STR-A6000_15_技术文档

Off-Line PWM Controllers with Integrated Power MOSFET

STR-A6000 Series

General Descriptions

Package

The STR-A6000 series are power ICs for switching

power supplies, incorporating a MOSFET and a current

mode PWM controller IC.

DIP8

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

cost-performance power supply systems with few

external components.

Not to Scale

Lineup

 Electrical Characteristics

Features

 Current Mode Type PWM Control

 Brown-In and Brown-Out function

 Auto Standby Function

No Load Power Consumption < 25mW

 Operation Mode

Normal Operation -----------------------------PWM Mode

Standby---------------------------- Burst Oscillation Mode

V_DSS(min.)

f_OSC(AVG)

Products

STR-A605×M

STR-A607×M

STR-A605×H

STR-A606×H

STR-A606×HD

650 V

800 V

650 V

700 V

67 kHz

100 kHz

 Random Switching Function

 Slope Compensation Function

 Leading Edge Blanking Function

 Bias Assist Function

 Audible Noise Suppression function during Standby

mode

*STR-A60××HD has two types OCP

 MOSFET ON Resistance and Output Power, P_OUT

*

P_OUT

(Open frame)

P_OUT

(Adapter)

R_DS(ON)

(max.)

Products

AC85

~265V

AC230V

~265V

 Protections

f_OSC(AVG)= 67 kHz

STR-A6051M 3.95 Ω 18.5 W 14 W 31 W 21 W

・Overcurrent Protection (OCP)*; Pulse-by-Pulse,

built-in compensation circuit to minimize OCP point

variation on AC input voltage

STR-A6052M

STR-A6053M

2.8 Ω 22 W 17.5W 35 W 24.5 W

1.9 Ω 26 W 21W 40 W 28 W

6 W 13 W 9 W

・Overload Protection (OLP); auto-restart

・Overvoltage Protection (OVP); latched shutdown

・Thermal Shutdown Protection (TSD); latched shutdown

STR-A6079M 19.2 Ω

8 W

f_OSC(AVG)= 100 kHz

*STR-A60××HD has two types OCP

STR-A6059H

STR-A6069H

STR-A6069HD

STR-A6061H

STR-A6061HD

STR-A6062H

STR-A6062HD

6Ω 17 W 11 W 30 W 19.5 W

Typical Application Circuit

L51

BR1

D51

VOUT

(+)

T1

3.95Ω 20 W 15 W 35 W 23.5 W

2.8 Ω 23 W 18 W 38 W 26.5 W

VAC

R54

R51

R1

C6

PC1

R52

C1

P

R55

C51

D1

S

C53

C52 R53

D2 R2

STR-A6063HD 2.3 Ω 25 W 20 W 40 W 28 W

U51

5

8

7

R56

D/ST D/ST NC VCC

* 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.

D

R_A

R_B

C2

(-)

C5

U1

STR-A6000

S/OCP BR

FB/OLP

4

GND

3

1

2

PC1

C4

C3

R_C

R_OCP

Applications

C_Y

TC_STR-A6000_1_R1

 Low power AC/DC adapter

 White goods

 Auxiliary power supply

 OA, AV and industrial equipment

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

http://www.sanken-ele.co.jp/en/

1

STR-A6000 Series

CONTENTS

General Descriptions----------------------------------------------------------------------- 1

1. Absolute Maximum Ratings--------------------------------------------------------- 3

2. Electrical Characteristics ------------------------------------------------------------ 4

3. Performance Curves ------------------------------------------------------------------ 6

3.1

3.2

3.3

3.4

Derating Curves--------------------------------------------------------------- 6

Ambient Temperature versus Power Dissipation Curve------------- 6

MOSFET Safe Operating Area Curves---------------------------------- 7

Transient Thermal Resistance Curves ----------------------------------- 9

4. Functional Block Diagram----------------------------------------------------------11

5. Pin Configuration Definitions------------------------------------------------------11

6. Typical Application Circuit --------------------------------------------------------12

7. Package Outline-----------------------------------------------------------------------13

8. Marking Diagram --------------------------------------------------------------------13

9. Operational Description-------------------------------------------------------------14

9.1

9.2

9.3

9.4

9.5

9.6

9.7

9.8

9.9

Startup Operation -----------------------------------------------------------14

Undervoltage Lockout (UVLO)-------------------------------------------15

Bias Assist Function---------------------------------------------------------15

Constant Output Voltage Control----------------------------------------15

Leading Edge Blanking Function ----------------------------------------16

Random Switching Function ----------------------------------------------16

Automatic Standby Mode Function--------------------------------------16

Brown-In and Brown-Out Function -------------------------------------17

Overcurrent Protection Function (OCP) -------------------------------19

9.10 Overload Protection Function (OLP) -----------------------------------20

9.11 Overvoltage Protection (OVP) --------------------------------------------20

9.12 Thermal Shutdown Function (TSD) -------------------------------------20

10. Design Notes ---------------------------------------------------------------------------21

10.1 External Components-------------------------------------------------------21

10.2 PCB Trace Layout and Component Placement -----------------------22

11. Pattern Layout Example ------------------------------------------------------------24

12. Reference Design of Power Supply -----------------------------------------------25

OPERATING PRECAUTIONS --------------------------------------------------------27

IMPORTANT NOTES -------------------------------------------------------------------28

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

2

STR-A6000 Series

1. Absolute Maximum Ratings

 The polarity value for current specifies a sink as "+," and a source as "−," referencing the IC.

 Unless otherwise specified T_A= 25 °C, 7 pin = 8 pin

Parameter

Symbol

Test Conditions

Pins

Rating

Units

Notes

A6079M

1.2

A6059H / 69H

/ 69HD

A6051M / 61H

/ 61HD

A6052M / 62H

/ 62HD

1.8

2.5

3.0

Drain Peak Current⁽¹⁾

I_DPEAK

Single pulse

8 – 1

A

A6053M / 63HD

A6079M

4.0

7

I_LPEAK=1.2A

I_LPEAK=1.8A

A6059H / 69H

/ 69HD

24

I_LPEAK=2A

A6061H / 61HD

A6051M

46

47

I_LPEAK=2A

Avalanche Energy⁽²⁾⁽³⁾

E_AS

8 – 1

mJ

I_LPEAK=2.2A

I_LPEAK=2.3A

I_LPEAK=2.5A

I_LPEAK=2.7A

A6062H / 62HD

A6052M

56

62

A6063HD

72

A6053M

86

S/OCP Pin Voltage

BR Pin Voltage

V_S/OCP

V_BR

I_BR

1 − 3

2 − 3

4 − 3

5 − 3

− 2 to 6

− 0.3 to 7

1.0

V

BR Pin Sink Current

FB/OLP Pin Voltage

FB/OLP Pin Sink Current

VCC Pin Voltage

mA

V

V_FB

I_FB

− 0.3 to 14

1.0

mA

V

V_CC

32

MOSFET Power

(5)

P_D1

P_D2

T_OP

8 – 1

5 – 3

−

1.35

1.2

W

°C

Dissipation⁽⁴⁾

Control Part Power

Dissipation

Operating Ambient

− 20 to 125

Temperature⁽⁶⁾

Storage Temperature

Channel Temperature

T_stg

T_ch

−

− 40 to 125

°C

150

⁽¹⁾Refer to 3.3 MOSFET Safe Operating Area Curves

⁽²⁾Refer to Figure 3-2 Avalanche Energy Derating Coefficient Curve

⁽³⁾Single pulse, V_DD= 99 V, L = 20 mH

⁽⁴⁾Refer to Figure 3-3 Ambient temperature versus power dissipation curve

⁽⁵⁾When embedding this hybrid IC onto the printed circuit board (cupper area in a 15 mm × 15 mm)

⁽⁶⁾The recommended internal frame temperature, T_F, is 115°C (max.)

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

3

STR-A6000 Series

2. Electrical Characteristics

 The polarity value for current specifies a sink as "+," and a source as "−," referencing the IC.

 Unless otherwise specified, T_A= 25 °C, V_CC= 18 V, 7 pin = 8 pin

Test

Conditions

Parameter

Symbol

Pins

Min.

Typ.

Max.

Units

Notes

Power Supply Startup Operation

Operation Start Voltage

Operation Stop Voltage⁽¹⁾

Circuit Current in Operation

V_CC(ON)

V_CC(OFF)

I_CC(ON)

5 − 3

13.8

7.3

−

15.3

8.1

−

16.8

8.9

V

V_CC= 12 V

2.5

mA

Startup Circuit Operation

Voltage

V_ST(ON)

I_STARTUP

V_CC(BIAS)

8 − 3

5 − 3

−

38

− 2.5

9.5

−

V

mA

V

V_CC= 13.5 V

Startup Current

− 3.7

8.5

− 1.5

10.5

Startup Current Biasing

Threshold Voltage

I_CC

= − 100 µA

Normal Operation

A60××M

60

90

−

67

100

5

74

110

−

Average Switching

Frequency

f_OSC(AVG)

8 − 3

kHz

A60××H / HD

A60××M

Switching Frequency

Modulation Deviation

Δf

8 − 3

A60××H / HD

−

8

−

Maximum ON Duty

D_MAX

t_ON(MIN)

77

−

83

89

−

%

ns

A60××M

540

470

Minimum ON Time

A60××H / HD

−

Protection Function

Leading Edge Blanking Time

A60××M

−

340

280

20

−

t_BW

−

ns

A60××H / HD

A60××M

OCP Compensation

Coefficient

DPC

mV/μs

A60××H / HD

33

OCP Compensation ON Duty

D_DPC

−

36

%

V

OCP Threshold Voltage at

Zero ON Duty

OCP Threshold Voltage at

36% ON Duty

OCP Threshold Voltage in

Leading Edge Blanking Time

V_OCP(L)

1 − 3

0.70

0.81

1.32

0.78

0.9

0.86

0.99

1.78

V_CC= 32 V

V_CC= 12 V

V_OCP(H)

1 − 3

V

A60××HD

V_OCP(LEB)

1.55

Maximum Feedback Current

Minimum Feedback Current

I_FB(MAX)

I_FB(MIN)

4 − 3 − 340 − 230 − 150

µA

4 − 3

− 30

− 15

− 7

FB/OLP pin Oscillation Stop

Threshold Voltage

V_FB(STB)

0.85

0.95

1.05

V

OLP Threshold Voltage

OLP Operation Current

OLP Delay Time

V_FB(OLP)

I_CC(OLP)

t_OLP

4 − 3

5 − 3

−

7.3

−

8.1

300

68

8.9

600

82

V

µA

ms

V

V_CC= 12 V

54

11

FB/OLP Pin Clamp Voltage

V_FB(CLAMP)

4 − 3

12.8

14

(1)

V

> V_CC(OFF)always.

CC(BIAS)

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

4

STR-A6000 Series

Test

Conditions

Parameter

Symbol

V_BR(IN)

Pins

2 − 3

5 − 3

Min.

5.2

4.45

6

Typ.

5.6

Max.

6

Units

V

Notes

V_CC= 32 V

Brown-In Threshold Voltage

Brown-Out Threshold

Voltage

V_BR(OUT)

V_BR(CLAMP)

V_BR(DIS)

4.8

5.15

7

V

BR Pin Clamp Voltage

6.4

V

BR Function Disabling

Threshold

0.3

26

0.48

29

0.7

32

−

V

OVP Threshold Voltage

V_CC(OVP)

I_CC(LATCH)

V

Latch Circuits Holding

V_CC= 9.5 V

−

700

μA

Current⁽²⁾

Thermal Shutdown Operating

Temperature

T_j(TSD)

−

135

−

°C

MOSFET

A605×

650

700

800

−

Drain-to-Source Breakdown

Voltage

V_DSS

8 – 1

V

A606×

−

A607×

Drain Leakage Current

I_DSS

300

19.2

μA

A6079M

−

A6059H / 69H

/ 69HD

A6051M / 61H

/ 61HD

A6052M / 62H

/ 62HD

−

6

3.95

2.8

I_DS= 0.4A

On Resistance

R_DS(ON)

8 − 1

Ω

A6063HD

A6053M

−

2.3

1.9

250

400

ns

Switching Time

t_f

8 – 1

A6053M

Thermal Resistance

Channel to Case Thermal

Resistance⁽³⁾

θ_ch-C

−

22

°C/W

⁽²⁾A latch circuit is a circuit operated with Overvoltage Protection function (OVP) and/or Thermal Shutdown function

(TSD) in operation.

(3)

θ

is thermal resistance between channel and case. Case temperature (T_C) is measured at the center of the case top

ch-C

surface.

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

5

STR-A6000 Series

3. Performance Curves

3.1 Derating Curves

100

80

60

40

20

0

80

60

40

20

0

25

50

75

100

125

150

0

25

50

75

100 125 150

Channel Temperature, Tch (°C)

Figure 3-1 SOA Temperature Derating Coefficient Curve

Figure 3-2 Avalanche Energy Derating Coefficient Curve

3.2 Ambient Temperature versus Power Dissipation Curve

1.6

1.4

1.35W

1.2

1

0.8

0.6

0.4

0.2

0

20 40 60 80 100 120 140 160

Ambient Temperature, T_A(°C )

Figure 3-3 Ambient temperature versus

power dissipation curve

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

6

STR-A6000 Series

3.3 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, T_A= 25 °C, Single pulse

 STR-A6051M

 STR-A6052M

10

0.1ms

1

1ms

0.1

0.01

1

0.01

1

10

100

1000

10

100

1000

Drain-to-Source Voltage (V)

 STR-A6053M

 STR-A6079M

10

0.1ms

1

1ms

0.1

0.01

1

10

100

1000

1

10

100

1000

Drain-to-Source Voltage (V)

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

7

STR-A6000 Series

 STR-A6059H

 STR-A6061H / 61HD

10

0.1ms

1

0.1

1ms

0.1

0.01

1

0.01

10

100

1000

1

10

100

1000

Drain-to-Source Voltage (V)

 STR-A6062H / 62HD

 STR-A6063HD

10

0.1ms

1

1ms

0.1

0.01

1

10

100

1000

Drain-to-Source Voltage (V)

 STR-A6069H / 69HD

10

0.1ms

1

0.1

1ms

0.01

1

10

100

1000

Drain-to-Source Voltage (V)

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

8

STR-A6000 Series

3.4 Transient Thermal Resistance Curves

 STR-A6051M / 61H / 61HD

10

1

0.1

0.01

1µ

10µ

100µ

1m

10m

100m

Time (s)

 STR-A6052M / 62H / 62HD

10

1

0.1

0.01

1µ

10µ

100µ

1m

10m

100m

Time (s)

 STR-A6053M

10

1

0.1

0.01

1µ

10µ

100µ

1m

10m

100m

Time (s)

 STR-A6059M / 69H / 69HD

10

1

0.1

0.01

1µ

10µ

100µ

1m

10m

100m

Time (s)

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

9

STR-A6000 Series

 STR-A6079M

10

1

0.1

0.01

100n

1µ

10µ

100µ

1m

10m

100m

Time (s)

 STR-A6063HD

10

1

0.1

0.01

0.001

1µ

10µ

100µ

1m

10m

100m

Time (s)

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

10

STR-A6000 Series

4. Functional Block Diagram

VCC

5

D/ST

7,8

Startup

UVLO

REG

VREG

OVP

TSD

BR

2

Brown-in

Brown-out

6.4V

DRV

PWM OSC

S

Q

R

OCP

7V

VCC

Drain peak current

compensation

OLP

S/OCP

1

Feedback

control

FB/OLP

4

LEB

12.8V

GND

3

Slope

compensation

BD_STR-A6000_R1

5. Pin Configuration Definitions

1

Name

Descriptions

MOSFET source and overcurrent protection

(OCP) signal input

S/GND

D/ST

1

2

3

4

S/OCP

8

7

6

2

3

BR

Brown-In and Brown-Out detection voltage input

Ground

BR

GND

Constant voltage control signal input and over

load protection (OLP) signal input

Power supply voltage input for control part and

overvoltage protection (OVP) signal input

4

5

FB /OLP

FB/OLP

VCC

5

VCC

6

7

8

−

(Pin removed)

D/ST

MOSFET drain and startup current input

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

11

STR-A6000 Series

6. Typical Application Circuit

 The following drawings show circuits enabled and disabled the Brown-In/Brown-Out function.

 The PCB traces D/ST pins should be as wide as possible, in order to enhance thermal dissipation.

 In applications having a power supply specified such that 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

L51

BR1

C1

D51

VOUT

(+)

T1

VAC

R54

R51

R1

C6

R_A

R_B

PC1

R52

P

R55

C51

D1

S

C53

C52 R53

D2 R2

U51

5

8

7

R56

D/ST D/ST NC VCC

D

C2

(-)

C5

U1

STR-A6000

S/OCP BR

FB/OLP

4

GND

3

C（RC）

damper snubber

1

2

PC1

C4

C3

R_C

R_OCP

C_Y

TC_STR-A6000_2_R1

Figure 6-1 Typical application circuit (enabled Brown-In/Brown-Out function, DC line detection)

CRD clamp snubber

L51

BR1

C1

D51

VOUT

(+)

T1

VAC

R54

R51

R1

C6

PC1

R52

P

R55

C51

D1

S

C53

C52 R53

D2 R2

U51

5

8

7

R56

D/ST D/ST NC VCC

D

(-)

C2

C5

U1

STR-A6000

S/OCP BR

FB/OLP

4

GND

3

C（RC）

damper snubber

1

2

PC1

C3

C_Y

R_OCP

TC_STR-A6000_3_R1

Figure 6-2 Typical application circuit (disabled Brown-In/Brown-Out function)

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

12

STR-A6000 Series

7. Package Outline

 DIP8

 The following show a representative type of DIP8.

NOTES:

1) Dimension is in millimeters

2) Pb-free. Device composition compliant with the RoHS directive

8. Marking Diagram

STR-A60××M

STR-A60××H

8

STR-A60××HD

8

A 6 0 × × H

A 6 0 × × ×

Part Number

S K Y M D D

S K Y M D

Lot Number

Y is the Last digit of the year (0 to 9)

1

Y is the Last digit of the year (0 to 9)

M is the Month (1 to 9, O, N or D)

D is a period of days:

1 : 1^stto 10^th

1

M is the Month (1 to 9, O, N or D)

D is a period of days:

1 : 1^stto 10^th

2 : 11^thto 20^th

3 : 21^stto 31^st

2 : 11^thto 20^th

3 : 21^stto 31^st

Sanken Control Number

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

13

STR-A6000 Series

 With Brown-In / Brown-Out function

9. Operational Description

When BR pin voltage is more than V_BR(DIS)= 0.48 V

and less than V_BR(IN)= 5.6 V, the Bias Assist Function

(refer to Section 9.3) is disabled. Thus, VCC pin

voltage repeats increasing to V_CC(ON)and decreasing to

V_CC(OFF)(shown in Figure 9-3). When BR pin voltage

becomes V_BR(IN)or more, the IC starts switching

operation.

 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).

BR1

T1

9.1 Startup Operation

VAC

Figure 9-1 shows the circuit around IC. Figure 9-2

shows the start up operation.

C1

P

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_ST(ON)= 38 V, the

startup circuit starts operation.

During the startup process, the constant current,

I_STARTUP= − 2.5 mA, charges C2 at VCC pin. When

VCC pin voltage increases to V_CC(ON)= 15.3 V, the

control circuit starts operation.

7, 8

D/ST

D2 R2

5

3

U1

VCC

D

C2

V_D

GND

BR

2

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.

Figure 9-1 VCC pin peripheral circuit

(Without Brown-In / Brown-Out)

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.

VCC pin

voltage

V_CC(ON)

t_START

V_CC(BIAS)(max.) V_CCV_{CC(OVP )}(min.)

Drain current,

I_D

 V_CC



26 (V)

⇒10.5 (V)

(1)

The oscillation start timing of IC depends on

Brown-In / Brown-Out function (refer to Section 9.8).

Figure 9-2 Startup operation

(Without Brown-In / Brown-Out)

 Without Brown-In / Brown-Out function (BR pin

voltage is V_BR(DIS)= 0.48 V or less)

When VCC pin voltage increases to V_CC(ON), the IC

starts switching operation, As shown in Figure 9-2.

VCC pin

voltage

t_START

V_CC(ON)

V_CC(OFF)

The startup time of IC is determined by C2 capacitor

value. The approximate startup time t_START(shown in

Figure 9-2) is calculated as follows:

BR pin

voltage

V_BR(IN)

V

_{CC(ON )}－V_CC(INT)

t_START C2 ×

(2)

I_STRATUP

Drain current,

I_D

where,

t_START: Startup time of IC (s)

V_CC(INT): Initial voltage on VCC pin (V)

Figure 9-3 Startup operation

(With Brown-In / Brown-Out)

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pin voltage decreases to the startup current threshold

biasing voltage, V_CC(BIAS)= 9.5 V. While the Bias Assist

function is activated, any decrease of the VCC pin

voltage is counteracted by providing the startup current,

I_STARTUP, from the startup circuit. Thus, the VCC pin

voltage is kept almost constant.

By the Bias Assist function, the value of C2 is

allowed to be small and the startup time becomes shorter.

Also, because the increase of VCC pin voltage becomes

faster when the output runs with excess voltage, the

response time of the OVP function becomes shorter.

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.

9.2 Undervoltage Lockout (UVLO)

Figure 9-4 shows the relationship of VCC pin voltage

and circuit current I_CC. When VCC pin voltage decreases

to V_CC(OFF)= 8.1 V, the control circuit stops operation by

UVLO (Undervoltage Lockout) circuit, and reverts to

the state before startup.

Circuit current, I_CC

I_CC（ON）

Stop

Start

9.4 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.

The FB/OLP pin voltage is internally added the slope

compensation at the feedback control (refer to Section 4

Functional Block Diagram), and the target voltage, V_SC,

is generated. The IC compares the voltage, V_ROCP, of a

current detection resistor with the target voltage, V_SC, by

the internal FB comparator, and controls the peak value

of V_ROCPso that it gets close to V_SC, as shown in Figure

9-6 and Figure 9-7.

VCC pin

voltage

V_CC（OFF）

V_CC（ON）

Figure 9-4 Relationship between

VCC pin voltage and I_CC

9.3 Bias Assist Function

Figure 9-5 shows VCC pin voltage behavior during

the startup period.

After VCC pin voltage increases to V_CC(ON)= 15.3 V

at startup, the IC starts the operation. Then circuit

current increases and VCC pin voltage decreases. At the

same time, the auxiliary winding voltage V_Dincreases in

proportion to output voltage. These are all balanced to

produce VCC pin voltage.

U1

S/OCP

1

GND FB/OLP

3

4

VCC pin

voltage

Startup success

Target operating

voltage

Increase with rising of

output voltage

PC1

IC starts operation

V_ROCP

R_OCP

I_FB

C3

V_CC(ON)

V_CC(BIAS)

Figure 9-6 FB/OLP pin peripheral circuit

Bias assist period

V_CC(OFF)

Target voltage including

Slope Compensation

Startup failure

Time

V_SC

-

Figure 9-5 VCC pin voltage during startup period

+

V_ROCP

Voltage on both

sides of R_OCP

FB Comparator

The surge voltage is induced at output winding at

turning off a power MOSFET. When the output load is

light at startup, the surge voltage causes the unexpected

feedback control. This results the lowering of the output

power and VCC pin voltage. When the VCC pin voltage

decreases to V_CC(OFF)= 8.1 V, the IC stops switching

operation and a startup failure occurs. In order to prevent

this, the Bias Assist function is activated when the VCC

Drain current,

I_D

Figure 9-7 Drain current, I_D, and FB comparator

operation in steady operation

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 Light load conditions

9.5 Leading Edge Blanking Function

When load conditions become lighter, the output

voltage, V_OUT, 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, V_SCdecreases,

and the peak value of V_ROCPis controlled to be low,

and the peak drain current of I_Ddecreases.

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 response to the surge voltage

in turning-on the power MOSFET, the Leading Edge

Blanking, t_BW(STR-A60××H for 340 ns, STR-A60××H

This control prevents the output voltage from

increasing.

and STR-A60××HD for 280 ns) is built-in. During t_BW

,

 Heavy load conditions

the OCP threshold voltage becomes about 1.7 V which

is higher than the normal OCP threshold voltage (refer

to Section 9.9).

When load conditions become greater, the IC

performs the inverse operation to that described above.

Thus, V_SCincreases and the peak drain current of I_D

increases.

This control prevents the output voltage from

decreasing.

9.6 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.

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

9-8. 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 V_SC, the

subharmonics phenomenon is suppressed.

9.7 Automatic Standby Mode Function

Automatic standby mode is activated automatically

when the drain current, I_D, reduces under light load

conditions, at which I_Dis less than 15 % to 20 % of the

maximum drain current (it is in the OCP state). The

operation mode becomes burst oscillation, as shown in

Figure 9-9. Burst oscillation mode reduces switching

losses and improves power supply efficiency because of

periodic non-switching intervals.

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.

Output current,

Burst oscillation

I_OUT

Target voltage

without Slope Compensation

Below several kHz

Drain current,

I_D

Normal

Standby

Normal

operation

t_ON1

t_ON2

T

Figure 9-9 Auto Standby mode timing

Figure 9-8 Drain current, I_D, waveform

in subharmonic oscillation

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 V_CC(BIAS)= 9.5 V

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during the transition to the burst oscillation mode, the

Bias Assist function is activated and stabilizes the

Standby mode operation, because I_STARTUPis provided to

the VCC pin so that the VCC pin voltage does not

operation period becomes t_OLP= 68 ms or more, the

IC stops switching operation.

 STR-A60××HD:

When the BR pin voltage falls to V_BR(OUT)= 4.8 V

or less for t_OLP= 68 ms, the IC stops switching

operation.

decrease to V_CC(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 V_CC(BIAS), for

example, by adjusting the turns ratio of the auxiliary

winding and secondary winding and/or reducing the

value of R2 in Figure 10-2 (refer to Section 10.1

Peripheral Components for a detail of R2).

There are two types of detection method as follows:

9.8.1 DC Line Detection

Figure 9-11 shows 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 R_Cand C4 should be shorter than a half

period of AC cycle.

Since the cycle of the ripple voltage is shorter than

t_OLP, the switching operation does not stop when only

the bottom part of the ripple voltage becomes lower

9.8 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 the BR pin voltage detecting the AC input

voltage. When BR pin voltage becomes more than

V_BR(DIS)= 0.48 V, this function is activated.

than V_BR(OUT)

.

Thus it minimizes the influence of load conditions

on the voltage detection.

Figure 9-10 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 V_CC(OFF)or more, when the AC input

voltage decreases from steady-state and the BR pin

voltage falls to V_BR(OUT)= 4.8 V or less for the OLP

Delay Time, t_OLP= 68 ms, the IC stops switching

operation. When the AC input voltage increases and the

BR pin voltage reaches V_BR(IN)= 5.6 V or more in the

operating state that the VCC pin voltage is V_CC(OFF)or

more, the IC starts switching operation.

BR1

V_AC

R_A

C1

U1

V_DC

R_B

2

BR

GND

3

R_C

C4

In case 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 V_BR(DIS)or less.

Figure 9-11 DC line detection

The components around BR pin:

BR pin voltage

V_BR(IN)

V_BR(OUT)

・ R_Aand R_Bare 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.

t_OLP

Drain current,

I_D

Figure 9-10 BR pin voltage and drain current waveforms

・ R_Cis a few hundred kilohms

・ C4 is 470 pF to 2200 pF for high frequency noise

During burst oscillation mode, this function operates

as follows:

reduction

Neglecting the effect of both input resistance and

forward voltage of rectifier diode, the reference value

of C1 voltage when Brown-In and Brown-Out

function is activated is calculated as follows:

 STR-A60××M and STR-A60××H:

This function is disabled during switching

operation stop period in burst oscillation mode.

When the BR pin voltage falls to V_BR(OUT)or less in

burst oscillation mode and the sum of switching

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* High-Speed Latch Release

When Overvoltage Protection function (OVP) or

Thermal Shutdown function (TSD) are activated,

the IC stops switching operation in latch mode.

Releasing the latch mode is done by decreasing the

VCC pin voltage below V_CC(OFF)or by decreasing









^B



R_A R



V_{DC (OP )}V_BR(TH) 1

(3)

R_C



the BR pin voltage below V_BR(OUT)

.

where,

In case of the DC line detection or without

Brown-in / Brown-Out function, the release time

depends on discharge time of C1 and takes longer

time until VCC pin voltage decreases to release

voltage.

V_DC(OP): C1 voltage when Brown-In and

Brown-Out function is activated

V_BR(TH): Any one of threshold voltage of BR pin

(see Table 9-1)

In case of the AC line detection, BR pin voltage is

decreased quickly when AC input voltage, V_AC, is

turned off, and thus the latch mode is quickly

released.

Table 9-1 BR pin threshold voltage

Value

Parameter

Symbol

(Typ.)

The components around BR pin:

Brown-In Threshold Voltage

Brown-Out Threshold Voltage

V_BR(IN)

5.6 V

・ R_Aand R_Bare 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.

V_BR(OUT)

4.8 V

V_DC(OP)can be expressed as the effective value of AC

input voltage using Equation (4).

1

・ R_Cis a few hundred kilohms

V_{AC(OP )RMS}



V_{DC (OP )}

(4)

2

・ R_Smust be adjusted so that the BR pin voltage is

more than V_BR(DIS)= 0.48 V when the VCC pin

voltage is V_CC(OFF)= 8.1 V

R_A, R_B, R_Cand C4 should be selected based on actual

operation in the application.

・ C4 is 0.22 μF to 1 μF for averaging AC input

voltage and high frequency noise reduction.

9.8.2 AC Line Detection

Neglecting the effect of input resistance is zero, the

reference effective value of AC input voltage when

Brown-In and Brown-Out function is activated is

calculated as follows:

Figure 9-12 shows BR pin peripheral circuit of AC

line detection. In order to detect the AC input voltage,

the time constant of R_Cand C4 should be longer than

the period of AC cycle. Thus the response of 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, the latch mode can be released

quickly*









^B





R_A R



(5)

V_{AC(OP )RMS}



V_BR(TH) 1

R_C

2



where,

V_AC(OP)RMS:The effective value of AC input voltage

when Brown-In and Brown-Out function

is activated

V_BR(TH)

:Any one of threshold voltage of BR pin

(see Table 9-1)

BR1

V_AC

R_A, R_B, R_Cand C4 should be selected based on

actual operation in the application.

R_A

R_B

3

R_S

VCC

U1

V_DC

C1

2

BR

C4

GND

3

R_C

Figure 9-12 AC line detection

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< Input Compensation Function >

9.9 Overcurrent Protection Function

(OCP)

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 V_OCP. Thus, the peak current has some

variation depending on the AC input voltage in OCP

state.

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 OCP threshold voltage.

During Leading Edge Blanking Time, the operation of

OCP is different depending on the products as follows.

In order to reduce the variation of peak current in

OCP state, the IC incorporates

Compensation function.

The Input Compensation Function is the function of

correction of OCP threshold voltage depending with AC

input voltage, as shown in Figure 9-15.

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).

The compensation signal depends on ON Duty. The

relation between the ON Duty and the OCP threshold

voltage after compensation V_OCP' is expressed as

Equation (6). When ON Duty is broader than 36 %, the

V_OCP' becomes a constant value V_OCP(H)= 0.9 V

a built-in Input

 STR-A60××HD:

During Leading Edge Blanking Time, the OCP

threshold voltage becomes V_OCP(LEB)= 1.55 V which

is higher than the normal OCP threshold voltage as

shown in Figure 9-13. 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.

 STR-A60××M and STR-A60××H:

OCP is disabled during Leading Edge Blanking Time.

When power MOSFET turns on, the surge voltage

width of S/OCP pin should be less than t_BW, as shown in

Figure 9-13. In order to prevent surge voltage, pay extra

attention to R_OCPtrace layout (refer to Section ).

In addition, if a C (RC) damper snubber of Figure

9-14 is used, reduce the capacitor value of damper

snubber.

1.0

V_OCP(H)

V_OCP(L)

t_BW

V_OCP(LEB)(STR-A60××HD)

V_OCP’

D_DPC

D_MAX

0.5

0

50

100

Surge pulse voltage width at turning on

Figure 9-13 S/OCP pin voltage

ON Duty (%)

Figure 9-15 Relationship between ON Duty and Drain

Current Limit after compensation

C（RC）

Damper snubber

T1

V_OCP' V_OCP(L) DPCONTime

D51

C51

C1

U1

ONDuty

 V_OCP(L) DPC

(6)

f_{OSC (AVG )}

7,8

D/ST

where,

C（RC）

Damper snubber

S/OCP

1

V_OCP(L): OCP Threshold Voltage at Zero ON Duty

DPC: OCP Compensation Coefficient

ONTime: On-time of power MOSFET

ONDuty: On duty of power MOSFET

R_OCP

f_OSC(AVG): Average PWM Switching Frequency

Figure 9-14 Damper snubber

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9.10 Overload Protection Function (OLP)

9.11 Overvoltage Protection (OVP)

Figure 9-16 shows the FB/OLP pin peripheral circuit,

and Figure 9-17 shows each waveform for OLP

operation. When the peak drain current of I_Dis limited

by OCP operation, the output voltage, V_OUT, decreases

and the feedback current from the secondary

photo-coupler becomes zero. Thus, the feedback current,

I_FB, charges C3 connected to the FB/OLP pin and the

FB/OLP pin voltage increases. When the FB/OLP pin

voltage increases to V_FB(OLP)= 8.1 V or more for the

OLP delay time, t_OLP= 68 ms or more, the OLP function

is activated, the IC stops switching operation.

When a voltage between VCC pin and GND pin

increases to V_CC(OVP)= 29 V or more, OVP function is

activated, the IC stops switching operation at the latched

state. In order to keep the latched state, when VCC pin

voltage decreases to V_CC(BIAS), the bias assist function is

activated and VCC pin voltage is kept to over the

V_CC(OFF)

.

Releasing the latched state is done by turning off the

input voltage and by dropping the VCC pin voltage

below V_CC(OFF), or by dropping the BR pin voltage below

V_BR(OUT)

.

During OLP operation, Bias Assist Function is

In case the 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 V_OUT(OVP)in OVP condition is calculated

by using Equation (7).

disabled. Thus, VCC pin voltage decreases to V_CC(OFF)

,

the control circuit stops operation. After that, the IC

reverts to the initial state by UVLO circuit, and the IC

starts operation when VCC pin voltage increases to

V_CC(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 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.

V_{OUT (NORMAL )}

V_OUT(OVP)





29 (V)

(7)

V_{CC(NORMAL )}

where,

V_OUT(NORMAL): Output voltage in normal operation

V_CC(NORMAL): VCC pin voltage in normal operation

U1

9.12 Thermal Shutdown Function (TSD)

VCC

5

GND FB/OLP

When the temperature of control circuit increases to

T_j(TSD)= 135 °C (min.) or more, Thermal Shutdown

function (TSD) is activated, the IC stops switching

operation at the latched state. In order to keep the

latched state, when VCC pin voltage decreases to

V_CC(BIAS), the bias assist function is activated and VCC

4

3

D2 R2

PC1

C3

C2

pin voltage is kept to over the V_CC(OFF)

.

D

Releasing the latched state is done by turning off the

input voltage and by dropping the VCC pin voltage

below V_CC(OFF), or by dropping the BR pin voltage below

Figure 9-16 FB/OLP pin peripheral circuit

V_BR(OUT)

.

Non-switching interval

VCC pin voltage

V_CC(ON)

V_CC(OFF)

FB/OLP pin voltage

V_FB(OLP)

t_OLP

Drain current,

I_D

Figure 9-17 OLP operational waveforms

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STR-A6000 Series

 FB/OLP Pin Peripheral Circuit

10. Design Notes

C3 is for high frequency noise reduction and phase

compensation, and should be connected close to these

pins. The value of C3 is recommended to be about

2200 pF to 0.01µF, and should be selected based on

actual operation in the application.

10.1 External Components

Take care to use properly rated, including derating as

necessary and proper type of components.

 VCC Pin Peripheral Circuit

The value of C2 in Figure 10-1 is generally

recommended to be 10µ to 47μF (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 the VCC pin voltage fluctuates in proportion to

the output current, I_OUT(see Figure 10-2), and the

Overvoltage Protection function (OVP) on the VCC

pin may be activated. This happens because C2 is

charged to a peak voltage on the auxiliary winding D,

which is caused by the transient surge voltage coupled

from the primary winding when the 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.

CRD clamp snubber

BR1

T1

VAC

R1

C6

R_A

R_B

C1

P

D1

D2 R2

5

8

7

D/ST D/ST NC VCC

U1

D

C2

C5

S/OCP BR

FB/OLP

4

GND

3

C(RC) damper snubber

1

2

PC1

C4

C3

R_C

R_OCP

Figure 10-1 The IC peripheral circuit

 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.

Without R2

VCC pin voltage

 S/OCP Pin Peripheral Circuit

In Figure 10-1, R_OCPis the resistor for the current

detection. A high frequency switching current flows

to R_OCP, and may cause poor operation if a high

inductance resistor is used. Choose a low inductance

and high surge-tolerant type.

With R2

Output current, I_OUT

 BR pin peripheral circuit

Because R_Aand R_B(see Figure 10-1) are applied high

voltage and are high resistance, the following should be

considered according to the requirement of the

application:

Figure 10-2 Variation of VCC pin voltage and power

 Snubber Circuit

In case the surge voltage of V_DSis large, the circuit

should be added as follows (see Figure 10-1);

▫ Select a resistor designed against electromigration,

or

▫ Use a combination of resistors in series for that to

reduce each applied voltage

・ A clamp snubber circuit of a capacitor-resistor-

diode (CRD) combination should be added on the

primary winding P.

See the section 9.8 about the AC input voltage

detection function and the components around BR pin.

When the detection resistor (R_A, R_B, R_C) value is

decreased and the C4 value is increased to prevent

unstable operation resulting from noise at the BR pin,

pay attention to the low efficiency and the slow

response of BR pin.

・ 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.

In case the damper snubber circuit is added, this

components should be connected near D/ST pin

and S/OCP pin.

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STR-A6000 Series

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.

 Peripheral circuit of secondary side shunt regulator

Figure 10-3 shows the secondary side detection circuit

with the standard shunt regulator IC (U51).

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 be selected based on actual operation in

the application.

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 10-4 shows the winding structural examples

of two outputs.

Winding structural example (a):

L51

T1

VOUT

(+)

D51

R54

R51

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.

PC1

R52

R55

C51

S

C53

C52 R53

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.

U51

R56

(-)

Figure 10-3 Peripheral circuit of secondary side shunt

regulator (U51)

Margin tape

 Transformer

Apply proper design margin to core temperature rise

by core loss and copper loss.

P1 S1 P2 S2 D

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.

Margin tape

Winding structural example (a)

Margin tape

P1 S1 D S2 S1 P2

Margin tape

▫ Thicken the wire gauge.

Winding structural example (b)

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)

Figure 10-4 Winding structural examples

10.2 PCB Trace Layout and Component

Placement

▫ The winding structure of auxiliary winding, D, is

susceptible to the noise of winding P.

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.

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

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

22

STR-A6000 Series

Figure 10-5 shows the circuit design example.

(4) R_OCPTrace Layout

(1) Main Circuit Trace Layout

R_OCPshould 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)

This is the main trace containing switching currents,

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.

which is close to the base of R_OCP

.

(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.

(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

separated from main trace and connected at a single

point grounding of point A in Figure 10-5 as close to

the R_OCPpin 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.

(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 C_f(about 0.1 μF to

1.0 μF) close to the VCC pin and the GND pin is

recommended.

(7) Thermal Considerations

Because the power MOSFET has a positive thermal

coefficient of R_DS(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.

(1)Main trace should be wide

trace and small loop

(6)Main trace of secondary side should

be wide trace and small loop

D51

T1

R1

C6

R_A

R_B

C1

P

D_ST

C51

(7)Trace of D/ST pin should be

wide for heat release

D1

S

D2 R2

5

8

7

C2

D/ST

D/ST NC

VCC

D

C5

U1

STR-A6000

(3) Loop of the power

supply should be small

S/OCP BR

FB/OLP

4

GND

3

1

2

R_OCP

(5)The components connected to

PC1

the IC should be as close to the

IC as possible, and should be

connected as short as possible

C3

C4 R_C

C_Y

A

(4)R_OCPshould be as close to S/OCP pin as

possible.

(2) Control GND trace should be connected at a

single point as close to the R_OCPas possible

Figure 10-5 Peripheral circuit example around the IC

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

23

STR-A6000 Series

11. Pattern Layout Example

The following show the PCB pattern layout example and the schematic of circuit using STR-A6000 series.

The above circuit symbols correspond to these of Figure 11-1.Only the parts in the schematic are used. Other parts

in PCB are leaved open.

Figure 11-1 PCB circuit trace layout example

L52

CN51

1

T1

D52

C57

OUT2(+)

OUT2(-)

R59

R60

R58

R61

C55

C56

L51

2

3

CN1

1

F1

L1

JW51

JW52

JW54

JW6

C12

L2

D1

D4

D2

D3

TH1

D51

C54

C1

C2

OUT1(+)

P1

C5

R54

R55

C13

C3

C4

R51

R1

3

PC1

C51

R52

R2

D7

C53 R57

S1

C52

U51

R53

JW2

R56

R7

R6

4

D2

D1

OUT1(-)

JW10

5

8

7

D8 R3

C8

JW4

JW31

CN31

1

D31

U1 D/ST D/ST

NC

VCC

C9

OUT4(+)

OUT4(-)

STR-A6000

C31

C32

R31

C10

2

BR

GND

S/OCP

1

FB/OLP

4

JW53

C11

JW21

2

3

CN21

1

U21

OUT

GND

JW8

3

D21

JW11

CP1

1

IN

OUT3(+)

OUT3(-)

JW3

JW7

JW9

2

C21

R5

R4

R21

C6

C7

C22

2

Figure 11-2 Circuit schematic for PCB circuit trace layout

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

24

STR-A6000 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.

 Power supply specification

IC

STR-A6059H

AC85V to AC265V

7.5W

5V

1.5A (max.)

Input voltage

Maximum output power

Output voltage

Output cirrent

 Circuit schematic

F1

1

L1

L51

R52

L2

D2

D3

D1

TH1

T1

D51

C55

3

VOUT(+)

5V/1.5A

C1

D4

R54

R55

R51

C4

D5

R4

R1

C2

3

S1

S2

C3

PC1

R57

C51

P1

C53

R53

U51

C52

R56

5

8

7

D6

R2

4

VOUT(-)

C5

D/ST

VCC

NC

R8

R9

U1

C8

D

STR-A6000

GND

S/OCP BR

FB/OLP

4

1

2

3

PC1

C7

C6

R7

R3

C9

TC_STR-A6000_4_R1

 Bill of materials

Recommended

Sanken Parts

Recommended

Sanken Parts

Symbol

Part type

Ratings⁽¹⁾

Symbol

Part type

Ratings⁽¹⁾

(3)

F1

Fuse

AC250V, 3A

3.3mH

R4

R7

Metal oxide

General

330kΩ, 1W

330kΩ

(2)

L1

L2

CM inductor

Inductor

(2)

(3)

470μH

R8

General

2.2MΩ

TH1

D1

NTC thermistor

General

Short

R9

General

2.2MΩ

600V, 1A

EM01A

PC1

U1

Photo-coupler

IC

PC123 or equiv

D2

General

STR-A6059H

FMB-G19L

－

See

D3

General

600V, 1A

EM01A

T1

Transformer

the specification

5μH

D4

D5

D6

C1

C2

C3

C4

C5

C6

C7

C8

C9

R1

General

600V, 1A

EM01A

EG01C

AL01Z

L51

D51

C51

C52

C53

C55

R51

R52

R53

R54

R55

R56

R57

Inductor

Fast recovery

Film, X2

1000V, 0.5A

200V, 1A

Schottky

Electrolytic

Ceramic

90V, 4A

680μF, 10V

0.1μF, 50V

330µF, 10V

1000pF, 1kV

220Ω

(2)

0.047μF, 275V

10μF, 400V

1000pF, 630V

22μF, 50V

0.01μF

Electrolytic

Ceramic

Electrolytic

Ceramic

General

Electrolytic

Ceramic

General

1.5kΩ

(2)

General

22kΩ

Ceramic

1000pF

General, 1%

General

Short

Ceramic

Open

10kΩ

Ceramic, Y1

General

2200pF, 250V

Open

10kΩ

(2)

Open

V_REF=2.5V

TL431 or equiv

R2

General

4.7Ω

U51

Shunt regulator

R3

General

1.5Ω, 1/2W

(1)

(2)

(3)

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.

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.

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

25

STR-A6000 Series

 Transformer specification

▫ Primary inductance, L_P

▫ Core size

：704 μH

：EI-16

▫ Al-value

：132 nH/N²(Center gap of about 0.26 mm)

▫ Winding specification

Winding

Symbol

P1

Number of turns (T)

73

Wire diameter (mm)

Construction

Two-layer,

solenoid winding

Single-layer,

solenoid winding

Single-layer,

solenoid winding

Primary winding

2UEW-φ0.18

Auxiliary winding

Output winding 1

Output winding 2

D

17

6

2UEW-φ0.18×2

TEX-φ0.3×2

S1

S2

Single-layer,

solenoid winding

6

V_DC

VOUT(+)

5V

P1

D

S1

S2

S1

VOUT(-)

D/ST

VCC

P1

D

Bobbin

Cross-section view

GND

: Start at this pin

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

26

STR-A6000 Series

OPERATING PRECAUTIONS

In the case that you use Sanken products or design your products by using Sanken products, the reliability largely

depends on the degree of derating to be made to the rated values. Derating may be interpreted as a case that an operation

range is set by derating the load from each rated value or surge voltage or noise is considered for derating in order to

assure or improve the reliability. In general, derating factors include electric stresses such as electric voltage, electric

current, electric power etc., environmental stresses such as ambient temperature, humidity etc. and thermal stress caused

due to self-heating of semiconductor products. For these stresses, instantaneous values, maximum values and minimum

values must be taken into consideration. In addition, it should be noted that since power devices or IC’s including power

devices have large self-heating value, the degree of derating of junction temperature affects the reliability significantly.

Because reliability can be affected adversely by improper storage environments and handling methods, please

observe the following cautions.

Cautions for Storage

 Ensure that storage conditions comply with the standard temperature (5 to 35°C) and the standard relative humidity

(around 40 to 75%); avoid storage locations that experience extreme changes in temperature or humidity.

 Avoid locations where dust or harmful gases are present and avoid direct sunlight.

 Reinspect for rust on leads and solderability of the products that have been stored for a long time.

Cautions for Testing and Handling

When tests are carried out during inspection testing and other standard test periods, protect the products from power

surges from the testing device, shorts between the product pins, and wrong connections. Ensure all test parameters are

within the ratings specified by Sanken for the products.

Remarks About Using Thermal Silicone Grease

 When thermal silicone grease is used, it shall be applied evenly and thinly. If more silicone grease than required is

applied, it may produce excess stress.

 The thermal silicone grease that has been stored for a long period of time may cause cracks of the greases, and it

cause low radiation performance. In addition, the old grease may cause cracks in the resin mold when screwing the

products to a heatsink.

 Fully consider preventing foreign materials from entering into the thermal silicone grease. When foreign material

is immixed, radiation performance may be degraded or an insulation failure may occur due to a damaged insulating

plate.

 The thermal silicone greases that are recommended for the resin molded semiconductor should be used.

Our recommended thermal silicone grease is the following, and equivalent of these.

Type

G746

YG6260 Momentive Performance Materials Japan LLC

SC102 Dow Corning Toray Co., Ltd.

Suppliers

Shin-Etsu Chemical Co., Ltd.

Soldering

 When soldering the products, please be sure to minimize the working time, within the following limits:

• 260 ± 5 °C 10 ± 1 s (Flow, 2 times)

• 380 ± 10 °C 3.5 ± 0.5 s (Soldering iron, 1 time)

 Soldering should be at a distance of at least 1.5 mm from the body of the products.

Electrostatic Discharge

 When handling the products, the operator must be grounded. Grounded wrist straps worn should have at least 1MΩ

of resistance from the operator to ground to prevent shock hazard, and it should be placed near the operator.

 Workbenches where the products are handled should be grounded and be provided with conductive table and floor

mats.

 When using measuring equipment such as a curve tracer, the equipment should be grounded.

 When soldering the products, the head of soldering irons or the solder bath must be grounded in order to prevent

leak voltages generated by them from being applied to the products.

 The products should always be stored and transported in Sanken shipping containers or conductive containers, or

be wrapped in aluminum foil.

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

27

STR-A6000 Series

IMPORTANT NOTES

 The contents in this document are subject to changes, for improvement and other purposes, without notice. Make

sure that this is the latest revision of the document before use.

 Application examples, operation examples and recommended examples described in this document are quoted for

the sole purpose of reference for the use of the products herein and Sanken can assume no responsibility for any

infringement of industrial property rights, intellectual property rights, life, body, property or any other rights of

Sanken or any third party which may result from its use.

 Unless otherwise agreed in writing by Sanken, Sanken makes no warranties of any kind, whether express or

implied, as to the products, including product merchantability, and fitness for a particular purpose and special

environment, and the information, including its accuracy, usefulness, and reliability, included in this document.

 Although Sanken undertakes to enhance the quality and reliability of its products, the occurrence of failure and

defect of semiconductor products at a certain rate is inevitable. Users of Sanken products are requested to take, at

their own risk, preventative measures including safety design of the equipment or systems against any possible

injury, death, fires or damages to the society due to device failure or malfunction.

 Sanken products listed in this document are designed and intended for the use as components in general purpose

electronic equipment or apparatus (home appliances, office equipment, telecommunication equipment, measuring

equipment, etc.).

When considering the use of Sanken products in the applications where higher reliability is required (transportation

equipment and its control systems, traffic signal control systems or equipment, fire/crime alarm systems, various

safety devices, etc.), and whenever long life expectancy is required even in general purpose electronic equipment

or apparatus, please contact your nearest Sanken sales representative to discuss, prior to the use of the products

herein.

The use of Sanken products without the written consent of Sanken in the applications where extremely high

reliability is required (aerospace equipment, nuclear power control systems, life support systems, etc.) is strictly

prohibited.

 When using the products specified herein by either (i) combining other products or materials therewith or (ii)

physically, chemically or otherwise processing or treating the products, please duly consider all possible risks that

may result from all such uses in advance and proceed therewith at your own responsibility.

 Anti radioactive ray design is not considered for the products listed herein.

 Sanken assumes no responsibility for any troubles, such as dropping products caused during transportation out of

Sanken’s distribution network.

 The contents in this document must not be transcribed or copied without Sanken’s written consent.

STR-A6000 - DS Rev.4.3

Mar. 13, 2015

SANKEN ELECTRIC CO.,LTD.

28


型号：	STR-A6000_15
厂家：	SANKEN ELECTRIC
描述：	Off-Line PWM Controllers with Integrated Power MOSFET
文件：	总28页 (文件大小：787K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

STR-A6000_15 [SANKEN]

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