MP3376AGR-XXXX-Z

MP3376A 8-Channel, Synchronous, Boost, WLED Driver with I2C Interface The Future of Analog IC Technology DESCRIPTION FEATURES The MP3376A is a synchronous boost converter with eight current channels designed to drive WLED arrays for LCD panels in tablets and notebook backlighting applications.  8 Channels with Max 50mA/Channel  Synchronous Converter with LS-FET/HSFET 160m/260mΩ On Resistance  3V to 30V Input Voltage Range  Up to 37.5V Output Voltage  520mV LED Regulation Voltage at 20mA  Max 2.5% Current Matching  350kHz / 500kHz / 650kHz / 800kHz / 950kHz / 1.2MHz / 1.8MHz / 2.4MHz Selectable Switching Frequency  A0, A1 Pins for Four I2C Addresses  0mA to 50mA Full-Scale LED Current, 8-Bit, 0.196mA/Step  Selectable Sync or Non-Sync Mode  Multi-Dimming Operation Mode Including: o Analog Dimming through External PWM Input, 10-Bit Resolution o Analog Dimming through I2C Interface, 10-Bit Resolution o Mixed Dimming Mode through External PWM Input with 6.25% / 12.5% / 25% / 50% Transfer Point o Mixed Dimming Mode through I2C interface with 6.25% / 12.5% / 25% / 50% Transfer Point  Customizable Default Register Values  Linear Smooth Dimming with 2 / 4 / 8 / 16 / 32 / 64 / 128µs Step-Slope Set  Unused LED String Auto-Disable during Start-Up  LED Short/Open, OTP, OCP, Inductor or Diode Short Protection o 2.5 / 5 / 7.5 / 10V LED Short Threshold o 24 / 31 / 37.5V OVP Threshold o 1.8 / 2.5A Current Limit  Available in a QFN-24 (4mmx4mm) Package The MP3376A uses peak-current-mode and pulse-width modulation (PWM) control to maintain boost converter regulation. The MP3376A employs a standard I2C digital interface to set the operation mode, switching frequency, full-scale current for each channel, sync or non-sync mode, dimming mode and duty, and various protection thresholds. The MP3376A features high efficiency due to low-headroom voltage for LED regulation and a small on resistance of the switching MOSFET. The synchronous rectifier saves PCB size and total BOM cost. The MP3376A is available in a QFN-24 (4mmx4mm) package. APPLICATIONS  Tablets/Notebooks  Automotive Displays All MPS parts are lead-free, halogen-free, and adhere to the RoHS directive. For MPS green status, please visit the MPS website under Quality Assurance. “MPS” and “The Future of Analog IC Technology” are registered trademarks of Monolithic Power Systems, Inc. MP3376A Rev.1.0 8/24/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 1 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C TYPICAL APPLICATION MP3376A Rev.1.0 8/24/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 2 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C ORDERING INFORMATION Part Number* MP3376AGR-xxxx** Package QFN-24 (4mmx4mm) Top Marking See Below * For Tape & Reel, add suffix –Z (e.g. MP3376AGR-XXXX-Z) ** “XXXX” is the register setting option. The factory default is “0000.” This content can be viewed in Table 1 through Table 6. For custom options, please contact an MPS FAE to obtain a “XXXX” value. TOP MARKING MPS: MPS prefix Y: Year code WW: Week code M3376A: Part number LLLLLL: Lot number PACKAGE REFERENCE QFN-24 (4mmx4mm) MP3376A Rev.1.0 8/24/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 3 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C ABSOLUTE MAXIMUM RATINGS (1) VSW, VOUT.......................................-0.3V to +40V VFT ................................................. VIN - 6V to VIN VLEDX .............................................-0.3V to +40V VBST ........................................ -0.3V to VSW + 6V VIN .................................................-0.3V to +32V All other pins ................................-0.3V to +6.5V Junction temperature ................................150°C Lead temperature .....................................260°C (2) Continuous power dissipation TA = 25°C QFN-24 (4mmx4mm) ................................. 2.7W Recommended Operating Conditions (3) Supply voltage (VIN) ........................... 3V to 30V Operating junction temp. (TJ) ... -40°C to +125°C MP3376A Rev.1.0 8/24/2017 Thermal Resistance (4) θJA θJC QFN-24 (4mmx4mm) ............. 46 ....... 10 ... °C/W 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 produces an excessive die temperature, causing the regulator to 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 operating conditions. 4) Measured on JESD51-7, 4-layer PCB. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 4 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C ELECTRICAL CHARACTERISTICS VIN = 3.7V, VEN = 2V, TA = 25°C, unless otherwise noted. Parameter Symbol Condition Operating input voltage Supply current (quiescent) Supply current (shutdown) Input UVLO threshold VIN IQ IST VIN_UVLO Min 2.7 VCC V 200 mV 1 VEN = 2V, 6V < VIN < 30V, 0 < IVCC < 10mA 4.4 1.2 EN off threshold VEN_OFF VEN falling EN pull-down resistor REN A0, A1 low threshold VA_Lo VA falling A0, A1 high threshold VA_Hi VA rising A0, A1 pull-up resistor Step-Up Converter Low-side MOSFET on resistance High-side MOSFET on resistance RP RDS_LS RDS_HS SW leakage current ISW_LK SW current limit 4.9 5.4 V V 0.4 500 V kΩ 0.4 1.2 V V 500 kΩ VIN = 6V 160 mΩ VIN = 6V 260 mΩ A DMAX V mA μA 2.5 VEN rising Maximum duty cycle 30 Rising edge VEN_ON FSW Units 5.4 EN on threshold Switching frequency Max VIN = VEN = 3.7V, no switching VEN = 0V, VIN = 3.7V Input UVLO hysteresis LDO output voltage Typ VSW = 40V FS2:0 bits = 011b FS2:0 bits = 010b Sync mode, FSW = 800kHz Non-sync mode, FSW = 800kHz ISW_LIMIT Duty = 90%, ILIM bit = 1b PWM input low threshold VPWM_LO VPWM falling PWM input high threshold VPWM_HI VPWM rising 1 μA 720 585 90 93 800 650 94 95 880 715 kHz kHz % % 2 2.5 3 A 0.4 V Current Dimming PWM pull-down resistor Mix dimming transfer point Current up/down slope PWM dimming frequency set by I2C LED Current Regulator LEDX regulation voltage Current matching (5) Full-scale current MP3376A Rev.1.0 8/24/2017 1.2 RPWM V TSTEP DIMT1:0 bits = 10b TSLP2:0 bits = 011b 500 25 16 kΩ % μs FPWM FPWM3:0 bits = 1010b 22 kHz VHD ILED = 20mA ILED = 20mA ISET7:0 bits = FFh ISET7:0 bits = 66h 440 520 49 19.6 50 20 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 600 2.5 51 20.4 mV % mA mA 5 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C ELECTRICAL CHARACTERISTICS (continued) VIN = 3.7V, VEN = 2V, TA = 25°C, unless otherwise noted. Parameter Protection Over-voltage protection threshold Symbol Condition OVP UVLO threshold VOVP_UV LEDX over-voltage threshold VLEDX_OV LEDS1:0 bits = 10b VOVP LEDX over-voltage fault timer LEDX UVLO threshold Typ Max Units 36 37.5 39 V Step-up converter fails FSW = 1.2MHz 1.5 VLEDX_UV Thermal shutdown threshold TST FT pull-down current FT voltage w/ respect to VIN I2C Interface Input logic low Input logic high Output logic low SCL clock frequency Set-up time for repeated start condition Hold time for repeated start condition Low time for SCLH clock High time for SCLH clock Data set-up time Data hold time IFT VFT-IN Rise time of SCLH clock Rise time of SCLH clock after repeated start and acknowledge bit Fall time of SCLH clock Rise time of SDAH data Fall time of SDAH data Set-up time for stop condition Capacitive load for SDAH line and SCLH line Capacitive load for SDAH+SDA line and SCLH+SCL line Rising edge, OVP1:0 bits = 10b Min VIL VIH VOL fSCL Rising edge Hysteresis 50 VIN = 12V, VFT-IN = VIN - VFT 1.2 V 7.5 V 1.8 2 ms 100 mV 150 20 60 6 °C °C μA V 70 0.4 1.3 ILOAD = 3mA 0.4 1200 V V V kHz tSU,STA 160 ns tHD,STA 160 ns tHIGH tLOW tSU,DAT tHD,DAT 160 60 10 0 (6) 70 ns ns ns ns tR,SCL 10 40 ns tR,SCL1 10 80 ns tF,SCL tR,SDA tF,SDA tSU,STO 10 10 10 160 40 80 80 ns ns ns ns CB (7) 100 pF CB 400 pF NOTES: 5) Matching is defined as the difference of the maximum to minimum current divided by 2 times the average current. 6) A device must provide a data hold time internally to bridge the undefined part between VIL and VIH of the falling edge of the SCLH signal. An input circuit with a threshold as low as possible for the falling edge of SCLH signal minimizes the hold time. 7) For the bus line load CB between 100pF and 400pF the timing parameters must be increased linearly. MP3376A Rev.1.0 8/24/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 6 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C I2C Compatible Interface Timing Diagram MP3376A Rev.1.0 www.MonolithicPower.com 8/24/2017 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 7 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C TYPICAL PERFORMANCE CHARACTERISTICS VIN = 7V, 8 LEDs in series, 8 strings, 20mA/string, L = 4.7µH, TA = 25°C, unless otherwise noted. MP3376A Rev.1.0 8/24/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 8 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C PIN FUNCTIONS Pin # Name 1 VCC 2 EN 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17, 19, 22 18 20 SDA SCL PWM A0 A1 LED8 LED7 LED6 LED5 LED4 LED3 LED2 LED1 PGND NC OUT SW 21 BST 23 FT 24 VIN EP MP3376A Rev.1.0 8/24/2017 Description 4.9V LDO output. VCC provides power for the internal logic and gate driver. Place a ceramic capacitor as close to VCC as possible to reduce noise. IC enable. Pull EN high to enable the IC; pull EN low to make the IC enter shutdown mode. I2C interface data input. I2C interface clock input. PWM signal input. Connect PWM to GND if not used. IC Select. A0 is pulled high internally. IC Select. A1 is pulled high internally. LED current source 8 output. If LED8 is unused, tie it to GND. LED current source 7 output. If LED7 is unused, tie it to GND. LED current source 6 output. If LED6 is unused, tie it to GND. LED current source 5 output. If LED5 is unused, tie it to GND. LED current source 4 output. If LED4 is unused, tie it to GND. LED current source 3 output. If LED3 is unused, tie it to GND. LED current source 2 output. If LED2 is unused, tie it to GND. LED current source 1 output. If LED1 is unused, tie it to GND. Power ground. No connection. Synchronous boost output. Switching node. Bootstrap capacitor node for the high-side MOSFET. Connect a 100nF ceramic capacitor and a 47Ω resistor in series between BST and SW for synchronous mode. Input and output disconnection PMOS gate driver. If there is no fault, FT is pulled low to turn on the external PMOS. Float FT and connect the inductor to VIN directly if the disconnection function is not needed. IC input power. Place a ceramic capacitor as close to VIN as possible to reduce noise. Exposed pad. Connect the EP to GND. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 9 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C BLOCK DIAGRAM IN FT BST OUT SW FT Management LEDOV OVP Protection VIN-6V VCC Regulator EN Bandgap & Logic - Logical Control + PWM Comparator Current Limit Protection OSC + PGND - LED Short Protection + Vref + EA LEDSV Max DAC LED1 - Digital Control Feedback Voltage Control + PWM Min LED2 OP AMP LED3 LED4 Current Control SCL SDA A0 LED5 LED6 I2C Control LEDSV LEDOV LED7 LED8 A1 Figure 1: Functional Block Diagram MP3376A Rev.1.0 8/24/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 10 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C OPERATION The MP3376A is a programmable, constantfrequency, peak-current-mode, step-up converter with up to eight channels of regulated current sources to drive an array of white LEDs. The MP3376A provides a fully integrated solution that saves PCB size and total solution cost. For ease of use, an I2C interface is also integrated into the IC. Internal 4.9V Regulator The MP3376A includes an internal linear regulator (VCC). When VIN is greater than 6V, this regulator outputs a 4.9V power supply to the internal MOSFET gate driver and internal control circuitry. VCC drops to 0V when the chip shuts down. The MP3376A is disabled until VCC exceeds the UVLO threshold. Internal Clock The MP3376A has a fixed 10MHz clock for the internal timer and counter to achieve a high dimming resolution. Boost Converter Switching Frequency The boost converter switching frequency can be set by the FS2:0 bits of register 01h. It can be set to 350kHz, 500kHz, 650kHz, 800kHz, 950kHz, 1.2MHz, 1.8MHz, or 2.4MHz. System Start-Up When enabled, the MP3376A checks the topology connection. First, the IC draws current from FT to turn on the input disconnect PMOS if this MOSFET is being used. Second, after a 500µs delay, the IC monitors the OUT voltage (VOUT) to determine if the output is shorted to GND. If the output voltage is less than 1.2V, the IC is disabled. Lastly, the MP3376A continues to check other safety limits, such as LED open and over-voltage protection (OVP). If all protection tests pass, the IC begins boosting the step-up converter with an internal soft start. The MP3376A can start up properly regardless of the order in which VIN, PWM, and EN turn on. To achieve a quick response, the recommended power-on sequence is from VIN power on  EN on (wait for 2ms)  send I2C data  PWM dimming signal (see Figure 2). When dimming is done just by the I2C interface, the PWM signal can be ignored. MP3376A Rev.1.0 8/24/2017 Figure 2: Recommended Power-On Timing Step-Up Converter The MP3376A uses peak-current-mode control to regulate the output voltage. At the beginning of each switching cycle, the internal clock turns on the low-side N-channel MOSFET. In normal operation, the minimum turn-on time is around 100ns. A stabilizing ramp added to the output of the current sense amplifier prevents subharmonic oscillations for duty cycles greater than 50%. This result is fed into the PWM comparator. When the summed voltage reaches the output voltage of the error amplifier, the low-side MOSFET turns off. The output voltage of the error amplifier is an amplified signal of the difference between the reference voltage and the feedback voltage. The converter chooses the lowest active LEDX voltage automatically as the feedback voltage to regulate an output voltage high enough and power all of the LED arrays. If the feedback voltage drops below the reference, the output of the error amplifier increases. This results in increased current flowing through the MOSFET and increased power delivered to the output. This forms a closed loop that regulates the output voltage. Pulse-Skipping Mode Under light-load operation, especially in the case of VOUT ≈ VIN, the converter runs in pulseskipping mode, where the MOSFET turns on for a minimum on time. In this mode, the device keeps the power switch off for several switching cycles to prevent the output voltage from rising above the regulated voltage. When the chip stops switching, the output capacitor discharges to the power LED string. The device begins switching until the output voltage needs to be boosted again. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 11 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C Full-Scale Current Setting LED full-scale current can be set by the register ISET7:0 bits from 0-50mA with 0.196mA per step. Dimming Control The MP3376A can provide flexible dimming methods based on the dimming mode setting shown below, including analog dimming mode and mix dimming mode (see Figure 3 and Figure 4). Each mode can control the brightness by the PWM input signal or I2C interface. Figure 3: Analog Dimming Mode Flow Chart Figure 4: Mix Dimming Mode Flow Chart MP3376A Rev.1.0 8/24/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 12 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C The MP3376A has four types of dimming modes total. 1. Analog Dimming Mode from PWM Input MOD2:0 bits = 000b. In analog dimming mode, the LED current amplitude is dependent on the duty cycle of the PWM input signal. Note that the current amplitude can be changed by the register ADIM9:0 10-bit value (see Figure 5). IC works in PWM dimming mode, and the PWM LED current frequency is set by the register FPWM3:0 bits. The PWM LED current duty is extended according to the transfer point selected. For example, if the transfer point is 25%, then the PWM LED current duty = PWM input duty x 1/(25%). The PWM LED current amplitude is fixed to the value at the transfer point set by DIMT1:0. Note that the current amplitude can be changed by the register ADIM9:0 10-bit value (see Figure 7). Figure 5: Analog Dimming from PWM Input 2. Analog Dimming Mode from I2C Interface MOD2:0 bits = 001b. In analog dimming mode, the LED current amplitude is set by the internal register PWM13:0 bits. Note that the current amplitude can be changed by the register ADIM9:0 10-bit value (see Figure 6). Figure 6: Analog Dimming from I2C Interface 3. Mix Dimming Mode from PWM Input MOD2:0 bits = 100b. In mix dimming mode, if the duty cycle from PWM is larger than the threshold set by the register DIMT1:0 bits, the IC works in analog dimming mode. The LED current amplitude follows the input duty. If the duty cycle from the PWM input is lower than the threshold set by the register DIMT1:0 bits, the MP3376A Rev.1.0 8/24/2017 Figure 7: Mix Dimming from PWM Input 4. Mix Dimming Mode from I2C Interface MOD2:0 bits = 101b. In mix dimming mode, if the duty cycle from the internal register PWM13:0 bits is larger than the threshold set by register DIMT1:0 bits, the IC works in analog dimming mode. The LED current amplitude follows the register PWM13:0 bits. If the duty cycle from the register PWM13:0 bits is lower than the threshold set by register DIMT1:0 bits, the IC works in PWM dimming mode, and the PWM frequency is set by the register FPWM3:0 bits. The PWM LED current duty is extended according to the transfer point selected. For example, if the transfer point is 25%, then the PWM LED current duty = duty set by PWM13:0 bits x 1/(25%). The PWM LED current amplitude is fixed to the value at the transfer point duty set by DIMT1:0. Note that the current amplitude can be changed by the register ADIM9:0 10-bit value (see Figure 8). www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 13 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C In some cases, such as extremely high switching frequency and high output power applications, it is recommended to use an external rectifier for better thermal and efficiency. To disable the internal synchronous rectifier, set the register SYNC bit to 0. Figure 8: Mix Dimming from I2C Interface Linear Dimming for Fade In/Out The MP3376A provides linear current rise up or down. The LED current ramps up or down linearly. The current ramp-up or ramp-down slope can be set by the register TSLP2:0 bits from 2µs to 128µs (0.049mA for each step). Deep Dimming Ratio To provide enough output energy for the LED load when the PWM LED current duty is very small, the MP3376A provides at least four switching cycles to guarantee sufficient output voltage before the next PWM LED current on duty cycle. This way, the MP3376A can achieve a very wide dimming ratio range in PWM dimming mode. The dimming ratio is dependent on the LED current dimming frequency and LED current source turn-on/-off time. The lower the PWM dimming frequency, the deeper the dimming ratio. For MP3376A it is recommended that the minimum on time of the LED string is higher than 1.5µs to achieve good dimming. The dimming ratio can reach to 100:1 at 22kHz in mix dimming mode. Unused LED Channel Setting The MP3376A can detect an unused LED string automatically and remove it from the control loop during start-up by either connecting the unused LEDX pin to GND or by setting the corresponding register CHEN7:0 bits to 0. Synchronous Rectifier To save cost and reduce PCB size, the MP3376A works in synchronous rectifier mode by default. A 100nF ceramic capacitor and a 47Ω resistor in series between BST and SW is the best BST supply choice for the synchronous converter. MP3376A Rev.1.0 8/24/2017 Open-String Protection Open-string protection is achieved by detecting the voltage of OUT and LED1-8. During operation, if one string is open, the respective LEDX pin voltage is pulled low to ground, and the IC continues charging the output voltage until it reaches the OVP threshold (set by OVP1:0 bits). If the OVP point has been triggered, the chip stops switching and marks off the fault string that has an LEDX pin voltage lower than 100mV. Once marked, the remaining LED strings force the output voltage back to normal regulation. The string with the largest voltage drop determines the output regulation value. Short-String Protection The MP3376A monitors the LEDX pin voltages to determine if a short-string fault has occurred. If one or more strings are shorted, the respective LEDX pins tolerate high voltage stress. If an LEDX pin voltage is higher than the protection threshold (programmable by LEDS1:0 bits), an internal counter is started. If this fault condition lasts for 1.8ms (fSW = 1.2MHz), the fault string is marked off and disabled. Once a string is marked off, it is disconnected from the output voltage loop until the part restarts. If all strings are shorted, the MP3376A shuts down the step-up converter until the power is restarted (VIN supply switches on from off) or EN is toggled (EN switches on from off). Cycle-by-Cycle Current Limit To prevent the external components from exceeding the current stress rating, the IC uses a cycle-by-cycle current-limit protection. The limit value can be selected by the register ILIM bit. When the current exceeds the current limit value, the IC stops switching until the next clock cycle begins. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 14 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C Latch-Off Current Limit Protection To avoid device damage caused by a large current rating (such as inductor or diode short to GND), the MP3376A uses a latch-off currentlimit protection when the current flowing through the low-side MOSFET reaches the threshold (3.5A) in around 200ns and lasts for five switching cycles. The OTPEN bit resets to 0 after 400ms of burning time. The timer (05H-D7:5) counts the number of times the register has been burnt successfully. Thermal Protection To prevent the IC from operating at exceedingly high temperatures, thermal shutdown is implemented by detecting the silicon die temperature. When the die temperature exceeds the upper threshold (TST), the IC shuts down and resumes normal operation when the die temperature drops below the lower threshold. Typically, the hysteresis value is 20°C. I2C Interface Register Description Please read/write the register after EN is ready for longer than 2ms. One-Time Program (OTP) Mode Operation The MP3376A can change the register default values several times with the OTP function. The internal registers 00H, 01H, and 02H can be programmed five times. The internal registers 03H and 04H can only be programmed once. It is recommended to use the sequence below for OTP operation. Note that not all internal registers and bits are programmed respectively. Therefore, write all registers carefully with correct values before setting OTPEN = 1. I2C Chip Address The 7-bit MSB device address is 0x28 ~ 0x2B. After the start condition, the I2C-compatible master sends a 7-bit address followed by an eighth read (1) or write (0) bit. The following bit indicates the register address to or from which the data is written or read. A0 and A1 can program the IC address. Therefore, the four MP3376A chips share the same I2C interface. I2C Compatible Device Address 1. Write the customized default into all internal registers with the I2C when OTMD = 0 (02H - D11) and OTPEN = 0 (02H - D10). 2. Ensure that EN is high and VIN > 8V before entering OTP mode. 3. Set OTPMD = 1 (02H - D11). The IC enters one-time program mode, and the VCC voltage rises to about 6.3V. 4. Set OTPEN = 1 (02H - D10). The MP3376A begins burning the customized default one by one. 5. Burn the registers from 00H to 04H first after enabling the OTP function. 6. Burn the OTP timer (05H-D7:5) last. MP3376A Rev.1.0 8/24/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 15 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C Register Mapping Add 00H Add 00H D15 ISET7 D7 CHEN7 D14 ISET6 D6 CHEN6 D13 ISET5 D5 CHEN5 D12 ISET4 D4 CHEN4 D11 ISET3 D3 CHEN3 D10 ISET2 D2 CHEN2 D9 ISET1 D1 CHEN1 D8 ISET0 D0 CHEN0 Add 01H Add 01H D15 NA D7 SYNC D14 NA D6 MOD2 D13 NA D5 MOD1 D12 NA D4 MOD0 D11 NA D3 ILIM D10 NA D2 FS2 D9 OVP1 D1 FS1 D8 OVP1 D0 FS0 Add 02H Add 02H D15 NA D7 ADIM7 D14 NA D6 ADIM6 D13 NA D5 ADIM5 D12 NA D4 ADIM4 D11 OTPMD D3 ADIM3 D10 OTPEN D2 ADIM2 D9 ADIM9 D1 ADIM1 D8 ADIM8 D0 ADIM0 Add 03H Add 03H D15 NA D7 LEDS1 D14 NA D6 LEDS0 D13 NA D5 FPWM3 D12 NA D4 FPWM2 D11 NA D3 FPWM1 D10 TSLP2 D2 FPWM0 D9 TSLP1 D1 DIMT1 D8 TSLP0 D0 DIMT0 Add 04H Add 04H D15 NA D7 PWM7 D14 NA D6 PWM6 D13 PWM13 D5 PWM5 D12 PWM12 D4 PWM4 D11 PWM11 D3 PWM3 D10 PWM10 D2 PWM2 D9 PWM9 D1 PWM1 D8 PWM8 D0 PWM0 Add 05H Add 05H D15 ID7 D7 TIME2 D14 ID6 D6 TIME1 D13 ID5 D5 TIME0 D12 ID4 D4 FT_OTP D11 ID3 D3 FT_OCP D10 ID2 D2 FT_OVP D9 ID1 D1 FT_LEDO D8 ID0 D0 FT_LEDS NOTES: The register (00H, 01H, 02H) bits in red can be written to a customized default five times. The register (03H, 04H) bits in blue can be written to a customized default once. MP3376A Rev.1.0 8/24/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 16 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C Table 1: Full-Scale and Channel Enable Register Addr: 0x00 Bit Bit Name Access Default 15:8 ISET7:0 RW 0xFF LED current full-scale current bits. These bits set the max current for each channel. 0x00: 0mA; …; 0xFF: 50mA; 0.196mA/step. 0xFF LED current source enable bits. CHEN0-7 bits control the internal LED current sources respectively. CHEN0: 1 = LED current source 1 is enabled 0 = disabled CHEN1: 1 = LED current source 2 is enabled 0 = disabled CHEN2: 1 = LED current source 3 is enabled 0 = disabled CHEN3: 1 = LED current source 4 is enabled 0 = disabled CHEN4: 1 = LED current source 5 is enabled 0 = disabled CHEN5: 1 = LED current source 6 is enabled 0 = disabled CHEN6: 1 = LED current source 7 is enabled 0 = disabled CHEN7: 1 = LED current source 8 is enabled 0 = disabled 7:0 CHEN7:0 MP3376A Rev.1.0 8/24/2017 RW Description www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 17 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C Table 2: Dimming Mode and Parameter Set Register Addr: 0x01 Bit Bit Name Access Default Description 15:10 NA R NA Reserved. 9:8 OVP1:0 RW 01b Output voltage OVP threshold bits. 00 = 24V 01 = 31V 10 = 37.5V 11 = NA 7 SYNC RW 1b Boost converter rectifier operation mode bit. 0 = IC works in non-synchronous mode 1 = IC works in synchronous mode 6:4 MOD2:0 RW 100b 3 ILIM RW 1b 2:0 FS2:0 MP3376A Rev.1.0 8/24/2017 RW 011b LED current dimming mode bits. 000 = the IC works in analog dimming mode through the external PWM input signal. The LED current amplitude changes with the input PWM duty. 001 = the IC works in analog dimming mode through the I2C interface. The LED current amplitude changes with the register PWM13:0 bits. 100 = the IC works in mix dimming mode through the external PWM input signal. If the input PWM duty is higher than the transfer point, the IC works in analog dimming mode. Otherwise, the IC works in PWM dimming mode. The DIMT1:0 bit determines the transfer point of mix dimming mode. 101 = the IC works in mix dimming mode through the I2C interface. If the duty set by the register PWM13:0 bit is higher than the transfer point, the IC works in analog dimming mode. Otherwise, the IC works in PWM dimming mode. The DIMT1:0 bit determines the transfer point of mix dimming mode. Inductor cycle-by-cycle current limit bit of the converter. 0 = 1.8A current limit 1 = 2.5A current limit Boost converter switching frequency bits. 000 = 350kHz 001 = 500kHz 010 = 650kHz 011 = 800kHz 100 = 950kHz 101 = 1.2MHz 110 = 1.8MHz 111 = 2.4MHz www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 18 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C Table 3: One-Time Program Enable and Analog Dimming Register Addr: 0x02 Bit Bit Name Access Default 15:12 NA R NA Reserved. 0b One-time program mode bit. OTP burning must be done in OTP mode. 0 = not OTP mode 1 = enter OTP mode. The VCC voltage rises to about 6.3V if the input voltage >8V. 0b One-time program enable bit. 1 = enable OTP function. Burn the customer’s default to all internal registers one by one (from 00H to 04H) and TIME1:0 bit. Reset to 0 after finishing OTP. 0 = disable OTP function 0x3FF Analog dimming bits. This controls the LED current amplitude in any dimming mode. 0x000 = 0%; 0x001 = 0.098%; …; 0x3FF = 100%; 0.098% per step. 11 10 9:0 OTPMD OTPEN ADIM9:0 MP3376A Rev.1.0 8/24/2017 RW RW RW Description www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 19 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C Table 4: Slope and PWM Dimming Frequency Register Addr: 0x03 Bit Bit Name Access Default 15:11 NA R NA 10:8 7:6 5:2 1:0 TSLP2:0 LEDS1:0 FPWM3:0 DIMT1:0 MP3376A Rev.1.0 8/24/2017 RW RW RW RW Description Reserved. 010b LED current ramp-up/-down slope bit. 000 = 2µs per step 001 = 4µs per step 010 = 8µs per step 011 = 16µs per step 100 = 32µs per step 101 = 64µs per step 110 = 128µs per step 111 = NA 01b LED short protection threshold bits. 00 = 2.5V 01 = 5V 10 = 7.5V 11 = 10V 1111b LED current dimming frequency bits when device is in PWM dimming or mix dimming mode. 0000 = 120Hz 0001 = 240Hz 0010 = 400Hz 0011 = 800Hz 0100 = 1kHz 0101 = 2kHz 0110 = 4kHz 0111 = 10kHz 1000 = 14kHz 1001 = 18kHz 1010 = 22kHz 1011 = 26kHz 1100 = 29kHz 1101 = 33kHz 1110 = 37kHz 1111 = follow PWM input signal when dimming by an external PWM input signal. 10b Transfer point bits in mix dimming mode. If the dimming duty is higher than the threshold, the IC works in analog dimming mode. Otherwise, the IC works in PWM dimming mode. 00 = 6.25% 01 = 12.5% 10 = 25% 11 = 50% www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 20 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C Table 5: Internal I2C Dimming Register Addr: 0x04 Bit Bit Name Access Default 15:14 NA R NA 13:0 PWM13:0 RW 0x0000 Description Reserved. LED current dimming duty setting bit by I2C interface. This controls the LED current dimming duty when set MOD2:0 bit to 001b or 101b. 0x0000: 0%; 0x0001: 0.006%; …; 0x3FFF:100%; 0.006% per step. Table 6: ID and Fault Register Addr: 0x05 Bit Bit Name Access Default 15:8 ID7:0 R 00010001b 7:5 4 3 2 1 0 TIME 2:0 FT_OTP FT_OCP FT_OVP FT_LEDO FT_LEDS MP3376A Rev.1.0 8/24/2017 R R R R R R Description Device ID bits. 000b OTP time bit. When OTP occurs once, TIME2:0 counts one time. 000 = 0 001 = 1 010 = 2 011 = 3 100 = 4 101 = 5 0b Over-temperature protection fault indication bit. 0 = no fault 1 = fault. The fault status can latch off until it is reset to 0 after this bit is read. 0b Over-current protection fault indication bit. 0 = no fault 1 = fault. The fault status can latch off until it is reset to 0 after this bit is read. 0b Over-voltage protection fault indication bit. 0 = no fault 1 = fault. The fault status can latch off until it is reset to 0 after this bit is read. 0b LED current source open fault indication bit. 0 = no fault 1 = fault. The fault status can latch off until it is reset to 0 after this bit is read. 0b LED short fault indication bit. 0 = no fault 1 = fault. The fault status can latch off until it is reset to 0 after this bit is read. www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 21 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C APPLICATION INFORMATION Selecting the Switching Frequency The switching frequency of the step-up converter is set by the register bits FS2:0 (see Table 2). Setting the LED Current The LED string full-scale current is set by the register ISET7:0 bits from 0mA to 50mA with 0.196mA per step. Selecting the Input Capacitor The input capacitor reduces the surge current drawn from the input supply and the switching noise from the device. The input capacitor impedance at the switching frequency should be less than the input source impedance to prevent the high-frequency switching current from passing through to the input. Ceramic capacitors with X5R or X7R dielectrics are recommended for their low ESR and small temperature coefficients. For most applications, a 4.7μF ceramic capacitor is sufficient. Selecting the Inductor The MP3376A requires an inductor to supply a higher output voltage while being driven by the input voltage. A larger value inductor results in less ripple current, lower peak-inductor current, and reduced stress on the internal N-channel MOSFET. However, the larger value inductor also has a larger physical size, higher series resistance, and lower saturation current. Choose an inductor that will not saturate under the worst-case load conditions. Select the minimum inductor value to ensure that the boost converter works in continuous conduction mode with high efficiency and good EMI performance. With a given inductor value, the inductor DC current rating is at least 40% higher than the maximum input peak inductor current for most applications. The inductor’s DC resistance should be as small as possible to achieve higher efficiency. Selecting the Output Capacitor The output capacitor keeps the output voltage ripple small and ensures feedback loop stability. The output capacitor impedance must be low at the switching frequency. Ceramic capacitors with X7R dielectrics are recommended for their low ESR characteristics. For most applications, a 2.2μF ceramic capacitor is sufficient. Setting the Over-Voltage Protection (OVP) The output OVP voltage is set by the register OVP1:0 bits (see Table 2). PCB Layout Guidelines Careful attention must be given to the PCB layout and component placement. Efficient PCB layout of the high-frequency switching path is critical to prevent noise and electromagnetic interference problems. For best results, follow the guidelines below. 1. Keep the loop of SW to PGND, the external diode (if needed), and the output capacitor as short as possible, since it is flowing with a high-frequency pulse current. 2. Place a ceramic capacitor close to the input and VCC, since they are susceptible to noise. Calculate the required inductance value using Equation (1) and Equation (2): L η  VOUT  D  (1 D)2 2  fSW  ILOAD (1) V D  1  IN VOUT (2) Where VIN is the input voltage, VOUT is the output voltage, fSW is the switching frequency, ILOAD is the LED load current, and η is the efficiency. MP3376A Rev.1.0 8/24/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 22 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C TYPICAL APPLICATION CIRCUIT MP1 is Optional for short Vout to GND protection 5, 6, 7, 8 1 2 1 2 100nF C5 NC 6 19 NC SW BST NC 21 20 22 24 23 FT VIN SCL LED1 PWM LED2 A0 LED3 7 2 1 AGND 2 1 NC PGND AGND A1 1 SDA AGND LED4 2k MP3376A EN 12 5 PGND OUT LED6 4 R3 VCC C6 /50V 47 FT 2 3 AGND PGND R5 NC LED5 PWM 1 AGND 11 1 1 2k 10 SCL R1 LED7 1 C2 9 1 25 R7 NC EP R6 LED8 SDA AGND C4 AGND 8 1 R4 PGND 0 EN C3 NC AGND 4.7 D2 NC 1 4 MP1 NC FT C8 NC GND GND D1 NC L1 2 1 C1 4.7 F/50V VIN 1, 2, 3 F1 18 PGND R2 0 LED 17 16 C7 NC PGND LED+ 1 0 LED1 2 14 R15 0 LED2 3 13 R14 0 LED3 4 R13 0 LED4 5 R12 0 LED5 6 R11 0 R10 0 LED6 7 R9 LED8 9 15 R8 0 LED7 8 JP2 JP1 The A0 or A1 is pulled to GND if short JP1 or JP2. Otherwise pulled to high internally Figure 9: Typical Application Circuit MP3376A Rev.1.0 8/24/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 23 MP3376A – 8-CHANNEL, SYNCHRONOUS, BOOST, WLED DRIVER WITH I2C PACKAGE INFORMATION QFN-24 (4mmx4mm) 3.90 4.10 2.50 2.80 19 PIN 1 ID MARKING 18 3.90 4.10 PIN 1 ID INDEX AREA PIN 1 ID SEE DETAIL A 24 1 0.50 BSC 2.50 2.80 0.18 0.30 6 13 0.35 0.45 TOP VIEW 12 7 BOTTOM VIEW PIN 1 ID OPTION A 0.30x45º TYP. PIN 1 ID OPTION B R0.25 TYP. 0.80 1.00 0.20 REF 0.00 0.05 DETAIL A SIDE VIEW 3.90 NOTE: 2.70 1) ALL DIMENSIONS ARE IN MILLIMETERS. 2) EXPOSED PADDLE SIZE DOES NOT INCLUDE MOLD FLASH. 3) LEAD COPLANARITY SHALL BE 0.10 MILLIMETER MAX. 4) DRAWING CONFIRMS TO JEDEC MO-220, VARIATION VGGD. 5) DRAWING IS NOT TO SCALE. 0.70 0.25 0.50 RECOMMENDED LAND PATTERN NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications. MP3376A Rev.1.0 8/24/2017 www.MonolithicPower.com MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited. © 2017 MPS. All Rights Reserved. 24