FAN6791 Fairchild Semiconductor, FAN6791 Datasheet

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FAN6791

Manufacturer Part Number
FAN6791
Description
The highly integrated FAN6791/3 dual PWM combination controller provides several features to enhance the performance of converters
Manufacturer
Fairchild Semiconductor
Datasheet

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Company
Part Number
Manufacturer
Quantity
Price
Part Number:
FAN6791NY
Manufacturer:
FAIRCHILD/仙童
Quantity:
100
Part Number:
FAN6791NY
Manufacturer:
FAIRCHILD/仙童
Quantity:
100
© 2008 Fairchild Semiconductor Corporation
FAN6791/3 • Rev. 1.0.3
FAN6791 / FAN6793
Highly Integrated, Dual-PWM Combination Controller
Features
Applications
General-purpose switch-mode power supplies and
flyback power converters, including:
High-Voltage Startup
Low Operating Current
Interleaved Stand-by PWM / Forward PWM Switching
Green Mode Stand-by PWM / Forward PWM
Linearly Decreasing Stand-by PWM Frequency to
20kHz
Remote On / Off
AC Brownout Protection
Forward PWM with Soft-Start
Frequency Hopping to Reduce EMI Emissions
Cycle-by-Cycle Current Limiting for Stand-by PWM /
Forward PWM
Leading-Edge Blanking for Stand-by PWM / Forward
PWM
Synchronized Slope Compensation for Stand-by
PWM / Forward PWM
GATE Output Maximum Voltage Clamp
V
V
Internal Open-Loop Protection for Stand-by PWM /
Forward PWM
Constant Power Limit for Stand-by PWM / Forward
PWM
PC-ATX Power Supplies
DD
DD
Over-Voltage Protection (OVP)
Under-Voltage Lockout (UVLO)
Description
The
combination controller provides several features to
enhance the performance of converters.
To minimize standby power consumption, a proprietary
green-mode function provides off-time modulation to
linearly decrease the switching frequency at light-load
conditions. To avoid acoustic-noise problems, the
minimum PWM frequency is set above 20kHz. This
green-mode function enables the power supply to meet
international power conservation requirements. With the
internal high-voltage startup circuitry, the power loss
due to bleeding resistors is also eliminated. To further
reduce
manufactured using the CMOS process, which allows
an operating current of only 6mA.
FAN6791/3 integrates a frequency-jittering function
internally to reduce EMI emissions of a power supply
with minimum line filters. The built-in synchronized slope
compensation
control. The proprietary internal line compensation
ensures constant output power limit.
FAN6791/3
including brownout protection, cycle-by-cycle current
limiting, and an internal open-loop protection circuit to
ensure safety should an open-loop or output short-
circuit failure occur. PWM output is disabled until V
drops below the UVLO lower limit when the controller
restarts. As long as V
OVP circuit is triggered.
highly
power
provides
integrated
achieves
consumption,
DD
many
exceeds ~24.5V, the internal
stable
FAN6791/3
protection
peak-current-mode
FAN6791/3
January 2010
www.fairchildsemi.com
dual
functions,
PWM
DD
is

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FAN6791 Summary of contents

Page 1

... To further reduce power consumption, manufactured using the CMOS process, which allows an operating current of only 6mA. FAN6791/3 integrates a frequency-jittering function internally to reduce EMI emissions of a power supply with minimum line filters. The built-in synchronized slope compensation achieves stable control ...

Page 2

... FAN6791NY 48% FAN6793NY 65% FAN6791MY 48% FAN6793MY 65% For Fairchild’s definition of Eco Status, please visit: http://www.fairchildsemi.com/company/green/rohs_green.html. © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 Operating Eco Temperature Status Range -40°C to +105°C Green 16-Pin Dual In-Line Package (DIP) -40°C to +105°C Green ...

Page 3

... Application Diagram © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 Figure 1. Typical Application 3 www.fairchildsemi.com ...

Page 4

... Block Diagram © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 Pattern Generator Figure 2. Function Block Diagram 4 www.fairchildsemi.com ...

Page 5

... Marking Information SOIC DIP Pin Configuration © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 – Fairchild Logo F Z – Plant Code X – 1-Digit Year Code Y – 1-Digit Week Code TT – 2-Digit Die Run Code T – Package Type (M:SOIC) P – Y: Green Package M – ...

Page 6

... Flyback PWM Gate Drive. The totem-pole output drive for the forward PWM MOSFET. This pin is 15 OFYB internally clamped under 16V to protect the MOSFET. Line-Voltage Detection. The pin is used for line compensation, for forward, and brownout 16 VRMS protection. © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 6 exceeds the DD www.fairchildsemi.com ...

Page 7

... Fairchild does not recommend exceeding them or designing to Absolute Maximum Ratings. Symbol T Operating Ambient Temperature A © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 Parameter < 50°C) A Human Body Model, JEDEC:JESD22-A114 (All Pins Except HV Pin) Charged Device Model, JEDEC:JESD22-C101 ...

Page 8

... Load Regulation of Reference △V REF1 Voltage Line Regulation of Reference △V REF2 Voltage I Maximum Current REF_MAX I V Short Current OS REF © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 Conditions Min. V – 0.16V DD V =15V; GATE Open DD V =15V; GATE Open =10mA REF ...

Page 9

... Circuit Protection OFYB-GATE Driver Flyback PWM Gate Output V OFYB-CLAMP Clamping Voltage V Output Voltage Low OL-OFYB V Output Voltage High OH-OFYB t Rising Time R-OFYB t Falling Time F-OFYB © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 Conditions Min. 50 2.4 0.8 130 (2) 100 1/3. Pin Open 5.0 4.2 53 2.4 60 1.8 1.2 ...

Page 10

... When activated, the output is disabled and the latch is turned off. 2. This is the threshold temperature for enabling the output again and resetting the latch after over-temperature protection has been activated. © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 Conditions FB Pin Open R =24kΩ ...

Page 11

... Figure 9. V vs. Temperature DD-ON 47.50 47.45 47.40 47.35 47.30 47.25 47.20 47.15 47.10 -40℃ -25℃ -10℃ 5℃ 20℃ 35℃ Figure 11. OPWM Maximum Duty Cycle vs. Temperature © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 10.0 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0 -40℃ -25℃ -10℃ 95℃ 110℃ 125℃ vs. Temperature 2.5 2.0 1.5 1.0 0.5 0.0 65℃ ...

Page 12

... PWM-VLIMIT RMS 0.815 0.810 0.805 0.800 0.795 0.790 0.785 0.780 -40℃ -25℃ -10℃ 5℃ 20℃ 35℃ Figure 19 =1V) vs. Temperature FYB-VLIMIT RMS © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 57.5 57.0 56.5 56.0 55.5 55.0 54.5 54.0 53.5 -40℃ -25℃ -10℃ vs. Temperature Figure 14. Falling Time ...

Page 13

... Typical Characteristics 66.1 66.0 65.9 65.8 65.7 65.6 65.5 -40℃ -25℃ -10℃ 5℃ 20℃ 35℃ Figure 21. OPWM Frequency vs. Temperature © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 66.3 66.2 66.1 66.0 65.9 65.8 65.7 65.6 50℃ 65℃ 80℃ 95℃ 110℃ 125℃ -40℃ -25℃ -10℃ Figure 22. OFYB Frequency vs. Temperature 13 5℃ 20℃ 35℃ 50℃ 65℃ ...

Page 14

... Oscillator Operation A resistor connected from the RI pin to the GND pin generates a constant current source for the FAN6791/3 controller. This current is used to determine the center PWM frequency. Increasing the resistance reduces PWM frequency. Using a 24kΩ resistor results in a corresponding 65kHz PWM frequency ...

Page 15

... RI Pin Open / Short Protection. The RI pin is used to set the switching frequency and internal current reference. The stand-by PWM and forward PWM stages are disabled whenever the RI pin is short or open. Open-Loop Protection. The stand-by PWM and forward PWM stages of FAN6791/3 is disabled whenever the FBFYB / FBPWM pin is open www.fairchildsemi.com ...

Page 16

... Reference Circuit © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 Figure 29. Reference Circuit 16 www.fairchildsemi.com ...

Page 17

... C25 C28 R10 R13 R14 R15 R17 © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 Component Reference C/0.47µF/X2 C/0.47µF/X2 C/471P/50V C/471P/50V C/102P/50V C/102P/50V C/102P/50V C/472/400V C/472/400V C/102P/50V C/10µF/50V C/104P/50V C/102P/1KV C/470µF/200V C/470µF/200V C/103P/1KV C/1000µ ...

Page 18

... 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/. © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 A 19.68 18.66 9 ...

Page 19

... 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/ © 2008 Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 19 www.fairchildsemi.com ...

Page 20

... Fairchild Semiconductor Corporation FAN6791 / FAN6793 • Rev. 1.0.3 20 www.fairchildsemi.com ...

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