TPS62770 [TI]

采用 WCSP 封装且具有 360nA Iq 降压和高达 15V 升压功能的微型单芯片双重解决方案;


型号：	TPS62770
厂家：	TEXAS INSTRUMENTS
描述：	采用 WCSP 封装且具有 360nA Iq 降压和高达 15V 升压功能的微型单芯片双重解决方案
文件：	总37页 (文件大小：2740K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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TPS62770

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

TPS62770 面向可穿戴应用的多轨 DC/DC 转换器

1 特性

3 说明

•

VIN 范围为 2.5V 至 5.5V

370nA Iq 降压转换器

TPS62770 是一套面向可穿戴应用的超小型电源解决

方案，其包括一个 370nA 超低 Iq 降压转换器、一个受

转换率控制的负载开关以及一个双模式降压转换器。该

降压转换器的输出电压可通过三个 VSEL 引脚在

1.0V、1.05V、1.1V、1.2V、1.8V、1.9V、2.0V 和

3.0V 之间选择。可以在运行期间更改输出电压。在关

断模式下，该降压转换器的输出拉至 GND。集成的负

载开关从内部连接至降压转换器的输出，并且接通阶

段可控制转换率。关闭后，其输出连接到 GND。

–

8 个可选输出电压（1.0V 至 3.0V）

300mA 输出电流

输出放电功能

•

受转换率控制的负载开关，具有放电功能

双模式降压转换器

–

负载断开

恒定输出电压，最高可调节至 15V (V_FB0.8 V)

/12V（固定值）

双模式降压转换器既可以生成最高达 15V 的恒定输出

电压（例如 PMOLED 电源），也可以提供恒定输出电

流（例如 LED 背光电源）。输出电压可通过外部电阻

最高调节至 15V，也可以通过将 FB 引脚连接至 VIN

设为 12V 固定电压。该器件具有 17.7V 内部过压保

护，用于 FB 节点悬空或接地情况。该器件包含内部整

流器和负载断开功能。用作恒定输出电流驱动器时，该

器件可为模拟转换器提供 PWM，以便其根据 PWM 信

号的占空比按比例减小基准电压。

–

发光二极管 (LED) 电流驱动器，提供脉宽调制

(PWM) 用于电流转换（D = 100% 时的最大

V_FB电压为 200mV）

•

超小型 16 引脚 1.58mm x 1.58mm WCSP 封

装，0.4mm 间距

2 应用

•

可穿戴和个人电子产品

健身配件

健康状况监控和医疗配件

该器件采用小型 16 引脚 0.4mm 间距的 WCSP 封装。

器件信息⁽¹⁾

器件型号

TPS62770

封装

封装尺寸（标称值）

DSBGA (16)

1.58mm x 1.58mm

(1) 要了解所有可用封装，请见数据表末尾的可订购产品附录。

典型应用电路原理图

TPS62770

VOUT1 = 1.8V/300mA

MCU / BLE

L1 = 2.2mH

VIN

SW1

VO1

DC/DC 1

Step Down Converter

EN1

C_IN

10mF

C_OUT1

VSEL3

VSEL2

VSEL1

10mF

Load Output = 1.8V

Sensors

LOAD

VO2

ON/OFF

CTRL

Load Switch

L2 = 10mH

VOUT2 = 12V / 30mA

PMOLED

SW2

EN2/PWM

DC/DC 2

Step up converter

C_OUT2

10mF

GND1

GND2

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.

English Data Sheet: SLVSCX0

TPS62770

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

www.ti.com.cn

7.4 Device Functional Modes........................................ 13

Application and Implementation ........................ 17

8.1 Application Information............................................ 17

8.2 Typical Application ................................................. 18

Power Supply Recommendations...................... 31

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

应用.......................................................................... 1

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

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

Pin Configuration and Functions......................... 3

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

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

6.2 ESD Ratings ............................................................ 4

6.3 Recommended Operating Conditions....................... 5

6.4 Thermal Information ................................................. 5

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

6.6 Typical Characteristics.............................................. 8

Detailed Description .............................................. 9

7.1 Overview ................................................................... 9

7.2 Functional Block Diagram ......................................... 9

7.3 Feature Description................................................. 10

10 Layout................................................................... 31

10.1 Layout Guidelines ................................................. 31

10.2 Layout Example .................................................... 31

11 器件和文档支持 ..................................................... 33

11.1 器件支持 ............................................................... 33

11.2 文档支持 ............................................................... 33

11.3 商标....................................................................... 33

11.4 静电放电警告......................................................... 33

11.5 Glossary................................................................ 33

12 机械、封装和可订购信息....................................... 33

4 修订历史记录

Changes from Original (February 2016) to Revision A

Page

•

已更改器件状态至“量产数据”且已发布完整数据表。 ............................................................................................................. 1

TPS62770

www.ti.com.cn

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

5 Pin Configuration and Functions

YFP Package

16-Pin DSBGA

Top View

GND2

SW2

VO2

VSEL3

EN2/

PWM

SW1

VIN

VSEL2

EN1

VSEL1

CTRL

LOAD

GND1

VO1

Pin Functions

I/O

DESCRIPTION

NAME

EN2/PWM

Enable pin for the step-up converter. High level enables the devices, low level turns the device into

shutdown mode. A PWM signal can be applied to this pin when used as a constant current driver (BM pin

connected to VIN). The pin must be terminated.

GND2

SW2

PWR GND supply pin for the step-up converter. Connect this pin close to the GND terminals of the input and

output capacitors.

The switch pin of the step-up converter. It is connected to the drain of the internal power MOSFET.

Connect the inductor L2 between this pin and the input capacitor CIN

VO2

OUT

Output of the step-up converter.

This pin controls the operation mode of the step-up converter. With BM = high, the device features a low

feedback voltage of 200mV, which can be scaled down by the integrated PWM to analog converter. With

BM = low, the device operates with a 0.8V feedback voltage and operates as a step-up converter with

voltage regulation. This pin must be terminated and set before the device is enabled.

Feedback pin for the step-up converter to set the output voltage / current. Connect the pin to the center tap

of a resistor divider to program the output voltage. When it is connected to the VIN pin, the output voltage

is set to 12 V by an internal feedback divider network. When used as a LED current driver connect the

sense resistor between this pin and GND. The LED string is connected between FB pin and VO2.

EN1

Enable pin for the step-down converter. High level enables the devices, low level turns the device into

shutdown mode. The pin must be terminated.

VSEL1

VSEL2

VSEL3

CTRL

Output voltage selection pins. See Table 1 for V_OUTselection. These pins must be terminated. The pins

can be dynamically changed during operation.

This pin controls the load switch between VO1 and LOAD. With CTRL = low, the LOAD switch is disabled.

The pin must be terminated.

VIN

PWR VIN power supply pin. Connect the input capacitor close to this pin for best noise and voltage spike

suppression. A ceramic capacitor of 10μF is required.

GND1

SW1

VO1

PWR GND supply pin for the step-down converter. Connect this pin close to both, the GND terminal of the input

and output capacitor.

OUT

This is the switch pin of the step-down converter and is connected to the internal MOSFET switches.

Connect the inductor L1 between this terminal and the output capacitor.

OUT

Output of the step-down converter. The output voltage is sensed via this pin to the internal feedback divider

network for the regulation loop. In addition the internal load switch is connected between VO1 pin and

LOAD pin. Connect this pin directly to the output capacitor with a short trace. The pin is connected to

GND1 and discharges the output capacitor when the converter is disabled.

LOAD

OUT

Output terminal of the internal load switch. With CTRL = high, the internal load switch connects VO1 to the

LOAD pin. The switch features a slew rate control. This pin is pulled to GND with the CTRL = low. If not

used, leave the pin open.

TPS62770

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

www.ti.com.cn

Table 1. Output Voltage Setting Step-Down Converter

VO1 [V]

1.0

VSEL3

VSEL2

VSEL1

1.05

1.1

1.2

1.8

1.9

2.0

3.0

6 Specifications

6.1 Absolute Maximum Ratings

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

(1)

MIN

–0.3

-0.3

–0.3

–40

MAX

UNIT

VIN, FB

SW1

V_IN+0.3V

Pin voltage⁽²⁾

EN1, EN2/PWM, CTRL, BM, VSEL1-3

SW2, VO2

VO1, LOAD

3.7

T_J

Operating junction temperature range

Storage temperature range

125

°C

T_stg

–65

150

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

only and functional operation of the device at these or any other conditions beyond those indicated under recommended operating

conditions is not implied. Exposure to absolute–maximum–rated conditions for extended periods may affect device reliability.

(2) All voltage values are with respect to network ground terminal GND.

6.2 ESD Ratings

VALUE

UNIT

Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all

pins⁽¹⁾

± 2000

V_(ESD)

Electrostatic discharge

Charged device model (CDM), per JEDEC specification

JESD22-C101, all pins⁽²⁾

±500

(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. The human body

model is a 100-pF capacitor discharged through a 1.5-kΩ resistor into each pin.

(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

TPS62770

www.ti.com.cn

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

6.3 Recommended Operating Conditions

MIN NOM MAX UNIT

V_IN

Input voltage range at VIN pin

DC/DC 1 Step down

converter output current

2.5

5.5

I_OUT1

L1 = 2.2µH, C_OUT1= 10 µF

300 mA

2.5V < VIN < 5.5V, VOUT2 = 12V, C_OUT2= 10uF, L = 10µH

2.5V < VIN < 5.5V, VOUT2 = 12V, C_OUT2= 2x 10uF, L = 10µH

3V < VIN < 5.5V, VOUT2 = 5V, C_OUT2= 2x 10uF, L = 4.7µH

DC/DC 2 Step up

converter output current

I_OUT2

100

°C

200

Load current (current

from LOAD pin)

I_LOAD

100

T_J

Operating junction temperature range

Ambient temperature range

-40

125

T_A

6.4 Thermal Information

TPS62770

YFP

THERMAL METRIC⁽¹⁾

UNIT

TERMINALS

90.6

R_θJA

Junction-to-ambient thermal resistance

Junction-to-case (top) thermal resistance

R_θJCtop

R_θJB

0.6

Junction-to-board thermal resistance

13.8

°C/W

ψ_JT

Junction-to-top characterization parameter

Junction-to-board characterization parameter

Junction-to-case (bottom) thermal resistance

2.8

ψ_JB

13.7

R_θJCbot

n/a

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

report, SPRA953.

6.5 Electrical Characteristics

V_IN= 3.6V, T_A= –40°C to 85°C typical values are at T_A= 25°C (unless otherwise noted)

PARAMETER

TEST CONDITIONS

MIN

TYP MAX

UNIT

SUPPLY

Shutdown current

into V_IN

I_SD

EN1 = EN2/PWM = GND, CTRL GND, BM = GND,

0.1 1850

V_{TH_ UVLO+}

V_{TH_UVLO-}

Rising V_IN

Falling V_IN

2.1

1.9

2.22

Undervoltage

lockout threshold

INPUTS EN1, EN2/PWM, BM, CTRL,VSEL 1-3

High level input

threshold

V_{IH TH}

1.2

Low level input

threshold

V_{IL TH}

0.4

T_J= 25°C

I_IN

Input bias Current

T_J= –40°C to 85°C

TPS62770

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

www.ti.com.cn

Electrical Characteristics (continued)

V_IN= 3.6V, T_A= –40°C to 85°C typical values are at T_A= 25°C (unless otherwise noted)

PARAMETER

TEST CONDITIONS

MIN

TYP MAX

UNIT

STEP-DOWN CONVERTER

EN1 = V_IN, EN2/PWM = GND, CTRL = GND, I_OUT= 0µA, V_OUT= 1.8V,

device not switching,

370 1850

500

Operating

quiescent current

I_Q

EN1 = V_IN, EN2/PWM = GND, I_OUT= 0mA, CTRL = GND, V_OUT

1.8V , device switching

Output voltage

range

1.0

3.0

PFM mode

PWM mode

-2.5

-2

2.5

Output voltage

accuracy

V_VOUT

DC output voltage

load regulation

V_OUT= 1.8V

0.001

%/mA

%/V

DC output voltage

line regulation

V_OUT= 1.8V, I_OUT= 10 mA, 2.5V ≤ V_IN≤ 5.5V

High side

MOSFET on-

resistance

0.45

0.22

R_DS(ON)

I_OUT= 50mA

Ω

Low Side

MOSFET on-

resistance

High side

MOSFET switch

current limit

480

600

720

I_LIMF

Low side MOSFET

switch current limit

Discharge switch

on-resistance

R_{DSCH_VO1}

EN = GND, I_VO1= -10mA into VO1 pin

Ω

T_J= 25°C

100

Bias current into

VO1 pin

I_{IN_VO1}

EN = V_IN, V_OUT= 1.8V

T_J= –40°C to 85°C

1010

Auto 100% Mode

leave detection

threshold

Rising V_IN,100% Mode is left with V_IN= V_OUT+ V_{TH_100+}, max value at

T_J= 85°C

V_{TH_100+}

150

250

200

370

310

(1)

Auto 100% Mode

enter detection

Falling V_IN, 100% Mode is entered with V_IN= V_OUT+ V_{TH_100-}, max

value at T_J= 85°C

V_{TH_100-}

(1)

threshold

t_ONmin

Minimum ON time V_OUT= 2.0V, I_OUT= 0 mA

Minimum OFF time

225

t_OFFmin

Regulator start up

delay time

t_{Startup_delay}

From transition EN1 = low to high until device starts switching

µs

Softstart time with

reduced switch

current limit

t_Softstart

700 1200

High side

MOSFET switch

current limit

150

200

I_{LIM_softstart}

Reduced switch current limit during softstart

I_LOAD= 50mA, CTRL = V_IN, V_OUT= 1.8V,

Low side MOSFET

switch current limit

LOAD SWITCH

MOSFET on-

resistance

R_LOAD

0.6

1.27

800

Ω

μs

Starting with CTRL low to high transition, time to ramp V_LOADfrom

95%, V_OUT= 1.8V, I_LOAD= 20mA

t_{rise_LOAD}

R_DCHRG

V_LOADrise time

315

MOSFET on-

resistance

(1) V_INis compared to the programmed output voltage (V_OUT). When V_IN–V_OUTfalls below V_{TH_100-}the device enters 100% Mode by turning

the high side MOSFET on. The 100% Mode is exited when V_IN–V_OUTexceeds V_{TH_100+}and the device starts switching. The hysteresis

for the 100% Mode detection threshold V_{TH_100+}- V_{TH_100-}will always be positive and will be approximately 50 mV(typ.)

TPS62770

www.ti.com.cn

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

Electrical Characteristics (continued)

V_IN= 3.6V, T_A= –40°C to 85°C typical values are at T_A= 25°C (unless otherwise noted)

PARAMETER

STEP-UP CONVERTER

I_{Q_VIN}

TEST CONDITIONS

MIN

TYP MAX

UNIT

Quiescent current

into VIN pin

EN2/PWM = VIN, BM = GND, EN1 = GND, no load, no switching, V_OUT

= 12 V

110

200

µA

V_OUT

V_{OUT_12V}

V_FB

Output voltage

range

EN2/PWM = VIN, BM = GND

4.5

11.7

12-V output

voltage accuracy

FB pin connected to VIN pin, EN2/PWM = V_IN, BM = GND

12.3

Feedback voltage

PWM mode, BM = GND, EN2/PWM = V_IN

PFM mode, BM = GND, EN2/PWM = V_IN

EN2/PWM = VIN, BM = VIN,

0.775

0.795 0.814

0.803

Feedback

189

200

206

regulation voltage

under brightness

control

VFB =50mV, BM = VIN, D(PWM) @ EN2/PWM = 25%,

VFB = 20mV, BM = VIN, D(PWM) @ EN2/PWM = 10%

t_{Dim_Off}

t_{Dim_On}

V_OVP

Dimming signal on

pin EN2/PWM

270

160

μs

Output overvoltage

protection

threshold

17.7

800

18.4

V_{OVP_HYS}

Over voltage

protection

hysteresis

I_{FB_LKG}

I_{SW_LKG}

R_DS(on)

Leakage current

into FB pin

200

500

Leakage current

into SW pin

EN2/PWM = GND

Isolation MOSFET V_OUT= 12 V

on resistance

850

450

mΩ

Low-side MOSFET V_OUT= 12 V

on resistance

f_SW

Switching

frequency

V_OUT= 12 V, PWM mode

850

730

1050 1250

150 250

970 1230

kHz

t_{ON_min}

I_{LIM_SW}

Minimal switch on

time

Peak switch

current limit

V_OUT= 12 V

I_{LIM_CHG}

t_Softstart

Pre-charge current V_OUT= 0 V

Pre-charge time

BM = GND, EN2/PWM from low to high until device starts switching,

I_OUT2= 0mA, C_OUT2= 10uF

Startup time

V_OUTfrom V_INto 12 V, C_{OUT_effective}= 2.2 µF, I_OUT= 0 A

TPS62770

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

www.ti.com.cn

6.6 Typical Characteristics

1000

160

140

120

100

TA = -40°C

TA = 0°C

TA = -20°C

TA = 25°C

TA = 85°C

900

800

700

600

500

400

300

200

100

TA = 60°C

TA = -40°C

TA = 0°C

TA = -20°C

TA = 25°C

TA = 85°C

TA = 60°C

2.5

3.5

4.5

5.5

VIN [V]

EN2/PWM = low

EN1 = high

VOUT1 set to 1.8V

EN2/PWM = high

EN1 = low

VOUT2 set to 12V

device not

switching

device not

switching

图 1. Quiescent current I_QStep-Down converter

图 2. Quiescent current I_QStep-Up converter

500

TA = -40°C

450

TA = -20°C

TA = 25°C

TA = 85°C

TA = 0°C

400

350

300

250

200

150

100

TA = 60°C

2.5

3.5

VIN [V]

4.5

5.5

EN1 = EN2/PWM = low

图 3. Shutdown current I_SDN

TPS62770

www.ti.com.cn

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

7 Detailed Description

7.1 Overview

The TPS62770 is a tiny power solution for wearable applications including a 370nA ultra low Iq step-down

converter, a slew rate controlled load switch and a dual mode step-up converter. The output voltage of the step-

down converter can be selected with three VSEL pins between 1.0 V, 1.05 V, 1.1 V, 1.2 V, 1.8 V, 1.9 V, 2.0 V

and 3.0 V.

The dual mode step-up converter can generate a constant output voltage up to 15 V, such as PMOLED supply

or, a constant output current, such as LED back light supply.

7.2 Functional Block Diagram

TPS62770

VIN

SW1

DC/DC 1

Step Down

Converter

EN1

VO1

VSEL1

VSEL2

VSEL3

CTRL

LOAD

VO2

Load Switch

SW2

DC/DC 2

Step up converter

EN2/PWM

GND2

GND1

TPS62770

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

www.ti.com.cn

7.3 Feature Description

7.3.1 Step-Down Converter Device

CTRL

VO1

UVLO

Ultra Low Power

Reference V_REF= 1.2V

Softstart

EN1

V_OUT

Discharge

VSEL1

VSEL2

VSEL3

VOUT

Load Switch

UVLO

Comp

Auto 100% Mode

Slew Rate

Control

Comp

100%

Mode

Internal

V_FBfeedback

CTRL

VIN

LOAD

UVLO

divider

network*

Discharge

V_{TH_100}

V_{TH_UVLO}

UVLO

Power Stage

PMOS

Current

Limit Comparator

VIN

Timer

Min. On

UVLO

DCS

Control

VIN

Limit

High Side

VOUT

Min. OFF

VOUT

Control

Logic

Direct Control

& Compensation

Gate Driver

Anti

SW1

Shoot-Through

V_FB

V_REF

NMOS

Limit

Low Side

Error

amplifier

Main

Comparator

GND1

Current

Limit Comparator

* typical 50MW

图 4. Block diagram Step-Down Converter with Load Switch

7.3.1.1 DCS-Control™

TI's DCS-Control™ (Direct Control with Seamless Transition into Power Save Mode) is an advanced regulation

topology, which combines the advantages of hysteretic and voltage mode control. Characteristics of DCS-Control

™ are excellent AC load regulation and transient response, low output ripple voltage and a seamless transition

between PFM and PWM mode operation. DCS-Control™ includes an AC loop which senses the output voltage

(VO1 pin) and directly feeds the information to a fast comparator stage. This comparator sets the switching

frequency, which is constant for steady state operating conditions, and provides immediate response to dynamic

load changes. In order to achieve accurate DC load regulation, a voltage feedback loop is used. The internally

compensated regulation network achieves fast and stable operation with small external components and low

ESR capacitors. The DCS-Control™ topology supports PWM (Pulse Width Modulation) mode for medium and

high load conditions and a Power Save Mode at light loads. Since DCS-Control™ supports both operation modes

within one single building block, the transition from PWM to Power Save Mode is seamless with minimum output

voltage ripple. The step-down converter offers both excellent DC voltage and superior load transient regulation,

combined with low output voltage ripple, minimizing interference with RF circuits.

7.3.1.2 Output Voltage Selection with pins VSEL1-VSEL3

The step-down converter doesn't require an external resistor divider network to program the output voltage. The

device integrates a high impedance feedback resistor divider network that is programmed by the pins VSEL1-3. It

supports an output voltage range from 1.0 V to 3.0 V. The output voltage is programmed according to Table 1 .

The output voltage can be changed during operation. This can be used for simple dynamic output voltage

scaling.

TPS62770

www.ti.com.cn

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

Feature Description (接下页)

7.3.1.3 CTRL / Output Load

With the CTRL pin set to high, the integrated loadswitch is activated and connects the LOAD pin to the VO1 pin

to power up an additional sub-system. The load switch is slew rate controlled to support soft switching and not to

impact the regulated output VO1. If CTRL pin is pulled to GND, the LOAD pin is disconnected from the VO1 pin

and internally connected to GND by an internal discharge switch. The CTRL pin can be controlled by a micro

controller.

7.3.1.4 Output Discharge At Pins VO1 And LOAD

Both the VO1 pin and the LOAD pin feature a discharge circuit to connect each rail to GND, once they are

disabled. This feature prevents residual charge voltages on capacitors connected to these pins, which may

impact proper power up of the main- and sub-system. With CTRL pin pulled to low, the discharge circuit at the

LOAD pin becomes active. With the EN pin pulled to low, the discharge circuits at both pins VO1 and Load are

active. The discharge circuits of both rails VO1 and LOAD are associated with the UVLO comparator as well.

Both discharge circuits become active once the input voltage VIN has dropped below the UVLO comparator

threshold VTH_UVLO- and the UVLO comparator triggers.

7.3.1.5 Undervoltage Lockout UVLO

The UVLO circuit shuts down the device if the input voltage V_INdrops to typical 1.9V. The device will start up at

an input voltage of typ. 2.1V.

7.3.1.6 Short Circuit Protection

The step-down converter integrates a current limit on the high side, as well on the low side MOSFETs to

protect the device against overload or short circuit conditions. The peak current in the switches is monitored

cycle by cycle. If the high side MOSFET current limit is reached, the high side MOSFET is turned off and the

low side MOSFET is turned on until the switch current decreases below the low side MOSFET current limit.

Once the low side MOSFET current limit trips, the low side MOSFET is turned off and the high side MOSFET

turns on again.

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Feature Description (接下页)

7.3.2 Step-Up Converter Device

SW2

VIN

VO2

Isolation

MOSFET

Rectifier

VO2

Gate Driver

NMOS

Switch

Pre-charge,

Short Circuit Protection

Load Disconnect

OVP

Softstart&

Current Limit

Control

Fixed VOUT

Detector

PFM/PWM

Control

Reference System

V_REF

BM = low

V_REF= 795mV

Mode

Selection

Error

Amplifier

PWM to

V_REFConverter

V_REF= D_PWM* 200mV

EN2/PWM

BM = high

GND2

图 5. Block Diagram Step-Up Converter

The step-up converter is designed for applications requiring voltages up to 15V from an Li-Ion battery and tiny

solution size such as PMOLED displays or LED back light for small size LCD displays. The step-up converter

operates in two different modes, either as constant output voltage step-up converter operating with 0.8V internal

reference or as a constant output current step-up converter operating with a reduced internal reference voltage of

200mV. The block integrates power switch, input/output isolation switch, and power diode.

7.3.2.1 Under-Voltage Lockout

See section Undervoltage Lockout UVLO

7.3.2.2 Output Disconnect

One common issue with conventional step-up regulators is the conduction path from input to output even when

the device is disabled. It creates three problems, which are inrush current during start-up, output leakage current

during shutdown and excessive over load current. The step-up converter has an integrated isolation (load

disconnect) switch, which is turned off under shutdown mode and over load conditions, thereby opening the

current path to the output VO2. Thus the device can truly disconnect the load from the input voltage and

minimize the leakage current during shutdown mode.

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Feature Description (接下页)

7.3.2.3 12V Fixed Output Voltage

The step-up converter features an internal default 12-V output voltage setting by connecting the FB pin to the

VIN pin. Therefore no external resistor divider network is required minimizing the total solution size.

7.3.2.4 Mode Selection With Pin BM

The step-up converter can operate in two different modes. With pin BM = low the device regulates to a constant

output voltage, with BM = high, the device can regulate a constant output current. Further details in section

Constant-Current Step-Up Mode Operation and section Constant-Voltage Step-Up Mode Operation. The

operation mode need to be selected before the device is enabled. The pin BM may not be changed during

operation.

7.3.2.5 Output Overvoltage Protection

When the output voltage exceeds the OVP threshold of 17.7 V, the device stops switching. Once the output

voltage falls 0.8 V below the OVP threshold, the device resumes operation again.

7.3.2.6 Output Short Circuit Protection

The step-up converter starts to limit the output current whenever the output voltage drops below 4 V. When the

VOUT pin is shorted to ground, the output current is limited. This function protects the device from being

damaged when the output is shorted to ground.

7.3.2.7 PWM to Analog Converter AT PIN EN2/PWM

In constant current step-up mode operation two control functions are associated with the pin EN2/PWM:

a) Enable/ disable of the step-up converter

b) PWM to analog conversion to scale the internal reference voltage.

The internal reference voltage scales proportional with the duty cycle of the PWM signal applied at the pin

EN2/PWM. More details in section Constant-Current Step-Up Mode Operation.

7.4 Device Functional Modes

7.4.1 Step-Down Converter

7.4.1.1 Enable and Shutdown

The step-down converter is turned on with EN1 = high. With EN1 = low the step-down converter is turned off.

This pin must be terminated.

7.4.1.2 Power Save Mode Operation

At light loads, the device operates in Power Save Mode. The switching frequency varies linearly with the load

current. In Power Save Mode the device operates in PFM (Pulse Frequency Modulation) that generates a single

switching pulse to ramp up the inductor current and recharges the output capacitor, followed by a sleep period

where most of the internal circuits are shutdown to achieve lowest operating quiescent current. During this time,

the load current is supported by the output capacitor. The duration of the sleep period depends on the load

current and the inductor peak current. During the sleep periods, the current consumption is reduced to 360 nA.

This low quiescent current consumption is achieved by an ultra low power voltage reference, an integrated high

impedance feedback divider network and an optimized Power Save Mode operation.

7.4.1.3 PWM Mode Operation

At moderate to heavy load currents, the device operates in PWM mode with continuos conduction. The switching

frequency is up to 1.6 MHz with a controlled frequency variation depending on the input voltage and load current.

If the load current decreases, the converter seamlessly enters Power Save Mode to maintain high efficiency

down to very light loads.

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Device Functional Modes (接下页)

7.4.1.4 Device Start-up and Soft Start

The step-down converter has an internal soft start to minimize inrush current and input voltage drop during start-

up. Once the device is enabled the device starts switching after a typical delay time of 1 ms. Then the soft start

time of typical 700 μs begins with a reduced current limit of typical 150mA. When this time expires the device

enters full current limit operation.

7.4.1.5 Automatic Transition Into 100% Mode

Once the input voltage comes close to the output voltage, the DC/DC converter stops switching and enters 100%

duty cycle operation. It connects the output V_OUTvia the inductor and the internal high side MOSFET switch to

the input VIN, once the input voltage V_INfalls below the 100% mode enter threshold, V_{TH_100-}. The DC/DC

regulator is turned off, switching stops and therefore no output voltage ripple is generated. Because the output is

connected to the input, the output voltage follows the input voltage minus the voltage drop across the internal

high side switch and the inductor. Once the input voltage increases and trips the 100% mode exit threshold,

V_{TH_100+}, the DC/DC regulator turns on and starts switching again.

7.4.2 Step-Up Converter

7.4.2.1 Enable and Shutdown

The device is turned on with EN2/PWM = high. With EN2/PWM = low the device enters shutdown mode. In

constant current step-up mode (BM = high) the pin EN2/PWM has to be pulled to low level for longer than t_{Dim_Off}

max to enter shutdown mode. This pin must be terminated.

7.4.2.2 Soft Start

The step-up converter begins soft start when the EN2/PWM pin is pulled high. At the beginning of the soft start

period, the isolation FET is turned on slowly to charge the output capacitor with 30-mA current for about 6 ms.

This is called the pre-charge phase. The output is charged up to the level of the input voltage VIN. After the pre-

charge phase, the device starts switching and the output voltage ramps up. This is called switching soft start

phase. An internal soft start circuit limits the peak inductor current.

7.4.2.3 Power Save Mode

The step-up converter integrates a power save mode with pulse frequency modulation (PFM) to improve

efficiency at light load. When the load current decreases, the inductor peak current set by the output of the error

amplifier declines to regulate the output voltage. When the inductor peak current hits the low limit of 240 mA, the

output voltage will exceed the set voltage as the load current decreases further. The device enters power save

mode once the FB voltage exceeds the PFM mode threshold, which is 1% above the nominal output voltage. It

stops switching, the load is supplied by the output capacitor and the output voltage begins to decline. When the

FB voltage falls below the PFM mode threshold voltage, the device starts switching again to ramp up the output

voltage.

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Device Functional Modes (接下页)

Output

Voltage

PFM mode at light load

PFM mode threshold

1.01 x V_{OUT_NOM}

V_{OUT_NOM}

PWM mode at heavy load

图 6. Output Voltage in PFM and PWM Mode

7.4.2.4 PWM Mode

The step-up converter uses a quasi-constant 1.0-MHz frequency pulse width modulation (PWM) at moderate to

heavy load current. Based on the input voltage to output voltage ratio, a circuit predicts the required off-time. At

the beginning of the switching cycle, the NMOS switching FET is turned on. The input voltage is applied across

the inductor and the inductor current ramps up. In this phase, the output capacitor is discharged by the load

current. When the inductor current hits the current threshold that is set by the output of the error amplifier, the

PWM switch is turned off, and the power diode is forward-biased. The inductor transfers its stored energy to

charge the output capacitor and supply the load. When the off-time is expired, the next switching cycle starts

again. The error amplifier compares the FB pin voltage with an internal reference voltage, and its output

determines the inductor peak current.

7.4.2.5 Constant-Current Step-Up Mode Operation

With pin BM = high the converter can regulate to a constant output current. The internal reference voltage is

therefore reduced to 200mV. In order to regulate a constant output current, a sense resistor has to be connected

between pin FB and GND, see 图 7. The device features in this operation mode a PWM to analog converter at

pin EN2/PWM. The internal reference voltage is scaled according to the duty cycle of the PWM signal applied to

pin EN2/PWM, see 图 8. When the pin EN2/PWM is pulled low longer than t_{Dim_OFF}max, the step-up converter

enters shutdown mode. The constant output current I_OUT2can be calculated according equations 公式 1 and 公式

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Device Functional Modes (接下页)

Step up Converter

VIN

I_OUT

VO2

PFM/PWM

Control

C_OUT2

SW2

V_FB

V_BAT

V_FB

V_REF

C_IN

Error

Amplifier

R_Sense

t_{Dim_On}

PWM to analog converter

V_REF= D_PWM* 200mV

EN2/PWM

t_{Dim_Off}

PWM

GND2

图 7. Step-Up Converter in Constant-Current Operation Mode

EN2/PWM

PWM Dimming

Device

Shutdown

t_{Dim_On}t_{Dim_OFF}

t_{Dim_OFF}

t_{Dim_OFF}max

200

160

120

V_FBin

t_{Dim_On}

D =

t_{Dim_On}

Dim_OFF

100

D in %

图 8. EN2/PWM Pin Function

V_FB

I_{OUT 2}

R_Sense

(1)

(2)

200mV

I_{OUT 2}= D_PWM

R_Sense

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Device Functional Modes (接下页)

7.4.2.6 Constant-Voltage Step-Up Mode Operation

With pin BM = low the converter operates as a constant output voltage step-up converter. The internal reference

voltage is set to 795 mV. A feedback resistor divider need to be connected between VOUT, FB and GND with its

tap point connected to FB pin. The device provides a fixed set 12 V output voltage if the FB pin is connected to

VIN. In this case no external resistor divider network is needed.

8 Application and Implementation

注

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

8.1 Application Information

The TPS62770 is a tiny power solution for wearable applications including a 370nA ultra low Iq step-down

converter, a slew rate controlled load switch and a dual mode step-up converter. The output voltage of the step-

down converter can be selected between 1.0V and 3.0V. The output voltage can be changed during operation. In

shutdown mode, the output of the step-down converter is pulled to GND. The integrated load switch is internally

connected to the output of the step-down converter and features slew rate control during turn on phase. Once

turned off, its output is connected to GND.

The dual mode step-up converter can generate a constant output voltage up to 15V, e.g. for PMOLED supply, or

a constant output current, e.g. for LED back light supply. The output voltage can be adjusted up to 15V with

external resistors, or set to fixed 12V by connecting the FB pin to VIN. The device features an internal over

voltage protection of 17V in case the FB node is left open or tight to GND. It includes an internal rectifier and

load disconnect function. When used as constant output current driver, the device offers a PWM to analog

converter to scale down the reference voltage according to the duty cycle of the PWM signal.

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8.2 Typical Application

8.2.1 System and PMOLED Supply

TPS62770

VOUT1 = 1.8V/300mA

L1 = 2.2mH

VIN

SW1

VO1

MCU / BLE

DC/DC 1

Step Down Converter

EN1

C_IN

10mF

C_OUT1

VSEL3

VSEL2

VSEL1

10mF

Load Output = 1.8V

LOAD

Sensors

ON/OFF

CTRL

Load Switch

L2 = 10mH

VOUT2 = 9.6V

SW2

VO2

PMOLED

EN2/PWM

DC/DC 2

Step up converter

R₁=

910k

C_OUT2

10mF

R₂=

82k

GND1

GND2

图 9. Step-Up Converter with Adjustable Output Voltage

spacer

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Typical Application (接下页)

TPS62770

VOUT1 = 1.8V/300mA

L1 = 2.2mH

VIN

SW1

VO1

MCU / BLE

DC/DC 1

Step Down Converter

EN1

C_IN

10mF

C_OUT1

VSEL3

VSEL2

VSEL1

10mF

Load Output = 1.8V

LOAD

VO2

Sensors

ON/OFF

CTRL

Load Switch

L2 = 10mH

VOUT2 = 12V / 30mA

SW2

EN2/PWM

PMOLED

DC/DC 2

Step up converter

C_OUT2

10mF

GND1

GND2

图 10. Step-Up Converter with Fixed 12-V Output

8.2.1.1 Design Requirements

The device is supplied by an input voltage between 2.5V and 5.5V. In wearable personal electronics this is

usually a rechargeable Li-Ion battery / USB port. The step-down converter supplies the system (MCU/BLE radio).

In order to supply a PMOLED display, the step-up converter must be configured to operate in constant output

voltage mode with BM pin tied to GND before the step-up converter is enabled. Ideally the BM pin is hardwired to

GND. The output voltage of the step-up converter is either set by an external resistor divider network (R1/R2),

shown in 图 9. The step-up converter supports an internally fixed 12V output voltage by connecting the FB pin to

VIN, shown in 图 10.

The LOAD output is internally connected to the output of the buck regulator and can supply a sensor or a sub-

system, which are temporarily used. In order to achieve better supply voltage decoupling / noise reduction a

capacitor can be connected on the LOAD output.

The design guideline provides a component selection to operate the device within the recommended operating

conditions. 表 2 shows the components used for the application characteristic curves.

表 2. Components for Application Characteristic Curves

PACKAGE CODE / SIZE

REFERENCE

CIN

DESCRIPTION

VALUE

10 µF

10 uF

MANUFACTURER

Murata

[mm x mm x mm]

Ceramic capacitor X5R 6.3V,

GRM155R60J106ME11

0402 / 1.0 x 0.5 x 0.5

Ceramic capacitor X5R 6.3V,

GRM155R60J106ME11

COUT1

COUT2

0402 / 1.0 x 0.5 x 0.5

0603 / 1.6 x 0.8 x 0.8

Murata

Ceramic capacitor X5R 25V,

GRM188R61E106MA73

Murata

Inductor DFE201610C

Inductor VLS302515

2.2 µH

10 µH

2.0 x 1.6 x 1.0

3.0 x 2.5 x 1.5

Toko

TDK

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8.2.1.2 Application Curves Step-Down Converter

VIN = 3.6V

VIN = 4.2V

VIN = 5.0V

VIN = 3.6V

VIN = 4.2V

VIN = 5.0V

0.001

0.01

0.1

100

0.001

0.01

0.1

100

IOUT [mA]

图 12. Efficiency vs. IOUT, VOUT1 = 1.2 V

图 11. Efficiency vs. IOUT, VOUT1 = 1.0 V

100

VIN = 3.6V

VIN = 4.2V

VIN = 5.0V

VIN = 4.2V

VIN = 5V

0.001

0.01

0.1

100

0.001

0.01

0.1

100

IOUT [mA]

图 14. Efficiency vs. IOUT, VOUT1 = 3.0 V

图 13. Efficiency vs. IOUT, VOUT1 = 1.8 V

1400

1200

1000

800

600

400

200

1.890

1.872

1.854

1.836

1.818

1.800

1.782

1.764

1.746

1.728

1.710

VIN = 3.0V

VIN = 3.6V

VIN = 4.2V

VIN = 5V

VIN = 3.0V

VIN = 3.6V

VIN = 4.2V

VIN = 5V

100

150

200

250

300

0.01

0.10

1.00

10.00

100.00

IOUT1 [mA]

图 15. F_SWvs. IOUT1, VOUT1 = 1.1 V

图 16. VOUT1 = 1.8 V vs IOUT1

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V_IN= 3.6V

V_OUT= 1.2V

I_OUT= 50 µA

V_IN= 3.6V

V_OUT= 1.2V

I_OUT= 1 mA

图 17. Typical Operation in Power Save Mode

图 18. Typical Operation in Power Save Mode

V_IN= 3.6V

I_OUT= 50 mA

V_IN= 3.6V

I_OUT= 200 mA

V_OUT= 1.2V

图 19. Typical Operation in Power Save Mode

图 20. Typical Operation in PWM Mode

V_IN= 3.6V

I_OUT= 5mA to

V_IN= 3.6V

I_OUT= 5mA to

200mA

V_OUT= 1.2V

1 µs rise/fall time

V_OUT= 1.2V

sinusodial I_OUTsweep

图 21. Load Transient Performance

图 22. AC Load Regulation Performance

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V_IN= 3.6V

I_OUT= 0mA

V_IN= 3.6V

I_OUT= 0mA

V_OUT= 1.8V

EN altered from low to high

图 23. Startup After EN High

图 24. VOUT Ramp Up

V_IN= 0 V to 3.6 V

in 100 µs

EN = VIN

V_IN= 3.6V

I_OUT= 0mA

V_OUT= 1.8V

I_OUT= 0 mA

图 26. Output Discharge

图 25. VIN Ramp Up/Down

V_IN= 3.6V

V_OUT= 1.8V

I_OUT1= 5mA

R_LOAD= 150Ω

图 27. Output Load Enable/Disable

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8.2.1.3 Application Curves Step-Up Converter Constant 12 V/15 V Output Voltage

VIN = 4.2V

VIN = 3.6V

VIN = 3V

VIN = 5.0V

VIN = 4.2V

VIN = 3.6V

VIN = 3.0V

VIN = 5.0V

100

IOUT [mA]

C001

图 28. Efficiency vs. IOUT, VOUT = 15V

图 29. Efficiency vs. IOUT, VOUT = 12V

12.60

12.48

12.36

12.24

12.12

12.00

11.88

11.76

11.64

11.52

11.40

200

180

160

140

120

100

VIN = 4.2V

VIN = 3.6V

VIN = 3.0V

VO2 = 12V

VO2 = 15V

VO2 = 9V

0.1

100

1000

2.5

3.5

4.5

5.5

IOUT2 [mA]

VIN [V]

TA = 25°C

L = 10µH

typical switch current lmit I_{LIM_SW}

I_OUT2max @ -3% VOUT drop

COUT2 = 2x 10µF

图 30. VOUT2 = 12V vs IOUT2

图 31. Maximum Output Current vs VIN for Typical I_LIMSW

V_IN= 3.6V

V_OUT= 12V

I_OUT2= 2mA

L = 10µH

V_IN= 3.6V

I_OUT2= 30mA

L = 10µH

V_OUT= 12V

图 32. Typical Operation PFM Mode

图 33. Typical Operation PWM Mode

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V_IN= 3.6V

I_OUT2= 0 mA to 20 mA

L = 10µH

V_IN= 3.6 V

R_LOAD= 1 kΩ

V_OUT= 12V

V_OUT= 12 V

L = 10 µH

图 34. AC Load Regulation Performance

图 35. Startup after EN High

8.2.2 Step-Up Converter with 5-V Output Voltage

TPS62770

VOUT1 = 1.8V/300mA

L1 = 2.2mH

VIN

SW1

VO1

MCU / BLE

DC/DC 1

Step Down Converter

EN1

C_IN

10mF

C_OUT1

VSEL3

VSEL2

VSEL1

10mF

Load Output = 1.8V

LOAD

Sensors

ON/OFF

CTRL

Load Switch

VOUT2

= 5V/200mA

L2 = 4.7mH

SW2

VO2

EN2/PWM

DC/DC 2

Step up converter

R₁=

C_OUT2

2 x 10mF

R₂=

191k

GND1

GND2

图 36. Step-Up Converter Providing 5-V V_OUT2

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8.2.2.1 Design Requirements

表 3. Components for Application Characteristic Curves

PACKAGE CODE / SIZE

[mm x mm x mm]

REFERENCE

DESCRIPTION

VALUE

MANUFACTURER

Ceramic capacitor X5R 6.3V,

GRM155R60J106ME11

CIN

10 µF

0402 / 1.0 x 0.5 x 0.5

Murata

Ceramic capacitor X5R 25V,

GRM188R61E106MA73

COUT2 (2x)

10 uF

0603 / 1.6 x 0.8 x 0.8

3.0 x 2.5 x 1.5

Murata

TDK

Inductor VLS302515

4.7 µH

8.2.2.2 Application Curves

VIN = 3.0V

VIN = 3.6V

VIN = 4.2V

IOUT [mA]

100

图 38. Transient Response V_OUT2= 5 V

图 37. Efficiency vs. IOUT, VOUT = 5.0 V

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8.2.3 Step-Up Converter Operating with Constant Output Current

The step-up converter device can be configured to operate as a constant current driver e.g. to power 3 to 4 white

LED's in a string. The current through the string is set by the sense resistor R_Senseas shown in 图 39 To

minimize the losses in the sense resistor, the device features a 200mV internal reference. This section describes

an application delivering 10mA through an LED string with 4 LED's which is suitable for small display used in

wearable applications.

Step up Converter

VIN

I_OUT

VO2

PFM/PWM

Control

C_OUT2

L2 =

10mH

= 10mF

SW2

V_FB

V_BAT

V_REF

C_IN

Error

Amplifier

V_FB

= 10mF

R_Sense

= 20W

t_{Dim_On}

PWM to analog converter

V_REF= D_PWM* 200mV

EN2/PWM

t_{Dim_Off}

PWM

GND2

图 39. Step-Up Converter with Constant Output Current - Simplified Block Diagram

8.2.3.1 Design Requirements

The Sense resistor to set the maximum output current can be calculated according to 公式 3 The output current

IOUT2 can be reduced by applying a PWM signal at pin EN2/PWM according to 公式 4

2 0 0 m V

S e n s e

I _{O U T 2}

(3)

(4)

200mV

I_{OUT 2}= D_PWM

R_Sense

Where:

R_Sense= sense resistor in [Ω]

I_OUT2= output current in [mA]

D_PWM= Dutycycle of the PWM singal at pin EN2/PWM

表 4. Components for Application Characteristic Curves

PACKAGE CODE / SIZE

[mm x mm x mm]

REFERENCE

CIN

DESCRIPTION

VALUE

10 µF

10 uF

MANUFACTURER

Murata

Ceramic capacitor X5R 6.3V,

GRM155R60J106ME11

0402 / 1.0 x 0.5 x 0.5

Ceramic capacitor X5R 25V,

GRM188R61E106MA73

COUT2

0603 / 1.6 x 0.8 x 0.8

3.0 x 2.5 x 1.5

Murata

Inductor VLS302515

LED LTW-E670DS

10 µH

n/a

TDK

D1-D4

Lite ON

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8.2.3.2 Detailed Design Procedure

8.2.3.2.1 Setting The Output Voltage Of The Step-Down Converter

The output voltage is set with the VSEL1-3 pins according to Table 1. No further external components are

required.

8.2.3.2.2 Programming the Output Voltage Of The Step-Up Converter

There are two ways to set the output voltage of the step-up converter. When the FB pin is connected to the input

voltage, the output voltage is fixed to 12 V. This function reduces the external components to minimize the

solution size. The second way is to use an external resistor divider to set the desired output voltage.

By selecting the external resistor divider R1 and R2, as shown in 公式 5, the output voltage is programmed to the

desired value. When the output voltage is regulated, the typical voltage at the FB pin is V_REFof 795 mV.

≈

∆

’

V_OUT

V_REF

R1=

Where:

-1 ìR2

◊

(5)

V_OUTis the desired output voltage

V_REFis the internal reference voltage at the FB pin

8.2.3.2.3 Recommended LC Output Filter

表 5. Recommended LC Output Filter Combinations for the Step-Down

Converter

OUTPUT CAPACITOR VALUE [µF]⁽²⁾

INDUCTOR VALUE

[µH]⁽¹⁾

10 µF

22 µF

(3)

2.2

√

(1) Inductor tolerance and current de-rating is anticipated. The effective inductance can vary by 20% and -

30%.

(2) Capacitance tolerance and bias voltage de-rating is anticipated. The effective capacitance can vary by

20% and -50%.

(3) This LC combination is the standard value and recommended for most applications.

表 6. Recommended LC Output Filter Combinations for Step-Up Converter

INDUCTOR

VALUE

OUTPUT CAPACITOR VALUE [µF]⁽²⁾

VOUT

IOUT

[µH]⁽¹⁾

10 µF

2 x 10µF

(3)

(IOUT ≤ 30 mA)

(IOUT ≤ 100 mA)

(IOUT ≤ 200 mA)

√

9 V –15 V

5 V

(3)

√

(3)

4.7

√

(1) Inductor tolerance and current de-rating is anticipated. The effective inductance can vary by 20% and -

30%.

(2) Capacitance tolerance and bias voltage de-rating is anticipated. The effective capacitance can vary by

20% and -50%.

(3) This LC combination is the standard value and recommended for most applications.

8.2.3.2.4 Inductor Selection Step-Down Converter

The inductor value affects its peak-to-peak ripple current, the PWM-to-PFM transition point, the output voltage

ripple and the efficiency. The selected inductor has to be rated for its DC resistance and saturation current. The

inductor ripple current (ΔI_L) decreases with higher inductance and increases with higher V_INor V_OUTand can be

estimated according to 公式 6.

公式 7 calculates the maximum inductor current under static load conditions. The saturation current of the

inductor should be rated higher than the maximum inductor current, as calculated with 公式 7. This is

recommended because during a heavy load transient the inductor current rises above the calculated value. A

more conservative way is to select the inductor saturation current above the high-side MOSFET switch current

limit, I_LIMF

TPS62770

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

www.ti.com.cn

Vout

Vin

DI_L= Vout ´

L ´ ¦

(6)

(7)

= I

Lmax

outmax

With:

f = Switching Frequency

L = Inductor Value

ΔI_L= Peak to Peak inductor ripple current

I_Lmax= Maximum Inductor current

In DC/DC converter applications, the efficiency is essentially affected by the inductor AC resistance (i.e. quality

factor) and by the inductor DCR value. Increasing the inductor value produces lower RMS currents, but degrades

transient response. For a given physical inductor size, increased inductance usually results in an inductor with

lower saturation current.

The total losses of the coil consist of both the losses in the DC resistance (R_DC) and the following frequency-

dependent components:

•

The losses in the core material (magnetic hysteresis loss, especially at high switching frequencies)

Additional losses in the conductor from the skin effect (current displacement at high frequencies)

Magnetic field losses of the neighboring windings (proximity effect)

Radiation losses

8.2.3.2.5 Inductor Selection Step-Up Converter

The step-up converter is optimized to work with an inductor values of 10 µH. Follow 公式 8 to 公式 10 to

calculate the inductor’s peak current for the application. To calculate the current in the worst case, use the

minimum input voltage, maximum output voltage, and maximum load current of the application. To have enough

design margin, choose the inductor value with -30% tolerance, and a low power-conversion efficiency for the

calculation.

In a step-up regulator, the inductor dc current can be calculated with 公式 8.

V_OUTìI_OUT

I_L(DC)

V ì h

(8)

Where:

V_OUT= output voltage

I_OUT= output current

V_IN= input voltage

η = power conversion efficiency, use 80% for most applications

The inductor ripple current is calculated with the 公式 9 for an asynchronous step-up converter in continuous

conduction mode (CCM).

ì V

+ 0.8V - V

(

)

OUT IN

DI_L(P-P)

L ì f_SWì V

+ 0.8V

(

)

OUT

(9)

Where:

ΔI_L(P-P)= inductor ripple current

L = inductor value

f _SW= switching frequency

V_OUT= output voltage

V_IN= input voltage

Therefore, the inductor peak current is calculated with 公式 10.

TPS62770

www.ti.com.cn

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

DI_{L P-P}

(

)

I_{L P}= I_{L DC}

(

)

(

)

(10)

The following inductor series from different suppliers have been used:

表 7. List Of Inductors

DIMENSIONS

INDUCTOR

SUPPLIER⁽¹⁾

TYPE

CONVERTER

INDUCTANCE [µH]

[mm³]

Step-down

2.2

2.9 x 1.6 x 1.0

2.0 × 1.25 × 1.0

DFE201610C

TOKO

FDK

MIPSZ2012D

2R2

2.2

2.0 x 1.2 x 1.0

MDT2012CH2R

TOKO

Step-up

2.0x1.6x1.2

3.0 x 2.5 x 1.5

2.0 x 1.6 x 1.5

VLS201610

VLS302515

VLS201612

TDK

4.7

(1) See Third-party Products Disclaimer

8.2.3.2.6 DC/DC Input and Output Capacitor Selection

Ceramic capacitors with low ESR values have the lowest output voltage ripple and are recommended. The

output capacitor requires either an X7R or X5R dielectric. Y5V and Z5U dielectric capacitors, aside from their

wide variation in capacitance over temperature, become resistive at high frequencies. At light load currents, the

converter operates in Power Save Mode and the output voltage ripple is dependent on the output capacitor value

and the PFM peak inductor current. A 10 µF ceramic capacitor is recommended as input capacitor.

表 8 shows a list of tested input/output capacitors.

表 8. List Of Capacitors

PACKAGE CODE / SIZE

REFERENCE

CIN

DESCRIPTION

VALUE

10µF

10uF

MANUFACTURER⁽¹⁾

Murata

[mm x mm x mm]

Ceramic capacitor X5R 6.3V,

GRM155R60J106ME11

0402 / 1.0 x 0.5 x 0.5

Ceramic capacitor X5R 6.3V,

GRM155R60J106ME11

COUT1

0402 / 1.0 x 0.5 x 0.5

0603 / 1.6 x 0.8 x 0.8

Murata

Ceramic capacitor X5R 25V,

GRM188R61E106MA73

Murata

COUT2

Ceramic capacitor X5R 6.3V,

GRM188R60J106ME84

10uF

Murata

(1) See Third-party Products Disclaimer

TPS62770

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

www.ti.com.cn

8.2.3.3 Application Curves

V_IN= 3.6V

EN2/PWM = high

R_Sense= 20Ω

4 LEDs in series

L = 10µH

V_IN= 3.6V

R_Sense= 20Ω

4 LED's in series

L = 10µH

t_{Dim_On}= 75 µs, t_{Dim_Off}= 75µs

D = 50%, T_DIim= 140µs, I_LED= 5mA

D = 100%, I_LED= 10mA

图 40. Constant Current Operation with EN2/PWM = 100%

图 41. Constant Current with EN2/PWM = 50% D

4 LED

3 LED

100

D [%]

V_IN= 3.6V

T_A= 25°C

R_Sense= 20 Ω

LED's in string configuration

L = 10 µH

T_DIim= 50 µs (F = 20kHz)

V_IN= 3.6V

R_Sense= 20 Ω

4 LED's in series

L = 10 µH

t_{Dim_On}= 15 µs, t_{Dim_Off}= 135 µs

D = 10%, T_DIim= 140 µs, I_LED= 1 mA

图 43. Constant Current vs D

图 42. Constant Current with EN2/PWM = 10% D

TPS62770

www.ti.com.cn

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

9 Power Supply Recommendations

The power supply must provide a current rating according to the supply voltage, output voltage and output

current of the TPS62770.

10 Layout

10.1 Layout Guidelines

•

As for all switching power supplies, the layout is an important step in the design. Care must be taken in board

layout to get the specified performance.

If the layout is not carefully done, the regulator could show poor line and/or load regulation, stability issues as

well as EMI problems and interference with RF circuits.

It is critical to provide a low inductance, impedance ground path. Therefore, use wide and short traces for the

main current paths.

The input capacitor should be placed as close as possible to the IC pins VIN and GND. The output capacitors

should be placed close between VO1/2 and GND pins.

The VO1/2 line should be connected to the output capacitor and routed away from noisy components and

traces (e.g. SW line) or other noise sources.

See 图 44 and 图 45 for the recommended PCB layout.

10.2 Layout Example

VOUT2

(Step Up Converter)

C_OUT2

SW2

VO2

GND2

VSEL3

GND

EN2/

PWM

BM VSEL2

TPS62770

SW1

VIN

EN1 VSEL1 CTRL

LOAD

GND1

VO1

VIN

C_IN

C_OUT1

VOUT1

(Step Down Converter)

图 44. Recommended PCB Layout with 12 V Fixed VOUT2

TPS62770

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

www.ti.com.cn

Layout Example (接下页)

VOUT2

(Step Up Converter)

C_OUT2

VSEL3

SW2

VO2

GND2

EN2/

PWM

VSEL2

GND

SW1

VIN

EN1 VSEL1 CTRL

GND1

LOAD

VO1

TPS62770

C_OUT1

C_IN

VIN

VOUT1

(Step Down Converter)

GND

图 45. Recommended PCB Layout with Adjustable VOUT2

TPS62770

www.ti.com.cn

ZHCSEV1A –FEBRUARY 2016–REVISED MARCH 2016

11 器件和文档支持

11.1 器件支持

11.1.1 开发支持

11.1.1.1 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 文档支持

11.2.1 相关文档ꢀ

另请参见《TPS62770EVM-734 评估模块用户指南》（文献编号：SLVUAO2）和应用笔记《精确测量超低 IQ 器

件的效率》（文献编号：SLYT558）。

11.3 商标

All trademarks are the property of their respective owners.

11.4 静电放电警告

这些装置包含有限的内置 ESD 保护。存储或装卸时，应将导线一起截短或将装置放置于导电泡棉中，以防止 MOS 门极遭受静电损

伤。

11.5 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。欲获得该数据表的浏览器版本，请查阅左侧的导航栏。

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)

TPS62770YFPR

TPS62770YFPT

ACTIVE

DSBGA

YFP

3000 RoHS & Green

250 RoHS & Green

SNAGCU

Level-1-260C-UNLIM

-40 to 85

62770

SNAGCU

⁽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 OPTION ADDENDUM

www.ti.com

10-Dec-2020

Addendum-Page 2

D: Max = 1.612 mm, Min =1.552 mm

E: Max = 1.612 mm, Min =1.552 mm

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邮寄地址：Texas Instruments, Post Office Box 655303, Dallas, Texas 75265

TPS62770 [TI]

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