KTZ8866 KINETIC | Alldatasheet

Document overview

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Technical content

Features

➢ Backlight LED Driver

  • Wide input range: 2.7V~5.5V
  • High efficiency step-up LED driver with 6-Ch current sinks, up to 40V boost voltage. − Up to 30mA/Ch in backlight mode − ±0.7% current matching at 20mA − ±2.2% current accuracy at 20mA
  • I2C/PWM dual dimming control scheme − High resolution I2C 11-bit linear or exponential dimming − Wide range PWM dimming ▪ 100Hz to 100kHz frequency ▪ 0.2% to 100% duty cycle at 20kHz
  • Programmable current sink turn on/off ramp time/shape and transition ramp up/down time
  • 1.0MHz typical boost switching frequency
  • Programmable input PWM hysteresis to minimize jitter at low PWM duty cycle
  • Programmable OVP and current limitation
  • LED open/short protection ➢ LCD Panel Bias
  • Wide input range: 2.7V~5.5V
  • Programmable dual output Bias regulator using a single inductor
  • Programmable ramp time for OUTP and OUTN
  • Charge pump PFM mode at light load
  • LCD Bias efficiency: up to 85%
  • Wide dual output voltage range ±4.0V to ±6.3V (50mV/step) and output current up to 200mA at VIN ≥ 2.9 V
  • Active output discharge function
  • Current limitation and short protection ➢ Others
  • System level input UVLO
  • Thermal shutdown protection
  • Low shutdown current <1µA
  • Flexible I2C interface
  • Pb-free Packages: WLCSP-28
  • RoHS and Green Compliant
  • -40°C to +85°C Temperature Range

Applications

  • Tablet Backlight and Bias Brief Description KTZ8866 is the ideal power solution for LED backlighting and LCD bias power of medium size panels. It integrates a step-up converter for LED backlighting, a step-up converter with LDO and inverting charge pump for LCD b ias power, resulting in a simpler and small er solution with fewer external components. High switching frequency allows the use of a smaller inductor and capacitor. Its input operating range is from 2.7V to 5.5V, accommodating 1 -cell lithium ion batteries or 5V supply. The LED driver’s six regulated current sinks can regulate up to 30mA with its maximum boost output voltage up to 40V. 11-bit linear or exponential ILED resolution can be obtained over I 2C or PWM dimming. For additional flexibility, PWM dimming offers wide range frequency and duty cycle to support Content Adaptive Brightness Control (CABC). The LCD bias power section includes a step-up converter, LDO and an inverting charge pump to generate dual outputs, OUTP and OUTN , whose voltages can be programmed via an I 2C interface. By integrating synchronous rectification MOSFETs for the step -up converter and charge pump, the KTZ8866 maximizes conversion efficiency up to 85%. Various protection features are built into KTZ8866, including inductor current limit p rotection, output short circuit protection, output over-voltage protection, LED fault (open or short) protection and thermal shutdown protection. KTZ8866 is equipped with I2C interface for various controls and status monitor. KTZ8866 is available in a RoHS and Green compliant 28- ball 1.73mm x 2.92mm x 0.62mm WLCSP package. High Efficiency 6-CH LED Backlight Driver with Dual LCD Bias Power

t KTZ8866 January 2022 - Revision 04b Page 2 of 37 Company Confidential Typical Application

t KTZ8866 January 2022 - Revision 04b Page 3 of 37 Company Confidential Pin Descriptions Pin # Name Function A1 OUTN Charge pump output pin of the negative power. Bypass with a 10µF ceramic capacitor to PGND_CHP. A2 CFLY2 Negative charge pump flying capacitor negative connection. A3 PGND_CHP Power ground for negative charge pump. A4 CFLY1 Negative charge pump flying capacitor pin positive connection. B1 VIN Input supply pin for the IC, bypass with a 10µF ceramic capacitor to GND. B2 ENN Enable pin for negative power (OUTN), 300KΩ pull down resistor to GND B3 ENP Enable pin for positive power (OUTP), 300KΩ pull down resistor to GND B4 OUTP LDO output pin of the positive power, bypass with a 10µF ceramic capacitor. C1 S1 Regulated output current sink #1. C2 SCL Clock of the I2C interface. C3 SDA Bi-directional data pin of the I2C interface. C4 REG LCD-Bias Boost converter output pin, bypass a 10µF ceramic capacitor to PGND_LCD D1 S2 Regulated output current sink #2. D2 PWM PWM dimming input pin, 300kΩ pull-down resistor at this pin to GND. D3 HWEN Active high hardware enable pin, 400kΩ pull-down resistor to GND. D4 LX_LCD Switching node of the LCD Bias boost converter. E1 S3 Regulated output current sink #3. E2 SGND Ground pin for sink driver. E3 AGND Analog ground pin. E4 PGND_LCD Power ground for LCD Bias power supply boost converter. F1 S4 Regulated output current sink #4. F2 VOUT Output voltage sense pin of the step-up converter. F3, F4 PGND_BL Power Ground for LED boost converter. G1 S5 Regulated output current sink #5. G2 S6 Regulated output current sink #6. G3, G4 LX_BL Switching pin of the LED step-up converter.

t KTZ8866 January 2022 - Revision 04b Page 4 of 37 Company Confidential WLCSP47-28 ENN SCL SDA REG OUTP PGND_ CHP CFLY1A B C 1 2 3 4 TOP VIEW TOP VIEW ENP CFLY2 VIN OUTN D PWM HWEN LX_LCDS2 SGND AGND PGND_L CDS3 OUT PGND_ BL PGND_ BLS4 E F WW XXYY ZZZZ G S6 LX_BL LX_BLS5 28-Bump 1.73mm x 2.92mm x 0.62mm Top Mark WW = Device ID Code, XX = Date Code YY = Assembly Code, ZZZZ = Serial Number

t KTZ8866 January 2022 - Revision 04b Page 5 of 37 Company Confidential Absolute Maximum Ratings1 (TA = 25C unless otherwise noted) Symbol Description Value Units VIN Input Voltage -0.3 to 6 V LX_BL LX_BL to GND DC -0.3 to 42 V LX_BL to GND AC Transient: 100 ns -1.0 to 44 V VOUT LED Backlight driver output node -0.3 to 42 V S1, S2, S3, S4, S5, S6 LED Backlight driver current sink -0.3 to 32 V HWEN, SCL, SDA, PWM, ENP, ENN Control Pins -0.3 to VIN+0.3 V LX_LCD, CFLY1, OUTP, REG LCD Bias power positive voltage and switching node -0.3 to 7 V OUTN, CFLY2 LCD Bias power negative output voltage and switching node -7 to 0.3 V TJ Junction Operating Temperature Range -40 to 150 °C TS Storage Temperature Range -65 to 150 °C TLEAD Maximum Soldering Temperature (at leads, 10 sec) 300 °C ESD Ratings Symbol Description Value Units VESD Human body model (HBM), per ANSI/ESDA/JEDEC JS-001 ±2000 V Charge device model (CDM), per JEDEC specification JESD22-C101 ±500 V Thermal Capabilities2 Symbol Description Value Units θJA Thermal Resistance – Junction to Ambient 66.8 C/W PD Maximum Power Dissipation at TA ≤ 25°C 1870 mW ΔPD/ΔT Derating Factor Above TA = 25°C -14.97 mW/°C

Ordering Information

Part Number Marking3 Operating Temperature Package KTZ8866EKAA-TR PRXXYYZZZZ -40°C to +85°C WLCSP-28 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum rating should be applied at any one time. 2. Junction to Ambient thermal resistance is highly dependent on PCB layout. Values are based on thermal properties of the device when soldered to an EV board. 3. PR = Device ID Code, XX = Date Code, YY = Assembly Code, ZZZZ = Serial Number.

t KTZ8866 January 2022 - Revision 04b Page 6 of 37 Company Confidential Electrical Characteristics4 Unless otherwise noted, the Min and Max specs are applied over the full operation temperature range of –40°C to +85°C, while Typ values are specified at room temperature (25°C). VIN = 3.6V. Symbol Description Conditions Min Typ Max Units IC Supply VIN Input operating range 2.7 5.5 V UVLO Input under voltage lockout Rising edge 2.45 2.65 V UVLOHYST UVLO hysteresis 0.05 V IQ IC standby current HWEN = VIN, LCD Boost disabled, LED Boost and Current Sink disabled. 1 7 µA ILCD_EN Bias power no load current LED Boost and Current Sink disabled. OUTP, OUTN enabled with no load. 1.1 1.3 mA ISHDN IC shutdown VIN current HWEN = 0, ENP = ENN = GND 1 3 µA Boost Converter for LED Backlight RDS(ON) NMOS on-resistance VIN=3.6V, ISW = 250mA, TA = 25°C 0.2 0.3 Ω ILIM Peak NMOS current limit Reg 0x11[1:0]=00, TA = 25°C 1.02 1.2 1.38 A FSW Oscillator frequency TA = 25°C 0.9 1.0 1.1 MHz EFFLEDBST Boost Efficiency5 VIN = 3.6V, ILED = 5mA/ch, 6P6S LEDS, Typical application circuit. 87 % DMAX Maximum duty cycle5 FSW = 1MHz, TA = 25°C 89 94 % VOVP OVP threshold Reg 0x02[7:5]=111, default, TA = 25°C 38.5 40 41.3 V OVP hysteresis 2 V 4. KTZ8866 is guaranteed to meet performance specifications over the –40°C to +85°C operating temperature range by design, characterization and correlation with statistical process controls. 5. Guarantee by characterization and/or simulation.

t KTZ8866 January 2022 - Revision 04b Page 7 of 37 Company Confidential Electrical Characteristics4 Unless otherwise noted, the Min and Max specs are applied over the full operation temperature range of –40°C to +85°C, while Typ values are specified at room temperature (25°C). VIN = 3.6V. Symbol Description Conditions Min Typ Max Units Current Sink for LED Backlight ISINK_ACC Output current accuracy Current setting = 30mA, TA = 25°C -2.0 2.0 % Current setting = 20mA, TA = 25°C -2.2 2.2 % Current setting = 1mA, TA = 25°C -3.0 3.0 % ISINK_MATCH Output current matching6 Current setting = 30mA, TA = 25°C -0.7 0.7 % Current setting = 20mA, TA = 25°C -0.7 0.7 % Current setting = 1mA, TA = 25°C -1.5 1.5 % VHR Current sink head room voltage 0.45 V ILED_MIN Minimum LED current per string Linear or Exponential mapping 60 µA ISTEP LED step size5 Exponential Mode 0.3 % Linear Mode 14.63 µA VSOV Current sink over voltage threshold5 6 V TFAULT Current sink fault delay 50 60 70 ms Boost Converter for LCD Power Bias VREG LCD boost output voltage range 4 6.6 V LCD boost output voltage step size5 50 mV IREG_LIM Peak current limit VIN = 3.6V, TA = 25°C 1.3 1.45 A FSW Oscillator frequency Continuous Mode, TA = 25°C 1.8 2.0 2.2 MHz EFFLCDBST Efficiency5 VIN = 3.6 V, VREG_OUT = 5.9 V, 6mA < IO < 400mA, Typical application circuit 85 % RON_HS High side FET on resistance VIN = 3.6V, TA = 25°C 390 500 mΩ RON_LS Low side FET on resistance VIN = 3.6V, TA = 25°C 200 250 mΩ VREG_PP LCD boost output ripple5 Io = 5mA and 200mA, Co = 10µF 50 mVPP DMAX Maximum duty cycle 80 86 % OUTP-Positive Output OUTP Positive output voltage range 4.0 6.3 V Output voltage step size5 50 mV Output voltage accuracy VOUTP = 5.5V, no load -1.5 +1.5 % IOUTP_MAX Maximum output current limit 200 mA IOUTP_LIM Positive output current limit VIN = 3.6V, TA = 25°C 200 255 300 mA VOUTP_LOREG VOUTP LDO load regulation5 0 ≤ Io ≤ IOUTP_MAX 80 mV VOUTP_DO VOUTP LDO dropout voltage5 IOUTP = IOUTP_MAX, VOUTP = 5.5V 200 mV TOUTP_SS Startup time Co = 10µF, VOUTP = 5.75V, VOUTP_RAMP = 2b’01 456 µs RPD_OUTP Output pulldown resistor in shutdown 40 70 100 Ω 6 . The current matching among channels is defined as |ISINK-IAVG|MAX/IAVG.

t KTZ8866 January 2022 - Revision 04b Page 8 of 37 Company Confidential Electrical Characteristics4 Unless otherwise noted, the Min and Max specs are applied over the full operation temperature range of –40°C to +85°C, while Typ values are specified at room temperature (25°C). VIN = 3.6V. Symbol Description Conditions Min Typ Max Units OUTN-Negative Output OUTN Negative output voltage range -6.3 -4.0 V Output voltage step size5 50 mV Output voltage accuracy VOUTN = -5.4V, no load -1.5 +1.5 % IOUTN_MAX Maximum output current limit 200 mA EFFCHP Inverting charge pump efficiency5 VREG = 5.7 V, VOUTN = –5.4V, IOUTN > –5mA 85 % TOUTN_SS Startup time Co = 10µF, VOUTN = -5.75V, VOUTN_RAMP = 4b’0001 912 µs RPD_OUTN Output pulldown resistor in shutdown 20 35 Ω PWM INPUT5 fPWM_INPUT PWM input frequency 0.1 100 kHz tMIN_ON Minimum pulse ON time 150 ns tMIN_OFF Minimum pulse OFF time 150 ns PWMRES PWM input resolution 100Hz < fPWM < 10KHz 11 bit I2C-Compatible Voltage Specifications (SCL, SDA, ENP, ENN, PWM, HWEN) VIL Input Logic Low Threshold 0.4 V VIH Input Logic High Threshold 1.2 V VOL SDA Output Logic Low ISDA = 3mA 0.4 V RPDHWEN Pulldown resistance on HWEN pin 300 KΩ RPDPWM Pulldown resistance on PWM pin 300 KΩ RPDENP Pulldown resistance on ENP pin 300 KΩ RPDENN Pulldown resistance on ENN pin 300 KΩ

–40°C to +85°C, while Typ values are specified at room temperature (25°C). VIN = 3.6V. Figure 1. I2C Compatible Interface Timing

t KTZ8866 January 2022 - Revision 04b Page 10 of 37 Company Confidential Typical Characteristics LED Backlight VIN = 3.6V, 6P6S LEDs, I LED = 30mA, L = 6.8µH (ECS ECS -MPI4040R4-6R8-R), CIN = 10µF, C OUT = 4.7µF, I2C register default settings, Temp = 25°C unless otherwise specified. Efficiency (%) Input Voltage (V) LED Driver Efficiency vs. VIN (ILED = 30mA) 6P6S 6P5S 6P7S 100 0 20 40 60 80 100 120 140 160 180 Efficiency (%) Output Current (mA) LED Driver Efficiency vs. VIN 6P5S 6P6S 6P7S 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 BL Operation Current (mA) Input Voltage (V) Operating Current (Switching) 0.90 0.92 0.94 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10 Switching Frequency (MHz) Input Voltage (V) Switching Frequency vs. VIN 0.5 0.6 0.7 0.8 0.9 1.0 Vth (V) Input Voltage (V) HWEN Logic Threshold Voltage Vth-L Vth-H 0.5 0.6 0.7 0.8 0.9 1.0 Vth (V) Input Voltage (V) PWM Logic Threshold Voltage Vth-L Vth-H

t KTZ8866 January 2022 - Revision 04b Page 11 of 37 Company Confidential Typical Characteristics (continued) LED Backlight VIN = 3.6V, 6P6S LEDs, I LED = 30mA, L = 6.8µH (ECS ECS -MPI4040R4-6R8-R), CIN = 10µF, C OUT = 4.7µF, I2C register default settings, Temp = 25°C unless otherwise specified. 0 400 800 1200 1600 2000 2400 LED Current (mA) Dimming Code LED Current vs. Current Ratio Code (11 bits, Exponential) CH1 CH2 CH3 CH4 CH5 CH6 0 400 800 1200 1600 2000 2400 LED Current (mA) Dimming Code LED Current vs. Current Ratio Code (11 bits, Linear) CH1 CH2 CH3 CH4 CH5 CH6 0 10 20 30 40 50 60 70 80 90 100 LED Current (mA) Dimming Duty (%) LED Current vs. PWM Duty Cycle (20kHz) CH1 CH2 CH3 CH4 CH5 CH6 27.5 28.0 28.5 29.0 29.5 30.0 30.5 31.0 31.5 32.0 32.5 LED Current (mA) Input Voltage (V) LED Current Line Regulation CH1 CH2 CH3 CH4 CH5 CH6 6P6S PWN 2V / div VOUT 10V / div Inductor Current 500mA / div I_S1 20mA / div 4.0ms / div Turn On by PWM PWN 2V / div VOUT 10V / div Inductor Current 500mA / div I_S1 20mA / div 4.0ms / div Turn Off by PWM

t KTZ8866 January 2022 - Revision 04b Page 12 of 37 Company Confidential Typical Characteristics (continued) LED Backlight VIN = 3.6V, 6P6S LEDs, I LED = 30mA, L = 6.8µH (ECS ECS -MPI4040R4-6R8-R), CIN = 10µF, C OUT = 4.7µF, I2C register default settings, Temp = 25°C unless otherwise specified. SDA 5V / div VOUT 10V / div Inductor Current 500mA / div I_S1 20mA / div 4.0ms / div Turn On by I2C (8ms) SDA 5V / div VOUT 10V / div Inductor Current 500mA / div I_S1 20mA / div 4.0ms / div Turn Off by I2C (8ms) PWM 2V / div I_S1 20mA / div 100ms / div Ramp Up/Down Exponential (256ms) PWM 2V / div I_S1 20mA / div 100ms / div Ramp Up/Down Exponential (256ms) LX 10V / div VOUT (AC) 200mA / div Inductor Current 500mA / div 1.0µs / div Steady State Switching SDA 2V / div VOUT (AC) 100mV / div I_S1 10mA / div 40µs / div PWM Dimming (20kHz)

t KTZ8866 January 2022 - Revision 04b Page 13 of 37 Company Confidential Typical Characteristics (continued) LED Backlight VIN = 3.6V, 6P6S LEDs, I LED = 30mA, L = 6.8µH (ECS ECS -MPI4040R4-6R8-R), CIN = 10µF, C OUT = 4.7µF, I2C register default settings, Temp = 25°C unless otherwise specified. SDA 5V / div VOUT 10V / div Inductor Current 500mA / div 400µs / div Turn On with LED Open (OVP = 40V) SDA 5V / div VOUT 10V / div Inductor Current 500mA / div 400µs / div Turn On with LED Open (OVP = 21.4V)

t KTZ8866 January 2022 - Revision 04b Page 14 of 37 Company Confidential Typical Characteristics (continued) LCD Bias VIN = 3.6V, L = 2.2µH (TOKO DFE201612P-2R2M=P2), CIN = CREG = CPOS = CNEG = 10µF, CFLY = 4.7µF, IOUTP = -IOUTN = 100mA, TA = 25°C, unless otherwise specified. Default setting VOUTP /VOUTN = ±5.5V, VREG = 5.8V. 0 20 40 60 80 100 120 140 160 180 200 Efficiency (%) Ioutp/Ioutn (mA) Efficiency vs. Output Current VIN = 3.6V VIN = 4.2V 0.5 0.6 0.7 0.8 0.9 1.0 Vth (V) Input Voltage (V) ENP/ENN Logic Threshold Voltage Vth-H Vth-L 0.95 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04 1.05 Normalized OUTP (V) Input Voltage (V) OUTP Line Regulation Normalized to 3.6V IOUTP = 100mA 0.95 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04 1.05 Normalized OUTN (V) Input Voltage (V) OUTN Line Regulation Normalized to 3.6V IOUTN = 100mA 5.38 5.40 5.42 5.44 5.46 5.48 5.50 5.52 5.54 5.56 5.58 0 20 40 60 80 100 120 140 160 180 200 OUTP (V) I_OUTP (mA) OUTP Load Regulation VIN = 3.6V -5.58 -5.56 -5.54 -5.52 -5.50 -5.48 -5.46 -5.44 -5.42 -5.40 -5.38 0 20 40 60 80 100 120 140 160 180 200 OUTN (V) I_OUTN (mA) OUTN Load Regulation VIN = 3.6V

t KTZ8866 January 2022 - Revision 04b Page 15 of 37 Company Confidential Typical Characteristics (continued) LCD Bias VIN = 3.6V, L = 2.2µH (TOKO DFE201612P-2R2M=P2), CIN = CREG = CPOS = CNEG = 10µF, CFLY = 4.7µF, IOUTP = -IOUTN = 100mA, TA = 25°C, unless otherwise specified. Default setting VOUTP /VOUTN = ±5.5V, VREG = 5.8V. OUTN 2V / div REG 2V / div OUTP 2V / div 400µs / div Power-up (No Load) OUTN 2V / div REG 2V / div OUTP 2V / div 400µs / div Power-down (No Load) OUTP (AC Coupled) 10mV / div OUTN (AC Coupled) 50mV / div 100µs / div Steady-state Operation (IPOS = -INEG = 5mA) OUTP (AC Coupled) 10mV / div OUTN (AC Coupled) 20mV / div 4µs / div Steady-state Operation (IPOS = -INEG = 100mA) OUTP (AC Coupled) 20mV / div I_OUTP) 100mV / div 1ms / div Load Transient (5mA to 100mA Step Load) (OUTN = No Load) OUTN (AC Coupled) 20mV / div OUTP (AC Coupled) 20mV / div I_OUTN) 100mV / div 1ms / div Load Transient (5mA to 100mA Step Load) (OUTP = No Load) OUTN (AC Coupled) 50mV / div

t KTZ8866 January 2022 - Revision 04b Page 16 of 37 Company Confidential Functional Block Diagram LED Step-Up Converter Control Over Voltage Protection LED Open/Short Protection VSINK FB Control

6 Channel

PGND_BL VIN HWEN PWM SCL SDA ENP ENN LX_LCD PGND_LCD AGND PGND_CHP CFLY1 CFLY2 OUTN OUTP REG LX_BL VOUT SGND

t KTZ8866 January 2022 - Revision 04b Page 17 of 37 Company Confidential Functional Description Overview KTZ8866 is the ideal power solution for LED backlighting and LCD bias power of small and medium size panels. It integrates a step-up converter for LED backlighting, a step-up converter with LDO and inverting charge pump for LCD bias power, resulting in a simpler and smaller solution with fewer external components. High switching frequency allows the use of smaller inductor s and capacitor s. Its operating input ranges from 2.7V to 5.5V, accommodating 1-cell lithium ion batteries or 5V supply. The LED driver’s six regulated current sinks can regulate up to 30mA in backlight mode with its maximum boost output voltage up to 40V. 11bit linear or exponential I LED resolution can be obtained over I2C or PWM diming. For additional flexibility, PWM dimming offers wide range frequency and duty cycle to support Content Adaptive Brightness Control (CABC). The LCD bias power includes a step-up converter, LDO and an inverting charge pump to generate dual outputs, OUTP and OUTN , whose voltages can be programmed via an I 2C interface. By integrating synchronous rectification MOSFETs for the step -up converter and charge pump, the KTZ8866 maximizes conversion efficiency up to 85%. Various protection features are built into KTZ8866, including inductor current limit protection, output short circuit protection, output over-voltage protection, LED fault (open or short) protection and thermal shutdown protection. KTZ8866 is equipped with I2C interface for various controls and status monitor. Hardware Enable & Standby Mode KTZ8866 has a logic input HWEN pin to enable/disable the device. When HWEN is set low, the device goes into shutdown mode, all I2C registers are reset to default, and the I2C interface is disabled. Under this condition, the device does not respond to any I 2C command. Even when SCL/SDA’s pull up voltage is much less than VIN voltage, it will not cause any extra leakage current. When HWEN is set high, the device goes into standby mode, the I 2C interface is enabled, and the device can respond to I2C command. Under this condition, if SCL/SDA’s pull up voltage is much less than VIN voltage, it can cause a small leakage current from VIN. For example, if VIN = 4.2V and SCL/SDA’s pull up voltage is 1.8V, there will be around 6.8µA additional leakage current from VIN in this standby mode. Based on HWEN’s connection, there are two kinds of power-up sequences as below

  • If HWEN is tied to VIN, once VIN goes above around 2.0V, HWEN should stay high for at least TI2C_RESET = 150s time before any I2C command can be accepted.
  • If HWEN is driven by a GPIO, once HWEN goes from low to high, HWEN should stay high for at least TI2C_RESET = 150s time before receiving any I2C command. Either HWEN input or I2C command can be used to turn off the part, but there are some differences.
  • If setting HWEN input low to turn off the part, the ILED will be turned off immediately without any ramp down control. After that, the I2C interface is disabled.
  • If using an I2C command to turn off backlight while keeping HWEN high, the ILED will have ramp down control. After the LED current ramp down is finished, the I2C interface is still alive waiting for new command. Backlight Boost A step -up converter is used to generate high voltage for driving LED string s. An adaptive control method automatically adjusts output voltage by monitoring the headroom voltage of current sinks. In this way, KTZ8866 can offer much better efficiency. The switching frequency of KTZ8866 Backlight Boost is typical 1.0MHz. Backlight Current Sink Setting Each current sink can be enabled or disabled by register 0x08 bits [5:0]. They can be enabled by writing the backlight enable bit to HIGH in register 0x08 bit [6] after correctly setting of LED configuration and brightness. If a current sink is not used, connect its output to GND. During the startup, KTZ8866 will automatically detect and disable the corresponding channel.

controlled current and with PWM controlled current. Figure 2. Enable of KTZ8866 via I2C Figure 3. Enable of KTZ8866 via PWM Table 1. Backlight Operating Modes

0 X X X X X X X Shutdown

  1. Standby signifies that the backlight boost and current sinks are shut down. Register writes are still possible. Shutdown signifies that that

the device was reset and no I2C communication is accepted.

t KTZ8866 January 2022 - Revision 04b Page 19 of 37 Company Confidential Backlight LED Current The LED current is always a DC current (not PWM). It can be programmed for either exponential mapping mode or linear mapping mode by Register 0x0 2 bit [3]. These two modes determine the transfer characteristic of dimming code to LED current. It also has 11 -bit control, including the 8 -bit MSBs from register 0x05 bits [7:0] and the 3-bit LSBs from register 0x04 bits [2:0]. If only 8-bit dimming is needed, the 3 -bit LSBs should be kept as ‘111’ while the 8 -bit MSBs are programmed. If 11 -bit dimming ratio is needed, the 3 -bit LSBs should be programmed first, then the 8 -bit MSBs are programmed. Only pro gramming the 3-bit LSBs doesn’t change the current ratio until the 8-bit MSBs are programmed. In linear mapping 8-bit dimming mode, the LED current per channel can be calculated as: 𝐼𝐿𝐸𝐷_𝐵𝐿 = 𝐼𝐿𝐸𝐷_𝐹𝑆 ∗ 𝐷𝑃𝑊𝑀 ∗ ( 3 2050 + 𝐶𝑜𝑑𝑒 ∗ 8 + 7 where ILED_FS is the backlight full-scale LED current which is programmed by 0x15 bits [7:3], ranges from 5.2mA to 30mA with 0.8mA step, DPWM is the input PWM duty cycle if PWM dimming is enabled, otherwise DPWM = 1. In linear mapping 11-bit dimming mode, the LED current per channel can be calculated as: 𝐼𝐿𝐸𝐷_𝐵𝐿 = 𝐼𝐿𝐸𝐷_𝐹𝑆 ∗ 𝐷𝑃𝑊𝑀 ∗ ( 3 2050 + 𝐶𝑜𝑑𝑒 For linear mapping 11-bit dimming’s Code 0, current sink and boost converter will be disabled, LED will be turned off. In exponential mapping 8-bit dimming mode, the LED current per channel can be calculated as: 𝐼𝐿𝐸𝐷_𝐵𝐿 = 𝐼𝐿𝐸𝐷_𝐹𝑆 ∗ 𝐷𝑃𝑊𝑀 ∗ 1.003040572(𝐶𝑜𝑑𝑒∗8+7) 500 (𝐶𝑜𝑑𝑒 = 0~255) In exponential mapping 11-bit dimming mode, the LED current per channel can be calculated as: 𝐼𝐿𝐸𝐷_𝐵𝐿 = 𝐼𝐿𝐸𝐷_𝐹𝑆 ∗ 𝐷𝑃𝑊𝑀 ∗ 1.003040572𝐶𝑜𝑑𝑒 500 (𝐶𝑜𝑑𝑒 = 1~2047) For exponential mapping 11 -bit dimming’s Code 0, current sink and boost converter will be disabled, LED will be turned off. Backlight Brightness Control Mode KTZ8866 has two brightness control mode, I 2C Only Mode and I2C x PWM Mode, see Figure 4. In I 2C Only Mode, register 0x02’s bit [0] PWM_ENABLE should be set to “0”, the LED brightness is control led by registers 0x04 and 0x05. In I 2C x PWM Mode, register 0x02’s bit [ 0] PWM_ENABLE should be set to “1”, the LED brightness will be controlled by I2C code and PWM duty together. If the LED current is changed from one value to the other by I2C dimming Register 0x04 and Register 0x05, the ramp time can help LED current transit smoothly from one brightness level to next one. Ramp time can be adjusted from 1µs to 640ms via 0x03’s bits [6:3]. Ramp time applies both to ramp up and ramp down, it remains same regardless the amount of change in brightness.

Figure 4. I2C and PWM Dimming Scheme sampling clock to detect the PWM duty cycle. It is recommended to ha ve the minimum PWM on time as 0.1 s. dimming frequency range can be as wide as 100Hz to 100kHz. final transition ramp time is dependent on the change amount of the PWM duty cycle. and multiply it by the brightness level setting in the brightness registers (0x04 and 0x05).

of setting PWM hysteresis too high is that the output current becomes less accurate due to the hysteresis. Table 2. PWM Hysteresis Table 3. Register 0x03 Bits [2:0]’s Minimum Setting can also be programmed as exponential or linear through the Register 0x02 bit [1], with linear as default. without turning off the shorted channel’s current sink until it reaches thermal shutdown.

voltage threshold, all the current sinks will be disabled internally and the boost converter will stop switching. User needs to restart the IC by toggling HWEN or sending software reset command or resetting backlight mode. threshold events occur, the BL_OCP Flag (register 0x0F, bit [0]) will be set. boost ranges from 4V to 6.6V with 50mV step size. OUTP is generated by an LDO whose input is REG pin. supports up to 200mA output current. Refer to 0x0C, 0x0D, 0x0E for the settings of REG, OUTP and OUTN. for lower currents and 𝑉𝐻𝑅 ≥ 300𝑚𝑉 for higher currents. select on/off is controlled by external pins or internal register bits. Refer to Table 4 for detailed information. Table 4. LCD Bias Power Operating Mode

0 X X X X X X Device shutdown

1 X X 1 0 0 0 Standby8

1 X X 1 1 0 0 VOUTP enabled via I2C

1 X X 1 0 1 0 VOUTN enabled via I2C

1 X X 1 1 1 0 VOUTP and VOUTN enabled via I2C

  1. Standby signifies that OUTP and OUTN are either high impedance or being internally pulled low via the active pulldown, and that the LCD

boost is off. Shutdown signifies that that the device was reset and no I2C communication is accepted.

t KTZ8866 January 2022 - Revision 04b Page 23 of 37 Company Confidential Fast Discharge KTZ8866 has internal switch resistance for discharging OUTP and OUTN when device is shutdown . The OUTP discharge function is enabled with register 0x09 bit [4] and the OUTN discharge is enabled with register 0x09 bit [3]. OUTP Short Circuit Protection If output current of OUTP is greater than 240mA (typical), the OUTP_SHORT flag will be set in register 0x0F. A I2C readback is required to clear the flag. The outcome of an OUTP_SHORT detection depends on the setting of register 0x0A bits [7:6], including report-only flag, shutdown OUTP/OUTN, and shutdown OUTP/OUTN and backlight. KTZ8866 provides four level short circuit detection filter: 100μs, 500μs, 1ms, and 2ms by register 0x0B bits [3:2] to avoid false trigger problems. OUTN Short Circuit Protection OUTN_SHORT flag will be set in register 0x0F if OUTN is found shorted to ground. An I2C readback of register 0x0F is required to clear the flag. The outcome of an OUTN_SHORT detection depends on the setting of register 0x0A bits [7:6], including report -only flag, shutdown OUTP/OUTN, and shutdo wn OUTP/OUTN and backlight . KTZ8866 provides four level short circuit detection filter options: 100μs, 500μs, 1ms, and 2ms by register 0x0B bits [1:0] to avoid false trigger problems. Soft Reset All the I2C registers can be reset to their default settings by writing ‘1’ to the SOFTWARE_RESET bit in Register 0x08, this bit will be reset to ‘0’ automatically after the software reset. UVLO Under voltage lock -out (UVLO) featured is included to monitor the input voltage VIN. Once VIN drops below UVLO falling threshold, the current sinks are disabled and the boost converter s stop switching. After VIN increases above UVLO rising threshold, the boost converters and the current sinks will resume to their previous setting. Thermal Shutdown The KTZ8866 has Thermal Shutdown Protection which will turn off the backlight boost, all current sinks, LC D bias boost, inverting charge pump, and the LDO when the die temperature reaches or exceeds 150°C (typ). The I2C access is still available during Thermal Shutdown event, but TSD flag will be set in register 0x0F , this bit is real time reflection of TSD. When TSD is gone, the bit will be reset back to 0 automatically. Device Functional Modes Shutdown: The KTZ8866 is in shutdown when the HWEN pin is low. I2C writes are not recognized in shutdown. Standby: After the HWEN pin is set high the KTZ8866 goes into standby mode. In standby mode, I2C writes are allowed but references, bias currents, the oscillator, LC D Bias, and backlight are all disabled to keep the quiescent supply current low. Normal mode: Each of the main blocks of the KTZ8866 are independently controlled. For details on how to control each mode, see Tables 1 and 4.

t KTZ8866 January 2022 - Revision 04b Page 24 of 37 Company Confidential

Application Information

KTZ8866 supports the I2C bus protocol. A device that sends data onto the bus is defined as a transmitter and a device receiving data as a receiver. The device that controls the bus is called a master, whereas the devices controlled by the master are known as slaves. A master device must generate the serial clock (SCL), control bus access and generate START and STOP conditions to control the bus. KTZ8866 operates as a slave on the I2C bus. Within the bus specifications a standard mode (100kHz maximum clock rate) and a fast mode (400kHz maximum clock rate) are defined. KTZ8866 works in both modes. Connections to the bus are made through the open-drain I/O lines SDA and SCL. The following bus protocol has been defined in Figure 5:

  • Data transfer may be initiated only when the bus is not busy.
  • During data transfer, the data line must remain stable whenever the clock line is HIGH. Changes in the data line while the clock line is high are interpreted as control signals. Accordingly, the following bus conditions have been defined: Bus Not Busy Both data and clock lines remain HIGH. Start Data Transfer A change in the state of the data line, from HIGH to LOW, while the clock is HIGH, defines a START condition. Stop Data Transfer A change in the state of the data line, from LOW to HIGH, while the clock line is HIGH, defines the STOP condition. Data Valid The state of the data line represents valid data when, after a START condition, the data line is stable for the duration of the HIGH period of the clock signal. The data on the line must be changed during the LOW period of the clock signal. There is one clock pulse per bit of data. Each data transfer is initiated with a START condition and terminated with a STOP condition. The number of data bytes transferred between START and STOP conditions are not limited and are determined by the master device. The information is transferred byte-wise and each receiver acknowledges with a ninth bit. Acknowledge Each receiving device, when addressed, is obliged to generate an acknowledge after the reception of each byte. The master device must generate an extra clock pulse that is associated with this acknowledge bit. A device that acknowledges must pull down the SDA line during the acknowledge clock pulse in such a way that the SDA line is stable LOW during the HIGH period of the acknowledge -related clock pulse. Setup and hold times must also be taken into account.

Figure 5. Data Transfer on I2C Serial Bus KTZ8866 7-bit slave device address is 0010001 binary (0x11h).

to default values by VIN power on reset, toggling HWEN or I2C software reset. Table 5. I2C Register Map Table 6. Device ID Register

Table 7. BL_CFG1 Register

4 OVP_MODE 1 0: OVP is report only

3 BLED_MAP 1 0: Exponential

2 PWM_CONFIG 0 0: Active high (Default)

1 RAMP_SHAPE 1 0: Exponential

0 PWM_ENABLE 0 0: PWM disabled (Default)

Note: When Backlight Current Mapping setting is changed, the LED current change will not take effect until Register 0x05 is p rogrammed. Table 8. BL_CFG2 Register

7 RSVD 1 Reserved (Must be 1)

  1. For LED CURRENT RAMP Time in the table, all the ramp times are fixed when current ramps from one level to the other except "0000" setting. For

"0000" setting, the ramp slope is 1µs/step, the final ramp time is proportional to the 11-bit current steps.

Table 9. BL_BRT_LSB Register Table 10. BL_BRT_MSB Register

  1. If only using 8-bit current ratio, keep the 3-bit LSBs as ‘111’ and only program the 8-bit MSBs.
  2. If using 11-bit current ratio, the 3-bit LSBs should be programmed first, then the 8-bit MSBs can be programmed to take effect. Even if only the 3 -bit LSBs

need to be changed, the 8-bit MSB should always be programmed to make the 3-bit LSBs change taking effect.

  1. For 11-bit program code 11’b00000000000, both boost converter and current sinks are turned off.

Table 11. BL_EN Register

7 SOFTWARE_RESET 0 0 = No reset (Default)

6 BL_EN 0 0 = BL disabled (Default)

5 LED6_EN 1 0 = Current sink 6 disabled

4 LED5_EN 1 0 = Current sink 5 disabled

3 LED4_EN 1 0 = Current sink 4 disabled

2 LED3_EN 1 0 = Current sink 3 disabled

1 LED2_EN 1 0 = Current sink 2 disabled

0 LED1_EN 1 0 = Current sink 1 disabled

Note: Writing software reset bit to ‘1’ will reset all I2C registers to their default values, then this bit will be internally reset back to ‘0’.

Table 12. LCD_CFG1 Register

7 LCD_EN 0 0 = Bias supply off (I2C and external) (Default)

4 OUTP_DISCH 1 0 = No pulldown on OUTP

3 OUTN_DISCH 1 0 = No pulldown on OUTN

2 OUTP_EN 0 0 = OUTP disabled (Default)

1 OUTN_EN 0 0 = OUTN disabled (Default)

0 EXT_EN 0

via pin ENP and ENN, respectively. Table 13. LCD_CFG2 Register

  1. For VOUTP_RAMP time, it is fixed slew rate ramp strategy, the ramp time value is given by assuming OUTP = 5.75V. If OUTP is set 5.5V and

VOUTP_RAMP = 01, then actual ramp time will be 456*5.5/5.75 = 436µs.

  1. For VOUTN_RAMP time, it is fixed slew rate ramp strategy, the ramp time value is given by assuming OUT N = -5.75V. If OUTN is set -5.5V and

VOUTN_RAMP = 0001, then actual ramp time will be 912*5.5/5.75 = 872µs.

Table 14. LCD_CFG3 Register Table 15. LCD_BOOST_CFG Register Table 16. OUTP_CFG Register Note: Writing to Register 0x0D will not take effect immediately, until Register 0x09 is written again. Table 17. OUTN_CFG Register Note: Writing to Register 0x0E will not take effect immediately, until Register 0x09 is written again.

Table 18. FLAG Register

7 LED_SHORT 0 0 = Normal operation

1 = LED short protection trigged.

6 TSD 0 0 = Normal operation

5 RSVD 0

4 RSVD 0

3 OUTP_SHORT 0 0 = Normal operation

2 OUTN_SHORT 0 0 = Normal operation

1 BL_OVP 0 0 = Normal operation

0 BL_OCP 0 0 = Normal operation

  1. TSD is real-time results.
  2. LED_SHORT, OUTP_SHORT, OUTN_SHORT, BL_OVP and BL_OCP are latched results; OUTP_SHORT, OUTN_SHORT, BL_OVP and BL_OCP can

be reset by reading back 0x0F.

  1. All the status bits can be reset by VIN power on reset, software reset or toggling HWEN.

Table 19. BL_OPTION1 Register

7 LED_SHORT_MODE 1

0 = Will keep all strings on.

6 LED6_FB_DISABLE 0 0 = Feedback enabled (Default)

5 LED5_FB_DISABLE 0 0 = Feedback enabled (Default)

4 LED4_FB_DISABLE 0 0 = Feedback enabled (Default)

3 LED3_FB_DISABLE 0 0 = Feedback enabled (Default)

2 LED2_FB_DISABLE 0 0 = Feedback enabled (Default)

1 LED1_FB_DISABLE 0 0 = Feedback enabled (Default)

0 RSVD 0

Note: If all LED1~LED6 disabled, Boost stops switching. Table 20. BL_OPTION2 Register

Table 21. PWM2DIG_LSBs Register Table 22. PWM2DIG_MSBs Register cause incorrect returned result, since input PWM may change during the delay time. Table 23. TURN_ON/OFF_RAMP Register

Table 24. PWM_UP/DOWN_RAMP Register in the table and the difference of the PWM duty cycle change. duty cycle. The final transition time is the multiplication of the time in the table and the change of the PWM duty cycle.

25 shows the recommended capacitor vendors. Table 25. Recommended Capacitor Vendors efficiency under that condition. Table 26 shows recommended inductors under different application conditions. Table 26. Recommended Inductors Using a schottky diode is recommended because of its low forward voltage drop and fast reverse recovery time. shows the recommended schottky diode. Table 27. Recommended Schottky Diode should be as close as possible to the IC.

12 MAXOUT

t KTZ8866 January 2022 - Revision 04b Page 35 of 37 Company Confidential Flying Capacitor Selection for Bias The charge pump needs an external flying capacitor. The minimum value for smartphone application is 4.7μF and 10μF for tablet application. Special care must be taken while choosing the flying capacitor as it will directly impact the output voltage accuracy and load regulation performance. Inductor Selection for Dual Output Bias An inductor in the range of 2.2µH to 10µH with low DCR can be selected for the boost converter. To estimate the inductance required for applications, calculate the maximum input average current as the following Where, η is the converter efficiency and can be approximated as 90% for the typical case. In order to have smaller current ripple (to improve efficiency and minimize output voltage ripple), larger inductance will be required. If inductor ripple current needs to be less than 40% of the average input curr ent, then Where duty cycle can be estimated as Then Therefore, the inductance can be calculated as Where, fS is the switching frequency of the boost converter. IN MAXOUTOUT MAXIN V IVI IN MAXOUTOUTSIN L V IV L TDVI %40 OUT INOUT V VVD −=  −= IN MAXOUTOUT OUT SINOUTIN L V IV VL TVVVI %40)( SMAXOUTOUT INOUTIN fIV VVVL  − %40 )( 

Table 28. Recommended Inductor Part Numbers terminals should be connected together on the PCB top layer and on the bottom layer GND plane. Figure 8. Recommended PCB Layout

t KTZ8866 January 2022 - Revision 04b Page 37 of 37 Company Confidential Packaging Information WLCSP47-28 (1.730mm x 2.920mm x 0.620mm) 0.400mm Typ. 0.400mm Typ. 28x 0.27mm Ø ±0.027mm 1.730mm ±0.050mm 2.920mm ±0.050mm 0.215mm ±0.022mm 0.620mm ±0.045mm 0.025mm ±0.003mm Bottom ViewSide ViewTop View Top Side Die Coating A1 Corner Recommended Footprint 0.40mm 0.40mm 1.20mm 2.40mm 0.32mm Solder Mask Opening 0.22mm Copper Pad Diameter (NSMD Pad Type) Kinetic Technologies cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Kinetic Technologies product. No intellectual property or circuit patent licenses are implied. Kinetic Technologies reserves the right to change the circuitry and specifications without notice at any time.