LM3699 [TI]

高效白光 LED 驱动器;


型号：	LM3699
厂家：	TEXAS INSTRUMENTS
描述：	高效白光 LED 驱动器驱动驱动器
文件：	总24页 (文件大小：939K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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LM3699

ZHCSCB2A –JANUARY 2014–REVISED MARCH 2014

LM3699 高效白光发光二极管 (LED) 驱动器

1 特性

3 说明

•

驱动并联高压 LED 灯串用于显示或键区照明

LM3699 是一款三灯串，高效、由 PWM 控制的电源，

用于智能手机的显示背光或键区 LED。具有集成

1A，40V MOSFET 的高压电感升压转换器为三个串联

LED 灯串供电。升压输出自动调节到 LED 正向电

压，以最大限度地减少净空电压并有效地改进 LED 效

率。

升压转换器效率高达 90%

四个用户可选满量程电流设置

(20.2mA，18.6mA，17.0mA，15.4mA)

•

快速调光使能端子 (ILOW)

简单脉宽调制 (PWM) 占空比控制

24V 过压保护阀值

ILOW 端子提供一个在照相机闪光灯运行时快速减少

LED 亮度的方法。

固定 1MHz 开关频率

集成型 1A/40V 金属氧化物半导体场效应晶体管

(MOSFET)

LM3699 具有集成过压、过流和过热保护。

•

三个灌电流端子

此器件在 2.7V 至 5.5V 的输入电压范围和 -40°C 至

85°C 的温度范围内运行。

自适应升压输出至 LED 电压

热关断保护

29mm²总体解决方案尺寸

器件信息

订货编号

封装

封装尺寸

2 应用范围

芯片级球状引脚栅格

阵列 (DSBGA) (12)

LM3699YFQ

1.64mm x 1.29mm

•

用于智能手机照明的电源

显示或键区照明

在使用 10µH 电感器时，升压效率与 V_IN之间的关系

简化电路原理图

V_OUTup to 24V

90%

88%

86%

84%

82%

80%

78%

V_IN

C_IN

C_OUT

LM3699

GND

OVP

IS1

IS0

HVLED1

HVLED2

HVLED3

3s3p

4s3p

5s3p

6s3p

76%

74%

72%

70%

ILOW

RST

ILOW

HWEN

PWM

2.5

3.5

4.5

5.5

VIN (V)

C012

PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not necessarily include testing of all parameters.

English Data Sheet: SNVS821

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7.3 Feature Description................................................... 8

7.4 Device Functional Modes.......................................... 9

Application and Implementation ........................ 10

8.1 Application Information............................................ 10

8.2 Typical Application .................................................. 10

Power Supply Recommendations...................... 15

特性.......................................................................... 1

应用范围................................................................... 1

说明.......................................................................... 1

修订历史记录 ........................................................... 2

Terminal Configuration and Functions................ 3

Specifications......................................................... 4

6.1 Absolute Maximum Ratings ...................................... 4

6.2 Handling Ratings....................................................... 4

6.3 Recommended Operating Conditions....................... 4

6.4 Thermal Information.................................................. 4

6.5 Electrical Characteristics .......................................... 5

6.6 Typical Characteristics.............................................. 7

Detailed Description .............................................. 8

7.1 Overview ................................................................... 8

7.2 Functional Block Diagram ......................................... 8

10 Layout................................................................... 16

10.1 Layout Guidelines ................................................ 16

10.2 Layout Example .................................................... 18

11 器件和文档支持 ..................................................... 19

11.1 器件支持................................................................ 19

11.2 Trademarks........................................................... 19

11.3 Electrostatic Discharge Caution............................ 19

11.4 Glossary................................................................ 19

12 机械封装和可订购信息 .......................................... 19

4 修订历史记录

Changes from Original (January 2014) to Revision A

Page

•

已更改更改为全新的 TI 数据表格式：添加处理额定值表以及器件和文档支持部分 ............................................................... 1

Added new scope shot ........................................................................................................................................................ 14

LM3699

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5 Terminal Configuration and Functions

DSBGA (YFQ)

12 Terminals

Top View

Bottom View

Terminal Functions

TERMINAL

DESCRIPTION

NUMBER

NAME

PWM

PWM brightness control input. PWM is a high-impedance input and cannot be left floating.

Current select input 1. This is a high-impedance input and cannot be left floating. IS0 can be connected to

IN or GND.

IS0

Hardware enable input. Drive this terminal high to enable the device. Drive this terminal low to force the

device into a low-power shutdown. HWEN is a high-impedance input and cannot be left floating.

HWEN

HVLED1

Input terminal to high-voltage current sink 1 (24 V max). The boost converter regulates the minimum of

HVLED1, HVLED2, and HVLED3 to V_HR

Current select input 2. This is a high-impedance input and cannot be left floating. IS1 can be connected to

IN or GND.

IS1

Input voltage connection. Bypass IN to GND with a minimum 2.2-µF ceramic capacitor.

Input terminal to high-voltage current sink 2 (24 V max). The boost converter regulates the minimum of

HVLED2

HVLED1, HVLED2, and HVLED3 to V_HR

Low level current enable. Drive this terminal high to reduce LED current by approximately 95%. ILOW is a

high-impedance input and cannot be left floating. If not used connect to GND.

ILOW

GND

Ground.

Input terminal to high-voltage current sink 3 (24 V max). The boost converter regulates the minimum of

HVLED3

HVLED1, HVLED2, and HVLED3 to V_HR

Overvoltage sense input. Connect OVP to the positive terminal of the inductive boost output capacitor

(C_OUT).

OVP

Drain connection for the internal NFET. Connect SW to the junction of the inductor and the Schottky diode

anode.

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6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)

(1)(2)

MIN

MAX

UNIT

V_INto GND

−0.3V

V_SW, V_OVP, V_HVLED1, V_HVLED2, V_HVLED3to GND

V_IS1, V_IS0, V_ILOW, V_PWMto GND

V_HWENto GND

Continuous power dissipation

Maximum lead temperature (soldering)

Internally Limited

260 (peak)

150

°C

Junction temperature (T_J-MAX

)

(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings

only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended

Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

(2) All voltages are with respect to the potential at the GND terminal.

6.2 Handling Ratings

MIN

MAX

150

UNIT

°C

Storage temperature range

Human body model (HBM)⁽²⁾

Charged device model (CDM)⁽³⁾

−65

2.0

ESD Ratings⁽¹⁾

1500

(1) Electrostatic discharge (ESD) to measure device sensitivity and immunity to damage caused by assembly line electrostatic discharges in

to the device.

(2) Level listed above is the passing level per ANSI, ESDA, and JEDEC JS-001. JEDEC document JEP155 states that 500-V HBM allows

safe manufacturing with a standard ESD control process.

(3) Level listed above is the passing level per EIA-JEDEC JESD22-C101. JEDEC document JEP157 states that 250-V CDM allows safe

manufacturing with a standard ESD control process.

6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)

MIN

2.7

MAX

5.5

UNIT

V_INto GND

V_SW, V_OVP, V_HVLED1, V_VHLED2, V_VHLED3to GND

(1)(2)

Junction temperature (T_J)

−40

125

°C

(1) Internal thermal shutdown circuitry protects the device from permanent damage. Thermal shutdown engages at T_J= 140°C (typ) and

disengages at T_J= 125°C (typ).

(2) In applications where high power dissipation and/or poor package thermal resistance is present, the maximum ambient temperature may

have to be derated. Maximum ambient temperature (T_A-MAX) is dependent on the maximum operating junction temperature (T_J-MAX-OP

125°C), the maximum power dissipation of the device in the application (P_D-MAX), and the junction-to ambient thermal resistance of the

part/package in the application (θ_JA), as given by the following equation: T_A-MAX= T_J-MAX-OP– (θ_JA× P_D-MAX).

6.4 Thermal Information

DSBGA

THERMAL METRIC⁽¹⁾

UNIT

(12 TERMINALS)

R_θJA

Junction-to-ambient thermal resistance

°C/W

(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

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6.5 Electrical Characteristics

Limits apply over the full operating ambient temperature range (−40°C ≤ T_A≤ 85°C) and V_IN= 3.6V, unless otherwise

specified.⁽¹⁾⁽²⁾

SYMBOL

General

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNIT

2.7 V ≤ V_IN≤ 5.5 V, HWEN = GND

3.0

I_SHDN

Shutdown current

µA

°C

2.7 V ≤ V_IN≤ 5.5 V, HWEN = GND,

T_A= 25°C

Thermal shutdown

Hysteresis

140

T_SD

Boost Converter

2.7 V ≤ V_IN≤ 5.5 V, ILOW = GND,

IS0 = IS1 = VIN,

18.38

22.02

PWM Duty Cycle = 100%

2.7 V ≤ V_IN≤ 5.5 V, ILOW = GND,

IS0 = IS1 = VIN,

PWM Duty Cycle = 100%

T_A= 25°C

20.2

ILOW = GND, IS0 = IS1 = VIN,

PWM Duty Cycle = 100%

T_A= 25°C

18.7

21.58

Output current

regulation (HVLED1,

HVLED2, HVLED3)

I_HVLED(1/2/3)

ILOW = GND, IS0 = IS1 = VIN,

PWM Duty Cycle = 100%,

T_A= 25°C

3.0 V ≤ V_IN≤ 4.5 V, ILOW = GND,

IS0 = IS1 = VIN,

PWM Duty Cycle = 100%

T_A= 25°C

18.63

3.0 V ≤ V_IN≤ 4.5 V, ILOW = GND,

IS0 = IS1 = VIN,

PWM Duty Cycle = 100%

T_A= 25°C

20.2

2.7 V ≤ V_IN≤ 5.5 V, ILOW = GND,

IS0 = IS1 = VIN,

PWM Duty Cycle = 100%

–2.5%

–2%

2.5%

1.7%

HVLED matching

(HVLED1 to HVLED2

ILOW = GND, IS0 = IS1 = VIN,

I_{MATCH_HV}

or HVLED2 to HVLED3 PWM Duty Cycle = 100%, T_A=

or HVLED1 to

HVLED3)

25°C

(3)

3.0 V ≤ V_IN≤ 4.5 V, ILOW = GND,

IS0 = IS1 = VIN,

PWM Duty Cycle = 100%

–2.5%

2.5%

275

ILOW = GND, IS0 = IS1 = VIN,

PWM Duty Cycle = 100%,

T_A= 25°C

Regulated current sink

headroom voltage

V_{REG_CS}

400

I_LED= 95% of nominal, ILOW =

GND, IS0 = IS1 = VIN, PWM Duty

Cycle = 100%

Minimum current sink

headroom voltage for

HVLED current sinks

V_{HR_MIN}

I_LED= 95% of nominal, ILOW =

GND, IS0 = IS1 = VIN, PWM Duty

Cycle = 100%

190

0.3

T_A= 25°C

NMOS switch on

resistance

R_DSON

I_SW= 500 mA, T_A= 25°C

T_A= 25°C

Ω

880

1120

NMOS Switch Current

Limit

I_{CL_BOOST}

1000

(1) All voltages are with respect to the potential at the GND terminal.

(2) Minimum (Min) and Maximum (Max) limits are verified by design, test, or statistical analysis. Typical (Typ) numbers are not verified, but

do represent the most likely norm. Unless otherwise specified, conditions for typical specifications are: V_IN= 3.6 V and T_A= 25°C.

(3) LED current sink matching in the high-voltage current sinks (HVLED1, HVLED2, and HVLED3) is given as the maximum matching value

between any two current sinks, where the matching between any two high-voltage current sinks (X and Y) is given as (I_HVLEDX(or

I_HVLEDY) - I_AVE(X-Y))/(I_AVE(X-Y)) x 100.

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Electrical Characteristics (continued)

Limits apply over the full operating ambient temperature range (−40°C ≤ T_A≤ 85°C) and V_IN= 3.6V, unless otherwise

specified.⁽¹⁾⁽²⁾

SYMBOL

PARAMETER

TEST CONDITIONS

ON threshold, 2.7 V ≤ V_IN≤ 5.5 V

ON threshold, T_A= 25°C

Hysteresis, T_A= 25°C

2.7 V ≤ V_IN≤ 5.5 V

MIN

TYP

MAX

UNIT

Output overvoltage

protection

V_OVP

0.7

900

1100

f_SW

Switching frequency

Maximum duty cycle

kHz

T_A= 25°C

1000

94%

D_MAX

T_A= 25°C

HWEN Input

Input logic low

Input logic high

2.7 V ≤ V_IN≤ 5.5 V

0.4

V_IN

V_HWEN

1.2

PWM Input

V_{PWM_L}

Input logic low

Input logic high

2.7 V ≤ V_IN≤ 5.5 V

0.4

V_IN

V_{PWM_H}

1.31

Minimum PWM input

pulse detected

t_PWM

2.7 V ≤ V_IN≤ 5.5 V

0.75

µs

IS1, IS0, ILOW Inputs

V_IL

V_IH

Input logic low

Input logic high

2.7 V ≤ V_IN≤ 5.5 V

0.4

V_IN

1.29

Internal POR Threshold

V_INramp time = 100 μs

1.7

2.1

POR reset release

voltage threshold

V_POR

V_INramp time = 100 μs

T_A= 25°C

1.9

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6.6 Typical Characteristics

0.5

0.45

0.4

2.5

1.5

0.35

0.3

0.5

VIN=2.7

VIN=3.6

VIN=5.5

VIN=3.6

VIN=2.7

0.25

0.2

-50 -25

75 100 125

-50 -25

75 100 125

Temperature (C)

C022

C024

Figure 1. Rdson vs Temperature

Figure 2. I_QShutdown vs Temperature

300

250

200

150

100

1.5

0.5

VIN=2.7

VIN=3.6

VIN=5.5

VIN=3.6

-50 -25

75 100 125

-50 -25

75 100 125

Temperature (C)

C027

C023

Figure 3. V_{HR_MIN}vs Temperature

Figure 4. POR Threshold vs Temperature

1.4

1.2

1.4

1.2

0.8

0.6

0.4

0.2

0.8

0.6

0.4

0.2

VIN=5.5

VIN=3.6

VIN=2.7

VIN=5.5

VIN=3.6

VIN=2.7

-50 -25

75 100 125

-50 -25

75 100 125

Temperature (C)

C025

C026

Figure 5. PWM V_IHvs Temperature

Figure 6. PWM V_ILvs Temperature

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7 Detailed Description

7.1 Overview

The LM3699 provides power for three high-voltage LED strings. The high-voltage LED strings are powered from

an integrated boost converter. The LED current is directly controlled by a Pulse Width Modulation (PWM) input.

7.2 Functional Block Diagram

Overvoltage

Protection

OVP

Boost Converter

Hardware Enable,

Reference, and

Thermal Shutdown

HWEN

PWM

Current Limit

Switch Frequency

High Voltage

Current Sinks

LPF

HVLED1

HVLED2

HVLED3

Full-Scale

Current

Control

IS1

IS0

Quick

Dimming

Control

GND

ILOW

7.3 Feature Description

7.3.1 PWM Input

The active high PWM input is filtered by an internal low-pass filter, then converted to an analog control voltage to

set the current level on the current sink outputs. The PWM input is high-impedance and cannot be left floating.

7.3.1.1 PWM Input Frequency Range

The usable input frequency range for the PWM input is governed on the low end by the cutoff frequency of the

internal low-pass filter (540 Hz, Q = 0.33) and on the high end by the propagation delays through the internal

logic. For frequencies below 2 kHz the current ripple begins to become a larger portion of the DC LED current.

Additionally, at lower PWM frequencies the boost output voltage ripple increases, causing a non-linear response

from the PWM duty cycle to the average LED current due to the response time of the boost. For the best

response of current vs. duty cycle, the PWM input frequency should be kept between 2 kHz and 100 kHz.

7.3.1.2 PWM Low Detect

The LM3699 incorporates a feature to detect when the PWM input duty cycle is near zero. This feature requires

that the minimum PWM input pulse width be greater than t_PWM(see Electrical Characteristics ). A PWM input

pulse width less than t_PWMcan result in the current sink outputs turning on and off resulting in flicker on the

LEDs.

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Feature Description (continued)

7.3.2 HWEN Input

HWEN is the global hardware enable to the LM3699 and must be driven high to enable the device. HWEN is a

high-impedance input, so it cannot be left floating. When HWEN is driven low the LM3699 is placed in shutdown,

and the boost converter and all the HVLED current sinks are turned off.

7.3.3 Current Select Inputs (IS1 And IS0)

The current select inputs IS1 and IS0 select the maximum full-scale current (ifs). These digital inputs are static

and must not change state when HWEN > V_IL. IS1 and IS0 are high-impedance inputs so they cannot be left

floating. The terminals IS1 and IS0 can be connected directly to IN or GND and do not require an external

pullup/pulldown resistor. The full-scale current is set according to Table 1:

Table 1. Full-Scale Current vs Current Select Inputs IS1 and IS0

IS1

IS0

FULL-SCALE CURRENT (ifs) (mA)

15.4

17.0

18.6

20.2

7.3.4 ILOW Input

The ILOW feature provides a way to quickly reduce the LED current. This feature can be used to dim the LCD

backlight during camera flash operation without changing the PWM duty cycle. ILOW is a high-impedance input

so it cannot be left floating. When ILOW is driven high, the high-voltage current sink outputs are approximately

equal to (ifs x D_PWMx 5%). When ILOW is driven low, the high-voltage current sinks are a function of the full-

scale current setting and the PWM input duty cycle. If ILOW is not required the input should be connected to

GND.

7.3.5 Thermal Shutdown

The LM3699 contains a thermal shutdown protection. In the event the die temperature reaches 140°C (typ), the

boost converter and current sink outputs shut down until the die temperature drops to typically 125°C.

7.4 Device Functional Modes

7.4.1 Operation with an Unused Current Sink

If one of the current sink outputs is not connected to a LED string the terminal must be connected to V_IN. This

ensures that the boost converter regulates the headroom voltage on the highest voltage LED string.

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8 Application and Implementation

8.1 Application Information

Table 2. Recommended Components

CURRENT/VOLTAGE

RATING (RESISTANCE)

COMPONENT MANUFACTURER

VALUE

PART NUMBER

SIZE (mm)

TDK

10 µH

1.0 µF

VLF302512MT-100M

C2012X5R1E105

C1005X5R1A225

NSR0240V2T1G

2.5 x 3.0 x 1.2

0805

620 mA/0.25 Ω

25V

COUT

CIN

TDK

2.2 µF

0402

10V

Diode

On-Semi

Schottky

SOD-523

40V, 250 mA

8.2 Typical Application

VIN = 2.7 - 5.5 V

VIN

CIN

VLF302512MT-100M

2.2µF

10µH

LM3699YFQ

NSR0240V2T1G

40V

GND

VOUT

OVP

IS1

IS0

HWEN

COUT

1µF

HWEN

PWM

HVLED1

HVLED2

HVLED3

LED1

LED2

LED3

PWM

ILOW

GND

ILOW

GND

Figure 7. LM3699 Simplified Schematic

8.2.1 Design Requirements

Table 3. Design Parameters

DESIGN PARAMETER

Full-scale current setting

Minimum input voltage

EXAMPLE VALUE

20.2 mA

2.7 V

6s3p

LED series/parallel configuration

LED maximum forward voltage (V_f)

Efficiency

3.5 V

75%

8.2.2 Detailed Design Procedure

8.2.2.1 Step-by-Step Design Procedure

The designer needs to know the following:

•

Full-scale current setting

Minimum input voltage

LED series/parallel configuration

LED maximum forward voltage (V_f)

LM3699 efficiency for LED configuration

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The full-scale current setting, number of series LEDs, and minimum input voltage are needed in order to

calculate the peak input current, maximum output voltage, and maximum required output power. This information

guides the designer to determine if the LM3699 can support the required output power and make the appropriate

inductor selection for the application.

The LM3699 Boost converter output voltage (V_OUT) is calculated as follows:

number of series LEDs x V_f+ 0.4V

The LM3699 Boost converter output current (I_OUT) is calculated as follows:

number of parallel LED strings x full-scale current

The LM3699 peak input current (I_{IN_PK}) is calculated as follows:

V_OUTuI_OUT/ Minimum V_IN/ Efficiency

V_OUT 21.4 V 6u3.5 V ꢀ 0.4 V

I_OUT 0.0606 A 0.0202 A u3

! 0.640 A 21.4 V u0.0606 A / 2.7 V / 0.75

IN_PK

(1)

8.2.2.2 Maximum Output Power

The maximum output power of the device is governed by two factors: the peak current limit (I_CL= 880 mA min)

and the maximum output voltage (V_OUT). When the application causes either of these limits to be reached, it is

possible that the proper current regulation and matching between LED current strings will not be met.

8.2.2.2.1 Peak Current Limited

In the case of a peak current limited situation, when the peak of the inductor current hits the LM3699 current

limit, the NFET switch turns off for the remainder of the switching period. If this happens each switching cycle the

LM3699 regulates the peak of the inductor current instead of the headroom across the current sinks. This can

result in the dropout of the current sinks, and the LED current dropping below its programmed level.

The peak current (I_PEAK) in a boost converter is dependent on the value of the inductor, total LED current in the

boost (I_OUT), the boost output voltage (V_OUT) (which is the highest voltage LED string + V_HR), the input voltage

(V_IN), the switching frequency (ƒ_SW), and the efficiency (Output Power/Input Power). Additionally, the peak

current is different depending on whether the inductor current is continuous during the entire switching period

(CCM), or discontinuous (DCM) where it goes to 0 before the switching period ends. For CCM, the peak inductor

current is given by:

I_OUTx V_OUT

V_IN

V_INx efficiency

V_OUT

1 -

I_PEAK

V_INx efficiency

2 x ¦_SWx L

(2)

For DCM the peak inductor current is given by:

2 u I_OUT

u V_OUT- V_INu efficiency

I_PEAK

_SWu L u efficiency

(3)

To determine which mode the circuit is operating in (CCM or DCM) a calculation must be done to test whether

the inductor current ripple is less than the anticipated input current (I_IN). If ΔI_Lis less than I_IN, then the device is

operating in CCM. If ΔI_Lis greater than I_INthen the device is operating in DCM.

V_IN

I_OUTu V_OUT

V_INu efficiency

u 1 ꢀ

V_OUT

_SWu L

(4)

Typically at currents high enough to reach the LM3699 peak current limit, the device operates in CCM.

Figure 8 shows the output current derating for a 10-µH and a 22-µH inductor using 75% and 80% efficiency

estimates. These plots take equations (2) and (3) from above and plot I_OUTwith varying V_INusing a constant

peak current of 880 mA (I_{CL_MIN}) and 1-MHz switching frequency. Using these curves can help the user

understand the impact of V_IN, inductance, and efficiency on the maximum output current. A 10-µH inductor can

typically be a smaller device with lower on resistance, but the peak currents will be higher. A 22-µH inductor

provides for lower peak currents, but to match the DC resistance of a 10-µH inductor requires a larger sized

device.

LM3699

ZHCSCB2A –JANUARY 2014–REVISED MARCH 2014

www.ti.com.cn

0.062

0.061

0.06

0.059

0.058

0.057

0.056

0.055

0.054

0.053

10uH 75% Eff

10uH 80% Eff

22uH 75% Eff

VIN (V)

C021

Figure 8. Maximum Output Power Vs Inductance And Efficiency

8.2.2.2.2 Output Voltage Limited

If a output voltage limited situation occurs, when the boost output voltage hits the LM3699 OVP threshold, the

NFET turns off and stays off until the output voltage falls below the hysteresis level (typically 1 V below the OVP

threshold). This results in the boost converter regulating the output voltage to the OVP threshold, causing the

current sinks to go into dropout. The LM3699 OVP setting supports LED strings up to 6 series LEDs (V_ƒmax= 3.5

V).

8.2.2.3 Boost Inductor Selection

The boost converter operates using either a 10-µH or 22-µH inductor. The inductor selected must have a

saturation current greater than the peak operating current.

8.2.2.4 Output Capacitor Selection

The LM3699 inductive boost converter requires a 1.0-µF X5R or X7R 50V (0805 size) ceramic capacitor to filter

the output voltage. Pay careful attention to the capacitor tolerance and DC bias response. Smaller body-size 1.0-

µF ceramic capacitors or 25-V, 1.0-µF ceramic capacitors can be used, but for proper operation the degradation

in capacitance due to tolerance, DC bias, and temperature should stay above 0.4 µF. This might require placing

two devices in parallel in order to maintain the required output capacitance over the device operating range and

series LED configuration.

8.2.2.5 Schottky Diode Selection

The Schottky diode must have a reverse breakdown voltage greater than the LM3699’s maximum output voltage.

Additionally, the diode must have an average current rating high enough to handle the LM3699’s maximum

output current, and at the same time the diode peak current rating must be high enough to handle the peak

inductor current. Schottky diodes are required due to their lower forward voltage drop (0.3 V to 0.5 V) and their

fast recovery time.

8.2.2.6 Input Capacitor Selection

The LM3699 inductive boost converter requires a 2.2-µF X5R or X7R ceramic capacitor to filter the input voltage.

The input capacitor filters the inductor current ripple and the internal MOSFET driver currents during turnon of the

internal power switch.

LM3699

www.ti.com.cn

ZHCSCB2A –JANUARY 2014–REVISED MARCH 2014

8.2.3 Application Performance Plots

V_IN= 3.6 V, LEDs are WLEDs part # SML-312WBCW(A), Typical Application Circuit with L = TDK (VLF302512, 10 µH, 22 µH

where specified), Schottky = On-Semi (NSR0240V2T1G), T_A= 25°C unless otherwise specified. Efficiency is given as (V_OUT

(I_HVLED1+ I_HVLED2+ I_HVLED3))/(V_IN× I_IN), matching curves are given as (ΔI_{LED_MAX}/I_{LED_AVE}).

92%

90%

88%

86%

84%

82%

80%

78%

76%

74%

72%

70%

90%

88%

86%

84%

82%

80%

78%

76%

74%

72%

70%

3s3p

4s3p

5s3p

6s3p

3s3p

4s3p

5s3p

6s3p

2.5

3.5

4.5

5.5

2.5

3.5

4.5

5.5

VIN (V)

C013

C012

L = 22 µH

20 mA/String

L = 10 µH

20 mA/String

Figure 9. Boost Efficiency vs V_IN

Figure 10. Boost Efficiency vs V_IN

92.0%

90.0%

88.0%

86.0%

84.0%

82.0%

80.0%

78.0%

76.0%

74.0%

72.0%

70.0%

90.0%

88.0%

86.0%

84.0%

82.0%

80.0%

78.0%

76.0%

74.0%

72.0%

70.0%

3s3p

4s3p

5s3p

6s3p

3s3p

4s3p

5s3p

6s3p

ILED (mA)

C004

C003

Figure 11. LED Efficiency vs I_LED

Figure 12. LED Efficiency vs I_LED

1.70

1.50

1.30

1.10

0.90

0.70

0.50

1.01

1.00

0.99

0.98

0.97

0.96

0.95

0.94

0.93

0.92

0.91

0.90

-40°C

85°C

25°C

85°C

-40°C

25°C

VIN (V)

C001

Figure 13. Shutdown Current vs V_IN

Figure 14. Open Loop Current Limit vs V_IN

LM3699

ZHCSCB2A –JANUARY 2014–REVISED MARCH 2014

www.ti.com.cn

V_IN= 3.6 V, LEDs are WLEDs part # SML-312WBCW(A), Typical Application Circuit with L = TDK (VLF302512, 10 µH, 22 µH

where specified), Schottky = On-Semi (NSR0240V2T1G), T_A= 25°C unless otherwise specified. Efficiency is given as (V_OUT

(I_HVLED1+ I_HVLED2+ I_HVLED3))/(V_IN× I_IN), matching curves are given as (ΔI_{LED_MAX}/I_{LED_AVE}).

100.00%

10.00%

1.00%

0.10%

0.01%

D_PWM= 100%

3 x 6 LEDs

20 mA/String

PWM FREQUENCY (Hz)

C001

D_PWM= 50%

3 x 6 LEDs

20 mA/String

Figure 16. Start-Up Response

Figure 15. LED Current Ripple vs F_PWM

D_PWM= 0%

3 x 6 LEDs

20 mA/String

3p6s

D_PWM= 30% to 90%

ƒ = 10 kHz

20.2 mA/String

Figure 17. Start-Up Response

Figure 18. D_PWMStep Change Response

3p6s

20.2 mA/String

D_PWM= 100%

3p6s

20.2 mA/String

D_PWM= 100%

4.2 V to 3.6 V

Figure 20. V_INStep Response

Figure 19. V_INStep Response

LM3699

www.ti.com.cn

ZHCSCB2A –JANUARY 2014–REVISED MARCH 2014

V_IN= 3.6 V, LEDs are WLEDs part # SML-312WBCW(A), Typical Application Circuit with L = TDK (VLF302512, 10 µH, 22 µH

where specified), Schottky = On-Semi (NSR0240V2T1G), T_A= 25°C unless otherwise specified. Efficiency is given as (V_OUT

(I_HVLED1+ I_HVLED2+ I_HVLED3))/(V_IN× I_IN), matching curves are given as (ΔI_{LED_MAX}/I_{LED_AVE}).

3p6s

20.2 mA/String

D_PWM= 50%

3p6s

20.2 mA/String

D_PWM= 100%

3.6 V to 4.2 V

Figure 22. ILOW Disabled

Figure 21. V_INStep Response

3p6s

20.2 mA/String

D_PWM= 50%

Figure 23. ILOW Enabled

9 Power Supply Recommendations

The LM3699 is designed to operate from an input voltage supply range of 2.7 V to 5.5 V. The input supply

connection must be properly designed to support the LM3699 maximum peak current limit.

LM3699

ZHCSCB2A –JANUARY 2014–REVISED MARCH 2014

www.ti.com.cn

10 Layout

10.1 Layout Guidelines

The LM3699 inductive boost converter sees a high switched voltage (up to 24 V) at the SW terminal, as well as a

step current (up to 1 A) through the Schottky diode and output capacitor each switching cycle. The high switching

voltage can create interference into nearby nodes due to electric field coupling (I = CdV/dt). The large step

current through the diode and the output capacitor can cause a large voltage spike at the SW and OVP terminals

due to parasitic inductance in the step current conducting path (V = Ldi/dt). Board layout guidelines are geared

towards minimizing this electric field coupling and conducted noise. Figure 24 highlights these two noise-

generating components.

Voltage Spike

V_OUT+ V_FSchottky

Pulsed voltage at SW

I_PEAK

Current through

Schottky and

COUT

I_AVE= I_IN

Current through

Inductor

Parasitic

Circuit Board

Inductances

Affected Node

due to Capacitive Coupling

LCD Display

Cp1

Lp1

Lp2

Up to 24V

2.7 V to 5.5 V

C_OUT

Lp3

C_IN

LM3699

PWM

OVP

HWEN

ILOW

IS1

IS0

HVLED1

HVLED2

HVLED3

GND

Figure 24. LM3699 Inductive Boost Converter Showing Pulsed Voltage At SW (High dv/dt) And Current

Through Schottky And C_OUT(High di/dt)

The following list details the main (layout sensitive) areas of the LM3699 inductive boost converter in order of

decreasing importance:

1. Output Capacitor

–

Schottky Cathode to C_OUT+

COUT− to GND

2. Schottky Diode

–

SW Terminal to Schottky Anode

Schottky Cathode to C_OUT

LM3699

www.ti.com.cn

ZHCSCB2A –JANUARY 2014–REVISED MARCH 2014

Layout Guidelines (continued)

3. Inductor

–

SW Node PCB capacitance to other traces

4. Input Capacitor

–

CIN+ to IN terminal

10.1.1 Boost Output Capacitor Placement

Because the output capacitor is in the path of the inductor current discharge path, a high-current step from 0 to

I_PEAKoccurs each time the switch turns off and the Schottky diode turns on. Any inductance along this series

path from the cathode of the diode through C_OUTand back into the LM3699 GND terminal contributes to voltage

spikes (V_SPIKE= LP_ × di/dt) at SW and OUT. These spikes can potentially over-voltage the SW terminal, or feed

through to GND. To avoid this, C_OUT+ must be connected as close as possible to the Cathode of the Schottky

diode, and C_OUT− must be connected as close as possible to the LM3699 GND terminal. The best placement for

C_OUTis on the same layer as the LM3699 so as to avoid any vias that can add excessive series inductance.

10.1.2 Schottky Diode Placement

In the boost circuit of the device the Schottky diode is in the path of the inductor current discharge. As a result

the Schottky diode sees a high-current step from 0 to I_PEAKeach time the switch turns off and the diode turns on.

Any inductance in series with the diode may cause a voltage spike (V_SPIKE= LP_ × di/dt) at SW and OUT. This

can potentially over-voltage the SW terminal, or feed through to V_OUTand through the output capacitor and into

GND. Connecting the anode of the diode as close as possible to the SW terminal and the cathode of the diode

as close as possible to C_OUT+ reduces the inductance (LP_) and minimize these voltage spikes.

10.1.3 Inductor Placement

The node where the inductor connects to the LM3699 SW terminal has 2 issues. First, a large switched voltage

(0 to V_OUT+ VF_SCHOTTKY) appears on this node every switching cycle. This switched voltage can be

capacitively coupled into nearby nodes. Second, there is a relatively large current (input current) on the traces

connecting the input supply to the inductor and connecting the inductor to the SW terminal. Any resistance in this

path can cause voltage drops that can negatively affect efficiency and reduce the input operating voltage range.

To reduce the capacitive coupling of the signal on SW into nearby traces, the SW terminal-to-inductor connection

must be minimized in area. This limits the PCB capacitance from SW to other traces. Additionally, high-

impedance nodes that are more susceptible to electric field coupling need to be routed away from SW and not

directly adjacent or beneath. This is especially true for traces such as IS1, IS0, ILOW, HWEN, and PWM. A GND

plane placed directly below SW greatly reduce the capacitance from SW into nearby traces.

Lastly, limit the trace resistance of the VBATT-to-inductor connection and from the inductor-to-SW connection, by

use of short, wide traces.

10.1.4 Boost Input Capacitor Placement

For the LM3699 boost converter, the input capacitor filters the inductor current ripple and the internal MOSFET

driver currents during turnon of the internal power switch. The driver current requirement can range from 50 mA

at 2.7 V to over 200 mA at 5.5 V with fast durations of approximately 10 ns to 20 ns. This appears as high di/dt

current pulses coming from the input capacitor each time the switch turns on. Close placement of the input

capacitor to the IN terminal and to the GND terminal is critical since any series inductance between IN and C_IN+

or C_IN− and GND can create voltage spikes that could appear on the V_INsupply line and in the GND plane.

LM3699

ZHCSCB2A –JANUARY 2014–REVISED MARCH 2014

www.ti.com.cn

10.2 Layout Example

Figure 25 requires two PCB layers and is optimized for the GND connection.

Figure 25. LM3699 GND Optimized Layout Example

LM3699

www.ti.com.cn

ZHCSCB2A –JANUARY 2014–REVISED MARCH 2014

11 器件和文档支持

11.1 器件支持

11.1.1 Third-Party Products Disclaimer

TI'S PUBLICATION OF INFORMATION REGARDING THIRD-PARTY PRODUCTS OR SERVICES DOES NOT

CONSTITUTE AN ENDORSEMENT REGARDING THE SUITABILITY OF SUCH PRODUCTS OR SERVICES

OR A WARRANTY, REPRESENTATION OR ENDORSEMENT OF SUCH PRODUCTS OR SERVICES, EITHER

ALONE OR IN COMBINATION WITH ANY TI PRODUCT OR SERVICE.

11.2 Trademarks

All trademarks are the property of their respective owners.

11.3 Electrostatic Discharge Caution

This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with

appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.

ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more

susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.

11.4 Glossary

SLYZ022 — TI Glossary.

This glossary lists and explains terms, acronyms and definitions.

12 机械封装和可订购信息

以下页中包括机械封装和可订购信息。这些信息是针对指定器件可提供的最新数据。这些数据会在无通知且不对

本文档进行修订的情况下发生改变。要获得这份数据表的浏览器版本，请查阅左侧导航栏。

PACKAGE OPTION ADDENDUM

www.ti.com

10-Dec-2020

PACKAGING INFORMATION

Orderable Device

Status Package Type Package Pins Package

Eco Plan

Lead finish/

Ball material

MSL Peak Temp

Op Temp (°C)

Device Marking

Samples

Drawing

Qty

(1)

(2)

(3)

(4/5)

(6)

LM3699YFQR

ACTIVE

DSBGA

YFQ

3000 RoHS & Green

SNAGCU

Level-1-260C-UNLIM

-40 to 125

⁽¹⁾The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs.

LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.

NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available.

OBSOLETE: TI has discontinued the production of the device.

⁽²⁾RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance

do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may

reference these types of products as "Pb-Free".

RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.

Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of <=1000ppm threshold. Antimony trioxide based

flame retardants must also meet the <=1000ppm threshold requirement.

⁽³⁾MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.

⁽⁴⁾There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.

⁽⁵⁾Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation

of the previous line and the two combined represent the entire Device Marking for that device.

(6)

Lead finish/Ball material - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead finish/Ball material values may wrap to two

lines if the finish value exceeds the maximum column width.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information

provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and

continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.

TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

Addendum-Page 1

PACKAGE MATERIALS INFORMATION

www.ti.com

9-Aug-2022

TAPE AND REEL INFORMATION

REEL DIMENSIONS

TAPE DIMENSIONS

Reel

Diameter

Cavity

A0 Dimension designed to accommodate the component width

B0 Dimension designed to accommodate the component length

K0 Dimension designed to accommodate the component thickness

Overall width of the carrier tape

P1 Pitch between successive cavity centers

Reel Width (W1)

QUADRANT ASSIGNMENTS FOR PIN 1 ORIENTATION IN TAPE

Sprocket Holes

Q1 Q2

Q3 Q4

Q1 Q2

Q3 Q4

User Direction of Feed

Pocket Quadrants

*All dimensions are nominal

Device

Package Package Pins

Type Drawing

SPQ

Reel

Pin1

Diameter Width (mm) (mm) (mm) (mm) (mm) Quadrant

(mm) W1 (mm)

LM3699YFQR

DSBGA

YFQ

3000

178.0

8.4

1.35

1.75

0.76

4.0

8.0

Pack Materials-Page 1

PACKAGE MATERIALS INFORMATION

www.ti.com

9-Aug-2022

TAPE AND REEL BOX DIMENSIONS

Width (mm)

*All dimensions are nominal

Device

Package Type Package Drawing Pins

DSBGA YFQ 12

SPQ

Length (mm) Width (mm) Height (mm)

208.0 191.0 35.0

LM3699YFQR

3000

Pack Materials-Page 2

MECHANICAL DATA

YFQ0012xxx

0.600

±0.075

TMD12XXX (Rev B)

D: Max = 1.64 mm, Min = 1.58 mm

E: Max = 1.29 mm, Min = 1.23 mm

4215079/A

12/12

A. All linear dimensions are in millimeters. Dimensioning and tolerancing per ASME Y14.5M-1994.

B. This drawing is subject to change without notice.

NOTES:

www.ti.com

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LM3699 [TI]

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