20W 5V Evaluation Board using ICE3BR1765JZ

Application Note, V1.0, Dec 2011
AN-EVAL3BR1765JZ
20W 5V SMPS Evaluation Board with
CoolSET® F3R ICE3BR1765JZ
Power Management & Supply
N e v e r
s t o p
t h i n k i n g .
Published by
Infineon Technologies AG
81726 Munich, Germany
© 2011 Infineon Technologies AG
All Rights Reserved.
Legal Disclaimer
The information given in this document shall in no event be regarded as a guarantee of
conditions or characteristics. With respect to any examples or hints given herein, any typical
values stated herein and/or any information regarding the application of the device,
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.
Information
For further information on technology, delivery terms and conditions and prices, please
contact the nearest Infineon Technologies Office (www.infineon.com).
Warnings
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on the types in question, please contact the nearest Infineon Technologies Office.
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the express written approval of Infineon Technologies, if a failure of such components can
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20W 5V Demo board using ICE3BR1765JZ
Revision History:
Previous Version:
Page
2011-12
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Subjects (major changes since last revision)
20W 5V SMPS Evaluation Board with CoolSET® F3R ICE3BR1765JZ:
License to Infineon Technologies Asia Pacific Pte Ltd
Kyaw Zin Min
Kok Siu Kam Eric
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V1.0
AN-PS0058
20W 5V Demo board using ICE3BR1765JZ
Table of Contents
Page
1 Abstract .......................................................................................................................................... 5 2 Evaluation board ........................................................................................................................... 5 3 List of features .............................................................................................................................. 6 4 Technical specifications............................................................................................................... 6 5 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11 5.12 5.13 Circuit description ........................................................................................................................ 7 Introduction...................................................................................................................................... 7 Line input ......................................................................................................................................... 7 Start up ............................................................................................................................................ 7 Operation mode .............................................................................................................................. 7 Soft start .......................................................................................................................................... 7 RCD clamper circuit ........................................................................................................................ 7 Peak current control of primary current........................................................................................... 7 Output stage .................................................................................................................................... 8 Feedback and regulation................................................................................................................. 8 Blanking window for load jump........................................................................................................ 8 Active burst mode ........................................................................................................................... 8 Jitter mode....................................................................................................................................... 8 Protection modes ............................................................................................................................ 9 6 Circuit diagram ............................................................................................................................ 10 7 7.1 7.2 PCB layout ................................................................................................................................... 12 Top side......................................................................................................................................... 12 Bottom side ................................................................................................................................... 12 8 Component list ............................................................................................................................ 13 9 Transformer construction .......................................................................................................... 14 10 10.1 10.2 10.3 10.4 10.5 10.6 10.7 10.8 Test results .................................................................................................................................. 15 Efficiency ....................................................................................................................................... 15 Input standby power ...................................................................................................................... 16 Line regulation ............................................................................................................................... 17 Load regulation ............................................................................................................................. 17 Maximum input power ................................................................................................................... 18 ESD test ........................................................................................................................................ 18 Lightning surge test ....................................................................................................................... 18 Conducted EMI ............................................................................................................................. 19 11 11.1 11.2 11.3 11.4 11.5 11.6 11.7 11.8 11.9 11.10 11.11 11.12 11.13 Waveforms and scope plots ...................................................................................................... 21 Start up at low and high AC line input voltage and maximum load............................................... 21 Soft start at low and high AC line input voltage and maximum load ............................................. 21 Frequency jittering ......................................................................................................................... 22 Drain to source voltage and current @ maximum load................................................................. 22 Load transient response ( Dynamic load from 10% to 100%) ...................................................... 23 Output ripple voltage at maximum load ........................................................................................23 Output ripple voltage during burst mode at 1 W load ................................................................... 24 Entering active burst mode ........................................................................................................... 24 Vcc overvoltage protection ............................................................................................................ 25 Over load protection (built-in + extended blanking time) .............................................................. 25 Open loop protection ..................................................................................................................... 26 VCC under voltage/Short optocoupler protection ........................................................................... 26 Auto restart enable ........................................................................................................................ 27 12 12.1 Appendix ...................................................................................................................................... 28 Slope compensation for CCM operation ....................................................................................... 28 13 References ................................................................................................................................... 28 Application Note
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1
Abstract
This document is an engineering report of a universal input 5V 20W off-line flyback converter power supply
utilizing IFX F3R CoolSET® ICE3BR1765JZ. The application demo board is operated in Discontinuous
Conduction Mode (DCM) and is running at 65 kHz switching frequency. It has a one output voltage with
secondary side control regulation. It is especially suitable for small power supply such as DVD player, set-top
box, game console, charger and auxiliary power of high power system, etc. The ICE3BR1765JZ is the latest
version of the CoolSET®. Besides having the basic features of the F3R CoolSET® such as Active Burst
Mode, propagation delay compensation, soft gate drive, auto restart protection for serious fault (Vcc over
voltage protection, Vcc under voltage protection, over temperature, over-load, open loop and short optocoupler), it also has the BiCMOS technology design, built-in soft start time, built-in and extendable blanking
time, frequency jitter feature with built-in jitter period and external auto-restart enable, etc. The particular
features needs to be stressed are the best in class low standby power and the good EMI performance.
2
Evaluation board
Figure 1 – EVAL3BR1765JZ
This document contains the list of features, the power supply specification, schematic, bill of material and the
transformer construction documentation. Typical operating characteristics such as performance curve and
scope waveforms are showed at the rear of the report.
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List of features
650V avalanche rugged CoolMOS® with built-in Startup Cell
Active Burst Mode for lowest Standby Power
Fast load jump response in Active Burst Mode
65 kHz internally fixed switching frequency
Auto Restart Protection Mode for Overload, Open Loop, Vcc Undervoltage, Overtemperature & Vcc
Overvoltage
Built-in Soft Start
Built-in blanking window with extendable blanking time for short duration high current
External auto-restart enable pin
Max Duty Cycle 75%
Overall tolerance of Current Limiting < ±5%
Internal PWM Leading Edge Blanking
BiCMOS technology provides wide VCC range
Built-in Frequency jitter feature and soft driving for low EMI
4
Technical specifications
Input voltage
85VAC~265VAC
Input frequency
60Hz, 50Hz
Input Standby Power
< 50mW at no load
Output voltage
5V +/- 1%
Output current
4A
Output power
20W
Active mode average efficiency(25%,50%,75% & 100%load)
>79%
Output ripple voltage
< 50mVp-p
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5
Circuit description
5.1
Introduction
The EVAL3BR1765JZ demo board is a low cost off line flyback switch mode power supply ( SMPS ) using
the ICE3BR1765JZ integrated power IC from the CoolSET® -F3R family. The circuit, shown in Figure 2,
details a 5V, 20W power supply that operates from an AC line input voltage range of 85Vac to 265Vac,
suitable for applications in open frame supply or enclosed adapter.
5.2
Line input
The AC line input side comprises the input fuse F1 as over-current protection. The choke L11, X-capacitor
C11 and Y-capacitor C12 act as EMI suppressors. Optional surge absorber device SA1, SA2 and varistor
VAR can absorb high voltage stress during lightning surge test. A rectified DC voltage (120V ~ 374V) is
obtained through the bridge rectifier BR1 and the input bulk capacitor C13.
5.3
Start up
Since there is a built-in startup cell in the ICE3BR1765JZ, there is no need for external start up resistors. The
startup cell is connecting the drain pin of the IC. Once the voltage is built up at the Drain pin of the
ICE3BR1765JZ, the startup cell will charge up the Vcc capacitor C16 and C17. When the Vcc voltage
exceeds the UVLO at 18V, the IC starts up. Then the Vcc voltage is bootstrapped by the auxiliary winding to
sustain the operation.
5.4
Operation mode
During operation, the Vcc pin is supplied via a separate transformer winding with associated rectification D12
and buffering C16, C17. Resistor R12 is used for current limiting. In order not to exceed the maximum
voltage at Vcc pin, an external zener diode ZD11 and resistor R13 can be added.
5.5
Soft start
The Soft-Start is a built-in function and is set at 20ms.
5.6
RCD clamper circuit
While turns off the CoolMOS®, the clamper circuit R11, C15 and D11 absorbs the current caused by
transformer leakage inductance once the voltage exceeds clamp capacitor voltage. Finally drain-source
voltage of CoolMOS® is lower than maximum break down voltage of CoolMOS®.
5.7
Peak current control of primary current
The CoolMOS® drain source current is sensed via external shunt resistors R14 and R15 which determine the
tolerance of the current limit control. Since ICE3BR1765JZ is a current mode controller, it would have a
cycle-by-cycle primary current and feedback voltage control and can make sure the maximum power of the
converter is controlled in every switching cycle. Besides, the patented propagation delay compensation is
implemented to ensure the maximum input power can be controlled in an even tighter manner throughout the
wide range input voltage. The demo board shows approximately +/-2.07% (refer to Figure 12).
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5.8
Output stage
On the secondary side the power is coupled out by a schottky diode D21. The capacitor C22 provides energy
buffering following with the LC filter L21 and C23 to reduce the output voltage ripple considerably. Storage
capacitor C22 is selected to have an internal resistance as small as possible (ESR) to minimize the output
voltage ripple.
5.9
Feedback and regulation
The output voltage is controlled using a TL431 (IC21). This device incorporates the voltage reference as well
as the error amplifier and a driver stage. Compensation network C25, C26, R24, R25, R26, R27 and R28
constitutes the external circuitry of the error amplifier of IC21. This circuitry allows the feedback to be
precisely matched to dynamically varying load conditions and provides stable control. The maximum current
through the optocoupler diode and the voltage reference is set by using resistors R22 and R23. Optocoupler
IC12 is used for floating transmission of the control signal to the “Feedback” input via capacitor C18 of the
ICE3BR1765JZ control device. The optocoupler used meets DIN VDE 884 requirements for a wider
creepage distance.
5.10
Blanking window for load jump
In case of Load Jumps the Controller provides a Blanking Window before activating the Over Load Protection
and entering the Auto Restart Mode. The blanking time is built-in at 20ms. If a longer blanking time is
required, a capacitor, C19 can be added to BA pin to extend it. The extended time can be achieved by an
internal 13µA constant current at BA pin to charge C19 ( CBK =8.2nF) from 0.9V to 4.0V. Thus the overall
blanking time is the addition of 20ms and the extended time. The voltage at Feedback pin can rise above
4.3V without switching off due to over load protection within this blanking time frame. During the operation
the transferred power is limited to the maximum peak current defined by the value of the current sense
resistor, R14 and R15.
Tblanking = Basic + Extended = 20ms +
5.11
( 4.0 − 0.9) * CBK
= 20ms + 238461.5 * CBK = 21.95ms
IBK
Active burst mode
At light load condition, the SMPS enters into Active Burst Mode. At this start, the controller is always active
and thus the VCC must always be kept above the switch off threshold VCCoff ≥ 10.5V. During active burst
mode, the efficiency increases significantly and at the same time it supports low ripple on VOUT and fast
response on load jump. When the voltage level at FB falls below 1.35V, the internal blanking timer starts to
count. When it reaches the built-in 20ms blanking time, it will enter Active Burst Mode. The Blanking Window
is generated to avoid sudden entering of Burst Mode due to load jump.
During Active Burst Mode the current sense voltage limit is reduced from 1.03V to 0.34V so as to reduce the
conduction losses and audible noise. All the internal circuits are switched off except the reference and bias
voltages to reduce the total VCC current consumption to below 0.45mA. At burst mode, the FB voltage is
changing like a saw tooth between 3 and 3.5V. To leave Burst Mode, FB voltage must exceed 4V. It will
reset the Active Burst Mode and turn the SMPS into Normal Operating Mode. Maximum current can then be
provided to stabilize VOUT.
5.12
Jitter mode
The ICE3BR1765JZ has frequency jittering feature to reduce the EMI noise. The jitter frequency is internally
set at 65 kHz (+/- 2.6 kHz) and the jitter period is set at 4ms.
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5.13
Protection modes
Protection is one of the major factors to determine whether the system is safe and robust. Therefore
sufficient protection is necessary. ICE3BR1765JZ provides all the necessary protections to ensure the
system is operating safely. The protections include Vcc overvoltage, overtemperature, overload, open loop,
Vcc undervoltage, short optocoupler, etc. When those faults are found, the system will go into auto restart
which means the system will stop for a short period of time and restart again. If the fault persists, the system
will stop again. It is then until the fault is removed, the system resumes to normal operation. A list of
protections and the failure conditions are showed in the below table.
Protection function
Failure condition
Vcc Overvoltage
1. Vcc > 20.5V & FB > 4.0V & during soft start period
2. Vcc > 25.5V
Auto Restart
Overtemperature
(controller junction)
TJ > 130°C
Auto Restart
Overload / Open loop
VFB > 4.0V and VBA > 4.0V
(Blanking time counted from charging VBA from 0.9V to
4.0V )
Auto Restart
Vcc Undervoltage / Short
Optocoupler
Vcc < 10.5V
Auto Restart
Auto-restart enable
VBA < 0.33V
Auto Restart
Application Note
Protection Mode
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Circuit diagram
Figure 2 – 20W 5V ICE3BR1765JZ power supply schematic
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N.B. : In order to get the optimized performance of the CoolSET®, the grounding of the PCB layout must be
connected very carefully. From the circuit diagram above, it indicates that the grounding for the
CoolSET® can be split into several groups; signal ground, Vcc ground, Current sense resistor ground
and EMI return ground. All the split grounds should be connected to the bulk capacitor ground
separately.
•
Signal ground includes all small signal grounds connecting to the CoolSET® GND pin such as filter
capacitor ground, C17, C18, C19 and opto-coupler ground.
•
Vcc ground includes the Vcc capacitor ground, C16 and the auxiliary winding ground, pin 2 of the
power transformer.
•
Current Sense resistor ground includes current sense resistor R14 and R15.
•
EMI return ground includes Y capacitor, C12.
Application Note
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7
PCB layout
7.1
Top side
Figure 3 – Top side component legend
7.2
Bottom side
Figure 4 – Bottom side copper
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Component list
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
Designator
Component description
BR1
C11
C12
C13
C15
C16
C17
C18,C26
C19
C22
C23
C25
D11
D12
D21
F1
HS1
IC11
IC12
IC21
J1,J2,J3,J4,R16,
R27,L22
L N, +5V Com
L11
L21
PCB
R11
R12
R13
R14
R15
R22
R23
R24
R26, R28
TR1
ZD11
DF06M (600V,1A)
0.22uF/305V
2.2nF/250V,Y1
68uF/400V
2.2nF/400V
22uF/35V
0.1uF
1nF
8.2nF/50V
2200uF/10V
1000uF/10V
330nF/50V
UF4005(600V/1A)
1N485B (200V,0.2A)
STPS30L45CFP
1A/250V
Heat sink
ICE3BR1765JZ
SFH617A-3
TL431
Application Note
Part number
Manufacturer
B32922C3224K000
DE1E3KX222MA4BL01
B43504A5826M000
EPCOS
MURATA
EPCOS
RPER71H104K2K1A03B
RPE5C1H102J2K1A03B
MURATA
MURATA
UF4005
VISHAY
ICE3BR1765JZ
INFINEON
B82732R2901B30
EPCOS
B662061110T001
EPCOS
Jumper
Connector
2 x 27mH, 0.9A
1.5uH/6.3A
ICE3BR1765JZ(V0.4)20W 5V
39k (2W, 5%)
18R
47R
1R (0.5W,1%)
10R (0.5W,1%)
68R
1.2k
1k
10k
725µH (80:6:18),E20/10/6(N87)
22V/0.5W
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Transformer construction
Core and material: E20/10/6, N87(EPCOS)
Bobbin: Horizontal version
Primary Inductance, Lp=725μH(±5%), measured between pin 4 and pin 5(Gapped to Inductance)
Transformer structure:
5
6
3
4
7
2
1
Figure 5 – Transformer structure and top view of transformer complete
Wire size requirement:
Start
Application Note
Stop
No. of turns
Wire size
Layer
1
5
7
3
6
40
6
1XAWG#30
2XAWG#26
/2 Primary
Secondary
3
4
40
1XAWG#30
1
2
1
18
1XAWG#30
14
/2 Primary
Auxiliary
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Test results
10.1
Efficiency
Figure 6 – Efficiency Vs. AC line input voltage
Figure 7 – Efficiency Vs. output power @ low and high Line
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10.2
Input standby power
Figure 8 – Input standby power @ no load Vs. AC line input voltage ( measured by Yokogawa WT210
power meter - integration mode )
Figure 9 – Input standby power @ 0.5W, 1W, 2W & 3W Vs. AC line input voltage ( measured by
Yokogawa WT210 power meter - integration mode )
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10.3
Line regulation
Figure 10 – Line regulation Vout @ full load vs. AC line input voltage
10.4
Load regulation
Figure 11 – Load regulation Vout vs. output power
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10.5
Maximum input power
Figure 12 – Maximum input power ( before overload protection ) vs. AC line input voltage
10.6
ESD test
Pass (EN61000-4-2): 8kV for contact discharge (without surge absorber device)
Pass (EN61000-4-2): 14kV for contact discharge (with surge absorber device; SA1 & SA2 (DA38-102MB))
10.7
Lightning surge test
Pass (EN61000-4-5): 2kV for line to earth (without surge absorber device)
Pass (EN61000-4-5): 3kV for line to earth (with surge absorber device; SA1 & SA2 (DA38-102MB))
Application Note
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10.8
Conducted EMI
The conducted EMI was measured by Schaffner (SMR4503) and followed the test standard of EN55022
(CISPR 22) class B. The demo board was set up at maximum load (20W) with input voltage of 115Vac and
230Vac.
Figure 13 – Maximum load (20W) with 115 Vac (Line)
Figure 14 – Maximum load (20W) with 115 Vac (Neutral)
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Figure 15 – Maximum load (20W) with 230 Vac (Line)
Figure 16 – Maximum load (20W) with 230 Vac (Neutral)
Pass conducted EMI EN55022 (CISPR 22) class B with > 8dB margin.
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11
Waveforms and scope plots
All waveforms and scope plots were recorded with a LeCroy 6050 oscilloscope
11.1
Start up at low and high AC line input voltage and maximum load
561ms
561ms
Channel 1; C1 : Drain voltage (VDrain)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
Channel 1; C1 : Drain voltage (VDrain)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
Startup time = 561ms
Startup time = 561ms
Figure 17 – Startup @ 85Vac & max. load
Figure 18 – Startup @ 265Vac & max. load
11.2
Soft start at low and high AC line input voltage and maximum load
19.23ms
19.23ms
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
Soft Star time = 19.23ms(32 steps)
Soft Star time = 19.23ms(32 steps)
Figure 19 – Soft Start @ 85Vac & max. load
Figure 20– Soft Start @ 265Vac & max. load
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11.3
Frequency jittering
62.7kHz
62.7kHz
68.2kHz
68.2kHz
Channel 2; C2 : Drain to source voltage (VDS)
Channel 2; C2 : Drain to source voltage (VDS)
Frequency jittering from 62.7 kHz ~ 68.2kHz
Frequency jittering from 62.7 kHz ~ 68.2kHz
Figure 21 – Frequency jittering @ 85Vac and max.
load
Figure 22 – Frequency jittering @ 265Vac and
max. load
11.4
Drain to source voltage and current @ maximum load
Channel 1; C1 : Drain Current ( IDS )
Channel 2; C2 : Drain Source Voltage ( VDS )
Duty cycle = 44%, VDS_peak=265.4V
Figure 23 – Operation @ Vin = 85Vac and max.
load
Application Note
Channel 1; C1 : Drain Current ( IDS )
Channel 2; C2 : Drain Source Voltage ( VDS )
Duty cycle = 12.5% VDS_peak=531V
Figure 24 – Operation @ Vin = 265Vac and max.
load
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11.5
Load transient response ( Dynamic load from 10% to 100%)
Channel 1; C1 : Output Current ( Io )
Channel 2; C2 : Output ripple Voltage ( Vo )
Vripple_pk_pk=262mV (Load change from10% to
100%,100Hz,0.4A/μS slew rate)
Probe terminal end with decoupling capacitor of
0.1uF(ceramic) & 1uF(Electrolytic), 20MHz filter
Figure 25 – Load transient response @ 85Vac
11.6
Channel 1; C1 : Output Current ( Io )
Channel 2; C2 : Output ripple Voltage ( Vo )
Vripple_pk_pk=266mV (Load change from10% to
100%,100Hz,0.4A/μS slew rate)
Probe terminal end with decoupling capacitor of
0.1uF(ceramic) & 1uF(Electrolytic), 20MHz filter
Figure 26 – Load transient response @ 265Vac
Output ripple voltage at maximum load
Channel 2; C2 : Output Ripple Voltage ( Vo_ripple )
Channel 2; C2 : Output Ripple Voltage ( Vo_ripple )
Vripple_pk_pk=15mV
Probe terminal end with decoupling capacitor of
0.1uF(ceramic) & 1uF(Electrolytic), 20MHz filter
Figure 27 – AC output ripple @ Vin=85Vac and
max. load
Vripple_pk_pk=17mV
Probe terminal end with decoupling capacitor of
0.1uF(ceramic) & 1uF(Electrolytic), 20MHz filter
Figure 28 – AC output ripple @ Vin=265Vac and
max. load
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11.7
Output ripple voltage during burst mode at 1 W load
Channel 1; C1 : Output ripple voltage (Vo)
Vripple_pk_pk=22mV
Probe terminal end with decoupling capacitor
0.1uF(ceramic) & 1uF(Electrolytic), 20MHz filter
Channel 1; C1 : Output ripple voltage (Vo)
Vripple_pk_pk = 23mV
Probe terminal end with decoupling capacitor of
0.1uF(ceramic) & 1uF(Electrolytic), 20MHz filter
of
Figure 29 – AC output ripple @ 85Vac and 1W load
11.8
Figure 30 – AC output ripple @ 265Vac and 1W
load
Entering active burst mode
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
Blanking time to enter burst mode : 19ms (load step
down from 4A to 0.2A)
Figure 31 – Active burst mode @ 85Vac
Application Note
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
Blanking time to enter burst mode : 19ms (load step
down from 4A to 0.2A)
Figure 32 – Active burst mode @ Vin=265Vac
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11.9
Vcc overvoltage protection
VCC OVP2
VCC OVP1
VCC OVP2
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
VCC OVP2 first & follows VCC OVP1 (R28
disconnected during system operating with no load)
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
VCC OVP2 first & follows VCC OVP1 (R28
disconnected during system operating with no
load)
Figure 34 – Vcc overvoltage protection @ 265Vac
Figure 33 – Vcc overvoltage protection @ 85Vac
11.10
VCC OVP1
Over load protection (built-in + extended blanking time)
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
Over load protection with 21.9ms(20+1.9) blanking
time (output load change from 4A to 5.5A,
C19=10nF)
Figure 37 – Over load protection with
built-in+extended blanking time @ 85Vac
Application Note
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
Over load protection with 21.9ms(20+1.9) blanking
time (output load change from 4A to 5.5A,
C19=10nF)
Figure 38 – Over load protection with
built-in+extended blanking time @ 265Vac
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20W 5V Demo board using ICE3BR1765JZ
11.11
Open loop protection
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
Open loop protection (R28 disconnected during
system operation at max. load) – over load
protection
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
Open loop protection (R28 disconnected during
system operation at max. load) – over load
protection
Figure 39 – Open loop protection @ 85Vac
Figure 40 – Open loop protection @ 265Vac
11.12
VCC under voltage/Short optocoupler protection
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
VCC under voltage/short optocoupler protection
(short the transistor of optocoupler during system
operating @ full load)
VCC under voltage/short optocoupler protection
(short the transistor of optocoupler during system
operating @ full load)
Figure 41 – Vcc under voltage/short optocoupler
protection @ 85Vac
Figure 42 – Vcc under voltage/short optocoupler
protection @ 265Vac
Application Note
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20W 5V Demo board using ICE3BR1765JZ
11.13
Auto restart enable
Exit autorestart
Exit autorestart
Enter autorestart
Enter autorestart
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
Channel 1; C1 : Current sense voltage (VCS)
Channel 2; C2 : Supply voltage (VCC)
Channel 3; C3 : Feedback voltage (VFB)
Channel 4; C4 : BA voltage (VBA)
External autoreatart enable (short BA pin to Gnd by
10Ω resistor & open)
External autorestart enable (short BA pin to Gnd by
10Ω resistor & open)
Figure 43 – External protection enable @ 85Vac
Figure 44– External protection enable @ 265Vac
Application Note
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20W 5V Demo board using ICE3BR1765JZ
12
Appendix
12.1
Slope compensation for CCM operation
This demo board is designed in Discontinuous Conduction Mode ( DCM ) operation. If the application is
designed in Continuous Conduction Mode ( CCM ) operation where the maximum duty cycle exceeds the
50% threshold, it needs to add the slope compensation network. Otherwise, the circuitry will be unstable. In
this case, three more components ( 2 ceramic capacitors C17 / C18 and one resistor R19) is needed to add
as shown in the circuit diagram below.
Figure 45 – Circuit diagram switch mode power supply with slope compensation
More information regarding how to calculate the additional components, see application note
AN_SMPS_ICE2xXXX – available on the internet: www.infineon.com (directory : Home > Power
Semiconductors > Integrated Power ICs > CoolSET®F2)
13
References
[1]
Infineon Technologies, Datasheet “CoolSET® -F3R ICE3BR1765JZ Off-Line SMPS Current Mode
Controller with Integrated 650V CoolMOS® and Startup cell ( frequency jitter Mode ) in Dip-7”
[2]
Kyaw Zin Min, Kok Siu Kam Eric, Infineon Technologies, Application Note “CoolSET®-F3R (DIP-8, DIP7 & DSO-16/12) new Jitter version Design Guide”
[3]
Harald Zoellinger, Rainer Kling, Infineon Technologies, Application Note “AN-SMPS-ICE2xXXX-1,
CoolSET®. ICE2xXXXX for Off-Line Switching Mode Power supply (SMPS )”
Application Note
28
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