MP2489DJ-LF-Z

MP2489 Step Down White LED Driver with Wide 6V–60V Input Voltage The Future of Analog IC Technology DESCRIPTION FEATURES The MP2489 is a high efficiency step-down converter designed in continuous current mode for driving the high brightness Light Emitting Diodes (LED) from wide input voltage 6V–60V. • • • • • • • • • • • The MP2489 employs hysteretic control architecture to regulate a high accuracy LED current, which is measured through an external high-side current sensing resistor. Moreover, this control scheme provides optimized circuit stabilization and very quick response time without the loop compensation. Its low 202mV average feedback voltage reduces power loss and improves the converter efficiency. Internal 65V MOSFET Wide 6V to 60V Input Range ≥1A Output Current High Efficiency (>95%) Hysteresis Control PWM & Analog Dimming 1000:1 PWM Dimming Resolution Thermal Shutdown Inherent Open LED Protection Short LED Protection Available in TSOT23-5, QFN6(3x 3mm) and SOIC8E Packages APPLICATIONS The MP2489 implements PWM and analog dimming together with DIM pin. • • • • • The MP2489 includes thermal overload protection preventing damage in the event of an output overload. The MP2489 is available in small QFN6 (3x 3mm), TSOT23-5 and SOIC8E packages. Low Voltage Halogen Replacement Low Voltage General Illumination Automotive/Decorative LED Lighting Signs/Emergency Lighting LED Backlighting All MPS parts are lead-free and adhere to the RoHS directive. For MPS green status, please visit MPS website under Quality Assurance. “MPS” and “The Future of Analog IC Technology” are Registered Trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION D1 VIN RSENSE CIN IN RS L1 MP2489 EN/DIM GND MP2489 Rev. 1.23 10/11/2012 SW www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2012 MPS. All Rights Reserved. 1 MP2489 – STEP DOWN WLED DRIVER WITH WIDE 6V–60V INPUT VOLTAGE ORDERING INFORMATION Part Number MP2489DJ* MP2489DQ MP2489DN Package TSOT23-5 QFN6 (3x 3mm) SOIC8E Top Marking AAD 9Y MP2489 * For Tape & Reel, add suffix –Z (e.g. MP2489DJ–Z); For RoHS Compliant Packaging, add suffix –LF (e.g. MP2489DJ–LF–Z) PACKAGE REFERENCE TOP VIEW SW 1 8 IN GND 2 7 GND GND 3 6 GND EN/DIM 4 5 RS EXPOSED PAD ON BACKSIDE CONNECT TO GND TSOT23-5 QFN6 (3x 3mm) SOIC8E ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance VIN, VSW .........................................-0.3V to +65V VRS ..................................................VIN-5V to VIN All Other Pins ...............................-0.3V to +6.3V Continuous Power Dissipation (TA = +25°C) (2) TSOT23-5 .................................................. 1.3W QFN6 ......................................................... 2.5W SOIC8E...................................................... 2.6W Junction Temperature ...............................150°C Lead Temperature ....................................260°C Storage Temperature............... -65°C to +150°C TSOT23-5 .............................100 ..... 55 ... °C/W QFN6 (3mm x 3mm) ..............50 ...... 14 ... °C/W SOIC8E ..................................48 ...... 10 ... °C/W Recommended Operating Conditions (3) Supply Voltage VIN ..............................6V to 60V Operating Junction Temp. (TJ). -40°C to +125°C MP2489 Rev. 1.23 10/11/2012 (4) θJA θJC Notes: 1) Exceeding these ratings may damage the device. 2) The maximum allowable power dissipation is a function of the maximum junction temperature TJ(MAX), the junction-toambient thermal resistance θJA, and the ambient temperature TA. The maximum allowable continuous power dissipation at any ambient temperature is calculated by PD(MAX)=(TJ(MAX)TA)/ θJA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage. 3) The device is not guaranteed to function outside of its operation conditions. 4) Measured on JESD51-7, 4-layer PCB. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2012 MPS. All Rights Reserved. 2 MP2489 – STEP DOWN WLED DRIVER WITH WIDE 6V–60V INPUT VOLTAGE ELECTRICAL CHARACTERISTICS VIN = 24V, TA = +25°C, unless otherwise noted. Parameter Input Voltage Shutdown Supply Current Quiescent Supply Current Internal Reference Voltage Symbol Condition VIN ISD IQ No Switching IREF Min 6 Feedback Reference Voltage (with respect to VIN) VIN-VRS 192 VEN/DIM = 1.28V Feedback Reference Voltage VFB_HYS Hysterisis EN/DIM Max Dimming Voltage VDIM_MAX EN/DIM Mim Dimming Voltage VDIM_MIN EN/DIM Enable High Voltage VEN_HIGH VEN Rising EN/DIM Enable Low Volatge VEN_LOW VEN Falling EN/DIM Up-pulling Resistor REN Recommended PWM Dimming FPWM Frequency Switch On Resistance RDS_ON Minimum On Time TON_MIN Minimum Off Time TOFF_MIN Recommended Maximum FMAX Operating Frequency Recommended Duty Cycle Range D at FMAX External capacitor on dim Start Up Time TSS pin is 4.7nF MP2489 Rev. 1.23 10/11/2012 Typ Max 60 108 1 Units V µA mA V 212 mV 1.275 202 ±30 mV 2.56 0.3 V V V V kΩ 2 kHz 0.3 0.16 45 0.1 0.5 100 100 30 0.3 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2012 MPS. All Rights Reserved. Ω ns ns 600 kHz 70 % ms 3 MP2489 – STEP DOWN WLED DRIVER WITH WIDE 6V–60V INPUT VOLTAGE PIN FUNCTIONS TSOT23-5 Pin# QFN6 Pin# 1 1 2 2, 5 3 3 4 4 5 6 MP2489 Rev. 1.23 10/11/2012 SOIC8 Pin# Name Description The Drain of Internal MOSFET. Connecting the common terminal of inductor and anode of Schottky to this pin. 2,3,6,7 GND Ground. Enable/Dimming Command Input. To use PWM dimming, apply a square wave signal to this pin. To use Analog dimming, apply a 0.3V–2.5V DC voltage to this pin. The voltage from 0.3V to 2.5V linearly controls the 4 EN/DIM LED current range from 25% to 200%. Turn off the output current when pulling this pin below 0.2V. Connect a 1nF–10nF capacitor for normal operation (VEN/DIM=1.28V). LED Current Sense Input. Connecting the current sensing resistor that 5 RS programs the LED average current to IN pin. Input Supply Pin. Connecting a proper decoupling capacitor from IN pin 8 IN to GND. 1 SW www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2012 MPS. All Rights Reserved. 4 MP2489 – STEP DOWN WLED DRIVER WITH WIDE 6V–60V INPUT VOLTAGE TYPICAL PERFORMANCE CHARACTERISTICS VIN=30V, 3 LEDS in series, IOUT=550mA, unless otherwise noted. Analog Dimming Curve OUTPUT CURRENT (A) EFFICIENCY (%) 1.2 1.2 95 90 85 80 75 70 ILED vs. Rset 10 20 30 40 50 60 1 1 0.8 0.8 ILED(A) 100 Efficiency vs. Input Voltage 0.6 0.4 0.4 0.2 0.2 00 INPUT VOLTAGE (V) 0.5 1 1.5 2 2.5 0 0.1 Vin Startup 0.3 0.5 0.7 0.9 Ven Startup VEN 1V/div. VIN 20V/div. EN Signal 2V/div. ILED 500mA/div. ILED 500mA/div. PWM Dimming Open LED Protection Short LED Protection fPWM = 200Hz, DPWM= 50% Open LEDs at working Short LEDs at working VSW 20V/div. PWM Signal 2V/div. ILED 500mA/div. MP2489 Rev. 1.23 10/11/2012 1.1 VSW 20V/div. Vsw 20V/div. ILED 200mA/div. 3 ANALOG DIM (V) Steady State VSW 10V/div. 0.6 VSW 20V/div. VLED+ 10V/div. ILED 200mA/div. VSW 20V/div. VLED10V/div. ILED 200mA/div. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2012 MPS. All Rights Reserved. 5 MP2489 – STEP DOWN WLED DRIVER WITH WIDE 6V–60V INPUT VOLTAGE FUNCTION DIAGRAM D VIN Rsense CIN IN RS 5 4 HV Regulator 5V 1.275V Reference High Side Current Sense L 1 0.2V SW Enable + DIM EN /DIM 3 Filter PWM + Driver R1 R2 GND 2 Figure 1—MP2489 Function Block Diagram MP2489 Rev. 1.23 10/11/2012 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2012 MPS. All Rights Reserved. 6 MP2489 – STEP DOWN WLED DRIVER WITH WIDE 6V–60V INPUT VOLTAGE OPERATION Steady State System Soft Start The MP2489 is a hysteretic controlled step down LED driver that is easily to be configured in varies applications ranging from 6V–60V input. The converter employs a high side current sensing resistor to detect and regulate the LED current. The voltage across the current sensing resistor is kept measured and regulated in 202mV±30mV range. The voltage on the EN/DIM pin is the inductor current reference. An external capacitor from the EN/DIM pin to ground provides a soft-start delay. When VIN starts, internal voltage source charges the capacitor from 0V to 1.25V to fulfill soft-start function. The internal 1.275V reference voltage is utilized to provide a 0.2V reference for enabling the part and a 1.275V pulling-up voltage as current reference voltage. When VEN>0.2V, the output of the comparator becomes high and the other blocks are enabled. Output current is sensed by high-side resistor Rsense. When the switch is on, R2 is shorted and output current upper-threshold is fixed by R1. When the switch is off, output current lowerthreshold is fixed by R1 and R2. Ratio of R1 and R2 determines the current hysteresis. Dimming Control MP2489 provides two dimming methods: PWM dimming and DC analog dimming. To use PWM dimming, apply a square wave to the EN/DIM pin. To use analog dimming, apply a 0.3V–2.5V DC voltage to this pin. Maximum Continuous Switching Current MP2489 max continuous switching current depends on the package with different thermal resistance. The table 1 shows the max continuous current corresponding package for reference. Table 1. Imax vs. package Enable Control Once Input voltage is applied, the internal 1.275V reference is connected to EN/DIM pin through pull up resistor. If EN/DIM is left open, the IC will automatically start up to the maxim brightness. Appling a capacitor on this pin can hereby program a soft start time. Package TSOT23-5 QFN6 SOIC8E Imax(A) 1.00 1.41 1.44 If an external voltage range from 1.275V to 1.25V is applied to this pin, the current sensing voltage reference is linearly controlled from 0mV to 202mV. By controlling the EN/DIM pin voltage the analog dimming can be easily employed. If an external PWM voltage is applied on this pin, the IC will follow the PWM duty to achieve the PWM dimming, the PWM signal amplitude must be about 1.25V. About the flexible external PWM dimming method, please refer to the selecting dimming control mode section. MP2489 Rev. 1.23 10/11/2012 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2012 MPS. All Rights Reserved. 7 MP2489 – STEP DOWN WLED DRIVER WITH WIDE 6V–60V INPUT VOLTAGE APPLICATION INFORMATION Setting the LED Current The LED current is identical and set by the current setting resistor between the IN pin and RS pin. RSET=202mV/ILED inductor current reference directly and linearly controls the inductor current range from 25% to 200%. (See Figure 2) VIN 6 IN TP4 EN/DIM For RSET=0.36Ω, the LED current is set to 550mA Selecting the Diode The output diode supplies current to the inductor when the internal MOSFET is off. To reduce losses due to diode forward voltage and recovery time, use a Schottky diode with the MP2489. The diode should be rated for a reverse voltage greater than the input voltage. The average current rating must be greater than the maximum load current expected, and the peak current rating must be greater than the peak inductor current. Selecting the Input Capacitor The input capacitor reduces the surge current drawn from the input supply and the switching noise from the device. A 10µF–22µF capacitor is enough for most application. The voltage rating should be greater than input voltage. A low ESR capacitor should be used for input decoupling. Selecting the Output Capacitor For most applications, output capacitor is not necessary. But if peak to peak ripple LED current is required less than 30% of average current, add a capacitor across the LEDs. Proportionally lower ripple can be achieved with higher capacitor value. A value of 2.2µF will meet most requirements. Selecting Soft-Start Capacitor With the soft-start capacitor, the delay time can be estimated by 0.2ms/nF. In PWM dimming, C