XC9133 Series
ETR0413-002
Step-Up DC/DC Converter-LED Backlight Driver
■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 2.4Ω is used. A low profile and small board area solution can be achieved using a chip
inductor and a small ceramic output capacitor CL=0.22μF 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.
●For White LED drivers
●Mobile phones
●PDAs
●Digital cameras
■TYPICAL APPLICATION CIRCUIT
■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
: 2.4Ω
High Efficiency
: 85%
3 white LEDs in series
VIN=3.6V, ILED=20mA
Control
: PWM control
Stand-by Current
: ISTB=1.0μA (MAX.)
Output Capacitor
: 0.22μF, ceramic
Lx Limit Current
: 360mA（TYP.）
Lx Overvoltage Limit : 19V (TYP.)
Packages
: SOT-25
USP-6C (under development)
■TYPICAL PERFORMANCE
CHARACTERISTICS
●XC9133B02A Series
LED：NSCW100 x 3
SBD：XBS053V15R,CL：TMK316J224KF
100
Efficiency : EFFI (%)
■APPLICATIONS
L：VLF3010S
90
80
NR3015
70
60
50
40
30
20
10
0
VIN=3.0V
0
5
10
15
20
25
30
LED Currrent : ILED (mA)
1/15
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
FUNCTION
Lx
VSS
FB
CE
VIN
NC
Switch
Ground
Voltage Feedback
Chip Enable
Power Input
No Connection
■CE PIN FUNCTION
CE PIN
OPERATIONAL STATE
H
L
Operation
Shut-down
■PRODUCT CLASSIFICATION
●Ordering Information
XC9133①②③④⑤⑥-⑦(*1)
DESIGNATOR
DESCRIPTION
SYMBOL
①
Lx Overvoltage Limit
B
Available
②③
FB Voltage
02
0.2V
④
Oscillation Frequency
A
1MHz
⑤⑥-⑦
MR
Packages
Taping Type
(*2)
MR-G
ER
(*1)
(*2)
DESCRIPTION
SOT-25
SOT-25 (Halogen & Antimony free)
USP-6C (under development)
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: ⑤R-⑦, Reverse orientation: ⑤L-⑦)
2/15
XC9133
Series
■BLOCK DIAGRAMS
●XC9133B02A
■ ABSOLUTE MAXIMUM RATINGS
Ta = 25℃
PARAMETER
SYMBOL
RATINGS
UNITS
VIN Pin Voltage
VIN
VSS – 0.3 ~ 7.0
V
Lx Pin Voltage
VLx
VSS – 0.3 ~ 22.0
V
FB Pin Voltage
VFB
VSS – 0.3 ~ 7.0
V
CE Pin Voltage
VCE
VSS – 0.3 ~ 7.0
V
Lx Pin Current
ILx
1000
mA
SOT-25
Power Dissipation
USP-6C
(under development)
250
Pd
100
mW
Operating Temperature Range
Topr
- 40 ~ + 85
℃
Storage Temperature Range
Tstg
- 55 ~ +125
℃
3/15
XC9133 Series
■ELECTRICAL CHARACTERISTICS
●XC9133B02AMR
Ta = 25℃
PARAMETER
FB Voltage
Output Voltage Range
Input Voltage Range
Supply Current 1
Supply Current 2
Stand-by Current
Oscillation Frequency
Maximum Duty Cycle
SYMBOL
VFB
VOUTSET
VIN
IDD1
IDD2
ISTB
fOSC
MAXDTY
Efficiency (*1)
EFFI
Current Limit
ILIM
Lx Overvoltage Limit
VLxOVL
Lx ON Resistance
Lx Leakage Current
RSWON
ILxL
CE High Voltage
VCEH
CE Low Voltage
VCEL
CE High Current
CE Low Current
FB High Current
FB Low Current
ICEH
ICEL
IFBH
IFBL
NOTE:
*Test circuit
*Test circuit
*Test circuit
*Test circuit
CONDITIONS
VIN=VLx, FB=0.4V
CE=0V, VLx=5.0V
When connected to ext.
components, VIN=3.6V, RLED=20Ω
When connected to ext. components,
VIN=3.6V
Voltage which Lx pin voltage
holding ”High” level
VIN ≧ 2.5V
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
MIN.
0.19
VIN
2.5
0.8
86
TYP.
0.20
420
60
0
1.0
92
MAX.
0.21
17.5
6.0
720
140
1.0
1.2
98
UNIT.
V
V
V
μA
μA
μA
MHz
%
CIRCUIT
-
85
-
%
①
260
360
460
mA
④
18.0
19.0
22.0
V
②
-
2.4
0.0
1.0
Ω
μA
④
③
0.65
-
6.0
V
②
VSS
-
0.2
V
②
-0.1
-0.1
-0.1
-0.1
-
0.1
0.1
0.1
0.1
μA
μA
μA
μA
③
③
③
③
①: Unless otherwise stated, VIN=3.0V, VCE=3.0V, RLED=10Ω
②: Unless otherwise stated, VIN=3.0V, VCE=3.0V, VFB=0.0V, VPULL=5.0V, RPULL=100Ω
③: Unless otherwise stated, VIN=3.0V, VCE=3.0V, VFB=0.0V
④: 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.
4/15
①
①
①
②
③
③
②
②
XC9133
Series
■TYPICAL APPLICATION CIRCUITS
●XC9133B02A
■EXTERNAL COMPONENTS
SYMBOL
VALUE
PART NUMBER
MANUFACTURER
L
22μH
SBD (*1)
-
CIN
CL (*3)
4.7μF
0.22μF
VLF3010A-220MR
XBS053V15R (*2)
MA2Z720
JMK107BJ475MA-B
TMK107BJ224KA-B
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.
<Reference Voltage Source>
The reference voltage source provides the reference voltage to ensure stable output voltage of the IC.
<Ramp Wave Circuit>
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.
<Error Amplifier>
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.
5/15
XC9133 Series
■OPERATIONAL EXPLANATIONS (Continued)
<Current Limit>
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.
<Lx Overvoltage Limit Circuit>
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.
<Maximum Duty Cycle Limit>
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.
<CE Pin Function>
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 0μA (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
μA (TYP.). 100μs 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 0μA (TYP.).
■NOTES ON USE
<Lx (Pin 1): Switch Pin>
Please connect the anode of a Schottky barrier diode and an inductor to the Lx pin.
<FB (Pin 3): Voltage Feedback 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
40Ω
20Ω
ILED
13.3mA
20mA
RLED
15Ω
10Ω
<CE (Pin 4): Chip Enable Pin>
An ENABLED state is reached when the CE voltage exceeds 0.65V and a DISABLED state when the CE Voltage falls below
0.2V.
<VIN (Pin 5): Power Supply Pin>
Please connect an inductor and an input by-pass capacitor (CIN) to the VIN pin.
6/15
XC9133
Series
■APPLICATION INFORMATION
<Dimming Control>
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, 4 series LED, ILED=20mA
10kHz, 3 series LED, ILED=20mA
20μs / div
20μs / div
1kHz, 3 series LED, ILED=20mA
1kHz, 4 series LED, ILED=20mA
200μs / div
200μs / 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 Ω
RLED1 = 200mV / (15mA – 5mA) = 20 Ω
Figure
Circuit using Step-wise Regulation of LED Current
7/15
XC9133 Series
■APPLICATION INFORMATION (Continued)
<Dimming Control (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.)
XC9133
FB
Ex.1) When R1 = 10k Ω, R2 = 100k Ω, RLED = 10 Ω,
In the range of 0.2V to 2.2V DC, ILED
(LED current) varies between 20mA to 0mA.
R2
VDC
R1
RLED
Figure
Circuit using DC voltage
Ex.2) When R1 = 10k Ω, R2 = 100k Ω, R3 = 10k Ω,
C1 = 0.1μF, RLED = 10Ω, 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
<Prevent Emission Caused by White LEDs Leakage>
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.
SBD
XBS053V15R
L:22μH
VLF3010A
VIN
3.6V
(3.2V~6.0V)
CIN
4.7μF
VIN
Lx
XP151A12A2
CE
FB
VSS
Figure
8/15
CL
0.22μF
(base)
RLED
10Ω
20mA
Circuit Prevent Emission Caused by White LEDs Leakage
XC9133
Series
■APPLICATION INFORMATION (Continued)
<Illumination of Six in Total White LEDs>
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
<Use as Flash>
An LED current 65mA (MAX.) can be supplied to two white LEDs.
Figure
Circuit using a Flash
9/15
XC9133 Series
■APPLICATION INFORMATION (Continued)
<Separate Supply Source of the Step-up Circuit (VIN) from VIN Pin>
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)
Circuit example of separating supply source of
the step-up circuit from VIN pin ( 2 LEDs)
Note: Please input 2.5V~6V to the VIN pin when you use.
<LED Open-circuit Protection>
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.
<Startup Inrush Current>
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.
10/15
XC9133
Series
■APPLICATION INFORMATION (Continued)
<Instruction on Pattern Layout>
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)
11/15
XC9133 Series
■TEST CIRCUITS
●Circuit ① (XC9133B02A Series)
L:22uH
SBD
CDRH3D16 XBS053V15R
CIN
VIN
VIN
Lx
CE
FB
4.7μF
(ceramic)
CL
VSS
0.22μF
(ceramic)
RLED
V
VCE
●Circuit ②
●Circuit ③
●Circuit ④
1. The measurement method of LX ON Resistance RSWON
Using the circuit ④, 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 ④, 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＝10Ω
12/15
XC9133
Series
■PACKAGING INFORMATION
●SOT-25
●USP-6C (under development)
(unit : mm)
2.9±0.2
+0.1
0.4 -0.05
5
4
0～0.1
1
2
(0.95)
3
+0.1
0.15 -0.05
1.9±0.2
* Pin no. 1 is wider than other pins.
13/15
XC9133 Series
■ MARKING RULE
●SOT-25
①Represents product series
SOT-25
(TOP VIEW)
MARK
PRODUCT SERIES
F
XC9133B02AD x
②Represents Lx overvoltage limit
MARK
Lx OVERVOLTAGE LIMIT
PRODUCT SERIES
B
Available
XC9133B02AM x
MARK
OSCILLATION FREQUENCY
PRODUCT SERIES
A
1MHz
XC9133B02AM x
③Represents oscillation frequency
④Represents 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)
①Represents product series
MARK
PRODUCT SERIES
K
XC9133B02AD x
②Represents Lx overvoltage limit
USP-6C
(TOP VIEW)
MARK
Lx OVERVOLTAGE LIMIT
PRODUCT SERIES
B
Available
XC9133B02AD x
FB VOLTAGE (V)
PRODUCT SERIES
0.2
XC9133B02AD x
MARK
OSCILLATION FREQUENCY
PRODUCT SERIES
A
1MHz
XC9133 B02AD x
③④Represents FB voltage
MARK
③
④
0
2
⑤Represents oscillation frequency
⑥Represents production lot number
0 to 9 and A to Z repeated (G, I, J, O, Q, W excepted)
* No character inversion used.
14/15
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.
15/15