ISL6745ALEVAL3Z Intersil, ISL6745ALEVAL3Z Datasheet

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ISL6745ALEVAL3Z

Manufacturer Part Number
ISL6745ALEVAL3Z
Description
EVAL BOARD 3 FOR ISL6745
Manufacturer
Intersil
Datasheets

Specifications of ISL6745ALEVAL3Z

Lead Free Status / RoHS Status
Lead free / RoHS Compliant

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Part Number:
ISL6745ALEVAL3Z
Manufacturer:
Intersil
Quantity:
5
Abstract
The ISL6745ALEVAL3Z is a low cost, high performance LED
driver with power factor correction function, and is
compatible with the widely used wall dimmers. It uses
Intersil’s voltage mode PWM controller ISL6745A to operate
a SEPIC converter in discontinuous conduction mode
(DCM). The design gives high flexibility on both the input
side and output load. With the same circuit configuration, it
works well with and without a triac dimmer. While connecting
to any AC source from 50V to 140V without dimmer, it gives
high power factor correction with high waveform factor of the
input current. As it is powered through a phase controlled
wall dimmer, the averaged rectified voltage varies as to the
phase angle of the wall dimmer. The brightness of the LED is
dimmed by changing the LED current, which is proportional
to the averaged rectified voltage. This driver circuit can be
used for various LED lighting applications. The number of
LEDs in a string can be as many as 14, or as few as 4.
Therefore, this design provides the luminaire manufacturers
a high performance, low-cost solution for LED drivers
compatible with the TRIAC phase-control dimmers.
Design Specifications
Configuration with Sinusoidal AC Source
• Input V
• Typical Power Factor PF: 0.98
• Typical Efficiency η: 80%
• Output Current I
• Output Voltage V
• Switching Frequency F
• Output Voltage Ripple V
AC
: 50V ~140V
AC
LED
OUT
: 10mA ~ 670mA
DIMMER
: 10V ~ 46V
TRIAC
S
: 100kHz
RPP
®
: 50mV(
1
Application Note
P-P
ISL6745ALEVAL3Z: TRIAC Dimmer Compatible
BRIDGE
R1
)
|VAC|
FIGURE 1. SYSTEM BLOCK DIAGRAM
GENERATING
REFERENCE
DIMMING
1-888-INTERSIL or 1-888-468-3774
C1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
L1
RCS
High Brightness White LED Driver
CONTROLLER
ISL6745A
Q1
Configuration with Phase Controlled Triac Wall
Dimmer
• Input V
• Efficiency η: 78%
• Output Current I
• Output Voltage V
• Switching Frequency F
• Output Voltage Ripple V
The System Block Diagram is shown in Figure 1, where the
triac phase controlled dimmer chops the AC voltages, and
the bridge rectifies it so the voltage applied to the SEPIC
converter (L
The duty ratio of the SEPIC switch Q
voltage mode PWM controller ISL6745A. The modulation
signal V
integrating the difference between the measured current of
the LED string ( K R
(V
performance rail-to-rail op-amp EL5420. The reference
signal (V
|V
The top and bottom view of the evaluation board
ISL6745ALEVAL3Z is shown in Figure 2. The detailed
design procedure for a discontinuous conduction mode
(DCM) SEPIC converter with power factor correction (PFC)
is discussed in Application Note AN1411, available on
Intersil’s website.
C2
PWM
AC
x
). The circuit is implemented with Intersil’s high
PWM
|.
ERR
L2
All other trademarks mentioned are the property of their respective owners.
x
AC
July 28, 2009
) is derived from the rectified AC voltage over C
VERR
|
: 80V~ 140V
1
Intersil (and design) is a registered trademark of Intersil Americas Inc.
is derived from the current control circuit
D
VX
, L
2
, C
CONTROLLER
LED
CURRENT
2
OUT
OP AMP
EL5420
S
Copyright Intersil Americas Inc. 2009. All Rights Reserved
, Q
C0
I
: 10mA ~ 670mA
LED
: 10V ~ 46V
1
STRING
, D) is rectified chopped AC voltage.
s
LED
Rs
) and the reference current signal
: 100kHz
RPP
: 50mV(
1
P-P
is controlled by the
)
AN1487.0
1
,

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ISL6745ALEVAL3Z Summary of contents

Page 1

... ISL6745ALEVAL3Z: TRIAC Dimmer Compatible ® Application Note Abstract The ISL6745ALEVAL3Z is a low cost, high performance LED driver with power factor correction function, and is compatible with the widely used wall dimmers. It uses Intersil’s voltage mode PWM controller ISL6745A to operate a SEPIC converter in discontinuous conduction mode (DCM) ...

Page 2

FIGURE 2. TOP AND BOTTOM VIEW OF LED DRIVER Circuit Description Unlike the active power factor correction converters, a voltage follower works in discontinuous conduction mode with comparatively constant duty ratio (D) within each utility cycle. There is no need ...

Page 3

PHASE WIDTH OF TRIAC (MS) FIGURE 5. AVERAGE VOLTAGE vs ANGLE OF A TRIAC DIMMER The schematic diagram of the current reference ...

Page 4

... PCB layouts. Gerber files for the ISL6745ALEVAL3Z board are available upon request. The performance of the LED driver board will be evaluated with and without dimmer respectively in the next sessions for various operation conditions. FIGURE 10. TOP VIEW OF THE PCB LAYOUT FIGURE 11 ...

Page 5

V/INPUT C1: VIN 100V/DIV C4: IIN 200mA/DIV I/INPUT FIGURE 13. INPUT VOLTAGE AND CURRENT @ 110V C1: VIN 100V/DIV V/INPUT C4: IIN 200mA/DIV I/INPUT FIGURE 14. INPUT VOLTAGE AND CURRENT @ 90V C1: VIN 100V/DIV V/INPUT C4: IIN 200mA/DIV I/INPUT ...

Page 6

Typical Performance Characteristics with Dimmer See “Schematic With/Without Triac Dimming Compatible” on page 8, tables 5 and 6. Connect the P1 and P2 of the LED driver board to the AC power supply. A string of 6 Cree high power ...

Page 7

... ISL6745A datasheet, Intersil Corporation 2. ISL5420 datasheet, Intersil Corporation 3. ISL6745EVAL2Z Offline High Brightness White LED C4: IIN 200mA/DIV Driver With High Power Factor for Universal Input, Intersil Corporation application note: AN1411 4. Z. Ye, et al, “Design Considerations of a High Power Factor SEPIC Converter for High Brightness White LED Lighting Applications,” ...

Page 8

Schematic With/Without Triac Dimming Compatible ...

Page 9

... TABLE 5. ISL6745ALEVAL3Z NON-ISOLATED LED ADAPTOR WITHOUT TRIAC DIMMING NO. QTY. REFERENCE VALUE 1 1 CR1 CR2 CR3 BAT54C 4 1 CR4 BAT54 5 2 C1, C2 0.1µ 22nF 47nF DNP 2.2µ C7, C27 47µ C8, C9 1800µ C10, C24, C29 0.1µ C12 220nF 14 1 C13 ...

Page 10

... TABLE 5. ISL6745ALEVAL3Z NON-ISOLATED LED ADAPTOR WITHOUT TRIAC DIMMING (Continued) NO. QTY. REFERENCE VALUE 40 1 R15 51.1Ω R16 DNP 42 1 R17 0.18Ω R18 3.01MΩ R19 2kΩ R21 10kΩ R22 1kΩ R23, R24, R27, 10.0kΩ R28, R31, R32 48 1 R25 14.0kΩ ...

Page 11

... TABLE 6. ISL6745ALEVAL3Z NON-ISOLATED LED ADAPTOR WITH TRIAC DIMMING NO. QTY. REFERENCE VALUE 1 1 CR1 CR2 CR3 BAT54C 4 1 CR4 BAT54 5 2 C1, C2 0.1µ 22nF 47nF DNP 2.2µ C7, C27 47µ C8, C9 1800µ C10, C24, C29 0.1µ C12 220nF 14 1 C13 ...

Page 12

... TABLE 6. ISL6745ALEVAL3Z NON-ISOLATED LED ADAPTOR WITH TRIAC DIMMING (Continued) NO. QTY. REFERENCE VALUE 40 1 R15 51.1Ω R16 DNP 42 1 R17 0.18Ω R18 3.01MΩ R19 2kΩ R21 10kΩ R22 1kΩ R23, R24, 10.0kΩ R27, R28, R31, R32 48 1 R25 14.0kΩ ...

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