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Ordering number : ENA0089
CMOS IC
LC410591FN
Overview
Power Supply IC with Built-in White LED Charge Pump
The LC410591FN is a power supply IC for white LEDs. It incorporates a charge pump-type DC/DC converter circuit and has four constant-current outputs. The input voltage ranges from 2.7V to 5.5V. The maximum value of the current flowing to the LEDs can be determined by the resistance value of the external resistors. The LC410591FN can supply a total current of 105mA for one to four white LEDs. A maximum current of 26mA can be supplied to one white LED when driving four LEDs, and a maximum current of 35mA can be supplied to one white LED when driving three LEDs. The IC operates at a fixed frequency of 600kHz without using an inductor, resulting in very low EMI noise. The LED brightness is adjusted by a PWM pulse signal to the BRGT pin. When a low level is applied for 22ms or longer to the BRGT pin, the IC enters the shutdown mode. This IC comes in the VQFN16 package (4mm x 4mm).
Features
* Built-in low-noise and high-efficiency CMOS charge pump * Built-in constant-current generating circuit * Input voltage range of 2.7V to 5.5V * Driving of 1 to 4 white LEDs at a total current of 105mA * Automatic switching of charge pump voltage step-up ratio (x1, x1.5) * 1.5% (typ) LED to LED current matching * Soft start for preventing rush current * Charge pump frequency of 600kHz * Brightness adjustment control with a PWM signal * 1A maximum shutdown current
Applications
* White LED display backlights * White LED keypad backlights * PDAs, cell phones, FPDs, and other equipment that operate with a single lithium-ion battery
Any and all SANYO Semiconductor products described or contained herein do not have specifications that can handle applications that require extremely high levels of reliability, such as life-support systems, aircraft's control systems, or other applications whose failure can be reasonably expected to result in serious physical and/or material damage. Consult with your SANYO Semiconductor representative nearest you before usingany SANYO Semiconductor products described or contained herein in such applications. SANYO Semiconductor assumes no responsibility for equipment failures that result from using products at values that exceed, even momentarily, rated values (such as maximum ratings, operating condition ranges, or other parameters) listed in products specifications of any and all SANYO Semiconductor products described or contained herein.
N0106HKIM B8-9151 No.A0089-1/11
LC410591FN
Specifications
Absolute Maximum Ratings at Ta = 25C
Parameter Maximum supply voltage Maximum supply voltage Storage Temperature Symbol VDD VSS Tstg Conditions Ratings -0.3 to +7.2 -0.3 to +0.3 -55 to +125 Unit V V C
Allowable Operating Range at Ta=-40C to 85C (unless otherwise specified, Ta=25C) Supply voltage (VIN)=3.6V, RSET=3.2k, LED forward voltage (VF)=3.2V, input bypass capacitor (CIN)=2.2F, output smoothing capacitor (CCP)=2.2F
Parameter Supply voltage Maximum output current Maximum LED current (per 1 LED) Symbol VIN Ta=25C Ta=25C, 4 LEDs lit Ta=25C, 3 LEDs lit No-load supply current (100% ILED) VIN=4.1 to 5.5V (x1 mode) VIN=2.7 to 4.1V (x1.5 mode) Charge pump frequency Charge pump mode-switching supply voltage Charge pump mode-switching supply voltage hysteresis Reference voltage output ISET bias LED current absolute accuracy LED to LED current matching Shutdown time supply current Input signal frequency (PWM) BRGT signal high threshold value VIN=2.7 to 5.5V,Ta=25C BRGT input Ta=25C,VIN=4.5 to 5.5V Ta=25C,VIN=2.7 to 4.5V BRGT signal low threshold value BRGT input current (H level) BRGT input current (L level) Ta=25C,VIN=2.7 to 5.5V Ta=25C Ta=25C -1 100 3 2.5 0.5 1 When switching from x1 to x1.5 Conditions min 2.7 105 26 35 2 5 600 4.1 0.5 1.2 1.2 3 1.5 1 50k Ratings typ max 5.5 V mA mA mA mA mA kHz V V V V % % A Hz V V V A A Unit
(Note 1) Electrical characteristics at Ta=-40C indicate design guaranteed values.
No.A0089-2/11
LC410591FN
Package Dimensions
unit : mm (typ) 3316
TOP VIEW 4.0 3.75 12 13 9 8
3.75 4.0
SIDE VIEW
BOTTOM VIEW Exposed Die-Pad Do Not Connect 9 8
(2.50)
12 (2.50) 13
16 1 4
5
0.6
5 4 0.65 (1.025) 1
16
SIDE VIEW
(0.85)
0.28
0.01
0.9 MAX
SANYO : VQFN16(4.0X4.0)
Application Example
2.2F
LED_IN1
1F
C1A C1B C2A C2B
LED_IN2 LED_IN3 LED_IN4
1F
BRGT VREF
GND
1nF
ISET
2.2F
ILC01756
VIN
VCP
No.A0089-3/11
LC410591FN
Pin Assignment
12
LED_IN1
11
LED_IN2
10
LED_IN3
9
LED_IN4
13
ISET
GND
8
14
TEST*
C1B
7
15
BRGT
C2A
6
16
VREF
NC** C2B C1A VIN
VCP
5
Top view
1
2
3
4
ILC01757
Pin Functions
Pin Name VIN C1A C1B C2A C2B BRGT Pin No. 2 4 7 6 3 15 Pin Description Power supply input pin. Connects a capacitor of 2.2F between the VIN pin and GND pin. Flying capacitor (1)+ Flying capacitor (1)Flying capacitor (2)+ Flying capacitor (2)LED brightness adjustment signal input. LED current is adjusted by PWM signal (max. 50kHz). The LED current changes linearly with respect to the PWM signal duty ratio and the brightness changes. When the low level continues for 22ms or longer, the LC410591FN enters the shutdown mode, and the LED turns off. ISET VREF GND LED_IN1 to 4 VCP TEST 13 16 8 9-12 5 14 External resistor pin. The maximum LED current is determined by ILED(mA)=48/RSET(k). Internal reference voltage output (standard 1.2V). Connect a capacitor of 1nF between the VREF pin and GND pin. The VREF pin must always be set to a high impedance state. Power supply GND. The switching current of the charge pump flows to this pin. Connect LEDs between the VCP pin and LED_IN1 to IN4. If not connected, set these pins to OPEN or connect to GND. Charge pump output. Connect a capacitor of 2.2F between the VCP pin and GND pin. Not used. Always set to OPEN.
No.A0089-4/11
LC410591FN
Block Diagram
VIN
VCP Boost Mode Selector Soft Start Circuit Current Mirror
2.2F
1F
Charge Pump
1F
LED_IN1 to 4
Oscillator
Clock Generator Brightness Controller
BRGT Band Gap Reference VREF
1nF
ISET
RSET
ILC01758
2.2F
No.A0089-5/11
LC410591FN
Standard Electrical Characteristics
Unless otherwise specified, Supply voltage (VIN)=3.6V, RSET=3.2k, LED forward voltage (VF)=3.2V, Ta=25C, 4-light control input bypass capacitor (CIN)=2.2F, output smoothing capacitor (CCP)=2.2F, flying capacitor (C1,C2)=1F
20
LED Current - Supply Voltage
20
LED Current - Supply Voltage
15
Vf =3.2V
LED Current - mA
15
60C 25C
LED Current - mA
Vf =3.4V
10
10
5
5
0 3.0
3.5
4.0
4.5
5.0 ILC01759
0 3.0
3.5
4.0
4.5
5.0 ILC01760
Supply Voltage - V
100
Supply Voltage - V
80
LED Efficiency - Supply Voltage
LED Efficiency - Supply Voltage
80 60
LED Efficiency - %
LED Efficiency - %
Vf = 3.6V
60
60C 25C
Vf = 3.2V
Vf =3 .4V
40
40
20 20
0 3.0
3.5
4.0
4.5
5.0 ILC01761
0 3.0
3.2
3.4
3.6
3.8
4.0
4.2
4.4
4.6
4.8
5.0
Supply Voltage - V
100
Supply Voltage - V
100
ILC01762
Supply Current - Supply Voltage
Supply Current - Supply Voltage
80
80
Supply Current - mA
Vf =3.2V
60
Supply Current - mA
60
60C 25C
Vf =3.6V
40
V f =3.4V
40
20
20
0 3.0
3.5
4.0
4.5
5.0 ILC01763
0 3.0
3.5
4.0
4.5
5.0 ILC01764
Supply Voltage - V
Supply Voltage - V
No.A0089-6/11
LC410591FN
Unless otherwise specified, Supply voltage (VIN)=3.6V, RSET=3.2k, LED forward voltage (VF)=3.2V, Ta=25C, 4-light control input bypass capacitor (CIN)=2.2F, output smoothing capacitor (CCP)=2.2F, flying capacitor (C1,C2)=1F
100
Charge Pump Efficiency - Supply Voltage
25C
Supply Current - Supply Voltage
6
Charge Pump Efficiency - %
80
60C
Supply Current - mA
5
60C 25C
4
60
3
40
2
20
1
0 3.0
3.5
4.0
4.5
5.0 ILC01765
0 3.0
3.5
4.0
4.5
5.0 ILC01766
Supply Voltage - V
120
Supply Voltage - V
50
LED Current - Duty Ratio of BRGT signal
LED Current - BRGTs Duty Ratio
100
40
Current of 4 LEDs - mA
80
LED Current - mA
60
40
k =2 ET RS = 3k RSET
30
C 60 5C 2
20
20
10
0 0 20 40 60 80 100 ILC01767
0 0
20
40
60
80
100 ILC01768
Duty Ratio - %
30
Duty Ratio - %
6
LED Current - Supply Voltage
RSET=2k
Output Voltage- V
Output Voltage - Supply Voltage
C 60 C 25
25
5
LED Current - mA
20
4
15
RSET=3.3k
3
10
2
5
1
0 3.0
3.5
4.0
4.5
5.0 ILC01769
0 3.0
3.5
4.0
4.5
5.0 ILC01770
Supply Voltage - V
Supply Voltage - V
No.A0089-7/11
LC410591FN
Functional Description
Circuit description The LC410591FN is a white LED driver that uses a Li-ion battery as its power supply. The output voltage range of the Li-ion battery is approximately 2.7V to 5.5V, and a typical white LED forward voltage (VF) is approximately 3.6V. Therefore, when the supply voltage is 3.6V or less, the voltage must be stepped up internally. The LC410591FN incorporates a charge pump that steps up the supply voltage 1.5 times. This charge pump automatically switches to the optimum step-up mode. The 100% LED current is determined by the resistance values of the external resistors. In other words, the internal reference voltage (VREF1.2) is applied precisely to the external resistors by the internal Op amplifier, and the current flowing to the external resistors (IRSET) becomes IRSET=VREF/RSET. The LED current (ILED) is regulated by a current mirror circuit so that 40 times the IRSET current flows. For example, if VREF=1.2V and RSET=2k, then IRSET=0.6mA, and ILED=IRSETx40=24mA. In this case, for 4-light control, the total current flowing to the LED is 24mAx4=96mA. However, this formula does not include the variation in the resistance values of the external resistors. If accurate LED current is required, high-precision resistors (with a variation of 1% or less, for instance) may be required. The LED brightness is adjusted by a serial signal to the BRGT pin. Shutdown mode The LC410591FN enters a shutdown mode when the low level is applied to the BRGT pin for 22ms or longer. In the shutdown mode, the LEDs turn off, and the supply current is reduced to 1A or less. Soft start The LC410591FN performs a soft start to prevent rush current, and then 100% current flows to the LEDs. A rush current is generated if the charge pump is activated when the flying capacitor is discharged. If the impedance of the capacitor is low, an excessive current will flow in from the battery. Soft start is performed to reduce the stress on the battery and external components. During the soft start, the resistance of the switch connected to the flying capacitor and output smoothing capacitor is adjusted to prevent a rush current. Brightness adjustment LED brightness can be adjusted by controlling the current to the LED with the PWM signal supplied to the BRGT pin. The average current flowing to the LEDs depends on the PWM signal. [LED average current=ILEDxDuty ratio] ...(Fig. 2) The current flowing to the LED (average value) changes in a nearly linear fashion with respect to the duty ratio of the PWM signal input to the BRGT pin. ...(Fig. 3) The upper limit of the PWM signal frequency is 50kHz. Fix the BRGT signal to the low level for at least 22ms from power supply (VIN) rising....(Fig. 4)
T t LED current ILED Duty ratio=t/T (Fig. 2) Frequency=1/T
70
ILED - BRGT Duty
60
VIN=3.6V,Rset=3.3k BRGT=1kHz,4LEDs
50
ILED - mA
40
30
22ms or longer
20
10
VIN BRGT (Fig. 4)
0 0
20
40
60
80
100 ILC01771
BRGT Duty - %
(Fig. 3)
No.A0089-8/11
LC410591FN
Selection of external capacitors Low ESR capacitors are recommended for the input bypass capacitor, output smoothing capacitor, and charge pump flying capacitor. Also, ceramic capacitors are recommended for their low fluctuations due to temperature (such as X5R or X7R). Adding LEDs for driving Shown in Figures 5 and 6 are sample circuit diagrams illustrating the use of output voltage (VCP) of this IC when an LED is added. Note that the IC may not be able to conform to its specifications if the total LED current exceeds 105mA. To limit the amount of current to the additional LED, or to control the on/off switching of the current, it is necessary to connect a resistor or switch in series with the added LED.
2.2F
LED_IN1
1F
C1A C1B C2A C2B
LED_IN2 LED_IN3 LED_IN4
1F
BRGT VREF
1nF
GND
ISET
2.2F
VIN
VCP
ILC01772
(Fig. 5)
No.A0089-9/11
LC410591FN
The connection shown in the figure below is also possible.
2.2F
LED_IN1
1F
C1A C1B C2A C2B
LED_IN2 LED_IN3 LED_IN4
1F
BRGT VREF
1nF
GND
ISET
(Fig.6)
However, in the case of the above connection, LED current differences due to the characteristic differences of the LEDs connected to the same LED_IN by the cathode (Fig. 7) are not adjusted.
VCP
LED_IN1
ILC01774
(Fig.7)
2.2F
ILC01773
VIN
VCP
No.A0089-10/11
LC410591FN
Specifications of any and all SANYO Semiconductor products described or contained herein stipulate the performance, characteristics, and functions of the described products in the independent state, and are not guarantees of the performance, characteristics, and functions of the described products as mounted in the customer's products or equipment. To verify symptoms and states that cannot be evaluated in an independent device, the customer should always evaluate and test devices mounted in the customer's products or equipment. SANYO Semiconductor Co., Ltd. strives to supply high-quality high-reliability products. However, any and all semiconductor products fail with some probability. It is possible that these probabilistic failures could give rise to accidents or events that could endanger human lives, that could give rise to smoke or fire, or that could cause damage to other property. When designing equipment, adopt safety measures so that these kinds of accidents or events cannot occur. Such measures include but are not limited to protective circuits and error prevention circuits for safe design, redundant design, and structural design. In the event that any or all SANYO Semiconductor products (including technical data,services) described or contained herein are controlled under any of applicable local export control laws and regulations, such products must not be exported without obtaining the export license from the authorities concerned in accordance with the above law. No part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording, or any information storage or retrieval system, or otherwise, without the prior written permission of SANYO Semiconductor Co., Ltd. Any and all information described or contained herein are subject to change without notice due to product/technology improvement, etc. When designing equipment, refer to the "Delivery Specification" for the SANYO Semiconductor product that you intend to use. Information (including circuit diagrams and circuit parameters) herein is for example only; it is not guaranteed for volume production. SANYO Semiconductor believes information herein is accurate and reliable, but no guarantees are made or implied regarding its use or any infringements of intellectual property rights or other rights of third parties.
This catalog provides information as of November, 2006. Specifications and information herein are subject to change without notice.
PS No.A0089-11/11

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