XC9133B02AMR-G [TOREX]

Step-Up DC/DC Converter-LED Backlight Driver; 升压型DC / DC转换器, LED背光驱动器
XC9133B02AMR-G
型号: XC9133B02AMR-G
厂家: Torex Semiconductor    Torex Semiconductor
描述:

Step-Up DC/DC Converter-LED Backlight Driver
升压型DC / DC转换器, LED背光驱动器

驱动器 转换器
文件: 总15页 (文件大小:540K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
XC9133Series  
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.  
FEATURES  
APPLICATIONS  
For White LED drivers  
Mobile phones  
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%  
PDAs  
ON Resistance  
High Efficiency  
: 2.4Ω  
Digital cameras  
: 85%  
3 white LEDs in series  
VIN=3.6V, ILED=20mA  
: PWM control  
Control  
Stand-by Current  
Output Capacitor  
Lx Limit Current  
: ISTB=1.0μA (MAX.)  
: 0.22μF, ceramic  
: 360mATYP.)  
Lx Overvoltage Limit : 19V (TYP.)  
Packages  
: SOT-25  
USP-6C (under development)  
TYPICAL PERFORMANCE  
TYPICAL APPLICATION CIRCUIT  
CHARACTERISTICS  
XC9133B02A Series  
LED NSCW100 x 3  
SBD XBS053V15R,C TMK316J224KF  
L
100  
90  
80  
70  
60  
50  
40  
30  
20  
10  
0
L VLF3010S  
NR3015  
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.  
SOT5 (P VEW)  
USP-6C (BOTTOM VIEW)  
under development)  
PIN ASSIGNMENT  
PIN NUMBER  
PIN NAME  
FUNCTION  
USP-6C  
SOT-25  
(under development)  
1
2
3
4
5
-
2
Lx  
VSS  
FB  
CE  
VIN  
NC  
Switch  
Ground  
3
1
6
4
5
Voltage Feedback  
Chip Enable  
Power Input  
No Connection  
CE PIN FUNCTION  
CE PIN  
OPERATIONAL STATE  
Operation  
H
L
Shut-down  
PRODUCT CLASSIFICATION  
Ordering Information  
(*1)  
XC9133①②③④⑤⑥-⑦  
DESIGNATOR  
DESCRIPTION  
Lx Overvoltage Limit  
FB Voltage  
SYMBOL  
DESCRIPTION  
②③  
B
02  
Available  
0.2V  
Oscillation Frequency  
A
1MHz  
MR  
MR-G  
ER  
SOT-25  
Packages  
Taping Type (*2)  
⑤⑥-⑦  
SOT-25 (Halogen & Antimony free)  
USP-6C (under development)  
(*1) The “-G” suffix indicates that the products are Halogen and Antimony free as well as being fully RoHS compliant.  
(*2) 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-)  
2/15  
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  
SYMBOL  
VIN  
RATINGS  
VSS – 0.3 ~ 7.0  
VSS – 0.3 ~ 22.0  
VSS – 0.3 ~ 7.0  
VSS – 0.3 ~ 7.0  
1000  
UNITS  
V
V
VLx  
VFB  
V
VCE  
V
ILx  
mA  
SOT-25  
USP-6C  
250  
Power Dissipation  
Pd  
mW  
100  
(under development)  
Operating Temperature Range  
Storage Temperature Range  
Topr  
Tstg  
- 40 ~ + 85  
- 55 ~ +125  
3/15  
XC9133 Series  
ELECTRICAL CHARACTERISTICS  
XC9133B02AMR  
Ta = 25℃  
PARAMETER  
SYMBOL  
CONDITIONS  
MIN.  
TYP.  
MAX.  
UNIT. CIRCUIT  
FB Voltage  
VFB  
VOUTSET  
VIN  
IDD1  
IDD2  
ISTB  
fOSC  
MAXDTY  
0.19  
VIN  
2.5  
-
-
-
0.20  
-
-
420  
60  
0
1.0  
92  
0.21  
17.5  
6.0  
720  
140  
1.0  
V
V
V
μA  
μA  
μA  
MHz  
%
Output Voltage Range  
Input Voltage Range  
Supply Current 1  
Supply Current 2  
Stand-by Current  
Oscillation Frequency  
Maximum Duty Cycle  
VIN=VLx, FB=0.4V  
CE=0V, VLx=5.0V  
0.8  
86  
1.2  
98  
When connected to ext.  
components, VIN=3.6V, RLED=20Ω  
When connected to ext. components,  
VIN=3.6V  
Efficiency (*1)  
EFFI  
ILIM  
-
85  
-
%
Current Limit  
260  
360  
460  
mA  
Voltage which Lx pin voltage  
holding ”High” level  
VIN 2.5V  
Lx Overvoltage Limit  
VLxOVL  
18.0  
19.0  
22.0  
V
Lx ON Resistance  
Lx Leakage Current  
RSWON  
ILxL  
VIN=3.6V, VLx=0.4V (*3)  
Same as ISTB  
-
-
2.4  
0.0  
Ω
μA  
1.0  
6.0  
CE applied voltage when Lx starts  
oscillation  
CE applied voltage which Lx pin  
voltage holding “High” level  
Same as IDD2  
CE High Voltage  
CE Low Voltage  
VCEH  
VCEL  
0.65  
VSS  
-
-
V
V
0.2  
CE High Current  
CE Low Current  
FB High Current  
FB Low Current  
ICEH  
ICEL  
IFBH  
IFBL  
-0.1  
-0.1  
-0.1  
-0.1  
-
-
-
-
0.1  
0.1  
0.1  
0.1  
μA  
μA  
μA  
μA  
Same as ISTB  
Same as IDD2  
Same as ISTB  
NOTE: *Test circuit : Unless otherwise stated, VIN=3.0V, VCE=3.0V, RLED=10Ω  
*Test circuit : Unless otherwise stated, VIN=3.0V, VCE=3.0V, VFB=0.0V, VPULL=5.0V, RPULL=100Ω  
*Test circuit : Unless otherwise stated, VIN=3.0V, VCE=3.0V, VFB=0.0V  
*Test circuit : 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  
XC9133  
Series  
TYPICAL APPLICATION CIRCUITS  
XC9133B02A  
EXTERNAL COMPONENTS  
SYMBOL  
VALUE  
PART NUMBER  
VLF3010A-220MR  
XBS053V15R (*2)  
MA2Z720  
MANUFACTURER  
L
22μH  
TDK  
TOREX  
SBD (*1)  
CIN  
-
PANASONIC  
TAIYO YUDEN  
TAIYO YUDEN  
4.7μF  
JMK107BJ475MA-B  
TMK107BJ224KA-B  
(*3)  
CL  
0.22μF  
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  
RLED  
15Ω  
10Ω  
13.3mA  
20mA  
<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, 3 series LED, ILED=20mA  
10kHz, 4 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  
XC9133  
VREF = 0.2V (TYP.)  
FB  
R2  
R1  
Ex.1) When R1 = 10k Ω, R2 = 100k Ω, RLED = 10 Ω,  
In the range of 0.2V to 2.2V DC, ILED  
VDC  
RLED  
(LED current) varies between 20mA to 0mA.  
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  
L:22μH  
XBS053V15R  
VLF3010A  
VIN  
3.6V  
(3.2V~6.0V)  
CL  
0.22μF  
(base)  
VIN  
Lx  
CIN  
XP151A12A2  
20mA  
4.7μF  
CE  
FB  
VSS  
RLED  
10Ω  
Figure Circuit Prevent Emission Caused by White LEDs Leakage  
8/15  
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 VIN3.2V.  
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 (XC9133B02A Series)  
L:22uH  
SBD  
CDRH3D16 XBS053V15R  
VIN  
Lx  
CIN  
4.7μF  
(ceramic)  
VIN  
CL  
0.22μF  
(ceramic)  
CE  
FB  
VSS  
RLED  
V
VCE  
Circuit ②  
Circuit ③  
Circuit ④  
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  
RPULL10  
12/15  
XC9133  
Series  
PACKAGING INFORMATION  
SOT-25  
USP-6C (under development)  
(unit : mm)  
2.9±0.2  
+0.1  
-0.05  
0.4  
5
1
4
3
0~0.1  
2
+0.1  
-0.05  
0.15  
(0.95)  
1.9±0.2  
* Pin no. 1 is wider than other pins.  
13/15  
XC9133 Series  
MARKING RULE  
SOT-25  
Represents product series  
MARK  
PRODUCT SERIES  
XC9133B02AD x  
F
Represents Lx overvoltage limit  
SOT-25  
(TOP VIEW)  
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
PRODUCT SERIES  
XC9133B02AD x  
Represents Lx overvoltage limit  
MARK  
B
Lx OVERVOLTAGE LIMIT  
PRODUCT SERIES  
XC9133B02AD x  
Available  
USP-6C  
(TOP VIEW)  
③④Represents FB voltage  
MARK  
FB VOLTAGE (V)  
0.2  
PRODUCT SERIES  
XC9133B02AD x  
0
2
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.  
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  

相关型号:

XC9140A1824R-G

Switching Regulator,
TOREX

XC9140A331MR-G

Switching Regulator, Voltage-mode, PDSO5,
TOREX

XC9140A392MR-G

Switching Regulator,
TOREX

XC9140A501MR-G

IC REG BST 5V 295MA SYNC SOT-25
TOREX

XC9140C331MR-G

Switching Regulator, Voltage-mode, PDSO5,
TOREX

XC9140C3614R-G

Switching Regulator, Voltage-mode, PDSO6,
TOREX

XC9140C3624R-G

Switching Regulator,
TOREX

XC9140C362MR-G

Switching Regulator,
TOREX

XC9140C371MR-G

Switching Regulator, Voltage-mode, PDSO5,
TOREX

XC9140C3824R-G

Switching Regulator,
TOREX

XC9140C391MR-G

Switching Regulator, Voltage-mode, PDSO5,
TOREX

XC9140C3924R-G

Switching Regulator,
TOREX