YB1518芯片引脚定义引脚图及功能IC贸易商引脚图技术参数-中国IC网-芯三七

YB1518

Step-up DC-DC Converter White LED Driver

Description

Features

The YB1518 is a step-up DC-DC converter;

operates as current source to drive up to 6

white LEDs(VIN at 3.0V) or 8 LEDs(VIN at

3.4V) or 9 LEDs(VIN at 3.4V) in series.

Series connecting of the LEDs provides

identical LED currents resulting in uniform

brightness and eliminating the need for

ballast resistors. The light intensity of these

LEDs is proportional to the current passing

through them. The YB1518 switches at a

fixed frequency of ~1MHz, allowing the use

of tiny, low profile inductors and capacitors

to minimize footprint and cost in space

consideration applications for cellular

phone backlighting or other hand held

equipment.

Built-in internal switch

2.7V to 16V input range

<1uA shutdown current

High efficiency

Internal Soft Start

Drives up to 9 white LEDs(VIN at 3.4V)

Over voltage protection 36V

Small 5-Lead SOT-23 package

100mV Low Reference Voltage

Applications

LCD Display Module

The YB1518 can drive up to 9 white LEDs

from a single Li-Ion battery. The wide input

voltage range from 2.7V to 16V is ideal for

White LED Backlighting

PDAs, GPS terminals

Digital Cameras

portable

applications

and

with

automotive

higher

(5V/12V)

conversion

Cellular Phone

efficiency. To control LED brightness, the

LED current can be pulsed by applying a

PWM (pulse width modulated) signal with a

frequency range of 100Hz to 1KHz to the

CTRL pin.

Electronic Books

Portable Applications

YB1518 has integrated Latched Over

Voltage Protection that prevents damage to

the device in case of a high impedance

output due to faulty LED or open circuit

caused by abnormal conditions.

Typical Application Circuit

Figure 1: Typical Application Circuit

YB1518 MRev.1.2

www.yobon.com.tw

1

YB1518

Step-up DC-DC Converter White LED Driver

Pin Configuration

Figure 2: YB1518 Pin Configuration

Pin Description

Table 1

NAME

Description

Switching Pin. This is the collector of the internal NPN power

SW

switch. Connect to inductor and diode. Minimize the metal

trace area connected to this pin to reduce EMI.

1

GND

FB

Ground Pin. Connect directly to local ground plane.

2

3

Feedback Pin. Reference voltage is 100mV. Connect LEDs

and a resistor at this pin. LED current is determined by the

resistance and CTRL voltage.

Shutdown Pin and Dimming Control pin.

VCTRL > 1.8V generates full-scale LED current

VCTRL < 0.4V chip is off

CTRL

VIN

4

5

Switching from 0.4V to 2.0V, PWM duty cycle controls the LED

current

Input Supply Pin. Bypass this pin with a capacitor as close to

the device as possible

Ordering Information

Table 2

Order Number

Supplied as

Package Marking

YB1518ST25

3000 units Tape & Reel

Y58M

YB1518 MRev.1.2

www.yobon.com.tw

2

YB1518

Step-up DC-DC Converter White LED Driver

Absolute Maximum Ratings

Recommended Operating Conditions

Operating Temperature ............................-40°C~85°C

VIN.........................................................................20V

SW Voltage............................................................36V Supply Voltage............................................ 2.7 V~16V

FB Voltage ...............................................................5V SW Voltage............................................................32V

CTRL Voltage...........................................................5V

Maximum Junction Temp,TJ .............................150°C

Lead Temperature (Slokering 10 sec) ................300°C

Thermal Resistance............................................195°C

Electricity Characteristics

(TA=25°C, Vin=3.3V, Cin=1uF Cout=10uF unless otherwise noted) Table 3

Symbol

Function Parameter

Input Voltage Range

Not Switching

Test Conditions

Min

2.7

Typ

Max

16

Units

V

Vin

VFB = 0.3V

CTRL = 0V

1.2

1.5

0.3

1.7

1

mA

uA

IQ (Quiescent

Current)

Shutdown

Iout=20mA,Vout=12.5V

Circuit of Figure 1

VFB

ICL

Feedback Voltage

90

100

110

mV

100% duty cycle

40% duty cycle

400

450

350

mA

Switch Current Limit

IB

FB Pin Bias Current

Switching Frequency

VFB=100mV

1

uA

FRSW

900

20

930

960

KHz

DTMX

DTMN

VSAT

Maximum Duty Cycle

Minimum Duty Cycle

Switch Vcesat

85

25

%

At Isw = 200mA

Ctrl = 0.3V

180

mV

Switch Leakage

Current

ILKG

1

μA

VCTRL for Full LED

Current

Full On

Full Off

1.7

V

VCTL

ICTL

0.3

CTRL Pin Bias Current

Ctrl = 2V

40

μA

Over Voltage

Protection

OVP

34

V

θJA

Thermal Resistance

220

°C/W

Note:

Absolute maximum ratings are limits beyond which damage to the device may occur.

The maximum allowable power dissipation is a function of maximum function temperature , TJ(max), the

junction to ambient thermal resistance, θJA , and the ambient temperature. The maximum allowable, power

dissipation at any ambient temperature is calculated using: PD(MAX)= [TJ(max)-TA]/θJA . Exceeding the

maximum allowable power dissipation will cause excessive die temperature. All limits at temperature

extremes are guaranteed via correlation using standard statistical methods

YB1518 MRev.1.2

www.yobon.com.tw

3

YB1518

Step-up DC-DC Converter White LED Driver

Typical Performance Characteristics

Condition : VIN 2.8V ; 4.4V

VOUT ; 2pcs white LEDs

/

VCRTL : 3V

Condition : VIN 2.8V ; 4.4V

VOUT ; 3pcs white LEDs

/ VCTRL: 3V

Efficiency vs Vin (2WLEDs)

Efficiency vs Vin (3WLEDs)

83.0

82.5

82.0

81.5

81.0

82

81

80

79

78

2.7

3.0

3.3

3.6

3.9

4.2

4.5

2.7

3.0

3.3

3.6

3.9

4.2

4.5

Vin(V)

YB1518 MRev.1.2

www.yobon.com.tw

4

YB1518

Step-up DC-DC Converter White LED Driver

Condition : Vin 2.8V ; 4.4V

VOUT ; 4pcs white LEDs

/

Vctrl : 3V

Condition : Vin 2.8V ; 4.4V

VOUT ; 5pcs white LEDs

/ Vctrl : 3V

Efficiency vs Vin (5WLEDs)

Efficiency vs Vin (4WLEDs)

83

82

81

80

79

83

81

79

77

75

2.7

3.0

3.3

3.6

3.9

4.2

4.5

2.7

3.0

3.3

3.6

3.9

4.2

4.5

Vin(V)

YB1518 MRev.1.2

www.yobon.com.tw

5

YB1518

Step-up DC-DC Converter White LED Driver

Condition : Vin 2.8V ; 4.4V

VOUT ; 6pcs white LEDs

/

Vctrl : 3V

Condition : Vin 3.0V ;4.4V

VOUT ; 7pcs white LEDs

/ Vctrl : 3V

Efficiency vs Vin (6WLEDs)

Efficiency vs Vin (7WLEDs)

80

78

76

74

72

70

82

80

78

76

74

72

2.7

3.0

3.3

3.6

3.9

4.2

4.5

2.7

3.0

3.3

3.6

3.9

4.2

4.5

Vin(V)

YB1518 MRev.1.2

www.yobon.com.tw

6

YB1518

Step-up DC-DC Converter White LED Driver

Condition : Vin 3.0V ; 4.4V

VOUT ; 8pcs white LEDs

/

Vctrl : 3V

Condition : Vin 3.4V ; 6.0V

VOUT ; 9pcs white LEDs

/ Vctrl : 3V

Efficiency vs Vin (8WLEDs)

Efficiency vs Vin (9WLEDs)

80

78

76

74

72

70

81

78

75

72

69

3.0

3.5

4.0

4.5

5.0

5.5

6.0

6.5

2.7

3.0

3.3

3.6

3.9

4.2

4.5

Vin(V)

YB1518 MRev.1.2

www.yobon.com.tw

7

YB1518

Step-up DC-DC Converter White LED Driver

Typical Performance Characteristics

Supply Current (Vctrl = 0V)

Supply Current (Vctrl = Vin)

1

0.8

0.6

0.4

0.2

0

6

5

4

3

2

1

0

uA

mA

2

3

4

5

6

7

8

9

2

3

4

5

6

7

8

9

V

Vcesat

Switching Frequency

250

932.2

932

200

150

100

50

931.8

931.6

931.4

931.2

931

Khz

0

930.8

50

100

150

200

250

300

350

400

2

3

4

5

6

7

8

9

Switching Current ( mA)

Vin(V)

Switch Leakage Current

CTRL Pin Bias Current

0.5

0.4

60

50

40

0.3

uA

uA 30

20

0.2

0.1

0

10

0

2

3

4

5

6

7

8

9

2

3

4

5

6

7

8

9

Vin(V)

Vin (V)

YB1518 MRev.1.2

www.yobon.com.tw

8

YB1518

Step-up DC-DC Converter White LED Driver

Functional Block

Figure 3: YB1518 Block Diagram

Operation

The YB1518 uses a constant frequency,

current mode control scheme to regulate

the output LED current. Its operation can

be understood by referring to the block

diagram in Figure 3. At the start of each

oscillator cycle, a voltage proportional to

the switch current is added to a ramp

output and the resulting sum is fed into the

positive terminal of the PWM comparator

(comparator-1). When this voltage exceeds

the level of the comparator negative input,

the peak current has been reached, and

the SR latch (in Control Logic) is reset and

turns off the power switch. The voltage at

the negative input of the comparator comes

from the output of the error amplifier. The

error amplifier sets the correct peak current

level to keep the output in regulation. If the

error amplifier’s output increases, more

current is delivered to the output; if it

decreases, less current is delivered.

Application Information

Soft Start and Current Limit

The internal soft start circuit minimizes the

inrush current during turning on YB1518.

The maximum switch current is limited to

about 450 mA by the chip.

LED Current and Dimming Control

The LED’s current is set by a resistor

connected at FB pin to GND using:

100mV

I_LED

=

R_LED

The maximum LED current set initially can

be reduced by pulse width modulating the

CTRL. A better approach is to adjust the

feedback voltage for dimming control.

Either a DC level signal or a filtered PWM

signal can be used to control the LED

current as illustrated in Figure 4 and Figure

YB1518 MRev.1.2

www.yobon.com.tw

9

YB1518

Step-up DC-DC Converter White LED Driver

5 respectively. Using the above different

scheme, the LED current can be controlled

from 0% to 100% to its maximum value.

Duty

0%

Iout ( mA)

20

17.4

15

20%

30%

40%

50%

60%

70%

80%

100%

12.4

10

8

6.4

4.07

0

PWM : 2V ; 1KHz ;

Vin=3.6V

VDC(V)

2

VFB Iout(mA)

0

Figure 5. Dimming Control Using

a Filtered PWM Signal

1.8

1.6

1.4

1.2

1

2.2

0.43

1.8

3.6

6

9.2

19.6

31.1

43.4

63

Over Voltage Protection

8.5

12.3

14.5

16.9

19

The YB1518 has an internal over voltage

protection circuit which also acts as an

open-circuit protection. In the cases of

open circuit or the LEDs failure, the LEDs

are disconnected from the circuit, and the

feedback voltage will be zero. The YB1518

will then switch to a high duty cycle

resulting in a high output voltage, which

may cause SW pin voltage to exceed its

maximum 34V rating. The YB1518 will

shutdown automatically until input condition

changes to bring it out of the shutdown

mode.

0.8

0.6

0.4

0.2

0

74

86.4

96.9

102

20

Figure 4. Dimming Control Using

a DC Voltage

Inductor Selection

A 22uH inductor is recommended for most

applications to drive more than 5 LEDs.

YB1518 MRev.1.2

www.yobon.com.tw

10

YB1518

Step-up DC-DC Converter White LED Driver

Although small size and high efficiency are

connections for the Cout capacitor can

increase the series resistance, which

directly effect output voltage ripple.

major concerns, the inductor should have

low core losses at 1MHz and low DCR

(copper wire resistance).

The feedback network, resister R2 should

be kept close to the FB pin to minimize

copper trace connections that can inject

noise into the system. The ground

connection for the feedback resistor

network should connect directly to an

analog ground plane. The analog ground

plane should tie directly to the GND pin. If

no analog ground plane is available, the

ground connection for the feedback

network should tie directly to the GND pin.

Trace connections made to the inductor

and Schottky diode should be minimized to

reduce power dissipation and increase

overall efficiency.

Diode Selection

To maintain high efficiency, the average

current rating of the Schottky diode should

be large than the peak inductor current, IPK.

Schottky diode with a low forward drop and

fast switching speeds are ideal for increase

efficiency in portable application. Choose a

reverse breakdown of the Schottky diode

large than the output voltage.

Capacitor Selection

Choose low ESR capacitors for the output

to minimize output voltage ripple. Multilayer

capacitors are a good choice for this as well.

A 1uF capacitor is sufficient for 2~6 LEDs,

2.2uF is for 7~8 LEDs and 4.7uF is for 9

LEDs

applications.

For

additional

bypassing, a 100nF ceramic capacitor can

be used to shunt high frequency ripple on

the input.

The input bypass capacitor Cin, as shown

in Figure 1, must be placed close to the IC.

This will reduce copper trace resistance

which affects input voltage ripple of the IC.

For additional input voltage filtering, a

100nF bypass capacitor can be placed in

parallel with Cin to shunt any high

frequency noise to ground. The output

capacitor, Cout, should also be placed

close to the IC. Any copper trace

YB1518 MRev.1.2

www.yobon.com.tw

11

YB1518

Step-up DC-DC Converter White LED Driver

Package Description

All the contains in this datasheet are not assuming any responsibility for use of any

circuitry described no circuit patent license are implied and Yobon reserves the right at

any time without notice to change said circuitry and specifications.

Yobon Inc. would like to receive your feedback with your recommends and suggestions

that is always welcome and with our appreciations.

YB1518 MRev.1.2

www.yobon.com.tw

12

型号:	YB1518ST25
生命周期：	Contact Manufacturer
IHS 制造商：	YOBON TECHNOLOGIES INC
Reach Compliance Code：	unknown
风险等级：	5.76
Is Samacsys：	N
接口集成电路类型：	LED DISPLAY DRIVER
Base Number Matches：	1

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