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YB1313
1x/1.5x/2x Charge Pump for White LED Application Description
The YB1313 charge pump is designed to drive up to 5 white LEDs with regulated constant current in back lit display application. The device can provide up to 25 mA per LED for a total of more than 125 mA. The input voltage ranges from 2.7V to 5.5V and is ideal for applications powered by a single LI-Ion or 3 to 4 NiCd, NiMH or Alkaline batteries. The 1MHz fix-frequency switching allows for tiny external components, and the regulation scheme is optimized to ensure low EMI and low input ripple. Internal soft-start circuitry effectively reduces the in-rush current. YB1313 also provides short circuit protection, over-temperature protection and over-voltage protection. In shutdown mode, the shutdown current is less than 1A. YB1313 is available in a TQFN-16 3x3 package.
Features
Input Range : 2.7V to 5.5V Drives up to 5 LEDs at 25mA Each 1MHz Internal Oscillator Thermal Protection Shutdown Output Short-circuit Current Limit and Over-voltage Protection Under-Voltage Lockout With Hysteresis Automatic Soft-Start Reduces In-Rush Current Three Charge Pump Mode1x/1.5x/2x 3mm x 3mm TQFN package
Applications
White LED Backlighting Handheld PCs and PDAs Mobile Phone
Typical Application Circuit
VIN VIN = 2.7V To 5.5V 0. 47 F C1C2+ 0. 47 F C2EN1 1 F EN2 C1+
VOUT D1 D2
2.2uF
YB 1313
D3 D4 D5 ISET
GND PGND
Figure 1. Typical application circuit YB1313 MRev.1.1 www.yobon.com.tw 1
YB1313
1x/1.5x/2x Charge Pump for White LED Application Pin Configuration
TQFN-16 3x3 Package
C1+
10
VIN GND EN1 EN2
13 14 15 16 1
12
11
C2+
9 8 7 6 5
C2-
C1-
VOUT PGND D1 D2
2
3
4
ISET
D5
D4
Figure 2. Pin configuration
Pin Description
Table 1
Pin
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Name
ISET D5 D4 D3 D2 D1 PGND VOUT C2+ C1+ C1C2VIN GND EN1 EN2
Description
Connect a RSET resistor between this pin and GND. RSET=10K, set ILED to 20 mA (Recommanded) Current sink output #5. If not used, connected to VIN or floating Current sink output #4. If not used, connected to VIN or floating Current sink output #3. If not used, connected to VIN or floating Current sink output #2. If not used, connected to VIN or floating Current sink output #1. If not used, connected to VIN or floating Power GND Charge pump output Flying capacitor 2 positive terminal. Connect a 0.47F capacitor between C2+ and C2-. Flying capacitor 1 positive terminal. Connect a 0.47F capacitor between C1+ and C1Flying capacitor 1 negative terminal Flying capacitor 2 negative terminal Input Voltage Analog GND Enable input1 Enable input2. EN1 and EN2 can be used for digital dimming with 4 steps from 0mA to the maximum current set with ISET.
Ordering Information
Table 2
Order Number YB1313QF33
YB1313 MRev.1.1
Package Type TQFN 3X3
Supplied as 2500 units Tape & Reel
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D3
Package Marking 1313
2
YB1313
1x/1.5x/2x Charge Pump for White LED Application Absolute Maximum Ratings
Supply Voltage.................................................. 6.5V Output Voltage.................................................. 5.5V Output Short-Circuit Duration................Continuous Junction Temperature Range ........................ +125 Storage Temperature Range............-65 to +150 Lead Temperature ......................................... +250
Recommended Operating Conditions
Input Supply Voltage ........................ 2.7V to 5.5V Operating Temperature................. -40 to +85
Electrical Characteristics
Table 3
SYMBOL
At TA=25, VIN=3.5V,
CIN=1F, C1=C2=0.47F, COUT=2.2F, EN1=EN2=VIN, unless otherwise noted.
TEST CONDITIONS MIN TYP MAX UNIT
PARAMETER
SUPPLY VOLTAGE AND CURRENT VIN IQ ISD Input voltage range Operating quiescent current Shutdown current 1x 1.5x VIN = 3.5V, EN1 = EN2 = 0V 2.7 800 3 1 5.5 V A mA A
CHARGE PUMP STAGE VOUT FOSC CP Over-voltage limit Switching frequency Charge pump efficiency Shutdown temperature Recovery temperature CURRENT SINKS k ILED/ILED(min) ILED/VIN ILED to ISET current ratio Current matching between any two outputs2 Line regulation EN1=EN2=1, RISET=10K VLED = 3.5V, TA = 25 2.7V < VIN < 4.3V EN1 = 1, EN2 = 0 VISET Reference voltage for current set EN1 = 0, EN2 = 1 EN1 = 1, EN2 = 1 ENABLE 1, ENABLE 2 V (UVLO) Under-Voltage Lockout UVLO hysteresis VIH VIL FPWM EN1, EN2 Threshold high EN1, EN2 Threshold low Frequency range at PWM VIN = 5.5V VIN = 2.7V EN1, EN2 shorted for PWM control 0 1.6 0.4 5 Supply voltage falling 2.3 100 V mV V V kHz 600 2.0 290 320 0.4 3.0 200 400 620 640 350 2.0 4.0 % %/V mV mV mV VIN = 3.5V, 1.5x mode Temperature rising Temperature falling LED unconnected, VIN=4.2V 0.6 5.5 0.8 93 160 140 1 V MHz %
YB1313 MRev.1.1
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YB1313
1x/1.5x/2x Charge Pump for White LED Application Typical Characteristics
VIN=3.6V, CIN=C1=C2=1F, COUT=2.2F, unless otherwise noted.
Efficiency vs. Supply Voltage (Full Load)
1.5X Mode Inrush Current 2/3 Load
100 90
Efficiency (%)
80 70 60 50 40 30 2.7 2.9 3.1 3.3 3.5 3.7 3.9 4.1 4.3
EN0/EN1 DC Coupled 5V/Div VOUT DC Coupled 5V/Div IIN DC Coupled 500mA/Div
Supply Voltage (V)
Time=500s/div
1.5X Mode, 2/3 Load
1.5X Mode Inrush Current Full Load
VOUT DC Coupled 50mV/Div C2DC Coupled 2V/Div VDX DC Coupled 1V/Div
EN0/EN1 DC Coupled 5V/Div VOUT DC Coupled 5V/Div IIN DC Coupled 500mA/Div
Time=1s/div
Time=500s/div
1.5X Mode, Full Load
VOUT DC Coupled 50mV/Div C2DC Coupled 2V/Div VDX DC Coupled 1V/Div
Time=1s/div
YB1313 MRev.1.1
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YB1313
1x/1.5x/2x Charge Pump for White LED Application Functional Block
PGND 7 VOUT 8 2 3 1x/1.5x/2x Charge Pump Current Sinks 4 5 6 D5 D4 D3 D2 D1
C1+ C1C2+ C2VIN
10 11 9 12 13 + Reference -
Selmin
EN1 EN2
15 16
Control
1
ISET
14 GND
Figure 3. Block Diagram
Functional Description
The YB1313 uses a multi-mode fractional charge pump to generate a supply voltage and a precise sink circuitry to ensure a constant driving current for each LED. The charge pump operates in either 1x mode, 1.5x mode or 2x mode, depending on the input voltage and output current loading. The overall power consumption is best optimized by automatically switching among the 3 different operation mode.
YB1313 MRev.1.1
The charge pump is possible to generate a total output current of more than 125 mA, more than 25 mA for each LED. But it is recommended to operate the device under total 125 mA. Connecting a RSET resistor of 10K ohm from pin ISET to ground generates around 20 mA LED output current and a RSET of 7.5K generates around 26 mA.
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YB1313
1x/1.5x/2x Charge Pump for White LED Application Applications Information
Soft-Start Circuitry The YB1313 includes soft-start circuitry to limit inrush current at turn-on. Once the input voltage is applied, the output capacitor is charged directly from the input with a ramped current source (with no charge-pump action) until the output voltage approaches the input voltage. Once this occurs, the charge pump determines if 1x, 1.5x, 2x mode is required. In the case of 1x mode, the soft-start is terminated and normal operation begins. In the case of 1.5x or 2x mode, soft-start operated until the lowest of LED1-LED4 reaches regulation. ENABLE (EN1, EN2) The enable pins EN1 and EN2 are used to enable the device or set it into shutdown. The YB1313 is enabled if one of the enable pins is pulled higher than the enable trip point of 1.2V. The device starts up by going through the soft start routine as described in the section Soft Start. Pulling both pins to GND, after a delay, programs the device to shutdown. In shutdown, the charge pump, current sources, voltage reference, oscillator, and all other functions are turned off and the supply current is reduced to 0.1A. EN1 and EN2 can also be used for dimming. The logic levels at EN1 and EN2 set the minimum voltage at the current mirrors and the voltage at the ISET pin to GND. This sets the current at the LEDs to be either the full current or a fraction of the full current. See Table 4 for further details. The maximum current through the LEDs is set by a resistor connected between
YB1313 MRev.1.1
ISET and GND. EN1 and EN2 can also be used for PWM dimming. The PWM signal can either be applied to EN1 or EN2, or both inputs can be tied together and the PWM signal can be applied to both pins. Depending on the configuration, the current during PWM dimming is switched between 0 mA and its maximum (EN1 and EN2 connected to the PWM signal) or between 0 mA and 1/3 of the full LED current if EN2= 0 and EN1 is toggled. When EN1 = 0 and EN2 is toggled, the output current can be changed between 0 mA and 2/3 of the full range.
Table 4. Enable Levels
Enable Level EN2 0 0 1 1 EN1 0 1 0 1
MODE Shutdown VISET=200mV VISET=400mV VISET=620mV
LED Current 0 1/3 2/3 Full
LED Current Setting The current of white LED connected to YB1313 can be set by RSET. Every current flows through the white LED is 320 times greater than the current of RSET. The white LED can be estimated by following equation:
V I LED = 320 x ISET R SET
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YB1313
1x/1.5x/2x Charge Pump for White LED Application
Thermal Protection The regulator has thermal shutdown circuitry that protects it from damage caused by high temperature conditions. The thermal protection circuitry shut down the device when the junction temperature reached approximately 160, allowing the device to cool. When the junction temperature cools to approximately 140, the device is automatically reenabled. Continuously running the regulator into thermal shutdown can degrade reliability. Undervoltage Lockout The undervoltage lockout circuit shuts down the device when the voltage at VIN drops below a typical threshold of 2.2V. The prevents damage to the devices. Termination of Unused Current Source Outputs If any outputs (D1 to D5) are not used, the LEDs pin should be connected to VDD or floating. Figure 4 shows the connection for 4LEDs application, D5 pin is connection to VDD directly. Power Efficiency The battery current and efficiency of the YB1313 are mostly dependent on the chare pump mode of operation. To get the best performance form the YB1313 it is better to use LEDs with consistently lower VF voltage. Lower VF will keep the charge pump in 1x mode longer and will uses less battery current, extending the run time of the battery. The power conversion efficiency of the YB1313 can be calculated by adding up the products of each LED current and voltage and dividing it by the product of the input voltage and current. With a fully charged battery where the input voltage is typically above the LED forward voltage, the charge pump operates in the 1x mode and efficiency is high. As the battery discharges, there is a point where the current sources no longer have enough voltage overhead to maintain a constant current regulation. At that point, the charge pump switches into the 1.5x mode. The conversion efficiency is lowest at the crossover. When in 1x mode the voltage conversion efficiency is defined as output power divided by input power:
=
POUT VOUT x I OUT = x100% PIN VIN x I IN POUT VOUT x I OUT = x 100% PIN VIN x ( I OUT + I Q )
I IN = I OUT + I Q
=
Figure 4. Application for 4 LEDs. YB1313 MRev.1.1
When in 1.5x or 2x mode the voltage conversion efficiency is as output power divided by input power:
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YB1313
1x/1.5x/2x Charge Pump for White LED Application
POUT VOUT x I OUT = x100% PIN VIN x I IN POUT VOUT x I OUT = x100% PIN VIN x ( I OUT x Mode + I Q )
=
I IN = I OUT + I Q
=
Mode = 1.5 or 2
And then LEDs efficiency is defined as LED forward voltage produces output current divided by input power:
=
POUT VF x I OUT = x 100% PIN VIN x ( I OUT x Mode + I Q )
Capacitor Selection
Ceramic capacitors such as X5R or X7R are recommended to be used with the YB1313. For the two flying capacitors C1 and C2, it is important to use low ESR capacitors to avoid unnecessary efficiency losses. Low ESR capacitors on VOUT reduce the ripple voltage on the supply of the current sources. Table 5 lists capacitor types that have been tested with the YB1313.
Table 5. Recommended Capacitors and WLED
Part C1608X5R1A105KT000E C1608X7R1A105KT0S0N C2012X7R1C225KT000N ECJ1VB1A105K ECJ2FB1A105K ECJ2FB1A225K LTW-193TS5
Value 1F 1F 2.2F 1F 1F 2.2F
Voltage 10V 10V 16V 10V 10V 16V
Manufacturer
Size 0603
Website
TDK
0805 0805 0603
www.component.tdk.com
Panasonic
0805 0805
www.panasonic.com
Lite-On
www.liteon.com.tw
YB1313 MRev.1.1
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8
YB1313
1x/1.5x/2x Charge Pump for White LED Application Package Information
Figure 5.
YB1313 MRev.1.1
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