XC9133 Series
ETR0413-003a
Step-Up DC/DC Converter-LED Backlight Driver
■GENERAL DESCRIPTIO N
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 ensur ing the R
MOSF ET 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 C
If white LEDs are opened or damaged, the detector built in the Lx pin causes the IC to stop oscillating, pr eventi ng e xces sive
increase of the output voltage.
■APPLICATIONS
●For White LED drivers
●Mobile phones
●PDAs
●Digital cameras
■TYPICAL APPLICATION CIRCUIT
L=0.22μF as a result of the high 1MHz switching frequency.
■FEATURES
Input Voltage Range : 2.5V ~ 6.0V
Output Voltage Range : Up to 17.5V externally set-up
Reference voltage 0.2V +
Oscillation Frequency : 1.0MHz±20%
ON Resistance : 2.4Ω
High Efficiency : 85%
3 white LEDs in series
V
Control : PWM control
Stand-by Current : I
Output Capacitor : 0.22μF, ceramic
Lx Limit Current : 360mA（TYP.）
Lx Overvoltage Limit : 19V (TYP.)
Operating Ambient Temperature
Packages : SOT-25
Environmentally Friendly : EU RoHS Compliant, Pb Free
■TYPICAL PERFORMANCE
100
90
80
70
60
50
40
30
Efficiency : EFFI (%)
20
10
LED losses are minimal. In addition, an internal
=3.6V, I
IN
=1.0μA (MAX.)
STB
LED
=20mA
: -40℃～+85℃
CHARACTERISTICS
●XC9133B02A Series
LED：NSCW100 x 3
SBD：XBS053V15R,C
L：VLF3010S
NR3015
0
0 5 10 15 20 25 30
LED Currrent : ILED (mA)
TMK316J224KF
：
L
VIN=3.0V
5%
1/15
g
XC9133 Series
■PIN CONFIGURATION
■PIN ASSIGNMENT
■CE PIN FUNCTION
■PRODUCT CLASSIFICATION
●Orderin
SOT-25 (TOP VIEW)
PIN NUMBER
SOT-25
1 Lx Switch
2 VSS Ground
3 FB Voltage Feedback
4 CE Chip Enable
5 VIN Power Input
CE PIN OPERATIONAL STATE
H Operation
L Shut-down
Information
XC9133①②③④⑤⑥-⑦
DESIGNATOR ITEM SYMBOL DESCRIPTION
① Lx Overvoltage Limit B Available
PIN NAME FUNCTION
②③ FB Voltage 02 0.2V
④ Oscillation Frequency A 1MHz
⑤⑥-⑦
(*1)
The “-G” suffix denotes Halogen and Antimony free as well as being fully RoHS compliant.
(*1)
Package (Order Unit)
MR SOT-25 (3,000/Reel)
MR-G SOT-25 (3,000/Reel)
2/15
A
■BLOCK DIAGRAMS
●XC9133B02A
■
BSOLUTE MAXIMUM RATINGS
PARAMETER SYMBOL RATINGS UNITS
VIN Pin Voltage VIN V
Lx Pin Voltage VLx V
FB Pin Voltage VFB V
CE Pin Voltage VCE V
Lx Pin Current ILx 1000 mA
Power Dissipation Pd 250 mW
Operating Ambient Temperature Topr - 40 ~ + 85
Storage Temperature Tstg - 55 ~ +125
Ta = 25℃
– 0.3 ~ 7.0 V
SS
– 0.3 ~ 22.0 V
SS
– 0.3 ~ 7.0 V
SS
– 0.3 ~ 7.0 V
SS
℃
℃
XC9133
Series
3/15
XC9133 Series
■ELECTRICAL CHARACTERISTICS
●XC9133B02AMR
PARAMETER SYMBOL CONDITIONS MIN. TYP. MAX. UNIT . CIRCUIT
FB Voltage VFB 0.19 0.20 0.21 V ①
Output Voltage Range V
Input Voltage Range VIN 2.5 - 6.0 V ①
Supply Current 1 I
Supply Current 2 I
Stand-by Current I
Oscillation Frequency
(*1)
f
Maximum Duty Cycle MAXDTY 86 92 98 % ②
Efficiency
(*2)
EFFI
Current Limit I
Lx Overvoltage Limit V
Lx ON Resistance R
Lx Leakage Current I
CE High Voltage V
CE Low Voltage V
CE High Current I
CE Low Current I
FB High Current I
FB Low Current I
NOTE: *Test circuit ①: Unless otherwise stated, VIN=3.0V, VCE=3.0V, R
*Test circuit ②: Unless otherwise stated, V
*Test circuit ③: Unless otherwise stated, V
*Test circuit ④: Unless otherwise stated, V
(*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)
: V
is adjusted to make VLX 0.4V when the driver transistor is turned on.
PULL
VIN - 17.5 V ①
OUTSET
- 420 720 μA ②
DD1
VIN=VLx, FB=0.4V - 60 140 μA ③
DD2
CE=0V, VLx=5.0V - 0 1.0 μA ③
STB
0.8 1.0 1.2 MHz ②
OSC
LIM
When connected to ext.
components, V
When connected to ext. components,
=3.6V
V
IN
=3.6V, R
IN
LED
=20Ω
- 85 - % ①
260 360 460 mA ④
Voltage which Lx pin voltage
LxOVL
SWON
LxL
CEH
CEL
CEH
CEL
FBH
FBL
holding ”High” level
≧ 2.5V
V
IN
VIN=3.6V, VLx=0.4V
Same as I
CE applied voltage when Lx starts
oscillation
CE applied voltage which Lx pin
voltage holding “High” level
Same as I
Same as I
Same as I
Same as I
(*3)
- 2.4 Ω ④
- 0.0 1.0 μA ③
STB
-0.1 - 0.1 μA ③
DD2
-0.1 - 0.1 μA ③
STB
-0.1 - 0.1 μA ③
DD2
-0.1 - 0.1 μA ③
STB
=10Ω
=3.0V, VCE=3.0V, VFB=0.0V, V
IN
=3.0V, VCE=3.0V, VFB=0.0V
IN
=3.0V, V
CE
PULL
LED
=5.0V
18.0 19.0 22.0 V ②
0.65 - 6.0 V ②
VSS - 0.2 V ②
PULL
=5.0V, R
PULL
=100Ω
Ta = 25℃
4/15
XC9133
Series
■TYPICAL APPLICATION CIRCUITS
●XC9133B02A
■EXTERNAL COMPONENTS
SYMBOL VALUE PART NUMBER MANUFACTURER
L 22μH VLF3010A-220MR TDK
SBD
(*1)
-
XBS053V15R
MA2Z720 PANASONIC
CIN 4.7μF JMK107BJ475MA-B TAIYO YUDEN
(*3)
CL
0.22μF TMK107BJ224KA-B 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 (V
repetitive peak reverse voltage (V
*3: Use ceramic capacitors processing a low temperature coefficient.
RM=30V).
■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 outp ut, 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 continuousl y 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. T his enables a stable feedback loop ev en 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 PW M 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.
(*2)
TOREX
R=20V) and a
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 functio n operates to
6/15
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 V
IN 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 moni tors the dut y c ycle. When the maximum dut y cycle is repe ated
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 do wn 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 impeda nce 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.).
XC9133
Series
■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:
<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.
1. For temporary, transitional voltage drop or voltage rising phenomenon, the IC is liable to malfunction should the ratings be exceeded.
2. Torex places an importance on improving our products and their reliability.
We request that users incorporate fail-safe designs and post-aging protection treatment when using Torex products in their systems.
I
R
LED
I
LED
R
LED
LED
5mA 40Ω 13.3mA 15Ω
10mA 20Ω 20mA 10Ω
7/15
g
A
XC9133 Series
■
PPLICATION INFORMATION
<Dimming Control>
1. Applying PWM signal to the CE pin
The XC9133 repeats on/off operations by a PWM signal applied to the C E pin. The magn itude of LED current, ILED,
when the diode is on, is determined by R
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, V
than the "L" volta
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 R
turning SW1 on and off, as shown below. Choose a resistance of R
when switch element SW1 is off. The resistance of R
through the LED is gained when the switch element is on.
Ex.) Current ILED = 5mA and 15mA
R
LED = 200mV / 5mA = 40
R
LED1 = 200mV / (15mA – 5mA) = 20
e of CE, VCEL.
10kHz, 3 series LED, I
20μs / div 20μs / div
1kHz, 3 series LED, I
LED
LED
LED. The magnitude is zero when the diode is off. The average of LED current
CEH, and the low level, lower
=20mA
=20mA 1kHz, 4 series LED, I
LED so that the minimum necessary current is gained
LED1 should be such that a desired increase of current passed
Ω
Ω
10kHz, 4 series LED, I
200μs / div 200μs / div
LED and in series with RLED1 and
LED
=20mA
LED
=20mA
Figure Circuit using Step-wise Regulation of LED Current
8/15
A
XC9133
Series
■
PPLICATION 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>>R
LED = (VREF - R1 / R2 (VDC - VREF)) / RLED
I
REF = 0.2V (TYP.)
V
Ex.1) When R1 = 10k Ω, R2 = 100k Ω, RLED = 10 Ω,
In the range of 0.2V to 2.2V DC, I
(LED current) varies bet ween 20mA to 0mA.
Ex.2) When R1 = 10k Ω, R2 = 100k Ω, R3 = 10k Ω,
C1 = 0.1μF, RLED = 10Ω, the average LED current will
<Prevent Emission Caused by White LEDs Leakage>
When the input voltage (V
happens, please connect a transistor to between the LED and the F B pin. By driving the CE signal in-ph ase and cutting
the pass to current, the minimum illumination can be prevented.
LED, ILED which flows into LEDs can be calculated by the following equation;
LED
Figure Circuit using DC voltage
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
IN) is high, minimum illumination may occur even if the CE pin is in the disable state. If this
SBD
XBS053V15R
Lx
R
10Ω
LED
XP151A12A2
20mA
V
IN
3.6V
(3.2V~6.0V)
C
IN
4.7μF
L:22μH
VLF3010A
V
IN
CE FB
V
SS
V
DC
C
L
0.22μF
(base)
I
XC9133
FB
R2 R1
LED
R
LED
Figure Circuit Prevent Emission Caused by White LEDs Leakage
9/15
A
XC9133 Series
■
PPLICATION 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
10/15
A
pply
XC9133
Series
■
PPLICATION INFORMATION (Continued)
<Separate Supply Source of the Step-up Circuit (VIN) from VIN Pin>
Su
source of the step-up circuit can be used separatelyfrom VINpin.
Circuit example of separating supply source of
the step-up circuit from V
Note: Please input 2.5V~6V to the V
IN pin ( 3 LEDs)
IN 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 ma ximum.
Accordingly, the output voltage continues to increase, possibly causing the Lx pin voltage to exceed the absolute ma ximum
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 I
LIM.
In some cases, overshoot can occur.
Circuit example of separating supply source of
the step-up circuit from V
IN pin ( 2 LEDs)
11/15
A
XC9133 Series
■
12/15
PPLICATION INFORMATION (Continued)
<Instruction on Pattern Layout>
1. In order to stabilize V
possible to the V
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
IN's voltage level, we recommend that an input by-pass capacitor (CIN) be connected as close as
IN & VSS pins.
■TEST CIRCUITS
●Circuit ① (XC9133B02A Series)
L:22uH
CDRH3D16
SBD
XBS053V15R
V
IN
V
IN
C
IN
4.7μF
(ceramic)
CE FB
V
CE
Lx
C
L
0.22μF
V
SS
R
LED
V
(ceramic)
●Circuit ②
●Circuit ③
●Circuit ④
1. The measurement method of L
Using the circuit ④, Lx ON resistance can be measured by adjusting V
driver transistor is ON.
The oscilloscope is used for measuring the Lx voltage when the driver transistor is ON.
RSWON = 0.4 / ((V
PULL
2. The measurement method of current limit I
Using the circuit ④, current limit ILIM can be calculated by the equation including V
decreased while V
voltage is adjusted and Lx voltage VLX when the driver transistor is ON.
PULL
ON Resistance R
X
- 0.4) /10)
LIM
SWON
voltage to set Lx voltage VLX 0.4V when the
PULL
The oscilloscope is used for measuring the Lx voltage when the driver transistor is ON.
I
R
LIM = (V
PULL
＝
PULL
10Ω
- VLX) / R
PULL
XC9133
Series
voltage when FB voltage is
PULL
13/15
XC9133 Series
■PACKAGING INFORMATION
●SOT-25
(unit : mm)
+0.1
0.4
-0.05
■ MARKING RULE
SOT25
●SOT-25
14/15
2.9±0.2
5 4
1
2
(0.95)
3
1.9±0.2
54
① ② ③ ④ ⑤
123
0～0.1
+0.1
0.15
-0.05
① represents product series
MARK PRODUCT SERIES
N XC9133****M*
② represents Lx overvoltage limit
MARK Lx OVERVOLTAGE LIMIT PRODUCT SERIES
B Available XC9133****M*
③ represents oscillation frequency
MARK OSCILLATION FREQUENCY PRODUCT SERIES
A 1MHz XC9133****M*
④⑤
represents production lot number
01 to 09, 0A to 0Z, 11 to 9Z, A1 to A9, AA to Z9, ZA to ZZ repeated.
(G, I, J, O, Q, W excepted)
* No character inversion used.
XC9133
Series
1. The products and product specifications contained he rein 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 dat asheet 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
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