LP3954 Advanced Lighting Management Unit
Literature Number: SNVS340C
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954 Advanced Lighting Management UnitLP3954
Advanced Lighting Management Unit
General Description
LP3954 is an advanced lighting management unit for hand-held devices. It drives any phone lights including displaybacklights, RGB, keypad and camera flash LEDs. The boostDC-DC converter drives high current loads with high efficien-cy. White LED backlight drivers are high efficiency low voltagestructures with excellent matching and automatic fade in/ fadeout function. The new stand-alone command based RGBcontroller is feature rich and easy to configure. Built-in audiosynchronization feature allows user to synchronize the colorLEDs to audio input. Integrated high current driver can drivecamera flash LED or motor/vibra. Internal ADC can be usedfor ambient light or temperature sensing. The flexible SPI/I2Cinterface allows easy control of LP3954. Small micro SMDpackage together with minimum number of external compo-nents is a best fit for handheld devices.
Features
■■■■■■■■■■
Audio synchronization for color/RGB LEDs
Command based PWM controlled RGB LED driversHigh current driver for flash LED with built-in timing.4+2 or 6 low voltage constant current white LED driverswith programmable 8-bit adjustment (0…25mA/LED)High efficiency Boost DC-DC converterSPI / I2C compatible interface
Possibility for external PWM dimming control
Possibility for clock synchronization for RGB timingAmbient light and temperature sensing possibility
Small package – micro SMD or micro SMDxt, 3.0 x 3.0 x0.6mm
Applications
■Cellular Phones■PDAs, MP3 players
Typical Applications
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LCONNECTION DIAGRAMS
Micro SMD Package, 3.0 x 3.0 x 0.6mm, 0.5mm pitch NS Package Number TLA36AAA orMicro SMDxt Package, 3.0 x 3.0 x 0.65mm, 0.5mm pitch NS Package Number RLA36AAA
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PACKAGE MARK
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ORDERING INFORMATION
Order NumberLP3954TLLP3954TLXLP3954RLLP3954RLX
Package Marking
D49BD49BD49BD49B
Supplied AsTNR 250TNR 1000TNR 250TNR 1000
Spec/FlowNoPBNoPBNoPBNoPB
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54Pin #6F6E6D6C6B6A5F5E5D5C5B5A4F4E4D4C4B4A3F3E3D3C3B3A2F2E2D2C2B2A1F1E1D1C1B1A
NameSWFBFLASHR1G1B1GND_SWGNDVDDIOSS/SDAIRGBGND_RGBGND_WLEDIFLASHSYNC_PWM
SISOR2WLED5WLED6VDD1EN_FLASHSCK/SCLG2WLED3WLED4ASEIRTIF_SELB2WLED1WLED2GNDAVREFVDDAVDD2
TypeOutputInputOutputOutputOutputOutputGroundGroundPowerLogic Input/Output
InputGroundGroundInputLogic InputLogic InputLogic OutputOutputOutputOutputPowerLogic InputLogic InputOutputOutputOutputInputInputLogic InputOutputOutputOutputGroundOutputPowerPower
Boost Converter Power SwitchBoost Converter FeedbackHigh Current Flash OutputRed LED 1 OutputGreen LED 1 OutputBlue LED 1 OutputPower Switch GroundGround
Description
Supply Voltage for Input/output Buffers and DriversSlave Select (SPI), Serial Data In/Out (I2C)Bias Current Set Resistor for RGB DriversGround for RGB CurrentsGround for WLED Currents
High Current Flash Current Set Resistor
External PWM Control for LEDs or External Clock for RGB SyncSerial Input (SPI), Address Select (I2C)Serial Data Out (SPI)Red LED 2 outputWhite LED 5 outputWhite LED 6 outputSupply voltage
Enable for High Current FlashClock (SPI/I2C)Green LED 2 OutputWhite LED 3 outputWhite LED 4 outputAudio Synchronization InputOscillator Frequency Resistor
Interface (SPI or I2C compatible) Selection (IF_SEL = 1 for SPI)Blue LED 2 OutputWhite LED 1 OutputWhite LED 2 OutputGround for Analog CircuitryReference VoltageInternal LDO OutputSupply Voltage
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If Military/Aerospace specified devices are required,please contact the National Semiconductor Sales Office/Distributors for availability and specifications.V (SW, FB, R1-2, G1-2, B1-2,FLASH, WLED1-6)(Notes 3, 4)VDD1, VDD2, VDD_IO, VDDA
Voltage on ASE, IRT, IFLASH,IRGB, VREF
Voltage on Logic Pins
V(all other pins): Voltage to GNDI (VREF)
I(R1, G1, B1, R2, G2, B2)I(FLASH)(Note 5)
Continuous Power Dissipation(Note 6)
Junction Temperature (TJ-MAX)Storage Temperature RangeMaximum Lead Temperature(Soldering) (Note 7)ESD Rating (Note 8)Human Body Model:
-0.3V to +7.2V
-0.3V to +6.0V-0.3V to VDD1+0.3V
with 6.0V max
-0.3V to VDD_IO +0.3V
with 6.0V max-0.3V to 6.0V
10µA100mA400mA
Internally Limited
150°C
-65°C to +150°C
260ºC
2kV
V (SW, FB, WLED1-6, R1-2, G1-2,B1-2, FLASH)
VDD1,2 with external LDOVDD1,2 with internal LDOVDDAVDD_IO
Voltage on ASE
Recommended Load CurrentJunction Temperature (TJ) RangeAmbient Temperature (TA) Range(Note 9)
L0 to 6.0V
2.7 to 5.5V3.0 to 5.5V2.7 to 2.9V1.65V to VDD
0.1V to VDDA –0.1V
0mA to 300mA-30°C to +125°C-30°C to +85°C
Thermal Properties
Junction-to-Ambient ThermalResistance(θJA), TLA36AAA orRLA36AAA Package(Note 10)
60°C/W
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(Notes 2, 11)
Limits in standard typeface are for TJ = 25° C. Limits in boldface type apply over the operating ambient temperature range (-30°C < TA < +85°C). Unless otherwise noted, specifications apply to the LP3954 Block Diagram with: VDD1 = VDD2 = 3.6V, VDDIO =2.8V, CVDD = CVDDIO = 100nF, COUT = CIN = 10µF, CVDDA = 1µF, CREF = 100nF, L1 = 4.7µH, RFLASH =1.2k, RRGB =5.6k and RRT=82k (Note 12).SymbolIVDD
Parameter
Standby supply current(VDD1, VDD2)
No-boost supply current(VDD1, VDD2)
Condition
NSTBY = LSCK, SS, SI
NSTBY = H,EN_BOOST = LSCK, SS, SI
Audio sync and LEDs OFFNSTBY = H,EN_BOOST = HSCK, SS, SI
Audio sync and LEDs OFFAutoload OFF
CC mode at R1, G1, B1 andR2, G2, B2 set to 15mASW mode
4+2 banks IOUT/LED 25mAAudio sync ONVDD1,2 = 2.8VVDD1,2 = 3.6V
Flash
(VDD1, VDD2)
IVDDIO
VDDIO Standby Supplycurrent
VDDIO supply current
IEXT_LDOVDDA
External LDO output current(VDD1, VDD2, VDDA)Output voltage of internalLDO for analog parts
I(RFLASH)=1mA
Peak current during flashNSTBY = L
SCK, SS, SI = H
1MHz SCK frequency in SPImode, CL = 50pF at SO pin7V tolerant application onlyIBOOST = 300mA(Note 13)
Min
Typ1
Max8400
UnitsµAµA
Electrical Characteristics
54No-load supply current(VDD1, VDD2)
1mA
RGB drivers(VDD1, VDD2)WLED drivers(VDD1, VDD2)
Audio synchronization(VDD1, VDD2)
2.72-3
150150500 3907002 20 2.80
1 6.52.88+3
µA
µA
µAmAµAµAmAV%
Note 1:Absolute Maximum Ratings indicate limits beyond which damage to the component may occur. Operating Ratings are conditions under which operationof the device is guaranteed. Operating Ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions,see the Electrical Characteristics tables.
Note 2:All voltages are with respect to the potential at the GND pins.
Note 3:Battery/Charger voltage should be above 6V no more than 10% of the operational lifetime.
Note 4:Voltage tolerance of LP3954 above 6.0V relies on fact that VDD1 and VDD2 (2.8V) are available (ON) at all conditions. If VDD1 and VDD2 are not available(ON) at all conditions, National Semiconductor does not guarantee any parameters or reliability for this device.
Note 5:The total load current of the boost converter in worst-case conditions should be limited to 300mA (min. input and max. output voltage).
Note 6:Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at TJ=160°C (typ.) and disengages atTJ=140°C (typ.).
Note 7:For detailed soldering specifications and information, please refer to National Semiconductor Application Note AN1112 : Micro SMD Wafer Level ChipScale Package or Application Note AN1412 : Micro SMDxt Wafer Level Chip Scale Package.
Note 8: The Human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. The machine model is a 200pF capacitor dischargeddirectly into each pin. MIL-STD-883 3015.7
Note 9:In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may have to bederated. Maximum ambient temperature (TA-MAX) is dependent on the maximum operating junction temperature (TJ-MAX-OP = 125°C), the maximum power
dissipation of the device in the application (PD-MAX), and the junction-to ambient thermal resistance of the part/package in the application (θJA), as given by thefollowing equation: TA-MAX = TJ-MAX-OP – (θJA × PD-MAX).
Note 10:Junction-to-ambient thermal resistance is highly application and board-layout dependent. In applications where high maximum power dissipation exists,special care must be paid to thermal dissipation issues in board design.
Note 11:Min and Max limits are guaranteed by design, test, or statistical analysis. Typical numbers are not guaranteed, but do represent the most likely norm.Note 12:Low-ESR Surface-Mount Ceramic Capacitors (MLCCs) used in setting electrical characteristics.Note 13:VDDA output is not recommended for external use.
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54In the RESET mode all the internal registers are reset to the default values and the chip goes to STANDBYmode after reset. NSTBY control bit is low after reset by default. Reset is entered always if Reset Registeris written or internal Power On Reset is active. There is no dedicated Reset pin available. LP3954 can bereset by writing any data to Reset Register in address 60H. Power On Reset (POR) will activate during thechip startup or when the supply voltage VDD2 falls below 1.5V. Once VDD2 rises above 1.5V, POR willinactivate and the chip will continue to the STANDBY mode.
STANDBY:The STANDBY mode is entered if the register bit NSTBY is LOW. This is the low power consumption mode,
when all circuit functions are disabled. Registers can be written in this mode and the control bits are effectiveimmediately after power up.
STARTUP:When NSTBY bit is written high, the INTERNAL STARTUP SEQUENCE powers up all the needed internal
blocks (Vref, Bias, Oscillator etc..). To ensure the correct oscillator initialization, a 10ms delay is generatedby the internal state-machine. If the chip temperature rises too high, the Thermal Shutdown (THSD) disablesthe chip operation and STARTUP mode is entered until no thermal shutdown event is present.
BOOST STARTUP:Soft start for boost output is generated in the BOOST STARTUP mode. The boost output is raised in PFM
mode during the 10ms delay generated by the state-machine. The Boost startup is entered from InternalStartup Sequence if EN_BOOST is HIGH or from Normal mode when EN_BOOST is written HIGH. Duringthe 10ms Boost Startup time all LED outputs are switched off to ensure smooth start-up.
NORMAL:During NORMAL mode the user controls the chip using the Control Registers. The registers can be written
in any sequence and any number of bits can be altered in a register in one write
RESET:
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The LP3954 Boost DC/DC Converter generates a 4.0 – 5.3Vvoltage for the LEDs from single Li-Ion battery (3V…4.5V).The output voltage is controlled with an 8-bit register in 9steps. The converter is a magnetic switching PWM mode DC/DC converter with a current limit. The converter has three op-tions for switching frequency, 1MHz, 1.67MHz and 2MHz(default), when timing resistor RT is 82kohm. Timing resistordefines the internal oscillator frequency and thus directly af-fects boost frequency and all circuit's internally generatedtiming (RGB, Flash, WLED fading).
The LP3954 Boost Converter uses pulse-skipping eliminationto stabilize the noise spectrum. Even with light load or no loada minimum length current pulse is fed to the inductor. An ac-tive load is used to remove the excess charge from the outputcapacitor at very light loads. At very light load and when inputand output voltages are very close to each other, the pulseskipping is not completely eliminated. Output voltage shouldbe at least 0.5V higher than input voltage to avoid pulse skip-ping. Reducing the switching frequency will also reduce therequired voltage difference.
Active load can be disabled with the en_autoload bit. Dis-abling will increase the efficiency at light loads, but the down-side is that pulse skipping will occur. The Boost Convertershould be stopped when there is no load to minimise the cur-rent consumption.
rent is measured and controlled with the feedback. The uscan program the output voltage of the boost converter. Toutput voltage control changes the resistor divider in the feeback loop.
The following figure shows the boost topology with the prtection circuitry. Four different protection schemes are impmented:1.
Over voltage protection, limits the maximum outputvoltage
L2.
—Keeps the output below breakdown voltage.
—Prevents boost operation if battery voltage is muchhigher than desired output.
Over current protection, limits the maximum inductorcurrent
3.4.
—Voltage over switching NMOS is monitored; too hivoltages turn the switch off.
Feedback break protection. Prevents uncontrolledoperation if FB pin gets disconnected.
Duty cycle limiting, done with digital control.
Boost Converter Topology
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54SymbolILOAD
Parameter
Load Current
3.0V ≤ VINVOUT = 5V3.0V ≤ VINVOUT = 4V
ConditionsMin00−5 −6−9
700550
Typ
VIN–V(SCHOTTKY)
0.42±32510800
Max300
Units
mA
400+5 0.8 +6+9
%VΩMHz%ns
900950
msmA
VOUT
Output Voltage Accuracy(FB Pin)Output Voltage(FB Pin)
3.0V ≤ VIN ≤ VOUT - 0.5VOUT = 5.0V
1 mA ≤ ILOAD ≤ 300 mAVIN > 5V + V(SCHOTTKY)VDD1,2 = 2.8V, ISW = 0.5ART = 82 kΩ
freq_sel[2:0] = 1XX2.7 ≤ VDDA ≤ 2.9RT = 82 kΩno load
Boost startup from STANDBY
RDSONfPWF
Switch ON ResistancePWM Mode SwitchingFrequency
Frequency Accuracy
tPULSEtSTARTUPISW_MAX
Switch Pulse MinimumWidthStartup TimeSW Pin Current Limit
BOOST STANDBY MODE
User can stop the Boost Converter operation by writing theEnables register bit EN_BOOST low. When EN_BOOST iswritten high, the converter starts for 10ms in PFM mode andthen goes to PWM mode.
BOOST OUTPUT VOLTAGE CONTROL
User can control the boost output voltage by boost output 8-bit register.
Boost Output [7:0]Register 0DHBin0000 00000000 00010000 00110000 01110000 11110001 11110011 11110111 11111111 1111
Hex000103070F1F3F7FFF
4.004.254.404.554.704.855.00 Default
5.155.30Boost OutputVoltage (typical)
Boost Output Voltage Control
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BOOST FREQUENCY CONTROL
freq_sel[2:0]
1XX01X001
frequency2.00 MHz1.67 MHz1.00 MHz
Register ‘boost freq’ (address 0EH). Register default valueafter reset is 07H.
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分销商库存信息:
NATIONAL-SEMICONDUCTORLP3954RL/NOPBLP3954RLX/NOPBLP3954TL/NOPB
LP3954TLX/NOPB
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