TS19378CS RLG

TS19378 Taiwan Semiconductor 2A Buck (Step-down) WLED Driver DESCRIPTION FEATURES The TS19378 is a high voltage step-down converter ● Input Voltage Range 8V~40V designed for driving up to 10 series white LEDs from a ● Output voltage up to 38V 40V system input. The total LED driving current up to ● 2A Switch Output Current 2A, which is measured through an external current ● Duty ratio: 0%~100% PWM control sense resistor. Its low 200mV feedback voltage ● 300kHz Switching Frequency reduces power loss and improves efficiency. The OVP ● Enable/Disable Functions pin monitors the output voltage and turns off the ● Soft Start Time Control converter if an over-voltage condition is present due to ● Current limit and Thermal Shutdown an open circuit condition. The TS19378 includes ● Short Circuit Protections current limit, short circuit protection and thermal ● Built-in Internal SW P-CH MOSFET shutdown protection preventing damage. TS19378 provides high power, high efficiency, and APPLICATION excellent transient characteristics. The PWM control ● White LED Backlighting circuit is able to the duty ratio linearly from 0 up to ● High Power LED Application 100%. Since this converter can accommodate an ● Multiple LED Driving input voltage up to 40V, it is also suitable for the ● LED Lighting Equipment operation via an AC adapter. SOP-8EP Pin Definition: 1. EN/SS 2. GND 3. VGATE 4. VCC 8. COMP 7. FB 6. OVP 5. SW (Connected to exposed pad) Notes: Moisture sensitivity level: level 3. Per J-STD-020 TYPICAL APPLICATION CIRCUIT Document Number: DS_P0000199 1 COUT ESR Range R2 C7 30~80mΩ 470R 10nF 80~300mΩ 100R 15nF Version: B15 TS19378 Taiwan Semiconductor ABSOLUTE MAXIMUM RATINGS (TA = 25°C unless otherwise specified) (Note 1) PARAMETER SYMBOL LIMIT UNIT VCC Pin Voltage VCC VSS - 0.3 to VSS + 45 V Feedback Pin Voltage VFB VSS - 0.3 to 6 V EN/SS Pin Voltage VEN/SS VSS - 0.3 to 6 V OVP Pin Voltage VOVP VSS - 0.3 to VCC V COMP Pin Voltage VCOMP VSS - 0.3 to 6 V VGATE Pin Voltage VGATE VSS - 0.3 to VCC V Switch Pin Voltage VSW VSS - 0.3 to VCC + 0.3 V Power Dissipation PD Internally limited mW Storage Temperature Range TST -65 to +150 °C Operating Junction Temperature Range TOJP -40 to +125 °C Operating Supply Voltage VOP 8 to 40 V Output Voltage VOUT 38 V SYMBOL LIMIT UNIT RӨJC 15 o 40 o THERMAL PERFORMANCE (Note 2) PARAMETER Thermal Resistance from Junction to Case Thermal Resistance from Junction to Ambient RӨJA C/W C/W ELECTRICAL SPECIFICATIONS (TA = 25°C unless otherwise specified) PARAMETER SYMBOL CONDITION MIN TYP MAX UNIT 0.19 0.20 0.21 V Feedback Voltage VFB IOUT=0.2A Quiescent Current ICCQ VFB=0.5V force driver off -- 3 6 mA Feedback Bias Current IFB IOUT=0.1A -- 0.1 0.5 μA Shutdown Supply Current ISD VEN =0V -- 150 300 μA ISWLIMIT 2.5 -- -- A Oscillation Frequency fOSC 240 300 360 kHz Short Frequency fOSC -- 50 -- kHz Low (regulator OFF) -- -- 0.8 V Switch Current Limit EN/SS Pin Shutdown Logic input threshold voltage VSL EN/SS Pin Input Current IEN/SS VEN=0V -- 5 -- μA Internal MOSFET RDSON RDSON VCC=5V, VFB=0V -- 130 180 mΩ OVP Sense Voltage VOVP 0.833 0.850 0.867 V Thermal shutdown Temp TSD -- 150 -- °C Thermal shutdown Hysteresis TSH -- 40 -- °C Note: 1. Stresses listed as the above “Absolute Maximum Ratings” may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. 2. RӨJA is measured with the PCB copper area(need connect to Exposed Pad) of approximately 1.5 in2(Multi-layer). Document Number: DS_P0000199 2 Version: B15 TS19378 Taiwan Semiconductor ORDERING INFORMATION PART NO. TS19378CS RLG PACKAGE PACKING SOP-8EP 2,500pcs / 13” Reel Note: 1. Compliant to RoHS Directive 2011/65/EU and in accordance to WEEE 2002/96/EC. 2. Halogen-free according to IEC 61249-2-21 definition. FUNCTION BLOCK PIN DESCRIPTION PIN NO. NAME FUNCTION 1 EN/SS 2 GND 3 VGATE Gate drive for external N-CH MOSFET. 4 VCC Power supply pin for all internal circuitry. 5 SW SW is the output of the internal driver switch. Connected for package exposed pad 6 OVP Output voltage protection. 7 FB 8 COM EN: Output stage enable control pin. It can be left floating for normally on. SS: Supplied shutdown or soft start function. Ground return for all internal circuitry. Feedback pin. Reference voltage is VFB=0.2V. Output pin of error amplifier. Document Number: DS_P0000199 3 Version: B15 TS19378 Taiwan Semiconductor TYPICAL APPLICATION CIRCUIT AC Input Application Circuit ILED R5 350mA 750mA 1000mA 0.570Ω 0.266Ω 0.200Ω 70mW 150mW 200mW C1 L1 100μF 220μF 330μF 33μH APPLICATION INFORMATION PWM Control The TS19378 consists of DC/DC converters that employ a pulse-width modulation (PWM) system. In converters of the TS19378, the pulse width varies in a range from 0 to 100%, according to the load current. The ripple voltage produced by the switching can easily be removed through a filter because the switching frequency remains constant. Therefore, these converters provide a low-ripple power over broad ranges of input voltage and load current Setting ILED Current Application circuit item shows the basic application circuit with TS19378 adjustable output version. The external resistor sets the LED output current according to the following formula: ILED=(0.25V/R5), VFB=0.2V Resistor select for LED output current setting ILED R2 350mA 0.57Ω 70mW 750mA 0.266Ω 150mW 1000mA 0.2Ω 200mW Current Limit The current limit threshold is setting by the internal circuit. Compensation In all LED driver applications. Connecting a resistor (R2) and a capacitor (C7) from COMP pin to GND. Please refer the application circuit table to design. Document Number: DS_P0000199 4 Version: B15 TS19378 Taiwan Semiconductor APPLICATION INFORMATION (CONTINUE) EN/SS This pin can be supplied shutdown or soft start function. It is inside pull high function. For normal application, the pin must be connected a capacitor to ground. There is a 5μA current to charge this capacitor, vary the different capacitor value to control soft start time. Allow the switching regulator circuit to be shutdown pulling this pin below a 0.8V threshold voltage; the shutdown supply current is approximately 150μA Inductor Selection For most designs, the different frequency can be reducing the inductor value; The TS19378 is suggested 33μH. Where is inductor Ripple Current. Large value inductors lower ripple current and small value inductors result in high ripple currents. Choose inductor ripple current approximately 20% of the maximum load current 2A, ΔIL=0.4A. The DC current rating of the inductor should be at least equal to the maximum load current plus half the ripple current to prevent core saturation (2A+0.2A). Input Capacitor Selection This capacitor should be located close to the IC using short leads and the voltage rating should be approximately 1.5 times the maximum input voltage. The RMS current rating requirement for the input capacitor of a buck regulator is approximately 1⁄2 the DC load current. A low ESR input capacitor sized for maximum RMS current must be used. A 220µF low ESR capacitor for most applications is sufficient. Over Voltage Protection The OVP voltage is set by outside resistance (R1 and R4). The external resistor sets the OVP voltage according to the following equation: R4 ) R1 If VOVP >0.85V, The OVP is happened that to disable the driver until VOVP