MP24895GQ-Z

MP24895 Step-down White-LED Driver Wide 6-36V Input Voltage The Future of Analog IC Technology DESCRIPTION FEATURES The MP24895 is step-down LED driver, which is designed in continuous current mode for driving the high-brightness LEDs from a wide input voltage of 6V to 36V. • • • • • • • • • The MP24895 employs a hysteretic control scheme to regulate LED current. Moreover, the control scheme provides optimal loop stabilization and a very quick response time. For a high accuracy, the MP24895 senses LED current by an external high-side resistor. Its low 100mV average feedback voltage reduces power loss and improves the efficiency. Internal 36V MOSFET Wide 6V-to-36V Input Range 1A Output Current High Efficiency Hysteretic Control PWM and Analog Dimming 1000:1 PWM Dimming Resolution UVLO, Thermal Shutdown Available in TSOT23-5 and Packages QFN-6 APPLICATIONS • • • • • The MP24895 implements PWM and analog dimming together on the EN/DIM pin. The MP24895 includes under-voltage lockout,t and thermal overload protection to prevent damage in the event of an output overload. 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 Products, Quality Assurance page. The MP24895 is available in TSOT23-5 and QFN-6 packages. “MPS” and “The Future of Analog IC Technology” are registered trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION D VIN 6 – 36V R SENSE CIN IN RS L MP24895 EN/DIM MP24895 Rev. 1.0 8/6/2015 GND SW www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 1 MP24895 – STEP-DOWN WHITE-LED DRIVER WITH 6-36V INPUT VOLTAGE ORDERING INFORMATION Part Number* Top Marking MP24895GJ* Package TSOT23-5 MP24895GQ** QFN-6 (3x3mm) AKD AKD * For Tape & Reel, add suffix –Z (e.g. MP24895GJ–Z); * *For Tape & Reel, add suffix –Z (e.g. MP24895GQ–Z); PACKAGE REFERENCE TSOT23-5 QFN-6 (3x3mm) ABSOLUTE MAXIMUM RATINGS (1) Thermal Resistance VIN, VSW ........................................ -0.3V to +40V VRS ................................................. VIN-5V to VIN All Other Pins .............................. -0.3V to +6.3V Continuous Power Dissipation (TA = +25°C) (2) TSOT23-5 ..................................................1.1W QFN-6 (3x3mm) .........................................2.5W Junction Temperature .............................. 150°C Lead Temperature ................................... 260°C Storage Temperature ............... -65°C to +150°C TSOT23-5 ............................ 110 ..... 55 ... °C/W QFN-6 (3x3mm) .................... 50 ...... 14 ... °C/W Recommended Operating Conditions (3) Supply Voltage VIN ............................. 6V to 36V Operating Junction Temp. (TJ). ... -40°C to +125°C MP24895 Rev. 1.0 8/6/2015 (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 board. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 2 MP24895 – STEP-DOWN WHITE-LED DRIVER WITH 6-36V INPUT VOLTAGE ELECTRICAL CHARACTERISTICS (6) VIN = 24V, TJ =-40°C to 125°C , unless otherwise noted. Parameter Symbol Condition Min Input Voltage IN Under-Voltage Lockout Under-Voltage Lockout Hysteresis Shutdown Supply Current Quiescent Supply Current VIN VIN UVLO VIN Rising 6 4.7 ISD IQ No Switching Feedback Reference Voltage (with respect to VIN) VIN-VRS ForTj=25°C, VEN/DIM=1.28V EN/DIM Enable High Voltage VEN For Tj=-40°C to 125°C VEN/DIM=1.28V VEN Rising EN/DIM Enable Hysteresis EN/DIM Pull-Up Resistor Internal Reference Voltage Switch On Resistance (5) Minimum On Time VEN HYS REN VREF RDS ON tON MIN (5) Minimum Off Time (5) Thermal Shutdown Temperature Thermal Shutdown Hysteresis (5) HIGH 94 Typ Max Units 36 5.9 5.3 700 170 0.7 250 1.1 V V mV µA mA 100 106 mV 108 mV 92 0.19 0.25 0.31 V 90 1.24 50 45 1.28 0.2 100 mV kΩ V Ω ns VEN/DIM=0.3V 1.32 0.4 tOFF_MIN 80 ns TOTP 150 °C TOTP HYS 15 °C Notes: 5) Guaranteed by design 6) Not test in production, guaranteed by characterization. Typical value represent the most likely parametric norm at +25°C MP24895 Rev. 1.0 8/6/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 3 MP24895 – STEP-DOWN WHITE-LED DRIVER WITH 6-36V INPUT VOLTAGE TYPICAL CHARACTERISTICS VIN =18V, VOUT =10V, L =47µH, TA = 25°C, unless otherwise noted. VIN UVLO EN UVLO VRS 101.0 0.250 5.50 100.8 5.45 100.6 0.248 5.40 100.4 5.25 5.20 0.246 VRS(mV) 5.30 UVLO(V) UVLO(V) 5.35 0.244 100.2 100.0 99.8 99.6 5.15 5.10 99.4 0.242 99.2 5.05 5.00 -60 -40 -20 0 20 40 60 80100120140 0.240 -60 -40 -20 0 20 40 60 80100 120140 RDSON 99.0 -60 -40 -20 0 20 40 60 80 100120140 Reference Voltage 0.50 1.280 0.45 0.40 1.278 0.35 VREF(V) 0.30 0.25 0.20 1.276 1.274 0.15 0.10 1.272 0.05 0 -60 -40 -20 0 20 40 60 80 100120140 MP24895 Rev. 1.0 8/6/2015 1.270 -60 -40 -20 0 20 40 60 80 100120 140 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 4 MP24895 – STEP-DOWN WHITE-LED DRIVER WITH 6-36V INPUT VOLTAGE TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 18V, VOUT = 10V, L =47µH, TA = 25ºC, unless otherwise noted. Analog Dimming 1000 98 900 96 800 LED CURRENT (mA) 100 94 92 90 88 86 84 82 80 10 PWM Dimming 1200 LED CURRENT (mA) Efficiency Test 700 600 500 400 300 200 MP24895 Rev. 1.0 8/6/2015 20 25 VIN (V) 30 35 0 0 800 600 400 200 100 15 1000 0.5 1 1.5 VADIM (V) 2 2.5 0 0 10 20 30 40 50 60 70 80 90100110 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 5 MP24895 – STEP-DOWN WHITE-LED DRIVER WITH 6-36V INPUT VOLTAGE TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 18V, VOUT = 10V, L =47µH, TA = 25ºC, unless otherwise noted. Steady State VIN Start-up VSW 10V/div. VSW 10V/div. IL 500mA/div. VEN/DIM 2V/div. VSW 10V/div. VEN/DIM 1V/div. VIN 10V/div. IL 1A/div. ILED 500mA/div. IL 500mA/div. Analog Dimming PWM Dimming VEN/DIM = 0.9V fPWM = 2kHz, DPWM = 50% VSW 10V/div. VSW 10V/div. VPWM 5V/div. IL 500mA/div. IL 500mA/div. Short Protection VSW 10V/div. VEN/DIM 1V/div. VEN/DIM 500mV/div. VIN 20V/div. VEN Start-up IL 500mA/div. Open Protection Over-Temperature Protection TA = 125 C VSW 10V/div. VSW 10V/div. IL 500mA/div. ILED 500mA/div. MP24895 Rev. 1.0 8/6/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 6 MP24895 – STEP-DOWN WHITE-LED DRIVER WITH 6-36V INPUT VOLTAGE PIN FUNCTIONS TSOT23-5 Pin# QFN-6 (3x3mm) Pin# 1 1 SW 2 2 GND Name Description Drain of Internal MOSFET. Connect the inductor common terminal and Schottky anode to this pin. Ground. Enable/Dimming Command Input. For PWM dimming, apply a square wave signal to this pin. For analog dimming, apply a 0.3V-to-2.5V DC voltage to EN/DIM linearly control the LED current range from 25% to 200%. Turn off the output current when pulling this pin below 0.2V. Leave it open for normal operation (VEN/DIM=1.28V). 3 5 4 4 RS LED Current Sense Input. Connect a current-sense resistor to program the LED average current to IN pin. 5 3 IN Input Supply Pin. Connect an appropriate decoupling capacitor from the IN pin to GND. 6 N/C MP24895 Rev. 1.0 8/6/2015 Not Connected. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 7 MP24895 – STEP-DOWN WHITE-LED DRIVER WITH 6-36V INPUT VOLTAGE FUNCTION DIAGRAM D VIN Rsense CIN IN RS HV Regulator 5V 1.275V Reference High Side Current Sense L SW 0.2V Enable + DIM EN /DIM Filter PWM + Driver R1 R2 GND Figure 1: MP24895 Functional Block Diagram MP24895 Rev. 1.0 8/6/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 8 MP24895 – STEP-DOWN WHITE-LED DRIVER WITH 6-36V INPUT VOLTAGE OPERATION Steady State The MP24895 is a hysteretic-controlled, stepdown LED driver that is easily configured for various applications with an input range from 6V to 36V. The converter employs a high-side current-sense resistor to detect and regulate the LED current. The voltage across the currentsense resistor is measured and regulated to within 100mV±20mV. The internal 1.275V reference voltage provides a 0.2V reference to enable the part and a 1.275V pull-up voltage as current reference. When VEN>0.2V, the output of the comparator goes high and the other blocks are enabled. System Soft Start 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 for soft-start. Dimming Control MP24895 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-to-2.5V DC voltage to this pin. A high-side resistor, RSENSE, senses the output current. When the switch is on, R2 is shorted and R1 sets the output current upper-threshold. When the switch is off, R1 and R2 set the output current lower-threshold, and the ratio of R1 and R2 determines the current hysteresis. Enable Control Once Input voltage is applied, the internal 1.275V reference is connected to EN/DIM pin through pull up resistor. If the EN/DIM pin is left open, the IC automatically starts up to the maximum brightness. Adding a capacitor to this pin can hereby program a soft-start time. Applying an external voltage range from 0.2V to 1.25V to the EN/DIM pin linearly controls the current-sense voltage reference from 0mV to 100mV for analog dimming. Applying an external PWM voltage with an amplitude of 1.25V to the EN/DIM pin achieves PWM dimming. For additional information on the flexible external PWM dimming method, please refer to the “Selecting Dimming Control Mode” section. MP24895 Rev. 1.0 8/6/2015 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2015 MPS. All Rights Reserved. 9 MP24895 – STEP-DOWN WHITE-LED DRIVER WITH 6-36V INPUT VOLTAGE APPLICATION INFORMATION Setting the LED Current The LED current is set by the current-setting resistor between the IN and RS pins, where: RSET=100mV/ILED For RSET=0.2Ω, the LED current is set to 500mA Selecting the Inductor Lower value of the inductor results in higher switching frequencies, leading to larger switch loss. For most applications, select a switching frequency between 200kHz and 600kHz. Estimate the inductor value based on the desired switching frequency, where: V (1- OUT ) × VOUT VIN L= 0.4 × ILED × fSW Selecting Soft-Start Capacitor The delay time with the soft-start capacitor can be estimated by 0.2ms/nF. In PWM dimming, select a C