PT4115B89E-B datasheet, PDF - EEWORLD Datasheet

PT4115

30V, 1.2A Step-down High Brightness

LED Driver with 5000:1 Dimming

GENERAL DESCRIPTION

The PT4115 is a continuous conduction mode inductive

step-down converter, designed for driving single or

multiple series connected LED efficiently from a

voltage source higher than the total LED chain voltage.

The device operates from an input supply between 6V

and 30V and provides an externally adjustable output

current of up to 1.2A. Depending upon the supply

voltage and external components, the PT4115can

provide more than 30 watts of output power.

The PT4115 includes the power switch and a high-side

output current sensing circuit, which uses an external

resistor to set the nominal average output current, and a

dedicated DIM input accepts either a DC voltage or a

wide range of pulsed dimming. Applying a voltage of

0.3V or lower to the DIM pin turns the output off and

switches the device into a low current standby state.

The PT4115 is available in SOT89-5 and ESOP8

packages.

FEATURES



Simple low parts count

Wide input voltage range: 6V to 30V

Up to 1.2A output current

Single pin on/off and brightness control using DC

voltage or PWM

Up to 1MHz switching frequency

Typical 5% output current accuracy

Inherent open-circuit LED protection

High efficiency (up to 97%)

High-Side Current Sense

Hysteretic Control: No Compensation

Adjustable Constant LED Current

ESOP8 package for large output power application

RoHS compliant

APPLICATIONS



Low voltage halogen replacement LEDs

Automotive lighting

Low voltage industrial lighting

LED back-up lighting

Illuminated signs

SELV lighting

LCD TV backlighting

ORDERING INFORMATION

PACKAGE

SOT89-5

ESOP8

Note:

xxxxxX

Assembly Factory Code

Lot Number

TEMPERATURE

RANGE

-40

o

C to 85

o

C

-40

o

C to 85

o

C

ORDERING PART

NUMBER

PT4115B89E:A type

PT4115B89E-B:B type

PT4115BSOH:A type

PT4115BSOH-B:B type

TRANSPORT

MEDIA

Tape and Reel

1000 units

Tape and Reel

2500 units

MARKING

PT4115

xxxxxX

PT4115

xxxxxX

TYPICAL APPLICATION CIRCUIT

V

IN

DC6-30V

R

S

0.13Ω

LED

3W

L

68uH

D

C

IN

AC12-18V

100uF

VIN

CSN

SW

DIM

PT4115

GND

China Resources Powtech (Shanghai) Limited

PT4115_DS Rev EN_2.9

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Page 1

PT4115

30V, 1.2A Step-down High Brightness

LED Driver with 5000:1 Dimming

PIN ASSIGNMENT

CSN

VIN

SW

NC

1

2

3

4

8

7

6

5

DIM

GNDA

GNDP

NC

ESOP8

PT4115

PIN DESCRIPTIONS

PIN No.

1

2

3

4

5

-

ESOP8 4,5

NAMES

SW

GND

DIM

CSN

VIN

Exposed

NC

PAD

DESCRIPTION

Switch Output. SW is the drain of the internal N-Ch MOSFET switch.

Signal and power ground. Connect directly to ground plane.

Logic level dimming input. Drive DIM low to turn off the current regulator.

Drive DIM high to enable the current regulator.

Current sense input

Input Supply Pin. Must be locally bypassed.

Internally connected to GND. Mount on board for lower thermal resistance.

No connection

ABSOLUTE MAXIMUM RATINGS

(note1)

SYMBOL

V

IN

SW

CSN

DIM

I

SW

P

DMAX

P

TR

P

TR

T

J

T

STG

ITEMS

Supply Voltage

Drain of the internal power switch

Current sense input (Respect to VIN)

Logic level dimming input

Switch output current

Power Dissipation (Note 2)

Thermal Resistance, SOT89-5

Thermal Resistance, ESOP8

θ

JA

θ

JA

VALUE

-0.3~45

+0.3~(-6.0)

-0.3~6

1.5

45

40

-40 to 150

-55 to 150

2

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o

UNIT

V

A

W

C /W

o

Operation Junction Temperature Range

Storage Temperature

ESD Susceptibility (Note 3)

C

kV

Page 2

China Resources Powtech (Shanghai) Limited

PT4115_DS Rev EN_2.9

PT4115

30V, 1.2A Step-down High Brightness

LED Driver with 5000:1 Dimming

RECOMMENDED OPERATING RANGE

SYMBOL

V

IN

T

OPT

ITEMS

V

DD

Supply Voltage

Operating Temperature

VALUE

6 ~ 30

-40 to +85

UNIT

V

o

C

Note 1:

Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Recommended

Operating Range indicates conditions for which the device is functional, but do not guarantee specific performance

limits. Electrical Characteristics state DC and AC electrical specifications under particular test conditions which

guarantee specific performance limits. This assumes that the device is within the Operating Range. Specifications are

not guaranteed for parameters where no limit is given, however, the typical value is a good indication of device

performance.

Note 2:

The maximum power dissipation must be derated at elevated temperatures and is dictated by T

JMAX

, θ

JA

,

and the ambient temperature T

A

. The maximum allowable power dissipation is P

DMAX

= (T

JMAX

- T

A

)/ θ

JA

or the

number given in Absolute Maximum Ratings, whichever is lower.

Note 3:

Human body model, 100pF discharged through a 1.5kΩ resistor.

ELECTRICAL CHARACTERISTICS

(Note 4, 5)

The following specifications apply for V

IN

=12V, T

A

=25

o

C, unless specified otherwise.

SYMBOL

V

IN

V

UVLO

V

UVLO, HYS

F

SW

Current Sense

V

CSN

V

CSN_hys

I

CSN

Mean current sense

threshold voltage

Sense threshold hysteresis

CSN Pin Input Current

Quiescent

supply current

V

IN

-V

CSN

=50mV

V

IN

-V

CSN

A type

B

type

95

99

98

102

±

15

8

101

105

mV

%

µA

ITEMS

Input Voltage

Under voltage lock out

UVLO hysterisis

Max. Switching Frequency

V

IN

falling

V

IN

rising

CONDITIONS

Min.

6

5.1

500

1

Typ.

Max.

30

UNIT

V

mV

MHz

Operating Current

I

OFF

DIM Input

V

DIM

V

DIM_H

V

DIM_L

V

DIM_DC

f

DIM

D

PWM_LF

Internal supply voltage

DIM input voltage High

DIM input voltage Low

DC brightness control

Max. DIM Frequency

Duty cycle range of low

frequency dimming

Brightness control range

f

OSC

=500kHz

f

DIM

=100Hz

0.02%

5000:1

0.5

DIM floating

2.5

0.3

2.5

50

1

5

V

kHz

with output off

V

DIM

<0.3V

95

µA

China Resources Powtech (Shanghai) Limited

PT4115_DS Rev EN_2.9

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Page 3

PT4115

30V, 1.2A Step-down High Brightness

LED Driver with 5000:1 Dimming

ELECTRICAL CHARACTERISTICS (Continued)

(Note 4, 5)

SYMBOL

DIM Input

D

PWM_HF

Duty

cycle

range

of

high

frequency dimming

Brightness control range

R

DIM

I

DIM_L

Output Switch

R

SW

I

SWmean

I

LEAK

T

SD

T

SD

-hys

SW On Resistance

Continuous SW Current

SW Leakage Current

Thermal Shutdown Threshold

Thermal Shutdown hysteresis

0.5

160

20

VIN=12V

VIN=24V

0.6

0.4

1.2

5

Ω

A

µA

℃

DIM pull up resistor to Internal

supply voltage

DIM input leakage low

V

DIM

= 0

f

DIM

=20KHz

4%

25:1

200

25

KΩ

uA

1

ITEMS

CONDITIONS

Min.

Typ.

Max.

UNIT

Thermal Shutdown

Note 4:

Typical parameters are measured at 25˚C and represent the parametric norm.

Note 5:

Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis.

SIMPLIFIED BLOCK DIAGRAM

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PT4115_DS Rev EN_2.9

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Page 4

PT4115

30V, 1.2A Step-down High Brightness

LED Driver with 5000:1 Dimming

OPERATION DESCRIPTION

The device, in conjunction with the coil (L1) and

current sense resistor (RS), forms a self oscillating

continuous-mode buck converter.

When input voltage VIN is first applied, the initial

current in L1 and RS is zero and there is no output from

the current sense circuit. Under this condition, the

output of CS comparator is high. This turns on an

internal switch and switches the SW pin low, causing

current to flow from VIN to ground, via RS, L1 and the

LED(s). The current rises at a rate determined by VIN

and L1 to produce a voltage ramp (V

CSN

) across RS.

When (V

IN

-V

CSN

) > 115mV, the output of CS

comparator switches low and the switch turns off. The

current flowing on the RS decreases at another rate.

When (V

IN

-V

CSN

) < 85mV, the switch turns on again

and the mean current on the LED is determined by

(V

DIM

) to adjust the output current to a value below the

nominal average value defined by RS. The DC voltage

is valid from 0.5V to 2.5V. When the dc voltage is

higher than 2.5V, the output current keeps constant.

The LED current also can be adjusted by a resistor

connected to the DIM pin. An internal pull-up resistor

(typical 200KΩ) is connected to a 5V internal regulator.

The voltage of DIM pin is divided by the internal and

external resistor.

The DIM pin is pulled up to the internal regulator (5V)

by a 200KΩ resistor. It can be floated at normal

working. When a voltage applied to DIM falls below

the threshold (0.3V nom.), the output switch is turned

off. The internal regulator and voltage reference remain

powered during shutdown to provide the reference for

the shutdown circuit. Quiescent supply current during

shutdown is nominally 95uA and switch leakage is

below 5uA.

Additionally, to ensure the reliability, the PT4115 is

built with a thermal shutdown (TSD) protection and a

thermal pad. The TSD protests the IC from over

temperature (160℃). Also the thermal pad enhances

power dissipation. As a result, the PT4115 can handle a

large amount of current safely.

(

85+2115

mV

) /

R

S

= 100

mV

/

R

S

.

The high-side current-sensing scheme and on-board

current-setting circuitry minimize the number of

external components while delivering LED current with

± accuracy, using a 1% sense resistor.

5%

The PT4115 allow dimming with a PWM signal at the

DIM input. A logic level below 0.3V at DIM forces

PT4115 to turn off the LED and the logic level at DIM

must be at least 2.5V to turn on the full LED current.

The frequency of PWM dimming ranges from 100Hz to

more than 20 kHz.

The DIM pin can be driven by an external DC voltage

China Resources Powtech (Shanghai) Limited

PT4115_DS Rev EN_2.9

WWW.CRPOWTECH.COM

Page 5

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