SEMTECH SC614 Technical data

1

POWER MANAGEMENT

SC614

Low Noise Backlight and Flash

Driver With Serial Interface

United States Patent No. 6,504,422

www.semtech.com

POWER MANAGEMENT

April 28, 2006

Features

 Four independent current sinks for main backlight, adjustable from 0.4mA to 32mA each  Dedicated MDIM pin for PWM dimming of main backlight  Three independent current sinks for sub-backlight or flash, adjustable from 0.4mA to 102mA each

 Configurable sub-backlight or flash sinks  Dedicated SDIM pin for PWM dimming of sub-

backlight

 Dedicated FL pin for flash control  Current accuracy to within ±1.5% down to 4.8mA  Current matching to within ±0.5% down to 4.8mA  Very high efficiency over 90% of battery life  Shutdown current 0.1μA (typ)  Three charge pump operating modes: 1x, 1.5x,

and 2x

 I2C serial interface  Soft-start/in-rush current limiting  1.33MHz and 250kHz programmable fixed

frequency options

 Short-circuit/thermal protection  Output open circuit protection  MLPQ-24 package (4mm x 4mm), fully WEEE and

RoHS compliant

 Cellular phone backlighting and flash  LCD modules  PDA backlighting and flash  RGB LED Driver

The SC614 is a high efficiency charge pump LED driver using Semtech’s proprietary mAhXLifeTM technology. Performance is optimized for use in Li-ion battery applications.

Each of 7 LED currents can be programmed via the I2C serial control bus. M1 through M4 are for LED backlighting of LCD main displays. S1/FL3 through S3/FL1 can be used for backlighting sub displays and/ or for driving flash LEDs. These three current sinks are configurable over the I

2

C interface for any combination

of pins for sub or flash use.

The charge pump automatically selects an operating mode based on the number of active loads, input voltage, and load currents required. Any combination of LED drivers can be enabled at one time, allowing the SC614 to power any combination of backlight and flash required by the application.

Two dedicated pins, MDIM and SDIM, are provided to allow PWM dimming of the main and sub-backlights and one dedicated pin, FL, allows direct control of the flash. All three pins can be utilized without having to use the I

2

C interface once the registers are set up.

The enable pin can be used to put the device in low-current shutdown mode drawing 0.1μA (typ), or a register can be written that sets the device in a sleep mode that reduces the current to 50μA (typ).

Description

D1 LED

C2

1u

434mA Max (500ms)

D2 LEDD3LEDD4LED

D5 LED

32mA Max

306mA Max .

C1

2u2

C3 1u C4 1u

VIN

11

VIN

17

EN

2

SDA

7

SCL

8

ASEL

5

SDIM

3

MDI M

4

FL

6

VOUT

9

VOUT

16

M1

1

M2

24

M3

23

M4

22

S1/FL3

20

S2/FL2

19

S3/FL1

18

GND

12

GND

21

TPAD

C1+10C1-

13

C2+15C2-

14

U1

SC614

EN

SDA

SCL

SDIM

FL

MDIM

328mA Max Continuous

VBAT

R1

Pull-upR2Pull-up

VLOGIC

Note: R1 and R2 pull-up resistors are a requirement of the I2C specific ation

MA IN BA CKL IGHT FLASH

Typical Application Circuit

Applications

查询SC614EVB供应商

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

www.semtech.com

2

Absolute Maximum Ratings

Electrical Characteristics

Unless specified, TA = 25°C for Typ, -40°C to 85°C for Min and Max, VIN = 3.2V to 4.2V, CIN = 2.2μF, C

OUT

= C

PUMP

= 1μF (ESR = 0.03Ω).

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CCA_DEL

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V

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V,ylnosniphsalF

NI

I,V7.3=

TES

Am201=1±

Exceeding the specifications below may result in permanent damage to the device or device malfunction. Operation outside of the parameters specified in the Electrical Characteristics section is not implied. Exposure to Absolute Maximum rated conditions for extended periods of time may affect device reliability.

Notes:

(1) Calculated from package in still air, mounted to a 3” x 4.5”, 4-layer FR4 PCB with thermal vias under the exposed pad per JESD51 standards. (2) Tested according to JEDEC standard JESD22-A114-B.

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

www.semtech.com

3

POWER MANAGEMENT

Electrical Characteristics (Cont.)

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PMUP

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V=

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HI

V

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LI

V

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V

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LF

elcycytud%0501zHk

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

www.semtech.com

4

Electrical Characteristics (Cont.)

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V

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ecnaticapaCniPO/IC

NI

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noitidnoCtratS

)2(

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noitidnoCtratS

)2(

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)2(

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tiucriCtrohStuptuO

timiLtnerruC

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erutarepmeTrevO

)4(

T

PTO

)C°01=siseretsyh(dlohserhtgnisiR061C°

egatloVrevOtuptuOV

PVO

7.5V

Notes:

(1) LED matching applies to current sinks set to the same current only. Matching is calculated as follows:

(

)

()

%100

II

I

MINMAX

LEDLED

•

+

−

±=

−

(2) Guaranteed by design. (3) The total quiescent current in Sleep Mode will increase when serial bus activity occurs, and with the clock frequency of that bus activity. (4) When the junction temperature exceeds the Over Temperature (OT) threshold, the device will enter Sleep Mode with the contents of all registers retained. The device will exit Sleep Mode and re-commence normal operation as soon as the junction temperature drops by more than the OT hysteresis.

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

www.semtech.com

5

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Block Diagram

mAhXLife

TM

Fractional Charge Pump

(1x, 1.5x, 2x)

Oscillator

Digital

Interface

and

Logic

Control

Current

Setting

DAC

VIN

EN

SDA

SCL

VOUT

M1

C1+

C1-

C2+ C2-

FL

Control

Override

MDIM

SDIM

VIN

VOUT

ASEL

Pull high or low to set slave address

11

17

2

7

8

4

3

5

6

10 13 15 14

9

16

22

23

24

1

18

12

21

M2

M3

M4

S1/FL3

S2/FL2

S3/FL1

GND

20

19

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

www.semtech.com

6

Pin Configuration

eciveDegakcaP

TRTLM416CS

)1(

42-QPLM

)2(

BD416CS

)3(

draoBnoitartsnomeD

BVE416CS

)4(

draoBnoitaulavE

Notes:

(1) Lead free product. This product is fully WEEE and RoHS compliant. (2) Only available in tape and reel packaging. A reel contains 3000 devices. (3) The demonstration board showcases the most common uses for this part, running at maximum current settings. (4) The evaluation board is user-configurable and allows the user to communicate with the part using a graphical user interface on a personal computer with a USB connection. Contact factory for availability.

Marking Information

614

yyww

yy = two-digit year of manufacture

ww = two-digit week of manufacture

xxxxx = lot number

Top Mark

xxxxx xxxxx

MLP24: 4X4 24 LEAD

TOP VIEW

1

2

3

4

6

5

7 8 9 10 11 12

24 23 22 21 20 19

18

17

16

15

13

14

T

M1

EN

SDIM

MDIM

ASEL

FL

S3/FL1

VIN

VOUT

C2+

C2-

C1-

M2

M3

M4

GND

S1/FL3

S2/FL2

SDA

SCL

VOUT

C1+

VIN

GND

Ordering Information

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SC614

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Pin Descriptions

#niPemaNniPnoitcnuFniP

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7ADSI

2

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8LCSI

2

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9TUOV.61nipottcennoC.tuptuopmupegrahC

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isop1CroticapactekcuB

11NIV.71nipottcennoC.tupniegatlovyrettaB

21DNG.enalpdnuorgotyltceridtcennoC.nipdnuorG

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41-2C.noitcennocevitagen2CroticapactekcuB

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knistnerruC

323M .desutonfidetcennocnuevaeL.3DELthgilkcabniamroftupniknistnerruC

422M .desutonfidetcennocnu

evaeL.2DELthgilkcabniamroftupniknistnerruC

-LAMREHT DAP

detcennoctoN.saivelpitlumgnisuenalpdnuorgottcenno

C.sesoprupgniknistaehrofdaP

.yllanretni

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

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8

Register Map

Note: all registers are readable and writable.

Definition Of Terms:

0: Leave this bit as a 0.

xEN: On/off control for individual current sinks. Set to 1 to enable, clear to 0 to disable.

FLMODE: Flash Mode control bit. Set to 1 for Flash mode, clear to 0 for normal mode.

SLEEP: Sleep Mode control bit. Set to 1 to put into low current mode (Bandgap, UVLO monitor and interface

monitoring stay on, all other circuitry shut down),

clear to 0 for normal mode.

SWRES: Software Reset bit. Set to 1 to reset all registers (SWRES clears automatically and does not require an additional I

2

C write).

FSEL: Frequency Select bit. Allows the choice between two different switching frequencies, set to 1 for 1.33MHz,

clear to 0 for 250kHz.

sserddA7D6D5D4D3D2D1D0DteseR

eulaV

noitpircseD

00x0

0NE1LF/3SNE2LF/2SNE3LF/1SNE4MNE3MNE2MNE1M00x0ffO/nODEL

lortnoc

10x0

0 Am23=05x0,FFO=00x0,tib/Am4.0,gnittestnerructib-7 00x0tnerruc1M

lortnoc

20x0

0 Am23=05x0,FFO=00x0,tib/Am4.0,gnittestnerructib-7 00x0tnerruc2M

lortnoc

30x0

0 Am23=05x0,FFO=00x0,tib/Am4.0,gnittestnerructib-7 00x0tnerruc3M

lortnoc

40x0

0 Am23=05x0,FFO=00x0,tib/Am4.0,gnittestnerructib-7 00x0tnerruc4M

lortnoc

50x0

Am201=FFx0,FFO=00x0,tib/Am4.0,gnittestnerructib-8 00x03LF/1S

lortnoctnerruc

60x0

Am201=FFx0,FFO=00x0,tib/Am4.0,gnittestnerructib-8 00x02LF/2S

lortnoctnerruc

70x0

Am201=FFx0,FFO=00x0,tib/Am4.0,gnittestnerructib-8 00x01LF/3S

lortnoctnerruc

80x0

0EDOMLFPEELSSERWSLESF1LF0LF002x0lortnoC

retsigeR

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Register Map (Cont.)

FL1,0: Control Override bits for S1/FL3, S2/FL2 and S3/FL1. Enable control is transferred to the FL pin (assuming the LEDs are first enabled) based on the following table:

1LF0LFsutatSlortnoCniPLF

00 .delbasidnipLF-stibretsigerybdeniatniamlortnoC

01 .nipLFehtybdellortnocelbane1LF/3S

10 .nipLFehtybdellortnocselbane2LF/2S,1LF/3S

11 .nipLFehtybdellortnocselbane3LF/1S,2LF/2S,1LF/3S

SC614 Slave Address

Following a start condition, the master must output the address of the slave it is accessing. The most significant six bits of the slave address are the device type identifier (ID). For the SC614 this is fixed at 111000[ASEL]. The next significant bit addresses a particular device. A system can have up to two SC614 devices on the same bus. The two addresses are defined by the state of the ASEL input (see Table below).

REIFITNEDIEPYTECIVEDSSERDDAECIVEDW/R

111000

0=DNGotLESAniP

1=NIVotLESAniP

X

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State Diagrams

When the SC614 is first enabled, it starts up in Sleep Mode, with the registers at their reset values and the charge pump off. The bandgap reference will be operating, the input voltage will be monitored for UVLO and the serial interface will be monitored for any activity. This is the lowest power state for the device where it can be communicated with. In order to activate the charge pump it is necessary to clear the Sleep bit to 0 to enter Run Mode. When in Run Mode the charge pump is activated in 1x mode with VOUT = 1.5V, and all of the optional functions of the device may be accessed.

Shutdown

Sleep Mode

(

SLEEP

=

1

)

Power Off

VIN high ,

EN

low

EN

=

High

VIN , EN high

Run Mode

(

SLEEP

= 0

)

SLEEP

=

0

Lowest Power State.

All internal

functions powered down

Bandgap up,

UVLO and serial

interface monitoring active only

Bandgap up, UVLO and serial

interface monitoring active, charge pump running with

VOUT = 1.5V

Start-Up

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State Diagrams (Cont.)

Power Management

Sleep Mode

(Register

contents stored)

Shutdown

(EN low)

Sleep Mode

(Register

contents reset)

SLEEP = 1 from any Run Mode SWRST = 1 from any Run Mode EN low from any mode

SLEEP = 0

Return to

previous Mode

SLEEP = 0

Run Mode

There are three options for powering down the SC614 (other than writing 0x00 to each Current Control Register or the LED On/Off Control Register):

Sleep Mode (SLEEP = 1)

Setting this bit to 1 at any time will power down the charge pump. The register contents will be stored, the bandgap reference will remain active, and UVLO and serial interface monitoring will continue. Clearing this bit will resume operation as before.

Sleep Mode from Reset (SWRES = 1)

Setting SWRES to 1 will reset all registers (clearing the SWRES bit), causing the part to enter Sleep Mode but with all registers at their reset values (0x00 for registers 0x00 through 0x07, 0x20 for Control Register 0x08 (SLEEP =

1). Upon clearing the SLEEP bit, the SC614 will enter run mode and will require writing to the registers to commence driving LEDs.

Shutdown (EN low)

All internal functions are powered down. Pulling EN high will enter Sleep Mode with all registers reset.

Device Operation With All LEDs Disabled

If the SC614 is driving LEDs and then all LEDs are disabled, the device reverts to 1x mode with a nominal output voltage of 3V. This decreases the response time when the LEDs are enabled once more. Quiescent current in this mode will be 700μA (nom).

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General Operation

The SC614 contains a fractional charge pump, mode selection circuitry, serial I/O logic, serial data registers and current regulation circuitry for 7 LED outputs. All are depicted in the Block Diagram on page 5.

The fractional charge pump multiplies the input voltage by 1, 1.5 or 2 times the input voltage. The charge pump switches at a fixed frequency that is bit selectable to

1.33MHz or 250kHz. The default frequency is 250kHz. The charge pump does not switch during 1x mode, saving power and improving efficiency.

The mode selection circuitry automatically selects the mode as 1x, 1.5x or 2x based on circuit conditions such as LED voltage, input voltage and load current. 1x is the most efficient mode, followed by 1.5x and 2x modes. At lower input voltages a stronger mode may be needed to maintain regulation. If so, the mode will change first to

1.5x and then later to 2x. 2x mode usually operates for a much shorter run time compared to 1x mode, and 2x mode maintains the output until the battery is discharged to 3V or less. The LED requiring the highest voltage drop will determine the output voltage needed to drive all outputs with sufficient anode voltage. Comparing all cathodes and regulating VOUT for the LED with the lowest cathode voltage ensures sufficient bias for all LEDs.

The LED outputs are controlled through the serial data registers, found in the Register Map on page 8. LED on/ off functions are independently controlled, so that any combination of LEDs may be switched on.

Seven (7) current regulating circuits sink currents from the LEDs as set by the Current Control registers. For LCD backlighting applications current matching is crucial, and LEDs with matched forward voltage will produce the best possible matched currents. The SC614 is capable of dealing with V

F

mis-matches up to 0.5V. For best matching performance, however, it is recommended that the LED to LED difference, ΔVF, be under 250mV.

Designing for Lowest Possible Battery Current

The battery current and efficiency of the SC614 are mostly dependent on the charge pump mode of operation. To get the best performance from the SC614 it is better to use LEDs with consistantly lower VF. Lower VF will keep the charge pump in 1x mode longer and will use less battery current, extending the run time of the battery.

Mode Transition Threshold Voltage and Hysteresis

Mode transition threshold voltage refers to the input voltage at the point when the charge pump changes from a weaker mode (lower numerically) to a stronger mode (higher numerically). V

TRANS1X

is the transition from 1x to

1.5x mode, and V

TRANS1.5X

is the transition from 1.5x to 2x

mode.

Mode transition voltages V

TRANS1X

and V

TRANS1.5X

can be

estimated by the following equations:

V

TRANS1X

= VF + V

ILED

+ I

OUT

1.0

V

TRANS1.5X

= (VF + V

ILED

+ I

OUT

5.5) / 1.5

where VF is the highest forward voltage of the operating LEDs, V

ILED

is the current sink voltage for that LED (typically

V

ILED

=150mV) and I

OUT

is the sum of all operating LED

currents.

The mode transition circuitry has hysteresis built in to prevent the device from toggling between modes when the input voltage is right at the threshold of mode change. There is 100mV of hysteresis between 1.5x and 1x modes and 200mV of hysteresis between 2x and 1.5x modes.

Efficiency

Power efficiency can be estimated for any particular battery voltage as follows:

η = [V

OUTIOUT

/ VIN(I

OUT

Mode+IQ)] 100 %

where:

V

OUT

= VF+ V

ILED

(defined in the above section).

and,

IQ = 1mA in 1x mode, 1.4mA in 1.5x mode and 1.8mA in 2x mode (250kHz).

LED Current Accuracy

The LED current is set by the Current Control registers 0x01 through 0x07. The guaranteed accuracy of any current sink is +/-8% at a current setting of 20mA, with the typical accuracy much higher at +/-1.5%. For example, if the Current Control registers are configured such that each LED current will be 20mA (0x32 written to register 0x01 through 0x07), the actual LED currents

Applications Information

POWER MANAGEMENT

SC614

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13

POWER MANAGEMENT

would be between 18.4mA and 21.6mA (+/-8%). All 7 outputs meet this requirement over the industrial temperature range. To calculate the accuracy based upon the actual measured LED current, I

LED_ACC

, use the

following formula:

(

)

%100

I

II

I

)SET(LED

)SET(LED)Measured(LED

ACC_LED

•

−

±=

Current Matching

The current matching percentage is a figure that represents how closely matched LEDs are that are set to the same current. For any particular LED within a group of LEDs set to the same current, the matching is the ΔI for that LED from the average of the minimum and maximum value of the group (i.e. the center of the measured current range) expressed as a percentage of that average.

Current matching is calculated as follows:

%100

2

II

I

or%100

2

II

I

MINMAX

MIN

MINMAX

MAX

LED_LED

•

⎟

⎠

⎞

⎜

⎝

⎛

⎟ ⎠

⎞

⎜ ⎝

⎛

+

•

⎟

⎠

⎞

⎜

⎝

⎛

⎟ ⎠

⎞

⎜ ⎝

⎛

+

=

Which can be reduced to:

(

)

()

%100

II

I

MINMAX

LED_LED

•

+

−

±=

Protection Circuitry

The SC614 also provides protection circuitry that prevents the device from operating in an unspecified state. These include Output Over-Voltage Protection (OVP), Over-Temperature Protection (OTP), Over-Current Protection (OCP) and Short-Circuit Protection (SCP).

Output Over-Voltage Protection

Output over-voltage protection is included to prevent the SC614 from generating an output voltage that could damage other devices connected to it such as load LEDs any bypass capacitors. When the output voltage exceeds

5.7V, the OVP circuitry disables the charge pump until the output voltage decreases to an acceptable level. Usually the only reason for the output voltage to trip OVP is if one of the LEDs goes open. If this happens the SC614 will raise the output voltage to attempt to bring

Applications Information (Cont.)

that LED current back into regulation. When the OVP trip point is reached, the charge pump will be turned off. Any current sinks that measure close to ground will be turned off in an attempt to isolate the faulty LED. Once the output voltage drops enough the charge pump will resume operation.

Over-Temperature Protection

The over-temperature protection circuitry helps to prevent the device from overheating and experiencing a catastrophic failure. When the junction temperature exceeds 160°C the output is disabled and the device enters sleep mode. All register settings are retained. The junction temperature must drop by more than the hysteresis of 10°C before the part exits sleep mode and re-commences normal operation.

Over-Current and Short Circuit Protection

Adaptive current limit circuitry is provided to protect the device from various levels of shorts from resistive to full shorts as well as to limit in-rush current at start-up and during mode transitions. The current limit levels adjust to the total output current set for the LEDs and thus will be higher when very high levels of currents are programmed, such as for flash operation. The current limit levels are set to ensure that the device will not current limit under normal operation. When an output short circuit occurs, the device folds back the current limit level to a nominal 300mA. If sustained current limit occurs the device may shut down due to internal heating triggering the OTP circuitry.

Capacitor Selection

The SC614 is designed to use low-ESR ceramic capacitors for all four external capacitors: input, output and charge pump bucket capacitors. Ideal performance is achieved when the bucket capacitors (C3 and C4 in the application circuit) are exactly equal.

Note: It is recommended that X5R or X7R capacitors are used for best performance.

Thermal Resistance and Heat Management

The SC614 is packaged in a thermally efficient MLPQ24 package that has a thermal pad to remove the heat from the part. It is intended to be connected using multiple vias to the ground plane, and the thermal resistance rating of 40°C/W reflects this. A good layout will enable the part to operate at maximum output current ratings without tripping the OTP circuitry.

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

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14

Applications Information (Cont.)

Layout Guidelines

The following layout is suggested (shown as three-layer (top, bottom and ground layer) only for clarity). C1 is the input capacitor which should be placed close to pin 17. C2 is the output capacitor which should be placed close to pin 16. The capacitors C3 and C4 are the bucket capacitors which can carry up to the full load current of 434mA pulsed for one half clock cycle (at either 250kHz or 1.33MHz depending upon selected operating frequency). Multiple vias should be used whenever it is necessary to change layers on nets connecting to CIN, VOUT, C1+, C1-, C2+ and C2-. As mentioned before, the thermal pad should connect to ground using multiple vias, with 4 vias recommended.

Top Copper and Top SilkscreenLayout Guidelines Schematic

C2

1u

C1

2u2

C3 1u C4 1u

VIN

11

VIN

17

EN

2

SDA

7

SCL

8

ASEL

5

SDIM

3

MDI M

4

FL

6

VOUT

9

VOUT

16

M1

1

M2

24

M3

23

M4

22

S1/FL3

20

S2/FL2

19

S3/FL1

18

GND

12

GND

21

TPAD

25

C1+10C1-

13

C2+15C2-

14

U1

SC614

VBAT

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

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15

POWER MANAGEMENT

Bottom Copper Ground Layer

Applications Information (Cont.)

POWER MANAGEMENT

SC614

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16

Application Examples

Main Backlight Plus Flash

D1 LED

C2

1u

434mA Max (500ms )

D2 LEDD3LEDD4LED

D5 LED

32mA Max

306mA Max.

C1

2u2

C3 1u C4 1u

VIN

11

VIN

17

EN

2

SDA

7

SCL

8

ASEL

5

SDIM

3

MDI M

4

FL

6

VOUT

9

VOUT

16

M1

1

M2

24

M3

23

M4

22

S1/FL3

20

S2/FL2

19

S3/FL1

18

GND

12

GND

21

TPAD

C1+10C1-

13

C2+15C2-

14

U1

SC614

EN

SDA

SCL

SDIM

FL

MDIM

328mA Max C ontinuous

VBAT

R1

Pull-upR2Pull-up

VLOGIC

Note: R1 and R2 pull-up resistors are a requirement of the I2C spec ifica tion

MA IN BACKLIGHT FLASH

Features:

• Up to 4 LED main backlight with up to 32mA per LED

• PWM dimming of backlight using MDIM pin

• Up to 306mA flash capability controlled by FL pin

Register Settings (20mA backlight currents and 300mA flash current used as an example):

0x00: set to 0x7F to enable all 7 current sinks for use 0x01 through 0x04: set to 0x32 for 20mA per current sink 0x05 through 0x07: set to 0xFA for 100mA per current sink, 300mA total 0x08: set to 0x46 for Flash Mode enabled, 250kHz charge pump frequency, FL pin controls S1/FL3, S2/FL2 and S3/FL1

POWER MANAGEMENT

SC614

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17

POWER MANAGEMENT

Application Examples (Cont.)

Main Backlight Plus Sub-Backlight

D1 LED

C2

1u

434mA Max (500ms )

D2 LEDD3LEDD4LED

D5 LED

32mA Max

C1

2u2

C3 1u C4 1u

VIN

11

VIN

17

EN

2

SDA

7

SCL

8

ASEL

5

SDIM

3

MDI M

4

FL

6

VOUT

9

VOUT

16

M1

1

M2

24

M3

23

M4

22

S1/FL3

20

S2/FL2

19

S3/FL1

18

GND

12

GND

21

TPAD

C1+10C1-

13

C2+15C2-

14

U1

SC614

EN

SCL

SDA

FL

SDIM

MDIM

VBAT

R1

Pull-upR2Pull-up

VLOGIC

Note: R1 and R2 pull-up resistor s are a requirement of the I2C spec ific ation

SUB BACKL IGHTMAI N BACKLIGHT

102mA Max

D6 LEDD7LED

328mA Max Cont inuous

Features:

• Up to 4 LED main backlight with up to 32mA per LED

• PWM dimming of main backlight using MDIM pin

• Up to 3 LED sub-backlight with up to 32mA per LED

• PWM dimming of sub-backlight using SDIM pin

Register Settings (20mA backlight currents used as an example):

0x00: set to 0x7F to enable all 7 current sinks for use (or as needed if less) 0x01 through 0x07: set to 0x32 for 20mA per current sink 0x08: set to 0x00 for Flash Mode disabled (FL pin inactive) and 250kHz charge pump frequency

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

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18

Application Examples (Cont.)

Main Backlight Plus Sub-Backlight Plus Flash

D1 LED

C2

1u

434mA Max (500m s)

D2 LEDD3LEDD4LED

D5 LED

102mA Max

C1

2u2

C3 1u C4 1u

VIN

11

VIN

17

EN

2

SDA

7

SCL

8

ASEL

5

SDI M

3

MDI M

4

FL

6

VOUT

9

VOUT

16

M1

1

M2

24

M3

23

M4

22

S1/FL3

20

S2/FL2

19

S3/FL1

18

GND

12

GND

21

TPAD

C1+10C1-

13

C2+15C2-

14

U1

SC614

SDA

EN

SDIM

SCL

FL

MDIM

VBAT

R1

Pull-up

VLOGIC

R2

Pull-up

Note: R1 and R2 pull-up resistors are a requirement of the I2C spe cif icatio n

MA IN BACKLI GHT SUB BACKLIG HT

102mA Max

D6 LED

D7 LED

R3

BalanceR4Balanc e

FLASH

328mA Max Cont inuous

Features:

• Up to 4 LED main backlight with up to 32mA per LED

• PWM dimming of main backlight using MDIM pin

• Up to 2 LED sub-backlight with up to 32mA per LED using resistor current balancing

• PWM dimming of sub-backlight using SDIM pin

• Up to 204mA flash capability controlled by FL pin

Register Settings (20mA backlight currents and 200mA flash current used as an example):

0x00: set to 0x7F to enable all 7 current sinks for use 0x01 through 0x04: set to 0x32 for 20mA per current sink 0x05: set to 0x64 for 40mA for this current sink (20mA per LED) 0x06 and 0x07: set to 0xFA for 100mA per current sink, 200mA total 0x08: set to 0x44 for Flash Mode enabled, 250kHz charge pump frequency, FL pin controls S2/FL2 and S3/FL1

POWER MANAGEMENT

SC614

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19

POWER MANAGEMENT

Application Examples (Cont.)

Main Backlight Plus RGB Indicator

D1 LED

C2

1u

D2 LEDD3LEDD4LED

D5

C1

2u2

C3 1u C4 1u

VIN

11

VIN

17

EN

2

SDA

7

SCL

8

ASEL

5

SDIM

3

MDI M

4

FL

6

VOUT

9

VOUT

16

M1

1

M2

24

M3

23

M4

22

S1/FL3

20

S2/FL2

19

S3/FL1

18

GND

12

GND

21

TPAD

C1+10C1-

13

C2+15C2-

14

U1

SC614

SDA

EN

SDIM

SCL

FL

MDIM

VBAT

R1

Pull-up

VLOGIC

R2

Pull-up

Note: R1 and R2 pull-up resis tors are a requirement of the I2C specif ication

MAIN BACKLIGHT RGB INDICATOR

RGB_LED

102mA Max

328mA Max Cont inuous

102mA Max

434mA Max (500ms )

Features:

• Up to 4 LED main backlight with up to 32mA per LED

• PWM dimming of backlight using MDIM pin

• 3 current sinks for RGB with up to 32mA per LED

• Dimming and color rotation of RGB over I

2

C interface

Register Settings (20mA backlight currents and as required on the fly RGB current used as an example):

0x00: set to 0x7F to enable all 7 current sinks for use 0x01 through 0x04: set to 0x32 for 20mA per current sink 0x05 through 0x07: set to as required on the fly for each color 0x08: set to 0x00 for Flash Mode disabled (FL pin inactive) and 250kHz charge pump frequency

POWER MANAGEMENT

SC614

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20

Using the I2C Serial Port

The I2C General Specification

The SC614 is a read-write slave-mode I

2

C device and complies with the Philips I2C standard Version 2.1 dated

January 2000. The SC614 has nine user-accessible internal 8-bit registers. The I

2

C interface has been designed for program flexibility, in that once the slave address has been sent to the SC614 enabling it to be a slave transmitter/receiver any register can be written or, read from independently of each other. While there is no auto increment/decrement capability in the SC614 I

2

C logic, a tight software loop can be designed to randomly access the next register independent of which register you begin accessing. The start and stop commands frame the datapacket and the repeat start condition is allowed if necessary.

SC614 Limitations to the I2C specifications

Seven bit addressing is used and ten bit addressing is not allowed. Any general call address will be ignored by the SC614. The SC614 is not CBUS compatible. Finally, the SC614 can operate in standard mode (100kbit/s) or fast mode (400kbit/s).

Supported Formats

Direct Format - Write: The simplest format for an I2C write is the direct format write. After the master sends a start

condition, the slave address is sent followed by an eighth bit indicating a write. The SC614 then acknowledges that it is being addressed, and the master responds with an 8-bit data byte consisting of the target register address. The slave acknowledges and the master sends the appropriate 8-bit data byte. Once again the slave acknowledges and the master terminates the transfer with a stop condition.

S sserddAevalS WA sserddAretsigeRAataDAP

S: Start Condition Slave Address: 7 bit W: Write = 0 Register Address: 8 bit A: Acknowledge (SDA low) Data: 8 bit P: Stop Condition

Shaded represents transmission from master to slave and unshaded represents transmission from slave to master.

Combined Format (Read/Write): After a start condition, the slave address is sent followed by an eighth bit indicating a write. The SC614 then acknowledges that it is being addressed, and the master responds with an 8 bit data byte consisting of the target register address. The slave acknowledges once more and the master sends the repeated start condition. Once again, the slave address is sent, followed by an eighth bit indicating a read or write. The slave responds with an acknowledge. If the command was a write, the master sends the appropriate 8-bit data byte. Once again the slave acknowledges and the master terminates the transfer with a stop condition. If the command was a read, the slave sends the appropriate 8-bit data byte, to which the master sends a not acknowledge and then terminates the transfer with a stop condition.

S sserddAevalS WA sserddAretsigeRArS sserddAevalS W/RA ataD

)1(

N/A

)1(

P

S: Start Condition N: Not Acknowledge(SDA high)

(1)

W: Write = 0 P: Stop Condition A: Acknowledge (SDA low) Slave Address: 7 bit Sr: Repeated Start Condition Register Address: 8 bit R: Read = 1 Data: 8 bit

Shaded represents transmission from master to slave and unshaded represents transmission from slave to master. (1) Not shaded because transfer direction depends upon R/W bit.

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

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21

POWER MANAGEMENT

Stop Separated Reads: A further form of read is available which is, in effect, an extension of the combined format read. This format allows a master to set up the register address pointer for a read, and return to that slave some time later to read the data. After a start condition, the slave address is sent, followed by a write. The SC614 then acknowledges that it is being addressed, and the master responds with the 8-bit target register address. The master then sends a stop or repeated start condition, and may address another slave. Some time later the master sends a start or repeated start condition, and a valid slave address is sent, followed by a read. The SC614 then acknowledges and returns the data at the register address location that had previously been set up.

S sserddAevalS WA sserddAretsigeRAP

retsaM(

sesserddA

rehtO

)sevalS

rS/S sserddAevalS RA ataD N P

S: Start Condition Slave Address: 7 bit W: Write = 0 Register Address: 8 bit A: Acknowledge (SDA low) Data: 8 bit P: Stop Condition Sr: Repeated Start R: Read = 0 Shaded represents transmission from master to slave and unshaded represents transmission from slave to master.

Using the I2C Serial Port (Cont.)

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

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22

Typical Characteristics

30

40

50

60

70

80

90

100

3.0 3.2 3.4 3.6 3.8 4.0 4.2

V

BAT

(V)

I

BAT

(mA)

LED 5-7 = 20mA

LED VF= 3.276V

Battery Current (Sub-only)

0

50

100

150

200

250

3.0 3.2 3.4 3.6 3.8 4.0 4.2

LED 1-7 = 20mA

LED VF= 3.340V

V

BAT

(V)

I

BAT

(mA)

Battery Current (Main and Sub)

30

40

50

60

70

80

90

100

3.0 3.2 3 .4 3.6 3 .8 4.0 4 .2

Conversion Efficiency

Utilized Power Efficiency

% Efficiency

V

BAT

(V)

LED 5-7 = 20mA

LED VF= 3.276V

Power Efﬁ ciency (Sub-only)

30

40

50

60

70

80

90

100

3.0 3.2 3.4 3.6 3.8 4.0 4.2

Conversion Efficiency

Utilized Power Efficiency

V

BAT

(V)

LED 1-7 = 20mA

LED VF= 3.340V

% Efficiency

Power Efﬁ ciency (Main and Sub)

-3 .5

-2 .5

-1 .5

-0 .5

0.5

1.5

2.5

3.5

3.03.23.43.63.84.04.2

LED Matc

h

ing

(

%

)

V

BAT

(V)

LED 1-7 = 20mA

Typical LED Matching (Main and Sub)

-6 .0

-4 .0

-2 .0

0.0

2.0

4.0

6.0

3.0 3 .2 3.4 3.6 3.8 4 .0 4.2

Max

Min

LED Accuracy %

V

BAT

(V)

Typical LED Accuracy (Main and Sub)

POWER MANAGEMENT

SC614

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23

POWER MANAGEMENT

Typical Characteristics (Cont.)

300

400

500

600

700

800

900

3.0 3.2 3.4 3.6 3.8 4.0 4.2

V

BAT

(V)

I

BAT

(mA)

LED 1-4 = 20mA

LED 5-7 = 100mA

LED V

F

= 3.388V

Battery Current (Main and Flash)

40

60

80

100

120

140

3.0 3.2 3.4 3.6 3.8 4.0 4.2

I

BAT

(mA)

V

BAT

(V)

LED 1-4 = 20mA

LED V

F

= 3.23V

Battery Current (Main only)

30

40

50

60

70

80

90

100

3.03.23.43.63.84.04.2

Utilized Power Efficiency

Conversion Efficiency

LED 1-4 = 20mA

LED 5-7 = 100mA

LED V

F

= 3.388V

% Efficiency

V

BAT

(V)

Power Efﬁ ciency (Main and Flash)

30

40

50

60

70

80

90

100

3.0 3.2 3.4 3.6 3.8 4.0 4.2

Utilized Power Efficiency

Conversion Efficiency

LED 1-4 = 20mA

LED V

F

= 3.23V

% E ff ici enc y

V

BAT

(V)

Power Efﬁ ciency (Main only)

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

www.semtech.com

24

E1

e

bxN

D/2

1

2

N

E1

.100

.106 .110 2.55

2.70

2.80

PIN 1

INDICATOR

4.153.85

4.00 4.153.85.157

.151 .163

aaa C

A

C

(LASER MARK)

D

E

B

A1

A

A2

SEATING

PLANE

LxN

E/2

bbb C A B

D1

INCHES

.020 BSC

b

.007

bbb

aaa

N

D1

E

L

e

D

.011

.100

DIM

A1 A2

A

MIN

.000

-

.031

0.30

0.18.012

0.25

.010

0.50

2.80

0.30

2.55

.004

24

.016

.157 .106

.020

.110

0.10

24

0.40

4.00

2.70

0.50 BSC

MILLIMETERS

MAX

0.05

-

1.00

DIMENSIONS

MIN

0.00

-

NOM

(.008)

.035 .001

MAX

.002

-

.040

NOM

0.80

0.02

(0.20)

0.90

CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES).

COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS.

NOTES:

2.

1.

Outline Drawing MLPQ-24 4 x 4

POWER MANAGEMENT

SC614

United States Patent No. 6,504,422

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25

POWER MANAGEMENT

THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR

NOTES:

1.

DIM

X Y

H K P

C G

MILLIMETERSINCHES

(3.95)

.010 .033

.122

.021

.106

(.155)

0.25

0.85

2.70

0.50

2.70

3.10

DIMENSIONS

COMPANY'S MANUFACTURING GUIDELINES ARE MET.

4.80.189Z

K

G

Z

H

(C)

X

P

Land Pattern MLPQ-24 4 x 4

Contact Information

Semtech Corporation

Power Management Products Division

200 Flynn Road, Camarillo, CA 93012

Phone: (805) 498-2111 FAX (805)498-3804

Contact Information

Visit us at: www.semtech.com

SEMTECH SC614 Technical data

Specifications and Main Features

Frequently Asked Questions

User Manual