WS9227_技术文档

WS9227^{ProductDescription}

High Precision PSR Constant Current LED Driver

Features

Description



Built-in 650V Power MOSFET

The WS9227 is a high precision primary-side feedback

Constant current control without secondary sense and

feedback circuit.

and regulation controller for LED lighting, it operates in

constant current control mode and is designed to work in

inductor current discontinuous conduction mode and

especially suitable for fly back convertor under universal input.

The output power of system is recommended to less than

24W.



No Auxiliary winding for sensing and supplying

Ultra low operating current to improve efficiency

Universal input voltage

±5% LED current accuracy

LED short and open circuit protection

VCC under-voltage protection

The WS9227integrates 650V power MOSFET. Since

adopting primary sense and feedback control technology, the

secondary sense and feedback circuit is eliminated. The loop

compensation components are also removed while

maintaining stability overall operating conditions. The

operating current is very low, and it doesn’t need the auxiliary

winding for sensing the output current and supplying the chip.

The low component counts and small system size are

realized.

Over temperature protection

Available in DIP-8 package and SOP-7 package

Applications



LED bulb, spot light

Other LED lighting

Since using the proprietary high accurate current sense

method, theWS9227 realizes ±5% accuracy of LED current

along with excellent line and load regulation.

The WS9227 offers rich protection functions including

LED open/short circuit protection, over-temperature

protection, VCC under voltage protection.

Typical Application

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WS9227^{ProductDescription}

Pin Configuration and Marking Information

The WS9227 is available in DIP-8 package, the top marking is shown as below:

WS9227D8P

A：Product Code

X：Internal Code

BCY：Internal Code For QC

YMX：D/C

Pin Definition

Name

Pin No.

Description

GND

1

Ground

Current sense. This pin connects a current sense resistor to GND to detect the primary

current of transformer.

CS

2

NC

VCC

3/5

4

No connection, must be floated

Power supply

DRAIN

6,7,8

Internal high voltage MOSFET Drain

Internal Block Diagram

Ordering Information

Package

Marking

Part Number

8-Pin DIP-8, Pb-free

WS9227D8P

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WS9227^{ProductDescription}

Recommended Operation Conditions

Maximum output

power

Part Number

Package

Input voltage

175VAC-264VAC

90VAC-264VAC

<50W

<36W

WS9227

DIP8

Absolute Maximum Ratings

symbol

Icc_max

Drain

CS

paramete

Range

unit

mA

V

VCC pin maximum sink current

Internal HV MOSFET drain voltage

Current sense pin input voltage

Operating junction temperature

Storage temperature range

2.5

-0.3~650

-0.3~7

165

V

TJ

℃

TSTG

-55~165

℃

Note 1: Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device.

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WS9227^{ProductDescription}

Electrical Characteristics (Unless otherwise specified, VCC=8V and TA =25 ℃)

Symbol

Parameter

Conditions

Min

Typ

Max

Units

Supply Voltage Section

V_{CC_Clamp}

UVLO_{_off}

UVLO_{_on}

I_ST

VCC clamp voltage

1mA

17.8

14.3

9

18.8

15.3

9.5

19.8

16.3

10

V

Turn-off threshold Voltage

Turn on threshold Voltage

VCC start up current

V

VCC= 13V

150

205

140

250

uA

I_OP

VCC operating current

Fop=70KHz

Current Sense Section

Threshold voltage for peak

V_{CS_TH}

390

400

410

mV

current limit

Leading edge blanking

time for current sense

T_LEB

350

200

ns

T_DELAY

Switch off delay time

Internal driver Section

T_{off_max}

T_{off_min}

T_{on_max}

Maximum Off Time

310

3.5

us

Minimum Off Time

Maximum On Time

100

Output OVP Threshold

Time

T_{ons_OVP}

7

us

MOSFET Section

Static drain-source

on-resistance

R_{DS_ON}

0.96

1.2

10

Ω

V

Drain-source breakdown

voltage

BV_DSS

650

Drain-source leakage

current

I_DSS

uA

Over Temperature Protection

Thermal Regulation

Temperature

TREG

150

℃

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WS9227ProductDescription

Application Information

Operating Switching Frequency

The WS9227 is a high performance power switch

specially designed for LED lighting, with patent constant

current control technology. The WS9227integrates a 650V

power MOSFET. The accurate LED current can be realized

without opto-coupler, TL431 feedback circuit and auxiliary

winding while minimizing the external component count,

lowering the total bill of material cost.

The WS9227 is designed to work in discontinuous

conduction mode and no external loop compensation

component is required while maintaining stability. The

maximum duty cycle is limited to 42%. The maximum

switching frequency at normal operation is suggested to set

around 65KHz~70KHz. If the maximum frequency is set too

high, it will affect the number of maximum series LED lamps.

If set too low, the LED open circuit voltage will be too high.

The maximum and minimum switching frequency is

limited in WS9227 to ensure the stability of system.

The switching frequency can be set by the formula:

Start Up

The start-up current inWS9227 is designed to as low as

205uA. The VCC capacitor will be charged through the

start-up resistor when the system is powered on. Once the

VCC voltage reaches the start-up threshold, the WS9227

will start to switch. TheWS9227 integrates a 19V zener for

VCC clamping. Due to the ultra-low operating current, the

auxiliary winding is not needed to supply the IC.

Np²V_LED

f 

8 Ns² Lp I_LED

Where, LP is the primary winding inductance of

transformer.

Constant Current Control

Protection Function

Cycle-by-Cycle current sense is adopted in WS9227,

the CS is connected to the current sense comparator, and

the voltage on CS will be compared with the internal 400mV

reference voltage, the MOSFET will be switched off when

the voltage on CS reaches the threshold. The output of the

comparator includes a 350ns leading edge blanking time.

The primary peak current is given by:

The WS9227 has integrated rich protection functions,

LED open/short protection, CS resistor short circuit

protection, VCC under voltage protection, over temperature

protection, and so on. When the LED is open circuit, it will

trigger over-voltage protection logic and latch, the system

stops switching immediately.

When the LED short circuit is detected the system

works at low frequency (Fop=3KHz), so the power

consumption is low. After the system enters into fault latch

condition, the VCC voltage will fall until it reaches UVLO

threshold. Then the system will re-start again. If the fault

condition is removed, the system will recover to normal

operation.

400

I_{P_PK}



(mA)

R_CS

The current in LED can be calculated by the equation:

I_{P_PK}

N_P

N_S

I_OUT





4

Where,

PCB Layouts

NP: primary winding turns of transformer

NS: secondary winding turns of transformer

IP_PK: peak current in MOSFET

The following rules should be followed in WS9227 PCB

layout.

Bypass Capacitor

The bypass capacitor on VCC should be as close as

possible to the VCC pin and GND pin.

Ground Path

Power MOSFET

The WS9227integrates a 650V power N-MOSFET. It

can minimize the external component count and reduce the

BOM cost and PCB size.

The power ground path for current sense should be

short, and the power ground path should be separated from

small signal ground path before the negative of the bulk

capacitor.

The WS9227 uses DIP-8 package. The recommended

system output power is below 24W in universal input

(90Vac~265Vac) application.

The Area of Power Loop

The area of main current loop should be as small as

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WS9227ProductDescription

possible to reduce EMI radiation, such as the primary

current loop, the snubber circuit and the secondary rectifying

loop.

NC Pin

The NC pin must be left floating to satisfy the

requirement of creepage distance.

Drain pin

To increase the copper area of drain for thermal

consideration.

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WS9227ProductDescription

Package Information

DIP8Package Outline Dimensions

D2

θ2

1

θ

3

θ

D1

A2

A

D

A3

A4

A5

A1

Winsemi

Dimensions in Millimeters

Dimensions in Inches

Symbol

Min

9.00

6.10

3.0

Max

9.50

6.60

3.4

Min

Max

A

0.354

0.240

0.118

0.058

0.016

0.096

0.374

0.260

0.134

0.062

0.021

0.104

B

C

A1

A2

A3

A4

A5

C1

C2

C3

C4

D

1.474

0.41

2.44

1.574

0.53

2.64

0.51TYP

0.99TYP

0.02TYP

0.04TYP

6.6

7.30

0.260

0.287

0.50TYP

0.02TYP

3.00

1.47

7.62

0.24

3.40

1.65

9.3

0.118

0.058

0.300

0.009

0.134

0.065

0.366

0.013

D1

D2

0.32

7.62TYP

0.3TYP

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WS9227ProductDescription

NOTE:

1.We strongly recommend customers check carefully on the trademark when buying our product, if there is any

question, please don't be hesitate to contact us.

2.Please do not exceed the absolute maximum ratings of the device when circuit designing.

3.Winsemi Microelectronics Co., Ltd reserved the right to make changes in this specification sheet and is

subject to change without prior notice.

CONTACT:

Winsemi Microelectronics Co., Ltd.

ADD:Futian District, ShenZhen Tian An Cyber Tech Plaza two East Wing 1002

Post Code : 518040

Tel : +86-755-8250 6288

FAX : +86-755-8250 6299

Web Site : www.winsemi.com

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型号：	WS9227
厂家：	ETC
描述：	High Precision PSR Constant Current LED Driver
文件：	总8页 (文件大小：544K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

WS9227 [ETC]

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