CAT4101 - 1 A Constant-Current LED Driver with …

1 Semiconductor Components Industries, LLC, 2012 July, 2012 Rev. 81 Publication Order Number: CAT4101 /DCAT41011 A Constant-Current LEDD river with PWM DimmingDescriptionThe CAT4101 is a constant current sink driving a string ofhigh brightness LEDs up to 1 A with very low dropout of V at fullload. It requires no inductor, provides a low noise operation andminimizes the number of components. The LED current is set by anexternal resistor connected to the RSET pin. The LED pin iscompatible with high voltage up to 25 V, allowing the driving of longstrings of LEDs. The device ensures an accurate and regulated currentin the LEDs independent of supply and LED forward PWM/EN input allows the device shutdown and the LEDbrightness adjustment by using an external pulse width modulation(PWM)

2 Driver features a thermal shutdown protection that becomesactive whenever the die temperature exceeds 150 device is available in a high power, 5 lead TO 263 packageoffering excellent thermal dissipation Accurate 1 A current Sink Up to 25 V Operation on LED Pin Low Dropout 500 mV at 1 A LED current Set by External Resistor High Resolution PWM Dimming via EN/PWM Zero current Shutdown Mode Thermal Shutdown Protection TO 263 (D2 PAK) 5 lead Package This Device is Pb Free, Halogen Free/BFR Free and is RoHSCompliantApplications High Power LED up to 1 A Architectural and General Lighting Automotive LightingFigure 1. Typical Application CircuitVINCAT4101 VCCLEDs549 W3 V to 25 VVIN5 VEN/PWMRSETLEDGNDONOFF1 5(TO 263, 5 LEAD)TV SUFFIXCASE 418 AHPIN CONNECTIONSMARKING DIAGRAM(Top View)DevicePackageShipping ORDERING INFORMATIONCAT4101TV T75TO 263(D2 PAK, 5 Lead)(Pb Free)750 /Tape & Reel1EN/PWMVINGNDRSETLEDTAB For information on tape and reel specifications,including part orientation and tape sizes, pleaserefer to our Tape and Reel Packaging SpecificationBrochure, BRD8011 = Specific Device CodeXXXXXXXXX = Internal TraceabilityCAT4101 1.

3 ABSOLUTE MAXIMUM RATINGSP arameterRatingUnitsVIN, RSET, EN/PWM Voltages6 VLED Voltage25 VStorage Temperature Range 65 to +150_CJunction Temperature Range 40 to +150_CLead Temperature300_CStresses 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 2. RECOMMENDED OPERATING CONDITIONSP arameterRatingUnitsVIN to Pin Voltagedevice enabled, continuous operationdevice disabled or transient when enabledUp to 6Up to 25 VAmbient Temperature Range 40 to +85_CLED Pin CurrentUp to 1 ANOTE:Typical application circuit with external components is shown on page For additional temperature options, please contact your nearest ON Semiconductor Sales 3.

4 ELECTRICAL OPERATING CHARACTERISTICS (Min and Max values in bold are over recommended operatingconditions unless specified otherwise. Typical values are at VIN = V, TAMB = 25 C)SymbolParameterConditionsMinTypMaxUnit sILED ACCLED current AccuracyVLED = 1 V, RSET = kW315350385mAVLED = 1 V, RSET = 750 W700 VLED = 1 V, RSET = 549 W1000 VDOUTD ropout VoltageILED = 1 A500mVVRSETRSET Pin CurrentNo LED, RSET = LED, RSET = 549 CurrentVEN = 0 V1mAREN/PWMVHIVLOEN/PWM Pin Pull down resistance Logic High Level Logic Low Shutdown150_CTHYST hermal Hysteresis20_CILED/IRSETRSET to LED current gain ratio100 mA LED current400 VUVLOU ndervoltage lockout (UVLO) 4. RECOMMENDED EN/PWM TIMING(For V VIN V, over full ambient temperature range 40 C to +85 C.)

5 SymbolNameConditionsMinTypMaxUnitsTPSTur n On time, EN/PWM rising to ILED fromShutdownILED = 1 AILED = 350 On time, EN/PWM rising to ILEDILED = 1 AILED = 350 mA920620nsTP2 Turn Off time, EN/PWM falling to ILEDILED = 1 AILED = 350 mA440310nsTRLED rise timeILED = 1 AILED = 350 mA840390nsTFLED fall timeILED = 1 AILED = 350 mA470350nsTLOEN/PWM low time1msTHIEN/PWM high time5msTPWRDWNEN/PWM low time to shutdown delay8msEN/PWMSHUTDOWNSHUTDOWNSHUTDOWN 0 mA0 mASHUTDOWN 0 mASHUTDOWNLED CURRENTVIN QUIESCENT CURRENT50%50%90%10%Figure 2. CAT4101 EN/PWM TimingTPSTP2TP1 TRTFTLOTHITPWRDWNILED = ( V / RSET) x 400EN/PWM OperationThe EN/PWM pin has two primary functions. Onefunction enables and disables the device.

6 The other functionturns the LED channel on and off for PWM dimmingcontrol. The device has a very fast turn on time (fromEN/PWM rising to LED on) and allows instant on whendimming LED using a PWM linear dimming is compatible with PWMfrequencies from 100 Hz to 5 kHz for PWM duty cycledown to 1%. PWM frequencies up to 50 kHz can besupported for duty cycles greater than 10%.When performing a combination of low frequencies andsmall duty cycles, the device may enter shutdown has no effect on the dimming accuracy, because theturn on time TPS is very short, in the range of 1 ensure that PWM pulses are recognized, pulse widthlow time TLO should be longer than 1 ms.

7 The CAT4101enters a zero current shutdown mode after a 5 ms delay(typical) when EN/PWM is held PERFORMANCE CHARACTERISTICS(VIN = 5 V, VCC = 5 V, VF = V, ILED = 1 A (1 LED), CIN = 1 mF, TAMB = 25 C unless otherwise specified.)Figure 3. Quiescent current vs. VIN Voltage(ILED = 0 mA)Figure 4. Quiescent current vs. LED CurrentINPUT VOLTAGE (V)LED current (mA) 5. Quiescent current vs. VIN Voltage(Full Load)Figure 6. LED current vs. LED Pin VoltageINPUT VOLTAGE (V)LED PIN VOLTAGE (V) 7. LED current Change vs. VIN VoltageFigure 8. LED current Change VOLTAGE (V)TEMPERATURE ( C) current (mA)QUIESCENT current (mA)QUIESCENT current (mA)LED current (A)LED current (A)LED current (A)No LoadFull PERFORMANCE CHARACTERISTICS(VIN = 5 V, VCC = 5 V, VF = V, ILED = 1 A (1 LED), CIN = 1 mF, TAMB = 25 C unless otherwise specified.)

8 Figure 9. RSET Pin Voltage vs. VIN VoltageFigure 10. RSET Pin Voltage vs. TemperatureINPUT VOLTAGE (V)TEMPERATURE ( C) 11. LED current vs. RSET ResistorFigure 12. PWM 200 Hz, 1% Duty CycleRSET (kW) 13. LED current vs. PWM Duty CycleFigure 14. EN/PWM Threshold vs. VINDUTY CYCLE (%)INPUT VOLTAGE (V) VOLTAGE (V)RSET VOLTAGE (V)LED current (A)LED current (%)ENABLE THRESHOLD (V)100 Hz1 kHz5 kHz50 kHz 40 C25 C85 CCAT4101 5. PIN DESCRIPTIONSNamePinFunctionEN/PWM1 Device enable (active high) and PWM supply input, connect to battery or resistor connected between this pin and ground sets the LED LED cathode Connect TAB to the Ground FunctionVIN is the supply pin for the device.

9 A small mF ceramicbypass capacitor is optional for noisy environments. Themaximum operating voltage is V. Whenever the inputsupply falls below the under voltage threshold, the currentsink will automatically be is the enable and one wire dimming input for theLED channel. Guaranteed levels of logic high and logic loware set at V and V respectively. When EN/PWM isinitially taken high, the device becomes enabled and theLED current is set at a gain of 400 times the current in place the device into zero current shutdown mode, theEN/PWM pin must be held low for 5 ms pin is connected to the bottom LED cathode andprovides a regulated current sink.

10 The pin enters ahigh impedance zero current state whenever the device isplaced in shutdown pin is connected to an external resistor to set the LEDcurrent. The ground side of the external resistor should bestar connected to the GND of the PCB. The pin sourcecurrent mirrors the current to the LED sink. The voltage atthis pin is regulated to is the ground reference for the device. The pin must beconnected to the ground plane on the is the exposed pad underneath the package. For bestthermal performance, the tab should be soldered to the PCBand connected to the ground DiagramFigure 15. CAT4101 Functional Block DiagramUndervoltage & ThermalLockoutShutdown DelayReference VoltageRSET Regulator & MirrorCurrentRegulatorVINGNDEN/PWMVINRSE TLEDB asic OperationThe CAT4101 has one highly accurate LED current sinkto regulate LED current in a string of LEDs.