AN LED Demboard

Application Note, V1.1, Oct 2007
CoolSET
TM
24 V / 350 mA LED PSU Using ICE3B0365JG
Power Management & Supply
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Edition 2007-05
Published by
Infineon Technologies AG
81726 Munich, Germany
© 2007 Infineon Technologies AG
All Rights Reserved.
LEGAL DISCLAIMER
THE INFORMATION GIVEN IN THIS APPLICATION NOTE IS GIVEN AS A HINT FOR THE IMPLEMENTATION
OF THE INFINEON TECHNOLOGIES COMPONENT ONLY AND SHALL NOT BE REGARDED AS ANY
DESCRIPTION OR WARRANTY OF A CERTAIN FUNCTIONALITY, CONDITION OR QUALITY OF THE
INFINEON TECHNOLOGIES COMPONENT. THE RECIPIENT OF THIS APPLICATION NOTE MUST VERIFY
ANY FUNCTION DESCRIBED HEREIN IN THE REAL APPLICATION. INFINEON TECHNOLOGIES HEREBY
DISCLAIMS ANY AND ALL WARRANTIES AND LIABILITIES OF ANY KIND (INCLUDING WITHOUT
LIMITATION WARRANTIES OF NON-INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OF ANY
THIRD PARTY) WITH RESPECT TO ANY AND ALL INFORMATION GIVEN IN THIS APPLICATION NOTE.
Information
For further information on technology, delivery terms and conditions and prices, please contact the nearest
Infineon Technologies Office (www.infineon.com).
Warnings
Due to technical requirements, components may contain dangerous substances. For information on the types in
question, please contact the nearest Infineon Technologies Office.
Infineon Technologies components may be used in life-support devices or systems only with the express written
approval of Infineon Technologies, if a failure of such components can reasonably be expected to cause the failure
of that life-support device or system or to affect the safety or effectiveness of that device or system. Life support
devices or systems are intended to be implanted in the human body or to support and/or maintain and sustain
and/or protect human life. If they fail, it is reasonable to assume that the health of the user or other persons may
be endangered.
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
CoolSETTM
Revision History:
2007-10
Previous Version:
2007-05
Page
Subjects (major changes since last revision)
Page 11
2007-10 Update Schematics (Figure 2 and Figure 3)
V1.1
V1.0
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Application Note
3
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Table of Contents
Page
1
Abstract ........................................................................................................................................................5
2
Introduction..................................................................................................................................................6
3
Application ...................................................................................................................................................7
4
CoolSET™ Third Generation of System ICs.............................................................................................8
5
TLE4305 Constant Current Regulator .......................................................................................................9
6
Power Supply Specification .....................................................................................................................10
7
Schematics.................................................................................................................................................11
8
PCB Layout ................................................................................................................................................12
9
9.1
9.2
9.3
9.4
9.5
9.6
9.7
9.8
Board Description .....................................................................................................................................13
Start Up .......................................................................................................................................................13
Operation Mode...........................................................................................................................................13
Snubber Network.........................................................................................................................................13
Soft Start......................................................................................................................................................13
Feedback Network (optional) ......................................................................................................................13
Peak Power Limitation (Limitation of the Primary Current) .........................................................................13
Output Section and Current Regulation via TLE4305G ..............................................................................14
Alternating Load during Operation ..............................................................................................................14
10
Conclusion .................................................................................................................................................15
11
Bill of Material ............................................................................................................................................16
12
Transformer Construction Documentation ............................................................................................17
13
Performance Data......................................................................................................................................18
13.1 Efficiency .....................................................................................................................................................18
13.2 Output Current Regulation ..........................................................................................................................19
14
14.1
14.2
14.3
Waveforms and Scope Plots ....................................................................................................................20
Start Up @ Low and High Line....................................................................................................................20
Drain Source Voltage and Current ..............................................................................................................22
Regulation Characteristic ............................................................................................................................23
15
References .................................................................................................................................................24
Application Note
4
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Abstract
1
Abstract
High brightness LEDs are becoming more popular in replacing conventional incandescent lamps in terms of
efficiency, reliability and space requirement. Moreover, the field of emergency lighting and advertising has been
made available to LED lighting. In using an integrated off line switching regulator like CoolSETTM in combination
with the current regulator TLE4305, a low cost and high efficient LED driver for multiple LEDs has been
developed to drive the LEDs from an extended wide line input voltage.
Application Note
5
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Introduction
2
Introduction
This document introduces the isolated offline coφnstant current high line LED driver based on the CoolSET™
family. The paper contains a list of features, power supply specification, schematic, bill of material and the
transformer construction documentation. Typical operating characteristics are presented at the rear of this report
and consist of performance curves and scope waveforms.
Introduction
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Application
3
Application
The Infineon Technologies AG proposes an isolated off line switch mode power supply (SMPS, see Figure 1) for
a LED cluster used for wide line input voltage applications from VACIN = 90 V up to 270 V in flyback topology.
The application is fully protected against an open loop gain (OLP), short circuit (OCP), over temperature (OTP),
over voltage at the VCC stage (OVP), under voltage (UVLO) and a highly accurate power limiting in case of over
load via Propagation Delay Compensation™ (patented by Infineon Technologies AG) in the whole line input
voltage range. All protection features are using the auto restart mode. Optional, the application is able to drive
the LEDs in a continuous load (Figure 2), or for alternating load, in that case, the LEDs are protected against
surge currents during alternating loads (see Figure 3). The driver application uses the Infineon jitter system
IC CoolSETTM F3 as PWM current mode controller with integrated MOSFET (CoolMOSTM) and the TLE4305G
as a current regulator on the secondary side. The application is designed to drive one 350 mA high brightness
LED or optional a series connection of up to 6 high brightness LEDs (350 mA) in a high efficiency.
Bottom View
Figure 1
LED-ICE3B0365JG Demoboard
TOP View
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
CoolSET™ Third Generation of System ICs
4
CoolSET™ Third Generation of System ICs
The CoolSETTM family is a smart hybrid power device combines the superior technology of the high voltage
MOSFET CoolMOSTM and a PWM current mode control IC. It is designed for switched mode power supplies
using a lower external component count - standard applications require only 7 external components to drive the
CoolSETTM. In order to increase the reliability, the integrated control circuit offers the benefit of enhanced
protection features all with auto restart (hiccup mode), an active burst mode for extreme low standby power, a
high voltage start up cell, a programmable soft start and blanking window function and a frequency jittering to
reduces EMI. The lowest area specific RDS(ON), a high avalanche ruggedness and the low switching losses of the
CoolMOSTM increase the efficiency and improves the standby power. The integrated Propagation Delay
CompensationTM (patented by Infineon Technologies) results a highly accurate power limiting in the whole line
input voltage range – optimized design for a global application.
Table 1
List of Integrated CoolSETTM Features
Feature List
CoolSETTM Device ICE3B0365JG with 67 kHz Working Frequency
650V 1 CoolMOSTM with implemented Start Up Cell
Integrated active Burst Mode Function with immediate Response of Load Jumps
Programmable Over Current Blanking Window for short Term Over Current
Programmable Soft Start
Integrated Frequency Jitter to improve the EMI Behavior
Integrated Over Load Protection (OLP) with auto restart
Integrated Over Current Protection (OCP) with auto restart
Integrated Over Temperature (OTP) Shut Down with auto restart
Integrated Open Loop Protection (OLP) with auto restart
Integrated Under Voltage Lock Out (UVLO) with auto restart
Integrated Propagation Delay CompensationTM and Leading Edge Blanking
External Current Sense for highly accurate Power Limiting
PDSO16/12 SMD Package with extended Creepage Distance
1
VDSBR at Tj = 110°C
Application Note
8
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
TLE4305 Constant Current Regulator
5
TLE4305 Constant Current Regulator
The TLE4305G is specifically designed to control the output voltage and the output current of a SMPS.
Independent compensation networks for the voltage and the current loop can be realized by external circuitry.
The device contains a high accuracy bandgap reference voltage, two operational transconductance amplifiers
(OTA), an optocoupler driver output stage and a high-voltage bias circuit. The device is based on Infineons
double isolated power line technology DOPL which allows producing high precision bipolar voltage regulators
with breakdown voltages up to 45 V. The efficiency increases furthermore due to the very low voltage drop
(only 200 mV) at the shunt resistors R28 and R29 of the TLE4305G.
Application Note
9
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Power Supply Specification
6
Power Supply Specification
Table 2
Power Supply Specification
Description
Symbol
Min.
Typ.
Max.
Units
115/230
270
VAC
380
VDC
23.6
VDC
Input Section
AC Input Voltage
(f =16 – 400 Hz)
VACIN
90
DC Input Voltage
VDCIN
120
Output Section
Output Voltage @ no Load
VOUT
Output Voltage Conditions
VOUT
4.0
16.7
22.5
VDC
Output Current
IOUT
340
340
340
mADC
Output Power Nominal
POUT
1.4
5.7
7.8
W
Efficiency (90 VAC)
η
77
86
87
%
Efficiency (270 VAC)
η
63
84
85
%
Environmental
Ambient Temperature
TA
25
°C
Thermal Consideration (Temperature Increase @ nom Load and VACIN = 90V)
Transformer
20
°C
CoolSETTM
20
°C
TLE4305
20
°C
Output Diode
50
°C
LED LA W57B
70
°C
Output Capacitors
20
°C
Application Note
10
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Schematics
7
Schematics
Figure 2
Power Supply Schematic for Continuous Load (Standard)
Figure 3
Power Supply Schematic for Alternating Load
Application Note
11
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
PCB Layout
8
PCB Layout
24 V / 350 mA – LED-Demoboard
Infineon
technologies
Figure 4
Power Supply PCB Layout
Application Note
12
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Board Description
9
Board Description
The SMPS for a LED cluster is an isolated off line discontinuous current mode (DCM) application in flyback
mode using ICE3B0365JG – the smallest system IC from the CoolSETTM - F3 family. The circuit diagram in
Figure 2 (standard continuous load) and Figure 3 (for alternating load) details a 24 V / 350 mA power supply
which operates from an extended AC line input voltage range from 90 VAC to 270 VAC, suitable for applications
requiring either an open frame supply or an enclosed application. By replacing R41 with high brightness LEDs,
the application is able to drive 1 white and in additional 6 red LEDs. The efficiency of the application is above
85% - the TLE4305G regulates the current and a constant no load voltage.
9.1
Start Up
After switch on the AC line input voltage, the integrated start up cell (depletion MOSFET on the CoolMOSTM
inside CoolSETTM) charges the chip supply stage up to VCC = 18 V, the controller starts working. In that moment,
the start up cell shuts off and is inactive during operation mode in order to increase the efficiency.
9.2
Operation Mode
The IC will be supplied from the auxiliary winding N2 in forward mode, R2 and the rectifier diode D6. C13 and C14
are taking care of a sufficient VCC voltage during different operation modes from no load to nominal load
operation. The chip supply voltage (VCC) of the CoolSETTM follows the AC line input voltage from 0 V up to
22.5 VDC. In case of a higher VCC than 19 V, the network Q1, R3 and D7 clamps the chip supply voltage at
VDC = 19 V in order to protect the chip supply stage of CoolSETTM against over voltage.
9.3
Snubber Network
A RCD snubber (R1, C12 and D5) clamps the drain source voltage below 600 V in order to prevent an avalanche
breakdown of the MOSFET.
9.4
Soft Start
For a soft start during a start up or an auto restart after failure case, the soft start capacitor C16 avoids stress on
the MOSFET and the diode and prevents audible noise during start up.
9.5
Feedback Network (optional)
Optional, a low pass filter (C17 and R5) can be set to eliminate disturbances of the signal of the optocoupler (IC2)
at the feedback PIN 3 of the CoolSETTM.
9.6
Peak Power Limitation (Limitation of the Primary Current)
R4 adjusts the primary current and furthermore, the shunt resistor limits the maximum power in case of over load
during the whole AC input voltage range (integrated Propagation Delay Compensation, patented by Infineon
Technologies AG). The accuracy of the power limitation depends only on the tolerance of the
shunt (R4).
Application Note
13
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Board Description
9.7
Output Section and Current Regulation via TLE4305G
The voltage on the secondary side is rectified via a fast rectifier diode D21 with a low forward voltage. A low
ESR Capacitor C24 buffers energy for the output stage. The output voltage is set by the voltage divider R24 and
R25 to VOUT = 24 VDCmax. The chip supply voltage of the TLE4305G is rectified via diode D22. R21 (optional) and
capacitor C21 perform energy buffering for the chip supply stage at PIN VS of the TLE4305G. C22 and C23
eliminate glitches on the chip supply stage. R22 and D23 ensure stable operation during no load condition
(POUT = 0 W). Due to the wide output voltage range from 0 V up to 22.5 VDC, the chip supply voltage (VS) of the
TLE4305G follows the line input voltage. In case of a higher VCC than 12 V, the network Q21, R23 and D24
clamps the chip supply voltage at VDC = 12 V in order to protect the chip supply stage of TLE4305G against over
voltage. R26, C25 and R27, C26 are compensation networks for the output voltage and current. The current is
sensed via shunt resistors R28 and R29.
9.8
Alternating Load during Operation
Note: This network is only needed in case of alternating load operation e.g. changing LEDs during operation
mode and not for continuous load operations. In case of alternating load, a discharge current from the
output capacitor C24 is present. This current causes a surge current peak through the LEDs. This might
results a damage or a destruction of the LEDs. To prevent a destruction of the LEDs, an optional surge
current compensation network (R30, Q22 and Q23 in Figure 3) can be implemented to limit the discharging
current from the capacitor C24.
Application Note
14
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Conclusion
10
Conclusion
The Infineon Technologies off line LED SMPS solution - using the Infineon current mode control system IC
CoolSET™ with integrated frequency jitter and TLE4305G - was designed to give maximum protection against
electrical shock from the high line input voltage, application reliability, improved EMI behavior and protects the
LED against surge current during load jumps. The compact design is able to be used worldwide without any
adjustments, has a high efficiency at a different numbers of LEDs, a highly accurate output current control and a
very low standby power rating during no load condition (POUT = 0 W). The high integration of both Infineon
devices enables a minimum of external components with a maximum of protection features for a cost saving
SMPS design.
Application Note
15
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Bill of Material
11
Bill of Material
350 mA / 24 V LED-SMPS with peak current limitation
AC Input 90 VAC … 270 VAC
Component
Value
Package
Component
Value
Package
K1
C21
10 µF / 40 V
RM2.5
K2
C22
100 nF / 50 V
1206
F1
Fuse 1A fast
Microfuse
C23
100 nF / 50 V
RM5
IC1
ICE3B0365JG
P-DSO-16/12
C24
100 µF / 35 V
RM5 low ESR
IC2
SFH617A-3
C25
33 nF / 50 V
1206
IC3
TLE4305G
P-DSO-8
C26
33 nF / 50 V
1206
BR1
B250S
SMD
L1
2.2 mH / 0.5 A
SU9V
D5
MURS 160
MELF-B
TR2
Air Gap 0.2 mm
EF16
D6
ES1D
Mini-MELF
N1 = 116 turns
D7
ZMM 20
Mini-MELF
N2 = 13 turns
D21
ES1D
MELF-B
N3 = 25 turns
D22
ES1D
Mini-MELF
N4 = 12 turns
D23
LL4148
Mini-MELF
R1
100 kΩ
axial
D24
ZMM 12
1206
R2
4.7 Ω
1206
D41
LA W57B
R3
10 kΩ
1206
D51
LW5SG
R4
2.7 Ω
1206
Q1
BC846B
SOT23
R5
22 Ω
axial
Q21
BC846B
SOT23
R21
4.7 Ω
1206
Q22
BC817
SOT23
R22
4.7 kΩ
axial
Q23
BSP 320S
SOT223
R23
10 kΩ
1206
C1
100 nF / 250 VAC-X2 RM15
R24
33 kΩ
1206
C5
1 nF / 250 VAC-Y1
RM15
R25
3.9 kΩ
1206
C11
10 µF / 400 V
RM5
R26
22 kΩ
1206
C12
1 nF / 400 V
RM5
R27
22 kΩ
1206
C13
4.7 µF / 25 V
RM2.5
R28
1.2 Ω
1206
C14
10 µF / 40 V
RM2.5
R29
1.2 Ω
1206
C15
100 nF / 50 V
1206
R30
15 kΩ
1206
C16
470 nF / 50 V
1206
R41
39 Ω / 10 W
axial
C17
2.2 nF / 50 V
1206
S1
N2F4PCA
Switch
Application Note
16
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Transformer Construction Documentation
12
Transformer Construction Documentation
9W LED Flyback Transformator
24V/350mA-Demoboard
Core: EF16/8/5
Material: N67
Coil Former: horizontal Inductivity: 1,75mH
Pin 4
Pin 5
Total Air Gap: 0,2mm
Peak Current: 0,4A
Aux
Sec 2
Pin 7
Pin 6
Pin 9
Pin 10
Sec 1 = 9Turns
Sec 1 = 16Turns
Pin 2
Prim
Pin 1
Center leg
means one layer Makrofol
Primary winding
Secondary winding 1
Secondary winding 2
Auxiliary winding
Application Note
116 turns 0,18 mm ∅
25 turns 0,35 mm ∅ TEX-E wire
12 turns 0,35 mm ∅ TEX-E wire
13 turns 0,18 mm ∅ spread
5
6
4
1
7
10
2
9
Bottom View:
Pin
Pin
Pin
Pin
Pin
17
5
4
3
2
1
•
∙
∙
∙
∙
•
∙
∙
∙
∙
Pin
Pin
Pin
Pin
Pin
6
7
8
9
10
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Performance Data
13
Performance Data
13.1
Efficiency
Efficiency vs. Pout
80
70
Efficiency [%]
60
50
40
30
20
10
0
0
1
2
3
4
5
6
7
8
Pout [W]
Vacin = 90V
Figure 5
Vacin = 270V
Efficiency versus Output Power
Figure 5 shows the efficiency (y-axis) versus output power (x-axis) of the LED SMPS at low line input voltage
VACIN = 90 V and high line input voltage VACIN = 270 V for different numbers of LEDs.
Application Note
18
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Performance Data
13.2
Output Current Regulation
Output Current versus Output Voltage
0,4
0,35
Output Current [A]
0,3
0,25
0,2
0,15
0,1
0,05
0
0
2
4
6
8
10
12
14
16
18
20
22
24
26
Output Voltage [V]
Output Current
Figure 6
Controlled Output Current versus Output Voltage
Figure 6 shows the current regulation characteristic of the output stage. The output voltage (x-axis) rises with
increasing load from POUTmin until maximum load (1 white and add. 6 red high brightness LEDs). While
exceeding maximum load (respective maximum output voltage) the TLE4305G decreases the current (y-axis)
down to zero and holds the output voltage stable at the maximum level of VOUT = 23.6 V.
Application Note
19
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Waveforms and Scope Plots
14
Waveforms and Scope Plots
14.1
Start Up @ Low and High Line
Figure 7 and Figure 8 are showing a typical start up from plug in the AC line input voltage till working mode. The
chip supply voltage VCC (Ch1) will be charged up via the implemented start up cell to the VCCON threshold
@ typ. 18 V. If the chip supply voltage exceeds this threshold, the start up cell is inactive. Now, the control IC
starts working and switches the gate drive on. In the soft start phase - the soft start voltage (Ch3) rises from 1 V
up to 3 V to limit the primary current via duty cycle limitation. If the soft start voltage reach the operation
threshold at typ. 3.2 – 3.6 V (sawtooth wave form) and the output voltage (Ch4) reaches the working level, the
feedback voltage (Ch2) decreases from its reference voltage down to the operation level dependent from the
load at the output.
Application Note
20
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Waveforms and Scope Plots
Start UP: VACIN = 90 V (High Resolution Mode)
Ch1: VCC (Chip Supply Voltage PIN 11 to GND PIN 12)
Ch2: VFB (Feedback Voltage PIN 31 to GND PIN 12)
Ch3: VSS (Softstart Voltage PIN 2 to GND PIN 12)
Ch4: VOUT (Output Voltage C24 to TLE GND)
Figure 7
Startup @ Low and High AC Line Input Voltage and Nominal Load
Start UP: VACIN = 90 V (High Resolution Mode)
Ch1: VCC (Chip Supply Voltage PIN 11 to GND PIN 12)
Ch2: VFB (Feedback Voltage PIN 31 to GND PIN 12)
Ch3: VSS (Softstart Voltage PIN 2 to GND PIN 12)
Ch4: VOUT (Output Voltage C24 to TLE GND)
Figure 8
Start UP: VACIN = 270 V (High Resolution Mode)
Ch1: VCC (Chip Supply Voltage PIN 11 to GND PIN 12)
Ch2: VFB (Feedback Voltage PIN 31 to GND PIN 12)
Ch3: VSS (Softstart Voltage PIN 2 to GND PIN 12)
Ch4: VOUT (Output Voltage C24 to TLE GND)
Start UP: VACIN = 270 V (High Resolution Mode)
Ch1: VCC (Chip Supply Voltage PIN 11 to GND PIN 12)
Ch2: VFB (Feedback Voltage PIN 31 to GND PIN 12)
Ch3: VSS (Softstart Voltage PIN 2 to GND PIN 12)
Ch4: VOUT (Output Voltage C24 to TLE GND)
Startup @ Low and High AC Line Input Voltage and light Load
Application Note
21
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Waveforms and Scope Plots
14.2
Drain Source Voltage and Current
RUN Mode: VACIN = 90 V (High Res. Mode) @ nom. Load
Ch1: VSense (Sense Voltage @ CoolSET PIN 4 to GND PIN 12)
Ch2: VOUT (Output Voltage @ C24 to TLE GND PIN 5)
Ch3: IOUT (Output Current @ through Golden Dragon Diode)
Ch4: VDS (Drain Source Voltage @ Transformer PIN 2)
Figure 9
Drain Source Voltage and Current during Normal Operation @ nom. Load
RUN Mode: VACIN = 90 V (High Res. Mode) @ light Load
Ch1: VSense (Sense Voltage @ CoolSET PIN 4 to GND PIN 12)
Ch2: VOUT (Output Voltage @ C24 to TLE GND PIN 5)
Ch3: IOUT (Output Current @ through Golden Dragon Diode)
Ch4: VDS (Drain Source Voltage @ Transformer PIN 2)
Figure 10
RUN Mode: VACIN = 270 V (High Res. Mode) @ nom. Load
Ch1: VSense (Sense Voltage @ CoolSET PIN 4 to GND PIN 12)
Ch2: VOUT (Output Voltage @ C24 to TLE GND PIN 5)
Ch3: IOUT (Output Current @ through Golden Dragon Diode)
Ch4: VDS (Drain Source Voltage @ Transformer PIN 2)
RUN Mode: VACIN = 270 V (High Res. Mode) @ light Load
Ch1: VSense (Sense Voltage @ CoolSET PIN 4 to GND PIN 12)
Ch2: VOUT (Output Voltage @ C24 to TLE GND PIN 5)
Ch3: IOUT (Output Current @ through Golden Dragon Diode)
Ch4: VDS (Drain Source Voltage @ Transformer PIN 2)
Drain Source Voltage and Current during Normal Operation @ light Load
Application Note
22
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
Waveforms and Scope Plots
14.3
Regulation Characteristic
Note: (optional, not needed for continuous load operation):
In case of alternating load, a discharge current from the output capacitor C24 is present. This current
causes a surge current peak (Ch4) through the LEDs. This surge current will be compensated with the
network (R30, Q22 and Q23) in order to protect the LEDs. Figure 1111 shows regulation characteristic of
this network regarding the surge current through the LEDs in two states: alternating load from nominal and
no load into light load condition with out shut off of the application (feedback Ch2 and soft start voltage
Ch3 are in its working levels).
Load Jump from nominal Load to light Load
Ch1: VOUT (Output Voltage @ C24 to TEL GND PIN 5)
Ch2: VFB (Feedback Voltage @ CoolSET PIN 3 to GND PIN 12)
Ch3: VSoft Start (Soft Start Voltage @ CoolSET PIN 2 to GND PIN 12)
Ch4: IOUT (Output Current @ through Diodes Golden Dragon)
Figure 11
Load Jump from nominal Load to light Load
Ch1: VOUT (Output Voltage @ C24 to TEL GND PIN 5)
Ch2: VFB (Feedback Voltage @ CoolSET PIN 3 to GND PIN 12)
Ch3: VSoft Start (Soft Start Voltage @ CoolSET PIN 2 to GND PIN 12)
Ch4: IOUT (Output Current @ through Diodes Golden Dragon)
Load Jump Behavior
Application Note
23
V1.1, 2007-10
CoolSETTM
LED Demoboard using ICE3B0365JG on Board
References
15
References
[1]
ICE2AXXX for OFF-Line Switch Mode Power Supplies
Application Note, Infineon Technologies
[2]
CoolSETTM – III
Off-line SMPS Current Mode Controller with High Voltage CoolMOSTM on Board
Datasheet, Infineon Technologies
[3]
Application Note
24
V1.1, 2007-10
www.infineon.com
Published by Infineon Technologies AG
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