OB3375CPA

OB3375 High performance buck LED driver GENERAL DESCRIPTION FEATURES The OB3375 is a high efficiency LED driver designed for white LEDS and for large LCDS backlight. OB3375 is built-in a quasi-resonant control method buck DC/DC converter. The controller implements a peak current mode control scheme and an internal transconductance amplifier to accurately control the output current over a wide input and load conditions. The transconductance amplifier reference is set by internal reference voltage and the duty cycle at HPWM pin. Low frequency LPWM dimming input that can accept an external control signal with a duty ratio of 1%-100%. OB3375 offers comprehensive protection features     protection, MOS drain LED+/LED- source short Programmable CC regulation PWM and PWM to analog combination  Zero voltage signal detected to improve efficiency and EMI performance            such as Diode & Inductor short protection, CS protection, Quasi-Resonant buck topology operation dimming to protect the system in various fault conditions open Low system cost and high efficiency short protection, LED-/GND short circuit protection, LED open loop protection, Over temperature protection (OTP). The cycle-by-cycle current limit function limits the maximum current flowing through the external LED+/LED- short circuit protection LED-/GND short circuit protection LED open loop protection Cycle-by-cycle current limiting Built-in leading edge blanking (LEB) VIN under voltage lockout with hysteresis Over temperature protection (OTP) Diode & Inductor short protection MOSFET drain source short protection CS open protection Low standby current MOSFET. APPLICATIONS OB3375 is offered in SOP8 package.  LED backlight TYPICAL APPLICATION VIN 12V ENA OB3375 1 LPWM 2 3 4 HPWM GATE VIN LPWM GND HPWM CS FAULT ZVS 8 7 6 5 GND ©On-Bright Electronics Confidential -1- Preliminary Datasheet OB_DOC_DS_337500 OB3375 High performance buck LED driver GENERAL INFORMATION Absolute Maximum Ratings Parameter VIN, LPWM, HPWM, FAULT, ZVS, GATE to GND CS to GND Operating Ambient Temp. TA Operating Junction Temp. TJ Min/Max Storage Temp. Tstg Lead Temp. (10 Sec) Recommended Operating Range Parameter Value Vin Voltage 9V to 30V LPWM Dimming Frequency 100Hz to 1KHz HPWM Dimming Frequency 10KHz to 50KHz Value -0.3V to 35V -0.3V to 7V -40℃ ~ 85℃ -40℃~ 150℃ -55℃ ~150℃ 260℃ Package Thermal Characteristics Parameter RθJA (℃/W) SOP8 150 Ordering Information Part Number Description OB3375CP SOP8, Halogen-free in tube OB3375CPA SOP8, Halogen-free in T&R Note: Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute maximum-rated conditions for extended periods may affect device reliability. Marking Information OB3375 High performance buck LED driver X X Package Halogen-free Package C:SOP8 X P:Halogen-free Packing Blank:Tube A: Taping YWWZZZ OB3375 Ps Y:Year Code WW:Week Code(01-52) ZZZ:Lot Code P:Halogen-free Package s:Internal Code(Optional) ©On-Bright Electronics Confidential -2- Preliminary Datasheet OB_DOC_DS_337500 OB3375 High performance buck LED driver Terminal Assignments for SOP8 Package Parts 1 8 GATE LPWM 2 7 GND HPWM 3 6 CS FAULT 4 5 ZVS VIN OB3375 Pin Num Pin Name I/O 1 VIN P 2 LPWM I/O LPWM signal input pin for PWM dimming control and enable pin for sleep mode control 3 HPWM I/O HPWM signal input pin for PWM to analog dimming control 4 FAULT I/O Fault signal for abnormal situation 5 ZVS I/O Quasi-Resonant signal 6 CS I/O Current sensing terminal. 7 GND P 8 GATE I/O ©On-Bright Electronics Description Power supply input. Power Ground. Gate driver output Confidential -3- Preliminary Datasheet OB_DOC_DS_337500 OB3375 High performance buck LED driver BLOCK DIAGRAM VIN UVLO Vref Reference OTP ZVS zvs detect LPWM _ + Logic Control GATE Driver GATE PWM + _ Soft start Vth_ocp CS sense High/low Frequency clamp FAULT Constant current regulation protection HPWM ©On-Bright Electronics CS Confidential -4- GND Preliminary Datasheet OB_DOC_DS_337500 OB3375 High performance buck LED driver ELECTRICAL CHARACTERISTICS VIN=12V,LPWM=5V, TA=25℃, if not otherwise noted. Parameter Symbol Conditions Current Consumption Input voltage range Vin Vin=12V,LPWM=5V Operating supply current 𝐼𝑉𝑉𝑉 no load LPWM low >50ms 𝐼𝑉𝑉𝑉_𝑠𝑠𝑠 Stand by current sleep mode VIN UVLO Vin under voltage lockout exit UVLO(OFF) (recovery) Vin under voltage lockout UVLO(ON) enter HPWM Section HPWM(high) High Level HPWM Logic input level HPWM(low) Low Level LPWM Control LPWM(high) High Level LPWM Input Threshold LPWM(low) Low Level Sleep mode time T_sleep Current Sense Input Section Time of leading edge blanking 𝑇𝑙𝑙𝑙 Threshold of over 𝑉𝑉ℎ𝑜𝑜𝑜 current protection QR Section Max frequency F max Max gate off time Toff max Max gate on time Ton max Error Amplifier Section Reference voltage of Vth_ea Error amplifier Protection Threshold of diode & 𝑉𝑉ℎ𝑐𝑐_ℎ𝑖𝑖ℎ1 Inductor short protection Threshold of CS pin open 𝑉𝑉ℎ𝑐𝑐_ℎ𝑖𝑖ℎ2 protection Temperature of thermal TOTP _ ON shutdown Temperature of thermal TOTP _ OFF recovery Gate Driver Output Gate rise time Trise 1nF load Gate fall time T fall 1nF load ©On-Bright Electronics Confidential -5- Min Typical Max 9 - 30 V - 1.1 1.3 mA - 20 30 uA 7 8 9 V 6.2 7.2 8.2 V 0.8 V V 2 2.5 1.3 V V ms 450 ns 40 250 350 0.8 V 200 20 20 230 25 25 260 30 30 0.245 0.25 0.255 - Units KHz us us V 1.5 V 2 V 150 ℃ 100 ℃ 150 ns 30 ns Preliminary Datasheet OB_DOC_DS_337500 OB3375 High performance buck LED driver CHARACTERIZATION PLOTS 50.00 𝐼_(𝑉𝑖𝑛_𝑠𝑡𝑏)(uA) vs Temperature 𝐼_(𝑉𝑖𝑛_𝑠𝑡𝑏)(uA) l𝐼_𝑉𝑖𝑛(mA) 2.000 𝐼_𝑉𝑖𝑛(mA) vs Temperature 40.00 1.600 30.00 1.200 20.00 0.800 10.00 0.400 0.00 0.000 -40 -10 20 50 80 -40 110 140 -10 UVLO_OFF(V) vs Temperature 80 110 140 UVLO_ON(V) vs Temperature 10.00 10.00 UVLO_ON(V) UVLO_OFF(V) 50 Temperature(℃) Temperature(℃) 9.20 8.40 7.60 6.80 6.00 9.00 8.00 7.00 6.00 5.00 -40 -10 20 50 80 110 140 -40 -10 Temperature(℃) 20 50 80 110 140 Temperature(℃) Toff_max(uS) vs Temperature Ton_max(uS) vs Temperature 50.00 Toff_max(uS) 50.00 Ton_max(uS) 20 40.00 30.00 20.00 10.00 40.00 30.00 20.00 10.00 0.00 0.00 -40 -10 20 50 80 -40 110 140 -10 20 50 80 110 140 Temperature(℃) Temperature(℃) Vth_ea(V) vs Temperature Vth_ea(mV) 0.300 0.250 0.200 0.150 0.100 -40 -10 20 50 80 110 140 Temperature(℃) ©On-Bright Electronics Confidential -6- Preliminary Datasheet OB_DOC_DS_337500 OB3375 High performance buck LED driver Function Description General Operation The OB3375 is a high efficiency LED driver designed for white LEDS and for large LCDS backlight. OB3375 is built-in a quasi-resonant control method buck DC/DC converter. The controller implements a peak current mode control scheme and an internal transconductance amplifier to accurately control the output current over a wide input and load conditions. The transconductance amplifier reference is set by internal reference voltage and the duty cycle at HPWM pin. Low frequency LPWM dimming input that can accept an external control signal with a duty ratio of 1%-100%. OB3375 offers comprehensive protection features to protect the system in various fault conditions such as Diode & Inductor short protection, CS open protection, MOS DS short protection, LED+/LEDshort protection, LED-/GND short circuit protection, over temperature protection (OTP). The cycle-by-cycle current limit function limits the maximum current flowing through the external MOSFET. The sensed error signal is amplified and compared to the CS pin sensing current signal to determine the on-time of the switching MOSFET. The error amplifier sources or sinks the current to the internal COMP to adjust the required inductor current as the load changes. The error amplifier reference is set by internal reference voltage and the duty cycle at HPWM pin. The average LED current is approximated by the following equation； 250 ∗ 𝐷𝐷𝐷𝐷𝐻𝐻𝐻𝐻 [𝑚𝑚] 𝐼𝐿𝐿𝐿 [𝑚𝑚] = 𝑅𝐶𝐶 [𝛺] At light loading, the OB3375 automatically add off time to improve efficiency and prevent overcharging the output capacitor. Dimming Control The LED brightness is controlled by the PWM signal at LPWM pin which has different duty cycle. OB3375 can accept an external PWM signal to LPWM pin in the range of 100Hz to 1 KHz with a swing voltage of 0V to a level greater than 2.5V. CS pin open Protection OB3375 shuts down the output if CS pin is floating. In case of CS pin floating, OB3375 will pull up CS pin to internal 5V voltage. If the CS voltage is greater than 2V (typical) at gate off time, the gate output will be latched off for the safe propose. This protection is latched and can be reset from VIN or LPWM. Startup OB3375 is enabled by applying a voltage of greater than approximately 2.5V to LPWM pin. An on-chip internal 3.8M ohm pull down resistor is inserted between LPWM pin and ground. When the first rising edge is applied to LPWM input, the OB3375 will power up immediately, and remains power up until the LPWM input is lower than 1.3V for 40mS (typical), at this time the chip will enter standby mode. At standby mode, the power of the OB3375 will be lower than 20uA (typical). When LPWM is active high, The OB3375 will check faults (UVLO, CS high, MOS ds short, LED+/LED- short, LED-short to GND, OCP), if there is no fault, then the boost converter will boost up the output with the internal soft start. LED+/LED- short & LED-/GND short protection When LED+/- short or LED- /GND short, IC can not detected demagnetization information ， OB3375 will continuously work at max_off state。After 60mS (typical), the gate output will be latched off for the safe propose. This protection is latched and can be reset from VIN or LPWM. UVLO An under-voltage lockout protection feature with a hysteresis of about 800mv is provided for VIN. When the voltage at this pin exceeds a threshold of approximately 8V (typ.), the IC starts normal operation. If the voltage at this pin drops below a threshold of approximately 7.2V (typ.) , the IC stops switching operation. The IC resumes switching operation when the voltage at pin VIN increases to a voltage above 8V (typical). Diode & Inductor Short Protection When the diode or the inductor shorts, the current of the power MOSFET increasing significantly. This state will cause the MOSFET permanent damage if the IC is continuously working. OB3375 will monitor the voltage on CS pin voltage cycle by cycle. If the voltage on CS pin is greater than 1.5V (typical) for continuous 16 cycles, the IC will latch shutdown the gate output to prevent the MOSFET from permanent damage. This protection is latched and can be reset from VIN or LPWM. LED Current Regulation The LED current is sensed by current sense resistors connected between pin CS and GND ©On-Bright Electronics Confidential -7- Preliminary Datasheet OB_DOC_DS_337500 OB3375 High performance buck LED driver MOS drain source Short Protection The OB3375 has power MOS source drain short protection, when power MOS source drain short, the OB3375 will monitor the CS voltage greater than 2V at gate off time or CS voltage greater than 0.25V continuous 50uS. The gate output will be latched off for the safe propose. This protection is latched and can be reset from VIN or LPWM. Thermal Shutdown The OB3375 includes a thermal protection circuit. When the junction temperature exceeds 150°C (typical), the controller and current sources shut down and do not restart until the junction temperature drops below 100°C (typical). logic level signal at FAULT pin. The output stage of the FAULT pin adopts an open-drain NMOS structure. When OB3375 is operating normally, the voltage at FAULT pin is pulled-high through external circuits. When there is any error condition occurs, the voltage at FAULT pin is pulled-low. The FAULT pin indicates the following seven conditions:  CS Open  Diode & Inductor Short  LED +/LED- short  Power MOS drain source short  LED-/ GND short  LED open Indication for FAULT Condition OB3375 builds an FAULT condition to output a ©On-Bright Electronics Confidential -8- Preliminary Datasheet OB_DOC_DS_337500 OB3375 High performance buck LED driver PACKAGE MECHANICAL DATA SOP8 Symbol A A1 A2 b c D E E1 e L θ ©On-Bright Electronics Dimensions In Millimeters Min Max 1.350 1.750 0.050 0.250 1.250 1.650 0.310 0.510 0.100 0.250 4.700 5.150 3.800 4.000 5.800 6.200 1.270 (BSC) 0.400 1.270 0º 8º Confidential -9- Dimensions In Inches Min Max 0.053 0.069 0.002 0.010 0.049 0.065 0.012 0.020 0.004 0.010 0.185 0.203 0.150 0.157 0.228 0.244 0.050 (BSC) 0.016 0.050 0º 8º Preliminary Datasheet OB_DOC_DS_337500 OB3375 High performance buck LED driver IMPORTANT NOTICE RIGHT TO MAKE CHANGES On-Bright Electronics Corp. reserves the right to make corrections, modifications, enhancements, improvements and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. WARRANTY INFORMATION On-Bright Electronics Corp. warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with its standard warranty. Testing and other quality control techniques are used to the extent it deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. On-Bright Electronics Corp. assumes no liability for application assistance or customer product design. Customers are responsible for their products and applications using On-Bright’s components, data sheet and application notes. To minimize the risks associated with customer products and applications, customers should provide adequate design and operating safeguards. LIFE SUPPORT On-Bright Electronics Corp.’s products are not designed to be used as components in devices intended to support or sustain human life. On-bright Electronics Corp. will not be held liable for any damages or claims resulting from the use of its products in medical applications. MILITARY On-Bright Electronics Corp.’s products are not designed for use in military applications. On-Bright Electronics Corp. will not be held liable for any damages or claims resulting from the use of its products in military applications. ©On-Bright Electronics Confidential - 10 - Preliminary Datasheet OB_DOC_DS_337500