ON Semiconductor NCP5008, NCP5009 Technical data

NCP5008, NCP5009

Backlight LED Boost Driver

The NCP5008/NCP5009 is a high efficiency boost converter operating in current loop control mode to drive Light Emitting Diode. The current mode regulation allows a uniform brightness of the LEDs.

Features

• 2.7 to 6.0 V Input Voltage Range

• Output Voltage from V

to 15 V

bat

• 3.0 mA Quiescent Supply Current

• Automatically LEDs Current Matching

• No External Sense Resistor

• Includes Dimming Function

• Programmable or Automatic Current Output Mode

• LOCAL or REMOTE Control Facility

• Photo Transistor Sense Feedback Input

• Inductor Based Converter brings High Efficiency

• Low Noise DC/DC Converter

• All Pins are Fully ESD Protected

• Pb−Free Package is Available

T ypical Applications

• LED Display Back Light Control

• High Efficiency Step Up Converter

30 k

GND

NPN−PHOTO

GND

LED

GND

Vcc

MICROCONTROLLER

Figure 1. Typical Battery Powered LED Boost Driver

April, 2006 − Rev. 7

ref

PHOTO

bat

4 8

VBIAS

5 6

CLK NCP5009

LED

2.2 mF/16 V

GND

LOCAL

LED

bat

LED

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Micro 10

DM SUFFIX

(Note: Microdot may be in either location)

CASE 846B

5Tx = Device Number

x = 8 or 9 A = Assembly Location Y = Year W = Work Week G = Pb−Free Package

PIN CONNECTIONS

110

ref

bat

10 mF/6.3 V

GND

22 mH

D5 MBR0520

GND

VBIAS

CLOCK

Photo

VBIAS

CLOCK

3 4 5 LOCAL

NCP5008

110

ref

2 3 4 5

NCP5009

ORDERING INFORMATION

Device Package Shipping

NCP5008DMR2 Micro 10 NCP5008DMR2G

NCP5009DMR2 Micro 10 †For information on tape and reel specifications,

including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specification Brochure, BRD8011/D.

1 Publication Order Number:

Micro 10

(Pb−Free)

4000 / Tape & Ree 4000 / Tape & Ree

4000 / Tape & Ree

MARKING DIAGRAM

AYW G

bat

9 8

L2 Iout

GND

bat

9 8

L2 Iout

GND

LOCAL

NCP5008/D

5Tx

†

NCP5008, NCP5009

BACK LIGHT WHITE LED CURRENT DRIVE CONTROLLER

bat

VBIAS

CLK

LOCAL

ref

PHOTO

(See Note)

1 2

BandGap

50 k

bat

50 k

bat

Latches

Serial To Parallel

POR

1:8

Selection V

bat

POR

1R8

A=10

Isense

−

Iout Reference

bat

ref

GND

POR

ref

bat

Iout

CONTROLLER

GND

bat

_OK

bat

−

BANDGAP

REFERENCE

GND

NOTE: This functionality is NOT implemented on the NCP5008 type.

Figure 2. Block Diagram

BandGap

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NCP5008, NCP5009

PIN FUNCTION DESCRIPTION

Pin Symbol Type Description

1 I

ref

2 PHOTO SIGNAL This pin provides an access to the output current control loop for the NCP5009 version. The cur-

3 CS INPUT Negative going Chip Select logic input. This pin is used to select the NCP5008/ NCP5009 and

4 VBIAS POWER This pin should be connected to V 5 CLOCK INPUT The clock signal connected to this pin is used to serially shift right the internal preset high logic

6 LOCAL INPUT This pin is used to select the mode of operation.

7 GND POWER This pin is the system ground for the NCP5008/NCP5009 and carries both the Power and the

8 L2 POWER This pin is the power side of the external inductor and must be connected either to the external

9 L1 POWER The return side of the external inductor shall be connected to this pin. Typical application will use a

10 V

bat

INPUT This pin provides the output current range adjustment by means of a resistor connected to

ground. The current output tolerance depends upon the accuracy of this resistor. Using a "1% metal film resistor, or better, yields the best output current accuracy.

rent sunk to ground from this pin is subtracted from the output current mirror. Primary use is the ambient light automatic adjustment by means of an external photo transistor connected across this pin and ground. The output current decreases as the ambient light increases. The internal circuit provides a 1/1 current ratio with the I ground. This current shall be limited to 65 mA.

defined by the resistor connected from pin 1 to

ref

This functionality is NOT implemented on the NCP5008 type.

validate the clock/data when CS = Low. The internal shift register is automatically clear to zero upon the falling edge, thanks to a 20 ns built−in one shoot. The built−in pull−up resistor disables the device when the CS pin is left open.

bat

level. The clock is valid between the falling edge and until the rising edge of the CS. There is neither a feedback nor an overflow control. If the clock count exceeds 8 bits, the internal register is clear, the output current is forced to zero and the device comes back to the shutdown mode.

• When LOCAL = High or Open, the chip is controlled by two digital lines:CS and CLOCK. The output current is programmed by the logic control of these pins, allowing a current adjustment

within the range defined by the I

resistor.

ref

• When LOCAL = Low, the chip is turned ON /OFF by means of the CS line, the CLOCK pins being deactivated. The output current is constant, as defined by the I

resistor value.

ref

In order to minimize the standby current a dynamic pull−up resistor is activated when POR is High, this pull−up resistor being disconnected when LOCAL = Low.

Digital signals. High quality ground must be provided to avoid spikes and/or uncontrolled operation. Care must be observed to avoid high−density current flow in a limited PCB copper track.

Schottky diode (see Figure 22) or directly to one external LED (see Figure 23). It provides the output current to the load. Since the boost converter operates in a current loop mode, the output voltage can range up to +15 V but shall not extend this limit. The user must make sure this voltage will not be exceeded during the normal operation of this part.

An external low cost ceramic capacitor (2.2 mF/16 V , ESR < 100 mW) is recommended to smooth the current flowing into the diode(s), thus limiting the noise created by the fast transients present in this circuitry.

Care must be observed to avoid EMI though the PCB copper tracks connected to this pin.

22 mH, size 1210, to handle the 2.8 to 364 mA max range. On the other hand, when the desired output current is above 20 mA, the inductor shall have an ESR < 1.0 W. The output current tolerance can be improved by using a larger inductor value.

POWER The external voltage supply is connected to this pin. A high quality reservoir capacitor must be

connected across pin 10 and Ground to achieve the specified output voltage parameters. A 10 mF/6.3 V , low ESR capacitor must be connected as close as possible across pin 10 and ground pin 7. The X5R ceramic types are recommended.

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NCP5008, NCP5009

T able 1. Shift Register Bits Assignment and Functions

SetReg shift register (Note: The register content is latched upon CS positive going).

B7 B6 B5 B4 B3 B2 B1

Bn Value After POR 0 0 0 0 0 0 0 Iout Peak (mA) I

LOCAL CLOCK CS B1−B7 Output Current

L X H X 0

L X L X I H or Open X H No Change I H or Open ↓ L No Change I H or Open ↑ L Q

The register is clear to 0 during the first 20 ns following the CS falling edge.

Note:

Coefficient Value (internal ratio): k = 746 Maximum output peak current @ B7 = 1 and Iphoto = 0 mA :Iout peak = I

ref

1.24 V R1

ref

*k*7.5 I

ref

*k*6.5 I

ref

*k*5.5 I

ref

data

*k*4.5 I

ref

*k*3.5 I

ref

→ Bn I

* (7 + 0.5) * 746 = I

ref

*k*2.5 I

ref

* k

ref

* k * (Bn + 0.5)

ref

* k * (Bn + 0.5)

ref

* k * (Bn + 0.5)

ref

* 5595

ref

*k*1.5

MAXIMUM RATINGS

Rating Symbol Value Unit

Power Supply V Output Power Supply Voltage Compliance V Digital Input Voltage

Digital Input Current Human Body Model: R = 1500 W, C = 100 pF ESD "2.0 kV Machine Model ESD "200 V Micro 10 Package

Power Dissipation @ T Thermal Resistance, Junction−to−Air

= +85°C

Operating Ambient Temperature Range T Operating Junction Temperature Range T Maximum Junction Temperature T Storage Temperature Range T

Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability.

bat

, V

BIAS

7.0 V 16 V

CLK, CS −0.3 tV tV

1.0

Jmax

Thja

stg

200 200

−25 to +85 °C

−25 to +125 °C +150 °C

−65 to +150 °C

+ 3.0 V

bat

°C/W

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NCP5008, NCP5009

POWER SUPPLY SECTION (−25°C to +85°C ambient temperature, unless otherwise noted.)

Rating Pin Symbol Min Typ Max Unit

Power Supply 10 V Power Supply Threshold Startup Voltage 10 V Output Load Voltage Compliance 8 V Pulsed Current Regulation Range 8 I Continuous DC Current in the Load 8 I Output Pulsed Current Tolerance @ V

ref

"1%, I

= 20 mA (Note 1)

LED

Output Leakage @ LOCAL = 0, CS = H, Vout = 15 V, V Standby Current @ Iout = 0 mA, CS = H, CLK = H, V Standby Current @ Iout = 0 mA, CS = H, CLK = H, V Operating Current @ V

LOCAL = Open

bat

= V

BIAS

Boost Internal Oscillator Clock @ L1 = 22 mH, V Iout = 20 mA (Vout = 14 V)

= 3.6 V , L1 = 22 mH/0.71 W,

bat

bat bat

= 3.6 V , I

= 30 mA, CLK = H, CS = L,

ref

= V

bat

8 I

= 6.0 V 8 I

bat

= V

= 3.6 V 10 I

BIAS

= V

= 6.0 V 10 I

BIAS

10 I

BIAS

= 3.6 V ,

− F

1. The tolerance refers to the 20 mA to 70 mA current range.

DIGITAL SECTION (−25°C to +85°C ambient temperature, unless otherwise noted.)

Rating Pin Symbol Min Typ Max Unit

High Level Input Voltage (Note 2) Low Level Input Voltage (Note 2) Input Capacitance

LOCAL Pullup Resistor 6 R LOCAL Leakage Current 9 I CS Pullup Resistor 3 R Minimum CS Low Time 3 Tcs Clock Frequency 5 F CLOCK tr and tf 5 tr Internal Register Clear − t Internal Power on Reset Width − t

2. Digital inputs undershoot < − 0.30 V, Digital inputs overshoot < 0.30 V.

3, 5 V

6 V

batThr

out out out

out stdb stdb

ope

osc

V C

Loc

CLK

clear POR

bat

out

IH IL

loc

setup

, tf

CLK

2.7 − 6.0 V

− 2.3 2.7 V

− − 15.0 V 0 − 400 mA

− − 75 mA

− "5.0 − %

− − 500 nA

− 3.0 − mA

− − 10 mA

− 600 −

− 300 − kHz

0.7*V

bat

−

0.6*V

0.4*V 10

−

bat bat

0.3*V

bat

−

bat

20 − 80 kW

− − 100 nA

20 − 80 kW

250 − − ns

− − 5.0 MHz 10 − − ns 10 30 − ns

− 100 − ms

V V

ANALOG SECTION (−25°C to +85°C ambient temperature, unless otherwise noted.)

Rating Pin Symbol Min Typ Max Unit

Output Voltage Range Reference @ 2.5 mA < I Maximum Output Current Range Ratio 8 I Minimum Output Current Range Ratio 8 I Output Current Sense Resistor 10, 9 R Output Voltage Range Reference @ 2.5 mA < Ipho < 65 mA 2 V Output Current Stabilization tdelay following a DC/DC startup 8 I Internal NMOS Resistor @ V

= 3.6 V 8 QR

bat

Internal Comparator Delay Time − Td

< 65 mA (Note 3) 1 V

ref

ref out out

pho

outdly

DSON

comp

1.20 1.24 1.28 V

− 5595 − −

− 1119 − −

− 1.8 5.0 W

1.20 1.24 1.28 V

− 100 − ms

− 2.2 3.0 W

− 60 − ns

3. The overall tolerance depends upon the accuracy of the external resistor. Using a 1%/low PPM metal film resistor is recommended to achieve "5% output current tolerance.

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NCP5008, NCP5009

EFFICIENCY (%)

load

ref

EFFICIENCY (%)

TYPICAL OPERATING CHARACTERISTICS

Condition: T ypical Application: L = 22 mH, Cin = 10 mF, Cout = 2.2 mF, R1 = 30 kW

= 4.2 V

bat

= 3.6 V

bat

= 3.0 V

0 5 10 15 20 25 30 35

(mA)

LED

Figure 3. Efficiency vs. Load Current @ 4 LEDS

= 4*Vf ⇒ 14.2 V)

load

bat

= 4.2 V

bat

= 3.6 V

= 3.0 V

bat

EFFICIENCY (%)

= 3.0 V

bat

0 5 10 15 20 25 30 3

(mA)

LED

Figure 4. Efficiency vs. Load Current @ 3 LEDS

= 3*Vf ⇒ 10.5 V)

load

100

bat

out

= 40 mA

led

out

= 20 mA

led

= 4.2 V

= 3.6 V

=7.5 V

= 15 V

EFFICIENCY (%)

0 5 10 15 20 25 30 35

(mA)

LED

Figure 5. Efficiency vs. Load Current @ 2 LEDS

= 2*Vf ⇒ 7.1 V)

load

100

= 6.0 V

bat

5.0 V

4.2 V

3.6 V

2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 V

(V)

bat

Figure 6. Efficiency vs. V

(mA)

peak

400 350 300 250 200 150 100

out

= 15 V/I

= 7.5 V/I

= 20mA and

led

= 40 mA

led

bat

7 6

5 4

3 2

3.0 V

0 1020304050 6070

(mA)

LED

Figure 7. Efficiency vs. Load Current @ 4 LEDS

= 2 strings of 2 LEDs in series = 7.1V)

0 2040608

(mA)

ref

Figure 8. Inductor peak Current vs.

@ Bn = {1, 2, 3, 4, 5, 6, 7}

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