FAN7585SN

FAN7585SN Datasheet

FAN7585

Part	Datasheet
FAN7585SN	FAN7585SN (pdf)

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FAN7585 Intelligent Voltage Mode PWM IC • Complete PWM Control and House Keeping Circuitry • Few External Components • Precision Voltage Reference Trimmed to 2% • Dual Output for Push-Pull Operation • Each Output TR for 200mA Sink Current • Variable Duty Cycle by Dead Time Control • Soft Start Capability by Using Dead Time Control • Double Pulse Suppression Logic • Over Voltage Protection for 3.3V/5V/12V • Under Voltage Protection for 3.3V/5V/12V • Over Current Protection for 3.3V/5V/12V • One More External Input for Various Protection PT • Remote On/Off Control Function PS-ON • Latch Function Controlled by Remote and Protection Input • Power Good Signal Generator with Hysteresis • PC Power Supply 24-SDIP 2003 Fairchild Semiconductor Corporation The FAN7585 is a fixed frequency improved performance pulse width modulation control circuit with complete housekeeping circuitry for use in the secondary side of SMPS Switched Mode Power Supply . It contains various functions, which are overvoltage protection, undervoltage protection, over current protection, remote on/off control, power good signal generator, etc. OVP Over Voltage Protection Section It has OVP functions for +3.3V,+5V,+12V outputs and PT. The circuit is made up of a comparator with four detecting inputs and without hysteresis voltage. Especially, PT Pin19 is prepared for an extra OVP input or another protection signal. UVP Under Voltage Protection Section It also has UVP functions for +3.3V, +5V, +12V outputs. The block is made up of a comparator with three detecting inputs and without hysteresis voltage. OCP Over Current Protection Section It has precision OCP functions for +3.3V, +5V, +12V outputs. The block is made up of three comparators with current source setting function. Two inputs of each OCP comparator are connected to both sides of current sensing inductor that is located in the secondary output of SMPS. Remote On/Off Section The remote on/off section is used to control SMPS externally. If a high signal or open state is supplied to the remote on/off input, PWM signal becomes a high state and all secondary outputs are grounded. The remote on/off signal is transferred with some on-delay and off-delay time of 8ms, 24ms respectively. Precision Reference Section The reference voltage is trimmed to 4.9V Vref 5.1V PG Power Good Signal Generator Section The power good signal generator is to monitor the voltage level of power supply for safe operation of a microprocessor having some delay time at turn-on. The power good output should be low state before the output voltatge is out of regulation at turn-off. FAN7585 Internal Block Diagram RT/CT 7 COMP 2 E/A - 3 E/A + 4 DTC 21 Vref 12 Vcc 1 DET 9 OSCILLATOR PWM CONTROL DQ CK Q 1.25V Vref Start Up DEAD TIME CONTROLER 0.1V Delay Controller 1.4V OVP COMP INTERNAL BIAS Vref Vref Iref1=Vref/RI Vref V5 1.8V!"0.6V Ichag PG H GENERATOR COMP3 1.8V!"0.6V COMP2 1.25V Ordering Information Product Number FAN7585 Package 24-SDIP Operating Temperature -25°C ~ 85°C DISCLAIMER FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS. LIFE SUPPORT POLICY FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein: Life support devices or systems are devices or systems which, a are intended for surgical implant into the body, or b support or sustain life, and c whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user. A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. 5/13/03 0.0m 001 2003 Fairchild Semiconductor Corporation

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FAN7585

Intelligent Voltage Mode PWM IC
• Complete PWM Control and House Keeping Circuitry
• Few External Components
• Precision Voltage Reference Trimmed to 2%
• Dual Output for Push-Pull Operation
• Each Output TR for 200mA Sink Current
• Variable Duty Cycle by Dead Time Control
• Soft Start Capability by Using Dead Time Control
• Double Pulse Suppression Logic
• Over Voltage Protection for 3.3V/5V/12V
• Under Voltage Protection for 3.3V/5V/12V
• Over Current Protection for 3.3V/5V/12V
• One More External Input for Various Protection PT
• Remote On/Off Control Function PS-ON
• Latch Function Controlled by Remote and Protection

Input
• Power Good Signal Generator with Hysteresis
• PC Power Supply
24-SDIP
2003 Fairchild Semiconductor Corporation

The FAN7585 is a fixed frequency improved performance pulse width modulation control circuit with complete housekeeping circuitry for use in the secondary side of SMPS Switched Mode Power Supply . It contains various functions, which are overvoltage protection, undervoltage protection, over current protection, remote on/off control, power good signal generator, etc.

OVP Over Voltage Protection Section It has OVP functions for +3.3V,+5V,+12V outputs and PT. The circuit is made up of a comparator with four detecting inputs and without hysteresis voltage. Especially, PT Pin19 is prepared for an extra OVP input or another protection signal.

UVP Under Voltage Protection Section It also has UVP functions for +3.3V, +5V, +12V outputs. The block is made up of a comparator with three detecting inputs and without hysteresis voltage.

OCP Over Current Protection Section It has precision OCP functions for +3.3V, +5V, +12V outputs. The block is made up of three comparators with current source setting function. Two inputs of each OCP comparator are connected to both sides of current sensing inductor that is located in the secondary output of SMPS.

Remote On/Off Section The remote on/off section is used to control SMPS externally. If a high signal or open state is supplied to the remote on/off input, PWM signal becomes a high state and all secondary outputs are grounded. The remote on/off signal is transferred with some on-delay and off-delay time of 8ms, 24ms respectively.

Precision Reference Section The reference voltage is trimmed to 4.9V Vref 5.1V

PG Power Good Signal Generator Section The power good signal generator is to monitor the voltage level of power supply for safe operation of a microprocessor having some delay time at turn-on. The power good output should be low state before the output voltatge is out of regulation at turn-off.

FAN7585

Internal Block Diagram

RT/CT 7 COMP 2 E/A - 3 E/A + 4

DTC 21 Vref 12 Vcc 1

DET 9

OSCILLATOR

PWM CONTROL

DQ CK Q
1.25V

Vref Start Up

DEAD TIME CONTROLER
0.1V

Delay Controller
1.4V

OVP COMP

INTERNAL

BIAS

Vref

Vref Iref1=Vref/RI

Vref

V5 1.8V!"0.6V

Ichag

PG H GENERATOR

COMP3
1.8V!"0.6V

COMP2
1.25V
Ordering Information

Product Number FAN7585

Package 24-SDIP

Operating Temperature -25°C ~ 85°C

DISCLAIMER

FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN NEITHER DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.

LIFE SUPPORT POLICY

FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR CORPORATION. As used herein:

Life support devices or systems are devices or systems which, a are intended for surgical implant into the body, or b support or sustain life, and c whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury of the user.

A critical component in any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.
5/13/03 0.0m 001 2003 Fairchild Semiconductor Corporation

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Datasheet ID: FAN7585SN 513985