Application Note: STR-A6000 Series PWM Off-Line Switching Regulators

Application Information
STR-A6000 Series PWM Off-Line Switching Regulator ICs
General Description
The STR-A6000 series are power ICs for switching power
supplies, incorporating a power MOSFET and a current
mode PWM controller IC in one package. To achieve low
power consumption, the product includes a startup circuit
and a standby function in the controller.
Not to scale
The switching modes are automatically changed according to load conditions so that the PWM mode is in normal
operation and the burst mode is in light load condition. The
rich set of protection features helps to realize low component counts, and high performance-to-cost power supply.
Features and Benefits
▪ Current mode PWM control
▪ Brown-In and Brown-Out function: auto-restart, prevents
excess input current and heat rise at low input voltage
▪ Auto Standby function: improves efficiency by burst mode
operation in light load
▫ Normal load operation: PWM mode
▫ Light load operation: Burst mode
▪ No load power consumption < 25 mW
▪ Random Switching function: reduces EMI noise, and
simplifies EMI filters
▪ Slope Compensation function: avoids subharmonic
oscillation
▪ Leading Edge Blanking function
▪ Audible Noise Suppression function during Standby mode
DIP8 package
▪ Protection features
▫ Overcurrent Protection function (OCP): pulse-by-pulse,
with input compensation function
▫ Overvoltage Protection function (OVP): latched shutdown
▫ Overload Protection function (OLP): auto-restart, with timer
▫ Thermal shutdown protection (TSD): latched shutdown
Applications
Switching power supplies for electronic devices such as:
• Battery charger for mobile phone, digital camera, camcorder, electric shaver, emergency/guide light, and so forth
• Standby power supply for LCD/PDP television, desktop
PC, multi-function printer, audio equipment, and so forth
• Small switch-mode power supply (SMPS) for printer,
BD/DVD player, CD player, set-top-box, and so forth
• Auxiliary power supply for air conditioner, refrigerator,
washer, dishwasher, and so forth
The product lineup for the STR-A6000 series provides the following options
Power MOSFET
Output Power1, POUT (W)
Open Frame
Adaptor
Part Number
Features
VDSS(min)
RDS(ON)(max)
85 to
85 to
(V)
(Ω)
230 VAC
230 VAC
265 VAC
265 VAC
STR-A6051M
STR-A6052M
STR-A6053M
STR-A6079M
STR-A6059H
STR-A6061H
STR-A6062H
STR-A6069H
STR-A6061HD
STR-A6062HD
STR-A6063HD
STR-A6069HD
fOSC = 67 kHz
650
800
650
fOSC = 100 kHz
fOSC = 100 kHz,
two types of OCP2
700
700
3.95
2.8
1.9
19.2
6
3.95
2.8
6
3.95
2.8
2.3
6
30
35
41
13
30
35
38
30
35
38
40
30
1The
21
25
29
9
19
24
26
19
24
26
27
19
20
23
26
8
17
21
23
17
21
23
25
17
16
19
22
6
11
15
18
11
15
18
20
11
listed output power is based on the thermal ratings, and the peak output power can be 120% to 140% of the value stated here. At low output voltage and short duty cycle, the output power may be less than the value stated here.
2The products suffixed D have an additional OCP function which operates during leading edge blanking period, to operate as protection at the condition such as output windings shorted or unusual withstand voltage of secondary-side diodes.
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
http://www.sanken-ele.co.jp/en/
Table of Contents
General Description
1
Absolute Maximum Ratings
2
Electrical Characteristics
3
Functional Block Diagram
5
Pin List Table
5
Typical Application Circuit
6
Package Diagram
7
Marking Diagram
7
Functional Description
8
Startup Operation
Undervoltage Lockout (UVLO) Circuit
Bias Assist Function
Constant Voltage Control Operation
Auto Standby Mode Function
Random Switching Function
Brown-In and Brown-Out Function
Overcurrent Protection Function (OCP)
Overvoltage Protection Function (OVP)
Overload Protection Function (OLP)
Thermal Shutdown Function (TSD)
Design Notes
9
10
11
11
13
13
14
15
15
Peripheral Components
15
PCB Trace Layout and Component Placement 17
8
8
9
Pattern Layout Example
18
Reference Design of Power Supply
19
Important Notes
21
Absolute Maximum Ratings
• The STR-A6059H is used as an example for the STR-A6000 series.
• Refer to the datasheet of each product for these details.
• The polarity value for current specifies a sink as "+," and a source as
"−," referencing the IC.
Absolute Maximum Ratings Unless otherwise specified, TA = 25°C
Characteristic
Drain Peak Current1
Avalanche Energy1
Symbol
IDPEAK
EAS
Conditions
Single pulse
Single pulse, VDD = 99 V, L = 20 mH
Pins
Rating
Unit
8−1
1.8
A
8−1
24
mJ
ILPEAK
8−1
1.8
A
S/OCP Pin Voltage
VOCP
1−3
−2 to 6
V
Control Part Input Voltage
VCC
5−3
32
V
FB/OLP Pin Voltage
VFB
4−3
−0.3 to 14
V
FB/OLP Pin Sink Current
IFB
4−3
1.0
mA
BR Pin Voltage
VBR
2−3
−0.3 to 7
V
BR Pin Sink Current
IBR
2−3
1.0
mA
Power Dissipation of MOSFET
PD1
8−1
1.35
W
Mounted on 15 mm × 15 mm printed circuit board
Power Dissipation of Control Part
PD2
5−3
1.2
W
Operating Ambient Temperature2
TOP
–
−20 to 125
°C
Storage Temperature
Tstg
–
−40 to 125
°C
Channel Temperature
Tch
–
150
°C
1Refer
2The
to individual product datasheet for details; value differs among products.
recommended internal frame temperature, TF , is 115°C (max).
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
2
Electrical Characteristics
• The STR-A6059H is used as an example for the STR-A6000 series.
• Refer to the datasheet of each product for these details.
• The polarity value for current specifies a sink as "+," and a source as
"−," referencing the IC.
Electrical Characteristics of Control Part Unless otherwise specified, TA = 25°C, VCC = 18 V
Characteristic
Symbol
Conditions
Pins
Min.
Typ.
Max.
Unit
V
Operation Start Voltage
VCC(ON)
5−3
13.8
15.3
16.8
Operation Stop Voltage1
VCC(OFF)
5−3
7.3
8.1
8.9
V
5−3
–
–
2.5
mA
Circuit Current in Operation
ICC(ON)
VCC = 12 V
Minimum Start Voltage
VST(ON)
5−3
–
38
–
V
Startup Current
ISTARTUP
VCC = 13.5 V
5−3
−3.7
−2.5
−1.5
mA
Startup Current Threshold Biasing Voltage1
VCC(BIAS)
ICC = −100 μA
5−3
8.5
9.5
10.5
V
Average Operation Frequency2
fOSC(AVG)
8−3
90
100
110
kHz
Frequency Modulation Deviation2
Δf
8−3
–
8
–
kHz
DMAX
8−3
77
83
89
%
On-Time2
tON(MIN)
–
–
470
–
ns
Leading Edge Blanking Time2
tBW
–
–
280
–
ns
DPC
–
–
33
–
mV/μs
DDPC
–
–
36
–
%
V
Maximum Duty Cycle
Minimum
OCP Compensation
Coefficient2
OCP Compensation Duty Cycle Limit
OCP Threshold Voltage at Zero Duty Cycle
VOCP(L)
1−3
0.70
0.78
0.86
OCP Threshold Voltage at 36% Duty Cycle
VOCP(H)
VCC = 32 V
1−3
0.81
0.9
0.99
V
Maximum Feedback Current
IFB(MAX)
VCC = 12 V
4−3
−340
−230
−150
μA
Minimum Feedback Current
IFB(MIN)
4−3
−30
−15
−7
μA
FB/OLP Pin Oscillation Stop Threshold
Voltage
VFB(STB)
4−3
0.85
0.95
1.05
V
OLP Threshold Voltage
VFB(OLP)
4−3
7.3
8.1
8.9
V
4−3
54
68
82
ms
5−3
–
300
600
μA
V
OLP Delay Time
OLP Operation Current
tOLP
ICC(OLP)
VCC = 12 V
FB/OLP Pin Clamp Voltage
VFB(CLAMP)
4−3
11
12.8
14
Brown-In Threshold Voltage
VBR(IN)
VCC = 32 V
2−3
5.2
5.6
6
V
VBR(OUT)
VCC = 32 V
2−3
4.45
4.8
5.15
V
VBR(CLAMP) VCC = 32 V
2−3
6
6.4
7
V
2−3
0.3
0.48
0.7
V
5−3
26
29
32
V
5−3
–
700
–
μA
–
135
–
–
°C
Brown-Out Threshold Voltage
BR Pin Clamp Voltage
BR Function Disabling Threshold Voltage
VBR(DIS)
VCC Pin OVP Threshold Voltage
VCC(OVP)
Latch Circuits Holding Current3
ICC(LATCH)
Thermal Shutdown Temperature
Tj(TSD)
VCC = 32 V
VCC = 9.5 V
1V
CC(BIAS) > VCC(OFF) always.
2Refer to individual product datasheet
3A
for details; value differs among products.
latch circuit is a circuit operated with Overvoltage Protection function (OVP) and/or Thermal Shutdown Protection function (TSD) in operation.
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
3
Reference Parameter Comparison Between STR-A6000M Type and STR-A6000H/HD Types
Different ratings
Characteristic
Average Operation Frequency
Frequency Modulation Deviation
Minimum Duty Cycle
Leading Edge Blanking Time
OCP Compensation Coefficient
Symbol
STR-A6000M Type
STR-A6000H / HD Types
Unit
Min.
Typ.
Max.
Min.
Typ.
Max.
fOSC(AVG)
60
67
74
90
100
110
kHz
Δf
―
5
―
―
8
―
kHz
tON(MIN)
―
540
―
―
470
―
ns
tBW
―
340
―
―
280
―
ns
DPC
―
22
―
―
33
―
mV/μs
Electrical Characteristics of MOSFET Unless otherwise specified, TA is 25°C
Pins
Min.
Typ.
Max.
Unit
Drain-to-Source Breakdown Voltage*
Characteristic
VDSS
8–1
650
–
–
V
Drain Leakage Current
IDSS
8–1
–
–
300
μA
On-Resistance*
RDS(ON)
8–1
–
–
6
Ω
Switching Time*
tf
8–1
–
–
250
ns
–
–
–
22
°C/W
Thermal Resistance*
Symbol
Rθch-C
Conditions
The thermal resistance between
the channels of the MOSFET and
the case. Case temperature, TC, is
measured at the center of the case
top surface.
*Refer to individual product datasheet for details; value differs among products.
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
4
Functional Block Diagram
5
VCC
Startup
UVLO
2
BR
REG
VREG
OVP
D/ST
7,8
TSD
Brown-In/
Brown-Out
6.4 V
PWM OSC
DRV
SQ
R
OCP
7V
VCC
Drain Peak Current
Compe nsa tion
OLP
Fe edback
Control
FB/OLP
4
S/OCP
GND
Slope
Compensation
12.8 V
1
LEB
3
Pin List Table
S/OCP 1
8 D/ST
BR 2
7 D/ST
GND 3
5 VCC
FB/OLP 4
Number
Name
1
S/OCP
STR-A6000-AN, Rev. 4.1
Function
MOSFET source, and input for Overcurrent Protection (OCP) signal
2
BR
3
GND
Input for Brown-In and Brown-Out detection voltage
4
FB/OLP
Feedback signal input for constant voltage control signal, and input of Overload
Protection (OLP) signal
5
VCC
Power supply voltage input for Control Part and input of Overvoltage Protection
(OVP) signal
6
–
7, 8
D/ST
Ground
(Pin removed)
MOSFET drain, and input of the startup current
SANKEN ELECTRIC CO., LTD.
5
Typical Application Circuit
The following drawings show circuits enabled and disabled the
Brown-In/Brown-Out function.
• In applications having a power supply specified such that VDS
has large transient surge voltages, a clamp snubber circuit of a
capacitor-resistor-diode (CRD) combination should be added
on the primary-side winding P, or a damper snubber circuit of
a capacitor (C) or a resistor-capacitor (RC) combination should
be added between the D/ST pin and the S/OCP pin.
The following design features should be observed:
• The PCB traces from the D/ST pins should be as wide as possible, in order to enhance thermal dissipation.
CRD clamp snubber
BR1
C1
PC1
P
C51
D1
RB
S
D2
8
D/ST D/ST
C4
NC
R51
R55
R52
C53
C52 R53
R2
U51
5
7
VCC
VOUT
R54
R1
C5
RA
L51
D51
T1
VAC
R56
D
C2
U1
GND
STR-A6000
S/OCP BR GND FB/OLP
C(CR)
Dumper snubber
1
RC
2
3
4
C10
C3
PC 1
ROCP
C9
Typical application circuit example, enabled Brown-In/Brown-Out function (DC line detection)
CRD clamp snubber
BR1
PC1
P
C51
D1
S
D2
8
C4
NC
R55
R52
U51
VCC
C2
R51
C53
C52 R53
R2
5
7
VOUT
R54
R1
C5
C1
D/ST D/ST
L51
D51
T1
VAC
R56
D
U1
GND
STR-A6000
S/OCP BR GND FB/OLP
C(CR)
Dumper snubber
1
2
ROCP
3
4
C3
PC 1
C9
Typical application circuit example, disabled Brown-In/Brown-Out function
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
6
Package Diagram
• DIP8 package
• The following show a representative type of DIP8.
• The pin 6 is removed to provide greater creepage and clearance isolation between
the high voltage pins (pins 7 and 8: D/ST) and the low voltage pin (pin 5: VCC).
9.4 ±0.3
5
1
4
6.5 ±0.2
8
1.0 +0.3
-0.05
+0.3
1.52
-0.05
3.3 ±0.2
7.5 ±0.5
4.2 ±0.3
3.4 ±0.1
(7.6 TYP)
0.2 5 + 0.
- 0.01
5
2.54 TYP
0.89 TYP
Marking Diagram
0~15°
0~15°
0.5 ±0.1
Unit: mm
STR-A6xxH or STR-A6xxM
8
STR-A6xxHD
8
A60xxx
SK YMD
Lot Number
Y is the last digit of the year (0 to 9)
M is the month (1 to 9, O, N, or D)
D is a period of days (1 to 3):
1 – 1st to 10th
2 – 11th to 20th
3 – 21st to 31st
Sanken Control Number
1
A60xxH
SK YMD D
Part Number
1
Part Number
Lot Number
Y is the last digit of the year (0 to 9)
M is the month (1 to 9, O, N, or D)
D is a period of days (1 to 3):
1 – 1st to 10th
2 – 11th to 20th
3 – 21st to 31st
Sanken Control Number
Pb-free.Device composition compliant with the RoHS directive.
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
7
Functional Description
• All of the parameter values used in these descriptions are typical
values, according to the STR-A6059H specification, unless they
are specified as minimum or maximum.
• With regard to current direction, "+" indicates sink current (toward the IC) and "–" indicates source current (from the IC).
BR1
T1
VAC
Startup Operation
C1
Figure 1 shows the VCC pin peripheral circuit, disabled the
Brown-In/Brown-Out function by connecting the BR pin trace to
the GND pin trace.
The built-in startup circuit is connected to the D/ST pin. When the
D/ST pin voltage increases to VST(ON) = 38 V, the startup circuit
starts operation.
In figure 1, the Startup Current, ISTARTUP , which is a constant
current of –2.5 mA, is provided from the IC to capacitor C2 connected to the VCC pin, and it charges C2. When the VCC pin
voltage increases to VCC(ON) = 15.3 V, the IC starts operation. After
that, the startup circuit stops automatically, in order to eliminate its
own power consumption.
7,8
D/ST
VCC
5
UI
BR
2
D2
C2
GND
P
R2
VD
D
3
Figure 1. VCC pin peripheral circuit
During the IC operation, the rectified voltage from the auxiliary
winding voltage, VD , of figure 1 becomes a power source to the
VCC pin.
The winding turns of winding D should be adjusted so that the
VCC pin voltage is applied to equation (1) within the specifications of the input voltage range and output load range of the power
supply. The target voltage of the winding D is about 15 to 20 V.
VCC(BIAS)(max) < VCC < VCC(OVP)(min)
(1)
ICC
ICC(ON)
= 2.5 mA (max)
tSTART
z
C2 ×
VCC(ON) – VCC(INT)
where:
|ISTARTUP|
Stop
The startup time, tSTART , is determined by the value of C2, and it is
approximately given as below:
Start
⇒ 10.5 (V) < VCC < 26.0 (V)
8.5 V
VCC(OFF)
VCC pin voltage
15 V
VCC(ON)
(2)
tSTART is the startup time in s, and
VCC(INT) is the initial voltage of the VCC pin in V.
Figure 2. VCC versus ICC
Undervoltage Lockout (UVLO) Circuit
Figure 2 shows the relationship of VCC and ICC . After the IC starts
operation, when the VCC pin voltage decreases to VCC(OFF) =
8.1 V, the IC stops switching operation by the UVLO (Undervoltage Lockout) circuit and reverts to the state before startup.
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
8
Bias Assist Function
Figure 3 shows the VCC pin voltage behavior during the startup
period. When the VCC pin voltage increases to VCC(ON) = 15.3 V,
the IC starts operation. Thus, the circuit current, ICC , increases,
and the VCC pin voltage begins dropping. At the same time, the
auxiliary winding voltage, VD , increases in proportion to the
output voltage rise.
Thus, the VCC pin voltage is set by the balance between dropping
due to the increase of ICC and rising due to the increase of the
auxiliary winding voltage, VD .
Just at the turning-off of the power MOSFET, a surge voltage
occurs at the output winding. If the feedback control is activated
by the surge voltage on light load condition at startup, the output
power is restricted and the output voltage decreases.
VCC
pin voltage
Startup success
IC startup
Target
Operating
Voltage
Increasing by
output voltage rising
Bias Assist period
VCC(ON)
VCC(BIAS)
VCC(OFF)
Startup failure
Time
Figure 3. VCC pin voltage during startup period
When the VCC pin voltage decreases to VCC(OFF) = 8.1 V, the IC
stops switching operation and a startup failure occurs.
In order to prevent this, the Bias Assist function is activated when
the VCC pin voltage decreases to the Startup Current Threshold
Biasing Voltage, VCC(BIAS) = 9.5 V, during a state of operating
feedback control. While the Bias Assist function is activated, any
decrease of the VCC pin voltage is counteracted by providing the
Startup Current, ISTARTUP , from the startup circuit. Thus, the VCC
pin voltage is kept almost constant.
By the Bias Assist function, the value of C2 is allowed to be small
and the startup time becomes shorter. Furthermore, because the
increase of VCC pin voltage becomes faster when the output
runs with excess voltage, the response time of the OVP function
becomes shorter.
UI
S/OCP
1
GND
3
VROCP
STR-A6000-AN, Rev. 4.1
IFB
Target voltage including
Slope Compensation
VSC
–
The FB/OLP pin voltage is internally added the slope compensation at the feedback control (refer to Function Block Diagram
section), and the target voltage, VSC , is generated. The IC compares the voltage, VROCP , of a current detection resistor with the
target voltage, VSC , by the internal FB comparator, and controls
the peak value of VROCP so that it gets close to VSC , as shown in
figures 4 and 5.
C3
Figure 4. FB/OLP pin peripheral circuit
+
The constant output voltage control function uses current mode
control (peak current mode), which enhances response speed and
provides stable operation.
4
PC1
ROCP
It is necessary to check and adjust the startup process based on
actual operation in the application, so that the startup failure does
not occur.
Constant Voltage Control Operation
FB/OLP
VROCP
FB Comparator
OCP pin voltage
Drain current ID
Figure 5. Drain current, ID , and FB comparator in steady operation
SANKEN ELECTRIC CO., LTD.
9
• Light load conditions
When load conditions become lighter, the output voltage, VOUT ,
increases. Thus, the feedback current from the error amplifier
on the secondary-side also increases. The feedback current is
sunk at the FB/OLP pin, transferred through a photocoupler,
PC1, and the FB/OLP pin voltage decreases. Thus, VSC
decreases, and the peak value of VROCP is controlled to be low,
and the peak drain current of ID decreases. This control prevents
the output voltage from increasing.
• Heavy load conditions
When load conditions become greater, the IC performs the
inverse operation to that described above. Thus, VSC increases
and the peak drain current of ID increases. This control prevents
the output voltage from decreasing.
In the current mode control method, when the drain current waveform becomes trapezoidal in continuous operating mode, even
if the peak current level set by the target voltage is constant, the
on-time fluctuates based on the initial value of the drain current.
This results in the on-time fluctuating in multiples of the fundamental operating frequency as shown in figure 6. This is called
the subharmonics phenomenon.
Target voltage
without Slope Compensation
tON1
t
Even if subharmonic oscillations occur when the IC has some
excess supply being out of feedback control, such as during
startup and load shorted, this does not affect performance of
normal operation.
In the current mode control method, the FB comparator and/or
the OCP comparator may respond to the surge voltage resulting
from the drain surge current in turning-on the power MOSFET.
As a result, the power MOSFET may turn off irregularly. In order
to prevent this response to the surge voltage in turning-on the
power MOSFET, Leading Edge Blanking, tBW = 280 ns (340 ns
for STR-A6000M type), is built-in.
Auto Standby Mode Function
Auto Standby mode is activated automatically when the drain
current, ID , reduces under light load conditions, at which ID is
less than 15% to 20% of the maximum drain current (it is in the
Overcurrent Protection state).
The operation mode becomes burst oscillation, as shown in figure 7. Burst mode reduces switching losses and improves power
supply efficiency because of periodic non-switching intervals.
Generally, to improve efficiency under light load conditions,
the frequency of the burst mode becomes just a few kilohertz.
Because the IC suppresses the peak drain current well during
burst mode, audible noises can be reduced.
tON2
t
In order to avoid this, the IC incorporates the Slope Compensation function. Because the target voltage is added a down-slope
compensation signal, which reduces the peak drain current as the
on-duty gets wider relative to the FB/OLP pin signal to compensate VSC, the subharmonics phenomenon is suppressed.
t
Figure 6. Drain current, ID , waveform in subharmonic oscillation
If the VCC pin voltage decreases to VCC(BIAS) = 9.5 V during the
transition to the burst mode, the Bias Assist function is activated
and stabilizes the standby mode operation, because ISTARTUP is
Burst oscillation
Output
current, IOUT
Drain
current, ID
Below several kHz
Normal operation
Standby operation
Normal operation
Figure 7. Auto Standby mode timing
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
10
provided to the VCC pin so that the VCC pin voltage does not
decrease to VCC(OFF).
However, if the Bias Assist function is always activated during
steady-state operation including standby mode, the power loss
increases. Therefore, the VCC pin voltage should be more than
VCC(BIAS), for example, by adjusting the turns ratio of the auxiliary winding and secondary-side winding and/or reducing the
value of R2 in figure 16 (refer to Peripheral Components section
for a detail of R2).
Random Switching Function
The IC modulates its switching frequency randomly within Δf =
± 4% superposed on the average operation frequency, fOSC(AVG) .
The conduction noise with this function is smaller than that without this function, and this function can simplify noise filtering of
the input lines of power supply.
Brown-In and Brown-Out Function by DC Line
Detection
The BR pin detects a voltage proportional to the DC input voltage
(C1 voltage), with the resistive voltage divider RA, RB, and RC
connected between the DC input and GND, plus C10 connected
to the BR pin, as shown in figure 8-9.
This method detects peaks of the ripple voltage of the rectified
AC input voltage, and thus it minimizes the influence of load
conditions on the detecting voltage.
During the input voltage rising from the stopped state of power
supply, when the BR pin voltage increases to VBR(DIS) = 0.48 V or
more, this function is enabled. After that, when the BR pin voltage increases to VBR(IN) = 5.6 V or more and the VCC pin voltage
C1
Brown-In and Brown-Out Function
8
7
5
D/ST D/ST
VCC
UI
This function stops switching operation when it detects low input
line voltage, and thus prevents excessive input current and overheating. During Auto Standby mode, this function is disabled.
S/OCP BR
1
Disabled Brown-In and Brown-Out Function
When the Brown-In and Brown-Out function is unnecessary,
connect the BR pin trace to the GND pin trace so that the BR pin
voltage is VBR(DIS) = 0.48 V or less, as shown in figure 8.
2
GND FB/OLP
3
4
C3
R OCP
PC1
BR pin is connected to GND
Figure 8. The circuit used to disable the Brown-In and Brown-Out function
EIN
ID
C1
RA
EIN
VCC pin voltage
8
RB
VCC(ON)
VCC(OFF)
5
7
D/ST D/ST
NC
VCC
UI
BR pin voltage
VBR(IN)= 5.6 V
S/OCP BR GND FB/OLP
1
RC
2
3
4
C10
C3
VBR(DIS)= 0.48 V
PC1
Drain current, ID
ROCP
Figure 9. Brown-In and Brown-Out function controlled by DC line detection
STR-A6000-AN, Rev. 4.1
VBR(OUT)= 4.8 V
SANKEN ELECTRIC CO., LTD.
68 ms
11
increases to VCC(ON) or more, the IC starts switching operation.
During the input voltage falling from the operated state of power
supply, when the BR pin voltage decreases to VBR(OUT) = 4.8 V or
less for about 68 ms, the IC stops switching operation.
• Component values of the BR pin peripheral circuit:
▫ RA, RB: A few megohms. Because of high DC voltage applied
and high resistance, it is recommended to select a resistor
designed against electromigration or use a combination of
resistors in series for that to reduce each applied voltage,
according to the requirement of the application.
▫ RC: A few hundred kilohms
▫ C10: 100 to 1000 pF for high frequency noise rejection
Brown-In and Brown-Out Function by AC Line
Detection
The BR pin detects a voltage proportional to the AC input voltage, with the resistive voltage divider RA, RB, and RC connected
between one side of the AC line and GND, plus C10 connected to
the BR pin and R9 connected between the BR pin and the VCC
pin, as shown in figure 10.This method detects the AC input voltage, and thus it minimizes the influence from C1 charging and
discharging time, or load conditions, on the detecting voltage.
more, this function is enabled. After that, when the BR pin voltage increases to VBR(IN) = 5.6 V or more and the VCC pin voltage
increases to VCC(ON) or more, the IC starts switching operation.
During the input voltage falling from the operated state of power
supply, when the BR pin voltage decreases to VBR(OUT) = 4.8 V or
less for about 68 ms, the IC stops switching operation.
• Component values of the BR pin peripheral circuit:
▫ RA, RB: A few megohms. Because of high DC voltage applied
and high resistance, it is recommended to select a resistor
designed against electromigration or use a combination of
resistors in series for that to reduce each applied voltage,
according to the requirement of the application.
▫ RC: A few hundred kilohms
▫ C10: 0.047 to 0.47 μF for AC ripple rejection. This should be
adjusted according to values of RA, RB, and RC.
▫ R9: To enable the Brown-In and Brown-Out function, this
value must be adjusted so that the BR pin voltage is more
than VBR(DIS) = 0.48 V when the VCC pin voltage decreases to
VCC(OFF) = 8.1 V.
• High-Speed Latch Release
This method is set together with the High-Speed Latch Release
function.
The Brown-In and Brown-Out function by AC line detection
shown in figure 10 can quickly release the latch mode when the
AC input, VAC, is turned off.
During the input voltage rising from the stopped state of power
supply, when the BR pin voltage increases to VBR(DIS) = 0.48 V or
When the Overvoltage Protection function (OVP) or Thermal
Shutdown function (TSD) are activated, the IC stops switching
BR1
VAC
VAC
ID
C1
R9
RA
8
VCC pin voltage
VCC(ON)
V CC(OFF)
5
7
D/ST D/ST
NC
VCC
UI
RB
BR pin voltage
VBR(IN)= 5.6 V
S/OCP BR GND FB/OLP
1
RC
2
3
4
C10
C3
V BR(OUT)= 4.8 V
V BR(DIS)= 0.48 V
PC1
Drain current, I D
ROCP
68 ms
Figure 10. Brown-In and Brown-Out function controlled by AC line detection
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
12
operation in latch mode. Releasing the latch mode is done by
decreasing the VCC pin voltage below VCC(OFF) = 8.1 V after
unplugging the AC input, or by decreasing the BR pin voltage
below VBR(OUT) = 4.8 V.
This method of unplugging the AC input will spend much time
until the VCC pin voltage decreases below VCC(OFF) = 8.1 V,
because the release time is determined by discharge time of C1.
In contrast, the configuration of the BR pin peripheral circuit
shown in figure 10 makes the releasing process faster. Because
the BR pin voltage immediately decreases to VBR(OUT) = 4.8 V
or less when the AC input, VAC, is turned off, and thus the latch
mode is quickly released.
Overcurrent Protection Function (OCP)
The OCP function detects each peak drain current level of the
power MOSFET by the current detection resistor, ROCP . When
the OCP pin voltage increases to the internal OCP threshold voltage, the IC turns off the power MOSFET on pulse-by-pulse basis,
and limits the output power.
ICs with PWM control usually have some detection delay time on
OCP detection. The steeper the slope of the actual drain current at
a high AC input voltage is, the later the actual detection point is,
compared to the internal OCP threshold voltage. Thus, the actual
OCP point limiting the output current usually has some variation
depending on the AC input voltage, as shown in figure 11.
Because the compensation signal level is designed to depend
upon the on-time of the duty cycle, the OCP threshold voltage
after compensation, VOCP(ONTime), is given as below. However,
when the duty cycle becomes 36% or more, the OCP threshold
voltage after compensation remains at VOCP(H) = 0.9 V, constantly
VOCP(ONTime) (V) = VOCP(L)(V) + DPC (mV/μs)
× On Time (μs).
VOCP(L) is the OCP threshold voltage at zero duty cycle (V),
0.78 V
DPC is the OCP compensation coefficient (mV/μs), 33 mV/μs,
and
On Time is the the on-time of the duty cycle (μs):
On Time = On Duty / fOSC(AVG)
In addition, the products suffixed D have an additional OCP function which operates during leading edge blanking period, tBW.
During tBW from the moment when the power MOSFET is turning on, the OCP threshold voltage becomes VOCP(LEB) = 1.55 V.
This function operates as protection at the condition such as output windings shorted or unusual withstand voltage of secondaryside diodes. After tBW , the OCP threshold voltage is changed to
the value given by the above equation (3).
Overvoltage Protection Function (OVP)
When the voltage between the VCC pin and the GND pin is
applied to the OVP threshold voltage, VCC(OVP) = 29 V or more,
the Overvoltage Protection function (OVP) is activated and the
IC stops switching operation.
Variance resulting
from propagation delay
265 VAC (as an example)
1.0
85VAC (as an example)
VOCP(H)
About 0.83
VOCP(L)
L
ow
AC
in p
ut
gh
Hi
inp
AC
ut
Output Current , IOUT(A)
Figure 11. Output current at OCP without input compensation
STR-A6000-AN, Rev. 4.1
(3)
where:
OCP Threshold Voltage after
Compensated, VOCP(ONTime) (V)
Output Voltage, VOUT (V)
The IC incorporates a built-in Input Compensation function that
superposes a signal with a defined slope into the detection signal
on the OCP pin as shown in figure 12. When AC input voltage is
lower and the duty cycle is longer, the OCP compensation level
increases more than that in high AC input voltage. Thus, the OCP
point in low AC input voltage increases to minimize the difference of OCP points between low AC input voltage and high AC
input voltage, without any additional components.
0.5
0
0
15
36
50
Duty Cycle, D (%)
80
Figure 12. Relationship of duty cycle and OCP threshold voltage after
compensation
SANKEN ELECTRIC CO., LTD.
13
When the VCC pin voltage decreases to VCC(BIAS) = 9.5 V, the
startup circuit provides the Startup Current, ISTARTUP, to the VCC
pin in order to prevent the VCC pin voltage from decreasing
to VCC(OFF) = 8.1 V or less. Thus, the IC maintains latch mode.
Releasing latch mode is done by decreasing the VCC pin voltage below VCC(OFF) = 8.1 V after unplugging the AC input. In
the Brown-In and Brown-Out function by AC line detection,
described above, releasing latch mode is done by the High-Speed
Latch Release decreasing the BR pin voltage below VBR(OUT)
= 4.8 V.
When the auxiliary winding supplies the VCC pin voltage, the
OVP function is able to detect an excessive output voltage, such
as when the detection circuit for output control is open on the
secondary-side, because the VCC pin voltage is proportional to
the output voltage.
UI
GND
VCC
FB /OLP
3 IFB
4
5
D2
PC1
C3
R2
C2
D
Figure 13. FB/OLP pin peripheral circuit
The output voltage of the secondary-side at OVP operation,
VOUT(OVP), is approximately given as below:
VOUT(OVP) =
VOUT(normal operation)
× 29 (V)
VCC(normal operation)
(4)
Overload Protection Function (OLP)
Figure 13 shows the FB/OLP pin peripheral circuit, and figure 14
shows each waveform for OLP operation.
When the peak drain current of ID is limited by OCP operation,
the output voltage, VOUT , decreases and the feedback current
from the secondary-side photocoupler becomes zero. Thus, the
feedback current, IFB , charges C3 connected to the FB/OLP pin
and the FB/OLP pin voltage increases.
When the FB/OLP pin voltage increases to VFB(OLP) = 8.1 V or
more for the OLP Delay Time, tOLP = 68 ms or more, the OLP
function is activated and the IC stops switching operation. When
the OLP function is activated, the Bias Assist function is disabled
and the VCC pin voltage decreases to VCC(OFF) = 8.1 V. Thus,
the IC stops switching operation by the UVLO (Undervoltage
Lockout) circuit and reverts to the state before startup. After that,
the startup circuit is activated, the VCC pin voltage increases to
VCC(ON) = 15.3 V, and the IC starts switching operation again. In
this way, the intermittent operation by UVLO is repeated during
OLP state.
VCC pin
voltage
VCC(ON)
Non-switching interval
V CC(OFF)
FB/OLP pin
voltage
VFB(OLP)
t OLP
t OLP
Drain
current,
ID
Figure 14. OLP operation waveforms
This operation reduces power stress on the power MOSFET and
secondary-side rectifier. Furthermore, this reduces power consumption, because the switching period in this intermittent operation is shorter than non-switching interval. When the fault condition is removed, the IC returns to normal operation automatically.
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
14
Thermal Shutdown Function (TSD)
If the temperature of the control part in the IC increases to more
than Tj(TSD) = 135°C (min), the Thermal Shutdown function
(TSD) is activated and the IC stops switching operation in latch
mode, in the same way as the Overvoltage Protection function
(OVP), described above.
Releasing the latch mode is done by decreasing the VCC pin voltage below VCC(OFF) = 8.1 V after unplugging the AC input. In the
Brown-In and Brown-Out function by AC line detection, releasing the latch mode is done by High-Speed Latch Release decreasing the BR pin voltage below VBR(OUT) = 4.8 V.
T1
VAC
D1
P
C1
D2 R2
RA
8
5
7
D/ST D/ST NC VCC
RB
C2
D
UI
FB/
S/
OCP BR GND OLP
Design Notes
1
Peripheral Components
Take care to use the proper rating and proper type of components.
RC
2
ROCP
3
C10
4
PC1
C3
• Input and output electrolytic capacitors
Apply proper design margin to accommodate ripple current,
voltage, and temperature rise.
Figure 15. IC peripheral circuit
A low ESR type for output smoothing capacitor, designed for
switch-mode power supplies, is recommended to reduce output
ripple voltage.
• Current detection resistor, ROCP
D2
Choose a low inductance and high surge-tolerant type. Because
a high frequency switching current flows to ROCP , a high inductance resistor may cause poor operation.
5
VCC
UI
• BR pin peripheral circuit
Added
D
C2
GND
3
The Brown-In and Brown-Out function has two types of detection method: AC line or DC line. Refer to Brown-In and BrownOut Function section for more details.
• FB/OLP pin peripheral circuit
R2
Figure 16. VCC pin peripheral circuit
C3, located between the FB/OLP pin and the GND pin in
figure 15, performs high frequency noise rejection and phase
compensation, and should be connected close to these pins.
The reference value of C3 is about 2200 pF to 0.01 μF, and
should be selected based on actual operation in the application.
• VCC pin peripheral circuit
Figure 16 shows the VCC pin peripheral circuit. The reference
value of C2 is generally 10 to 47 μF (refer to Startup Operation
section, because the startup time is determined by the value of
C2).
In actual power supply circuits, there are cases in which the
VCC pin voltage fluctuates in proportion to the output current,
IOUT (see figure 17), and the Overvoltage Protection function
(OVP) on the VCC pin may be activated. This happens because
C2 is charged to a peak voltage on the auxiliary winding D,
which is caused by the transient surge voltage coupled from the
primary-side winding when the power MOSFET turns off.
STR-A6000-AN, Rev. 4.1
VCC
pin voltage
Without R2
With R2
Output Current, I OUT
Figure 17. VCC versus IOUT with and without resistor R2
SANKEN ELECTRIC CO., LTD.
15
For alleviating C2 peak charging, it is effective to add some
value R2, of several tenths of ohms to several ohms, in series
with D2 (see figure 16). The optimal value of R2 should be determined using a transformer matching what will be used in the
actual application, because the variation of the auxiliary winding
voltage is affected by the transformer structural design.
• Phase Compensation
VOUT
A typical phase compensation circuit with a secondary-side
shunt regulator (U51) is shown in figure 18.
The reference value of C52 is about 0.047 to 0.47 μF, and should
be adjusted based on actual operation in the application.
L51
D51
T1
R54
PC1
R51
R55
C51
C53
R52
S
• Transformer
C52 R53
Apply proper design margin to core temperature rise due to core
loss and copper loss.
U51
Because the switching currents contain high frequency currents,
the skin effect may become a consideration.
Choose a suitable wire gauge in consideration of the RMS current and a current density of about 3 to 4 A/mm2.
R56
GND
Figure 18. Peripheral circuit around secondary-side shunt regulator (U51)
If measures to further reduce temperature are still necessary, the
following should be considered to increase the total surface area
of the wiring:
▫ Increase the number of wires in parallel.
Margin tape
Fluctuation of the VCC pin voltage by IOUT worsens in the
following cases, requiring a transformer designer to pay close
attention to the placement of the auxiliary winding D:
▫ Poor coupling between the primary-side and secondary-side
windings (this causes high surge voltage and is seen in a design with low output voltage and high output current)
▫ Poor coupling between the auxiliary winding D and the
secondary-side stabilized output winding where the output line
voltage is controlled constant by the output voltage feedback
(this is susceptible to surge voltage)
In order to reduce the influence of surge voltage on the VCC
pin, figure 19 shows winding structural examples which take
into consideration the placement of the auxiliary winding D:
▫ Winding structural example (a): Separating the auxiliary winding D from the primary-side windings P1 and P2. P1 and P2
are windings divided the primary-side winding into two.
▫ Winding structural example (b): Placing the auxiliary winding
D within the secondary-side stabilized output winding, S1, in
order to improve the coupling of those windings. S1 is a stabilized output winding of secondary-side windings, controlled to
constant voltage.
STR-A6000-AN, Rev. 4.1
P1 S1 P2 S2 D
Margin tape
Winding structural example (a)
Margin tape
Bobbin
▫ Thicken the wire gauge.
Bobbin
▫ Use litz wire.
P1 S1
D S2 S1 P2
Margin tape
Winding structural example (b)
P1, P2㧦 Primary main winding
D㧦 Primary auxiliary winding
S1㧦 Secondary stabilized output winding
S2㧦 Secondary output winding
Figure 19. Winding structural examples
SANKEN ELECTRIC CO., LTD.
16
This is the main trace containing switching currents, and thus
it should be as wide and short as possible. If the IC and C1
are distant from each other, placing a capacitor such as a film
or ceramic capacitor (about 0.1 μF and with proper voltage
rating) close to the transformer or the IC is recommended to
reduce impedance of the high frequency current loop.
(2) GND Trace Layout: GND pin to C2 (negative pin) to T1
(winding D) to R2 to D2 to C2 (positive pin) to VCC pin
This is the trace for supplying power to the IC, and thus it
should be as wide and short as possible. If the IC and C2 are
distant from each other, placing a capacitor such as a film or
ceramic capacitor (about 0.1 to 1.0 μF) close to the VCC pin
and the GND pin is recommended.
(3) ROCP Trace Layout
ROCP should be placed as close as possible to the S/OCP pin.
The connection between the power ground of the main trace
and the IC ground should be at a single point ground (point A
in figure 21) which is close to the base of ROCP , to reduce
common impedance, and to avoid interference from switching currents to the control part in the IC.
• Secondary-side Rectifier-Smoothing Circuit Trace Layout: T1
(winding S) to D51 to C51
PCB Trace Layout and Component Placement
PCB circuit trace design and component layout significantly
affect operation, EMI noise, and power dissipation. Therefore,
pay extra attention to these designs. In general, trace loops shown
in figure 20 where high frequency currents flow should be wide,
short, and small to reduce line impedance. In addition, earth
ground traces affect radiated EMI noise, and wide, short traces
should be taken into account.
Switch -mode power supplies consist of current traces with high
frequency and high voltage, and thus trace design and component layouts should be done to comply with all safety guidelines.
Furthermore, because the power MOSFET has a positive thermal coefficient of RDS(ON) , consider it when preparing a thermal
design.
Figure 21 shows a circuit layout design example.
• IC Peripheral Circuit
(1) S/OCP pin Trace Layout: S/OCP pin to ROCP to C1 to T1
(winding P) to D/ST pin
This is the trace of the rectifier-smoothing loop, carrying the
switching current, and thus it should be as wide and short as
possible. If this trace is thin and long, inductance resulting from
the loop may increase surge voltage at turning off the power
MOSFET. Proper rectifier-smoothing trace layout helps to increase margin against the power MOSFET breakdown voltage,
and reduces stress on the clamp snubber circuit and losses in it.
Figure 20. High frequency current loops (hatched areas)
D51
T1
R1
C5
P
C1
C51
D1
S
D2
8
D/ST D/ST
C4
R2
5
7
NC
C2
VCC
D
U1
Main power circuit trace
S/OCP BR GND FB/OLP
1
2
3
4
C3
GND trace for the IC
PC1
ROCP
A
C9
Figure 21. Peripheral circuit example around the IC
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
17
Pattern Layout Example
The following show the PCB pattern layout example and the
schematic of dual outputs circuit with STR-A6000 series.
Figure 22. PCB circuit trace layout example
1
F1
L1
D1
D2 TH1
D4
D3
C1
L2
T1
L51
D51
3 VOUT1
t°
C3
3
C4
R1
C55
R4
R54
R51
C2
J1
R55
R52
C51
D5
JW1
P1
PC 1
C53
S1
R53
JW2
D6
8
R6
D/ST
NC
VCC
C5
4
GND
1
OUT2
2
GND
D
JW51
D52
U1
C8
R56
5
7
D/ST
R8
U51
R2
R57
C52
JW52
STR-A6000
R60
R9
S/OCP
BR
1
2
JW3
R7
C7
R3
C56
GND FB/OLP
3
C6
R58
C54
4
R61
R59
CP1
C9
CN51
Figure 23. Circuit schematic for PCB circuit trace layout
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
18
Reference Design of Power Supply
As an example, the following show circuit schematic, bill of materials, a power supply specification, and transformer specification.
F1
1
L1
D1
D2
D4
D3
L2
TH1
C1
T1
L51
D51
t°
3
R1
C3
R4
C4
C2
S1
C51
D5
R51
C55
C53
R53
S2
R8
7
D/ST
D/ST
NC
VCC
4
GND
R56
D
C5
U1
STR-A6000
S/OCP
BR
1
2
GND FB/OLP
3
C7
R7
U51
R57
C52
5
8
C8
R9
R2
5V/1.5A
R55
R52
PC1
P1
D6
3
R54
4
C6
CP1
R3
C9
Figure 24. Reference design schematic
Bill of Materials
Symbol
Part type
Ratingsa
F1
Fuse
L1c
CM inductor
Recommended
Sanken Parts
Symbol
Part type
Ratingsa
250 VAC, 3 A
R4b
Metal oxide
330 kΩ, 1 W
3.3 mH
R7
General
330 kΩ
L2c
Inductor
470 μH
R8b
General
2.2 MΩ
TH1c
NTC thermistor
Short
R9b
General
2.2 MΩ
D1
General
600 V, 1 A
EM01A
PC1
Photocoupler
PC123 or equivalent
D2
General
600 V, 1 A
EM01A
U1
IC
–
D3
General
600 V, 1 A
EM01A
T1
Transformer
See the specification
D4
General
600 V, 1 A
EM01A
L51
Inductor
5 μH
D5
Fast recovery
1000 V, 0.5 A
EG01C
D51
Schottky
90 V, 4 A
D6
Fast recovery
200 V, 1 A
AL01Z
C51
Electrolytic
680 μF, 10 V
C1c
Film, X2
0.047 μF, 275 V
C52c
Ceramic
0.1 μF, 50 V
C2
Electrolytic
10 μF, 400 V
C53
Electrolytic
330 μF, 10 V
C3
Electrolytic
10 μF, 400 V
C55c
Ceramic
1000 pF, 1 kV
C4
Ceramic
1000 pF, 630 V
R51
General
220 Ω
C5
Electrolytic
22 μF, 50 V
R52
General
1.5 kΩ
C6c
Ceramic
0.01 μF
R53c
General
22 kΩ
C7c
Ceramic
1000 pF
R54
General, 1%
Short
C8c
Ceramic
Open
R55
General, 1%
10 kΩ
C9
Ceramic, Y1
2200 pF, 250 V
R56
General, 1%
10 kΩ
R1c
General
Open
R57
General
Open
R2c
General
4.7 Ω
U51
Shunt regulator
VREF = 2.5 V, TL431 or
equivalent
R3
General
1.5 Ω, 1/2 W
Recommended
Sanken Parts
STR-A6059H
FMB-G19L
aUnless
otherwise specified, the voltage rating of capacitor is 50 V or less and the power rating of resistor is 1/8 W or less.
bResistors applied high DC voltage and of high resistance are recommended to select resistors designed against electromigration or use
combinations of resistors in series for that to reduce each applied voltage, according to the requirement of the application.
cIt is necessary to be adjusted based on actual operation in the application.
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
19
Power Supply Specification
IC
STR-A6059H
Input Voltage
85 to 265 VAC
Maximum Output Power
7.5 W (max)
Output Voltage
5V
Output Current
1.5 A (max)
Transformer specification
▫ Primary inductance, LP : 704 μH
▫ Core size: EI-16
▫ AL-value: 87 nH/N2 (Center gap of about 0.26 mm)
▫ Winding specification
Location
Symbol
Number of Turns
(T)
Wire
(mm)
Configuration
Primary winding
P1
73
2UEW-Ø0.18
2 layers, solenoid winding
Auxiliary winding
D
17
2UEW-Ø0.18×2
Solenoid winding
Output winding
S1-1
6
TEX-Ø0.3×2
Solenoid winding
Output winding
S1-2
6
TEX-Ø0.3×2
Solenoid winding
D
S1-2
S1-1
P1
Bobbin
Cross-section view
STR-A6000-AN, Rev. 4.1
VDC
P1
5V
S1-1
GND
D/ST
VCC
D
S1-2
GND
٨ mark shows the start point of winding
SANKEN ELECTRIC CO., LTD.
20
IMPORTANT NOTES
• The contents in this document are subject to changes, for improvement and other purposes, without notice. Make sure that this is the
latest revision of the document before use.
• Application and operation examples described in this document are quoted for the sole purpose of reference for the use of the products herein and Sanken can assume no responsibility for any infringement of industrial property rights, intellectual property rights or
any other rights of Sanken or any third party which may result from its use. Unless otherwise agreed in writing by Sanken, Sanken
makes no warranties of any kind, whether express or implied, as to the products, including product merchantability, and fitness for a
particular purpose and special environment, and the information, including its accuracy, usefulness, and reliability, included in this
document.
• Although Sanken undertakes to enhance the quality and reliability of its products, the occurrence of failure and defect of semiconductor products at a certain rate is inevitable. Users of Sanken products are requested to take, at their own risk, preventative measures
including safety design of the equipment or systems against any possible injury, death, fires or damages to the society due to device
failure or malfunction.
• Sanken products listed in this document are designed and intended for the use as components in general purpose electronic equipment or apparatus (home appliances, office equipment, telecommunication equipment, measuring equipment, etc.).
When considering the use of Sanken products in the applications where higher reliability is required (transportation equipment and
its control systems, traffic signal control systems or equipment, fire/crime alarm systems, various safety devices, etc.), and whenever
long life expectancy is required even in general purpose electronic equipment or apparatus, please contact your nearest Sanken sales
representative to discuss, prior to the use of the products herein.
The use of Sanken products without the written consent of Sanken in the applications where extremely high reliability is required
(aerospace equipment, nuclear power control systems, life support systems, etc.) is strictly prohibited.
• When using the products specified herein by either (i) combining other products or materials therewith or (ii) physically, chemically
or otherwise processing or treating the products, please duly consider all possible risks that may result from all such uses in advance
and proceed therewith at your own responsibility.
• Anti radioactive ray design is not considered for the products listed herein.
• Sanken assumes no responsibility for any troubles, such as dropping products caused during transportation out of Sanken’s distribution network.
• The contents in this document must not be transcribed or copied without Sanken’s written consent.
STR-A6000-AN, Rev. 4.1
SANKEN ELECTRIC CO., LTD.
21
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