin Voltage Rising
1.18
IUVLO Under-Voltage Lockout Hysteresis
IUVLO(HYS)
UVLO Pin Voltage Falling
VREF Bandgap Voltage
VREF
1
µA
1.23
1.28
V
7
10
13
µA
1.20
1.23
1.26
V
External FET Gate Drive
DRVN High Level
VDRVN(H)
100mA from DRVN to GND
VCC -0.5 VCC -0.2
V
DRVN Low Level
VDRVN(L)
-100mA from DRVN to VCC
0.2
0.5
V
DRVN On-Resistance
RDRVN
DRVN High or Low
2
5
Ω
DRVN Sink / Source Current
IDRVN
DRVN Forced to 2.5V
1
A
Boost Converter
CS Current Limit Threshold
Soft-Start Time (1)
VCS(ILIM)
tSS
0.36
From EN to End of Soft-Start
0.40
4.4
0.44
V
ms
SC5014
Electrical Characteristics (continued)
Parameter
Symbol
Conditions
Min
Typ
Max
Units
Boost Oscillator Frequency
FSW
RFSET = 100kΩ
0.85
1
1.15
MHz
Boost Oscillator Frequency
FOSC
RFSET Varies
0.2
2.2
MHz
Maximum Duty Cycle
DMAX
88
92
%
Control Signals: EN, PWMI, SDA, SCL
High Voltage Threshold
VIH
VCC = 4.5V to 5.5V
Low Voltage Threshold
VIL
VCC = 4.5V to 5.5V
0.8
V
VSDA(L)
-6mA from VCC to SDA
0.3
V
ILEAK
VEN = 0V, VPWMI = VISET = VFSET = VSDA = VSCL = 5.0V
-1
1
µA
100
30k
Hz
SDA Output Low
Pin Leakage Current
2.1
V
PWM Dimming Input
PWMI Input Dimming Frequency
FPWMI
PWMI Input Resolution
100Hz < FPWMI < 10kHz
10
bits
10kHz < FPWMI < 20kHz
9
bits
Over-Voltage Protection
OVP Trip Threshold Voltage
VOVP(TRIG)
OVP Rising
1.1
1.2
1.3
V
OVP Hysteresis
VOVP(HYS)
OVP Falling
10
OVP Leakage Current
IOVP(LEAK)
OVP = 5V
0.1
TPWM(MIN)
FPWM(LED) = 100Hz - 30kHz
300
ns
1.23
V
0.9
V
mV
1
µA
Current Sink (IO1 to IO4)
IOx Dimming Minimum Pulse Width
ISET pin Voltage
VISET
Regulation Voltage
VIOn(REG)
Voltage of Regulating String
Current Sink Disable Threshold
VIOn(DIS)
Checked at Power-up
Current Sink Rise/Fall Time (1)
tRISE/FALL
Rising Edge from 10% to 90% of IO(n)
LED Current Accuracy
IOn(ACC%)
PWMI = 100%, TA=+25 °C
LED Current Matching (2)
IOn(MATCH)
IOn Off Leakage Current
IOn(LEAK)
IO Switching Frequency
FPWM(IO)
Phase Delay Time Between IO Pins
(IO1 to IO4)
PWM Output Resolution
tPD
0.6
V
25
98
100
ns
102
mA
PWMI = 100%, TA=+25 °C
±1.0
%
PWMI = 100%, TA=-40 °C, +85 °C
±2.0
%
1
µA
PWMI = 0V, EN = 0V, VIO1 = 25V
0.1
FAST_FREQ = 0
10
FAST_FREQ = 1 (Default Setting)
20
FAST_FREQ = 1 (Default Setting)
tPD = (1/4)*(1/FPWM(IO)), 4 Strings On
12.5
FPWM(IO) = 10kHz
10
FPWM(IO) = 20kHz
9
kHz
µs
bits
SC5014
Electrical Characteristics (continued)
Parameter
Symbol
Conditions
LED Short-Circuit Protection Threshold
VIOn(SCP)
R4 and R5 (3)
LED Open-Circuit Protection Threshold
VIO_OCP
Min
Typ
Max
Units
23xVSCP
V
Fault Protection
LED Short-Circuit Fault Delay
tSCP(DELAY)
VOVP Set to 1.5V, FLT Goes Low
FLT Pin Leakage Current
IFLT(LEAK)
VEN = 0V, VFLT = 5.0V
FLT Output Low
VFLT(LOW)
-5mA from FLT to VCC
17xVSCP 20xVSCP
0.2
V
1
µs
-1
1
µA
0.3
V
Over-Temperature Protection
Thermal Shutdown Temperature
TOTP
150
°C
Thermal Shutdown Hysteresis
TOTP-H
10
°C
I2C Control Interface: SDA, SCL Timing Specifications
SCL Clock Frequency
FSCL
SCL Clock Low Period
tLOW(SCL)
1.3
µs
SCL Clock High Period
tHIGH(SCL)
0.6
µs
Hold Time Start Condition
tHD(START)
0.6
µs
SDA Setup Time
tSU(SDA)
100
ns
SDA Hold Time
tHD(SDA)
0
Setup Time Stop Condition
tSU(STOP)
0.6
µs
tBF
1.3
µs
Bus Free Time Between Stop & Start
400
0.9
kHz
µs
Notes:
(1) Ensured by design and characterization, not production tested.
(2) LED current matching for 4 channels is defined as the largest of the two numbers, i.e., (MAX-AVG)/AVG and (AVG-MIN)/AVG; where MAX is the
maximum LED channel current, MIN is the minimum LED channel current and AVG is the average of the 4 LED channel currents.
(3) Refer to the application circuit on page 23, Figure 2.
BacklightEfficiencyvs.InputVoltage
SC5014
BacklightEfficiencyvs.InputVoltage
Typical Characteristics
˕˴˶˾˿˼˺˻̇ʳ˘˹˹˼˶˼˸́˶̌ʳ̉̆ˁʳ˜́̃̈̇ʳ˩̂˿̇˴˺˸
Backlight Efficiency vs. Input Voltage
˕˴˶˾˿˼˺˻̇ʳ˘˹˹˼˶˼˸́˶̌ʳ̉̆ˁʳ˜́̃̈̇ʳ˩̂˿̇˴˺˸
Backlight Efficiency vs. Input Voltage
10S4P
˄˃˃
120mA/CH
˄˃˃
7S4P
120mA/CH
ˌˈ
ˉ˃̀˔
ˌ˃
˄˅˃̀˔
Efficiency(%)
60mA/CH
˘˹˹˼˶˼˸́ ˶̌ ʻʸ ʼ
˘Efficiency(%)
˹˹˼˶ ˼˸ ́ ˶ ̌ ʻʸ ʼ
ˌˈ
ˋˈ
10S4P
ˊ
ˌ˃
˄
ˋˈ
BacklightEfficiencyvs.LEDstringCurrent
BacklightEfficiencyvs.LEDstringCurrent
ˋ˃
ˋ˃
˃
ˈ
˄˃
˄ˈ
˅˃
VIN(V)
˅ˈ
ˆ˃
˃
˩˜ˡʻ˩ʼ
Backlight Efficiency vs. LED String Current
60mA/CH
ˉ˃̀˔
˄˅˃̀˔
ˊˈ
Efficiency(%)
˘˹˹˼˶˼˸́˶̌ʻʸʼ
Efficiency(%)
˘˹˹˼˶˼˸́˶̌ ʻʸ ʼ
ˋ˃
ˊ˃
˅ˈ
ˆ˃
120mA/CH
60mA/CH
ˋˈ
ˉ˃̀
ˋ˃
˄˅˃
ˊˈ
ˊ˃
ˉˈ
˃
PWMDimmingLinearitywithPhaseShift
˅˃
ˇ˃
ˉ˃
ˋ˃
LED
PWM Dimming Duty Cycle (%)
˟˘˗ʳˣ˪ˠʳ˗˼̀̀˼́˺ʳ˗̈̇̌ʳ˖̌˶˿˸ʳʻʸʼ
ˉˈ
˄˃˃
˃
PWM Dimming Linearity with Phase Shift
˅˃
ˇ˃
ˉ˃
ˋ˃
PWMDimmingLinearitywithPhaseShift
LED
PWM Dimming Duty Cycle (%)
˟˘˗ʳˣ˪ˠʳ˗˼̀̀˼́˺ʳ˗̈̇̌ʳ˖̌˶˿˸ʳʻʸʼ
˄˃˃
PWM Dimming Linearity with Phase Shift
ˣ˪ˠʳ˗˼̀̀˼́˺ʳ˟˼́˸˴̅˼̇̌ʳ̊˼̇˻ʳˣ˻˴̆˸ʳ˦˻˼˹̇˲ˉ˃̀˔˂˖˛
˅ˈ˃
˅˃
ˌ˃
120mA/CH
ˋˈ
˄ˈ
VIN(V)
˩˼́ʻ˩ʼ
VIN=12V ˕˴˶˾˿˼˺˻̇ʳ˘˹˹˼˶˼˸́˶̌ʳ̉̆ˁʳ˜́̃̈̇ʳ˩̂˿̇˴˺˸ʳʻ˄˅˩˼́ʼ
ˌˈ
ˌ˃
˄˃
Backlight Efficiency vs. LED String Current
˕˴˶˾˿˼˺˻̇ʳ˘˹˹˼˶˼˸́˶̌ʳ̉̆ˁʳ˜́̃̈̇ʳ˩̂˿̇˴˺˸ʳʻˉ˩˼́ʼ
VIN=6V
ˌˈ
ˈ
60mA/CH, 10S4P, 20KHz Dimming
ˈ˃˃
˅˃˃
ˣ˪ˠʳ˗˼̀̀˼́˺ʳ˟˼́˸˴̅˼̇̌ʳ̊˼̇˻ʳˣ˻˴̆˸ʳ˦˻˼˹̇˲˄˅˃̀˔˂˖˛
120mA/CH, 10S4P,
20KHz Dimming
ˇ˃˃
˄˅˩˼́
˅ˇ˩˼́
˄˃˃
Iout
(mA)
˜ˢʻ̀˔ʼ
Iout
˜ˢʻ̀(mA)
˔ʼ
ˉ˩˼́
˄ˈ˃
ˉ˩˼́
ˆ˃˃
˄˅˩˼́
˅ˇ˩˼́
˅˃˃
˄˃˃
ˈ˃
˃
˃
˃
˅˃
ˇ˃
ˉ˃
ˋ˃
LED PWM Dimming
˗̈̇̌ʻʸʼ Duty Cycle (%)
˄˃˃
˃
˅˃
ˇ˃
ˉ˃
ˋ˃
˗̈̇̌ʻʸʼ Duty Cycle (%)
LED PWM Dimming
˄˃˃
LEDStringCurrentvs.RISET
SC5014
LEDStringCurrentMatchingvs.Temperature
Typical Characteristics (continued)
LED String Current vs. RISET
LED String Current Matching vs. Temperature
˦̊˼̇˶˻˼́˺ʳ˙̅˸̄̈˸́˶̌ʳ̉̆ˁʳ˥˜˦˘˧
VCC=5V, 120mA/CH
˄ˈ˃
LED String
Current (mA)
˜̂̈̇ʻ̀˔ʼ
LED
String
Current
Matching
˟˘˗ʳ˦̇̅˼́
˺ ʳ˖̈
̅̅˸ ́ ̇ʳˠ˴
̇˶ ˻ ˼́ ˺ ʻʸ ʼ(%)
˃ˁˋ
˃ˁˉ
˃ˁˇ
˃ˁ˅
˄˅˃
ˌ˃
ˉ˃
ˆ˃
˃
˃ˁ˃
ˀˇ˃
ˀ˅˃
˃
˅˃
ˇ˃
Temperature
˧˸̀̃˸̅˴̇̈̅˸ʻкʼ (°C)
ˉ˃
ˋ˃
˃
˄˃˃
˦̊˼̇˶˻˼́˺ʳ˙̅˸̄̈˸́˶̌ʳ̉̆ˁʳ˥˙˦˘˧
Switching Frequency vs. RFSET
˅˃
ˇ˃
LED
String
Current
Accuracy
(mA)
˟˘˗ʳ˦̇̅˼́
˺ ʳ˖̈
̅̅˸ ́ ̇ʳ˔˶
˶ ̈ ̅˴ ˶ ̌ ʳʻ˩ʼ
˄˅ˇ
˅˃˃˃
˄ˉ˃˃
˄˅˃˃
ˋ˃˃
ˇ˃˃
˄ˈ˃
ˆ˃˃
RFSET(KΩ)
AnalogDimming
ˋ˃
RISET
(KΩ)
˥˜˦˘˧
ʻ˞Өʼ
VCC=5V, 120mA/CH
˄˃˃
˄˅˃
˄ˇ˃
ˇˈ˃
˄˅˃
˄˄ˋ
˄˄ˉ
ˀˇ˃
ˉ˃˃
˜ˢˆ
˄˅˅
˄˄ˇ
˃
˃
ˉ˃
LED String Current Accuracy vs Temperature
˅ˇ˃˃
˙˦ʻ˞˛̍
ʼ
Boost Switching
Frequency
(KHz)
CurrentAccuracyvs.Temperature
LEDStringCurrentvs.RISET
ˀ˅˃
˥˙˦˘˧ʻ˞Өʼ
˃
VINStartUP
˅˃
ˇ˃
ˉ˃
Temperature
˧˸̀̃˸̅˴̇̈̅˸ʳʻкʼ (°C)
ˋ˃
˄˃˃
VIN Start Up
LED String Current vs. Analog Dimming Control
Register (IDAC) Value
Testing condition: VIN=12V,VCC=5V, LEDs=10S4P@120mA,
RFSET=100KӨ
Ө, 25к
к
10S4P, 120mA/CH
125
LED String
Current (mA)
ILED(mA)
Vin
100
VIN
10V/div.
75
IO1
50
25
0
0
4
8
12
16
20
24
IDAC Register Value
DEC(in decimal format)
28
32
VSW
20V/div.
SW
Vout
VOUT
20V/div.
IOUT
300mA/div.
Iout
Time (20ms/div)
SC5014
LEDCurrentFadeIn/Out(Logarithmic)
Fadein/Fadeout(Linear)
Typical Characteristics (continued)
Testing condition: VIN=12V, 25к
к, LEDs=10S4P@120/CH,PWM indirect
Testing condition: VIN=12V, 25к
к, LEDs=10S4P@120/CH,PWM indirect
mode; PWM=10KHz, PWMI on / off, duty=0% to 100%
mode; PWM=10KHz, PWMI on / off, duty=0% to 100%
LED
Current Fade In/Out (Logarithmic)
PWMI
5V/div.
LED Current Fade In/Out (Linear)
PWMI
V_IO4
VIO1
10V/div.
PWMI
5V/div.
PWMI
V_IO4
VIO1
10V/div.
Vout
VOUT
20V/div.
Vout
VOUT
20V/div.
LineTransientResponse
IOUT
200mA/div.
Time (100ms/div)
Iout
IOUT
200mA/div.
Line Transient Response
LEDsOpen-circuitProtection
Iout
Time (100ms/div)
LED Open Circuit Protection
Test condition: 8Vin to 20Vin, 10S4P@120mA per string, RFSET=100KӨ
Ө,
Vin RT=1us
Testing condition: VIN=12V, 25к
к, LEDs=10S4P@120mA/CH, CH4 open,
RFSET=100KHz, ROVP2=357KӨ
Ө
100% dimming, 120mA/CH X 4
Starting with one LED string open-circuit
20V
EN
PWMI
VIN
10V/div.
8V
VOUT
1V/div.
Vout
VIO1
1V/div.
VEN
5V/div.
FLT
5V/div.
FLT
V_IO4
Vout
VOUT
20V/div.
IL
3A/div.
Iout
IL
IOUT
200mA/div.
LoadTransientResponse
Time (4us/div)
Load
Transient кResponse
Testing condition: VIN=12V, 25к
, LEDs=10S4P@120mA/CH,
LoadTransientResponse
Time (20ms/div)
Load
Transient кResponse
Testing condition: VIN=12V, 25к
, LEDs=10S4P@120mA/CH,
PWMI(10KHz)=2%
to 98%,PWMI=10K,
VIN=12V,
120mA/CH
X4
RFSET=100KHz,
Duty=2%
to 98%
Fading disabled
PWMI(10KHz)=98%
to 2%,PWMI=10K,
VIN=12V,
120mA/CH
X4
RFSET=100KHz,
Duty=98%
to 2%
Fading disabled
PWMI
PWMI
5V/div.
PWMI
5V/div.
PWMI
Vout
VOUT
200mV/div.
Iout
VOUT
200mV/div.
IOUT
200mA/div.
Vout
IOUT
200mA/div.
Iout
Time (100us/div)
Time (100ms/div)
SC5014
LEDDimmingWithoutPhaseShift
LEDDimmingWithPhaseShift
Typical Characteristics (continued)
Testing condition: VIN=12V, 25к
к, LEDs=10S4P@120mA/CH,
Testing condition: VIN=12V, 25к
к, LEDs=10S4P@120mA/CH,
LED Dimming
Phase Shift
RFSET=100KHz,Without
PWMI=200HZ, Duty=10%
LED Dimming
With Phase
RFSET=100KHz, PWMI=200HZ,
Duty=10% Shift
10% dimming@200Hz, VIN=12V, 4P10S, 120mA/CH
10% dimming@200Hz, VIN=12V, 4P10S, 120mA/CH
V_IO1
VIO1
10V/div.
VIO2
10V/div.
V_IO2
IL
1A/div.
IL
IOUT
400mA/div.
Iout
VIO1
10V/div.
VIO2
10V/div.
V_IO1
V_IO2
IL
1A/div.
IL
IOUT
400mA/div.
LEDDimmingWithoutPhaseShift
Iout
LEDDimmingWithPhaseShift
Time (2ms/div)
Time (2ms/div)
Testing condition: VIN=12V, 25к
к, LEDs=10S4P@120mA/CH,
LED Dimming
Without
Phase
RFSET=100KHz,
PWMI=200HZ,
Duty=35% Shift
condition: VIN=12V, 25к
к, LEDs=10S4P@120mA/CH,
LEDTesting
Dimming
With
Phase
Shift
RFSET=100KHz,
PWMI=200HZ,
Duty=35%
35% dimming@200Hz, VIN=12V, 4P10S, 120mA/CH
35% dimming@200Hz, VIN=12V, 4P10S, 120mA/CH
VIO1
10V/div.
VIO1
10V/div.
VIO2
10V/div.
V_IO1
V_IO2
IL
1A/div.
IL
V_IO1
VIO2
10V/div.
V_IO2
IL
1A/div.
IL
Iout
IOUT
400mA/div.
IOUT
400mA/div.
AnalogDimmingTransientviaI2C
AnalogDimmingTransientviaI2C
Time (2ms/div)
Time (2ms/div)
Testing condition: VIN=12V, 25к
к, LEDs=10S4P@120mA/CH,
Analog
Dimming
Transient
via I2C
RFSET=100KHz, 60mA/CH to 120mA/CH
Testing condition: VIN=12V, 25к
к, LEDs=10S4P@120mA/CH,
Analog
Dimming
Transient
via I2C
RFSET=100KHz, 120mA/CH
to 60mA/CH
60mA/CH to 120mA/CH
VSDA
5V/div.
120mA/CH to 60mA/CH
SDA
VSW
20V/div.
SW
Vout
VOUT
2V/div.
IOUT
300mA/div.
Iout
Iout
VSDA
5V/div.
SDA
VSW
20V/div.
SW
VOUT
2V/div.
IOUT
300mA/div.
Vout
Iout
Time (40us/div)
Time (40us/div)
SC5014
Pin Descriptions
Pin #
(QFN)
Pin
Name
1
UVLO
Pin Function
Input under-voltage lockout pin — Device is disabled when this pin is less than 1.23V (nominal). Add a resistor
divider from this pin to the input voltage and AGND, respectively.
2
SCP
Short-circuit LED protection programming pin — Shorted LED protection disables the individual channel when the
current sink voltage exceeds the programmed voltage threshold. Adding a resistor divider from this pin to REF and
PGND programs the shorted-LED protection up to 20x the VSCP voltage. Pulling the pin high to VCC disables the SCP
feature on all channels.
3
REF
1.23V reference voltage output pin — Connect a 1µF ceramic bypass capacitor from this pin to ground.
4
FSET
Step-up (boost) frequency set pin — Connect a resistor from this pin to ground to set the frequency from 200kHz to
2.2MHz.
5
CPLL
Compensation for the internal PLL — Connect a compensation resistor and capacitor from this pin to ground. This
pin can be left floating if not used.
6
SCL
I2C serial clock input — This pin must be connected to ground if not used.
7
SDA
I2C serial data input — This pin must be connected to ground if not used.
8
ISET
LED current programming pin — Connect an external resistor to ground to program the current in the LED strings.
For more details please refer to LED String Peak Current Programming on page 13.
9
FLT
Logic low fault status pin — Open-drain output is latched low when fault condition is detected: Open/Short LED,
Shorted String, OVP or OTP. Fault status can be reset by removing fault condition(s) and toggling the EN, VCC or
UVLO pins. This pin can be left floating if not used.
10
PWMI
11 ~14
IO4 ~ IO1
Regulated current sink LED channel 4 to channel 1 respectively — Connect the related IO pin to the cathode of
the bottom LED in string 4 to string 1 respectively. Connect the related IO pin to ground to disable the related LED
string during power on.
15
OVP
Over-voltage feedback pin — Over-voltage activated when pin voltage exceeds 1.2V. Use a resistor divider tied to
the output and GND to set the OVP level.
16
CS
17
PGND
Power ground — Tie this pin to the power ground plane close to input and output decoupling capacitors.
18
NDRV
Gate drive for the external step-up (boost) N-Channel MOSFET.
19
VCC
Input bias voltage supply for the IC — Accepts 4.5-5.5V inputs. Add a 1µF or larger ceramic bypass capacitor from
this pin to ground.
20
EN
Logic high enable pin — Pull logic high to enable the device or pull low to disable and maintain low shutdown
current.
-
PAD
AGND thermal pad for heatsinking purposes — It should be connected to ground plane for proper circuit operation.
LED string PWM dimming control input.
Step-up (boost) switch current sense pin — Connect a resistor from this pin to ground for current sense - utilized in
peak current mode control loop and over-current sense circuitry.
10
SC5014
Block Diagram
REF
FSET
SCP
VBG
X20
OVP
-
OVP
CPLL
+
SC_REF
PLL
CP
VCO
BG
Boost
Oscillator
OSC
1/N
18
VCC
PWMI
UVLO
EN
I2C
(PLLrange)
LS
ControlLogic
NDRV
OTP
10MHz
(SystemClk)
PWMFreq.
Adjust
CLIM
PWM
COMP
8
DC
-
+ - +
Slope
Comp
CS
COMP
DutyCycle
Extractor
+
ILIM
Recycle
Generator
EA
4
+
DC
-
MinimumVoltage
Detection
4
10
DutyCycle
MUX
4
OC/SC
Detection
IO2
LEDOpen/ShortFault
I2C
Interface
SDA
SCL
FLT
10
2
I CInterface
and
LEDControl
Logic
IO3
4
LEDFreqAdjust
PWMDimAdjust
ISETAdjust
IO1
SC_REF
5
5-bit
DAC
IO4
I-REF
ADJ
OTP
ISET
PGND
11
SC5014
Applications Information
General Description
The SC5014 contains a high frequency, current-mode,
internally compensated boost controller with 4 constant
current sinks for driving LED strings. The LED current for
all strings is programmed by an external resistor. The boost
converter operates to maintain minimal required output
voltage for regulating the LED current to the programmed
value. A typical backlight application uses 3 to 14 LEDs
per each string, with current driven up to 120mA. The
unique control loop of the SC5014 allows fast transient
response in dealing with line and load disturbances. The
SC5014, operating with an external power MOSFET, regulates the boost converter output voltage based on the
instantaneous requirement of the 4 string current sources.
This provides power to the entire lighting subsystem with
increased efficiency and reduced component count. It
supports PWM dimming frequencies from 100Hz to 30kHz
and the supply current is reduced to 2mA typical when all
LED strings are off.
Start-Up
When the EN pin is pulled up high (>2.1V), the device is
enabled and the UVLO and VCC pin voltages are checked.
The VCC voltage has fixed under-voltage rising and falling
trip points. If the VCC pin is higher than 4.2V and the UVLO
pin voltage is greater than 1.23V, the SC5014 goes into a
start-up sequence. The UVLO pin voltage can be used to
program the input power source voltage VIN turn-on
threshold and its hysteresis (refer to the detailed application circuit on page 23, Figure 2) as shown by the following equations:
VIN_TurnOn [V] = 1.23 X (R1 + R2) / R1
VIN_Hysteresis [V] = 10-5 X R2 [Ω]
In the next phase, the SC5014 checks each IO pin to determine if the respective LED string is enabled. Each IO pin is
pulled up with a 100µA current source. If any IO pin is connected to ground, it will be detected as an unused string,
and will be turned off. This unused string checking procedure typically takes 1ms. After this, the SC5014 enters into
a soft-start sequence.
The soft-start function helps to prevent excess inrush
current through the input rail during start-up. In the
SC5014, the soft-start is implemented by slowly ramping
up the reference voltage fed to the error amplifier. This
closed loop start-up method allows the output voltage
to ramp up without any overshoot. The duration of the
soft-start in the SC5014 is controlled by an internal timing
circuit, which is used during start-up and is based on the
boost converter switching frequency. For example, with
switching frequency at 1MHz, it is 8ms typical and
becomes 4ms typical when the switching frequency is
2MHz.
If the PWM voltage goes low while the SC5014 is in softstart operation, the SC5014 switches to standby mode,
where the external power MOSFET and the LED current
sources will be turned off immediately. The internal softstart timer is turned off and the soft-start value is saved.
When the PWM voltage goes high again, the soft-start
resumes from the previously saved value.
Each LED current source (IO1 to IO4) tries to regulate the
LED current to its set point. The control loop will regulate
the output voltage such that all the IO pin voltages are at
least 0.9V typical.
Shutdown
When the EN pin is pulled down below 0.8V, the device
enters into shutdown mode. In this mode, all the internal
circuitry is turned off and the supply current is less than
1µA (max).
In the scenario where the EN pin voltage is high, but VCC
voltage falls below the respective UVLO threshold, the
SC5014 goes into a suspend mode. In this mode, all the
internal circuitry except the reference and the oscillator
are turned off.
Thermal Shutdown (TSD)
If the thermal shutdown temperature of typical 150°C is
reached, the boost converter and all IO current sources
are turned off. The FLT pin is forced low in this condition.
When the temperature falls below the TSD trip point by
10°C, the SC5014 will restart following the start-up
sequence as described before. The FLT pin is latched and
will stay low, it is reset by cycling the EN, VCC or UVLO.
12
SC5014
Applications Information (continued)
Boost Converter Operation
The SC5014 includes a boost controller with programmable switching frequency. It applies a current-mode control
method with an integrated compensation loop as shown
in the diagram below. The clock (see block diagram on
page11) from the oscillator sets the latch and turns on the
external power MOSFET, which serves as the main power
switch. The current flowing through this switch is sensed
by the current sense resistor in series with the switch. The
sensed switch current is summed with the slope-compensated ramp and fed into the modulating input of the
PWM comparator. When the modulating ramp intersects
the error amplifier output (COMP), the latch is reset and
the power MOSFET is turned off. The sense resistor also
sets the peak current limit of the power MOSFET, IOCP using
the following equation:
IOCP[A] = 0.4 / RCS [Ω]
VIN=4.5to27V
OSC
Control
Logic
LS
NDRV
Q1
When the OVP pin voltage exceeds 1.2V, the boost converter turns off and the FLT pin is pulled low. When the
OVP pin voltage falls below the OVP threshold (falling),
the boost converter restarts and the FLT pin is released.
There is 10mV hysteresis between the OVP pin threshold
(falling) and the OVP pin threshold (rising). This results in
an output voltage hysteresis expressed as:
CS
LED Current Sink
The SC5014 provides 4 current sinks and each can sink up
to 120mA current. It incorporates LED string short-circuit
protection (trip-level programmable; can be disabled)
and LED string open-circuit protection.
C5
RCS
+ - +
COMP
+
EA
-
DC
IO
Min.Voltage
Detection
The current-mode control system contains two loops. For
the inner current loop, the error amplifier (EA) output
(COMP) controls the peak inductor current. In the outer
loop, the EA regulates the output voltage for driving the
LED strings.
Boost Converter Switching Frequency Selection
The resistor between FSET and GND sets the boost converter switching frequency (200kHz to 2.2MHz) using the
following equation:
OVP Trip Voltage [V] = 1.2 X (R11 + R12) / R12
Output OVP Hysteresis [mV] = 10 X (R11 + R12) / R12
PWM
COMP
Slope
Comp
L1
D1
Boost
Oscillator
Over-Voltage Protection (OVP)
The SC5014 features programmable output over-voltage
protection to prevent damage to the IC and output capacitor in the event of a LED string open-circuit. The boost converter output voltage is sensed at the OVP pin through the
resistor voltage divider. The OVP trip threshold (refer to
detailed application circuit on page 23, Figure 2) can be calculated using the following equation:
fSW [kHz] = 105/ RFSET [kΩ]
LED String Peak Current Programming
LED string peak current (at 100% dimming) can be set by
selecting resistor RISET, connected between ISET and GND.
The relationship between RISET resistance and single LED
string peak current is calculated using the following
equation:
ILED [mA] = 2 X (1036 X 1.23) / RISET [kΩ]
The string current can be programmed up to 120mA.
Unused Strings
The SC5014 may be operated with less than 4 strings. In
this mode of operation, all unused IO pins should be connected to ground. During start-up, these unused strings
are detected and disabled while other active strings work
normally, and FLT does not get pulled low.
A higher switching frequency allows the use of low-profile
height inductors for space-constrained and cost-sensitive
applications.
13
SC5014
Applications Information (continued)
LED Short-Circuit Protection (SCP)
The SC5014 features a programmable LED short-circuit
protection (SCP). This allows the part to be customized
based on the LED forward voltage (VF) mismatches between
the LED strings. If one or more LEDs are detected as shortcircuited, the corresponding string will be latched off. The
voltages on all IO pins are monitored to check if any IO pin
exceeds the SCP trip point. The IO voltage for LED string(s)
with faulty short-circuit LED(s) will be higher than other
normal IO pin voltages. This LED short-circuit protection
trip level (see detailed application circuit on page 23,
Figure 2) is expressed by the following equation:
VSCP_Trip [V] = 20 X (1.23 X R4) / (R4 + R5)
If any IO pin voltage exceeds the trip voltage, the IO current
sink will be latched off and the FLT will go low. This latch can
be reset by cycling UVLO, VCC or EN. Other LED strings are
unaffected and continue in normal operation. This protection will be disabled if SCP is tied to VCC.
There is a typical 10μs SCP detection time in PWM dimming
applications. If the PWM dimming on-time is less than the
SCP detection time, the SCP cannot be enabled.
In many applications, LED strings are connected to the IO
pins through a mechanical connector, which cannot support
an electrical connection at specific times. This connection
PWM
Input
DutyCycle
Extractor
ExtractedDuty
Cyclefrom
PWMIInput
10
10
might cause noise on the IO pins. If this noise is large
enough, it may trigger a false SCP mode. Under such condition, a ceramic decoupling capacitor (100pF ~ 8.2nF)
between IO pin to ground can help prevent the SC5014
from entering the protection mode by false trigger. Or,
simply disable this feature by connecting SCP pin to VCC
pin.
LED Open-Circuit Protection
If any LED string becomes open, the respective IO pin
voltage will be pulled to ground. Consequently, the internal COMP node (output of error amplifier) is driven high,
which causes the boost output voltage to increase. The
output voltage will be eventually clamped to a voltage
set by the OVP resistor divider. Under this condition, the
faulty string is latched off and the FLT pin is pulled low.
The boost voltage gets regulated to the voltage required
to set all non-faulty IO pins above 0.9V (typ). The remaining strings remain in normal operation. The FLT and the
fault-out LED current sink latch-off can be reset by cycling
UVLO, VCC or EN.
LED Analog Dimming Control
The LED current in SC5014 can be dimmed via the 5-bit
analog dimming register (register address: 0x02). The LED
current can be adjusted in 32 steps from 0mA to maximum
value, which is determined by the RISET resistor.
LEDFrequencyandPhase-ShifterBlock
0
PWM
Input
10
PWM
Generator
1
0
PhaseShifting
4
EN
1
PWM[4:1]
4
PWM_ps[4:1]
1
Allbitsidentical
whenphase
shiftingdisabled
8
Soft-Start
D[9:0]Bits
INT_DUTYBit
FREQBits
FastFreqBit
PH_SHIFTBit
INT_PWMBit
I2CInterface
Figure 1— LED PWM Dimming Control
14
SC5014
Applications Information (continued)
The SC5014 has a unique DAC architecture which allows it
to have excellent LED current accuracy and string-to-string
matching over the entire DAC range.
The analog dimming method can be used in conjunction
with PWM dimming to increase the dimming resolution.
The fast loop response of the SC5014 allows the LED
current to transition to a new value within 160µs or so.
Please refer to the graphs in the typical characteristics
section.
LED PWM Dimming Control
The SC5014 supports three PWM dimming modes for
controlling the brightness of the LEDs.
The dimming modes are:
(1) PWM direct,
(2) PWM indirect and
(3) I2C control
It provides flexibility in setting the duty cycle and frequency of the LED PWM signal. The PWM dimming mode
is set through the device control register (register address:
0x01) DCR [1:0] bits. Refer to Table 1 for more details.
(1) PWM Direct Control
The PWM input needs to be held high for normal operation. PWM dimming can be achieved by cycling the PWM
input at a given frequency where a “low” on the PWM
input turns off all IO current sinks and a “high” turns on all
IO current sinks. The PWM pin can be toggled by external
circuitry to allow PWM dimming. In a typical application,
a microcontroller sets a register or counter that varies the
pulse width on a GPIO pin. The SC5014 allows dimming
over a wide frequency range (100Hz-30kHz) in order to
allow compatibility with a wide range of devices. This
includes the newest dimming strategies that avoid the
audio band by using high frequency PWM dimming. In
this manner, a wide range of illumination can be generated while keeping the instantaneous LED current at its
peak value for high efficiency and color temperature. The
SC5014 provides a 1000:1 dimming range at 1kHz PWM
frequency. The LED current sinks turn on/off very rapidly
(<25ns, typical). This allows a wide dimming ratio. An additional advantage of PWM dimming is that it avoids in-rush
currents when filling the boost output capacitor. Simply
apply the PWM signal to the device at 10% duty for a millisecond or two, and in-rush current is reduced. This
dimming time will vary based on the number of LEDs and
the size of the output capacitor. This can be easily determined during testing and programmed into the microcontroller firmware.
Table 1 — LED Dimming Control Methods
PWM Dimming Mode
Register
Settings
DCR[1:0]
PWM
Input
Source
PWM Frequency
PWM Duty Cycle
Phase
Shift
Option
PWM Direct
Control
00
PWMI Pin
Input
Same as the PWMI Input
(Range 100 Hz to 30kHz)
Same as the PWMI Input
NO
01
PWMI Pin
Input
Set via the FREQ Register
(0x05) and FAST_FREQ Bit
10kHz (max): FAST_FREQ=0
20kHz (max): FAST_FREQ=1
Same as the Duty Cycle of the PWM Input
YES
11
I2C
Control
Set via the FREQ Register
(0x05) and FAST_FREQ bit
10kHz (max): FAST_FREQ=0
20kHz (max): FAST_FREQ=1
Set Via the Duty Cycle Control
Register (0x03, 0x04)
10-Bits @ 10kHz Output
9-Bits @ 20kHz Output
YES
PWM Indirect
Control
(Default
Option)
I2C
Control
LED PWM Output
15
SC5014
Applications Information (continued)
(2) PWM Indirect Control
This is the default mode for LED PWM dimming in the
SC5014. In this mode, the input signal applied on the PWM
pin is passed through a duty cycle extractor block after the
system has detected two successive duty cycles that are the
same. The extractor measures the duty cycle of the PWM
input, and, depending on the value of FAST_FREQ, the duty
cycle is converted to a 9-bit value (FAST_FREQ = 1) or a 10bit value (FAST_FREQ = 0). This value is then passed to the
PWM generator block as shown in Figure 1.
should be connected to ground. In this mode, the LED
dimming duty cycle is set via the duty cycle registers
(addresses 0x03, 0x04); and the dimming frequency is set
via the FREQ register (address 0x05) and the FAST_FREQ
bit.
With FAST_FREQ = 0, the LED duty cycle can achieve 10-bit
resolution, D[9:0], which is combined by two portions: (1)
MSB portion - register address 0x03 [1:0] and (2) LSB portion
- register address 0x04 [7:0] as shown below.
The LED PWM output frequency is set via the FREQ register (address 0x05) and the FAST_FREQ bit.
With FAST_FREQ = 0, low dimming frequency option is
selected and the PWM dimming frequency will be according to the following equation:
10MHz
1024 × [FREQ[7 : 0] + 1]
= 10kHz(max)
PWM Dimming Frequency =
With FAST_FREQ = 1, the high dimming frequency option
is selected and the PWM dimming frequency is shown by
the following equation:
10MHz
512 × [FREQ[7 : 0] + 1]
= 20kHz(max)
PWM Dimming Frequency =
The default option is FAST_FREQ = 1. This gives 9-bit duty
cycle resolution and up to 20kHz dimming frequency
range. The PWM input is usually generated by the system
graphics processor. This mode allows the user to set the
PWM output dimming frequency independent of the
PWMI input.
If the PWM signal has jitter, the SC5014 provides an option
to filter it out. Hysteresis is also provided by selecting the
WND[1:0] bits in the DCR register (address 0x01). WND[1:0]
bits set the window comparator such that if a change in
the duty cycle is detected which is smaller than the set
window, then it is ignored.
The dimming duty cycle with FAST_FREQ = 0 can be calculated as:
LED Dimming Duty Cycle = {D[9:0]decimal }/210-1
With FAST_FREQ = 1, the LED duty cycle can achieve 9-bit
resolution, D[9:1], which is combined by two portions: (1)
MSB portion - register address 0x03 [1:0] and (2) LSB portion
- register address 0x04 [7:1] as shown below.
The dimming duty cycle with FAST_FREQ = 1 can be calculated as:
LED Dimming Duty Cycle = {D[9:1]decimal }/29-1
In both cases mentioned above, the duty cycle is fixed to be
0 when D[9:0] is set as 0x00.
The PWM dimming frequency is controlled the same way as
in “Indirect Control”.
(3) I2C Control
In I2C dimming mode (refer to Figure 1, page 14), both the
output LED dimming duty cycle and the dimming frequency are set via the internal registers. The PWMI pin
16
SC5014
Applications Information (continued)
Phase-Shift PWM Dimming
The SC5014 provides an option for phase-shifted LED PWM
dimming. This option is available in both PWMI indirect
control and I2C control. The phase-shift option is set by the
PH_SHIFT bit in the Device Control Register (register address
0x01). This option delays the turn-on of the LED strings
based on the number of the strings in operation (the
number of the strings in operation is determined during
the start-up). The delay time can be calculated by the
following equation:
1
fPWM
,
N
N = number of strings in operation
Tφ −phase =
fPWM = LED PWM dimming frequency
An example for calculating the fading time is shown in
this section. Assuming LED PWM dimming frequency is
10kHz, then 10-bits are assigned for 1024 duty cycle
settings.
Table 2 — Fade Setting
Duty
Cycle
Zone
Duty Cycle
Range
Step
Increment
Step
Interval
Total Steps
within the
Range
1
2
3
0 to 511
512 to 767
768 to 1024
1
1
2
2
1
1
512
256
256
The time required to go from 10% (102/1024) to 90%
(922/1024) duty cycle can be calculated using the following equation:
Phase-shift mode is disabled during the soft-start period.
This allows the output to ramp up to the correct voltage in
a controlled fashion.
TPWM = 100 µs (with 10kHz dimming frequency)
Phase-shifting reduces the peak input current, decreases
EMI and improves the dimming linearity. The figures in the
Typical Characteristics Section on page 6 show the
improvement in dimming linearity with phase-shifted
versus non-phase-shifted dimming.
Cycle in Zone #2 = Total Steps in Zone #2 x [(Zone #2 Step
Interval) / (Zone #2 Step Increment)]
Backlight Fade-in and Fade-out Options
The SC5014 features an option for fade-in and fade-out
brightness control, which allows a smooth transition from
one brightness level to another.
Cycle in Zone #1 = (511 - Starting Duty Cycle) x [(Zone #1
Step Interval) / (Zone #1 Step Increment)]
Cycle in Zone #3 = (End Duty Cycle - 768) x [(Zone #3 Step
Interval) / (Zone #3 Step Increment)]
In this case, the total cycle will be:
Registers associated with these fading functions are
shown in this section.
Total cycle = 2 x (511-102) + 1 x 256 + 0.5 x (922 - 768)
= 1151
Total Fading Time = Total Cycle x TPWM
= 1151 x 100 µs = 115.1ms
. Fade Option (register address 0x09) — sets fade
enable options, fade time, fade type.
2. Fade Rate (register address 0x0A) — sets fade step
size option.
Time required to go from 10% (102/1024) to 90%
(922/1024) duty cycle can be calculated using the following equation:
The fade option register allows the user to select fading,
choose between linear or logarithmic fading, and to set
the fading time. The default setting is fading enabled with
logarithmic mode. The fading time is determined by the
LED PWM dimming frequency. The fade setting is shown
in Table 2.
TPWM = 100 μs (PWM Dimming Period)
1
Total Cycle = 2 × (511 − 102) + 256 + × (922 − 768) = 1151
2
Total Time = 1151× TPWM = 115.1ms
17
SC5014
Table 3 — Fault Protection Descriptions
Action on Fault
Type of
Fault
User
Disable?
Fault Criteria
Input
Under-voltage
at VIN
(UVLO)
No
Input
Under-voltage at VCC
(UVLO)
Recovery
Device
FLT pin (latching
/ non-latching
Condition(s)
FLT pin
VIN < (1 + R2/R1)
x 1.23 (rising)
No Startup
Not Active
VUVLO > 1.23V
(rising)
High
No
VIN < (1 + R2/R1) × 1.23V - IUVLO
× R1 (falling)
Shutdown
Not Active
VUVLO > 1.23V
(rising)
High
No
VCC < 4.2V
(rising)
No Startup
Not Active
VCC > 4.2V
(rising)
High
No
VCC < 4.0V
(falling)
Shutdown
Not Active
VCC > 4.2V
(rising)
High
Over-voltage
Protection
(OVP)
No
VOVP > 1.23V
(rising)
Regulate to OVP
threshold:
IO(n) = “on”
Low
(non-latching)
VOVP < 1.22V
(falling)
High on removal of fault
condition
Over-current
Protection
(OCP)
No
VCS > 0.4V
Limit Q1 FET drain
current < 0.4V/R9
(typ) (1)
High
VCS > 0.4V
High
VIO(n) > 20 x VSCP
Device on:
IO(n) = “off”
Other IO(All) = “on”
Low
(latching)
Replace Shorted
LED(s) and Toggle
EN, VCC or UVLO
High
VIO(All) > 20 x VSCP
Device latch-off;
IO(All) = “off”
Low
(latching)
Replace Shorted
LED(s) and Toggle
EN, VCC or UVLO
High
VIO(n) < 0.1V
and OVP event
Device on:
IO(n) = “off”
Other IO(All) = “on”
Low
(latching)
Replace Open
LED(s) and Toggle
EN, VCC or UVLO
High
VIO(All) < 0.1V
and OVP event
Device latch-off;
IO(All) = “off”
Low
(latching)
Replace Open
LED(s) and Toggle
EN, VCC or UVLO
High
VIO(All) < 0.1V
(start up)
Device on:
IO(n) = “off”
Other IO(All) = “on”
High
TJ > 150ºC (typ)
Device off;
IO(All) = “off”
Low
(latching)
Satisfy THYS > 10ºC;
Device On;
IO(All) = “on”;
Toggle EN, VCC or
High
Shorted
LED(s)
Open
LED(s)
Unused Strings
Over-Temperature Protection
(OTP)
Yes, tie
SCP to
VCC
No
No
No
Note: Refer to the application circuit example for R1 and R2 on page 23, Figure 2.
18
SC5014
Applications Information (continued)
Fault Protection
The SC5014 provides fault detection for low supply
voltage, LED related faults, boost converter over-voltage
and thermal shutdown. The open drain output pin (FLT)
indicates a system fault. The nature of the fault can be read
from the fault status resistor (register address: 0x00) via I2C
interface. Refer to Table 3 for a description of the Fault
Protection Modes.
Other Possible Configurations
Depending on different application requirements, the
SC5014 can also be easily configured to other topologies,
such as the SEPIC configuration shown in Figure 4, page
24.
Li-Ion Powered Display Configuration
If a Li-Ion powered display application is required, VCC is
needed to power with 5V. However, VIN can be set lower
from 3V to 4.2V for example. An advantage of this type of
configuration is that it provides higher efficiency. Please
use Figure 3 on page 23 for reference.
High Output Voltage Configuration
If a high output voltage application is required, an additional external cascode MOSFET can be added on each IO
pin to meet such requirement, please refer to Figure 5 on
page 24 for reference.
In this case, the upper limit on the output voltage is mainly
determined by the rating of the external MOSFET, heat
dissipation, etc.
PCB Layout Considerations
The placements of the power components outside the
SC5014 should follow the layout guidelines of a general
boost converter. The Detailed Application Circuit is used
as an example.
. Capacitor (C2) should be placed as close as possible to
the VCC and AGND to achieve the best performance.
3. The converter power train inductor (L1) is the boost
converter input inductor. Use wide and short traces
connecting these components.
4. The output rectifying diode (D1) uses a Schottky diode
for fast reverse recovery. Transistor (Q1) is the external
switch. Resistor (R9) is the switch current sensing resistor. To minimize switching noise for the boost converter, the output capacitor (C6) should be placed
such that the loop formed by Q1, D1, C6 and R9, is
minimized. The output of the boost converter is used
to power up the LEDs. Use wide and short trace connecting Pin NDRV and the gate of Q1. The GNDs for R9
and C6 should be PGND. These components should
be close to the SC5014.
5. Resistor (R8) is the output current adjusting resistor
for IO1 through IO4 and should return to AGND. Place
it next to the IC.
6. Resistor (R6) is the switching frequency adjusting
resistor and should return to AGND. Place it next to
the IC.
7. The decoupling capacitor (C3) for Pin REF should
return to AGND. Place it next to the IC.
8. Resistors (R4, R5) form a divider to set the SCP level, R4
should return to AGND. Place it next to the IC.
9. Resistors (R2, R1) form a divider to set the UVLO level
for UVLO pin. R1 should return to AGND. Place it next
to the IC.
0. R11 and R10 form a divider to set the OVP level for
VOUT, R10 should return to AGND. Place it next to the
IC.
. All the traces for components with AGND connection
should avoid being routed close to the noisy areas.
2. An exposed pad is located at the bottom of the SC5014
for heat dissipation and analog ground. A copper area
underneath the pad is used for better heat dissipation.
On the bottom layer of the PCB another copper area,
connected through vias to the top layer, is used for
better thermal performance. The pad at the bottom of
the SC5014 should be connected to AGND. AGND
should be connected to PGND at a single point for
better noise immunity.
2. Capacitor (C1) is the input power filtering capacitor for
the boost. It needs to be tied to PGND.
19
SC5014
Components Selection
Inductor Selection
The choice of the inductor affects the converter’s steady
state operation, transient response, and its loop stability.
Special attention needs to be paid to three specifications
of the inductor, its value, its DC resistance and saturation
current. The inductor’s inductance value also determines
the inductor ripple current. The boost converter will
operate in either CCM (Continuous Conduction Mode) or
DCM (Discontinuous Conduction Mode) depending on its
operating conditions. The inductor DC current or input
current can be calculated using the following equation.
IIN =
VOUT × I OUT
VIN × η
IIN - Input current;IOUT – Output current;
VOUT – Boost output voltage;
VIN – Input voltage;
η – Efficiency of the boost converter
Then the duty ratio under CCM is shown by the following
equation.
D=
VOUT − VIN + VD
VOUT + VD
VD – Forward conduction drop of output rectifying diode
When the boost converter runs under DCM ( L < Lboundary),
it has the advantages of small inductance and quick transient response; where as if the boost converter works
under CCM (L > Lboundary), normally the converter has higher
efficiency.
When selecting an inductor, another factor to consider is
the peak-to-peak inductor current ripple, which is given
by the following equation:
ΔIL =
VIN × D
fSW × L
Usually this peak-to-peak inductor current ripple can be
chosen between 30% to 50% of the maximum input DC
current. This gives the best compromise between the
inductor size and converter efficiency. The peak inductor
current can be calculated using the following equation:
IL-peak = IIN +
VIN × D
2 × fSW × L
For most applications, an inductor with a value of 2.2µH to
22µH should be acceptable, (refer to the detailed application circuit on page 23, Figure 2). The inductor peak
current must be less than its saturation rating. When the
inductor current is close to the saturation level, its inductance can decrease 20% to 35% from the 0A value depending on the vendor specifications. Using a small value
inductor forces the converter in DCM, in which case the
inductor current ramps down to zero before the end of
each switching cycle. It reduces the boost converter’s
maximum output current and produces a larger input
voltage ripple. The DCR of the inductor plays a significant
role for the total system efficiency and usually there is a
trade-off between the DCR and size of the inductor. Table
4 lists some recommended inductors and their vendors.
Table 4. Recommended Inductors
Inductor
Vendor Website
HCM0703, 2.2uH~10uH
www.cooperindustries.com
IHLP-2525CZ-01, 4.7uH~10uH
www.vishay.com
MLPC0730L, 2.2uH~4.7uH
www.nec-tokin.com/english
Output Capacitor Selection
The next design task is targeting the proper amount of
output ripple voltage due to the constant-current LED
loads. Usually X5R or X7R ceramic capacitor is recommended. The ceramic capacitor minimum capacitance
needed for a given ripple can be estimated using the following equation:
C OUT =
(VOUT − VIN )× IOUT
VOUT ×f SW ×VRIPPLE
20
SC5014
Application Information (continued)
VRIPPLE – Peak to peak output ripple.
The ripple voltage should be less than 200mV (pk-pk) to
ensure good LED current sink regulation. For example, a
typical application where 120mA/channel current is
needed, the total output current for 4 channels will be
480mA, and 6x 4.7µF capacitors are recommended.
During load transient, the output capacitor supplies or
absorbs additional current before the inductor current
reaches its steady state value. Larger capacitance helps
with the overshoot/undershoot during load transient and
loop stability.
Input Capacitor Selection
X5R or X7R ceramic capacitor is recommended for input
bypass capacitor. A 1µF capacitor is sufficient for the VCC
input. Bypass the VIN input with a 10µF or larger ceramic
capacitor.
Output Freewheeling Diode Selection
Schottky diodes are the ideal choice for the SC5014 due to
their low forward voltage drop and fast switching speed.
Table 5 shows several different Schottky diodes that work
properly with the SC5014. Verify that the diode has a
voltage rating greater than the maximum possible output
voltage. The diode conducts current only when the power
switch is turned off. The diode must be rated to handle the
average output current. A diode rated for 1A average
current will be sufficient for most designs.
voltage. The external power MOSFET should be selected
with its voltage rating higher than the output voltage by
minimum 30%. The current rating should be enough to
handle the inductor peak current. Low RDS(on) MOSFETs
are preferred for achieving better efficiency.
The GD (gate driver) on SC5014 provides 1A (peak) current
driving capability which is suitable for most MOSFETs for
high frequency operation. The average current required to
drive the MOSFET is given by the following equation.
IGATE = QG x fSW
QG — Gate charge
The RDS(ON) and its RMS current IS_RMS of the power MOSFET
will generate the conduction loss using the following
equation.
PCOND = IS_RMS2 x RDS(on)
The MOSFET’s switch loss can be calculated using the following equation.
PSW = ½ x VIN x IL_PEAK x fSW x (TON + TOFF)
Where TON and TOFF are the MOSFET’s on and off time
and they can be estimated by the following
equations.
TON = t r +
(5 − V
Q gd
plateau
)/ (5 + R )
g
Table 5. Recommended Rectifier Diodes
Rectifier Diode
DFLS140
SS14/15/16, SS24/25/26
Vendor Website
www.diodes.com
www.vishay.com
External Power MOSFET Selection
The boost converter in SC5014 uses an external power
MOSFET to regulate the output voltage and output power
to drive LED loads. This boost switching structure has an
advantage in that the SC5014 is not exposed to high
voltage. Only the external power MOSFET, freewheeling
diode and the inductor will be exposed to the output
TOFF = t f +
Q gd
Vplateau / (5 + R g )
Where tr, tf, Qgd and Vplateau can usually be found from datasheet of the selected MOSFET. Rg is the resistance of the
optional resistor connected in series on the gate of the
MOSFET.
21
SC5014
Components Selection (continued)
Current Sensing Resistor Selection
The switch current is sensed via the current sensing resistor, RCS. The sensed voltage at this pin is used to set the
peak switch current limit and also used for steady state
regulation of the inductor current. The current limit comparator has a trip voltage of 0.4V (typical). R CS value is
chosen to set the peak inductor and switch current using
the following equation.
I2SW(Peak) = 0.4/RCS
The power dissipation in RSNS can be calculated using the
following equations.
PR_CS = IRMS2 x RCS
IRMS = D x [IO/(1-D)]2
IO = Output DC Current, D = Duty Cycle
For the typical application circuit shown in the detailed
application circuit (page 23, Figure 2), the power dissipation on the sensing resistor is shown by the following
equations.
Assuming VIN = 6V and VOUT = 31.5V, thus D = 81%,
PR_CS = 0.81 X (0.48/0.19)2 X 0.08 = 0.414(W)
For this example, a 0.08 Ω 1% thick-film chip resistor rated
at 1W can be used.
PLL Filter Component Selection
The detailed application circuit on page 23, Figure 2 shows
the optimal R/C filter components for the PLL compensation. These are optimized for internal 1MHz switching frequency. Please contact Semtech Power management
Application Group if a different switching frequency is
selected.
22
SC5014
C1
R2
Q1
24.3kΩ
357kΩ
R12 10 WLEDs per channel
10kΩ
80mΩ
R1
10kΩ
R3
VCC
10kΩ
IO2
EN
20kΩ
OVP
IO1
UVLO
R15
FLT
IO3
SC5014
SCL
SCL
SDA
SDA
PWM
PWM
IO4
REF
SCP
PAD
CPLL
2.2µF
FLT
4.7µF/50V
x6PCS
R9
C12
CS
GND
C6
AON7244
NDRV
VCC (5V)
R11
R5,40.2kΩ
R4
10kΩ
FSET
10µF/35V
x2PCS
Vout
B260
PGND
PGND
D1
L1
4.7µH
ISET
VIN
(6-27V)
R7,110kΩ
C3
C4
C5
1µF
100pF
2.7pF
R8
R6
25.5kΩ 100kΩ
Figure 2— Application Circuit Example, 40 LED @ 100mA
C1
R2
Q1
13kΩ
PGND
R3
VCC
10kΩ
IO2
EN
20kΩ
FLT
SCL
SCL
SDA
SDA
PWM
PWM
SCP
OVP
IO1
UVLO
R15
FLT
10kΩ
100mΩ
R1
10kΩ
CS
2.2µF/10V
249kΩ
R12 5 WLEDs per channel
RCS
C12
NDRV
GND
C6
Si2318
IO3
S C 504
IO4
PAD
REF
VCC (5V)
R11
FSET
10µF/6.3V
x2PCS
Vout
B140
ISET
PGND
D1
L1
NC
VIN
(3-4.2V)
R5,60.4kΩ
R4
10kΩ
C3
1µF
R8
R6
127kΩ 100kΩ
Figure 3— Li-Ion Powered Display Application Circuit Example, 20 LED @ 20mA
23
SC5014
C8
L1
D1
R11
PGND
R2
C6
R12
RCS
C12
R1
OVP
VCC
IO1
UVLO
R15
IO2
EN
FLT
SCL
SCL
SDA
SDA
PWM
PWM
IO3
S C 504
IO4
PAD
REF
SCP
R5
ISET
20kΩ
FLT
PGND
R3
10kΩ
CPLL
2.2µF
CS
GND
L2
Q1
NDRV
VCC (5V)
Vout
C1
FSET
VIN
(6-27V)
R7,110kΩ
R4
R6
R8
C3
C4
C5
1µF
100pF
2.7pF
Figure 4— SEPIC Configuration
C1
R2
Q1
75kΩ
R3
R12 20 WLEDs per channel
10kΩ
VCC
10kΩ
IO2
EN
FLT
SCL
SCL
SDA
SDA
PWM
PWM
SCP
IO4
PAD
R5,40.2kΩ
R4
10kΩ
IO3
S C 504
CPLL
20kΩ
OVP
IO1
UVLO
R15
FLT
787kΩ
50mΩ
R1
10kΩ
CS
2.2µF
2.2µF/100V
x6PCS
RCS
C12
REF
GND
C6
AON6482
NDRV
VCC (5V)
R11
FSET
10µF/25V
x3PCS
Vout up to 70V
DFLS1100
PGND
PGND
D1
L1
3.3µH
ISET
VIN
(12-19V)
VIN
R7,110kΩ
C3
C4
C5
1µF
100pF
2.7pF
R8
R6
25.5kΩ 250kΩ
Figure 5— Cascode Configuration drives 80 LEDs@100mA
24
SC5014
Serial Interface
acknowledges and the master terminates the transfer with
the stop condition [P].
The I2C General Specification
The SC5014 is a read-write slave-mode I C device and
complies with the NXP B.V. I2C standard Version 2.1, dated
January 2000. The SC5014 has 11 user-accessible internal
8-bit registers. The I2C interface has been designed for
program flexibility, supporting direct format for write
operation. Read operations are supported on both combined format and stop separated format. While there is no
auto increment/decrement capability in the SC5014 I2C
logic, a tight software loop can be designed to randomly
access the next register independent of which register
you begin accessing. The start and stop commands frame
the data-packet and the repeat start condition is allowed
if necessary.
2
Limitations to the I2C Specifications
The SC5014 only recognizes 7-bit addressing. This means
that 10-bit addressing and CBUS communication are not
compatible. The device can operate in either standard
mode (100kbit/s) or fast mode (400kbit/s).
Slave Address Assignment
The 7-bit slave address is 0101 111x. The eighth bit is the
data direction bit. 0x5F is used for read operation and
0x5E is used for write operation.
(2) Combined Format — Read
After the start condition [S], the slave address is sent, followed by an eighth bit indicating a write. The SC5014 I2C
then acknowledges that it is being addressed, and the
master responds with an 8-bit data byte consisting of the
register address. The slave acknowledges and the master
sends the repeated start condition [Sr]. Once again, the
slave address is sent, followed by an eighth bit indicating
a read. The slave responds with an acknowledge and the
8-bit data from the previously addressed register; the
master then sends a non-acknowledge (NACK). Finally, the
master terminates the transfer with the stop condition [P].
(3) Stop Separated Reads
Stop-separated reads can also be used. This format allows
a master to set up the register address pointer for a read
and return to that slave at a later time to read the data. In
this format the slave address followed by a write command
are sent after a start [S] condition. The SC5014 then
acknowledges it is being addressed, and the master
responds with the 8-bit register address. The master sends
a stop or restart condition and may then address another
slave. After performing other tasks, the master can send a
start or restart condition to the SC5014 with a read
command. The device acknowledges this request and
returns the data from the register location that had
previously been set up.
Supported Formats
The supported formats are described in the following
subsections.
(1) Direct Format — Write
The simplest format for an I2C write is direct format. After
the start condition [S], the slave address is sent, followed
by an eighth bit indicating a write. The SC5014 I2C then
acknowledges that it is being addressed, and the master
responds with an 8-bit data byte consisting of the register
address. The slave acknowledges and the master sends
the appropriate 8-bit data byte. Once again, the slave
25
SC5014
I2C Direct Format Write
S
SlaveAddress
W
A
RegisterAddress
S– StartCondition
W–Write=‘0’
A–Acknowledge(sentbyslave)
P–Stopcondition
A
Data
A
P
SlaveAddress– 7-bit
Registeraddress– 8-bit
Data– 8-bit
I2C Stop Separated Format Read
MasterAddresses
otherSlaves
RegisterAddressSetupAccess
S SlaveAddress W A RegisterAddress A P S
S– StartCondition
W–Write=‘0’
R–Read=‘1’
A–Acknowledge(sentbyslave)
NAK–Non-Acknowledge(sentbymaster)
Sr–RepeatedStartcondition
P–Stopcondition
SlaveAddressB
RegisterReadAccess
S/Sr
SlaveAddress
R A
Data
NACK P
SlaveAddress– 7-bit
Registeraddress– 8-bit
Data– 8-bit
I2C Combined Format Read
S
SlaveAddress
W A
RegisterAddress
S– StartCondition
W–Write=‘0’
R–Read=‘1’
A–Acknowledge(sentbyslave)
NAK–Non-Acknowledge(sentbymaster)
Sr–RepeatedStartcondition
P–Stopcondition
A Sr
SlaveAddress
R
A
Data
NACK P
SlaveAddress– 7-bit
Registeraddress– 8-bit
Data– 8-bit
26
SC5014
Register Map
Bit 2
Bit 1
Bit 0
Reset
Value
Description
LED_
OPEN
OTP
OVP
FAULT
0x00
Fault Status
FLT_EN
PHASE_
SHIFT
INT_
DUTY
INT_
PWM
0xB5
Device Control
IDAC2
IDAC1
IDAC0
0x1F
Analog Dimming
Control
D9
D8
0x00
Dimming Duty Cycle
Control 1
Address
Bit 7
Bit 6
Bit 5
Bit 4
0x00
CLF
PLL_RDY
LED_
SHORT
0x01
WND1
WND0
FAST_
FREQ
0x02
IDAC4
Bit 3
IDAC3
0x03
0x04
D7
D6
D5
D4
D3
D2
D1
D0
0x00
Dimming Duty Cycle
Control 2
0x05
FREQ7
FREQ6
FREQ5
FREQ4
FREQ3
FREQ2
FREQ1
FREQ0
0x00
Dimming Frequency
Select
NPLL17
NPLL16
0x00
PLL Divider MSB
0x06
0x07
NPLL15
NPLL14
NPLL13
NPLL12
NPLL11
NPLL10
NPLL9
NPLL8
0x00
PLL Divider LSB2
0x08
NPLL7
NPLL6
NPLL5
NPLL4
NPLL3
NPLL2
NPLL1
NPLL0
0x08
PLL Divider LSB1
0x09
FADE_EN
FADE_
TYPE
STEP_
MUL2
STEP_
MUL1
STEP_
MUL0
0x80
Fade Options
FADE_
RATE2
FADE_
RATE1
FADE_
RATE0
0x00
Fade Rate
0x0A
FADE_
RATE6
FADE_
RATE5
FADE_
RATE4
FADE_
RATE3
27
SC5014
Definition of Registers and Bits
Fault Status Register
Bit Field
Definition
Read / Write Description
0x00 [7]
CLF
W
Clear latching flags bit.
(Set = 1 to clear OTP, LED_OPEN, LED_SHORT and mask OVP for 32 to 64μs)
0x00 [6]
PLL_RDY
R
PLL ready status
0x00 [5]
LED_SHORT
R
One or more LED strings faulted shorted
0x00 [4]
LED_OPEN
R
One or more LED strings faulted open
0x00 [2]
OTP
R
Thermal shutdown (1 = thermal OTP fault)
0x00 [1]
OVP
R
Output over-voltage fault ( 1 = OVP )
0x00 [0]
FAULT
R
OR of all fault conditions (0= no fault, 1 = fault condition)
28
SC5014
Definition of Registers and Bits (continued)
Device Control Register
Bit Field
0x01 [7:6]
Definition
WIN[1:0]
Read / Write Description
R/W
A modified duty cycle sent into the PWMI pin replaces the existing saved duty cycle when its
deviation from the saved duty is outside the window for two consecutive samples.
00 = 0 bits (no window)
01 = ±1 bit window
10 = ±2 bit window
11 = ±3 bit window
0x01 [5]
FAST_FREQ
R/W
Determines the LED PWM dimming frequency selection:
1 = High PWM dimming frequency mode assuming 9-bit PWM duty cycle dimming, dividing
the system clock 10MHz / (512 x (FREQ+1)).
0 = Low PWM dimming frequency mode assuming 10-bit PWM duty cycle dimming, dividing
the system clock 10MHz / (1024 x (FREQ+1)).
0x01 [4]
FLT_EN
R/W
This bit enables fault checking:
0 = LED_OPEN and LED_SHORT faults are not checked.
1 = LED_OPEN and LED_SHORT faults are checked.
0x01 [2]
PH_SHIFT
R/W
Enables String-by-String phase shifting. This is a don’t care if INT_PWM=0.
0 = Phase shifting disabled.
1 = Phase shifting is enabled.
0x01 [1]
INT_DUTY
R/W
Determines the duty cycle source. This is a don’t care if INT_PWM = 0.
0 = LED duty cycle is set by the PWMI input.
1 = LED duty cycle is set by the 10-bit duty cycle control registers.
R/W
Sets the LED PWM dimming source.
0 = LED PWM dimming driven directly from the PWMI input source (direct PWM dimming).
1 = LED PWM dimming driven from an internal oscillator (required for phase-shifted PWM
dimming); enables the PLL.
0x01 [0]
INT_PWM
Analog Dimming Control Register
Bit Field
Definition
0x02 [4:0]
IDAC [4:0]
Read / Write Description
R/W
5-bit analog dimming register — The LED current can adjusted in 32 steps from 0mA to max
value determined by RISET.
29
SC5014
Definition of Registers and Bits (continued)
Dimming Duty Cycle Control Register
Bit Field
Definition
0x03 [1:0]
0x04 [7:0]
D [9:0]
Read / Write Description
R/W
10-bit PWM brightness setting — This value is spread over registers: 0x03 (MSB) and 0x04
(LSB).
Dimming Frequency Select Register
Bit Field
Definition
0x05 [7:0]
FREQ [7:0]
Read / Write Description
R/W
This register sets the LED dimming frequency.
FAST_FREQ = 1, then LED dimming frequency is equal to 10MHz / (512 x (FREQ+1)).
FAST_FREQ = 0, then LED dimming frequency is equal to 10MHz / (1024 x (FREQ+1)).
PLL Control Registers
Bit Field
Definition
0x06 [1:0]
0x07 [7:0]
0x08 [7:0]
NPLL [17:0]
Read / Write Description
R/W
These registers set the PLL divider value — The system clock is intended to run at 10MHz; this
value divides the system clock down to a frequency comparable to the SYNC signal’s frequency to allow PLL synchronization. Typical values are shown below.
FIN
PLL Divider N
Register Values
FPLL = (N+2) × FIN
60 Hz
169,982
0x02 - 0x97 - 0xFE
10MHz
1 MHz
8
0x00 - 0x00 - 0x08
10MHz
Fade Options Registers
Bit Field
Definition
Read / Write Description
0x09 [7]
FADE_EN
R/W
Enables the fading feature.
FADE_EN = 0: No Fading; Jumps directly to new PWM value.
FADE_EN = 1: Enables fading.
0x09 [6]
FADE_TYPE
R/W
Selects the fading type.
FADE_TYPE = 0: Logarithmic Fading.
FADE_TYPE = 1: Linear Fading.
30
SC5014
Definition of Registers and Bits (continued)
Bit Field
0x09 [2:0]
Definition
STEP_MUL
[2:0]
Read / Write Description
Used to speed up fade time, when selected LED PWM dimming frequency is low. Define a 2N
multiplier of the fade amount.
STEP_MUL[2:0] = 000, N=0, multiplier = 1
STEP_MUL[2:0] = 001, N=1, multiplier = 21 = 2
STEP_MUL[2:0] = 010, N=2, multiplier = 22 = 4
STEP_MUL[2:0] = 011, N=3, multiplier = 23 = 8
STEP_MUL[2:0] = 100, N=4, multiplier = 24 = 16
STEP_MUL[2:0] = 101~111, N=5, multiplier = 25 = 32
R/W
Fade Rate Register
Bit Field
Definition
0x0A [6:0]
FADE_RATE
[6:0]
Read / Write Description
R/W
Defines how often the duty is changed during a fade.
Fade rate = PWM Output Rate / (1 + FADE_RATE[6:0])
31
SC5014
Outline Drawing — MLPQ-20 4x4
A
B
D
PIN1
INDICATOR
(LASERMARK)
DIMENSIONS
INCHES
MILLIMETERS
DIM
MIN NOM MAX MIN NOM MAX
A
A1
A2
b
D
D1
E
E1
e
L
N
aaa
bbb
E
A2
A
.031 .035 .039
.000 .001 .002
- (.008) .007 .010 .012
.154 .157 .161
.100 .106 .110
.154 .157 .161
.100 .106 .110
.020BSC
.012 .016 .020
20
.004
.004
0.80 0.90 1.00
0.00 0.02 0.05
- (0.20) 0.18 0.25 0.30
3.90 4.00 4.10
2.55 2.70 2.80
3.90 4.00 4.10
2.55 2.70 2.80
0.50BSC
0.30 0.40 0.50
20
0.10
0.10
SEATING
PLANE
aaa C
A1
C
D1
LxN
E/2
E1
2
1
N
bxN
e
bbb
C A B
D/2
NOTES:
1. CONTROLLINGDIMENSIONSAREINMILLIMETERS(ANGLESINDEGREES).
2. COPLANARITYAPPLIESTOTHEEXPOSEDPADASWELLASTHETERMINALS.
32
SC5014
Land Pattern — MLPQ-20 4x4
K
DIMENSIONS
(C)
G
H
Y
Z
DIM
C
G
H
K
P
X
Y
Z
INCHES
(.156)
.122
.106
.106
.020
.010
.033
.189
MILLIMETERS
(3.95)
3.10
2.70
2.70
0.50
0.25
0.85
4.80
X
P
NOTES:
1. THISLANDPATTERNISFORREFERENCEPURPOSESONLY.
CONSULTYOURMANUFACTURINGGROUPTOENSUREYOUR
COMPANY'SMANUFACTURINGGUIDELINESAREMET.
2. THERMALVIASINTHELANDPATTERNOFTHEEXPOSEDPAD
SHALLBECONNECTEDTOASYSTEMGROUNDPLANE.
FAILURETODOSOMAYCOMPROMISETHETHERMALAND/OR
FUNCTIONALPERFORMANCEOFTHEDEVICE.
33
SC5014
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34