Fairchild FAN6754B service manual

FAN6754B Highly Integrated Green- Mode PWM Controller

FAN6754B — Highly Integrated Green-Mode PWM Controller

April 2011

Brownout and V

Adjustment by HV Pin

Limit

Features

 High-Voltage Startup  AC Input Brownout Protection with Hysteresis  Monitor HV to Adjust V

Limit

 Low Operating Current: 1.5mA  Linearly Decreasing PWM Frequency to 22KHz  Frequency Hopping to Reduce EMI Emission

 Fixed PWM Frequency: 65KHz  Peak-Current-Mode Control  Cycle-by-Cycle Current Limiting  Leading-Edge Blanking (LEB)  Internal Open-Loop Protection  GATE Output Maximum Voltage Clamp: 13V  V  V

Under-Voltage Lockout (UVLO)

DD

Over-Voltage Protection (OVP)

DD

 Programmable Over-Temperature Protection (OTP)  Internal Latch Circuit (OVP, OTP)  Open-Loop Protection (OLP); Restart for MR, Latch

for ML

 Built-in 8ms Soft-Start Function

Applications

General-purpose switch-mode power supplies and flyback power converters, including:

Description

The highly integrated FAN6754B PWM controller 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 and very light-load conditions, FAN6754B saves PWM pulses by entering deep burst mode. This burst mode function enables the power supply to meet international power conservation requirements.

FAN6754B integrates a frequency-hopping function internally to reduce EMI emission of a power supply with minimum line filters. Built-in synchronized slope compensation is accomplished by proprietary HV monitor to adjust V over universal AC input range. The gate output is clamped at 13V to protect the external MOSFET from over-voltage damage.

Other protection functions include AC input brownout protection with hysteresis, and V protection. For over-temperature protection, an external NTC thermistor can be applied to sense the external switcher’s temperature. When V activated, an internal latch circuit is used to latch-off the controller. The latch mode is reset when the VDD supply is removed.

FAN6754B is available in an 8-pin SOP package.

for constant output power limit

Limit

over-voltage

DD

OVP or OTP are

DD

 Power Adapters

Ordering Information

Operating

Part Number

FAN6754BMRMY

FAN6754BMLMY

Temperature

Package Packing Method

Range

-40 to +105°C 8-Pin, Small Outline Package (SOP) Tape & Reel

Application Diagram

FAN6754B — Highly Integrated Green-Mode PWM Controller

Internal Block Diagram

4 3

Line Voltage Sample Circuit

HV

Startup

VDD

7

UVLO

17V/10V

V

DD-OVP

I

RT

5

1.05V

0.7V

Figure 1. Typical Application

OVP

Latch

OTP

OLP for ML

Protection

Brownout Protection

V

Adjustment

Limit

Debounce

t

D-OTP1

Counter

t

D-OTP2

Counter

Internal

BIAS

OVP

OSC

Green

Mode

OTP

OLP

QS

R

Delay

1

GND

Figure 2. Functional Block Diagram

Re-Start

Protection

Soft-Start

Comparator

Current Limit

Comparator

PWM

Comparator

OLP

Comparator

OLP

OLP for MR

Soft

Driver

Soft-Start

V

Limit

Slope

Compensation

R

4.6V

NCHV

GATE

8

Circuit

Blanking

5V

3R

6

2

SENSE

FB

Marking Information

ZXYTT 6754MR BTPM

Pin Configuration

ZXYTT 6754ML BTPM

Figure 3. Top Mark

SOP-8

FAN6754B — Highly Integrated Green-Mode PWM Controller

F - Fairchild Logo

Z - Plant Code X - 1-Digit Year Code Y - 1-Digit Week Code TT - 2-Digit Die Run Code T - Package Type (M=SOP) P - Y: Package (Green) M - Manufacture Flow Code

Pin Definitions

Pin # Name Description

1 GND

2 FB

3 NC

4 HV

5 RT

6 SENSE

7 VDD

8 GATE

Ground. This pin is used for the ground potential of all the pins. A 0.1µF decoupling capacitor

placed between VDD and GND is recommended.

Feedback. The output voltage feedback information from the external compensation circuit is fed

into this pin. The PWM duty cycle is determined by this pin and the current-sense signal from Pin

6. FAN6754B performs open-loop protection (OLP); if the FB voltage is higher than a threshold voltage (around 4.6V) for more than 56ms, the controller latches off the PWM.

No Connection High-Voltage Startup. This pin is connected to the line input via a 1N4007 and 200k resistor to

achieve brownout and high/low line compensation. Once the voltage on the HV pin is lower than the brownout voltage, PWM output turns off. High/low line compensation dominates the cycle-bycycle current limiting to achieve constant output power limiting with universal input.

Over-Temperature Protection. An external NTC thermistor is connected from this pin to GND.

The impedance of the NTC decreases at high temperatures. Once the voltage on the RT pin drops below the threshold voltage, the controller latches off the PWM. If RT pin is not connected to NTC resistor for Over-Temperature Protection, a 100K series one resistor is recommended to ground to prevent from noise interference. This pin is limited by an internal clamping circuit.

Current Sense. This pin is used to sense the MOSFET current for the current-mode PWM and current limiting. The version doesn’t have internal SSCP function.

Supply Voltage. IC operating current and MOSFET driving current are supplied using this pin.

This pin is connected to an external bulk capacitor of typically 47µF. The threshold voltages for turn-on and turn-off are 17V and 10V, respectively. The operating current is lower than 2mA.

Gate Drive Output. The totem-pole output driver for the power MOSFET. It is internally clamped

below 13V.

GND

FB

NC

HV

Figure 4. Pin Configuration (Top View)

18

2

3

7

6

54

GATE

VDD

SENSE

RT

FAN6754B — 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.

Symbol Parameter Min. Max. Unit

V

DC Supply Voltage

VDD

VFB FB Pin Input Voltage -0.3 7.0 V

V

SENSE Pin Input Voltage -0.3 7.0 V

SENSE

VRT RT Pin Input Voltage -0.3 7.0 V

VHV HV Pin Input Voltage 500 V

PD

JA

Power Dissipation (T

Thermal Resistance (Junction-to-Air) 150

TJ Operating Junction Temperature -40 +125

T

Storage Temperature Range -55 +150

STG

TL Lead Temperature (Wave Soldering or IR, 10 Seconds) +260

ESD

Electrostatic Discharge Capability, All Pins Except HV Pin

Notes:

1. All voltage values, except differential voltages, are given with respect to the network ground terminal.

2. Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device.

3. ESD with HV pin: CDM=1000V and HBM=1000V.

(1,2)

30 V

＜50°C)

A

400 mW

C/W

C

Human Body Model; JESD22-A114

Charged Device Model; JESD22-C101

5500

V

2000

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. Typ. Max. Unit

TA Operating Ambient Temperature -40 +105 °C

RHV HV Startup Resistor 150 200 250

k

FAN6754B — Highly Integrated Green-Mode PWM Controller

Electrical Characteristics

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

Symbol Parameter Condition Min. Typ. Max. Unit

VDD Section

VOP Continuously Operating Voltage 24 V

V

Start Threshold Voltage 16 17 18 V

DD-ON

V

Minimum Operating Voltage 9 10 11 V

DD-OFF

V

I

DD-OLP

V

DD-LH

V

DD-AC

I

Startup Current V

DD-ST

I

DD-OP1

I

DD-OP2

ILH

I

DD-OLP

V

DD-OVP

t

D-VDDOVP

HV Section

Off Voltage 5.5 6.5 7.5 V

DD-OLP

Threshold Voltage on VDD Pin for Latch-Off Release Voltage

Threshold Voltage on VDD Pin for Disable AC Recovery to Avoid Startup Failed

Operating Supply Current, PWM Operation

Operating Supply Current, Gate Stop

3.5 4.0 4.5 V

V

– 0.16V 30 µA

DD-ON

=20V, FB=3V Gate

V

DD

DD-OFF

+2.8

Open

V

DD-OFF

+3.3

V

DD-OFF

+3.8

1.5 2.0 mA

VDD=20V, FB=3V 1.0 1.5 mA

Operating Current at PWM-Off Phase Under Latch-Off

VDD=5V 30 60 90 µA

Conduction

Internal Sink Current Under LatchOff Conduction

Over-Voltage Protection 24 25 26 V

DD

V

Over-Voltage Protection

DD

Debounce Time

V

+0.1V

DD-OLP

75 165 255 µs

170 200 230 µA

V

IHV Supply Current from HV Pin

I

Leakage Current after Startup

HV-LC

VAC=90V(VDC=120V),

=0V

V

DD

HV=700V, VDD=V

+1V

OFF

DD-

DC Source Series

V

Brownout Threshold

AC-OFF

R=200k to HV Pin

See Equation 1

DC Source Series

V

Brownin Threshold

AC-ON

R=200kΩ to HV Pin

See Equation 2

V

VAC

t

Line Voltage Sample Cycle

S-CYCLE

t

Line Voltage Hold Period 20 µs

H-TIME

t

PWM Turn-off Debounce Time

D-AC-OFF

AC-ON

- V

AC-OFF

DC Source Series R=200kΩ to HV Pin

FB > V

FB < V

FB > V

FB < V

220

FB-N

650

FB-G

65 75 85 ms

FB-N

180 235 290 ms

FB-G

2.0 3.5 5.0 mA

1 20 µA

92 102 112 V

104 114 124 V

6 12 18 V

µs

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