WD3139F-6/TR

WD3139 WD3139 High Efficiency, 38V Step-Up White LED Driver Http//:www.sh-willsemi.com Descriptions The WD3139 is a constant current, high efficiency LED driver. Internal MOSFET can drive up to 10 white LEDs in series with 1.2A current limit and 38V OVP. A Pulse-Width-Modulation (PWM) signal can be applied to the EN pin for LED dimming. The device operates at 1MHz fixed switching frequency to reduce output ripple, TSOT-23-6L improve conversion efficiency, and allows using small external components. LX 1 The WD3139 is available in TSOT-23-6L Package. 6 VIN Standard product is Pb-free and Halogen-free. 5 OVP GND 2 Features  Input voltage range : 2.7~5.5V  Open LED Protection : 38V (Typ.)  Reference Voltage : 200mV (±5%)  Switching frequency : 1MHz (Typ.)  Efficiency : Up to 92%  Main switch current limit : 1.2A (Typ.)  PWM Dimming frequency : 5KHz to200KHz  PWM Dimming Duty Cycle : 0.5% ~ 100% FB 3 4 EN Pin configuration (Top view) 6 5 4 B39F ACYW Applications  Smart Phones  Tablets  Portable games 1 2 3 TSOT-23-6L B39F = Device code Y = Year code W = Week code Marking Order information Will Semiconductor Ltd. 1 Device Package Shipping WD3139F-6/TR TSOT-23-6L 3000/Reel&Tape May, 2015 - Rev. 1.1 WD3139 Typical applications L1 10μH~22μH VIN D1 WSB5543W VOUT CIN 1μF COUT 1μF/50V EN …… LX WD3139 VIN 10 LEDs OVP GND FB RSET Pin descriptions Symbol Pin No. Descriptions LX 1 Switch node GND 2 Ground FB 3 Feedback EN 4 Enable, Active High OVP 5 OVP Pin, Connect to VOUT VIN 6 Power Supply Block diagram OVP Current Sense OVP 38V LX PWM COMP Gate Driver PWM Logic VIN UVLO Chip Enable Bandgap Reference I SENSE 200mV EN PWM Dimming Logic Will Semiconductor Ltd. OSC 1.2A 1MHz FB Low-Pass Filter VREF Thermal Shutdown OCP EA VREF Soft Start GND 2 May, 2015 - Rev. 1.1 WD3139 Absolute maximum ratings Parameter Symbol Value Unit VIN pin voltage range VIN -0.3～6.5 V OVP pin voltage range VOVP -0.3～40 V EN pin voltage range - -0.3～VIN V LX pin voltage range (DC) - -0.3～40 V 0.5 W Power Dissipation – SOT-23-6L (Note 1) PD Power Dissipation – SOT-23-6L (Note 2) Junction to Ambient Thermal Resistance – SOT-23-6L (Note 1) Junction to Ambient Thermal Resistance – SOT-23-6L (Note 2) Junction temperature RθJA TJ Lead temperature(Soldering, 10s) TL Operation temperature Topr Storage temperature Tstg 0.3 W 250 o 416 o C/W C/W 150 o 260 o -40 ~ 85 o -55 ~ 150 o C C C C These are stress ratings only. Stresses exceeding the range specified under “Absolute Maximum Ratings” may cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability. Note 1: Surface mounted on FR-4 Board using 1 square inch pad size, dual side, 1oz copper Note 2: Surface mounted on FR-4 board using minimum pad size, 1oz copper Will Semiconductor Ltd. 3 May, 2015 - Rev. 1.1 WD3139 Electronics Characteristics (Ta=25oC, VIN=3.6V, VEN=VIN, CIN=COUT=1uF, unless otherwise noted) Parameter Symbol Operation Voltage Range VIN Under Voltage Lockout VUVLO UVLO Hysteresis VUVLO-HYS Over-Voltage Threshold VOVP Quiescent Current IQ Supply Current Test Condition VIN Rising Unit Min Typ Max 2.7 -- 5.5 V 1.8 2.3 2.5 V 0.15 V 38 40 V No Switching 0.2 1 mA IS Switching 1.2 3 mA Shutdown Current ISD VEN < 0.4V 1 μA Operation Frequency fOSC 0.8 1 1.2 MHz Maximum Duty Cycle DMAX 91 93 PWM Dimming Clock Rate 36 s Recommended PWM Dimming Duty Cycle Feedback Reference VREF On Resistance RON Current Limit ILIM EN Threshold Voltage 100% Full Scale % 5 200 KHz 0.5 100 % 190 200 210 mV 1% Dimming Duty 2 ILX=100mA 0.45 Ω 1.2 A VENL 0.4 VENH 1.5 V V EN Pull-down Resistance REN 1 MΩ Thermal Shutdown Temperature TSD 160 °C TSD Hysteresis TSD-HYS 30 °C Shutdown Delay tSHDN 1 ms Will Semiconductor Ltd. 4 May, 2015 - Rev. 1.1 WD3139 o 100 100 90 90 80 70 L=10uH 10S LED VIN=3.2V VIN=3.6V 60 50 Efficiency (%) Efficiency (%) Typical Characteristics (Ta=25 C, unless otherwise noted) VIN=5.0V 4 6 8 10 12 14 16 18 L=22uH 10S LED VIN=3.2V 70 VIN=3.6V 60 VIN=4.2V 2 80 50 20 VIN=4.2V VIN=5.0V 2 4 6 100 100 90 90 80 50 L=10uH 6S2P LED VIN=3.2V VIN=3.6V VIN=5.0V 8 12 16 20 24 28 32 36 70 50 40 VIN=4.2V VIN=5.0V 4 8 12 20 24 28 20.5 1.1 20.0 10S LED VIN=3.2V VIN=3.6V 40 VIN=3.2V 0.9 60 0.8 80 o Temperature ( C) LED Current vs. Temperature Will Semiconductor Ltd. 40 VIN=3.6V VIN=4.2V VIN=5.0V 20 36 1.0 VIN=4.2V 0 32 Efficiency vs. Output Current Frequency (MHz) LED Current (mA) 16 Output Current (mA) 1.2 -20 20 VIN=3.6V 21.0 -40 18 L=22uH 6S2P LED VIN=3.2V Efficiency vs. Output Current 19.0 16 80 Output Current (mA) 19.5 14 60 VIN=4.2V 4 12 Efficiency vs. Output Current Efficiency (%) Efficiency (%) Efficiency vs. Output Current 60 10 Output Current (mA) Output Current (mA) 70 8 VIN=5.0V -40 -20 0 20 40 o Temperature ( C) 60 80 Frequency vs. Temperature 5 May, 2015 - Rev. 1.1 WD3139 2.5 2.4 39 UVLO (V) OVP Threshold Voltage (V) 40 38 VIN=3.2V 37 VIN=3.6V VIN=5.0V -40 -20 0 20 40 60 2.2 2.1 VIN=4.2V 36 2.3 Rising Falling 2.0 80 -25 0 o 1.0 1.0 Enable Threshold(V) Enable Threshold (V) 1.1 0.9 0.8 0.7 Enable Disable 3.5 4.0 4.5 0.9 0.8 0.7 V =3.6V IN 0.6 5.0 Enable Disable -40 -20 20 40 60 80 Temperature ( C) Enable Threshold vs. VIN Enable Threshold vs. Temperature 2.0 Supply Current (mA) 0.24 Quiescent Current (mA) 0 o Supply Voltage (V) 0.22 0.20 0.18 2.5 75 UVLO vs. Temperature 1.1 3.0 50 Temperature ( C) OVP Threshold vs. Temperature 0.6 2.5 25 o Temperature ( C) 3.0 3.5 4.0 Supply Voltage (V) 4.5 1.2 0.8 2.5 5.0 Quiescent Current vs. VIN Will Semiconductor Ltd. 1.6 3.0 3.5 4.0 Supply Voltage (V) 4.5 Supply Current vs. VIN 6 May, 2015 - Rev. 1.1 5.0 WD3139 0.30 2.0 20 Samples 20 Samples 1.6 LED Current (mA) LED Current (mA) 0.25 1.2 0.8 0.4 0.0 1 2 3 4 5 6 7 8 Dimming Duty Cycle (%) 9 0.15 0.10 0.05 10S LED, 25KHz VIN=3.6V 0 0.20 0.00 0.0 10 LED Current Dimming Linearity 1% Dimming Percentage of Samples (%) Percentage of Samples (%) 0.4 0.6 0.8 Dimming Duty Cycle (%) 1.0 35 100 Samples 1 Production Lot 25 20 15 10 5 0 0.2 LED Current Dimming Linearity 35 30 10S LED, 25KHz VIN=3.6V 0.8 0.9 1.0 1.1 3% Dimming 100 Samples 1 Production Lot 25 20 15 10 5 0 0.85 1.2 0.90 0.95 1.00 1.05 1.10 Normalized Feedback Voltage Normalized Feedback Voltage Distribution of VFB Dimming at 1% Distribution of VFB Dimming at 3% Start-Up from EN Will Semiconductor Ltd. 30 Shut-Down from EN 7 May, 2015 - Rev. 1.1 1.15 WD3139 Start-Up from VIN Shut-Down from VIN Start-Up with LED Open Shut-Down with LED Open Operation Waveforms PWM Dimming Waveforms Will Semiconductor Ltd. 8 May, 2015 - Rev. 1.1 WD3139 Operation Information Normal Operation Once output voltage goes over the OVP threshold 38V, LX pin stops switching and the N-MOSFET will The WD3139 is a high efficiency, high output be turned off. Then, the output voltage will be voltage boost converter. The device is ideal for clamped to be near OVP. Until the OVP eliminate driving white LED. The LED connection provides the N-MOSFET will be turned on. even illumination by sourcing the same output current through all LEDs. The device integrates UVLO Protection 38V/1.2A switch FET and operates in pulse width To avoid malfunction of the WD3139 at low input modulation (PWM) with 1MHz fixed switching voltages, an under voltage lockout is included that frequency. The beginning of each cycle turns on the disables the device, until the input voltage exceeds Power MOSFET. A slope compensation ramp is 2.3V (Typ.). added to the current sense amplifier and the result is fed into the positive input of the comparator Shutdown Mode (COMP). When this voltage goes above the output Drive EN to GND to place the WD3139 in shutdown voltage of the error amplifier (EA), the Power mode. In shutdown mode, the reference, control MOSFET is turned off. The FB voltage can be circuit, and the main switch turn off. Input current regulated to the reference voltage of bandgap with falls to smaller than 1μA during shutdown mode. EA block. The feedback loop regulates the FB pin to a low reference voltage (200mV typical), reducing the power dissipation in the current sense resistor. Over-Temperature-Protection (OTP) As soon as the junction temperature (T J) exceeds o Soft-Start 160 C (Typ.), the WD3139 goes into thermal shutdown. In this mode, the main N-MOSFET is The WD3139 Build-in Soft-Start function limits turned off until temperature falls below typically inrush current while the device turn-on. 130 C. Then the device starts switching again. o Cycle-by-Cycle Current Limit The WD3139 uses a cycle-by-cycle current limit circuitry to limit the inductor peak current in the event of an overload condition. The current flow through inductor in charging phase is detected by a current sensing circuit. As the value comes across the current limiting threshold the N- MOSFET turns off, so that the inductor will be forced to leave charging stage and enter in discharging stage. Therefore, the inductor current will not increase over the current limiting threshold. Over-Voltage-Protection (OVP) The Over Voltage Protection is detected by OVP block, prevents IC damage as the result of white LED disconnection. Will Semiconductor Ltd. 9 May, 2015 - Rev. 1.1 WD3139 Application Information External component selection for the application circuit depends on the load current requirements. Certain trade-offs between different performance parameters can also be made. LED Current Setting The loop of Boost structure will keep the FB pin voltage equal to the reference voltage VREF. Therefore, when RSET connects FB pin and GND, the current flows from VOUT through LED and RSET to Figure 1 GND will be decided by the current on RSET, which is equal to following equation: ILED = VFB 200mV = RSET RSET Where ILED = output current of LEDs VFB = regulated voltage of FB RSET = current sense resistor The output current tolerance depends on the FB accuracy and the current sensor resistor accuracy. Therefore, although a PWM signal is applied for dimming, but only the WLED DC current is modulated. This help to eliminate the audible noise which often occurs when the LED current is pulsed in replica of the frequency and the duty cycle of PWM control. The minimum dimming frequency is limited by EN shutdown delay time. For optimum performance, recommend to select PWM dimming frequency in the range of 5kHz~200kHz. And the recommended minimum PWM Duty Cycle is 0.5% for stable LED driving and no blind dimming. Dimming Control For the brightness dimming control of the WD3139, the IC provides typically 200mV feedback voltage when the EN pin is pulled constantly high. However, The EN shutdown delay time is set to 1ms. This means the IC needs to be shutdown by pulling the EN low for 1ms. EN pin allows a PWM signal to reduce this regulation voltage by changing the PWM duty cycle to achieve LED brightness dimming control. As shown in Figure 1, the duty cycle of the PWM signal is used to chop the internal 200mV reference voltage. An internal low pass filter is used to filter the pulse signal. And then the reference voltage can be made by connecting the output of the filter to the error amplifier for the FB pin voltage regulation. Will Semiconductor Ltd. 10 May, 2015 - Rev. 1.1 WD3139 Applications for Driving 3S9P LEDs inductor for 10 series WLEDs applications is from 10μH to 22μH. A 22μH inductor with Low DCR The WD3139 can drive different WLEDs topology. optimized the efficiency for most application while For example, the Figure 2 shows the 6S2P WLEDs maintaining low inductor peak to peak ripple. as output load. The total WLEDs current can be set by the RSET which is equal to following equation. Input Capacitor Selection With VIN>3.4V, The WD3139 could drive maximum Connect the input capacitance from VIN to the 3S9P with total 27 LEDs. reference ground plane. Input capacitance reduces ITotal = VIN L1 10μH~22μH the ac voltage ripple on the input rail by providing a VREF RSET D1 WSB5543W CIN 1μF low-impedance path for the switching current of the boost converter. The capacitor in the range of 1μF to 10μF / X7R or X5R is recommended for input VOUT COUT 1μF/50V EN GND Output Capacitor Selection The output capacitor is mainly selected to meet the LX WD3139 VIN side. 6S2P LEDs OVP requirements for the output ripple and loop stability. This ripple voltage is related to the capacitor’s capacitance and its equivalent series resistance (ESR). The recommended minimum capacitor on FB RSET Output is 1uF/50V, X5R or X7R ceramic capacitor. Diode Selection Figure 2 The rectifier diode supplies current path to the inductor when the internal MOSFET is off. Use a schottky with low forward voltage to reduce losses. Boost Inductor Selection The selection of the inductor affects steady state operation as well as transient behavior and loop stability. Inductor values can have ±20% tolerance with no current bias. When the inductor current approaches saturation level, its inductance can decrease 20% to 35% from the 0A value depending on how the inductor vendor defines saturation current. Using an inductor with a smaller inductance value forces discontinuous PWM when the inductor current ramps down to zero before the end of each The diode should be rated for a reverse blocking voltage greater than the output voltage used. 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. Diode the following requirements: ● Low forward voltage ● High switching speed : 50ns max. ● Reverse voltage : VOUT + VF or more ● Rated current : IPK or more switching cycle. This reduces the boost converter’s maximum output current, causes large input voltage ripple and reduces efficiency. Large inductance value provides much more output current and higher conversion efficiency. The inductor should have low core loss at 1MHz and low DCR for better efficiency. For these reasons, the recommended value of Will Semiconductor Ltd. 11 May, 2015 - Rev. 1.1 WD3139 PCB Layout Considerations A good circuit board layout aids in extracting the most performance from the WD3139. Poor circuit layout degrades electromagnetic the output interference ripple (EMI) or and the electro- magnetic compatibility (EMC) performance. The evaluation board layout is optimized for the WD3139. Use this layout for best performance. If this layout needs changing, use the following guidelines: 1. Use separate analog and power ground planes. Connect the sensitive analog circuitry (such as voltage divider components) to analog ground; Top connect the power components (such as input and output bypass capacitors) to power ground. Connect the two ground planes together near the load to reduce the effects of voltage dropped on circuit board traces. Locate CIN as close to the VIN pin as possible, and use separate input bypass capacitors for the analog. 2. Route the high current path from CIN, through L to the LX and GND pins as short as possible. 3. Keep high current traces as short and as wide Bottom as possible. 4. WD3139 PCB Suggest Layout (Demo) The output filter of the boost converter is also critical for layout. The Diode and Output capacitors should be placed to minimize the area of current loop through Output –GND–LX. 5. Avoid routing high impedance traces, such as Output, near the high current traces and components or near the Diode node. 6. If high impedance traces are routed near high current and/or the LX node, place a ground plane shield between the traces. 7. Place the RSET resistor as close as possible to FB pin, for the FB is a high impedance input pin which is susceptible to noise. Will Semiconductor Ltd. 12 May, 2015 - Rev. 1.1 WD3139 Package outline dimensions TSOT-23-6L Symbol Dimensions in millimeter Min. Typ. Max. A - - 0.900 A1 0.000 - 0.100 A2 0.700 - 0.800 b 0.350 - 0.500 c 0.080 - 0.200 D 2.820 2.900 3.020 E1 1.600 1.650 1.700 E 2.650 2.800 2.950 e 0.950 (BSC) e1 1.900 (BSC) L 0.300 - 0.600 θ 0° - 8° Will Semiconductor Ltd. 13 May, 2015 - Rev. 1.1