FAN6862LTY - Fairchild - Product.Network

May 2012

FAN6862R/L • Rev. 1.0.1

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

FAN6862R / FAN6862L

Highly Integrated Green-Mode PWM Controller

Features

 Low Startup Current: 8µA

 Low Operating Current in Green Mode: 3mA

 Peak-Current-Mode Operation with Cycle-by-Cycle

Current Limiting

 PWM Frequency Continuously Decreasing with

Burst Mode at Light Loads

 VDD Over-Voltage Protection (OVP)

 Constant Output Power Limit (Full AC Input Range)

 Over-Temperature Protection (OTP)

 Fixed PWM Frequency (65KHz) with Frequency

Hopping

 Feedback Open-Loop Protection with 56ms Delay

 Soft-Start Time: 5ms

 400mA Driving Capability

Applications

General-purpose switch-mode power supplies and

flyback power converters, including:

 Power Adapters

 Open-Frame SMPS

 SMPS with Surge-Current Output, such as for

Printers, Scanners, and Motor Drivers

Description

A highly integrated PWM controller, FAN6862R/L

provides several features to enhance the performance

of flyback converters. To minimize standby power

consumption, a proprietary green-mode function

provides off-time modulation to continuously decrease

the switching frequency under light-load conditions.

Under zero-load conditions, the power supply enters

burst mode, which completely shuts off PWM output.

Output restarts just before the supply voltage drops

below the UVLO lower limit. This green-mode function

enables power supplies to meet international power

conservation requirements.

The FAN6862R/L is designed for SMPS and integrates

a frequency-hopping function that helps reduce EMI

emission of a power supply with minimum line filters.

The built-in synchronized slope compensation is

proprietary sawtooth compensation for constant output

power limit over universal AC input range. The gate

output is clamped at 18V to protect the external

MOSFET from over-voltage damage.

Other protection functions include VDD over-voltage

protection, over-temperature protection, and overload

protection. For over-temperature protection, an external

NTC thermistor can be applied to sense the ambient

temperature. When OVP, OTP, or OLP is activated, an

internal protection circuit switches off the controller.

Part Number OVP OTP OLP

FAN6862RTY Auto Restart Auto Restart Auto Restart

FAN6862LTY Latch Latch Latch

Ordering Information

Part Number Operating Temperature Range Package Packing Method

FAN6862RTY -40 to +105°C 6-Pin SSOT-6 Tape & Reel

FAN6862LTY -40 to +105°C 6-Pin SSOT-6 Tape & Reel

FAN6862R/L • Rev. 1.0.1 2

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Typical Application

Figure 1. Typical Application

Block Diagram

Figure 2. Block Diagram

FAN6862R/L • Rev. 1.0.1 3

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Marking Information

ABxTT

••••

---

Figure 3. Top Mark

Pin Configuration

Figure 4. Pin Assignments

Pin Definitions

Pin # Name Function Description

1 GND Ground Ground

2 FB Feedback

The FB pin provides the output voltage regulation signal. It provides feedback to the

internal PWM comparator for control of the duty cycle. This pin also provide for

OLP: if VFB is larger than the trigger level and remains for a long time, the controller

stops and restarts.

3 RT

Temperature

Detection

An external NTC thermistor is connected from this pin to GND for over-temperature

protection. The impedance of the NTC decreases at high temperatures. Once the

voltage of the RT pin drops below a threshold, PWM output is disabled.

4 SENSE Current

Sense

This pin senses the voltage across a resistor. When the voltage reaches the internal

threshold, PWM output is disabled. This activates over-current protection. This pin

also provides current amplitude information for current-mode control.

5 VDD Power Supply Power supply

6 GATE Driver Output The totem-pole output driver for driving the power MOSFET.

ABx: ABA: FAN6862LTY

ABC: FAN6862RTY

TT: Wafer Lot Code

: Year Code

_ _ _: Week Code

FAN6862R/L • Rev. 1.0.1 4

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Absolute Maximum Ratings

Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be

operable above the recommended operating conditions and stressing the parts to these levels is not recommended.

In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability.

The absolute maximum ratings are stress ratings only. All voltage values, except differential voltages, are given with

respect to GND pin.

Symbol Parameter Min. Max. Unit

VDD Supply Voltage 30 V

VL Input Voltage to FB, SENSE, RT Pin -0.3 7.0 V

PD Power Dissipation at TA<50°C 300 mW

ΘJC Thermal Resistance (Junction-to-Case) 115 °C/W

TJ Operating Junction Temperature -40 +150 °C

TSTG Storage Temperature Range -55 +150 °C

TL Lead Temperature, Wave Soldering, 10 Seconds +260 °C

ESD Human Body Model, JESD22-A114 3.00 kV

Charge Device Model, JESD22-C101 1.25

Recommended Operating Conditions

The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended

operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not

recommend exceeding them or designing to Absolute Maximum Ratings.

Symbol Parameter Min. Max. Unit

TA Operating Ambient Temperature -40 +105 °C

FAN6862R/L • Rev. 1.0.1 5

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Electrical Characteristics

VDD = 15V and TA = 25°C unless otherwise noted.

Symbol Parameter Test Condition Min. Typ. Max. Unit

VDD Section

VDD-OP Continuously Operating Voltage 24 V

VDD-ON Turn-On Threshold Voltage 15 16 17 V

VDD-OFF Turn-Off Voltage 7.5 8.5 9.5 V

VDD-OVP V

DD Over-Voltage Protection (Latch-Off) 24 25 26 V

VDD-LH Threshold Voltage for Latch-Off Release 3 4 5 V

IDD-ST Startup Current VDD-ON–0.16V 8 30 μA

IDD-OP Normal Operating Supply Current CL=1nF 3 4 mA

IDD-BM Green-Mode Operating Supply Current GATE Open,

VFB=VFB-G 2.5 mA

VDD-OVP V

DD Over-Voltage Protection 24 25 26 V

tD-VDDOVP V

DD OVP Debounce Time 30 50 μs

IDD-LH Latch-Off Holding Current VDD=5V 40 65 μA

Feedback Input Section

AV Input-Voltage to Current-Sense Attenuation 1/4.0 1/3.5 1/3.0 V/V

ZFB Input Impedance 5.5 kΩ

VFB-OPEN FB Pin Open Voltage 5.0 5.2 5.4 V

VFB-OLP Threshold Voltage for Open-Loop Protection 4.3 4.6 4.9 V

tD-OLP Open-Loop Protection Delay Time 53 56 60 ms

Current Sense Section

tPD Delay to Output 100 250 ns

tLEB Leading-Edge Blanking Time 270 360 ns

VSTHFL Flat Threshold Voltage for Current Limit Duty>51% 0.47 0.50 0.53 V

VSTHVA Valley Threshold Voltage for Current Limit Duty=0% 0.41 0.44 0.47 V

VSLOPE Slope Compensation Duty=DCYMAX 0.273 V

tSOFT-START Period During Startup Time 2.50 4.00 5.25 ms

Oscillator Section

fOSC Normal PWM Frequency

Center Frequency VFB>VFB-N 62 65 68

kHz

Hopping Range VFB≥VFB-N ±3.7 ±4.2 ±4.7

Hopping Range*1 V

FB=VFB-G ±2.9

thop-1 Hopping Period 1*1 V

FB≥VFB-N 4.4 ms

thop-3 Hopping Period 3*1 V

FB=VFB-G 11.5 ms

fOSC-G Green Mode Minimum Frequency 18.0 22.5 25.0 kHz

VFB-N FB Threshold Voltage For Frequency

Reduction 2.3 2.5 2.7 V

VFB-G FB Voltage at fOSC-G 1.9 2.1 2.3 V

VFB-ZDC FB Threshold Voltage for Zero Duty 1.7 V

fDV Frequency Variation vs. VDD Deviation VDD=11.5V to 20V 0 0.02 2.00 %

fDT Frequency Variation vs. Temperature

Deviation TA= -40 to +105°C 2 %

Continued on the following page…

FAN6862R/L • Rev. 1.0.1 6

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Electrical Characteristics (Continued)

VDD = 15V and TA = 25°C unless otherwise noted.

Symbol Parameter Test Condition Min. Typ. Max. Unit

PWM Output Section

DCYMAX Maximum Duty Cycle 65 70 75 %

VOL Output Voltage Low VDD=15V, IO=50mA 1.5 V

VOH Output Voltage High VDD=8V, IO=50mA 6 V

tR Rising Time CL=1nF 150 200 ns

tF Falling Time CL=1nF 35 80 ns

VCLAMP Gate Output Clamping Voltage VDD=20V 15.0 16.5 18.0 V

Over-Temperature Protection (OTP) Section

IRT Output Current of RT Pin 92 100 108 μA

VOTP

Threshold Voltage for Over-Temperature

Protection TA=25°C 0.97 1.02 1.07 V

tDOTP Over-Temperature Debounce Time VFB=VFB-N 15 17 19 ms

VFB=VFB-G

(1) 51

VOTP2

2nd Threshold Voltage for Over-

Temperature Protection TA=25°C 0.60 0.70 0.75 V

tDOTP2 2nd Over-Temperature Debounce Time 80 100 190 μs

Note:

1. Guarantee by design.

FAN6862R/L • Rev. 1.0.1 7

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Typical Performance Characteristics

15

15.4

15.8

16.2

16.6

17

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

V

DD-ON

(V)

7.5

7.9

8.3

8.7

9.1

9.5

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

V

DD-OFF

(V)

Figure 5. Turn-On Threshold Voltage (VDD-ON)

vs. Temperature

Figure 6. Turn-Off Threshold Voltage (VDD-OFF)

vs. Temperature

2.5

2.9

3.3

3.7

4.1

4.5

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

IDD-OP (mA)

24

24.4

24.8

25.2

25.6

26

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

VDD-OVP (V)

Figure 7. Operating Current (IDD-OP) vs. Temperature Figure 8. VDD Over-Voltage Protection (VDD-OVP)

vs. Temperature

62

63

64

65

66

67

68

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

f

OSC

(KHz)

2.2

2.3

2.4

2.5

2.6

2.7

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

VFB-N (V)

Figure 9. Center Frequency (fOSC) vs. Temperature Figure 10. FB Threshold Voltage for Frequency

Reduction (VFB-N) vs. Temperature

FAN6862R/L • Rev. 1.0.1 8

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Typical Performance Characteristics (Continued)

1.8

1.9

2

2.1

2.2

2.3

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

VFB-G (V)

4.3

4.4

4.5

4.6

4.7

4.8

4.9

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

VFB-OLP (V)

Figure 11. FB Voltage at fOSC-G (VFB-G) vs. Temperature Figure 12. Threshold Voltage for Open-Loop

Protection (VFB-OLP) vs. Temperature

53

54

55

56

57

58

59

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

tD-OLP (mS)

0.4

0.44

0.48

0.52

0.56

0.6

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

V

STHFL

(V)

Figure 13. Open-Loop Protection Delay Time (tD-OLP)

vs. Temperature

Figure 14. Flat Threshold Voltage for Current Limit

(VSTHFL) vs. Temperature

0.35

0.39

0.43

0.47

0.51

0.55

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

V

STHVA

(V)

2

3

4

5

6

7

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

tSOFT-START (mS)

Figure 15. Valley Threshold Voltage for Current Limit

(VSTHVA) vs. Temperature

Figure 16. Period during Startup (tSOFT-START)

vs. Temperature

FAN6862R/L • Rev. 1.0.1 9

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Typical Performance Characteristics (Continued)

67

68

69

70

71

72

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

DCYMAX (%)

80

100

120

140

160

180

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

tR (nS)

Figure 17. Maximum Duty Cycle (DCYMAX)

vs. Temperature

Figure 18. Rising Time (tR) vs. Temperature

20

30

40

50

60

70

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

tF (nS)

80

88

96

104

112

120

-40 -30 -15 0 25 50 75 85 100 125

Temperature (ºC)

IRT (μA)

Figure 19. Falling Time (tF) vs. Temperature Figure 20. Output Current of RT Pin (IRT)

vs. Temperature

FAN6862R/L • Rev. 1.0.1 10

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Operation Description

Startup Operation

Figure 21 shows a typical startup circuit and transformer

auxiliary winding for a typical application. Before

FAN6862R/L begins switching operation, it consumes

only startup current (typically 8μA) and the current

supplied through the startup resistor charges the VDD

capacitor (CDD). When VDD reaches the turn-on voltage

of 16V (VDD-ON), FAN6862R/L begins switching and the

current consumed increases to 3mA. Then the power

required is supplied from the transformer auxiliary

winding. The large hysteresis of VDD (8.5V) provides

more holdup time, which allows using a small capacitor

for VDD. The startup resistor is typically connected to AC

line for a fast reset of latch protection.

Figure 21. Startup Circuit

Green-Mode Operation

The FAN6862R/L uses feedback voltage (VFB) as an

indicator of the output load and modulates the PWM

frequency, as shown in Figure 22, such that the

switching frequency decreases as load decreases. In

heavy-load conditions, the switching frequency is

65KHz. Once VFB decreases below VFB-N (2.5V), the

PWM frequency starts to linearly decrease from 65KHz

to 22.5kHz to reduce the switching losses. As VFB

decreases below VFB-G (2.1V), the switching frequency is

fixed at 22.5kHz and FAN6862R/L enters “deep” green

mode, where the operating current decreases to 2.5mA

(maximum), further reducing the standby power

consumption. As VFB decreases below VFB-ZDC (1.7V),

FAN6862R/L enters burst-mode operation. When VFB

drops below VFB-ZDC, switching stops and the output

voltage starts to drop, which causes the feedback

voltage to rise. Once VFB rises above VFB-ZDC, switching

resumes. Burst mode alternately enables and disables

switching, thereby reducing switching loss in standby

mode, as shown in Figure 23.

VV FB -NFB -G FB

V

Frequency

FB-ZDC

V

PWM

Frequency

65kHz

+4.2kHz

-4.2kHz

22.5kHz

+2.9kHz

-2.9kHz

Figure 22. PWM Frequency

Figure 23. Burst-Mode Operation

Frequency Hopping

EMI reduction is accomplished by frequency hopping,

which spreads the energy over a wider frequency range

than the bandwidth measured by the EMI test

equipment. An internal frequency hopping circuit

changes the switching frequency between 60.8kHz and

69.2kHz with a period of 4.4ms, as shown in Figure 24.

Figure 24. Frequency Hopping

FAN6862R/L • Rev. 1.0.1 11

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Protections

Self-protective functions include VDD Over-Voltage

Protection (OVP), Open-Loop / Overload Protection

(OLP), Over-Current Protection (OCP), Short-Circuit

Protection, and Over-Temperature Protection (OTP).

FAN6862R uses auto-restart mode protections and

FAN6862L uses latch-mode protections.

Auto-Restart Mode Protection: Once a fault condition

is detected, switching is terminated and the MOSFET

remains off. This causes VDD to fall because no more

power is delivered from auxiliary winding. When VDD falls

to VDD-OFF (8.5V), the protection is reset and the

operating current reduces to startup current, which

causes VDD to rise. FAN6862R resumes normal

operation when VDD reaches VDD-ON (16V). In this

manner, the auto-restart can alternately enable and

disable the switching of the MOSFET until the fault

condition is eliminated (see Figure 25).

Latch-Mode Protection: Once this protection is

triggered, switching is terminated and the MOSFET

remains off. The latch is reset only when VDD is

discharged below 4V by unplugging AC power line.

Figure 25. Auto-Restart Operation

Over-Current Protection (OCP)

FAN6862R/L has over-current protection thresholds. It is

for pulse-by-pulse current limit, which turns off the

MOSFET for the remainder of the switching cycle when

the sensing voltage of MOSFET drain current reaches

the threshold. The other threshold is for the over-current

protection, which shuts down the MOSFET gate when

the sensing voltage of MOSFET drain current is above

the threshold longer than the shutdown delay (56ms).

Open-Loop / Overload Protection (OLP)

When the upper branch of the voltage divider for the

shunt regulator (KA431 shown) is broken, as shown in

Figure 26, no current flows through the opto-coupler

transistor, which pulls up the feedback voltage to 5.2V.

When the feedback voltage is above 4.6V longer than

56ms, OLP is triggered. This protection is also triggered

when the SMPS output drops below the nominal value

longer than 56ms due to the overload condition.

Figure 26. OLP Operation

VDD Over-Voltage Protection (OVP)

VDD over-voltage protection prevents IC damage caused

by over voltage on the VDD pin. The OVP is triggered

when VDD reaches 25V. A debounce time (typically

30µs) prevents false triggering by switching noise.

Over-Temperature Protection (OTP)

The OTP circuit is composed of current source and

voltage comparators. Typically, an NTC thermistor is

connected between the RT and GND pins. Once the

voltage of this pin drops below a threshold of 1.02V,

PWM output is disabled after tDOTP debounce time. If this

pin drops below 0.7V, it triggers the latch-off protection

immediately after tDOTP2 debounce time.

FAN6862R/L • Rev. 1.0.1 12

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Constant Output Power Limit

FAN6862R/L has saw-limiter for pulse-by-pulse current

limit, which guarantees almost constant power limit over

different line voltages of universal input range.

The conventional pulse-by-pulse current limiting scheme

has a constant threshold for current limit comparator,

which results in a higher power limit for high line voltage.

FAN6862R/L has a sawtooth current limit threshold that

increases progressively within a switching cycle, which

provides lower current limit for high line and makes the

actual power limit level almost constant over different

line voltages of universal input range, as shown in

Figure 27.

Higher current limit for low line

Lower current limit for high line

MOSFET

Drain current

Sawtooth current limit threshold

Figure 27. Sawtooth Current Limiter

Leading-Edge Blanking (tLEB)

Each time the power MOSFET is switched on, a turn-on

spike occurs across the sense-resistor caused by

primary-side capacitance and secondary-side rectifier

reverse recovery. To avoid premature termination of the

switching pulse, a leading-edge blanking time is built in.

During this blanking period (360ns), the PWM

comparator is disabled and cannot switch off the gate

driver. Thus, RC filter with a small RC time constant is

enough for current sensing.

Figure 28. Current Sense R-C Filter

Soft-Start

The FAN6862R/L has an internal soft-start circuit that

increases pulse-by-pulse current-limit comparator

inverting input voltage slowly after it starts. The typical

soft-start time is 5ms. The pulsewidth to the power

MOSFET is progressively increased to establish the

correct working conditions for transformers, rectifier

diodes, and capacitors. The voltage on the output

capacitors is progressively increased with the intention

of smoothly establishing the required output voltage. It

also helps prevent transformer saturation and reduces

the stress on the secondary diode during startup.

FAN6862R/L • Rev. 1.0.1 13

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Typical Application Circuit (Netbook Adapter by Flyback)

Application Fairchild Devices Input Voltage Range Output

Netbook Adapter FAN6862R/L 90~265VAC 19V/2.1A (40W)

Features

 High efficiency (>85.3% at full load) meeting EPS regulation with enough margin

 Low standby (Pin<0.15W at no-load condition)

 Soft-start time: 5ms

82

83

84

85

86

87

88

89

90

91

25% 50% 75% 100%

Load (% )

Eff iciency ( %)

O v er Current Pr otecti o n

1

1.5

2

2.5

3

3.5

4

4.5

5

90V 115V 230V 264V

Vac(V)

Io(A)

Figure 29. Measured Efficiency and Over-Current Protection

Figure 30. Schematic of Typical Application Circuit

85.29% (Energy star V2.0)

230VAC 50Hz (89.47% avg)

115VAC 60Hz (89.15% avg)

FAN6862R/L • Rev. 1.0.1 14

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Typical Application Circuit (Continued)

Transformer Specification

 Core: RM 8

 Bobbin: RM 8

Figure 31. Transformer Diagram

NO Terminal WIRE Ts

INSULATION BARRIER

S F Ts Primary Secondary

N1 11 10 0.25*1 9 3

N2 3 2 0.25* 1 33 1

11 COPPER SHIELD 1.2 3

N3 Fly- Fly+ 0.5* 2 12 1

11 COPPER SHIELD 1.2 3

N4 2 1 0.25 * 1 33 4

CORE ROUNDING TAPE 3

Pin Specification Remark

Primary-Side Inductance 3－1 920µH ±5% 100kHz, 1V

Primary-Side Effective Leakage 3－1 15µH Maximum Short One of the Secondary Windings

FAN6862R/L • Rev. 1.0.1 15

FAN6862R/L — Highly Integrated Green-Mode PWM Controller

Physical Dimensions

Figure 32. 6-Pin, SUPERSOT6 “SSOT-6”, JEDEC MO-193, 1.6mm Wide Package

Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner

without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or

obtain the most recent revision. Package specifications do not expand the terms of Fairchild’ s worldwide terms and conditions, specifically the

warranty therein, which covers Fairchild products.

Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings:

http://www.fairchildsemi.com/packaging/.

FAN6862R/L • Rev. 1.0.1 16

FAN6862R/L — Highly Integrated Green-Mode PWM Controller