AN75 DIODES [Diodes Incorporated], AN75 Datasheet

no-image

AN75

Manufacturer Part Number
AN75
Description
High Power Factor LED Replacement T8 Fluorescent Tube
Manufacturer
DIODES [Diodes Incorporated]
Datasheet

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
AN7500FA-EB
Manufacturer:
BROADCOM
Quantity:
55
Part Number:
AN7500FA-EB
Manufacturer:
PANASONIC/松下
Quantity:
20 000
Part Number:
AN7511
Manufacturer:
PAN
Quantity:
5 510
Part Number:
AN7511
Manufacturer:
PANASONIC
Quantity:
1 000
Part Number:
AN7512
Manufacturer:
GE CRITICAL POWER
Quantity:
87
Part Number:
AN7512
Manufacturer:
PANA
Quantity:
1 000
Part Number:
AN7512
Manufacturer:
PANASONIC/松下
Quantity:
20 000
Part Number:
AN7512SH-E1V
Manufacturer:
PANASONIC/松下
Quantity:
20 000
Part Number:
AN7513
Manufacturer:
PANASONIC/松下
Quantity:
20 000
Company:
Part Number:
AN7513
Quantity:
20
Part Number:
AN7513N
Manufacturer:
OKI
Quantity:
9 999
Part Number:
AN7513N
Manufacturer:
PANASONIC/松下
Quantity:
20 000
Part Number:
AN7522N
Manufacturer:
PANASONIC
Quantity:
23 000
Part Number:
AN7522N
Quantity:
20
Part Number:
AN7522N PH
Quantity:
15
Part Number:
AN7522N PH
Quantity:
5
AN75
AN75
High Power Factor LED Replacement T8 Fluorescent Tube
using the AL9910 High Voltage LED Controller
Yong Ang, Diodes Inc.
Introduction
This application note describes the principles and design equations required for the design of a high
brightness LED lamp using the AL9910. The equations are then used to demonstrate the design of a
universal, offline, high power factor (PF), 13W LED lamp suitable for use as the replacement for T8
fluorescent tube. A complete design including the electrical diagram, component list and performance
measurements are provided.
AL9910 high power factor buck LED driver
Figure 1 Electrical schematic of a high power factor 13W LED lamp
Figure 1 shows the electrical diagram of an offline 13W LED driver.
On the input side, CX1, CX2, CX3, CX4, L1 and L2 provide sufficient filtering for both differential mode
and common mode EMI noise which are generated by the switching converter circuit.
The rectified AC line voltage from the bridge rectifier DB1 is then fed into a passive power factor
correction or valley fill circuit which consists of 3 diodes and 2 capacitors. D1, D2, D3, C1, C2 improve
the input line current distortion in order to achieve PF greater than 0.9 for the AC line input.
The constant current regulator section consists of a buck converter driven by the AL9910. Normally,
the buck regulator is used in fixed frequency mode but its duty cycle limitation of 50% is not practical
for offline lamp. This problem can be overcome by changing the control method to a fixed off-time
operation.
The design of the internal oscillator in the AL9910 allows the IC to be configured for either fixed
frequency or fixed off-time based on how resistor R
is connected. For fixed off-time operation, the
T
resistor R
is connected between the Gate and R
pins, as shown in Figure 1. This converter has
T
OSC
now a constant off-time when the power MOSFET is turned off. The on-time is based on the current
Issue 1 – January 2011
1
www.diodes.com
© Diodes Incorporated 2010

Related parts for AN75

AN75 Summary of contents

Page 1

... Gate and R T now a constant off-time when the power MOSFET is turned off. The on-time is based on the current Issue 1 – January 2011 © Diodes Incorporated 2010 is connected. For fixed off-time operation, the T pins, as shown in Figure 1. This converter has OSC 1 AN75 www.diodes.com ...

Page 2

... During this time, capacitors within the valley fill circuit (C1 and C2) are in series and charged via D2 and R1. If the capacitors have identical capacitance value, the peak voltage across C1 and C2 Issue 1 – January 2011 © Diodes Incorporated 2010 AL9910’s gate voltage) × Vac 373 V 2 AN75 to LED driver; Orange: IN www.diodes.com ...

Page 3

... (min kHz μ s − 373 V IN (max kHz μ AN75 = . The valley-fill capacitor μ − DROOP IN (min) LED is set to be 20V DROOP is given by, T Ω k www.diodes.com IN(min) in (max) ...

Page 4

... V (min) OFF = AN75 below 150kHz to avoid swi(max) in the output LED current the average pk × μ 297 the LD pin is tied to the VDD pin, and the RMS current rating of the pk × μ ...

Page 5

... The calculated MOSFET junction temperature, T J(MAX × 474 109 5 AN75 and V LED(min) × × × IN(max) pk FALL swi(max) 2 × × 65ns 63.8kHz 2 is given by, ⎞ ⎟ ⎟ ⎠ DS(ON) , must ...

Page 6

... IN (max) across the diode, the conduction power loss can be F × = 202 222 mW = × 222 AMB 6 AN75 to reduce the MOSFET’s F and V . IN(min) = 202 assumed to be 80ºC. θ AMB www.diodes.com = thJA ...

Page 7

... UCY2G150MPD ECE-A1HKG4R7 EEUEE2W100U ECQU2A104ML NFR0100001009JR500 19R685C B82791G2301N001 19R335C B72207S0271K101 SPB03N60S5 UB3C-10RF1 Any Any Any Any Any Any 7 AN75 Package Mfr. SO8 Diodes Inc. SMA Diodes Inc. DO201AD Diodes Inc. DF-S Diodes Inc. 5mm pitch Panasonic Rubicon Nichicon 1.5mm pitch Panasonic 5mm pitch Panasonic 17 ...

Page 8

... Figure 2 Top layer and bottom layer layout Issue 1 – January 2011 © Diodes Incorporated 2010 8 AN75 www.diodes.com ...

Page 9

... Figure 3 Picture of the LED T8 Fluorescent replacement lamp driver Issue 1 – January 2011 © Diodes Incorporated 2010 9 AN75 www.diodes.com ...

Page 10

... Figure 6 shows the power factor across the line voltage range. Power factor greater than 0.9 can be achieved at 85Vac. Figure 5 LED driver current regulation Issue 1 – January 2011 © Diodes Incorporated 2010 ) during part of the AC line cycle, driving the LED off. LED(max) Figure 4 LED driver system efficiency 10 AN75 IN(min) www.diodes.com ...

Page 11

... Moreover the document explains how to design a system with passive power factor correction to achieve PF greater than 0.7, allowing compliant with emergent international solid state lighting standards. Issue 1 – January 2011 © Diodes Incorporated 2010 Figure 6 LED driver power factor 11 AN75 www.diodes.com ...

Page 12

... Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems. Copyright © 2011, Diodes Incorporated www.diodes.com Issue 1 – January 2011 © Diodes Incorporated 2010 IMPORTANT NOTICE LIFE SUPPORT 12 AN75 www.diodes.com ...

Related keywords