Demoboard DVD Application 30W

Multioutput 30W Evaluation Board
for DVD SMPS with ICE2A265
Junyang Luo, Ming Lik Yew and Meng Kiat Jeoh
Infineon Technologies Asia Pacific Pte. Ltd.
168 Kallang Way,
Singapore 349253
Email: [email protected], [email protected], and
[email protected]
The board described here was designed as a typical power supply in flyback converter topology with
multi output voltage and secondary control. This type of switch mode power supply is particularly
suitable as an AC/DC power supply for DVD, VCD and VCR. The PWM controller ICE2A265 chip
used for this application is a current-controlled pulse width modulator with integrated CoolMOS™
power switch. ICE2A265 is the second generation CoolSET™ which provides several special
enhancements to satisfy the needs for low power standby and protection features. In standby mode
frequency reduction is used to lower the power consumption and support a stable output voltage in this
mode. In case of failure modes like open loop, overvoltage or overload due to short circuit the device
switches in Auto Restart Mode which is controlled by the internal protection unit. By means of the
internal precise peak current limitation the dimension of the transformer and the secondary diode can
be lower which leads to more cost efficiency.
Evaluation board
Technical specifications:
Input voltage
Input frequency
Output voltage and current
Digital +5V
Digital +3.3V
Standby +5V
Analog +5V
Audio +9V
Audio -9V
Motor +9V
VFD display 4.5V
Output power
Efficiency
Switching frequency
Standby load condition
Standby power
85VAC~265VAC
50Hz, 60Hz
5V
3.3V
STB+5V
A+5V
+9V
-9V
M+9V
-25V
Floating 4.5V
23.9W
70% excluding linear regulator
100KHz
STB+5V/0.03A only
<1W
1.5A
0.7A
0.03A
0.3A
0.2A
0.2A
0.6A
0.03A
0.1A
Circuit Description
Line Input
The AC line input side comprises the input fuse FUSE1 as overcurrent protection. The choke L1, X2capacitors C1 and C2 and Y1-capacitor C8 and C9 as radio interference suppressors. After the bridge
rectifier BR1 and the input capacitor C3, a voltage of 80 to 380 VDC depending on input voltage is
available.
PWM Control and Power Stage
The PWM pulse is generated by 8-pin CoolSET™ ICE2A265. ICE2A265 is an integrated power IC
which includes both of the current mode PWM controller and power MOSFET with 650V breakdown
voltage. The control IC and Power MOS are fabricated by the different optimized chip technologies
respectively and no compromise like monolithic approaches is necessary. The control IC is fabricated
by the reliable bipolar technology. Moreover, the power stage is handled by evolutionary CoolMOS™
technology.
Clamping Network
R3, C4 and D1 dissipate the energy of the leakage inductance.
Primary Current Sense
The primary current is sensed by the external shunt resistor R6. The sense voltage is fed into
ICE2A265 and compares to the internal control voltage for PWM control.
Output Stage
On the secondary side the power is coupled out via a group of fast-acting diodes Df1, D11, D21, D31,
D41 and D51. The capacitors Cf1, C11, C21, C31, C41 and C51 provide energy buffering following
with the LC filters to reduce the output voltage ripple considerably. Storage Cf1, C11, C21, C31, C41
and C51 are designed to have an internal resistance as small as possible (ESR). This minimizes the
output voltage ripple caused by the triangular current characteristic. Q21, Q41 and Q51 are used to cut
the current during the standby mode. Two linear regulators are used to provide A+5V and 3.3V with
high accuracy.
Feedback Loop
The output voltage is sensed by the voltage divider of Rc4 and Rc5 and compare to TL431 internal
reference voltage. The output voltage of TL431 is transferred to the primary via optocoupler for
regulation control. The secondary regulation control is adopted with TL431 and optocoupler. The
compensation network Cc1, Cc2, Rc3 constitutes the external circuitry of the error amplifier of TL431.
This circuitry allows the feedback to be precisely matched to dynamically varying load conditions,
thereby providing stable control. The maximum current through the optocoupler diode and the voltage
reference is limited by the resistor Rc2. Optocoupler IC2 is used for floating transmission of the control
signal to the “FB” input of the ICE2A265. The optocoupler meets DIN VDE 884 requirements.
Circuit Operation
Startup
From the DC input voltage, the chip's starting current supply is derived using the resistors R1 and R2.
Because of the low current less than 55uA, high-value resistors can be used. Series connection of the
resistors is necessary for reasons of insufficient dielectric strength of the individual resistors. The IC
remains inactive during the Vcc charge up. When the voltage on Vcc reaches 13.5V (typ.), the IC turn
on threshold voltage, the SMPS is going to start. The Soft-Start function is realized by RC charging
circuit of an internal resistor and the external capacitor C7. The pulse width is gradually increased
during a soft start.
Normal Mode Operation
After startup, the secondary output voltage is built up. If the Stby input signal is high, the SMPS will go
into in normal mode. The switches Q21, Q41 and Q51 are turned on and the IC is working in 100KHz
switching frequency. During normal operation, the power supply is provided via a separate transformer
winding with associated rectifier D2. Resistor R4 is used to limit the IC supply current.
Standby Mode Operation
If the Stby input signal is low, the switches Q21, Q41 and Q51 are off and the output voltages of 5V,
3.3V, A+5V, +9V and –9V are dropped to zero. The DVD microcontroller will switch off most of its
function blocks and VFD display is inactive. There is almost no current from M+9V because DC motor
does not work. During the standby mode, the voltage on the IC FB pin is low due to the negative
feedback regulation. Because of the internal frequency course dependence on FB pin voltage, the
switching frequency is reduced to 21.5KHz. It will help to lower the standby power due to the
switching loss.
Protection Features
Overload & open loop protection in normal operation
The detection of open loop or overload is provided by two comparators. The detection is activated and
IC will go to auto-restart mode when the voltage at pin SST exceeds 5.3V and feedback voltage V FB
to exceed the threshold of 4.8V.
Open loop protection during start-up
The above open loop protection is not active in startup with softstart voltage is lower than 5.3V. The
open loop protection is realized by Vcc overvoltage protection during startup when Soft-Start voltage is
lower than 4.0V and the voltage at pin FB is above 4.8V. If Vcc exceeds 16.5V (typ.), IC will stop and
go to auto-restart mode. This protection will help to prevent the extremely high voltages on secondary
output in case of startup at no load condition with open loop fault.
Current Limiting
There is a cycle by cycle current limiting realized by the Current-Limit Comparator to provide the
overcurrent detection. The source current of the integrated CoolMOSä is sensed via an external sense
resistor Rsense. By means of Rsense the source current is transformed to a sense voltage Vsense. When
the voltage Vsense exceeds the internal threshold voltage Vcsth the Current-Limit-Comparator
immediately turns off the gate drive. To prevent the Current Limiting from distortions caused by
leading edge spikes a Leading Edge Blanking is integrated at the Current Sense.
Current overshoot Minimization by propagation delay compensation
In case of overcurrent detection by current sense the shut down of CoolMOS™ is delayed due to the
propagation delay of the circuit. This delay causes an overshoot of the peak current Ipeak which
depends on the ratio of di/dt of the peak current. A propagation delay compensation is integrated to
reduce the tolerance of the dependence on di/dt of the internal current limiting at ±5%.
Over temperature protection
Thermal Shut Down is latched by the Error-Latch when junction temperature Tj of IC is exceeding an
internal threshold of 140°C. In that case the IC switches in Auto Restart Mode.
Circuit Diagram
PCB layout top layer
PCB layout Bottom:
Component List:
Designators
BR1
C1
C10
C11
C2
C21
C22
C3
C31
C32
C4
C41
C42
C43
C5
C51
C52
C53
C6
C7
C8
C9
Cc1
Cc2
Cf1
Cf2
Connector
Copt1
Copt2
D1
D11
D2
D21
D31
D41
D51
Df1
FUSE Holder
FUSE1
HK1
HK2
HK3
IC1
IC2
IC3
IC4
IC5
JP1
JP2
Type
RS204
0.1uF/275V, X2
Not connected
100uF/50V
0.1uF/275V, X2
220uF/16V
100uF/16v
47uF/400
470uF/16V
220uF/16V
10nF/630V
470uF/16V
220uF/16V
220uF/10V
47uF/25V
2200/10
1000uF
470uF/10V
2.2nF
1uF
2200p/250, Y2
2200p/250, Y2
0.1uF
6.8nF
100uF/25V
47uF/25V
4.7nF/250V, Y2
4.7nF/250V, Y2
UF4006
UF4003
1N4148
UF4002
UF5401
UF5401
MBR760
UF4001
1A
Heat Sink
Heat Sink
Heat Sink
ICE2A265
SFH617A-3
TL431
L7805
LM1117
Jumper
Jumper
Qty
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
9
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
JP3
JP4
L1
L2
L21
L31
L41
L51
Lf1
M3 Nut
M3 Screw
Q21
Q22
Q41
Q42
Q51
R1
R2
R21
R22
R23
R24
R3
R4
R41
R42
R43
R44
R5
R6
Rc1
Rc2
Rc3
Rc4
Rc5
Rf1
RT1
T1
VR1
ZDf1
Jumper
Jumper
Common mode choke, 50mH
Ferrite Bead
20uH
20uH
20uH
20uH
20uH
BC639
BC558
BC640
BC548
IPP15N03L
470k, 1/2W
470k, 1/2W
10k
4.7k
10k
1k
82k, 2W
8.2
6.8k
330
4.7k
4.7k
22
0.51ohm, 1/2W
680
1k
10k
2.4k, 1%
2.4k, 1%
10
S235/5
ER28 Transformer
S07K275
5V1
1
1
1
1
1
1
1
1
1
3
3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Transformer construction:
Layer No.
9
8
7
6
5
4
3
2
1
Start
7
12
14
14
15
16
18
2
5
Stop
9
11
10
13
14
17
17
1
7
No. of Turns
22
3
11
5
5
5
3
8
22
Core Inside
Wire Size
1 x Φ0.28mm
1 x Φ0.28mm
1 x Φ0.28mm
3 x Φ0.28mm
3 x Φ0.28mm
3 x Φ0.28mm
8 x Φ0.28mm
1 x Φ0.28mm
1 x Φ0.28mm
Core: ER28/N67
Primary Inductance, Lp=269µH, measured between pin 5 and pin 9
(Gapped to Inductance)
Primary
Secondary
Primary
265
220
110
85
32.8
17.3
7.8
31.2
16.9
7.6
29.8
16.4
7.9
29.9
16.5
8.2
Pin(w)
Vo1
SMPS
Total
(+5V)
Po(W)
Po(w)
(Excluding (Including
Regulators) Regulators
)
22.87
20.53
4.92
12.46
11.01
4.97
5.77
5.07
5
22.86
20.53
4.92
12.44
11.00
4.97
5.78
5.07
5
22.90
20.55
4.92
12.49
11.03
4.97
5.78
5.07
5.01
22.92
20.57
4.92
12.47
11.02
4.97
5.78
5.07
5.01
3.26
3.27
3.28
3.26
3.27
3.28
3.26
3.27
3.28
3.26
3.27
3.29
Vo2
(+3.3V)
4.92
4.92
4.93
4.92
4.92
4.93
4.92
4.92
4.93
4.92
4.92
4.93
Vo3
(A+5V)
8.85
8.78
8.56
8.83
8.68
8.58
8.86
8.8
8.6
8.88
8.8
8.6
Vo4
(+9V)
9
8.9
9.5
9
8.9
9.5
9
8.9
9.6
9
8.9
9.7
Vo5
(M+9V)
-9.22
-9.16
-8.7
-9.22
-9.16
-8.72
-9.25
-9.2
-8.7
-9.28
-9.17
-8.7
Vo6
(-9V)
-25.51
-23.41
-21.75
-25.58
-23.49
-21.79
-25.97
-23.65
-21.66
-26.08
-23.46
-21.64
4.42
4.16
3.84
4.43
4.16
3.84
4.46
4.20
3.81
4.49
4.18
3.79
4.96
4.99
5
4.96
4.99
5
4.96
4.99
5.01
4.96
4.99
5.01
Vo7
Vo8
Vo9
(-25V) (F4.5V) (STB+5V)
5V/1.3A, 3.3V/0.7A, A+5V/0.3A, +9V/0.2A, M+9V/0.6A, -9V/0.2A, -25V/0.03A, F+4.5V/0.1A, STB+5V/0.03A
5V/0.6A, 3.3V/0.4A, A+5V/0.2A, +9V/0.1A, M+9V/0.3A, -9V/0.1A, -25V/0.03A, F+4.5V/0.1A, STB+5V/0.03A
5V/0.2A, 3.3V/0.2A, A+5V/0.1A, +9V/0.1A, M+9V/0A, -9V/0.1A, -25V/0.03A, F+4.5V/0.1A, STB+5V/0.03A
full load
med load
light load
full load
med load
light load
full load
med load
light load
full load
med load
light load
Load Test
Vin(V)
full load
med load
light load
Test report:
70%
72%
74%
73%
74%
76%
77%
76%
73%
77%
76%
70%
SMPS
Efficiency
(Excluding
Regulators)
63%
64%
65%
66%
65%
67%
69%
67%
64%
69%
67%
62%
Total
Efficiency
(Including
Regulators)
265
220
110
85
stby
load
stby
load
stby
load
stby
load
0.9
0.8
0.5
0.5
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0.16
0
0
0
0
0
0
0
0
0
0
0
0
Standby Test:
stby load: STB+5V/0.03A only
Vo2
Vo3
Vin(V)
Pin(w) SMPS Po(W) Total Po(w) Vo1
(Including (+5V) (+3.3V) (A+5V)
(Excluding
Regulators) Regulators)
0
0
0
0
Vo4
(+9V)
9.3
9.3
9.1
9.1
Vo5
(M+9V)
0
0
0
0
Vo6
(-9V)
-24.42
-24.64
-23.71
-23.87
6.54
6.68
6.30
6.40
5.11
5.11
5.05
5.04
Vo7
Vo8
Vo9
(-25V) (F4.5V) (STB+5V)
18%
20%
32%
SMPS
Efficiency
(Excluding
Regulators)
32%
18%
20%
32%
Total
Efficiency
(Including
Regulators)
32%
Conducted EMI spectrum at 240VAC input
References:
[1]
Harald Zöllinger and Rainer Kling, ICE2AXXX for OFF-Line Switch Mode Power Supplies
(SMPS), Application Note, Infineon Technologies.
[2]
CoolSETä-II Off-line SMPS Current Mode Controller with High Voltage 650V/800V
CoolMOSä on Board Datasheet, Infineon Technologies.
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