Off-Line PWM Controllers with Integrated Power MOSFET
STR-A6000MZ/HZ Series
Data Sheet
Description
Package
The STR-A6000MZ/HZ series are power ICs for
switching power supplies, incorporating a power
MOSFET and a current mode PWM controller IC.
The low standby power is accomplished by the
automatic switching between the PWM operation in
normal operation and the burst-oscillation under light
load conditions. The product achieves high costperformance power supply systems with few external
components.
DIP8
Not to scale
Selection Guide
Features
• Electrical Characteristics
• Current Mode Type PWM Control
• Brown-In and Brown-Out Function
• Soft Start Function
• Auto Standby Function
STR-A606×MZ
MOSFET
VDSS(min.)
700 V
Frequency
fOSC(AVG)
67 kHz
STR-A606×HZ
700 V
100 kHz
Part Number
No Load Power Consumption < 25mW
• Operation Mode
Normal Operation ---------------------------- PWM Mode
Standby -------------------------- Burst Oscillation Mode
• Random Switching Function
• Slope Compensation Function
• Leading Edge Blanking Function
• Bias Assist Function
• Protections
・Two Types of Overcurrent Protection (OCP): Pulseby-Pulse, built-in compensation circuit to minimize
OCP point variation on AC input voltage
・Overload Protection with timer (OLP): Auto-restart
・Overvoltage Protection (OVP): Auto-restart
・Thermal Shutdown (TSD) with hysteresis: Autorestart
• MOSFET ON Resistance and Output Power, POUT*
Part Number
RDS(ON)
(max.)
fOSC(AVG) = 67 kHz
STR-A6069MZ
BR1
L51
D51
T1
PC1
P
STR-A6063MZ
D/ST D/ST
RA
C5
S
R52
U51
VCC
C2
R56
(-)
D
U1
STR-A6000×Z
RB
S/OCP BR GND FB/OLP
1
RC
2
ROCP
3
4
C4
C3
24 W
26 W
17 W
14 W
19.5
W
31 W
21 W
37.5 W
26 W
fOSC(AVG) = 100 kHz
STR-A6069HZ
6.0 Ω
17 W
STR-A6061HZ 3.95 Ω 20.5 W
2.3 Ω
25 W
11 W
30 W
15 W
35 W
20 W
40 W
19.5
W
23.5
W
28 W
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
C53
C52 R53
R2
5
NC
2.3 Ω
10 W
R51
R55
C51
D1
D2
VOUT
(+)
R54
R1
C6
C1
7
15 W
* The output power is actual continues power that is measured at 50 °C
VAC
8
6.0 Ω
STR-A6061MZ 3.95 Ω 18.5 W
STR-A6063HZ
Typical Application
POUT
POUT
(Adapter)
(Open frame)
AC85
AC85
AC230V
AC230V
~265V
~265V
• White goods
• Office Automation Equipment
• Audio Visual Equipment
• Industrial Equipment
• Other SMPS
PC1
CY
TC_STR-A6000xZ_1_R2
STR-A6000MZ/HZ-DSE Rev.1.4
SANKEN ELECTRIC CO., LTD.
Jan. 13, 2022
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2014
1
STR-A6000MZ/HZ Series
Contents
Description ----------------------------------------------------------------------------------- 1
Contents--------------------------------------------------------------------------------------- 2
1. Absolute Maximum Ratings --------------------------------------------------------- 3
2. Electrical Characteristics ------------------------------------------------------------ 4
3. Performance Curves ------------------------------------------------------------------ 5
3.1
Derating Curves --------------------------------------------------------------- 5
3.2
MOSFET Safe Operating Area Curves ---------------------------------- 6
3.3
Ambient Temperature versus Power Dissipation Curve ------------- 6
3.4
Transient Thermal Resistance Curves ----------------------------------- 7
4. Block Diagram ------------------------------------------------------------------------- 8
5. Pin Configuration Definitions ------------------------------------------------------- 8
6. Typical Application ------------------------------------------------------------------- 9
7. Physical Dimension ------------------------------------------------------------------- 10
8. Marking Diagram -------------------------------------------------------------------- 10
9. Operational Description ------------------------------------------------------------- 11
9.1
Startup Operation ----------------------------------------------------------- 11
9.2
Undervoltage Lockout (UVLO) ------------------------------------------- 12
9.3
Bias Assist Function --------------------------------------------------------- 12
9.4
Soft Start Function ---------------------------------------------------------- 12
9.5
Constant Output Voltage Control ---------------------------------------- 13
9.6
Leading Edge Blanking Function ---------------------------------------- 14
9.7
Random Switching Function ---------------------------------------------- 14
9.8
Automatic Standby Mode Function-------------------------------------- 14
9.9
Brown-In and Brown-Out Function ------------------------------------- 14
9.10 Overcurrent Protection (OCP) ------------------------------------------- 16
9.11 Overload Protection (OLP) ------------------------------------------------ 17
9.12 Overvoltage Protection (OVP) -------------------------------------------- 17
9.13 Thermal Shutdown (TSD) ------------------------------------------------- 18
10. Design Notes --------------------------------------------------------------------------- 18
10.1 External Components ------------------------------------------------------- 18
10.2 PCB Trace Layout and Component Placement ----------------------- 20
11. Pattern Layout Example ------------------------------------------------------------ 22
12. Reference Design of Power Supply ----------------------------------------------- 23
Important Notes ---------------------------------------------------------------------------- 26
STR-A6000MZ/HZ-DSE Rev.1.4
SANKEN ELECTRIC CO., LTD.
Jan. 13, 2022
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2014
2
STR-A6000MZ/HZ 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 = 25 °C, 7 pin = 8 pin
Parameter
Symbol
Test
Conditions
Pins
Rating
Units
1.8
Drain Peak Current
(1)
Maximum Switching Current
IDPEAK
(2)
IDMAX
Single pulse
TA =
− 40 ~ 125 °C
8−1
8−1
ILPEAK=1.8A
Avalanche Energy
(3)(4)
EAS
ILPEAK=1.78A
8−1
2.5
A6069MZ/HZ
A
A6063MZ/HZ
1.8
A6069MZ/HZ
2.5
A
A6063MZ/HZ
24
A6069MZ/HZ
36
mJ
A6061MZ/HZ
A6063MZ/HZ
1−3
− 2 to 6
V
BR Pin Voltage
VBR
2−3
− 0.3 to 7.5
V
BR Pin Sink Current
IBR
2−3
1.0
mA
FB/OLP Pin Voltage
VFB
4−3
− 0.3 to 14
V
FB/OLP Pin Sink Current
IFB
4−3
1.0
mA
VCC Pin Voltage
VCC
5−3
32
V
D/ST Pin Voltage
VD/ST
8−3
− 1 to VDSS
V
8−1
1.35
W
(6)
A6061MZ/HZ
4.0
VS/OCP
S/OCP Pin Voltage
A6061MZ/HZ
4.0
53
ILPEAK=2.15A
Notes
MOSFET Power Dissipation(5)
PD1
Control Part Power Dissipation
PD2
5−3
1.2
W
Operating Ambient Temperature
TOP
−
− 40 to 125
°C
Storage Temperature
Tstg
−
− 40 to 125
°C
Channel Temperature
Tch
−
150
°C
(1)
Refer to 3.2MOSFET Safe Operating Area Curves
The Maximum Switching Current is the drain current determined by the drive voltage of the IC and threshold voltage
of the MOSFET, VGS(th).
(3)
Refer to Figure 3-2 Avalanche Energy Derating Coefficient Curve
(4)
Single pulse, VDD = 99 V, L = 20 mH
(5)
Refer to 3.3 TA-PD1Curve
(6)
When embedding this hybrid IC onto the printed circuit board (copper area in a 15 mm × 15 mm)
(2)
STR-A6000MZ/HZ-DSE Rev.1.4
SANKEN ELECTRIC CO., LTD.
Jan. 13, 2022
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2014
3
STR-A6000MZ/HZ Series
2.
Electrical Characteristics
• The polarity value for current specifies a sink as "+," and a source as "−," referencing the IC.
• Unless otherwise specified, TA = 25 °C, VCC = 18 V, 7 pin = 8 pin
Parameter
Symbol
Test
Conditions
Pins
Min.
Typ.
Max.
Units
Notes
Power Supply Startup Operation
Operation Start Voltage
VCC(ON)
5−3
13.8
15.0
16.2
V
Operation Stop Voltage(*)
VCC(OFF)
5−3
7.6
8.5
9.2
V
5−3
−
1.5
2.5
mA
8–3
40
47
55
V
Circuit Current in Operation
Startup Circuit Operation
Voltage
Startup Current
Startup Current Biasing
Threshold Voltage
Normal Operation
Average Switching Frequency
Switching Frequency
Modulation Deviation
VCC = 12 V
VST(ON)
ICC(ST)
VCC = 13.5 V
5−3
− 4.5
− 2.5
− 1.2
mA
VCC(BIAS)
ICC = −500 µA
5−3
8.0
9.6
10.5
V
60
67
73
90
100
110
−
5.4
−
−
8.4
−
4−3
− 170
− 130
− 85
µA
fOSC(AVG)
8–3
Δf
8−3
A60××MZ
kHz
A60××HZ
A60××MZ
kHz
A60××HZ
Maximum Feedback Current
IFB(MAX)
Minimum Feedback Current
IFB(MIN)
4−3
− 21
− 13
−5
µA
Standby Operation
FB/OLP Pin Oscillation Stop
VFB(OFF)
Threshold Voltage
Brown-In / Brown-Out Function
4−3
1.06
1.16
1.26
V
Brown-In Threshold Voltage
VBR(IN)
2–3
5.43
5.60
5.77
V
VBR(OUT)
2−3
4.65
4.80
4.95
V
2−3
6.5
6.9
7.3
V
VBR(DIS)
2−3
0.4
0.6
0.8
V
DMAX
8−3
70
75
80
%
tBW
−
−
330
−
ns
−
−
17.3
−
DPC
−
25.8
−
Brown-Out Threshold Voltage
BR Pin Clamp Voltage
BR Function Disabling
Threshold Voltage
Protection
Maximum ON Duty
Leading Edge Blanking Time
OCP Compensation Coefficient
OCP Compensation ON Duty
OCP Threshold Voltage at Zero
ON Duty
OCP Threshold Voltage at 36%
ON Duty
OCP Threshold Voltage in
Leading Edge Blanking Time
(*)
ICC(ON)
VCC = 12 V
VBR(CLAMP) IBR = 100 µA
mV/μs
A60××MZ
A60××HZ
DDPC
−
−
36
−
%
VOCP(L)
1−3
0.735
0.795
0.855
V
VOCP(H)
1−3
0.843
0.888
0.933
V
VOCP(LEB)
1−3
−
1.69
−
V
VCC(BIAS) > VCC(OFF) always.
STR-A6000MZ/HZ-DSE Rev.1.4
SANKEN ELECTRIC CO., LTD.
Jan. 13, 2022
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2014
4
STR-A6000MZ/HZ Series
Parameter
Test
Conditions
Symbol
Pins
Min.
Typ.
Max.
Units
VFB(OLP)
4−3
6.8
7.3
7.8
V
tOLP
4−3
55
75
90
ms
ICC(OLP)
5−3
−
220
−
µA
VFB(CLAMP)
4−3
10.5
11.8
13.5
V
VCC(OVP)
5−3
27.0
29.1
31.2
V
Tj(TSD)
−
127
145
−
°C
Tj(TSD)HYS
−
−
80
−
°C
OLP Threshold Voltage
OLP Delay Time
OLP Operation Current
FB/OLP Pin Clamp Voltage
OVP Threshold Voltage
Thermal Shutdown Operating
Temperature
Thermal Shutdown Temperature
Hysteresis
MOSFET
Drain-to-Source Breakdown
Voltage
Drain Leakage Current
On-Resistance
VDSS
IDS = 300 µA
8−1
700
−
−
V
IDSS
VDS = 700 V
8−1
−
−
300
µA
−
−
6.0
Ω
−
−
3.95
Ω
−
−
2.3
Ω
RDS(ON)
Switching Time
IDS = 0.4 A
8−1
tf
8−1
−
−
250
ns
θch-C
−
−
−
22
°C/W
Notes
A6069MZ
/HZ
A6061MZ
/HZ
A6063MZ
/HZ
Thermal Resistance
Channel to Case
3.
3.1
Performance Curves
Derating Curves
100
EAS Temperature Derating
Coefficient (%)
Safe Operating Area
Temperature Derating Coefficient (%)
100
80
60
40
20
80
60
40
20
0
0
0
25
50
75
100
125
150
Channel Temperature, Tch (°C)
Figure 3-1 SOA Temperature
Derating Coefficient Curve
STR-A6000MZ/HZ-DSE Rev.1.4
SANKEN ELECTRIC CO., LTD.
Jan. 13, 2022
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2014
25
50
75
100
125
150
Channel Temperature, Tch (°C)
Figure 3-2 Avalanche Energy
Derating Coefficient Curve
5
STR-A6000MZ/HZ Series
3.2
MOSFET Safe Operating Area Curves
⚫ When the IC is used, the safe operating area curve should be multiplied by the temperature derating coefficient derived
from Figure 3-1.
⚫ The broken line in the safe operating area curve is the drain current curve limited by on-resistance.
⚫ Unless otherwise specified, TA = 25 °C, Single pulse
⚫ STR-A6061MZ/HZ
⚫ STR-A6063MZ/HZ
1
1ms
0.1
0.1ms
Drain Current, ID (A)
S_STR-A6061xZ_R1
Drain Current, ID (A)
0.1ms
1
1ms
S_STR-A6063xZ_R1
10
10
0.1
0.01
0.01
1
10
100
Drain-to-Source Voltage (V)
1000
1
10
100
Drain-to-Source Voltage (V)
1000
⚫ STR-A6069MZ/HZ
Drain Current, ID (A)
0.1ms
1
S_STR-A6069xZ_R1
10
1ms
0.1
0.01
1
10
100
1000
Drain-to-Source Voltage (V)
3.3
Ambient Temperature versus Power Dissipation Curve
1.4
PD1=1.35W
1.2
1
0.8
PD1_STR-A6000xZ_R2
Power Dissipation, PD1 (W)
1.6
0.6
0.4
0.2
0
0
25
50
75
100 125
Ambient Temperature, TA (°C )
150
STR-A6000MZ/HZ-DSE Rev.1.4
SANKEN ELECTRIC CO., LTD.
Jan. 13, 2022
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2014
6
STR-A6000MZ/HZ Series
3.4
Transient Thermal Resistance Curves
⚫ STR-A6061MZ/HZ
TR_STR-A6061xZ_R1
Transient Thermal Resistance
θch-c (°C/W)
100
10
1
0.1
0.01
1µ
10µ
100µ
1m
10m
100m
1s
10m
100m
1s
10m
100m
1s
Time (s)
⚫ STR-A6063MZ/HZ
TR_STR-A6063xZ_R1
Transient Thermal Resistance
θch-c (°C/W)
100
10
1
0.1
0.01
1µ
10µ
100µ
1m
Time (s)
⚫ STR-A6069MZ/HZ
TR_STR-A6069xZ_R1
Transient Thermal Resistance
θch-c (°C/W)
100
10
1
0.1
0.01
1µ
10µ
100µ
1m
Time (s)
STR-A6000MZ/HZ-DSE Rev.1.4
SANKEN ELECTRIC CO., LTD.
Jan. 13, 2022
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2014
7
STR-A6000MZ/HZ Series
4.
Block Diagram
VCC
5
Startup
UVLO
BR
2
REG
VREG
OVP
D/ST
7,8
TSD
Brown-in
Brown-out
DRV
PWM OSC
S Q
R
OCP
VREG
VCC
Drain peak current
compensation
OLP
Feedback
control
FB/OLP
4
LEB
S/OCP
1
GND
3
Slope
compensation
BD_STR-A6000xZ_R1
5.
Pin Configuration Definitions
S/OCP
1
8
D/ST
BR
2
7
D/ST
GND
3
6
FB/OLP
4
5
VCC
Pin
Name
1
S/OCP
2
BR
3
GND
4
FB/OLP
5
VCC
6
−
7
8
D/ST
Descriptions
Power MOSFET source and Overcurrent
Protection (OCP) signal input
Brown-In and Brown-Out detection voltage input
Ground
Constant voltage control signal input and
Overload Protection (OLP) signal input
Power supply voltage input for control part and
Overvoltage Protection (OVP) signal input
(Pin removed)
Power MOSFET drain and startup current input
STR-A6000MZ/HZ-DSE Rev.1.4
SANKEN ELECTRIC CO., LTD.
Jan. 13, 2022
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2014
8
STR-A6000MZ/HZ Series
6.
Typical Application
• The following drawings show circuits enabled and disabled the Brown-In/Brown-Out Function.
• The PCB traces the D/ST pins should be as wide as possible, in order to enhance thermal dissipation.
• In applications having a power supply specified such that the D/ST pin has large transient surge voltages, a clamp
snubber circuit of a capacitor-resistor-diode (CRD) combination should be added on the primary 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.
CRD Clamp snubber
BR1
VAC
VOUT
(+)
R54
R1
C6
RA
L51
D51
T1
PC1
C1
R51
P
R55
C51
D1
RB
D2
8
C5
NC
C53
C52 R53
R2
U51
5
7
D/ST D/ST
R52
S
VCC
R56
D
C2
(-)
U1
STR-A6000×Z
S/OCP BR GND FB/OLP
C（RC）
Damper snubber
1
RC
2
3
4
C4
C3
PC1
ROCP
CY
TC_STR-A6000xZ_2_R1
Figure 6-1
Typical application (enabled Brown-In/Brown-Out Function, DC line detection)
CRD clamp snubber
BR1
L51
D51
T1
VAC
VOUT
R54
R1
C6
PC1
C1
R51
P
R55
C51
D1
S
D2
8
D/ST D/ST
C5
NC
U51
VCC
C2
C53
C52 R53
R2
5
7
R52
R56
D
U1
GND
STR-A6000
S/OCP BR GND FB/OLP
C（RC）
damper snubber
1
2
3
4
C3
ROCP
PC1
CY
TC_STR-A6000xZ_3_R1
Figure 6-2
Typical application (disabled Brown-In/Brown-Out Function)
STR-A6000MZ/HZ-DSE Rev.1.4
SANKEN ELECTRIC CO., LTD.
Jan. 13, 2022
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2014
9
STR-A6000MZ/HZ Series
7.
Physical Dimension
• DIP8
NOTES:
1) Dimension is in millimeters.
2) Pb-free. Device composition compliant with the RoHS directive.
8.
Marking Diagram
8
Specific Device Code1 (See Table 8-1)
Specific Device Code2 (See Table 8-1)
S KY MD
1
Y is the last digit of the year of manufacture (0 to 9)
M is the month of the year (1 to 9, O, N, or D)
D is the period of days represented by:
1: the first 10 days of the month (1st to 10th)
2: the second 10 days of the month (11th to 20th)
3: the last 10–11 days of the month (21st to 31st)
Control Number
Table 8-1
Specific Device Code 1
A6069M
A6061M
A6063M
A6069H
A6061H
A6063H
Specific Device Code
Specific Device Code 2
Z
Z
Z
Z
Z
Z
STR-A6000MZ/HZ-DSE Rev.1.4
SANKEN ELECTRIC CO., LTD.
Jan. 13, 2022
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2014
Part Number
STR-A6069MZ
STR-A6061MZ
STR-A6063MZ
STR-A6069HZ
STR-A6061HZ
STR-A6063HZ
10
STR-A6000MZ/HZ Series
9.
Operational Description
9.1.2 With Brown-In / Brown-Out Function
• 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).
9.1
When BR pin voltage is more than VBR(DIS) = 0.6 V and
less than VBR(IN) = 5.60 V, the Bias Assist Function (refer
to Section 9.3) is disabled. Thus, VCC pin voltage repeats
increasing to VCC(ON) and decreasing to VCC(OFF) (shown in
Figure 9-3). When the BR pin voltage becomes VBR(IN) or
more, the IC starts switching operation.
BR1
Startup Operation
Figure 9-1 shows the circuit around the IC.
The IC incorporates the startup circuit. The circuit is
connected to the D/ST pin. When the D/ST pin voltage
reaches to Startup Circuit Operation Voltage, VST(ON) = 47
V, the startup circuit starts operation.
During the startup process, the constant current,
ICC(ST) = − 2.5 mA, charges C2 at the VCC pin. When the
VCC pin voltage increases to VCC(ON) = 15.0 V, the control
circuit starts operation. During the IC operation, the
voltage rectified the auxiliary winding voltage, V D, of
Figure 9-1 becomes a power source to the VCC pin. After
switching operation begins, the startup circuit turns off
automatically so that its current consumption becomes
zero.
The approximate value of auxiliary winding voltage is
about 15 V to 20 V, taking account of the winding turns of
D winding so that VCC pin voltage becomes Equation (1)
within the specification of input and output voltage
variation of power supply.
C1
7, 8
D/ST
U1
VCC
(1)
9.1.1 Without Brown-In / Brown-Out
Function (BR pin voltage is
VBR(DIS) = 0.6 V or less)
BR
2
GND
VCC ( ON )－VCC ( INT)
where,
tSTART : Startup time of the IC (s)
VCC(INT) : Initial voltage on the VCC pin (V)
R2
VD
D
3
Figure 9-1 VCC pin peripheral circuit
(Without Brown-In / Brown-Out Function)
VCC pin
voltage
VCC(ON)
Drain current,
ID
Figure 9-2 Startup operation
(Without Brown-In / Brown-Out Function)
VCC pin
voltage
When VCC pin voltage increases to VCC(ON), the IC
starts switching operation, As shown in Figure 9-2.
The startup time of the IC is determined by C2 capacitor
value. The approximate startup time tSTART (shown in
Figure 9-2) is calculated as follows:
I CC (ST )
D2
P
tSTART
The oscillation start timing of the IC depends on
Brown-In / Brown-Out Function (refer to Section 9.9).
t START = C2 ×
5
C2
VCC ( BIAS ) (max .) VCC VCC ( OVP ) (min .)
⇒10.5 (V) VCC 27.0 (V)
T1
VAC
(2)
tSTART
VCC(ON)
VCC(OFF)
BR pin
voltage
VBR(IN)
Drain current,
ID
Figure 9-3 Startup operation
(With Brown-In / Brown-Out Function)
STR-A6000MZ/HZ-DSE Rev.1.4
SANKEN ELECTRIC CO., LTD.
Jan. 13, 2022
https://www.sanken-ele.co.jp/en
© SANKEN ELECTRIC CO., LTD. 2014
11
STR-A6000MZ/HZ Series
9.2
Undervoltage Lockout (UVLO)
Figure 9-4 shows the relationship of VCC pin
voltage and circuit current ICC. When the VCC pin
voltage decreases to VCC(OFF) = 8.5 V, the control
circuit stops operation by the Undervoltage Lockout
(UVLO) circuit, and reverts to the state before
startup.
Circuit current, ICC
ICC（ON）
When the VCC pin voltage is decrease to VCC(OFF) = 8.5
V in startup operation, the IC stops switching operation
and a startup failure occurs.
When the output load is light at startup, the output
voltage may become more than the target voltage due to
the delay of feedback circuit. In this case, the FB pin
voltage is decreased by the feedback control. When the FB
pin voltage decreases to VFB(OFF) or less, the IC stops
switching operation and the VCC pin voltage decreases.
When the VCC pin voltage decreases to VCC(BIAS), the Bias
Assist Function is activated and the startup failure is
prevented.
VCC pin
voltage
Stop
Start
Startup success
IC starts operation
Target operating
voltage
Increase with rising of
output voltage
VCC(ON)
VCC(BIAS)
VCC（OFF）
VCC（ON） VCC pin
voltage
Bias assist period
VCC(OFF)
Startup failure
Time
Figure 9-4 Relationship between
VCC pin voltage and ICC
Figure 9-5
9.3
VCC pin voltage during startup period
Bias Assist Function
By the Bias Assist Function, the startup failure is
prevented.
When FB pin voltage is the FB/OLP Pin Oscillation
Stop Threshold Voltage, VFB(OFF)= 1.16 V or less and VCC
pin voltage decreases to the Startup Current Biasing
Threshold Voltage, VCC(BIAS) = 9.6 V, the Bias Assist
Function is activated.
When the Bias Assist Function is activated, the VCC
pin voltage is kept almost constant voltage, VCC(BIAS) by
providing the startup current, ICC(ST), from the startup
circuit. Thus, the VCC pin voltage is kept more than
VCC(OFF).
Since the startup failure is prevented by the Bias Assist
Function, the value of C2 connected to the VCC pin can
be small. Thus, the startup time and the response time of
the Overvoltage Protection (OVP) become shorter.
The operation of the Bias Assist Function in startup is
as follows. It is necessary to check and adjust the startup
process based on actual operation in the application, so
that poor starting conditions may be avoided.
Figure 9-5 shows the VCC pin voltage behavior during
the startup period.
After the VCC pin voltage increases to VCC(ON) = 15.0
V at startup, the IC starts the operation. Then circuit
current increases and the VCC pin voltage decreases. At
the same time, the auxiliary winding voltage, VD,
increases in proportion to output voltage. These are all
balanced to produce the VCC pin voltage.
9.4
Soft Start Function
Figure 9-6 shows the behavior of VCC pin voltage and
drain current during the startup period.
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 8.75 ms (fixed)
Limited by OCP operation
tLIM < tOLP (min.)
Time
Figure 9-6
VCC and ID behavior during startup
The IC activates the soft start circuitry during the
startup period. Soft start time is fixed to around 8.75 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 a power MOSFET and a
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secondary side rectifier diode.
Since the Leading Edge Blanking Function (refer to
Section 0) is deactivated during the soft start period, there
is the case that ON time is less than the leading edge
blanking time, tBW = 330 ns. After the soft start period,
D/ST pin current, ID, is limited by the Overcurrent
Protection (OCP), until the output voltage increases to the
target operating voltage. This period is given as t LIM. In
case tLIM is longer than the OLP Delay Time, tOLP, the
output power is limited by the Overload Protection (OLP).
Thus, it is necessary to adjust the value of output capacitor
and the turn ratio of auxiliary winding D so that the t LIM is
less than tOLP = 55 ms (min.).
9.5
Constant Output Voltage Control
The IC achieves the constant voltage control of the
power supply output by using the current-mode control
method, which enhances the response speed and provides
the stable operation.
FB/OLP pin voltage is internally added the slope
compensation at the feedback control (refer to Section
4.Functionnal Block Diagram), and the target voltage, VSC,
is generated. The IC compares the voltage, VROCP, of a
current detection resistor with the target voltage, V SC, by
the internal FB comparator, and controls the peak value of
VROCP so that it gets close to VSC, as shown in Figure 9-7
and Figure 9-8.
U1
S/OCP
1
GND
3
FB/OLP
4
PC1
ROCP
VROCP
Figure 9-7
C3
• 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 photo-coupler, 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 I D 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
9-9. This is called the subharmonics phenomenon.
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.
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.
IFB
Target voltage
without Slope Compensation
FB/OLP pin peripheral circuit
Target voltage including
Slope Compensation
-
VSC
+
VROCP
tON1
T
FB Comparator
Voltage on both
sides of ROCP
tON2
T
T
Figure 9-9 Drain current, ID, waveform
in subharmonic oscillation
Drain current,
ID
Figure 9-8
Drain current, ID, and FB comparator
operation in steady operation
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9.6
Leading Edge Blanking Function
The constant voltage control of output of the IC uses the
peak-current-mode control method.
In the peak-current-mode control method, there is a case
that a power MOSFET turns off due to unexpected
response of the FB comparator or Overcurrent Protection
circuit (OCP) to the steep surge current in turning on the
power MOSFET.
In order to prevent this response to the surge voltage in
turning-on the power MOSFET, the Leading Edge
Blanking Time, tBW = 330 ns is built-in. During tBW, the
OCP threshold voltage becomes VOCP(LEB) = 1.69 V in
order not to respond to the turn-on drain current surge
(refer to Section 9.10).
Output current,
IOUT
Below several kHz
Drain current,
ID
Normal
operation
Figure 9-10
9.9
9.7
Random Switching Function
The IC modulates its switching frequency randomly by
superposing the modulating frequency on f OSC(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.
9.8
Automatic Standby Mode Function
Automatic standby mode is activated automatically
when FB/OLP pin voltage decreases to VFB(OFF) = 1.16 V.
The operation mode becomes burst oscillation, as
shown in Figure 9-10. Burst oscillation 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 oscillation mode
becomes just a few kilohertz. Because the IC suppresses
the peak drain current well during burst oscillation mode,
audible noises can be reduced.
If the VCC pin voltage decreases to VCC(BIAS) = 9.6 V
during the transition to the burst oscillation mode, the Bias
Assist Function is activated and stabilizes the Standby
mode operation, because ICC(ST) is 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
winding and/or reducing the value of R2 (refer to Section
10.1).
Burst oscillation
Standby
operation
Normal
operation
Auto Standby mode timing
Brown-In and Brown-Out Function
This function stops switching operation when it detects
low input line voltage, and thus prevents excessive input
current and overheating.
This function turns on and off switching operation
according to BR pin voltage detecting the AC input
voltage. When the BR pin voltage becomes more than
VBR(DIS) = 0.6 V, this function is activated.
Figure 9-11 shows waveforms of the BR pin voltage
and the drain currnet.
Even if the IC is in the operating state that the VCC pin
voltage is VCC(OFF) or more, when the AC input voltage
decreases from steady-state and the BR pin voltage falls to
VBR(OUT) = 4.80 V or less for the OLP Delay Time,
tOLP = 75 ms, the IC stops switching operation.
When the AC input voltage increases and the BR pin
voltage reaches VBR(IN) = 5.60 V or more in the operating
state that VCC pin voltage is VCC(OFF) or more, the IC starts
switching operation.
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) or less.
BR pin voltage
VBR(IN)
VBR(OUT)
Drain current,
ID
Figure 9-11
tOLP
BR pin voltage and drain current
waveforms
There are two types of detection method as follows:
9.9.1 DC Line Detection
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Figure 9-12 shows the BR pin peripheral circuit of DC
line detection. There is a ripple voltage on C1 occurring at
a half period of AC cycle. In order to detect each peak of
the ripple voltage, the time constant of RC and C4 should
be shorter than a half period of AC cycle.
Since the cycle of the ripple voltage is shorter than tOLP,
the switching operation does not stop when only the
bottom part of the ripple voltage becomes lower than
VBR(OUT).
Thus it minimizes the influence of load conditions on
the voltage detection.
The components around the BR pin:
・ RA and RB are a few megohms. Because of high
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 is a few hundred kilohms
・ C4 is 470 pF to 2200 pF for high frequency noise
reduction
BR1
VAC
RA
VDC
U1
C1
RB
2
RC
BR
C4
GND
3
Parameter
VBR(IN)
Value
(Typ.)
5.60 V
VBR(OUT)
4.80 V
Symbol
Brown-In Threshold Voltage
Brown-Out Threshold Voltage
VDC(OP) can be expressed as the effective value of AC
input voltage using Equation (4).
VAC ( OP ) RMS =
1
2
VDC( OP )
(4)
RA, RB, RC and C4 should be selected based on actual
operation in the application.
9.9.2 AC Line Detection
Figure 9-13 shows the BR pin peripheral circuit of AC
line detection. In order to detect the AC input voltage, the
time constant of RC and C4 should be longer than the
period of AC cycle. Thus the response of the BR pin
detection becomes slow compared with the DC line
detection. This method detects the AC input voltage, and
thus it minimizes the influence from load conditions. Also,
this method is free of influence from C1 charging and
discharging time.
BR1
VAC
RA
3
VCC
RS
Figure 9-12
DC line detection
VDC
Neglecting the effect of both input resistance and
forward voltage of rectifier diode, the reference value of
C1 voltage when the Brown-In and Brown-Out Function
is activated is calculated as follows:
R + RB
VDC( OP ) = VBR ( TH) 1 + A
R C
(3)
where,
VDC(OP) : C1 voltage when the Brown-In and BrownOut Function is activated
VBR(TH) : Any one of threshold voltage of the BR pin
(see Table 9-1)
Table 9-1
BR pin threshold voltage
U1
RB
C1
2
RC
Figure 9-13
BR
C4
GND
3
AC line detection
The components around the BR pin:
・ RA and RB are a few megohms. Because of high
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 is a few hundred kilohms
・ RS must be adjusted so that the BR pin voltage is
more than VBR(DIS) = 0.6 V when the VCC pin voltage
is VCC(OFF) = 8.5 V
・ C4 is 0.22 μF to 1 μF for averaging AC input voltage
and high frequency noise reduction
Neglecting the effect of input resistance is zero, the
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reference effective value of AC input voltage when the
Brown-In and Brown-Out Function is activated is
calculated as follows:
VAC ( OP ) RMS
R + RB
=
VBR ( TH) 1 + A
R C
2
C（RC）
Damper snubber
T1
D51
C1
C51
(5
)
where,
VAC(OP)RMS : The effective value of AC input voltage
when the Brown-In and Brown-Out
Function is activated
VBR(TH)
: Any one of threshold voltage of the BR pin
(see Table 9-1)
7, 8
D/ST
U1
ROCP
RA, RB, RC and C4 should be selected based on actual
operation in the application.
Overcurrent Protection (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 OCP threshold voltage.
During the Leading Edge Blanking Time, the OCP
threshold voltage becomes VOCP(LEB) = 1.69 V which is
higher than the normal OCP threshold voltage as shown in
Figure 9-14. Changing to this threshold voltage prevents
the IC from responding to the surge voltage in turning-on
the power MOSFET. This function operates as protection
at the condition such as output windings shorted or
unusual withstand voltage of secondary-side rectifier
diodes.
When the power MOSFET turns on, the surge voltage
width of the S/OCP pin should be less than tBW, as shown
in Figure 9-14. In order to prevent surge voltage, pay extra
attention to ROCP trace layout (refer to Section 10.2).
In addition, if a C (RC) damper snubber of Figure 9-15
is used, reduce the capacitor value of damper snubber.
tBW
VOCP(LEB)
VOCP’
Figure 9-15
Damper snubber
< 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
detection voltage of actual drain peak current is, compared
to VOCP. Thus, the peak current has some variation
depending on the AC input voltage in OCP state. In order
to reduce the variation of peak current in OCP state, the
IC incorporates a built-in Input Compensation Function.
The Input Compensation Function is the function of
correction of the OCP threshold voltage depending with
AC input voltage, as shown in Figure 9-16.
When AC input voltage is low (ON Duty is broad), the
OCP threshold voltage is controlled to become high. The
difference of peak drain current become small compared
with the case where the AC input voltage is high (ON Duty
is narrow).
1.0
OCP Threshold Voltage after
compensation, VOCP'
9.10 Overcurrent Protection (OCP)
C（RC）
Damper snubber
S/OCP
1
VOCP(H)
VOCP(L)
DDPC=36%
0.5
0
50
DMAX=75%
100
ON Duty (%)
Surge pulse voltage width at turning-on
Figure 9-14
Figure 9-16 Relationship between ON Duty and Drain
Current Limit after compensation
S/OCP pin voltage
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The compensation signal depends on ON Duty. The
relation between the ON Duty and the OCP threshold
voltage after compensation VOCP' is expressed as Equation
(6). When ON Duty is broader than 36 %, the VOCP'
becomes a constant value VOCP(H) = 0.888 V
U1
GND
FB/OLP
3 IFB
4
VCC
5
D2 R2
PC1
VOCP ' = VOCP ( L) + DPC ONTime
C3
ONDuty
= VOCP ( L) + DPC
f OSC( AVG )
C2
D
(6)
where,
VOCP(L): OCP Threshold Voltage at Zero ON Duty (V)
DPC: OCP Compensation Coefficient (mV/μs)
ONTime: On-time of a power MOSFET (μs)
ONDuty: On duty of a power MOSFET (%)
fOSC(AVG): Average PWM Switching Frequency (kHz)
Figure 9-17
FB/OLP pin peripheral circuit
Non-switching interval
VCC pin voltage
VCC(ON)
VCC(OFF)
9.11 Overload Protection (OLP)
Figure 9-17 shows the FB/OLP pin peripheral circuit,
and Figure 9-18 shows each waveform for Overload
Protection (OLP) operation.
When the peak drain current of ID is limited by
Overcurrent Protection operation, the output voltage,
VOUT, decreases and the feedback current from the
secondary photo-coupler becomes zero. Thus, the
feedback current, IFB, charges C3 connected to the
FB/OLP pin and FB/OLP pin voltage increases. When the
FB/OLP pin voltage increases to VFB(OLP) = 7.3 V or more
for the OLP delay time, tOLP = 75 ms or more, the OLP is
activated, the IC stops switching operation.
During OLP operation, the Bias Assist Function is
disabled. Thus, VCC pin voltage decreases to VCC(OFF), the
control circuit stops operation. After that, the IC reverts to
the initial state by UVLO circuit, and the IC starts
operation when the VCC pin voltage increases to VCC(ON)
by startup current. Thus, the intermittent operation by
UVLO is repeated in OLP state.
This intermittent operation reduces the stress of parts
such as a power MOSFET and a 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.
FB/OLP pin voltage
tOLP
VFB(OLP)
tOLP
Drain current,
ID
Figure 9-18
OLP operational waveforms
9.12 Overvoltage Protection (OVP)
When the voltage between the VCC pin and the GND
pin increases to VCC(OVP) = 29.1 V or more, Overvoltage
Protection (OVP) is activated and the IC stops switching
operation.
During OVP operation, the Bias Assist Function is
disabled, the intermittent operation by UVLO is repeated
(refer to Section 9.11). When the fault condition is
removed, the IC returns to normal operation automatically
(refer to Figure 9-19). When VCC pin voltage is provided
by using auxiliary winding of transformer, the overvoltage
conditions such as output voltage detection circuit open
can be detected because the VCC pin voltage is
proportional to output voltage. The approximate value of
output voltage VOUT(OVP) in OVP condition is calculated
by using Equation (7).
VOUT(OVP) =
VOUT ( NORMAL )
VCC ( NORMAL )
29.1(V)
(7)
where,
VOUT(NORMAL): Output voltage in normal operation
VCC(NORMAL): VCC pin voltage in normal operation
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10. Design Notes
VCC pin voltage
VCC(OVP)
VCC(ON)
10.1 External Components
VCC(OFF)
Take care to use properly rated, including derating as
necessary and proper type of components.
Drain current,
ID
Figure 9-19
• Input and 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.
OVP operational waveforms
9.13 Thermal Shutdown (TSD)
Figure 9-20 shows the Thermal Shutdown (TSD)
operational waveforms.
When the temperature of control circuit increases to
Tj(TSD) = 145 °C or more, TSD is activated, and the IC
stops switching operation. After that, VCC pin voltage
decreases. When the VCC pin voltage decreases to
VCC(BIAS), the Bias Assist Function is activated and the
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.
• S/OCP Pin Peripheral Circuit
In Figure 10-1, ROCP is the resistor for the current
detection. A high frequency switching current flows to
ROCP, and may cause poor operation if a high inductance
resistor is used. Choose a low inductance and high surgetolerant type.
CRD clamp snubber
BR1
T1
VAC
P
D1
RB
D2
8
D/ST D/ST
R2
5
7
C5
NC
VCC
C2
D
U1
S/OCP BR GND FB/OLP
C（RC）
Damper snubber
1
RC
Junction Temperature,
Tj
R1
C6
RA
C1
Figure 10-1
2
3
4
C4
C3
PC1
ROCP
The IC peripheral circuit
Tj(TSD)
Tj(TSD)−Tj(TSD)HYS
Bias assist
function
ON
ON
OFF
OFF
VCC pin voltage
VCC(ON)
VCC(BIAS)
VCC(OFF)
• BR pin peripheral circuit
Because RA and RB (see Figure 10-1) are applied high
voltage and are high resistance, the following should be
considered according to the requirement of the
application:
▫ Select a resistor designed against electromigration,
or
▫ Use a combination of resistors in series for that to
reduce each applied voltage
Drain current
ID
See Section 9.9 about the AC input voltage detection
function and the components around the BR pin.
Figure 9-20
TSD operational waveforms
• FB/OLP Pin Peripheral Circuit
C3 (see Figure 10-1) is for high frequency noise
rejection and phase compensation, and should be
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connected close to the FB/OLP pin and the GND pin. The
value of C3 is recommended to be about 2200 pF to 0.01
µF, and should be selected based on actual operation in
the application.
• VCC Pin Peripheral Circuit
The value of C2 is generally recommended to be 10 µF
to 47 μF (refer to Section 9.1 Startup Operation,
because the startup time is determined by the value of
C2).
In actual power supply circuits, there are cases in which
VCC pin voltage fluctuates in proportion to the output
current, IOUT (see Figure 10-2), and the Overvoltage
Protection (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
winding when a power MOSFET turns off.
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 10-1). 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.
VCC pin voltage
Without R2
With R2
be selected based on actual operation in the application.
L51
T1
VOUT
(+)
D51
PC1
R55
C51
S
R54
R51
R52
C53
C52 R53
U51
R56
(-)
Figure 10-3
Peripheral circuit around secondary shunt
regulator (U51)
• 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/mm 2.
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.
Output current, IOUT
Figure 10-2
Variation of VCC pin voltage and power
• Snubber Circuit
If the surge voltage of VDS is large, the circuit should be
added as follows (see Figure 10-1);
・ A clamp snubber circuit of a capacitor-resistor- diode
(CRD) combination should be added on the primary
winding P.
・ 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/GND pin.
When the damper snubber circuit is added, this
components should be connected near the D/ST pin
and the S/OCP pin.
• Phase Compensation
A typical phase compensation circuit with a secondary
shunt regulator (U51) is shown in Figure 10-3.
C52 and R53 are for phase compensation. The value of
C52 and R53 are recommended to be around 0.047μF to
0.47μF and 4.7 kΩ to 470 kΩ, respectively. They should
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 (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
STR-A6000MZ/HZ-DSE Rev.1.4
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STR-A6000MZ/HZ Series
outputs.
Figure 10-4 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. This
structure reduces the surge of D, and improves the
line-regulation of outputs.
Bobbin
Margin tape
P1 S1 P2 S2 D
Margin tape
Winding structural example (a)
and thus it should be as wide trace and small loop as
possible.
If C1 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 the IC may be affected from the
large current of the main trace that flows in control
ground trace, the control ground trace should be
separated from main trace and connected at a single
point grounding of the point A in Figure 10-5 as close
to the ROCP 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 C2 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 GND pin is recommended.
(4) 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 10-5) which is
close to the base of ROCP.
Bobbin
Margin tape
P1 S1 D S2 S1 P2
Margin tape
(5) Peripheral components of the IC
The components for control connected to the IC
should be placed as close as possible to the IC, and
should be connected as short as possible to the each
pin.
Winding structural example (b)
Figure 10-4
Winding structural examples
10.2 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 10-5 shows the circuit design example.
(1) Main Circuit Trace Layout
This is the main trace containing switching currents,
(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 a 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.
(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 D/ST pin
trace act as a heatsink, its traces should be as wide as
possible.
STR-A6000MZ/HZ-DSE Rev.1.4
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STR-A6000MZ/HZ Series
(6) Main trace of secondary
side should be wide trace
and small loop
(1) Main trace should be wide
trace and small loop
D51
T1
R1
C6
RA
C1
P
(7)Trace of D/ST pin should beDST
wide for heat release
C51
D1
RB
S
D2
8
D/ST D/ST
C5
R2
5
7
NC
C2
VCC
D
U1
STR-A6000×Z
(3) Loop of the power
supply should be small
S/OCP BR GND FB/OLP
1
2
3
4
ROCP
C3
C4 RC
PC1
(5)The components connected to
the IC should be as close to the
IC as possible, and should be
connected as short as possible
CY
A
(4)ROCP should be as close to S/OCP
pin as possible.
(2) Control GND trace should be connected at a
single point as close to the ROCP as possible
Figure 10-5
Peripheral circuit example around the IC
STR-A6000MZ/HZ-DSE Rev.1.4
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Jan. 13, 2022
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STR-A6000MZ/HZ Series
11. Pattern Layout Example
The following show the PCB pattern layout example and the schematic of circuit using STR-A6000MZ/HZ series.
The PCB pattern layout example is made usable to other ICs in common. The parts in Figure 11-2 are only used.
Figure 11-1
PCB circuit trace layout example
T1
L52
D52
CN51
1
OUT2(+)
2
OUT2(-)
3
OUT1(+)
4
OUT1(-)
R59
C57
R58
C55
R61
C56
R60
CN1
1
F1
L1
JW51
JW52
JW54
JW6
C1
D1
C12
C2
D4
C13
L51
L2
D2 TH1
D51
D3
C3
C4
P1
C5
3
R51
C54
R1
R55
R52
PC1
R2
S1
R54
C51
C53
D7
C52
U51
JW2
R57
R53
R56
R7
D2
JW10
R6
U1
8
7
D/ST
D/ST
5
NC
JW4
D8
R3
JW31
D1
C9
C8
STR-A6000×Z
C31
C32
BR
1
2
GND FB/OLP
C11
3
JW3
JW8
JW7
C6
C7
Figure 11-2
2
OUT4(-)
JW21
U21
D21
1 IN
R4
OUT4(+)
JW53
4
JW11
R5
1
R31
C10
S/OCP
CN31
D31
VCC
CP1
JW9
C21
CN21
3
OUT
GND
2
C22
1
OUT3(+)
2
OUT3(-)
R21
Circuit schematic for PCB circuit trace layout
STR-A6000MZ/HZ-DSE Rev.1.4
SANKEN ELECTRIC CO., LTD.
Jan. 13, 2022
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STR-A6000MZ/HZ Series
12. 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.
⚫ Circuit schematic
IC
STR-A6069HZ
Input voltage
AC85V to AC265V
Maximum output power
7.5 W
Output voltage
5V
Output current
1.5 A (max.)
⚫ Circuit schematic
1
F1
L1
D1
D2
D4
D3
L2
TH1
L51
T1
D51
3
C1
3
C4
R1
C3
R51
C55
R4
S1
C2
R55
R52
C53
PC1
D5
5V/1.5A
R54
R57
C51
P1
R53
C52
S2
U51
5
8
7
D/ST
D/ST
D6
R2
R56
4
R8
NC
VCC
C5
U1
C8
D
STR-A6000×Z
R9
S/OCP
BR
1
2
GND FB/OLP
3
4
PC1
R7
R3
C7
C6
C9
TC_STR-A6000xZ_3_R3
STR-A6000MZ/HZ-DSE Rev.1.4
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STR-A6000MZ/HZ Series
⚫ Bill of materials
Symbol
F1
Part type
Ratings(1)
Recommended
Sanken Parts
Symbol
Fuse
AC250V, 3A
R4
(3)
Ratings(1)
Part type
Metal oxide
330kΩ, 1W
General
330kΩ
L1
(2)
CM inductor
3.3mH
R7
L2
(2)
Inductor
470μH
R8
(3)
General
2.2MΩ
TH1
(2)
R9
(3)
General
2.2MΩ
NTC thermistor
Short
D1
General
600V, 1A
EM01A
PC1
Photo-coupler
PC123 or equiv
D2
General
600V, 1A
EM01A
U1
IC
－
D3
General
600V, 1A
EM01A
T1
Transformer
See the
specification
D4
General
600V, 1A
EM01A
L51
Inductor
5μH
D5
Fast recovery
1000V, 0.5A
EG01C
D51
Schottky
90V, 4A
D6
Fast recovery
200V, 1A
AL01Z
C51
Electrolytic
680μF, 10V
Film, X2
0.047μF, 275V
C52
Ceramic
0.1μF, 50V
C2
Electrolytic
10μF, 400V
C53
Electrolytic
330µF, 10V
C3
Electrolytic
10μF, 400V
C55
Ceramic
1000pF, 1kV
C4
Ceramic
1000pF, 630V
R51
General
220Ω
C5
Electrolytic
22μF, 50V
R52
General
1.5kΩ
General
22kΩ
C1
(2)
(2)
(2)
C6
(2)
Ceramic
0.01μF
R53
C7
(2)
Ceramic
1000pF
R54
General, 1%
Short
C8
(2)
Ceramic
Open
R55
General, 1%
10kΩ
C9
(2)
Ceramic, Y1
2200pF, 250V
R56
General, 1%
10kΩ
R1
(2)
General
Open
R57
General
Open
R2
(2)
General
4.7Ω
U51
Shunt
regulator
VREF=2.5V
TL431 or
equiv
General
1.5Ω, 1/2W
R3
Recommended
Sanken Parts
STRA6069HZ
FMB-G19L
(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.
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.
(2)
STR-A6000MZ/HZ-DSE Rev.1.4
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STR-A6000MZ/HZ Series
⚫ Transformer specification
▫ Primary inductance, LP
▫ Core size
▫ Al-value
▫ Winding specification
：704 μH
：EI-16
：132 nH/N2 (Center gap of about 0.26 mm)
Symbol
Number of
turns (T)
Primary winding
P1
73
2UEW-φ0.18
Auxiliary winding
D
17
2UEW-φ0.18×2
Output winding
S1
6
TEX-φ0.3×2
Output winding
S2
6
TEX-φ0.3×2
Winding
Wire diameter(mm)
VDC
D
S2
S1
S1
P1
Bobbin
GND
VOUT
(-)
D
Cross-section view
Two-layer,
solenoid winding
Single-layer,
solenoid winding
Single-layer,
solenoid winding
Single-layer,
solenoid winding
(+) 5V
P1
D/ST
VCC
Construction
S2
●: Start at this pin
STR-A6000MZ/HZ-DSE Rev.1.4
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STR-A6000MZ/HZ Series
Important Notes
● All data, illustrations, graphs, tables and any other information included in this document (the “Information”) as to Sanken’s
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