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XC9133 Series
Step-Up DC/DC Converter-LED Backlight Driver
ETR0413-002
GENERAL DESCRIPTION
The XC9133 series is a fixed frequency, constant current step-up DC/DC converter which is optimized for LED backlight applications in mobile phones, PDAs and digital cameras. Output voltage of up to 17.5V is possible so that four white LEDs can be driven in series. Since the LED current is set by only one external resistor, all white LEDs placed in series can be turned on at the same time. The new DC/DC Converter is also able to drive a network of two parallel banks of three LEDs. LED dimming is controlled by adjusting the duty cycle of a PWM signal (10kHz Max.) applied to the CE pin. Efficiency is high with a 0.2V low feedback reference voltage ensuring the RLED losses are minimal. In addition, an internal MOSFET with a low RDSON of 2.4 is used. A low profile and small board area solution can be achieved using a chip inductor and a small ceramic output capacitor CL=0.22 F as a result of the high 1MHz switching frequency. If white LEDs are opened or damaged, the detector built in the Lx pin causes the IC to stop oscillating, preventing excessive increase of the output voltage.
APPLICATIONS
For White LED drivers Mobile phones PDAs Digital cameras
FEATURES
Input Voltage Range : 2.5V ~ 6.0V Output Voltage Range : Up to 17.5V externally set-up Reference voltage 0.2V +5% Oscillation Frequency : 1.0MHz 20% ON Resistance : 2.4 High Efficiency : 85% 3 white LEDs in series VIN=3.6V, ILED=20mA Control : PWM control Stand-by Current : ISTB=1.0 A (MAX.) Output Capacitor : 0.22 F, ceramic Lx Limit Current : 360mA TYP. Lx Overvoltage Limit : 19V (TYP.) Packages : SOT-25 USP-6C (under development)
TYPICAL APPLICATION CIRCUIT
TYPICAL PERFORMANCE CHARACTERISTICS
XC9133B02A Series
LEDNSCW100 x 3 SBDXBS053V15R,CLTMK316J224KF
100 Efficiency : EFFI (%) 90 80 70 60 50 40 30 20 10 0 0
LVLF3010S
NR3015
VIN=3.0V
5
10
15
20
25
30
LED Currrent : ILED (mA)
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XC9133 Series
PIN CONFIGURATION
*The dissipation pad should be left open. If the circuit needs to be connected to other pin, it should be connected to the VSS pin.
SOT-25 (TOP VIEW)
USP-6C (BOTTOM VIEW) under development
PIN ASSIGNMENT
PIN NUMBER USP-6C SOT-25 (under development) 1 2 3 4 5 2 3 1 6 4 5 PIN NAME Lx VSS FB CE VIN NC FUNCTION Switch Ground Voltage Feedback Chip Enable Power Input No Connection
CE PIN FUNCTION
CE PIN H L OPERATIONAL STATE Operation Shut-down
PRODUCT CLASSIFICATION
Ordering Information
XC9133 DESIGNATOR (*1)
DESCRIPTION Lx Overvoltage Limit FB Voltage Oscillation Frequency Packages Taping Type
(*2)
SYMBOL B 02 A MR MR-G ER Available 0.2V 1MHz SOT-25
DESCRIPTION
SOT-25 (Halogen & Antimony free) USP-6C (under development)
(*1) (*2)
The "-G" suffix indicates that the products are Halogen and Antimony free as well as being fully RoHS compliant. The device orientation is fixed in its embossed tape pocket. For reverse orientation, please contact your local Torex sales office or representative. (Standard orientation: R- , Reverse orientation: L- )
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XC9133
Series
BLOCK DIAGRAMS
XC9133B02A
ABSOLUTE MAXIMUM RATINGS
Ta = 25 PARAMETER VIN Pin Voltage Lx Pin Voltage FB Pin Voltage CE Pin Voltage Lx Pin Current SOT-25 Power Dissipation USP-6C (under development) Pd Topr Tstg SYMBOL VIN VLx VFB VCE ILx RATINGS VSS - 0.3 ~ 7.0 VSS - 0.3 ~ 22.0 VSS - 0.3 ~ 7.0 VSS - 0.3 ~ 7.0 1000 250 100 - 40 ~ + 85 - 55 ~ +125 mW UNITS V V V V mA
Operating Temperature Range Storage Temperature Range
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XC9133 Series
ELECTRICAL CHARACTERISTICS
XC9133B02AMR
PARAMETER FB Voltage Output Voltage Range Input Voltage Range Supply Current 1 Supply Current 2 Stand-by Current Oscillation Frequency Maximum Duty Cycle Efficiency (*1) Current Limit Lx Overvoltage Limit Lx ON Resistance Lx Leakage Current CE High Voltage CE Low Voltage CE High Current CE Low Current FB High Current FB Low Current
NOTE: *Test circuit *Test circuit *Test circuit *Test circuit
Ta = 25 SYMBOL VFB VOUTSET VIN IDD1 IDD2 ISTB fOSC MAXDTY EFFI ILIM VLxOVL RSWON ILxL VCEH VCEL ICEH ICEL IFBH IFBL CONDITIONS MIN. 0.19 VIN 2.5 0.8 86 260 18.0 0.65 VSS -0.1 -0.1 -0.1 -0.1 TYP. 0.20 420 60 0 1.0 92 85 360 19.0 2.4 0.0 MAX. 0.21 17.5 6.0 720 140 1.0 1.2 98 460 22.0 UNIT. V V V A A A MHz % % mA V
CIRCUIT
VIN=VLx, FB=0.4V CE=0V, VLx=5.0V
When connected to ext. components, VIN=3.6V, RLED=20 When connected to ext. components, VIN=3.6V Voltage which Lx pin voltage holding "High" level 2.5V VIN VIN=3.6V, VLx=0.4V (*3) Same as ISTB CE applied voltage when Lx starts oscillation CE applied voltage which Lx pin voltage holding "High" level Same as IDD2 Same as ISTB Same as IDD2 Same as ISTB
1.0 6.0 0.2 0.1 0.1 0.1 0.1
A V V A A A A
: Unless otherwise stated, VIN=3.0V, VCE=3.0V, RLED=10 : Unless otherwise stated, VIN=3.0V, VCE=3.0V, VFB=0.0V, VPULL=5.0V, RPULL=100 : Unless otherwise stated, VIN=3.0V, VCE=3.0V, VFB=0.0V : Unless otherwise stated, VCE=3.0V, VPULL=5.0V
*1: The duty cycle is forcibly reduced when maximum duty cycle periods are repeated. *2: LED NSPW310BS x 3, EFFI = {[(output voltage) x (output current)] / [(input voltage) x (input current)]} x 100 *3: VPULL is adjusted to make VLX 0.4V when the driver transistor is turned on.
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XC9133
Series
TYPICAL APPLICATION CIRCUITS
XC9133B02A
EXTERNAL COMPONENTS
SYMBOL L SBD (*1) CIN CL (*3) VALUE 22 H 4.7 F 0.22 F PART NUMBER VLF3010A-220MR XBS053V15R (*2) MA2Z720 JMK107BJ475MA-B TMK107BJ224KA-B MANUFACTURER TDK TOREX PANASONIC TAIYO YUDEN TAIYO YUDEN
NOTE: *1: Please use a Schottky barrier diode (SBD) with a low junction capacitance. *2: For using the XBS053V15R with four white LEDs in series, please be noted with a direct reverse voltage (VR=20V) and a repetitive peak reverse voltage (VRM=30V). *3: Use ceramic capacitors processing a low temperature coefficient.
OPERATIONAL EXPLANATION
The series consists of a reference voltage source, ramp wave circuit, error amplifier, PWM comparator, phase compensation circuit, Lx overvoltage limit circuit, N-channel MOS driver transistor, current limiter circuit and others. Phase compensation is performed on the resulting error amplifier output, to input a signal to the PWM comparator to determine the turn-on time during switching. The PWM comparator compares, in terms of voltage level, the signal from the error amplifier with the ramp wave from the ramp wave circuit, and delivers the resulting output to the N-channel MOS driver transistor to cause the Lx pin to output a switching duty cycle. This process is continuously performed to ensure stable output voltage. The current feedback circuit detects the N-channel MOS driver transistor's current for each switching operation, and modulates the error amplifier output signal. This enables a stable feedback loop even when a low ESR capacitor, such as a ceramic capacitor, is used, ensuring stable output voltage. The reference voltage source provides the reference voltage to ensure stable output voltage of the IC. The ramp wave circuit determines switching frequency. The 1MHz (TYP.) of frequency is fixed internally. Clock pulses generated in this circuit are used to produce ramp waveforms needed for PWM operation. The error amplifier is designed to monitor output voltage. The amplifier compares the reference voltage with the FB pin voltage. When a feed-back voltage becomes lower than the reference voltage, an output voltage of the error amplifier is increased. Gain and frequency characteristics of the error amplifier output are fixed internally as an optimize signal.
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XC9133 Series
OPERATIONAL EXPLANATIONS (Continued)
The current limit circuit of the XC9133 series monitors the current flowing through the N-channel MOS driver transistor connected to the Lx pin, and features a combination of the constant-current type current limit mode and the duty cycle limit of the next pulse. 1When the driver current is greater than a specific levels, the constant-current type current limit function operates to turn off the pulses from the Lx pin at any given timing. 2The IC controls the next pulse to be smaller than the first pulse.
Current Limit Current Limit
The current will be off when the coil current reached the value of the constant current limit.
Limit some duty pulses after the limit.
XC9133 series' Lx overvoltage limit circuit monitors the Lx pin voltage. When the Lx pin voltage exceeds than 19V (TYP.), the IC performs the function of latching the OFF state of the driver transistor, and goes into operation suspension mode. In suspension mode, operations can be resumed by restoring power to the VIN pin. The suspension mode does not mean a complete shutdown, but a state in which pulse output is suspended; therefore, the internal circuitry remains in operation. The XC9133 series' maximum duty cycle limit circuit monitors the duty cycle. When the maximum duty cycle is repeated for a certain time, the IC controls the error amplifier output so that the duty cycle of the next pulse becomes smaller than that of the first pulse. The operation of the XC9133 series will enter into the shut down mode when a low level signal is input to the CE pin. During the shut down mode, the supply current is 0 A (TYP.), with high impedance at the Lx pin. The IC starts its operation with a high level signal to the CE pin. The input to the CE/MODE pin is a CMOS input and the sink current is 0 A (TYP.). 100 s after disable, the IC goes into suspension mode and supply current is minimal. After this, the IC will be in stand-by mode and the supply current will be 0 A (TYP.).
NOTES ON USE
Please connect the anode of a Schottky barrier diode and an inductor to the Lx pin. The reference voltage is 200mV (TYP.). A resistor (RLED) should be connected to the FB pin for setting the cathode of LEDs and a constant current value. The resistance value can be calculated by the following equation. RLED=0.2 / ILED ILED=Setting constant current value Typical example: ILED 5mA 10mA RLED 40 20 ILED 13.3mA 20mA RLED 15 10
An ENABLED state is reached when the CE voltage exceeds 0.65V and a DISABLED state when the CE Voltage falls below 0.2V. Please connect an inductor and an input by-pass capacitor (CIN) to the VIN pin.
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XC9133
Series
APPLICATION INFORMATION
1. Applying PWM signal to the CE pin The XC9133 repeats on/off operations by a PWM signal applied to the CE pin. The magnitude of LED current, ILED, when the diode is on, is determined by RLED. The magnitude is zero when the diode is off. The average of LED current is proportional to the positive duty ratio of the PWM signal. The frequency of the PWM signal can be controlled to the optimum value between 100Hz and 10kHz. With regard to the amplitude of the PWM signal, the high level should be higher than the "H" voltage of CE, VCEH, and the low level, lower than the "L" voltage of CE, VCEL.
10kHz, 3 series LED, ILED=20mA 10kHz, 4 series LED, ILED=20mA
20
s / div
20
s / div
1kHz, 3 series LED, ILED=20mA
1kHz, 4 series LED, ILED=20mA
200
s / div
200
s / div
2. Step-Wise Regulation of LED Current In some applications, it may be necessary to incorporate step-wise regulation of LED current, ILED. Step-wise regulation of LED illumination is achieved by connecting a switch element SW1 in parallel with RLED and in series with RLED1 and turning SW1 on and off, as shown below. Choose a resistance of RLED so that the minimum necessary current is gained when switch element SW1 is off. The resistance of RLED1 should be such that a desired increase of current passed through the LED is gained when the switch element is on.
Ex.) Current ILED = 5mA and 15mA RLED = 200mV / 5mA = 40 RLED1 = 200mV / (15mA - 5mA) = 20
Figure
Circuit using Step-wise Regulation of LED Current
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XC9133 Series
APPLICATION INFORMATION (Continued)
3. Using DC Voltage If in an application it is necessary to control the LED current by a variable DC voltage, illumination control of LED is achieved by connecting R1 and R2 and applying a direct-current voltage to R2, as shown below. When R1>>RLED, ILED which flows into LEDs can be calculated by the following equation;
ILED
ILED = (VREF - R1 / R2 (VDC - VREF)) / RLED VREF = 0.2V (TYP.) Ex.1) When R1 = 10k , R2 = 100k , RLED = 10 , In the range of 0.2V to 2.2V DC, ILED (LED current) varies between 20mA to 0mA.
VDC R2
XC9133 FB R1 RLED
Figure
Circuit using DC voltage
Ex.2) When R1 = 10k , R2 = 100k , R3 = 10k , C1 = 0.1F, RLED = 10, the average LED current will be 10mA by inputting a PWM signal of CE `H' level: 2.2V, CE 'L' level: 0V, duty cycle: 50%, oscillation frequency: 100Hz. As well as the way of dimming control by applying the PWM signal to the CE pin, the average LED current increases proportionally with the positive duty cycle of the PWM signal. Figure Circuit inputting a PWM signal to the FB pin
When the input voltage (VIN) is high, minimum illumination may occur even if the CE pin is in the disable state. If this happens, please connect a transistor to between the LED and the FB pin. By driving the CE signal in-phase and cutting the pass to current, the minimum illumination can be prevented.
L:22H VLF3010A VIN 3.6V (3.2V~6.0V) CL 0.22F (base) XP151A12A2 CE VSS FB RLED 10 20mA SBD XBS053V15R
CIN 4.7F
VIN
Lx
Figure
Circuit Prevent Emission Caused by White LEDs Leakage
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XC9133
Series
APPLICATION INFORMATION (Continued)
It is possible to illuminate three-series two parallel white LEDs, six in total, using an input voltage VIN 3.2V.
Figure
Circuit Illumination of Six in Total White LEDs
An LED current 65mA (MAX.) can be supplied to two white LEDs.
Figure
Circuit using a Flash
9/15
XC9133 Series
APPLICATION INFORMATION (Continued)
Supply source of the step-up circuit can be used separately from VIN pin.
Circuit example of separating supply source of the step-up circuit from VIN pin ( 3 LEDs) Note: Please input 2.5V~6V to the VIN pin when you use.
Circuit example of separating supply source of the step-up circuit from VIN pin ( 2 LEDs)
If white LEDs are opened or damaged, the FB pin is pulled down, so that the operating duty ratio reaches the maximum. Accordingly, the output voltage continues to increase, possibly causing the Lx pin voltage to exceed the absolute maximum rating of 22V. If white LEDs are opened or damaged, the detector built in the Lx pin causes the IC to stop oscillating, preventing excessive increase of the output voltage. However, the detector may detect an overvoltage if the Lx pin voltage exceeds 18V, which is the overvoltage limit, even when no LEDs are open. Therefore, care must be taken if four LEDs each having a forward voltage of 4.45V or more are connected in series. The XC9133 series has no soft-start circuit built-in in order to minimize delay at startup. The inrush current can reach up to the current limit ILIM. In some cases, overshoot can occur.
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XC9133
Series
APPLICATION INFORMATION (Continued)
1. In order to stabilize VIN's voltage level, we recommend that an input by-pass capacitor (CIN) be connected as close as possible to the VIN & VSS pins. 2. Please mount each external component as close to the IC as possible. 3. Wire external components as close to the IC as possible and use thick, short connecting traces to reduce the circuit impedance. 4. Make sure that the PCB GND traces are as thick as possible, as variations in ground potential caused by high ground currents at the time of switching may result in instability of the IC.
XC9133B Series Pattern Layout (SOT-25)
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XC9133 Series
TEST CIRCUITS
Circuit (XC9133B02A Series)
L:22uH SBD CDRH3D16 XBS053V15R
CIN VIN
4.7F (ceramic)
VIN
Lx CL
0.22F (ceramic)
CE VSS VCE
FB RLED V
Circuit
Circuit
Circuit
1. The measurement method of LX ON Resistance RSWON Using the circuit , Lx ON resistance can be measured by adjusting VPULL voltage to set Lx voltage VLX 0.4V when the driver transistor is ON. The oscilloscope is used for measuring the Lx voltage when the driver transistor is ON. RSWON = 0.4 / ((VPULL - 0.4) /10) 2. The measurement method of current limit ILIM Using the circuit , current limit ILIM can be calculated by the equation including VPULL voltage when FB voltage is decreased while VPULL voltage is adjusted and Lx voltage VLX when the driver transistor is ON. The oscilloscope is used for measuring the Lx voltage when the driver transistor is ON. ILIM = (VPULL - VLX) / RPULL RPULL 10
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XC9133
Series
PACKAGING INFORMATION
SOT-25
(unit : mm)
2.90.2 +0.1 0.4 -0.05
USP-6C (under development)
5
4
00.1
1
(0.95)
2
1.90.2
3
+0.1 0.15 -0.05
* Pin no. 1 is wider than other pins.
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XC9133 Series
MARKING RULE
SOT-25
Represents product series MARK
F
PRODUCT SERIES XC9133B02AD x
SOT-25 (TOP VIEW)
Represents Lx overvoltage limit MARK B Lx OVERVOLTAGE LIMIT Available PRODUCT SERIES XC9133B02AM x
Represents oscillation frequency MARK A OSCILLATION FREQUENCY 1MHz PRODUCT SERIES XC9133B02AM x
Represents production lot number 0 to 9 and A to Z, or inverted characters 0 to 9 and A to Z repeated. (G, I, J, O, Q, W excepted)
USP-6C (under development)
Represents product series MARK K Represents Lx overvoltage limit MARK USP-6C (TOP VIEW) B Lx OVERVOLTAGE LIMIT Available PRODUCT SERIES XC9133B02AD x PRODUCT SERIES XC9133B02AD x
Represents FB voltage MARK 0 2 FB VOLTAGE (V) 0.2 PRODUCT SERIES XC9133B02AD x
Represents oscillation frequency MARK A OSCILLATION FREQUENCY 1MHz PRODUCT SERIES XC9133 B02AD x
Represents production lot number 0 to 9 and A to Z repeated (G, I, J, O, Q, W excepted) * No character inversion used.
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XC9133
Series
1. The products and product specifications contained herein are subject to change without notice to improve performance characteristics. Consult us, or our representatives before use, to confirm that the information in this datasheet is up to date. 2. We assume no responsibility for any infringement of patents, patent rights, or other rights arising from the use of any information and circuitry in this datasheet. 3. Please ensure suitable shipping controls (including fail-safe designs and aging protection) are in force for equipment employing products listed in this datasheet. 4. The products in this datasheet are not developed, designed, or approved for use with such equipment whose failure of malfunction can be reasonably expected to directly endanger the life of, or cause significant injury to, the user. (e.g. Atomic energy; aerospace; transport; combustion and associated safety equipment thereof.) 5. Please use the products listed in this datasheet within the specified ranges. Should you wish to use the products under conditions exceeding the specifications, please consult us or our representatives. 6. We assume no responsibility for damage or loss due to abnormal use. 7. All rights reserved. No part of this datasheet may be copied or reproduced without the prior permission of TOREX SEMICONDUCTOR LTD.
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