Primary Side Regulation
Off-Line PWM Controllers with Integrated Power MOSFET
STR5A100D Series
General Descriptions
Package
The STR5A100D series is power IC with primary side
regulation for switching power supplies, incorporating a
sense MOSFET and a current mode PWM controller IC.
Employing the Primary Side Regulation, the product
achieves power supply systems with few external
components. Including a startup circuit and a standby
function in the controller, the product achieves the low
standby power by the automatic switching between the
PWM operation in normal operation and the
burst-oscillation under light load conditions. The rich set
of protection features helps to realize low component
counts, and high performance-to-cost power supply.
DIP8
Typical Application Circuit
D50
T1
C3
COMP
VCC
2
7
S/GND
6
S/GND
5
S/GND
4
Lineup
Electrical Characteristics
VD/ST(max.) = 730 V
fOSC(AVG)(typ.) = 65 kHz
RDS(ON) (max.)
Products
IDLIM(H)
STR5A162D
24.6 Ω
0.285 A
STR5A164D
13 Ω
0.41 A
Output Power, POUT*
Adapter
Products
AC85
Open frame
AC230V
~265V
AC230V
AC85
~265V
STR5A162D
4W
3.5 W
5W
4.5 W
STR5A164D
6.0 W
5.5 W
8.5 W
7W
* The EI-16 core of transformer is assumed. The output power is
actual continues power that is measured at 50 °C ambient. The
peak output power can be 120 to 140 % of the value stated here.
Core size, ON Duty, and thermal design affect the output power.
It may be less than the value stated here.
Applications
L1
VAC
C2
8
Not to scale
Primary Side Regulation
Constant Voltage (CV), Constant Current (CC) Control
Auto Standby Function
No Load Power Consumption < 30mW
Operation Mode
・Normal Operation -------------------------- PWM Mode
・Light Load Operation ----------------------Green-Mode
・Standby ------------------------- Burst Oscillation Mode
Build-in Startup Circuit
(reducing power consumption at standby operation,
shortening the startup time)
Current Mode Type PWM Control
Random Switching Function
Leading Edge Blanking Function
Soft Start Function (reducing the stress of power
MOSFET and secondary side rectifier diode at startup)
Protections
Overcurrent Protection (OCP) ------------ Pulse-by-Pulse
Overvoltage Protection (OVP) ------------- Auto-Restart
Thermal Shutdown Protection (TSD) ----- Auto-Restart
C1
1
D/ST
Features
BR1
FB
VOUT
(+)
R1
R51
C51
White Goods
Other SMPS
P
R2
U1
S/GND
D1
D/ST
C52
R52
4
NC
5
S1
S/GND
6
C6
C5
R7
7
D2
S/GND
VCC
COMP
FB
R6
(-)
2
R3
8
STR5A100D
D
1
R4
C4
R5
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
1
STR5A100D Series
Contents
General Descriptions ----------------------------------------------------------------------- 1
1. Absolute Maximum Ratings --------------------------------------------------------- 3
2. Recommended Operating Conditions --------------------------------------------- 3
3. Electrical Characteristics ------------------------------------------------------------ 3
4. Performance Curves ------------------------------------------------------------------ 5
5. Functional Block Diagram ----------------------------------------------------------- 6
6. Pin Configuration Definitions ------------------------------------------------------- 6
7. Typical Application Circuit --------------------------------------------------------- 6
8. Physical Dimensions------------------------------------------------------------------- 7
9. Marking Diagram --------------------------------------------------------------------- 7
10. Operational Description -------------------------------------------------------------- 8
10.1 Startup Operation ------------------------------------------------------------ 8
10.2 Undervoltage Lockout (UVLO) ------------------------------------------- 8
10.3 Auxiliary Winding------------------------------------------------------------ 8
10.4 Soft Start Function ----------------------------------------------------------- 9
10.5 Primary Side Regulation (PSR) ------------------------------------------- 9
10.6 Constant Voltage (CV) Control ------------------------------------------ 10
10.7 Constant Current (CC) Control ------------------------------------------ 10
10.8 Leading Edge Blanking Function ---------------------------------------- 11
10.9 Random Switching Function ---------------------------------------------- 11
10.10 Auto Standby Function ----------------------------------------------------- 11
10.11 Overcurrent Protection Function (OCP) ------------------------------- 11
10.12 Overvoltage Protection (OVP) -------------------------------------------- 12
10.13 Thermal Shutdown Protection (TSD) ----------------------------------- 12
11. Design Notes --------------------------------------------------------------------------- 13
11.1 External Components------------------------------------------------------- 13
11.2 PCB Trace Layout and Component Placement ----------------------- 15
12. Pattern Layout Example ------------------------------------------------------------ 17
13. Reference Design of Power Supply ----------------------------------------------- 18
Important Notes ---------------------------------------------------------------------------- 20
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
2
STR5A100D Series
1.
Absolute Maximum Ratings
The polarity value for current specifies a sink as "+," and a source as "−," referencing the IC.
Unless otherwise specified, TA is 25 °C, 5 pin = 6 pin = 7 pin
Parameter
Symbol
Test Conditions
Pins
Rating
Units
1–5
7.0
V
1–5
− 10
mA
Remarks
FB Pin Voltage
VFB
FB Pin Source Current
IFB
VCC Pin Voltage
VCC
2–5
− 0.3 to 32
V
D/ST Pin Voltage
VD/ST
4–5
− 0.3 to 730
V
Drain Peak Current
IDP
− 0.2 to 0.69
A
5A162D
− 0.2 to 0.97
A
5A164D
COMP Pin Voltage
VCOMP
8–5
− 0.3 to 7.0
V
–
1.53
W
Power Dissipation
(1)
PD
Single pulse
Positive: Single pulse
Negative: Within 2μs
of pulse width
(2)
4–5
Operating Ambient Temperature
TOP
–
− 40 to 125
°C
Storage Temperature
Tstg
–
− 40 to 125
°C
Junction Temperature
Tj
–
150
°C
(1)
(2)
2.
Refer to MOSFET Temperature versus Power Dissipation Curve
When embedding this hybrid IC onto the printed circuit board (cupper area in a 15mm×15mm)
Recommended Operating Conditions
Recommended operating conditions means the operation conditions maintained normal function shown in
electrical characteristics.
Parameter
Symbol
Min.
Max.
Units
Remarks
D/ST Pin Voltage in Operation
VD/ST(OP)
− 0.3
584
V
VCC Pin Voltage in Operation
VCC(OP)
11
27
V
3.
Electrical Characteristics
The polarity value for current specifies a sink as "+," and a source as "−," referencing the IC.
Unless otherwise specified, TA is 25 °C, VD/ST = 10 V, pin = 6 pin = 7 pin
Parameter
Symbol
Test
Conditions
Pins
Min.
Typ.
Max.
Units
Remarks
Power Supply Startup Operation
Operation Start Voltage
VCC(ON)
2–5
13.6
15.0
16.6
V
Operation Stop Voltage
VCC(OFF)
2–5
7.3
8.1
8.9
V
Circuit Current in Operation
Startup Circuit Operation
Voltage
ICC(ON)
VCC = 12 V
2–5
–
–
2.5
mA
VSTARTUP
VCC = 13.5 V
4–5
19
29
39
V
Startup Current
ISTARTUP
VCC = 13.5 V
VD/ST = 100 V
2–5
− 3.7
− 2.1
− 0.9
mA
fOSC(AVG)
VCOMP = 5.5 V
4–5
57
65
73
kHz
4–5
–
2.8
–
kHz
PWM Operation
Average Switching Frequency
Frequency Modulation Deviation
Δf
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
3
STR5A100D Series
Parameter
Symbol
Test
Conditions
Pins
Min.
Typ.
Max.
Units
1–5
2.45
2.50
2.55
V
1–5
− 2.4
− 0.8
−
μA
tFBMS
1–5
–
–
2.2
μs
Standby Operation Threshold
Voltage
VSTBOP
8–5
1.7
2.3
3.1
V
5A162D
1.3
2.0
2.7
V
5A164D
Standby Operation Cycle
TSTBOP
4–5
–
1.3
–
ms
Maximum ON Duty
DMAX
4–5
50
57
64
%
Feedback Reference Voltage
VFB(REF)
Feedback Current
VFB(OP)
Minimum Sampling Time
VFB = 2.4 V
Remarks
COMP Pin Sink Current
ICOMP(SI)
VCOMP = 5.5 V
8–5
–
4.5
–
μA
COMP Pin Source Current
ICOMP(SO)
VCOMP = 2.5 V
8–5
–
– 4.5
–
μA
gm
VFB = 2.4V
to 2.6V
–
–
16
–
μS
tBW
–
–
250
–
ns
DDPC
–
–
27
–
%
Drain Current Limit
(ON Duty ≥ 27 %)
IDLIM(H)
4–5
0.250
0.285
0.320
A
5A162D
0.36
0.41
0.46
A
5A164D
Drain Current Limit
(ON Duty = 0 %)
IDLIM(L)
4–5
0.210
0.242
0.280
A
5A162D
0.29
0.34
0.39
A
5A164D
VCC(OVP)
2–5
27.5
29.3
31.3
V
tCCD
4–5
–
90
–
ms
Tj(TSD)
–
135
–
–
°C
Tj(TSDHYS)
–
–
70
–
°C
Tj = 125 °C
VD/ST = 584 V
4–5
–
–
50
µA
ID = 28.5 mA
4–5
–
21.0
24.6
Ω
5A162D
ID = 41 mA
4–5
–
11
13
Ω
5A164D
4–5
–
–
250
ns
–
–
20
°C/W
–
–
24
°C/W
Error Amplifier Conductance
Protection Function
Leading Edge Blanking Time
(1)
Drain Current Limit
Compensation ON Duty(1)
OVP Threshold Voltage
Constant Current Control Delay
Time
Thermal Shutdown Operating
Temperature(1)
Thermal Shutdown Hysteresis(1)
Power MOSFET
Drain Leakage Current
On Resistance
Switching Time
IDSS
RDS(ON)
tf
Thermal Characteristics
Thermal Resistance Junction to
θj-F
–
Frame (1)(2)
Thermal Resistance Junction to
θj-C
–
Case(1)(3)
(1)
Design assurance
(2)
Frame temperature (TF) measured at the root of the 6 pin (S/GND)
(3)
Case temperature (TC) measured at the center of the case top surface
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
4
STR5A100D Series
Performance Curves
Transient Thermal Resistance
θj-C (°C)
4.
1.6
1.2
1
0.8
0.6
Time (s)
0.4
Figure 4-2 STR5A162D Transient Thermal Resistance Curve
0.2
0
0
25
50
75
100
125
150
Ambient Temperature, TA (°C)
Figure 4-3 Ambient Temperature versus
Power Dissipation Curve
Transient Thermal Resistance
θj-C (°C)
Allowable Power Dissipation, PD (W)
1.53
1.4
Time (s)
Figure 4-2 STR5A164D Transient Thermal Resistance Curve
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
5
STR5A100D Series
5.
Functional Block Diagram
2
VCC
D/ST
STARTUP
4
UVLO
OVP
REG
PROTECTION
TSD
PWM
OSC
DRV
S Q
R
OCP
1
FB
S/H
Feedback
Control
E/A
S/GND
LEB
5, 6, 7
COMP
8
6.
Pin Configuration Definitions
FB
1
VCC
2
D/ST
7.
4
8
COMP
Pin
1
Name
FB
7
S/GND
2
VCC
6
S/GND
–
D/ST
5
S/GND
3
4
5
6
7
8
Descriptions
Input of constant voltage control signal
Power supply voltage input for Control Part and
input of Overvoltage Protection (OVP) signal
(Pin removed)
MOSFET Drain and input of startup current
S/GND
MOSFET Source and ground
COMP
Input of phase compensation
Typical Application Circuit
BR1
L1
D50
T1
VAC
C3
R1
R51
C1
VOUT
(+)
C51
P
C2
R2
U1
S/GND
D1
D/ST
C52
R52
4
NC
5
S1
S/GND
6
C6
C5
R7
7
D2
S/GND
VCC
R6
(-)
2
R3
8
COMP
FB
STR5A100D
D
1
R4
C4
R5
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
6
STR5A100D Series
8.
Physical Dimensions
DIP8
9.4±0.3
5
1
4
6.5±0.2
8
1.52 +0.3
-0.05
7.6 TYP
3.3±0.2
4.2±0.3
3.4±0.1
7.5±0.5
+0.3
1.0-0.05
0.2 +0
5 .1
-0.
05
2.54 TYP
０～１５°
０～１５°
0.89 TYP
0.5±0.1
NOTES:
1) Unit : mm
2) Pb-free. Device composition compliant with the RoHS directive
9.
Marking Diagram
8
5A1××D
Part Number
SKYMD
Lot Number
Y = Last digit of year (0 to 9)
1
M = Month (1 to 9,O,N or D)
D = Period of days (1 to 3)
1 : 1st to 10th
2 : 11th to 20th
3 : 21st to 31st
Sanken control number
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
7
STR5A100D Series
10. Operational Description
10.2 Undervoltage Lockout (UVLO)
All of the parameter values used in these descriptions
are typical values, 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).
Figure 10-2 shows the relationship of VCC pin
voltage and circuit current ICC. When VCC pin voltage
increases to VCC(ON) = 15.0 V, the control circuit starts
switching operation and the circuit current ICC increases.
When VCC pin voltage decreases to VCC(OFF) = 8.1 V,
the control circuit stops operation by UVLO
(Undervoltage Lockout) circuit, and reverts to the state
before startup.
10.1 Startup Operation
Figure 10-1 shows the VCC pin peripheral circuit.
The IC incorporates the startup circuit. The circuit is
connected to D/ST pin. When D/ST pin voltage reaches
to Startup Circuit Operation Voltage V STARTUP = 29 V,
the startup circuit starts operation.
During the startup process, the constant current,
ISTARTUP = − 2.1 mA, charges C4 at VCC pin. When
VCC pin voltage increases to VCC(ON) = 15.0 V, the
control circuit starts switching operation. After
switching operation begins, the startup circuit turns off
automatically so that its current consumption becomes
zero.
The approximate startup time of IC, tSTART, is
calculated as follows:
t START C4
Circuit current, ICC
ICC（ON）
Stop
VCC（OFF）
Start
VCC（ON） VCC pin
voltage
Figure 10-2 Relationship between
VCC pin voltage and ICC
VCC( ON )－VCC( INT )
(1)
I STARTUP
10.3 Auxiliary Winding
where,
tSTART: Startup time of IC in second
VCC(INT) : Initial voltage on VCC pin in V
L1
T1
VAC
C1
4
D/ST
VCC
2
D2
U1
C2
P
R6
R3
Figure 10-3 shows VCC voltage behavior during the
startup period. When VCC pin voltage increases to
VCC(ON) = 15.0 V at startup, the IC starts the operation.
Then circuit current increases and VCC pin voltage
decreases. Since the Operation Stop Voltage
VCC(OFF) = 8.1 V is low, the auxiliary winding voltage
reaches to setting value before VCC pin voltage
decreases to VCC(OFF). Thus control circuit continues the
operation. The voltage from the auxiliary winding D in
Figure 10-1 becomes a power source to the control
circuit in operation. The approximate value of auxiliary
winding voltage is about 12 V to 16 V, taking account of
the winding turns of D winding so that VCC pin voltage
satisfies Equation (2) within the specification of input
and output voltage variation of power supply.
D
VCC pin voltage IC starts operation
C4
S/GND
5,6,7
R4
VD
R5
FB 1
Startup success
Target operating
voltage
VCC(ON)
Increase with rising of
output voltage
VCC(OFF)
Startup failure
Figure 10-1 VCC pin peripheral circuit
Time
Figure 10-3 VCC pin voltage during startup period
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
8
STR5A100D Series
VCC(OFF ) (max .) VCC VCC(OVP ) (min .)
⇒ 8.9 (V) < VCC < 27.5 (V)
(2)
In addition, the auxiliary winding voltage VD is
determined as follows:
VD
ND
× ( VOUT VF )
NS
(3)
where,
ND: Turns of auxiliary winding of transformer
NS: Turns of secondary side winding of transformer
VOUT: Output voltage
VF: Forward drop voltage of secondary side rectifier
diode D50
When VCC pin voltage reaches to VCC(OFF) and a
startup failure occurs as shown in Figure 10-3, increase
the C4 value. Since the larger capacitance causes the
longer startup time of IC, it is necessary to check and
adjust the startup process based on actual operation in
the application.
10.4 Soft Start Function
Figure 10-4 shows the behavior of VCC pin voltage
and drain current during the startup period.
The IC activates the soft start circuitry during the
startup period. Soft start time is fixed to around 4.5 ms.
During the soft start period, over current threshold is
increased step-wisely (7 steps). This function reduces
the voltage and the current stress of MOSFET and
secondary side rectifier diode.
VCC pin
voltage
Startup of IC Startup of SMPS
Normal opertion
tSTART
VCC(ON)
VCC(OFF)
Time
D/ST pin
current, ID
Soft start period
approximately 4.5 ms (fixed)
IDLIM(H)
tLIM < tCCD
Time
Since the Leading Edge Blanking Function (refer to
Section 10.8) is deactivated during the soft start period,
there is the case that ON time is less than the leading
edge blanking time, tBW = 250 ns.
After the soft start period, D/ST pin current, ID, is
limited by the Drain Current Limit, IDLIM(H), until the
output voltage increases to the target operating voltage.
This period is given as tLIM.
In case tLIM is longer than the CC Operation Delay
Time, tCCD , the output power is limited by the CC mode.
Thus, it is necessary to adjust the value of output
capacitor and the turn ratio of auxiliary winding D so
that the tLIM is less than tCCD = 90 ms.
10.5 Primary Side Regulation (PSR)
The IC is for Primary Side Regulation (PSR). In PSR,
the auxiliary winding voltage is divided by resistors (R3,
R4 and R5) and is induced into FB pin as shown in
Figure 10-5. The constant voltage output control is
achieved by using FB pin voltage.
Figure 10-6 shows the detection timing of auxiliary
winding voltage VD. When the power MOSFET turns
off, the energy stored in transformer is provided to
secondary side of the circuit. Then the current IDO flows
through the secondary side rectifier diode. After the
transfer of energy, power MOSFET continues off state
and the free oscillation of VD starts. During the free
oscillation period, IDO becomes zero.
The feedback signal is generated by sampling the
shoulder of VD waveform (point A in Figure 10-6). Thus
the effect of VF is minimized.
The Minimum Sampling Time, tFBMS, is 2.2 μs (max.).
Since the sampling time becomes the shortest in burst
oscillation mode (refer to Section 10.10) , the sampling
time should be more than tFBMS (shown in Figure 10-6).
The ideal waveform of auxiliary winding voltage V D
is shown in Figure 10-6. The VD waveform depends on
the waveform of the primary winding P voltage. In order
to reduce the transient surge of VD waveform, a clamp
snubber circuit of a capacitor-resistor-diode (CRD)
combination should be added on the primary winding P
as shown in Figure 10-5.
In order to improve the accuracy of VD waveform
sampling, the IC has sampling delay time, tFBD, so that
the surge component of the waveform at the turning off
of power MOSFET is not sampled.
In case that the width of the surge component is longer
than tFBD = 0.9 μs, the width should be adjusted to be
under tFBD. It is achieved by adjusting the value of R1
and C3 and by reducing the peak and width of the surge
component.
In addition, in order to realize the ideal VD waveform
shown in Figure 10-6, add the resistor R2 in series with
the diode of CRD circuit to suppress the ringing of the
waveform.
Figure 10-4 VCC and ID behavior during startup
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
9
STR5A100D Series
CRD clamp snubber
L1
VAC
C1
C3
C2
R1
P
R2
D1
VDS
4
D/ST
D2 R6
2
R3
U1
VD
D
R4
S/GND
5~8
FB
output voltage when the output load becomes light.
Accordingly, the output voltage of internal error
amplifier (target voltage VSC) decreases. As a result,
the peak value of VROCP is controlled to be lower so
that the peak of the drain current decreases. This
control prevents the output voltage from increasing.
Heavy Load Conditions
The control circuit performs reverse operations to the
former. The target voltage VSC of internal comparator
becomes higher and the peak drain current increases.
This control prevents the output voltage from
decreasing.
D/ST
U1
1
4
PWM
Control
R5
PSR circuit
Feedback
Control
VSC
Figure 10-5 FB pin peripheral circuit
+
-
VCC 2
VROCP
ROCP
tON
tON
tOFF
R6
C4
S/GND
FB
5,6,7
1
IDpk
Secondary side
rectifier diode
current, IDO
Auxiliary winding
voltage, VD
VD
I DOpk I Dpk
VError
N
D VF
NS
R4
R5
NP
NS
Figure 10-7 FB pin peripheral circuit
tFBMS
tFBD
ND
VOUT VF
NS
ND
VOUT
NS
D
R3
+
-
E/A
S/H
D/ST pin current, ID
D2
FB comp
-
VSC
+
VROCP
FB comparator
Voltage on both side of ROCP
0
A
Sampling set point
Drain current, ID
ΔVF：Diode Dropped Voltage
Figure 10-6 Detection timing of
auxiliary winding voltage
Figure 10-8 Drain current ID and FB comparator
in steady operation
10.6 Constant Voltage (CV) Control
10.7 Constant Current (CC) Control
The IC achieves the constant voltage (CV) control of
the power supply output by using the peak-current-mode
control method, which enhances the response speed and
provides the stable operation.
The IC controls the peak value of the voltage of build-in
sense resistor (VROCP) to be close to target voltage (VSC),
comparing VROCP with VSC by internal FB comparator.
Feedback Control circuit receives the sampling voltage
which is the reversed auxiliary winding voltage by using
error amplifier (refer to Figure 10-7 and Figure 10-8)
The IC operates in Constant Current (CC) Control
when output current reaches to constant load and the
state continues for more than the Constant Current
Control Delay Time, tCCD = 90 ms. In case the IC is in
discontinuous operation, the CV/CC characteristic is as
shown in Figure 10-9.
When output current reaches to constant load,
MOSFET drain current is limited to the Drain Current
Limit IDLIM(H). When the output voltage becomes low,
the CC Control is maintained by lowering the oscillation
frequency fOSC. When the output voltage becomes low,
the FB pin voltage becomes low. When FB pin voltage
Light Load Conditions
The FB pin voltage increases with the increase of the
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
10
STR5A100D Series
decreases to about 1.6 V or less, the IC is stops
oscillation and restarts. The IC repeats the intermittent
oscillation operation until the FB pin voltage keeps
about 1.6 V or more after the output voltage increases.
Output Voltage
VOUT
L P I DLIM f OSC
2VOUT
2
I OUT( PK )
CV Mode
CC Mode
frequency about 23 kHz. In light load, the number of
minimum switching times is two times in TSTBOP (refer
to Figure 10-11)
Since the oscillator of burst oscillation cycle setting
and the oscillator of switching oscillation frequency
setting are not synchronized each other, the switching
frequency may be high at near the Standby Operation
Threshold Voltage, VSTBOP.
Switching
frequency
fOSC
65kHz
Normal
operation
About
23kHz
Burst oscillation
Output Current IOUT
Green mode
Burst cycle is 1.3ms
Standby power
Figure 10-9 CV/CC characteristics
Output power, PO
Figure 10-10 Relationship between PO and fOSC
10.8 Leading Edge Blanking Function
The IC uses the peak-current-mode control method
for the constant voltage control of output.
In peak-current-mode control method, there is a case
that the power MOSFET turns off due to unexpected
response of FB comparator or overcurrent protection
circuit (OCP) to the steep surge current in turning on a
power MOSFET.
In order to prevent this operation, Leading Edge
Blanking Time, tBW = 250 ns is built-in.
In the period of tBW, the IC does not respond to the
surge voltage in turning on the power MOSFET.
10.9 Random Switching Function
The IC modulates its switching frequency randomly
by superposing the modulating frequency on fOSC(AVG) in
normal operation. This function reduces the conduction
noise compared to others without this function, and
simplifies noise filtering of the input lines of power
supply.
10.10 Auto Standby Function
Auto Standby Function automatically changes the
oscillation mode to green mode or burst oscillation mode,
when the output load becomes lower, the drain current
ID decreases and the oscillation frequency becomes
lower gradually (Green Mode) as shown in Figure
10-10.
In order to reduce the switching loss, the number of
switching is reduced in green mode and the switching
operation is stopped during a constant period in burst
oscillation mode.
The burst oscillation mode operates by the Standby
Operation Cycle, TSTBOP = 1.3 ms and the switching
ID
TSTBOP = 1.3 ms
About 23 kHz
Time
Figure 10-11 Switching waveform at burst oscillation
10.11 Overcurrent Protection Function (OCP)
Overcurrent Protection Function (OCP) detects each
drain peak current level of a power MOSFET on
pulse-by-pulse basis, and limits the output power when
the current level reaches to Drain Current Limit.
When this OCP operation continues for more than the
Constant Current Control Delay Time, tCCD = 90 ms,
Constant Current (CC) control is activated (refer to
Section 10.7).
Input Compensation Function
ICs with PWM control usually have some propagation
delay time. The steeper the slope of the actual drain
current at a high AC input voltage is, the larger the
actual drain peak current is, compared to the Drain
Current Limit. Thus, the peak current has some variation
depending on the AC input voltage in the drain current
limitation state.
In order to reduce the variation of peak current in the
drain current limitation state, the IC incorporates a
built-in Input Compensation function.
The Input Compensation function superposes a signal
with a constant slope (Figure 10-12) into the internal
current detection signal and varies the internal threshold
voltage.
When AC input voltage is low (ON Duty is broad),
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
11
STR5A100D Series
the Drain Current Limit after compensation increases.
The difference of peak drain current become small
compared with the case where the AC input voltage is
high (ON Duty is narrow).
The compensation signal depends on ON Duty. The
relation between the ON Duty and the drain current limit
after compensation IDLIM' is expressed as Equation (4).
When ON Duty is broader than 27 %, the drain current
limit becomes a constant value IDLIM(H).
I DLIM '
I DLIM( H ) I DLIM( L)
27(%)
Duty I DLIM( L )
(4)
where,
Duty: MOSFET ON Duty (%)
IDLIM(H): Drain current limit (ON Duty ≥ 27 %)
IDLIM(L): Drain current limit (ON Duty = 0 %)
STR5A162D
0.285 A
0.242 A
STR5A164D
0.41 A
0.34 A
Drain Current Limit after
compensation, IDLIM'
IDLIM(L)
IDLIM(H)
IDLIM(L)
0
0%
27%
ON Duty
VOUT NORMAL
VOUT(OVP)
VCC NORMAL
29.3
(5)
where,
VOUT(NORMAL): Output voltage in normal operation
VCC(NORMAL): VCC pin voltage in normal operation
10.13 Thermal Shutdown Protection (TSD)
IDLIM(H)
DDPC
In case the VCC pin voltage is provided by using
auxiliary winding of transformer, the overvoltage
conditions such as FB pin open can be detected because
the VCC pin voltage is proportional to FB pin voltage.
The approximate value of output voltage VOUT(OVP) in
OVP condition is calculated by using Equation (5).
DMAX
57%
Figure 10-12 Relationship between ON Duty and Drain
Current Limit after compensation
Figure 10-13 shows the TSD operational waveforms.
When the temperature of control circuit increases to
Tj(TSD) = 135 °C or more, Thermal Shutdown function
(TSD) is activated, and the IC stops switching operation.
After that, VCC pin voltage decreases. When the VCC
pin voltage decreases to about 9.4 V, the bias assist
function is activated and VCC pin voltage is kept to over
the VCC(OFF).
When the temperature reduces to less than
Tj(TSD)−Tj(TSD)HYS, the Bias Assist function is disabled
and the VCC pin voltage decreases to VCC(OFF). At that
time, the IC stops operation by the UVLO circuit and
reverts to the state before startup. After that, the startup
circuit is activated, the VCC pin voltage increases to
VCC(ON), and the IC starts switching operation again. In
this way, the intermittent operation by TSD and UVLO
is repeated while there is an excess thermal condition.
When the fault condition is removed, the IC returns to
normal operation automatically.
Junction Temperature,
Tj
10.12 Overvoltage Protection (OVP)
When a voltage between VCC pin and S/GND
terminal increases to VCC(OVP) = 29.3 V or more, OVP
Function is activated and stops switching operation.
When OVP Function is activated, VCC pin voltage
decreases to Operation Stop Voltage VCC(OFF) = 8.1 V.
After that, the IC reverts to the initial state by UVLO
(Undervoltage Lockout) circuit, and the IC starts
operation when VCC pin voltage increases to
VCC(ON) = 15.0 V by Startup Current. Thus the
intermittent operation by UVLO is repeated in OVP
condition.
This intermittent operation reduces the stress of parts
such as power MOSFET and secondary side rectifier
diode. In addition, this operation reduces power
consumption because the switching period in this
intermittent operation is short compared with oscillation
stop period. When the abnormal condition is removed,
the IC returns to normal operation automatically.
Tj(TSD)
Tj(TSD)−Tj(TSD)HYS
Bias assist
function
ON
ON
OFF
OFF
VCC pin voltage
VCC(ON)
VCC(BIAS)
VCC(OFF)
Drain current
ID
Figure 10-13 TSD operational waveforms
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
12
STR5A100D Series
VD is calculated as follows:
11. Design Notes
VFW
11.1 External Components
Take care to use properly rated, including derating as
necessary and proper type of components.
CRD clamp snubber
L1
VAC
P
C3
C1
D/ST
VCC
2
D50
VOUT
(+)
R1
R2
C52
R52
D1
where,
VIN(AC) : Input voltage
ND : Turns of D winding
NP : Turns of P winding
(-)
D2
R6
(7)
Auxiliary
winding
voltage, VD
R51 C51
C2
4
U1
S1
ND
VIN(AC) 2
NP
0
D
VREV
VFW
R3
C4
FB 1
S/GND
5~8
R4
VD
R5
Figure 11-2 The auxiliary winding voltage waveform
Figure 11-1 Peripheral circuit of FB pin and VCC pin
Output Electrolytic Capacitor
Apply proper derating to ripple current, voltage,
and temperature rise. Use of high ripple current and
low impedance types, designed for switch mode
power supplies, is recommended.
FB Pin Peripheral Circuit and CRD Clamp
Snubber
Figure 11-1 shows the FB pin peripheral circuit.
The auxiliary winding voltage, VD is divided by
resistors (R3, R4 and R5) and induced into FB pin.
The FB pin voltage is controlled to be Feedback
Reference Voltage, VFB(REF) = 2.50 V.
The value of R5 is about 3.3 kΩ to 10 kΩ.
The value of R3 and R4 are calculated as follows:
ND
VOUT VF VFB ( REF)
N
R3 R 4 S
VFB ( REF)
I FB ( OP )
R5
(6)
where,
ND: Turns of auxiliary winding of transformer
NS: Turns of secondary side winding of transformer
VOUT: Output voltage
VF: Forward drop voltage of secondary side rectifier
diode D50
VFB(REF): Feedback Reference Voltage, 2.50 V
IFB(OP): Feedback Current, − 0.8 μA
In addition, the negative voltage is input to FB pin. As
shown in Figure 11-2, the negative voltage, VFW, of
The absolute maximum rating of FB Pin Source
Current, IFB is − 10 mA. The value of R3 and R4 are
chosen so that the FB pin source current, IFB(FW),
satisfies Equation (8) considered about surge.
I FB(FW)
VFW
R3 R 4
N D VIN( AC )
2
5mA
N P R3 R 4
(8)
There, the maximum input voltage substitutes in
VIN(AC).
R3, R4 and R5 should be adjusted in actual operation
condition.
The IC generates the feedback signal by sampled VD
waveform that is FB pin input signal. In order to
improve the accuracy of VD waveform sampling, it is
necessary to realize the ideal VD waveform for
reducing the peak and width of the surge component
and suppressing the ringing. Because the VD
waveform depends on the waveform of the primary
winding P voltage, a clamp snubber circuit should be
added on the primary winding P. The method of
setting the value of the clamp snubber circuit is shown
in Section 10.5.
In order to maintain the sampling accuracy during
light load operation, an auxiliary switch diode
SARS05 should be used as D1 where the approximate
value of R2 is 220 Ω to 470 Ω. R2 should be adjusted
to obtain proper VD waveform in actual operation
condition.
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
13
STR5A100D Series
VCC Pin Peripheral Circuit
The reference value of C4 (see Figure 11-1) is
generally from 4.7 µF to 2.2 μF. The startup time is
determined by the value of C4 (refer to Section
10.1 Startup Operation).
In actual power supply circuits, there are cases in
which the VCC pin voltage fluctuates in proportion
to the output current, IOUT (see Figure 11-3), and
the Overvoltage Protection function (OVP) on the
VCC pin may be activated. This happens because
C4 is charged to a peak voltage on the auxiliary
winding D, which is caused by the transient surge
voltage coupled from the primary winding when
the power MOSFET turns off.
For alleviating C4 peak charging, it is effective to
add some value R6, of several tenths of ohms to
several ohms, in series with D2 (see Figure 11-1).
The optimal value of R6 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.
Without R6
VCC pin voltage
With R6
Output current IOUT
value of both C6 and R7 are 680 pF to 2200 pF and
680 kΩ, respectively. These should be adjusted on
actual operation.
Because the internal impedance of COMP pin is
high, the measurement of COMP pin waveform by
using the oscilloscope needs a caution.
Especially in light load condition, the probe of the
oscilloscope may affect the control of IC. Thus the
voltage-follower (buffer) circuit with high
impedance Op Amp should be used for the
measurement of COMP pin.
D/ST Pin
The internal power MOSFET connected to D/ST
pin (see Figure 11-1) is permanently damaged
when the D/ST pin voltage and the current exceed
the Absolute Maximum Ratings. Therefore, as
shown in Figure 11-5, The D/ST pin voltage is
tuned to be less than about 90 % of the Absolute
Maximum Ratings (657 V) in all condition of
actual operation, and the value of transformer and
components should be selected based on actual
operation in the application.
And the D/ST pin voltage in normal operation is
tuned to be the Recommended Operating
Conditions, VD/ST(OP) < 584 V.
The fast recovery diodes are recommended for
using as D2 and D51. The way of setting the value
of the clamp snubber circuit is shown in Section
10.5.
D/ST pin voltage
< 657 V
Figure 11-3 Variation of VCC pin voltage and power
supply output current with / without R6 resistor
VD/ST(OP) < 584 V
COMP Pin Peripheral Circuit
Figure 11-4shows the COMP pin peripheral circuit.
U1
S/GND
8
5,6,7
+
-
R7
C6
Time
COMP
C5
Probe
Buffer circuit
Figure 11-4 COMP pin peripheral circuit
The capacitor C5 between COMP pin and S/GND
pin performs for high frequency noise reduction
and phase compensation.
C5 should be connected to both COMP pin and
S/GND pin as short as possible. The recommended
value of C5 is 100 pF to 680 pF. The approximate
Figure 11-5 D/ST pin voltage waveform
Bleeder Resistance
Since the IC employs the primary side regulation,
the IC continues burst oscillation operation at light
load in order to detect the state of secondary side.
In case the power supply is used under light load
condition (input power is 25 mW or less at
maximum input voltage) or no load condition, in
order to prevent the increase of output voltage, the
bleeder resistance, R52, is connected to both ends
of the output capacitor, C52, as shown in Figure
11-1.
The value of R52 should be selected based on
actual operation in the application after the R52
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
14
STR5A100D Series
In the following cases, the surge of VCC pin
voltage becomes high.
▫ The surge voltage of primary main winding, P, is
high (low output voltage and high output current
power supply designs)
▫ The winding structure of auxiliary winding, D, is
susceptible to the noise of winding P.
When the surge voltage of winding D is high, the
VCC pin voltage increases and the Overvoltage
Protection function (OVP) may be activated. In
transformer design, the following should be
considered;
▫ The coupling of the winding P and the secondary
output winding S should be maximized to reduce the
leakage inductance.
▫ The coupling of the winding D and the winding S
should be maximized.
▫ The coupling of the winding D and the winding P
should be minimized.
In the case of multi-output power supply, the
coupling of the secondary-side stabilized output
winding, S1, and the others (S2, S3…) should be
maximized to improve the line-regulation of those
outputs.
Figure 11-6 shows the winding structural examples
of two outputs.
Winding structural example (a):
S1 is sandwiched between P1 and P2 to
maximize the coupling of them for surge
reduction of P1 and P2.
D is placed far from P1 and P2 to minimize the
coupling to the primary for the surge reduction of
D.
Winding structural example (b)
P1 and P2 are placed close to S1 to maximize the
coupling of S1 for surge reduction of P1 and P2.
D and S2 are sandwiched by S1 to maximize the
coupling of D and S1, and that of S1 and S2.
Margin tape
Bobbin
Transformer
Apply proper design margin to core temperature rise
by core loss and copper loss.
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 4 to 6 A/mm2.
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.
▫ Use litz wires.
▫ Thicken the wire gauge.
This structure reduces the surge of D, and
improves the line-regulation of outputs.
P1 S1 P2 S2 D
Margin tape
Winding structural example (a)
Margin tape
Bobbin
which loss of R52 becomes about 10 mW is
connected.
P1 S1
D S2 S1 P2
Margin tape
Winding structural example (b)
Figure 11-6 Winding structural examples
11.2 PCB Trace Layout and Component
Placement
Since the PCB circuit trace design and the component
layout significantly affects operation, EMI noise, and
power dissipation, the high frequency PCB trace should
be low impedance with small loop and wide trace.
In addition, the ground traces affect radiated EMI noise,
and wide, short traces should be taken into account.
Figure 11-7 shows the circuit design example.
(1) Main Circuit Trace Layout:
This is the main trace containing switching currents,
and thus it should be as wide trace and small loop as
possible.
If C2 and the IC are distant from each other, placing
a capacitor such as film 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) Control Ground Trace Layout
Since the operation of IC may be affected from the
large current of the main trace that flows in control
ground trace, the control ground trace should be
connected at a single point grounding of point A as
close to the S/GND pin as possible.
(3) VCC Trace Layout:
This is the trace for supplying power to the IC, and
thus it should be as small loop as possible. If C4 and
the IC are distant from each other, placing a
capacitor such as film capacitor Cf (about 0.1 μF to
1.0 μF) close to the VCC pin and the S/GND pin is
recommended.
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
15
STR5A100D Series
(4) COMP Trace Layout
C5, C6 and R7 are connected to COMP pin for phase
compensation. These capacitors and resistor should
be placed to shorten the trace between COMP pin
and S/GND pin. In order to stabilize the operation of
IC, a dedicated trace to S/GND pin is recommended.
(7) Thermal Considerations
Because the power MOSFET has a positive thermal
coefficient of RDS(ON), consider it in thermal design.
Since the copper area under the IC and the S/GND
trace act as a heatsink, its traces should be as wide as
possible.
(5) FB Trace Layout
The auxiliary winding voltage is divided by resistors
and is induced to FB pin. In order to achieve the
accurate primary side regulation, the trace between
the resistors and FB pin should be as short as
possible.
(6) Secondary Rectifier Smoothing Circuit Trace
Layout:
This is the trace of the rectifier smoothing loop,
carrying the switching current, and thus it should be
as wide trace and small loop 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.
(6)Main trace of secondary side should be
wide trace and small loop
(1) Main trace should be wide trace and small loop
F1
BR1
L1
D50
T1
VAC
C3
C1
C2
R1
C8
R51 C51
P
R2
U1
S/GND
D/ST
R52
S
4
NC
5
(7)Trace of S/GND pin should be wide
for heat release
C52
D1
S/GND
6
R6
D2
(2)GND trace for IC should be
connected at a single point
S/GND
VCC
COMP
FB
2
7
C6
C5
R7
R3
8
1
STR5A1××D
C4
R5
(4)The components connected to COMP pin should be short, and these
components connected to S/GND pin should be dedicated trace.
D
R4
(5) The components connected to FB
pin should be short
C7
(3) Loop of the power supply should be small
Figure 11-7 Example of peripheral circuit around the IC
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
16
STR5A100D Series
12. Pattern Layout Example
The following show the PCB pattern layout example and the circuit schematic with STR5A100D series.The above
circuit symbols correspond to these of Figure 12-1.
Slit width
Top view
Bottom view
Figure 12-1 PCB circuit trace layout example
F1
BR1
L1
5 T1
VAC
C3
C1
R51
U1
C51
S1
D1
D/ST
C52 C54
4
R52
3
NC
5
VOUT
(+)
P
R2
S/GND
D50
R1
C8
C2
7
S/GND
6
C6
C5
R7
7
D2
S/GND
VCC
R6
2
(-)
2
R3
8
COMP
FB
STR5A100D
9
D
1
R4
C4
C7
R5
1
Figure 12-2 Circuit schematic for PCB circuit trace layout
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
17
STR5A100D Series
13. Reference Design of Power Supply
As an example, the following show the power supply specification, the circuit schematic, the bill of materials, and
the transformer specification.
Power supply specification
IC
Input voltage
Maximum output power
Output voltage
Output current
STR5A164D
AC 85 V to AC 265 V
5 W (max.)
5V
1 A (max.)
Circuit schematic
F1
BR1
L1
D50
T1
VAC
C3
C1
R1
R51
C8
C2
R2
S/GND
C51
P
U1
S1
D1
D/ST
C52
R52
4
NC
5
5V/1A
S/GND
6
C6
C5
R7
7
D2
S/GND
VCC
COMP
FB
R6
2
R3
8
STR5A100D
D
1
R4
C4
R5
C7
Bill of materials
Symbol
BR1
Part type
General
F1
Fuse
600 V, 1 A
AC 250 V, 1 A
Recommended
Symbol
Part type
Sanken Parts
(2)
R4
Chip
Ratings(1)
R5
Chip
4.7 kΩ
Chip
0Ω
Chip
680 kΩ
800 V, 1 A
CM inductor
330 μH
R6
C1
Electrolytic
400 V, 4.7 μF
R7
(2)
C2
Electrolytic
400 V, 4.7 μF
D1
General
C3
Ceramic, chip
630 V, 1000 pF
D2
Fast recovery, chip FRD 200 V, 1 A
C4
Electrolytic
50 V, 10 µF
U1
IC
Transformer
C5
(2)
Ceramic, chip
330 pF
T1
C6
(2)
Ceramic, chip
1000 pF
D50
C7
(2)
Ceramic, chip
Open
C51
C8
(2)
Ceramic, chip
Open
C52
R1
(3)
Metal oxide, chip
470 kΩ
R51
R2
R3
(2)
Chip
270 Ω
Chip
3.9 kΩ
R52*
(2)
(2)
Recommended
Sanken Parts
15 kΩ
(2)
(2)
L1*
(2)
Ratings(1)
SARS05
Schottky
STR5A164D
See
the specification
60 V, 3 A
SJPB-L6
Ceramic, chip
50 V, 2200 pF
Electrolytic
10V, 470µF
Chip
22 Ω
Chip
2.7 kΩ
(1)
Unless otherwise specified, the voltage rating of capacitor is 50 V or less and the power rating of resistor is 1/8 W or less.
(2)
It is necessary to be adjusted based on actual operation in the application.
(3)
Resistors 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.
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
18
STR5A100D Series
Transformer specification
▫ Primary inductance, LP : 1.7 mH
▫ Core size : EI-16
▫ AL-value： 118 nH/N2 (Center gap of about 0.3 mm)
▫ Winding specification
Number of Wire diameter
Winding
Symbol
turns (T)
(mm)
Primary winding 1
P1
80
φ 0.16
Primary winding 2
P2
40
φ 0.16
Auxiliary winding
D
18
φ 0.16 × 2
Output winding 1
S1
8
φ 0.3 × 2
Output winding 2
S2
8
φ 0.3 × 2
5 pin
P2
S2
D
S1
Construction
Two layers,
solenoid winding
Single-layer,
solenoid winding
Single-layer,
solenoid winding
Single-layer,
solenoid winding
Single-layer,
solenoid winding
VDC
5V
P1
Wire
Enameled Copper Wire
Enameled Copper Wire
Enameled Copper Wire
Triple insulated wire
Triple insulated wire
7 pin
S1
9 pin
P2
3 pin
D/ST
2 pin VCC
P1
Bobbin
1 pin GND
S2
D
●:Start
Cross-section view
at this pin
Figure 13-1 Example of transformer structure
Notes:
1) Coupling between D winding and S1 winding should be adjusted and be improved by applying the solid
winding construction in D winding, for example.
2) The peak value of drain current ID in normal operation is determined by LP value. Since the slope of ID is
expressed as VDS/LP, the smaller the LP value, the steeper the slope of ID becomes. Thus the peak value of
drain current becomes high as shown in Figure 13-2. The IC limits the peak current by drain current limit
IDLIM (Overcurrent state). If LP value becomes small by variation, there is the case that the system is in
overcurrent state. Then the designed output power cannot be achieved. Thus the L P value should be
determined after the confirmation in actual operation using minimum LP value within the variation, where
the peak current value should be less than IDLIM(MIN) in minimum input voltage of power supply.
Drain current,
ID
IDLIM
Limited by IDLIM
（Overcurrent state）
LP (min.)
LP (typ.)
LP (max.)
Time
Figure 13-2 Relation between LP and drain current ID
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
19
STR5A100D Series
Important Notes
All data, illustrations, graphs, tables and any other information included in this document (the “Information”) as to Sanken’s
products listed herein (the “Sanken Products”) are current as of the date this document is issued. The Information is subject to any
change without notice due to improvement of the Sanken Products, etc. Please make sure to confirm with a Sanken sales
representative that the contents set forth in this document reflect the latest revisions before use.
The Sanken Products are intended for use as components of general purpose electronic equipment or apparatus (such as home
appliances, office equipment, telecommunication equipment, measuring equipment, etc.). Prior to use of the Sanken Products,
please put your signature, or affix your name and seal, on the specification documents of the Sanken Products and return them to
Sanken. When considering use of the Sanken Products for any applications that require higher reliability (such as transportation
equipment and its control systems, traffic signal control systems or equipment, disaster/crime alarm systems, various safety
devices, etc.), you must contact a Sanken sales representative to discuss the suitability of such use and put your signature, or affix
your name and seal, on the specification documents of the Sanken Products and return them to Sanken, prior to the use of the
Sanken Products. The Sanken Products are not intended for use in any applications that require extremely high reliability such as:
aerospace equipment; nuclear power control systems; and medical equipment or systems, whose failure or malfunction may result
in death or serious injury to people, i.e., medical devices in Class III or a higher class as defined by relevant laws of Japan
(collectively, the “Specific Applications”). Sanken assumes no liability or responsibility whatsoever for any and all damages and
losses that may be suffered by you, users or any third party, resulting from the use of the Sanken Products in the Specific
Applications or in manner not in compliance with the instructions set forth herein.
In the event of using the Sanken Products by either (i) combining other products or materials or both therewith or (ii) physically,
chemically or otherwise processing or treating or both the same, you must duly consider all possible risks that may result from all
such uses in advance and proceed therewith at your own responsibility.
Although Sanken is making efforts to enhance the quality and reliability of its products, it is impossible to completely avoid the
occurrence of any failure or defect or both in semiconductor products at a certain rate. You must take, at your own responsibility,
preventative measures including using a sufficient safety design and confirming safety of any equipment or systems in/for which
the Sanken Products are used, upon due consideration of a failure occurrence rate and derating, etc., in order not to cause any
human injury or death, fire accident or social harm which may result from any failure or malfunction of the Sanken Products.
Please refer to the relevant specification documents and Sanken’s official website in relation to derating.
No anti-radioactive ray design has been adopted for the Sanken Products.
The circuit constant, operation examples, circuit examples, pattern layout examples, design examples, recommended examples, all
information and evaluation results based thereon, etc., described in this document are presented for the sole purpose of reference of
use of the Sanken Products.
Sanken assumes no responsibility whatsoever for any and all damages and losses that may be suffered by you, users or any third
party, or any possible infringement of any and all property rights including intellectual property rights and any other rights of you,
users or any third party, resulting from the Information.
No information in this document can be transcribed or copied or both without Sanken’s prior written consent.
Regarding the Information, no license, express, implied or otherwise, is granted hereby under any intellectual property rights and
any other rights of Sanken.
Unless otherwise agreed in writing between Sanken and you, Sanken makes no warranty of any kind, whether express or implied,
including, without limitation, any warranty (i) as to the quality or performance of the Sanken Products (such as implied warranty
of merchantability, and implied warranty of fitness for a particular purpose or special environment), (ii) that any Sanken Product is
delivered free of claims of third parties by way of infringement or the like, (iii) that may arise from course of performance, course
of dealing or usage of trade, and (iv) as to the Information (including its accuracy, usefulness, and reliability).
In the event of using the Sanken Products, you must use the same after carefully examining all applicable environmental laws and
regulations that regulate the inclusion or use or both of any particular controlled substances, including, but not limited to, the EU
RoHS Directive, so as to be in strict compliance with such applicable laws and regulations.
You must not use the Sanken Products or the Information for the purpose of any military applications or use, including but not
limited to the development of weapons of mass destruction. In the event of exporting the Sanken Products or the Information, or
providing them for non-residents, you must comply with all applicable export control laws and regulations in each country
including the U.S. Export Administration Regulations (EAR) and the Foreign Exchange and Foreign Trade Act of Japan, and
follow the procedures required by such applicable laws and regulations.
Sanken assumes no responsibility for any troubles, which may occur during the transportation of the Sanken Products including
the falling thereof, out of Sanken’s distribution network.
Although Sanken has prepared this document with its due care to pursue the accuracy thereof, Sanken does not warrant that it is
error free and Sanken assumes no liability whatsoever for any and all damages and losses which may be suffered by you resulting
from any possible errors or omissions in connection with the Information.
Please refer to our official website in relation to general instructions and directions for using the Sanken Products, and refer to the
relevant specification documents in relation to particular precautions when using the Sanken Products.
All rights and title in and to any specific trademark or tradename belong to Sanken and such original right holder(s).
DSGN-CEZ-16003
STR5A100D-DSE Rev.1.5
SANKEN ELECTRIC CO., LTD.
Aug. 21, 2018
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2012
20
工商网监
湘ICP备2023018690号
