4-Channel Quad-Mode) LEDDriver with Open/Short LEDDetection
Description
The CAT3604V is a high efficiency Quad−Mode® fractional chargepump that can drive up to four LEDs with input supply voltages as lowas 2.5V.
An external RSET resistor is used to control the LED channelbrightness while channel diagnostics include automatic detection forboth short and open LED channel conditions, ensuring the CAT3604Vmaintains the highest efficiency level in all operating modes.
Each operating mode uses a constant high frequency switchingscheme which allows the use of small form factor external ceramiccapacitors while delivering excellent low noise input supply ripple upto 5.5 volts.
The EN input control supports direct PWM dimming and canaccommodate dimming frequencies in excess of 10kHz therebyproviding extremely high resolution brightness levels.
The device is available in the 16−pad low profile 0.8mm thin QFN(4mm x 4mm).
Features
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TQFN−16HV4 SUFFIXCASE 510AE
PIN CONNECTIONS
LED1LED2LED3LED4ENNCNCNC
1
GND
GND
C2+C2−C1−
•••••••••••
Quad−mode Charge Pump: 1x, 1.33x, 1.5x, 2xDrives up to 4 LEDs at 30 mA Each
Pin Compatible with Industry Standard ’604Open/Short LED Automatic DetectionPower Efficiency up to 92%High Resolution PWM Dimming
Low Noise Supply Ripple in All ModesSoft Start and Current Limiting
Short Circuit and Thermal Overload Protection16−Pad TQFN Package, 4 mm x 4 mm
These Devices are Pb−Free, Halogen Free/BFR Free and are RoHSCompliant
LCD Display BacklightCellular Phones
Digital Still CamerasHandheld Devices
RSET(4 x 4 mm) (Top View)
MARKING DIAGRAMS
CDAKAXXXYMCC
CDAFAXXXYMCC
Applications
CDAK = CAT3604VHV4−GT2CDAF = CAT3604VHV4−T2A = Assembly Location
XXX = Last Three Digits of Assembly Lot NumberY = Production Year (Last Digit)
M = Production Month (1−9, A, B, C)CC = Country of Origin (Two Digit)Note: Two digit code for country of origin:Thailand = THMalaysia = MY
••••
ORDERING INFORMATION
DeviceCAT3604VHV4−GT2(Note 1)
CAT3604VHV4−T2
PackageTQFN−16(Pb−Free)TQFN−16(Pb−Free)
Shipping2,000/Tape & Reel
1.NiPdAu Plated Finish (RoHS−compliant).For other finishes, please contact factory.
© Semiconductor Components Industries, LLC, 2010
April, 2010 − Rev. 3
1
VOUTPublication Order Number:
CAT3604V/D
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C1+VINCAT3604V
1 mF1 mF2.4 Vto5.5 VVINCIN1 mFC1+C1−C2+C2−VINVOUTCAT3604VENRSETLED1LED2LED3LED4VOUTCOUT1 mF
ONOFF20 mA4.02 kΩGNDFigure 1. Typical Application Circuit
Table 1. ABSOLUTE MAXIMUM RATINGS
Parameter
VIN, LEDx, C1±, C2± voltageVOUT voltageEN voltage
Storage Temperature RangeJunction Temperature RangeLead Temperature
Rating676−65 to +160−40 to +150
300
UnitVVV°C°C°C
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above theRecommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affectdevice reliability.
Table 2. RECOMMENDED OPERATING CONDITIONS
Parameter
VIN
Ambient Temperature RangeILED per LED pinTotal Output CurrentLED Forward Voltage RangeNOTE:
Typical application circuit with external components is shown above.
Rating2.5 to 5.5−40 to +850 to 250 to 1001.3 to 4.3
UnitV_CmAmAV
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CAT3604V
Table 3. ELECTRICAL OPERATING CHARACTERISTICS
(over recommended operating conditions unless specified otherwise) VIN = 3.6 V, EN = High, TAMB = 25°C.SymbolIQ
Quiescent Current
Name
Conditions
1x mode, no load1.33x mode, no load1.5x mode, no load2x mode, no loadVEN = 0 V
ILEDAVG / ILEDAVG−NOMINAL(ILED − ILEDAVG) / ILEDAVGRSET = 34.0 kWRSET = 5.23 kWRSET = 2.67 kW
0.58
1x mode
1.33x mode, VIN = 3 V1.5x mode, VIN = 2.7 V2x mode, VIN = 2.4 V1.33x and 2x mode1.5x modeVOUT < 0.5 VVOUT > 1 V
0.81
±2±1.52.415300.60.8551011.350250130400100
1.3
0.4
15020
1.6
1.8
2.01.31.60.62
Min
Typ1.01.72.22.4
1Max
UnitsmA
IQSHDNILED−ACCILED−DEVILED
Shutdown CurrentLED Current AccuracyLED Channel MatchingProgrammed LED Current
mA%%mA
VRSETROUT
RSET Regulated VoltageOutput Resistance (open loop)
VW
FOSCISC_MAXIIN_MAXLEDTHVHYSRENVHIVLOTSDTHYSVUVLO
Charge Pump FrequencyOutput short circuit Current LimitInput Current Limit
1x to 1.33x, 1.33x to 1.5x or 1.5x to 2xTransition Thresholds at any LED pin1x Mode Transition HysteresisEN Pin
− Internal Pull−down Resistor− Logic High Level− Logic Low LevelThermal ShutdownThermal Hysteresis
Undervoltage lockout (UVLO) threshold
MHzmAmAmVmVkWVV°C°CV
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CAT3604V
Table 4. A.C. CHARACTERISTICS
(For 2.5 V ≤ VIN ≤ 5.5 V, over full ambient temperature range −40 to +85°C.)SymbolTLEDTMDTPWRDWNTLED−ONTLED−OFF
Name
LED current settling time from shutdown modeMode transition timeDevice power down delayLED on settling timeLED off settling time
Conditions
1x mode, VIN = 4 V
1.33x mode, VIN = 3.5 V
Min
Typ404005000.91120
1.5Max
Unitsmsmsmsmsns
Figure 2. CAT3604V Timing Characteristics
LED Current Setting
The nominal LED current is set by the external resistorconnected between the RSET pin and ground. Table 5 listsstandard resistor values for several LED current settings.
Table 5. RESISTOR RSET AND LED CURRENT
LED Current (mA)
251015202530
RSET (kW)40.015.87.875.234.023.162.67
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CAT3604V
TYPICAL PERFORMANCE CHARACTERISTICS
(VIN = 3.6 V, IOUT = 80 mA (4 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, TAMB = 25°C unless otherwise specified.)100
VF = 3.3 V90EFFICIENCY (%)8070605040
EFFICIENCY (%)1x1.33x1.5x807060504090
1x1.33x100
VF = 3.3 V2x4.54.03.53.02.52.04.24.03.83.63.43.23.0INPUT VOLTAGE (V)INPUT VOLTAGE (V)
Figure 3. Efficiency vs. Input Voltage
4
QUIESCENT CURRENT (mA)QUIESCENT CURRENT (mA)VF = 3.3 V3
4
Figure 4. Efficiency vs. Li−Ion Voltage
3
2x1.5x2
21.33x1x1
1
LEDs Off05.55.04.54.03.53.02.52.00−40040TEMPERATURE (°C)
80120INPUT VOLTAGE (V)
Figure 5. Quiescent Current vs. Input Voltage
10LED CURRENT VARIATION (%)6420−2−4−6−8−10LED CURRENT VARIATION (%)8
VF = 3.3 V1086420−2−4−6
Figure 6. Quiescent Current vs. Temperature
VF = 3.3 V2.02.53.03.54.04.55.05.5−8−10−40040TEMPERATURE (°C)
80120INPUT VOLTAGE (V)
Figure 7. LED Current Change vs. Input
VoltageFigure 8. LED Current Change vs.
Temperature
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CAT3604V
TYPICAL PERFORMANCE CHARACTERISTICS
(VIN = 3.6 V, IOUT = 80 mA (4 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, TAMB = 25°C unless otherwise specified.)1.3SWITCHING FREQUENCY (MHz)OUTPUT RESISTANCE (W)1.21.11.0
1.33x, 2x Mode0.90.80.7−401.5x Mode121086420
1.33x1.5x2x1x2.02.53.03.54.04.55.05.5040TEMPERATURE (°C)
80120INPUT VOLTAGE (V)
Figure 9. Switching Frequency vs.
Temperature
4.03.5OUTPUT VOLTAGE (V)3.02.52.01.51.00.500
100
200
300
400
0
1x Mode
LED CURRENT (mA)3040
Figure 10. Output Resistance vs. Input Voltage
20
10
050100150200250300
OUTPUT CURRENT (mA)LED PIN VOLTAGE (mV)
Figure 11. Foldback Current Limit
100
Figure 12. LED Current vs. LED Pin Voltage
LED CURRENT (mA)10
1
110
RSET RESISTANCE (kW)
100
Figure 13. LED Current vs. RSET Resistance
Figure 14. Line Transient Response
(3.6 V to 4.9 V)
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CAT3604V
TYPICAL PERFORMANCE CHARACTERISTICS
(VIN = 3.6 V, IOUT = 80 mA (4 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, TAMB = 25°C unless otherwise specified.)
Figure 15. Operating Waveforms in 1x Mode
Figure 16. Switching Waveforms
in 1.33x Mode
Figure 17. Switching Waveforms
in 1.5x ModeFigure 18. Switching Waveforms
in 2x Mode
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CAT3604V
TYPICAL PERFORMANCE CHARACTERISTICS
(VIN = 3.6 V, IOUT = 80 mA (4 LEDs at 20 mA), CIN = COUT = C1 = C2 = 1 mF, TAMB = 25°C unless otherwise specified.)
Figure 19. Cold Power Up in 1x ModeFigure 20. Cold Power Up in 1.33x Mode
Figure 21. Cold Power Up in 1.5x ModeFigure 22. Cold Power Up in 2x Mode
Figure 23. Cold Power Up (1x Mode)Figure 24. Power Down (1x Mode)
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CAT3604V
Table 6. PIN DESCRIPTION
Pin #12345678910111213141516TAB
NameENNCNCNCRSETVOUTVINC1+C1−C2−C2+GNDLED4LED3LED2LED1GND
Device enable (active high).Not connected inside the package.Not connected inside the package.Not connected inside the package.
Connect resistor RSET to set the LED current.Charge pump output connected to the LED anodes.Charge pump input, connect to battery or supply.Bucket capacitor 1 Positive terminalBucket capacitor 1 Negative terminalBucket capacitor 2 Negative terminalBucket capacitor 2 Positive terminalGround ReferenceLED4 cathode terminal.LED3 cathode terminal.LED2 cathode terminal.LED1 cathode terminal.Connect to GND on the PCB.
Function
Pin Function
VIN is the supply pin for the charge pump. A small 1mFceramic bypass capacitor is required between the VIN pinand ground near the device. The operating input voltagerange is from 2.5 V to 5.5 V. Whenever the input supply fallsbelow the under−voltage threshold (1.8 V), all the LEDchannels are disabled and the device enters shutdown mode.EN is the enable input and the high resolution PWMdimming control. Levels of logic high and logic low are setat 1.3 V and 0.4 V respectively. When EN is initially takenhigh, the device becomes enabled and all LED currents areset according to the RSET resistor. To place the device into“zero current” shutdown mode, the EN pin must be held lowfor at least 1.5 ms.
VOUT is the charge pump output that is connected to theLED anodes. A small 1mF ceramic bypass capacitor isrequired between the VOUT pin and ground near the device.GND is the ground reference for the charge pump. The pinmust be connected to the ground plane on the PCB.
C1+, C1− are connected to each side of the ceramic bucketcapacitor C1.
C2+, C2− are connected to each side of the ceramic bucketcapacitor C2.
LED1 to LED4 provide the internal regulated currentsource for each of the LED cathodes. These pins enterhigh−impedance zero current state whenever the device isplaced in shutdown mode. If an LED pin is directly tied toVOUT, that channel is disabled.
TAB is the exposed pad underneath the package. For bestthermal performance, the tab should be soldered to the PCBand connected to the ground plane.
RSET is connected to the resistor (RSET) to set the currentfor the LEDs. The voltage at this pin regulated to 0.6 V. Theground side of the external resistor should be star connectedback to the GND of the PCB. In shutdown mode, RSETbecomes high impedance.
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CAT3604V
Block Diagram
C1−C1+C2−C2+VINVIN1x mode (LDO)1.33x, 1.5x, 2x Charge PumpVOUTMode Control1, 1.3 MHzOscillatorENReferenceVoltageRSETLED1LED2LED3LED4CurrentSettingLED ChannelCurrent RegulatorsGNDFigure 25. CAT3604V Functional Block Diagram
Basic Operation
At power−up, the CAT3604V starts operating in 1x modewhere the output will be approximately equal to the inputsupply voltage (less any internal voltage losses). If theoutput voltage is sufficient to regulate all LED currents, thedevice remains in 1x operating mode.
If the input voltage is insufficient or falls to a level wherethe regulated currents cannot be maintained, the deviceautomatically switches into 1.33x mode (after a fixed delaytime of about 400 ms). In 1.33x mode, the output voltage isapproximately equal to 1.33 times the input supply voltage(less any internal voltage losses).
This sequence repeats in the 1.33x and 1.5x mode until thedriver enters the 2x mode. In 1.5x mode, the output voltageis approximately equal to 1.5 times the input supply voltage.While in 2x mode, the output is approximately equal to 2times the input supply voltage.
If the device detects a sufficient input voltage is present todrive all LED currents in 1x mode, it will changeautomatically back to 1x mode. This only applies forchanging back to the 1x mode. The difference between theinput voltage when exiting 1x mode and returning to 1xmode is called the 1x mode transition hysteresis (VHYS) andis about 500 mV
LED Current Selection
The EN pin enables and disables the device. The LEDdriver enters a “zero current” shutdown mode if EN is heldlow for 1.5 ms or more.
As soon as the EN input goes low, all LED channels areinstantly disabled, where the LED current is set to zero. Aslong as the CAT3604V is not in shutdown mode, the LEDsturn on as soon as the EN goes high.
Unused LED Channels
For applications not requiring all the channels, it isrecommended to connect the unused LED pins directly toVOUT (see Figure 26).
1 mFC1+VIN1 mFVINCIN1 mFONOFFRSETC1−C2+C2−VOUTCAT3604VCOUTLED1LED2LED3LED41 mF
ENRSETGNDThe LED current is set to by the external resistor RSET asfollows:
LEDcurrent+132
0.6VRSET
Figure 26. Application with 3 LEDs
Protection Mode
If an LED is disconnected, the device senses that, run thediagnostics, then ignores that channel and goes back to themost effective mode. When all LEDs are disconnected, the
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CAT3604VHV4-GT2
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