Download PDFKTD2801 KINETIC
Document overview
- Manufacturer or author: Provided By digicamel.com
- PDF pages: 18
Technical content
Features
Wide VIN input range: 2.7V to 5.5V Wide output range: up to 10 series LEDs Integrated 40V high current switch (0.52A limit) High efficiency boost converter (up to 85%) Highly integrated solution Integrated diode Internal compensation and soft start ExpressWireTM interface dual method dimming with single pin (CTRL) 256-step Serial dimming control High resolution PWM dimming High accuracy across full load range LED open-circuit (OVP) protection KTD2801 : 36V KTD2801A : 30V KTD2801B : 24V Low 200mV feedback voltage 1MHz High switching frequency Simple, small solution size < 1 µA shutdown current Small TDFN22-6 and Thin SOT23 package RoHS and Green compliant -40°C to +85°C Temperature Range
Applications
LED backlighting Mobile Phones, Handheld Devices Digital Photo Frames, Automotive Navigation Brief Description The KTD2801/A/B is a versatile constant current LED driver with a high efficiency DC-DC step up “boost” converter architecture. The low-side power MOSFET and high-side diode are integrated in the device, minimizing the total number of external components. Unique technology and high 0.52A current limit allow KTD2801 to drive up to 36V output (10 LEDs in series), or KTD2801A 30V output (8 LEDs in series ) or KTD2801B 24V output ( 6 LEDs). Alternatively, the KTD2810 can deliver 40mA total current for two parallel strings of up to 6 series LED s. It can also maximize the current capability while achieving high conversion efficiency. Th e optimized 1MHz switching frequency results in small external component size. The driver is equipped with an internal decoder that allows digital FB control dimming for 256-step ( 8-bit) current programming and can also be used for PWM dimming with a one-line control signal. Various protection features are built into the KTD2801/A/B, including cycle-by-cycle input current limit protection, LED open-circuit (output over voltage) protection and thermal shutdown protection. The leakage current in shutdown mode is less than 1µA. The device is available in a RoHS compliant 6-lead TDFN22 package and 6-lead Thin SOT-23 package Typical Application VIN LX Up to 10 LEDs in series or up to 2P6S VIN 2.7V to 5.5V Brightness Control: ExpressWireTM or PWM dimming CTRL VOUT GND CIN 10µF COUT 0.47µF L 22µH FB 10Ω 36V/30V/24V Step-Up LED Driver with Internal Diode and Serial Control
April 2017 – Revision 04b Page 2 Company Confidential Pin Descriptions Pin # Name Function TDFN22-6 TSOT-23-6 1 4 CTRL IC control pin. Can be used to enable/disable the IC, as well as to program the output current using ExpressWire Control or PWM dimming. 2 6 VIN Input supply pin for the IC 3 5 VOUT Output voltage pin 4 3 FB Feedback voltage pin 5 2 GND Converter/IC ground 6 1 LX Switching node of the step-up converter MC - MC Metal chassis. Connect to ground for electrical and thermal usage. (TDFN22-6 PKG only) TDFN22-6 PKG (Top View) TSOT-23-6 PKG (Top View) CTRL VIN VOUT LX GND FB MC LX GND FB VIN VOUT CTRL
April 2017 – Revision 04b Page 3 Company Confidential Absolute Maximum Ratings1 (TA=25C unless otherwise noted) Symbol Description Value Units VIN Input voltage -0.3 to 6.0 V LX, VOUT High voltage nodes KTD2801 -0.3 to 40 V KTD2801A -0.3 to 34 KTD2801B -0.3 to 28 FB, CTRL Other pins -0.3 to VIN+0.3 V TJ 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 Thermal Capabilities Symbol Description Value Units TDFN22-6 θJA Thermal Resistance – Junction to Ambient2 65 C/W PD Maximum Power Dissipation at TA ≤ 25C 1.54 W ΔPD/C Derating Factor Above TA = 25C -15.4 mW/C TSOT23-6 θJA Thermal Resistance – Junction to Ambient2 190 C/W PD Maximum Power Dissipation at TA ≤ 25C 0.526 W ΔPD/C Derating Factor Above TA = 25C -1.9 mW/C
Ordering Information
(nominal) Marking3 Operating Temperature Package KTD2801ECD-TR 36V FFYYZ -40°C to +85°C TDFN22-6 KTD2801AECD-TR 30V FUYYZ -40°C to +85°C TDFN22-6 KTD2801BECD-TR 24V FGYYZ -40°C to +85°C TDFN22-6 KTD2801EHD-TR 36V FFYYZ -40°C to +85°C TSOT23-6 KTD2801AEHD-TR 30V FUYYZ -40°C to +85°C TSOT23-6 KTD2801BEHD-TR 24V FGYYZ -40°C to +85°C TSOT23-6 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. “YYZ” is the date code and assembly code.
April 2017 – Revision 04b Page 4 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 (25C). 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 2.5 2.65 V UVLOHYST UVLO hysteresis 0.15 V IQ IC standby current Not switching 0.28 0.5 mA IC operating current Switching 0.7 1.65 mA ISHDN VIN pin shutdown current CTRL = GND 0.1 1.0 A Step-Up Converter VFB FB pin accuracy 184 200 216 mV VFB_DATA FB pin accuracy at Data = 26 14.3 20.3 26.3 mV IFB FB pin bias current 0.1 A RDS(ON) NMOS on-resistance TA = 25°C 0.6 Ω VD Internal diode forward voltage 100mA 0.9 V ILX LX pin leakage current 1 A ILIM Peak NMOS current limit 520 mA IINRUSH-SU Peak Inductor Current During Startup KTD2801, VIN = 3.6V, 10 LEDs, ILED = 20mA, L = 10µH, COUT = 0.47µF 400 mA IINRUSH-OL Peak Inductor Current During Open-Load Condition KTD2801, VIN = 3.6V, L = 10µH, COUT = 0.47µF, VOVP = 36V 450 mA FSW Oscillator frequency 1.0 MHz Dmax Maximum duty cycle 92 95 % OVP Over voltage threshold Measured at VOUT pin KTD2801 36 V KTD2801A 30.2 V KTD2801B 24.4 V 4. The KTD2801 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.
April 2017 – Revision 04b Page 5 Company Confidential Electrical Characteristics Continued5 Symbol Description Conditions Min Typ Max Units Control VTH-L CTRL logic low threshold 0.4 V VTH-H CTRL logic high threshold 1.4 V RCTRL CTRL pull down resistor 300 k toff CTRL low pulse width to shutdown CTRL high to low 2.5 ms tEW_DET ExpressWire detection time6 260 s tEW_DELAY ExpressWire detection delay time 140 s tEW_WIN ExpressWire detection window time 1 ms tDS Start time of programming data 2 s tEOD_H End of data high time 350 s tEOD_L End of data low time 2 64 s tH_LB High time low bit Logic 0 2 64 s tL_LB Low time low bit Logic 0 2 x tH_LB 128 s tH_HB High time high bit Logic 1 2 x tL_HB 128 s tL_HB Low time high bit Logic 1 2 64 s fDIM Recommended PWM dimming frequency 5 100 kHz DDIM PWM dimming duty cycle resolution fDIM = 20kHz 2 % fDIM = 30kHz 3 % TJ-TH IC junction thermal shutdown threshold 150 C IC junction thermal shutdown hysteresis 15 C 5. The KTD2801 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. 6. To select ExpressWire programming, the CTRL pin must be low for more than tEW_DET during tEW_WIN.
April 2017 – Revision 04b Page 6 Company Confidential Typical Characteristics VIN = 3.6V, L = 22H (Coilcraft LPS4018-223), CIN = 10F, COUT = 0.47F with 8 LEDs in series at 20mA, TAMB = 25°C, unless otherwise specified. Efficiency vs. Input Voltage Efficiency vs. LED Current Efficiency vs. Input Voltage (Iout = 40mA, 2P6S LEDs) CTRL Logic Threshold Voltage Quiescent Current (non-switching) Operating Current (switching) Efficiency (%) Input Voltage (V) 8LEDs 10LEDs 6LEDs 100 0 2 4 6 8 10 12 14 16 18 20 Efficiency (%) LED Current (mA)
8 LEDs
10 LEDs
Efficiency (%) Input Voltage (V) 0.6 0.7 0.8 0.9 1.0 1.1 Vth (V) Input Voltage (V) Vth-high Vth-low 0.2 0.3 0.4 0.5 0.6 0.7 Quiescent Current (mA) Input Voltage (V) 0.4 0.6 0.8 1.0 1.2 1.4 Quiescent Current (mA) Input Voltage (V)
April 2017 – Revision 04b Page 7 Company Confidential Typical Characteristics (continued) VIN = 3.6V, L = 22H, CIN = 10F, COUT = 0.47F with 8 LEDs in series at 20mA, TAMB = 25°C, unless otherwise specified. Soft Start Turn On Turn Off Steady State Switching Turn On with LED Open (OVP) PWM Dimming (10kHz, 50% duty cycle) PWM Dimming Linearity (20kHz) 100 0 25 50 75 100 LED Current Ratio (%) PWM Duty Cycle (%)
April 2017 – Revision 04b Page 8 Company Confidential Typical Characteristics (continued) VIN = 3.6V, L = 22H, CIN = 10F, COUT = 0.47F with 8 LEDs in series at 20mA, TAMB = 25°C, unless otherwise specified. Switching Frequency 1.00 1.02 1.04 1.06 1.08 1.10 Frequency (MHz) Input Voltage (V)
April 2017 – Revision 04b Page 9 Company Confidential Functional Block Diagram Functional Description The KTD28 01/A/B uses a constant -frequency current -mode boost converter architecture to control the LED current by regulating the feedback voltage. Please refer to the functional block diagram above for an explanation of the device operation. At the beginning of each switching cycle, the internal power MOSFET turns on between the LX node and GND. A slope compensation ramp is added to the output of the current sense amplifier and the result is fed into the positive input of the comparator (COMP). When this voltage goes above the output voltage of the error amplifier (gM), the power MOSFET is turned off. The voltage at the output of the g M block amplifies the difference between the reference voltage and the feedback voltage (FB), so that FB voltage can be regulated to the reference voltage. The driver has built-in soft-start to limit the inrush current during startup and to limit the amount of overshoot on the output. Protection features in the KTD28 01 include over-voltage protection (O VP), cycle-by-cycle current limit protection and thermal shutdown. OVP protects in the event where an LED fails open, which forces the feedback voltage to zero. This causes the boost converter to operate in maximum duty cycle mode, ramping up the output voltage. Switching will stop when the output reaches the OVP threshold. The OVP feature protects the IC from damaging itself by exceeding the voltage rating on LX/VOUT pins. The control interface can be used for either PWM dimming or ExpressWireTM single-wire control. In ExpressWire mode, it accepts a data set into the CTRL pin to program the reference voltage. The data contains 8 bits, yielding 256 different current levels. In PWM dimming mode, PWM pulse is provided at CTRL pin to program the reference voltage according to the duty cycle of the PWM signal, so that the LED current is proportional to the PWM duty cycle. The simplest control method is accomplished by toggling CTRL between high and low to program the output current between IMAX and 0mA. IMAX is set by the resistor connected between FB and GND. Please see LED Maximum Current Setting section in this document to determine the proper resistor value. The KTD2801 enters shutdown mode whenever the CTRL input pin is pulled low for more than 2.5ms. Over voltage protection PWM Control and Gate Drive LX Voltage Reference 200mV CTRL FB VIN GND Oscillator Ramp Generator COMP gM VOUT Current Sense Σ Current Sense Thermal Shutdown VIN Current LimitInput Logic and Low Pass Filter Shutdown Delay
selected when the IC is enabled. By default, the dimming mode is PWM dimming. Figure 1. Dimming Mode Detection Pulses
- After the IC is powered up, CTRL’s 1st pulse high width (ExpressWire detection delay time) tEW_DELAY
should be greater than 140μs.
- CTRL’s 1st pulse low width (ExpressWire detection time) tEW_DET should be greater than 260μs.
- The programming pulses should be started within the ExpressWire detection window tEW_WIN, which is
1ms. Otherwise the default setting or previous stored setting will be used to set the reference voltage.
Table 1. The default step is full scale when the device is first enabled (VFB = 200 mV). The programmed reference Table 1. ExpressWireTM Interface – FB Voltage Programming Table
for acknowledge condition of data bit. shows the ExpressWireTM interface protocol. The Low Bit(0) and High Bit(1) is based on a time detection algorithms between tLOW and tHIGH. The tL_LB is low time of the Low Bit(0) and the tH_LB is high time of the Low Bit(0). The tL_HB is low time of the High Bit(1) and the tH_HB is high time of the High Bit(1). Figure 2. ExpressWireTM Interface – bit Coding Time explanation of the interface protocol. Figure 3. ExpressWireTM Interface Protocol Overview Table 2. CTRL Data Bit Table
6 D6 DATA BIT 6
5 D5 DATA BIT 5
4 D4 DATA BIT 4
3 D3 DATA BIT 3
2 D2 DATA BIT 2
1 D1 DATA BIT 1
Table 3. CTRL – Disable Control Figure 4. ExpressWireTM Interface – Set to Data Register Overview recommended. The formula and table for R1 selection are shown below. Table 4. Current Setting Resister (1%Values)
April 2017 – Revision 04b Page 14 Company Confidential
Application Information
A 10µH or 22µH inductor is recommended for the typical application. If high efficiency is a critical requirement, a low DCR inductor should be selected. The inductor’s saturation current rating should also exceed the peak input current. Table 5. Recommended Inductor Part Numbers allowed for 10-series LED applications. Table 6. Recommended Ceramic Capacitor Vendors also exceed the target output voltage. Table 7. Recommended Schottky Diode Part Numbers
a sensitive node and it should be kept separate from the LX switching node in the PCB layout. Figure 7. Recommended PCB Layout for TDFN22-6 Package
April 2017 – Revision 04b Page 17 Company Confidential Packaging Information TDFN22-6 Recommended Footprint D E L A Top View Bottom View Side View b Seating Plane e 5 6 3 2 1 TQFN22 (KTD2500) 2.50 1.65 * Dimensions are in millimeters. 0.35 0.65 0.58 1.0 1.35 Dimension mm Min. Typ. Max. A 0.70 0.75 0.80 A3 0.2BSC b 0.25 0.30 0.35 D 1.90 2.00 2.10 D2 1.40 1.50 1.60 E 1.90 2.00 2.10 E2 0.80 0.90 1.00 e 0.65BSC L 0.20 0.25 0.30
April 2017 – Revision 04b Page 18 Company Confidential TSOT23-6 Recommended Footprint Kinetic Technologies cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Kineti c Technologies product. No intellectual property or circuit patent licenses are implied. Kinetic Technologies rese rves the right to change the circuitry and specifications without notice at any time. Top View End ViewSide View e b D E1 E A1 A θ C L 3.84 * Dimensions are in millimeters. 0.62 0.95 1.22 1.40 Dimension mm Min. Typ. Max. A 0.60 0.85 1.10 A1 0.00 0.05 0.10 b 0.30 0.40 0.50 c 0.10 0.15 0.20 D 2.70 2.90 3.10 E 2.60 2.80 3.00 E1 1.40 1.60 1.80 e 0.95BSC e1 1.9BSC L 0.30 0.60 θ 4° 12°