Diodes AL3158 User Manual

AL3158

HIGH EFFICIENCY 1x/2x CHARGE PUMP

FOR WHITE LED APPLICATIONS

Description

Pin Assignments

The AL3158 is a low noise, constant frequency charge pump
DC/DC converter that uses a Dual mode load switch (1x), and (2x)
conversion for white LED applications. The AL3158 is capable of
driving three groups of three LED channels at 20mA from a 2.7V to

5.5V input. The current sinks may be operated using three simple
PWM dimming inputs individually or in parallel for driving higher­current LEDs. Low external part counts (one 1µF flying capacitor
and two 2.2µF capacitors at V
suited for small, battery-powered applications.

and V

IN

) make this part ideally

OUT

AL3158 PWM dimming inputs are used to enable, disable device
and dimming LED current with a fixed default current settings at
20mA or other factory programming options available.

Each output of the AL3158 is equipped with built-in protection for
V

short circuit and auto-disable for LED short conditions. Built-in

OUT

soft-start circuitry prevents excessive inrush current during start-up
and mode switching. A low-current shutdown feature disconnects
the load from V

to reduce quiescent current less than 1µA.

IN

The AL3158 is available in a lead-free, space-saving, thermally
enhanced 20-pin 3 x 3mm QFN package.

Features

NEW PRODUCT

• VIN Range: 2.7V to 5.5V

• Up to 93% Max Power Efficiency

• 1% Current Matching Accuracy Between Channels

• Three simple PWM dimming for RGB or WLED

• Low transition threshold voltage typical 150 mV

• Dual-Mode 1x and 2x Charge Pump

• Drives up to 3 + 3 + 3 Channels of LEDs

Applications

• Mobile Phone White LED Backlighting and Indicators

• PDA White LED Backlighting

• Battery-operated Phone Main and Sub Screen White LED

Backlighting

• 1.2 MHz Constant Switching Frequency
short circuit and Thermal Protections

• V

OUT

• Soft Start for reducing inrush current

• Under Voltage Lockout Protection

• I

<1µA in Shutdown

Q

• Thermally-Enhanced QFN3030-20 Package: Available in “Green”

Molding Compound (No Br, Sb)

• Lead Free Finish/ RoHS Compliant (Note 1)

Notes: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied. Please visit our website at

http://www.diodes.com/products/lead_free.html

Typical Application Circuit

2.2uF
C

IN

8

V

IN

AL3158

3

EN1

5

EN2

4

EN3

PGND

6

V

IN

EN1

EN2

EN3

AL3158

Document number: DS35047 Rev. 2 - 2

GND

9

C

P

7

C

N

11

V

OUT

D1

LED

12

D1

13

D2

14

D3

15

D4

16

D5

18

D6

20

D7

1

D8

2

D9

17

D2

LED

1uF

C

1

EN1 EN2

D4

D3

LED

LED

D5

LEDD6LEDD7LEDD8LEDD9LED

EN3

2.2uF
C

OUT

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Pin Descriptions

Pin Name Pin Number Description

D8 1 Current sink input #8. Connected to VOUT when un-used.

D9 2 Current sink input #9. Connected to VOUT when un-used.
EN1 3 Enable Pin 1
EN3 4 Enable Pin 3
EN2 5 Enable Pin 2

PGND 6 Charge Pump Switch Ground

CN 7 Negative Terminal of Flying Capacitor

VIN 8 Input Power Supply. Requires 2.2µF capacitor between this pin and ground.

CP 9 Positive Terminal of Flying Capacitor
NC 10,19 No-Connect

V

OUT

D1 12 Current sink input #1. Connected to V

D2 13 Current sink input #2. Connected to V

D3 14 Current sink input #3. Connected to V

D4 15 Current sink input #4. Connected to V

NEW PRODUCT

D5 16 Current sink input #5. Connected to V

D6 18 Current sink input #6. Connected to V

GND 17 Ground

D7 20 Current sink input #7. Connected to V

GND EP PAD Exposed Pad (bottom). Connected to GND directly underneath the package.

11

Charge pump output to drive load circuit. Requires 2.2µF capacitor between this pin
and ground.

AL3158

HIGH EFFICIENCY 1x/2x CHARGE PUMP

FOR WHITE LED APPLICATIONS

when un-used.

OUT

when un-used.

OUT

when un-used.

OUT

when un-used.

OUT

when un-used.

OUT

when un-used.

OUT

when un-used.

OUT

Functional Block Diagram

AL3158

Document number: DS35047 Rev. 2 - 2

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© Diodes Incorporated

HIGH EFFICIENCY 1x/2x CHARGE PUMP

FOR WHITE LED APPLICATIONS

Absolute Maximum Ratings (Note 2)

Symbol Description Rating Unit

ESD HBM Human Body Model ESD Protection 2 KV

ESD MM Machine Model ESD Protection 200 V

VIN Input Voltage -0.3 to 6 V

V

EN1, EN2, EN3 to GND Voltage -0.3 to VIN +0.3 V

EN1,2,3

I

Maximum DC Output Current 270 mA

OUT

TJ Operating Junction Temperature Range 150

T

Maximum Soldering Temperature (at leads, 10 sec) 300

LEAD

Notes: 2. Exceeding Absolute Maximum Ratings will cause permanent damage to the device.

Recommended Operating Conditions

Symbol Parameter Min Max Unit

VIN Input Voltage 2.7 5.5 V
TA Operating Amb ient Temperature -40 85 °C

NEW PRODUCT

Electrical Characteristics (T

Symbol Parameter Test Conditions Min Typ. Max Unit

IQ Quiescent Current

I

Shutdown Current EN1, EN2, EN3 = 0 1 µA

SHDN

I

IDX

I

D-Match

R

Open Loop V

out

VTH
VHS Mode Transition Hysteresis 250 mV

TSS Soft-Start Time 100 µs

Fsw Switching Frequency 1.2 MHz

V

EN1, 2,3 (L)

V

EN1,2,3(H)

T

EN1,2,3 Threshold Low VIN = 2.7V 0.4 V
EN1,2,3 Threshold High VIN = 5.5V 1.4 V

EN1,2,3 Off Timeout 20 ms

EN1,2,3

UVLO VIN Under-Voltage Lockout 1.8 2 2.2 V
I

EN1,2,3 Input Leakag e -1 1 µA

EN1,2,3

T

SHDN

T

HYS

θ

JA

Notes: 3. Determined by the average current levels of all active channels.

4. Determined by the maximum sink current (MAX), the minimum sink current (MIN), and the average sink current (AVG). Two matching numbers are
calculated as (MAX-AVG)/AVG and (AVG-MIN)/AVG. The largest number of the two (worst case) is considered as the matching data.

5. Device mounted on FR-4 substrate, 2"*2", 2oz copper, double-sided PC board, with minimum recommended pad on top layer and
4 vias to bottom layer.

Current Accuracy (Note 3)

SINK

Current Matching Between Any Two
Current Sink Inputs (Note 4)

OUT

1x to 2x Transition Threshold at Any

Pin

I

SINK

Thermal shutdown Protection 160
Thermal shutdown hysteresis 10
Thermal Resistance Junction-to-

Ambient

= 25°C, Vin = 3.6V, CIN = C

A

Resistance

= 2.2µF, C1 = 1µF Unless otherwise noted)

OUT

1x Mode, 3.0≤VIN≤5.5, Active,
No Load Current

2x Mode, 3.0≤VIN≤5.5, Active,
No Load Current

0.3 0.6

2 5

19 20 21 mA
VF: D1:D9 = 3.6V 1 2 %

1x mode 0.5
2 x mode 4.5

= 20mA 150 mV

I

DX

QFN3030-20 (Note 5)

52

AL3158

°C
°C

mA

Ω

°C
°C

o

C/W

AL3158

Document number: DS35047 Rev. 2 - 2

3 of 10

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January 2011

© Diodes Incorporated