TS19453 [TSC]

AC/DC Programmable Current WLED Driver; AC / DC可编程电流WLED驱动器


型号：	TS19453
厂家：	TAIWAN SEMICONDUCTOR COMPANY, LTD
描述：	AC/DC Programmable Current WLED Driver AC / DC可编程电流WLED驱动器驱动器
文件：	总7页 (文件大小：108K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

Preliminary

AC/DC Programmable Current WLED Driver

w/PWM Dimming Control

TS19453

Pin Definition:

1. Rsense

2. Ground

3. PWMD

4. Vdd

SOP-8

8. Drain

7. Drain

6. Drain

5. Ground

General Description

The TS19453 is a PWM high efficiency programmable current LED driver with PWM dimming control IC. It allows

efficient operation of LED strings from voltage source ranging up to 400VDC. It includes an internal high voltage

switching MOSFET controlled with fixed off-time of approximately 12µS.

The LED string is driven at constant current, thus providing constant light output and enhanced reliability. The

output current is internally programmable up to 50mA. The peak current control scheme provides good regulation

of the output current throughout the universal AC line voltage range of 85~264VAC or DC input voltage of

20~400V

Features

Typical Application Circuit

●

Adjust constant output current up to 50mA(typ)

Universal 85~264VAC operation

Over temperature protection with hysteresis

PWM dimming

Fixed off-time buck converter

Internal 475V power MOSFET

Application

●

Decorating LED lighting

●

LED lamps with AC or DC operation.

Ordering Information

Part No.

Package

Packing

TS19453CS RLG

SOP-8

2.5Kpcs/13” Reel

Note: “G” denote for Halogen Free Product

Absolute Maximum Rating

Parameter

Symbol

V_INto GND

V_DDto GND

Limit

~ +475

Unit

Input Voltage Range

VDD to GND

~ 9

PMWD, Rsense to GND

Power Dissipation @ T_A=25ºC

Operating Ambient Temperature

Storage Temperature Range

Thermal Resistance – Junction to Ambient

~ V_DD+0.3

Internally Limited

-40 to +85

-65 to +150

160

P_D

T_OPR

T_STG

Rθ_JA

ºC

^oC

^oC/W

Note: Stresses beyond those listed under ”Absolute Maximum Ratings” may cause permanent damage to the

device. These are stress rating only, and functional operation of the device at these or any other conditions beyond

those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum

rating conditions for extended periods may affect device reliability.

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Preliminary

AC/DC Programmable Current WLED Driver

w/PWM Dimming Control

TS19453

Electrical Specifications (Ta = 25^oC, V_DRAIN= 50V, unless otherwise noted)

Function Parameter

Internal Regulator

Symbol

Test Conditions

Min

Typ

Max Units

Internally Regulated Voltage

Drain Supply Voltage

Undervoltage Lockout Threshold

Undervoltage Lockout Hysteresis

Supply Current

V_DD

V_DRAIN

UVLO

∆UVLO

I_DD

4.8

7.5

400

V_DDrising

V_DDfalling

200

µA

V_DD(EXT)=8.0V

500

Output (Drain)

Breakdown Voltage

V_BR

R_DSON

I_SAT

Note 1

475

200

Ω

On Resistance

I_DRAIN=50mA

MOSFET Saturation current

Current Sense Comparator

Threshold Voltage

100

150

V_TH

Note 1

0.43

200

300

0.53

400

650

Leading edge Blanking delay

Minimum Turn On-Time

Off-Time Generator

Turn On-Time

T_BLANK

T_ON(min)

Note 1,2

T_OFF

µS

PWMD

High voltage

Low voltage

VPWMD=5V

2.0

PWMD Input Voltage

V_PWMD

R_PWMD

0.8

300

PWMD Pull Down Resistance

100

Ω

Note 1: The specification which apply over the full operating ambient temperature range of -40ºC<T_A<+85ºC

2: Guaranteed by design

Block Diagram

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AC/DC Programmable Current WLED Driver

w/PWM Dimming Control

TS19453

Function Description

The TS19453 is a PWM peak current controller for controlling a buck converter topology in continuous conduction

mode (CCM). The output current is of converter that can be programmed by a single external resistor (Rsense), for

the purpose of driving a string of LED, an external enable input (PWMD) is provided that can be utilized for PWM

dimming of an LED string.

When the input voltage of 20~400V appears at the Drain pin, the internal high-voltage linear regulator seeks to

maintain a voltage of 7.5VDC at the VDD pin. Until this voltage exceeds the internally programmed under-voltage

threshold, the output switching MOSFET is non-conductive. When the threshold is exceeded, the integrated high-

voltage switch turns on, pulling the Drain low, A 200mV hysteresis is incorporated with the undervoltage

comparator to prevent oscillation.

When the voltage at Rsense exceeds 0.47V(typ), the switch turns off and the Drain output becomes high

impedance, at the same time, a one shot circuit is activated that determines the off-time of the switch.

A “blanking” delay of 300nS is provided that presents false triggering of the current sense comparator due to the

leading edge spike caused by circuit parasitic.

Application Information

The TS19453 is specifically designed for driving multi LED strings. It can be operated from either universal AC line

range of 85~264VAC or 20~400VDC, and drives up to tens of high brightness LEDs. All LEDs can be run in series

and this device regulates at constant current, yielding uniform illumination.

Selecting L1 and D1

There is a certain trade-off to be considered between optimal sizing of the output inductor L1 and the tolerated

output current ripple. The required value of L1 is inversely proportional to the ripple current ∆I_Oin it.

L1 = (V_Ox T_OFF) / ∆I_O

V_Ois the forward voltage of the LED string. T_OFFis the off-time of the TS19453. The output current in the LED string

(I_O) is calculated as:

I_O= (Vth / Rsense) – (∆I_O/ 2)

Where I_THis the current sense comparator threshold, and Rsense is the current sense resistor. The ripple current

introduces a peak-to-average error in the output current setting that needs to be accounted for. Due to constant off-

time control technique used in the TS19453, the ripple current is independent of the input AC or DC line voltage

variation. Therefore, the output current will remain unaffected by the varying input voltage.

Adding a filter capacitor across the LED string can reduce the output current ripple even further, thus permitting a

reduced value of L1. However, one must keep in mind that the peak-to-average current error is affected by the

variation of T_OFF. Therefore, the initial output current accuracy might be sacrificed at large ripple current in L1.

Another important aspect of designing an LED driver with TS19453 is related to certain parasitic elements of the

circuit, including distributed coil capacitance of L1, junction capacitance and reverse recover of the rectifier diode

D1, capacitance of the PCB traces C_PCBand output capacitance C_DRAINof the controller itself. These parasitic

elements affect the efficiency of the switching converter and could potentially cause false triggering of the current

sense comparator if not properly managed. Minimizing these parasitic is essential for efficient and reliable

operation.

Coil capacitance of inductors is typically provided in the manufacturer’s data books either directly or in terms of the

self-resonant frequency (SRF).

SRF = 1 / (2π√(L * C_L))

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AC/DC Programmable Current WLED Driver

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TS19453

Application Information (Continue)

L is the inductance value, and C_Lis the coil capacitance. Charging and discharging this capacitance every

switching cycle causes high-current spikes in the LED string. Therefore, connecting a small capacitor C_O(~100nF)

is recommended to bypass these spikes.

Using an ultra-fast rectifier diode for D1 is recommended to achieve high efficiency and reduce the risk of false

triggering of the current sense comparator. Using diodes with shorter reverse recovery time t_rrand lower junction

capacitance C_Jachieves better performance. The reverse voltage rating V_Rof the diode must be greater than the

maximum input voltage of LED lamps.

The total parasitic capacitance present at the Drain pin of the TS19453 can be calculated as:

C_P= C_DRAIN+ C_PCB+ CL + C_J

When the switching MOSFET turns on, the capacitance C_Pis discharged into the Drain pin of the IC. The discharge

current is limited to about 50mA typically. However, it may become lower at increased junction temperature. The

duration of the leading edge current spike can be estimated as:

T_PSIKE= ((V_INx C_P) / (I_SAT)) + t_rr

In order to avoid false trigger of the current sense comparator, C_Pmust be minimized in accordance with the

following expression.

C_P=< (Isat * ( T_BLANK(min)- t_rr)) / Vin(max)

When T_BLANK(min)is the minimum blanking time of 200nS, and Vin(max) is the maximum instantaneous input voltage.

Estimating Power Loss

Discharging the parasitic capacitance C_Pin the the Drain output of TS19453 is responsible for the bulk of the

switching power loss. It can be estimated using as:

P_SWITCH= ((C_P* V_IN²/ 2 ) + (V_IN* I_SAT* t_rr)) * F_S

F_Sis the switching frequency and is the saturated Drain current of TS19453, the switching loss is the greatest at

the maximum input voltage.

Disregarding the voltage drop at TS19453 and D1, the switching frequency is given as

F_S= (V_IN- V_OUT) / (V_IN* T_OFF

)

When the TS19453 is powered from full wave rectified AC input, the swithching power loss can be estimated as:

P_SWITCH= 1 / (2 * T_OFF) * ((V_AC* C_P+ 2 * I_SAT* t_rr) * (V_AC- V_OUT)))

When the TS19453 is powered from DC input voltage, conduction power loss can be estimated as:

P_COND= (D * I_OUT²* R_ON) + I_DD* V_IN* (1 – D)

EMI Filter

As with all off-line converters, selecting an input filter is critical to obtaining good EMI. A switching side capacitor,

albeit of small value, is necessary in order to ensure low impedance to the high frequency switching currents of the

converter. As a rule of thumb, this capacitor should be approximately 0.1~0.2µF/W of LED output power.

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AC/DC Programmable Current WLED Driver

w/PWM Dimming Control

TS19453

Typical Application Circuit

Typical Application Circuit for Universal 85~264VAC LED Lamps Driver (Non-Isolation)

15pcs LED (VLED=49.5V), LED current 50mA

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w/PWM Dimming Control

TS19453

SOP-8 Mechanical Drawing

SOP-8 DIMENSION

MILLIMETERS

INCHES

MIN

DIM

MIN

4.80

3.80

1.35

0.35

0.40

MAX

5.00

4.00

1.75

0.49

1.25

MAX.

0.196

0.157

0.068

0.019

0.049

0.189

0.150

0.054

0.014

0.016

1.27BSC

0.05BSC

0.10

0º

0.25

7º

0.004

0º

0.009

7º

5.80

0.25

6.20

0.50

0.229

0.010

0.244

0.019

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w/PWM Dimming Control

TS19453

Notice

Specifications of the products displayed herein are subject to change without notice. TSC or anyone on its behalf,

assumes no responsibility or liability for any errors or inaccuracies.

Information contained herein is intended to provide a product description only. No license, express or implied, to

any intellectual property rights is granted by this document. Except as provided in TSC’s terms and conditions of

sale for such products, TSC assumes no liability whatsoever, and disclaims any express or implied warranty,

relating to sale and/or use of TSC products including liability or warranties relating to fitness for a particular purpose,

merchantability, or infringement of any patent, copyright, or other intellectual property right.

The products shown herein are not designed for use in medical, life-saving, or life-sustaining applications.

Customers using or selling these products for use in such applications do so at their own risk and agree to fully

indemnify TSC for any damages resulting from such improper use or sale.

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TS19453 [TSC]

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