functional block diagram - analog devices

AN-861APPLICATION NOTE

One Technology Way • P.O. Box 9106 • Norwood, MA 02062-9106, U.S.A. • Tel: 781.329.4700 • Fax: 781.461.3113 • www.analog.com

ADP1653 Evaluation and Test Methods

by Leo Chou and Adrian Fox

Rev. 0 | of 20

GENERAL DESCRIPTION This application note presents some methods used in evaluating the ADP1653 white LED driver. The ADP1653 evaluation board, sold by Analog Devices, Inc., is used during the evaluation, but users may choose to design their own evaluation boards. For simplicity, however, all the testing procedures in this application note are based on the Analog Devices ADP1653 evaluation board.

The ADP1653 evaluation board is designed specifically for the purpose of evaluation. There are numerous jumpers and test points on the board for users to measure currents, voltages, or probe important nodes.

There are also switches on the board that allow users to easily change voltages at certain pins. Note, however, that even though this application note is based on the ADP1653 evaluation board, it is not a user manual that shows how to use the board and the included software. For more details, see the document ADP1653 Flash LED Driver Evaluation Board Manual.

FUNCTIONAL BLOCK DIAGRAM

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1D

5R

19

D6

R20

D7

R23

ADI USB/I2C INTERFACE 0.4

VIC

0632

0-00

1

INT

INT

Figure 1.

http://www.analog.com/adp1653_evalboard

AN-861

Rev. 0 | of 20

TABLE OF CONTENTS General Description ......................................................................... 1 Functional Block Diagram .............................................................. 1 Board Schematics.............................................................................. 3

Motherboard ................................................................................. 3 Daughter Board ............................................................................ 4

General Considerations ................................................................... 5 Cables ............................................................................................. 5 Ammeter........................................................................................ 5 Temperature Measurement ......................................................... 5

Evaluation Methods ......................................................................... 6 Shutdown Current........................................................................ 6 VDD Soft Power-Down Current................................................... 7 VDD Operating Current ILED Register = 001 ........................... 8

VDD Operating Current HPLED Register = 001 (Boost Not Running, One LED) ......................................................................9 VDD Operating Current HPLED Register = 001 (Boost Running, Two LEDs) ................................................................. 10 Undervoltage Lockout Threshold (UVLO) ............................ 11 OUT Overvoltage Threshold.................................................... 12 LX Switching Frequency............................................................ 13 OUT Soft Start Ramp ................................................................ 14 Start-Up Inrush Current............................................................ 15 Efficiency..................................................................................... 16 Current Limit .............................................................................. 18 Line Regulation........................................................................... 19

AN-861

Rev. 0 | of 20

BOARD SCHEMATICS MOTHERBOARD

5V U

SB

IC_V

DD

VB

AT_

M

3.3V

3.3V

3.3V

3.3V

3.3V

3.3V

IC_V

DD

3.3V

GPI

O1

GPI

O2

INT

GPI

O2

GPI

O1

IC_V

DD

SCL1

SD

A1

IC_V

DD

EN

IC_V

DD

SCL1

STR

3.3V

5V U

SB

1.8V

VB

AT_

M

IC_V

DD

SCL1

STR

SD

A1

IC_V

DD

IC_V

DD

1.8V

3.3V

3.3V

5V U

SB

VB

AT_

M

I2 C C

ON

TRO

L LI

NE

S

STR

OB

E !

SW

ITC

H B

RIN

GS

STR

HIG

HFO

R F

LAS

H !

SW P

USH

BU

TTO

N

STR

OB

E !

ENA

BLE

GPI

O1

2 H

EA

DE

RS

US

ED

FO

R M

ECH

AN

ICA

L ST

AB

ILIT

Y1

ON

MO

THE

R, D

AU

GH

TER

GPI

O2

JP21

HE

AD

ER

10

1 2 3 4 5 6 7 8 9 10

1 2 3 4 5 6 7 8 9 10

JP20

HE

AD

ER 1

0

1 2 3 4 5 6 7 8 9 10

1 2 3 4 5 6 7 8 9 10

TP14 SC

L

C18

100n

FC

141n

F

C9

6.2p

F

U5

AD

P171

5-1.

8

EN IN OU

T

SSG

ND

1

GN

D2

GN

D3

GN

D4

JP8

HEA

DE

R L

AR

GE

10 ×

2

12

34

56

78

910

1112

1314

1516

1718

1920

C21

2.2µ

F

S13

4

21

D6*

LED

D5

LED

C13

100n

F

C6

100n

FY1

CR

YSTA

L1423

14

C10

10nF

U4

M24

C64

-R

A0

A1

A2

VSSSDA

SCL

WP

VCCR

63*

C31

47µF

C17

100n

F

R51

*

TP15SD

A

JP6

EN1

12

23

3

R20

*

R24

2.2kΩ

R25

2.2kΩ

R22

10kΩ

R23

*

C15

100n

F

R19

*

R34

*10

5kΩ

R30

100kΩ

R65

*

C5

100n

F

JP9

SETF

D8

LED

R64

*

U2

CY7

C68

013A

RD

Y0/S

LRD

RD

Y1/S

LWR

AVC

C1

XTA

LOU

T

XTA

LIN

AG

ND

1

AVC

C2

D+

D–

AG

ND

2

VCC

1

GN

D1

IFC

LK

RES

1 2 3 4 5 6 7 8 9 10 11 12 13 14

SCL

SDA

VCC2

PB0/FD0

PB1/FD1

PB2/FD2

PB3/FD3

PB4/FD4

PB5/FD5

PB6/FD6

PB7/FD7

GND2

VCC3GND3

15

16

17

18

19

20

21

22

23

24

25

26

27

28

CTL

029

CTL

130

CTL

231

VCC

432

PA0/

INT1

33PA

1/IN

T134

PA3/

*WU

236

PA4/

FIFO

AD

R0

37PA

5/FI

FOA

DR

138

PA6/

*PK

TEN

D39

PA7/

*FLA

G40

GN

D4

41R

ESET

42

PA2/

*SLO

E35

VCC543*WAKEUP44

PD0/FD845PD1/FD946PD2/FD947

PD3/FD1048PD4/FD1149PD5/FD1250PD6/FD1351PD7/FD1452

GND553CLKOUT54

VCC655GND656

PAD

PAD

JP5 US

B M

INI B

VDD D–

D+ ID

GN

DSH

ELL

1 2 3 4 5 6

C11

2.2u

F

D7*

LED

R32

105kΩ

JP10

SCL/

CTR

L1

JP7

HE

AD

ER L

AR

GE

88

76

54

32

1C

502.

2µF

R62

*

R35

*0Ω

R31

1kΩ

R66

*

U3 AD

P330

3- 3

.3

OU

T1

OU

T2NR

GN

DSD ER

R

IN2

IN1

C30

100n

F

R27

100kΩ

R26

220kΩ

C8

6.2p

F

C16

100n

F

3.3V

EN

INT

INT

3.3V

C7

10µF

R21

100kΩ

SD

A1

R33

*10

5kΩ

JP11

SD

A/C

TRL0

1122

33

TP21

GN

D

TP20

1.8V

TP19

VB

AT

TP18

IC_V

DD

TP17

USB

TP16

3.3V

C19

100n

F3.3V 1.

8V

JP12

IC_V

DD

11

12

23

3JP

13

IC_V

DD

21

12

23

3IC

_VD

D

C12

1µF

3.3V

C51

100n

F

C20

2.2µ

F

06320-002

1122

3311

2233

*NO

T PO

PULA

TED

NO

TES

1. D

EC

OU

PLI

NG

FO

R E

AC

H O

F 6

6801

3A D

IGIT

AL

INP

UTS

, 040

2 C

AP

S P

LAC

ED

AS

CLO

SE

AS

PO

SS

IBLE

TO

EA

CH

PIN

. GR

OU

ND

IS C

OM

MO

N G

RO

UN

D T

O A

GN

D

AT

1 P

OIN

T. N

O G

RO

UN

D D

ISTI

NC

TIO

N IN

SC

HEM

ATI

C.

2. IC

_VD

D IS

TH

E D

IGIT

AL

INTE

RFA

CE

SUPP

LY V

OLT

AG

E—IC

_VD

D

SH

OU

LD B

E C

ON

NE

CTE

D T

O E

ITH

ER

5V,

3.3

V, 1

.8V

OR

VB

ATT

U

SIN

G J

4, J

5.3.

R33

, R34

, R35

CA

N B

E A

DD

ED

IN H

W M

OD

E T

O A

LLO

W F

AS

T TR

AN

SIT

ION

S B

ETW

EE

N S

TATE

S

Figure 2. Motherboard Schematics

AN-861

Rev. 0 | of 20

DAUGHTER BOARD

VBA

T

OU

T

VBA

T

OU

T

POW

ER S

ECTI

ON LX

NO

DE

TP1

CA

PAC

ITO

R/T

VS D

IOD

ES C

AN

BE

PLA

CED

HER

E FO

R E

SD P

RO

TEC

TIO

N.

INTF

= G

ND

, I2 C

MO

DE

INTF

= H

I, H

W M

OD

E

D4

IND

ICA

TOR

LED

JP3

INTF

11

22

33

HPL

ED

PGN

D

D1

12

L1 2.2µ

H

12

D10

WH

ITE-

LED

D9

SHA

RP

LED

C1

1

A1

2

A2

3

C2

4C

35

A3

6

A4

7

C4

8

D2

WH

ITE-

LED

C1

4.7 µ

F

C2

4.7 µ

F

U1

AD

P165

3

SET

T1

SE

TF2

CTR

L1/S

CL

3

CTR

L0/S

DA

4

SETI5

ILED6

OUT7

GND8H

PLE

D9

INTF

10

INT

11

PGN

D12

LX13

VDD14

EN15

STR16

PA

D17

VBA

T

J1J8

J2TP2

J3

OU

T

TP3

PGN

D

VB

AT

VIC

_D

VIC

_D

EN STR

INT

CTR

L1/S

CL

CTR

L0/S

DA

TxM

ASK

JP1 1 3 5 7 9 11 13 15 17 19

2 4 6 8 10 12 14 16 18 20

JP2

88

77

66

55

44

33

22

11

99

1010

J6

RA

ND

OM

AG

ND

TES

TPO

INTS

FO

R D

IGIT

AL

SIG

NA

LS.

TP10

AG

ND

TP11

AG

ND

TP12

AG

ND

TP13

AG

ND

VB

AT

VIC

_D

VIC

_D

CTR

L1/S

CL

J7

TP4

CTR

L0/S

DA

R4

332kΩ

R5

105kΩ

R6

47kΩ

TP5

R1

0Ω

R2

10kΩ

R3

47kΩ

VIC

_DJ5

VIC

_DJ4

D3

WH

ITE-

LED

C3

*

VB

AT

06320-003

*NO

T P

OP

ULA

TED

ON

TH

E B

OA

RD

.

NO

TES

1. G

ND

(IC

), P

GN

D S

HO

ULD

BE

CO

NN

EC

TED

AT

A S

ING

LE P

OIN

T.

Figure 3. Daughter Board Schematics

AN-861

Rev. 0 | of 20

GENERAL CONSIDERATIONSCABLES Because the ADP1653 is a high current, high power device, the cables used to connect the power supply to the chip must be as thick and short as possible to minimize the series resistance. However, no matter how short and thick a cable is, it still has a finite resistance, and the voltage at the VBAT pin is lower than the power supply voltage. For example, if the cable resistance is 0.1 Ω and the input current is 1 A, there is a 0.1 V drop between the power supply and the VBAT pin. That means if the supply is set to 2.8 V, the chip gets only 2.7 V, and, in some cases, this can trigger the UVLO.

Users are, therefore, advised to take into account the IR drop across cables. It is recommended that the voltage be measured at VBAT with a voltmeter and the supply adjusted until the desired VBAT voltage is obtained.

AMMETER Even though an ammeter is convenient to use, because of the large current levels in power devices its internal resistance could cause incorrect measurements. As a result, care must be taken when using an ammeter.

Users should ensure that the scale is set to the order of magnitude of the current being used to minimize the series resistance of the ammeter. For example, when measuring a current that is expected to be on the order of hundreds of microamperes, the scale should be set to hundreds of microamperes or a few milliamperes.

If the current measured is going to be high (hundreds of milliamperes or even amperes), then using an ammeter could cause a significant error. In such cases, a small, high precision power resistor should be used. A good choice is a 1%, 0.1 Ω power strip that has a rating of several amps. Then, measuring the voltage across the resistor and dividing it by the resistance gives the current reading.

TEMPERATURE MEASUREMENT Because the Cypress CY7C68013A chip on the motherboard is not rated at −40°C, it is not recommended to subject the mother-board to temperature testing. As a result, a ribbon cable is provided so users can separate the motherboard and daughter board for temperature measurement. Connect both ends of the ribbon cable to the headers on the motherboard and daughter board and place only the daughter board under temperature stress.

AN-861

Rev. 0 | of 20

EVALUATION METHODS SHUTDOWN CURRENT To measure the shutdown current, connect an ammeter in series with the power supply and the VBAT pin. The ammeter should have enough resolution to measure down to tens of nanoamperes. Otherwise, it is difficult to distinguish the actual current from noise.

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-00

4

INT

VOLTMETER

VOLTMETERTO CHECK ACTUAL

VBAT VOLTAGE

SHORT THIS JUMPERTO SET PART TOI2C MODE

SHORT ENTO L

AMMETER

AMMETERTO MEASURE

INPUT CURRENT

POWERSUPPLY

2.7V TO 5.5V,2.0A SUPPLYOR BATTERY

SHORT SCL, SDA,AND TxMASK TO H

SHORTVIC

TO 3.3V

NOTES1. USE THICK, SHORT CABLES.

SHORTTHISJUMPER

INT

Figure 4. Measuring Shut-Down Current

AN-861

Rev. 0 | of 20

VDD SOFT POWER-DOWN CURRENT The VDD soft power-down current is the current that the part draws when it is enabled but not boosting. It is measured in the same way as the shutdown current.

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-00

5

INT


SHORT ENTO H

SHORT SCL, SDA,AND TxMASK TO H

SHORTVIC

TO 3.3V


SHORTTHISJUMPER

VOLTMETER


VBAT VOLTAGE

AMMETER

AMMETERTO MEASURE

INPUT CURRENT

POWERSUPPLY


INT

Figure 5. Measuring Soft Power-Down Current

AN-861

Rev. 0 | of 20

VDD OPERATING CURRENT ILED REGISTER = 001 The test setup for this is the same as that of the soft power-down current. With the device powered up, use the software to program 001 to the ILED register and read the supply current from the ammeter. To get an accurate reading, make sure the scale of the ammeter is set to larger than hundreds of microamperes.

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-00

6

INT


SHORT ENTO H

SHORT SCLAND SDA TO H

SHORTTxMASK TO L

SHORTVIC

TO 3.3V


VOLTMETER


VBAT VOLTAGE

AMMETER

AMMETERTO MEASURE

SUPPLY CURRENT

POWERSUPPLY


INT

Figure 6. Measuring Supply Current (ILED)

AN-861

Rev. 0 | of 20

VDD OPERATING CURRENT HPLED REGISTER = 001 (BOOST NOT RUNNING, ONE LED) This test measures the supply current when the HPLED register is set to 001, the ILED register is set to 0, and the part is not boosting. This means only one LED is on, and VBAT is greater than VOUT. To measure the supply current with boost disabled, place a jumper on J2 to short out one of the LEDs, and make sure the supply voltage is greater than the forward voltage of the diode.

The Tx mask voltage can be set to either HI, LO, or left floating. The current is different in each case. See the ADP1653 data sheet for more information on Tx mask.

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-00

7

INT

SHORT THISJUMPER TOSET PARTTO I2C MODE

SHORTTHISJUMPER

SHORTTHESEJUMPERS

SHORT ENTO H


SWITCH TxMASKTO DESIRED SETTING

SHORTVIC

TO 3.3V


VOLTMETER


VBAT VOLTAGE

AMMETER

AMMETERTO MEASURE

INPUT CURRENT

POWERSUPPLY


INT

Figure 7. Measuring Supply Current (HPLED—Boost Disabled)

AN-861

Rev. 0 | of 20

VDD OPERATING CURRENT HPLED REGISTER = 001 (BOOST RUNNING, TWO LEDs) This test measures the supply current when the HPLED register is set to 001, the ILED register is set to 0, and the part is boosting. Therefore, both LEDs should be on and Jumper J2 should not be shorted.

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-00

8

INT

SHORT THISJUMPERTO SET PARTTO I2C MODE

SHORTTHISJUMPER

SHORT THISJUMPER

SHORT ENTO H



SHORTVIC

TO 3.3V


VOLTMETER


VBAT VOLTAGE

AMMETER

AMMETERTO MEASURE

INPUT CURRENT

POWERSUPPLY


INT

Figure 8. Measuring Supply Current (HPLED—Boost Enabled)

AN-861

Rev. 0 | of 20

UNDERVOLTAGE LOCKOUT THRESHOLD (UVLO) The UVLO is the VBAT voltage required to turn on or turn off the part. There are two UVLOs: UVLO (VDD rising) is the voltage at which the part turns on, and UVLO (VDD falling) is the voltage at which the part turns off. To measure UVLO (VDD rising), apply a low voltage to the part and slowly increase it, 1 mV at a time. For each increase in the voltage steps, use the software to try to turn on the ILED.

The first voltage at which the ILED is able to turn on is the UVLO (VDD rising). To measure UVLO (VDD falling), power up the part and use the software to turn on the ILED. Then slowly decrease the supply voltage in 1 mV steps until the ILED turns off. The voltage at which turn-off occurs is the UVLO (VDD falling).

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-00

9

INT


SHORTTHESEJUMPERS

SHORT THISJUMPER

SHORT ENTO H

LIGHTILED UP



SHORTVIC

TO 3.3V


VOLTMETER


VBAT VOLTAGE

AMMETER

AMMETERTO MEASURE

INPUT CURRENT

POWERSUPPLY


INT

Figure 9. Measuring UVLO (Rising and Falling)

AN-861

Rev. 0 | of 20

OUT OVERVOLTAGE THRESHOLD The ADP1653 has a safety feature that turns itself off when the voltage at the OUT pin rises above 10.2 V (nominal).

To measure this voltage, first power up the part and use the software to turn on the ILED. Then apply an external voltage to the OUT pin and keep raising it until the ILED turns off. That voltage is the overvoltage threshold.

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-01

0

INT


SHORTTHESEJUMPERS

SHORT THISJUMPER

SHORT ENTO H

POWERSUPPLY

FORCE A HIGHVOLTAGE AT

OUT PIN

LIGHTILED UP



SHORTVIC

TO 3.3V


VOLTMETER


VBAT VOLTAGE

AMMETER

AMMETERTO MEASURE

INPUT CURRENT

POWERSUPPLY


INT

Figure 10. Measuring Overvoltage Protection

AN-861

Rev. 0 | of 20

LX SWITCHING FREQUENCY

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-01

1

INT


SHORTTHESEJUMPERS

SHORT THISJUMPER

SHORT ENTO H

SCOPE



SHORTVIC

TO 3.3V


VOLTMETER


VBAT VOLTAGE

AMMETER

AMMETERTO MEASURE

INPUT CURRENT

POWERSUPPLY


INT

Figure 11. Measuring Switching Frequency

To see the LX switching waveform, power on the device and use the software to turn on the HPLEDs. Probe the test point right above Diode D1. Then, using the cursor function on the scope, measure the switching frequency.

Note that some switching waveforms contain ringing that should be included in the switching frequency measurement. The ringing is caused by the part going into the discontinuous mode of operation (the inductor current ripple dropping to 0) and is completely normal.

06

320-

012

CH1 2.00V M200ns A CH1 5.16V

1

T 50.20%

Δ: 3.84V@: 1.72V

Δ: 1.20MHz@: 1.20MHz

Figure 12. LX Pin, Discontinuous Conduction Mode

AN-861

Rev. 0 | of 20

OUT SOFT START RAMP

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-01

3

INT


SHORTTHESEJUMPERS

SHORT THISJUMPER

SHORT ENTO H

SCOPE

PRESS THESTROBE

BUTTON TOFLASH



SHORTVIC

TO 3.3V


VOLTMETER


VBAT VOLTAGE

AMMETER

AMMETERTO MEASURE

INPUT CURRENT

POWERSUPPLY


INT

Figure 13. Measuring OUT Soft Start Ramp

The ADP1653 contains a soft start feature at the OUT pin to reduce the output voltage ramp rate. This prevents a large inrush current to the chip, as well as accidental tripping of the overvoltage threshold. To measure the OUT soft start ramp rate, hook up a scope to the OUT pin.

Use the software to program the first flash setting to the part. Program the HPLED register to 0x09 or any other setting, as desired, and press the strobe button to flash the LEDs. Capture the output voltage waveform on the scope, and measure the amount of rise in the output voltage and the time it takes. Dividing the output voltage rise by the time yields the soft start ramp rate.

In the example shown in Figure 14, the soft start ramp rate is

ss

μ=μ

V/23.19183

V52.3

0632

0-01

4

CH1 1.00V M40.0µs A CH1 4.76V

1

T 50.00%

Δ: 3.52V@: 2.88V

Δ: 183µs@: –102µs

Figure 14. Typical Soft Start Ramp

AN-861

Rev. 0 | of 20

START-UP INRUSH CURRENT

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-01

5

INT

VOLTMETER


VBAT VOLTAGE


SHORTTHESEJUMPERS

SHORT THISJUMPER

SHORT ENTO H

SCOPE POWERSUPPLY


PRESS THESTROBE

BUTTON TOFLASH



SHORTVIC

TO 3.3V


INT

Figure 15. Measuring Inrush Current at Startup

When the ADP1653 first starts boosting, it may initially draw slightly more current than required, which is known as the start-up inrush current. To measure the inrush current, place a current probe on the positive power supply cable, use the software to program the HPLED register to the desired setting (press the strobe button if in the flash mode), and capture the input current waveform on the scope.

Figure 16 shows an example of the start-up inrush current, and the overshoot is the inrush current. How much overshoot there is depends on the external components, such as the input/output capacitors.

0632

0-01

6

CH1 10.0mV Ω M100µs A CH1 15.4mV

1

T 0.0s

CH1 MAX28.0mV

Figure 16. Typical Supply Inrush Current Waveform

AN-861

Rev. 0 | of 20

EFFICIENCY Torch Mode

LED efficiency is computed using the following equation:

INBAT

OUTLED

IVIV××

The user must first measure VLED, IOUT, VBAT, and IIN separately. VBAT and IIN are easily measured with a voltmeter and an ammeter. For IOUT, it is recommended that a high power current-sensing resistor of a small value be used, such as 0.1 Ω. Solder the leads of the resistor directly onto Jumper J3 without using any wires, because the wire resistance could be on the same order of magnitude as that of the resistor. Measure the voltage drop across the resistor and divide it by the resistance to compute the output current. Note that there is some loss in efficiency due to the current-sensing resistor. The amount of loss depends on the size of the resistor. For example, if R = 0.1 Ω and IOUT = 500 mA, then VLOSS = 0.05 V and PLOSS = 25 mW.

Under normal boost conditions, VLED ≈ 6.5 V; therefore, POUT = 3.25 W, and the efficiency loss due to the sense resistor is 0.77%. The user can add that loss back to the calculated efficiency to get the real efficiency.

When measuring VLED, the two terminals of the voltmeter must be connected to the OUT pin and the HPLED pin, respectively. This measures the voltage across the LEDs, and the efficiency computed from it is the LED efficiency. If the negative terminal of the voltmeter is connected to ground, then the voltage measured is the pure boosted output voltage, and the efficiency calculated is the boost efficiency. The LED efficiency is always lower than the boost efficiency, because there is approximately a 350 mV loss at the HPLED pin when the part is boosting.

In addition, when measuring the efficiency at different output currents and a fixed VBAT voltage, increasing the output current inevitably decreases the supply voltage that the part receives due to the internal resistance of the cables. As a result, the user must adjust the power supply so the voltage at the VBAT pin stays constant.

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-01

7

INT


SHORTTHESEJUMPERS

SHORT ENTO H

VOLTMETER

MEASURELED VOLTAGE



SHORTVIC

TO 3.3V


VOLTMETER

HIGHPOWER

CURRENTSENSING

RESISTOR

MEASURELED CURRENT

PRESS THESTROBE

BUTTON TOFLASH

VOLTMETER


VBAT VOLTAGE

AMMETER

AMMETERTO MEASURE

INPUT CURRENT

POWERSUPPLY


INT

Figure 17. Measuring Efficiency in Torch Mode

AN-861

Rev. 0 | of 20

Flash Mode

Efficiency measurement in the flash mode is not as straight-forward as in the torch mode because the boost only lasts less than a second. As a result, scopes must be used to capture the waveforms. Use a 4-channel scope to capture VBAT, IIN, VOUT, and IOUT, and use a separate scope to probe VHPLED. Subtracting VHPLED from VOUT gives VLED.

To measure IIN, use a current probe on the power supply cable. To measure IOUT, place a thick wire loop on Jumper J3 and use another current probe to measure the current.

Keep in mind that scopes do not have as much resolution as a voltmeter or ammeter, so the flash efficiency computed may have some error. It is advisable to use a calibrated electronic load to do regular probe calibration of the wire used in the measurement.

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-01

8

INT


SHORTTHESEJUMPERS

SHORT ENTO H

POWERSUPPLY




SHORTVIC

TO 3.3V


SCOPE

4-CHANNELSCOPE

PRESS THESTROBE

BUTTON TOFLASH

CURRENTPROBE

CURRENTPROBE

INT

Figure 18. Measuring Efficiency in Flash Mode

AN-861

Rev. 0 | of 20

CURRENT LIMIT

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-01

9

INT


CURRENTPROBE

CURRENTPROBE

SHORT ENTO H

POWERSUPPLY




SHORTVIC

TO 3.3V


4-CHANNELSCOPE

PRESS THESTROBE

BUTTON TOFLASH

SHORT THISJUMPER

INT

Figure 19. Measuring Current Limit

The purpose of the current limit is to restrict the amount of input current so the battery does not get overloaded. When the current limit is reached, both the input and LED currents stop increasing, even if the user tries to program a higher LED current setting.

To measure the current limit, place a thick wire loop on Jumper J1 and use a current probe to capture the inductor current waveform on the scope. Then, use the software to increase the LED current setting, until a point when the inductor current stops increasing. The peak of the inductor current is the current limit.

It may be useful, as well, to measure the LED current to know the maximum LED current that can be achieved with the particular external components.

Figure 20 shows the inductor current ripple when the current has NOT been reached, and Figure 21 shows when the current limit has been reached. In the figures, Channel 1 is input voltage, Channel 2 is inductor current ripple, and Channel 4 is output current.

0632

0-02

0

CH1 5.00V CH2 500mA ΩCH4 10.0mV Ω

M1.00µs A CH2 1.18A

2

4

1

T 50.60%

Δ: 3.60V@: 3.60VCH2 MAX1.43A

Figure 20. Inductor Current Waveform

0632

0-02

1

CH1 5.00V CH2 500mA ΩCH4 10.0mV Ω

M1.00µs A CH2 1.18A

2

4

1

T 50.60%

Δ: 3.60V@: 3.60VCH2 MAX1.9A

Figure 21. Inductor Current Waveform at Current Limit

AN-861

Rev. 0 | of 20

LINE REGULATION

GNDVBAT

ENSTR

SCLSDA

Tx

VIC

REV 0.4.1

GND

J7

J5

J4

J6

SETT

SETF

SETI

J8J1

J3

JP3GND

GND

R4R3

R5R6

R2

R1

ADP1653

L1

C1

D1

C2

C3

D2

D3J2

GNDVBAT

OUT

HPLEDD10

SHARP

GND

ANALOG DEVICES

MINIUSB

5V VBAT 1.8V 3.3V

VBAT

5VJP13 JP12

C19

U4

R25

R24R22

C14C11R50 C10

C51C8

C30

C31

U3

C5 D8C12

C13

C7C9 C18

R31

R30

U2C6

R64R63

R62

C17

C15 C16 R66

R65

C21R27

R26

U5C20

C50R21

USB_OK

STROBE

JP10 JP11 JP9

SCL/CTRL1H L H HL L

SDA/CTRL0 TxMASK

EN

H LJP6 R51

EN STR

SCL

SDA

GP2

GP1

GN

D INT GP2 GP1

D5

R19

D6

R20

D7

R23


VIC

0632

0-02

2

INT


SHORTTHESEJUMPERS

SHORT THISJUMPER

SHORT ENTO H

VBAT1

VBAT2SCOPE



SHORTVIC

TO 3.3V


PRESS THESTROBE

BUTTON TOFLASH

INT

Figure 22. Measuring Line Regulation

Line regulation measures how much the output voltage changes in response to a change in the input voltage. To test this, the setup shown in Figure 22 can be used with two high power Schottky diodes and a P-channel power MOSFET. Use a function generator to generate a square wave for the gate of the MOSFET. If VBAT1 < VBAT2, when the gate of the MOSFET is low, the top diode is reverse-biased, and VBAT = VBAT2. When the gate is high, the bottom diode is reverse-biased, and VBAT = VBAT1.

Figure 23 shows the line regulation when VBAT1 = 3.3 V and VBAT2 = 4.0 V. Because ADP1653 is a current-mode controller, it is insensitive to changes in the supply voltage, and the line regulation is very good. 06

320-

023

CH1 1.00V CH2 2.00V M100ms A CH1 3.68V

2

1

T 40.60%

CH1 = VBATCH2 = VOUT

Figure 23. Typical Line Regulation Plot

functional block diagram - analog devices

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