Fairchild Semiconductor FAN3506 Datasheet

FAN3506

PC SMPS Secondar y Side Control IC

www.fairchildsemi.com

Features

• Few External Components

• Low Voltage Operation (Vcc_min=4.5V)

• Over Voltage Protection for 3.3V/5V/12V Output

• Two Protection Inputs (PT1, PT2)

• Fault Protection Output with Open Collector

• Power Supp ly on/off Delay Time Control (PSON)

• Latch Function Controlled by PSON and Protection

• Power Good Signal Genera tor with Hysteresis

• 300ms(Typ) Power Good Delay

• Programmable Shunt Regulator Trimmed to ±2%

• 16-Pin Dual In-line Package (16-DIP-300)

Block Diagram

V33

V12

Description

The FAN3506 is complete housekeeping circuitry for use in the secondary side of PC SMPS (Switched Mode Power Supply). It contains various functions, which are over voltage protection including two extra protection inputs, power supply on/off delay control and power good signal generator. Especially, it contains a programmable shunt regulator for output feedback and the reference voltage is trimmed to ±2%. The FAN3506 is available in 16-DIP.

16-DIP

FPO

TPSON

1.26V

lon

+ + + + +

_ +

COMP3

1.8V~0.6V

PT1

13 14

PT2

PSON

lil

+ _

COMP2

3.2V

1.4V

S R

1.26V

VREF

lchg

TPG

_ +

COMP6

1.8V~1.2V

loff

R11

R10

R12

11 12

PGI

_ _

COMP4

1.32V~1.26V

COMP5

1.32V~1.26V

GND

3.9V

Rev. 1.0.2

FAN3506

Pin Description

No Name I/O Function

1 V33 I +3.3V Output Voltage of SMPS Secondary Side 2 V5 I +5V Output Voltage of SMPS Secondary Side 3 V12 I +12V Output Voltage of SMPS Secondary Side

Supply Voltage. +5Vsb(+5V Standby Supply) is Recommended for Vcc.

5FPOO

6Rd -

7PSON I

8TPSON -

9PGO

10 TPG -

11 PGI I 12 GND - Ground

13 PT1 I Protection Input 1. This can be Used for an Adjustable OVP or Another Protection Input. 14 PT2 I Protection Input 2. This can be Used for an Adjustable OVP or Another Protection Input.

15 IK I

16 V

REF

The Operating Range is 4.5V~15V. Vcc=5V, Ta=25°C at test. Fault Protection Output(FPO) With Open Collector Structur e. This Signal Controls the

Primary Switch(PWM IC) Through an Opto-coupler. Maximum Current Rating is 20mA. When FPO = "Low", the Main SMPS is Operational and if FPO = "High", the Main S MPS is Turned-off.

OFF Delay Resistor. This Block is Made up of a Buffer With Vout = 1.258V. A Resistor Should be Connected to the Pin6 for Determination of Off Delay Current. The Recommended Value of Rd Resistor is 28kΩ at Ctpson=0.22uF. The off Delay Time is Gotten by Following Equation. Toff = [ Ctpson * (V8max-VthL) ] / (1.258V/Rrd)

Power Supply On/Off (Remote On/Off) Inpu t. It is TTL Operation a nd its Threshold Voltage is 1.4V. The Maximum Voltage of Pin7 is About 3.9V(Typ), With ABsolutely Maximum Voltage, 5.25v. If Pson Is Low, Fpo Is Low, Too. That Means The main SMPS is Operation(Active). When PSON is High, then FPO is High and the Main SMPS is off.

Power Supply On/Off Delay. Ton/Toff = 24ms/8ms(Typ) with Ctpson=0.22uF & Rd=28kΩ. Its High/Low Threshold Voltages 1.8V/0.6V and the Maximum Voltage After Full Charging is About 2.2V. So Vcharge = VthH = 1.8V and Vdischg = V8max - VthL =

1.6V. Each Delay Time is Decided by the Following Equations, Ton = (Ctpson*VthH) / Ion, Toff = [Ctpson*(V8max-VthL)] / (Vrd/Rrd) .

Power Good Signal Output with Open Collector. The Maximum Current Rating is 20mA. PG High Means that the Power is Good for Operation and PG low Means Power Fail.

PG Delay. Td = 300ms(Typ) with Ctpg=2.2uF. Th e Threshold Voltage is 1.8V and the Delay Time is Decided by the Following Equation, Td = (Ctpg * Vth) / Ichg = 1.8Ctpg / Ichg.

Power Good Signal Input. Its Threshold Voltage is 1.26V When the PGI Voltage Drops From High to Low.

Cathode of the Programmable Shunt Regulator. Absolute Min/Max Current Rating is 1mA/30mA.

Reference of Programmable Shunt Regulator. This Circuit is Prepared for Feedback of

Output Voltage as it Equals to KA431(LM431). It is Trimmed to ±2%.

FAN3506

Absolute Maximum Ratings

Parameter Symbol Value Unit

Supply Voltage V

4.5 ~ 15 V FPO (Fault Protection Output) Voltage VFPO 20 V FPO Maximum Current IFPO 20 mA PGI Maximum Voltage Vpgi 20 V PG Output Maximum Current Io(PG) 20 mA Cathode Voltage Vka 20 V Cathode Current for IK IK 1 ~ 30 mA Power Dissipation P Operating Temperature Range T Storage Temperature T

D OPR STG

-25 ~ +80 °°°°C

-65 ~ +150 °°°°C

Electrical Characteristics

= 5V, Ta = 25°°°°C, unless otherwise specified)

Parameter Symbol Test Conditions Min. Typ. Max. Unit PROTECTION SECTION

OVP Detecting Voltage for 3.3V V OVP Detecting Voltage for 5V V OVP Detecting Voltage for 12V V Protection Input Voltage 1 V Protection Input Voltage 2 V

POWER SUPPLY ON/OFF SECTION (PSON)

PSON Input Threshold Voltage V PSON Input Open Voltage V PSON Input Low Current lil PSON=0V 0 - -1 mA PSON Delay Charging Current lon PSON=TPSON=0V -10 -16 -24 uA Buffer Output Voltage VRd lsink=45uA, 200uA 1.21 1.26 1.31 V Pin8 Clamping Voltage V High Threshold for On/Off Delay (Note1) VthH TPSON : 0V to 2.2V 1.6 1.8 2.0 V Low Threshold for On/Off Delay (Note2) VthL TPSON : 2.2V to 0V 0.4 0.6 0.8 V Power Supply ON Delay Time (Note3) Ton Cpin8=0.22µF, Rd=28kΩ 16 26 36 msec Power Supply OFF Delay Time (Note4) Toff Cpin8=0.22µF, Rd=28kΩ 4 8 14 msec FPO Saturation Voltage V FPO Leakage Current lleak(FPO) FPO=20V 0 0.01 1 uA

33 PSON=0V 3.9 4.1 4.3 V

OVP

5 PSON=0V 5.7 6.1 6.5 V

OVP

12 PSON=0V 13.6 14.3 15.0 V

OVP

1 PSON=0V 1.21 1.26 1.31 V

2 PSON=0V 1.21 1.26 1.31 V

th ih

8max

(FPO) lo=10mA - 0.2 0.4 V

sat

PSON=0V : 0V to 2V 1 1.4 1.8 V PSON : Open 2 - 5.25 V

PSON=0V 2.0 2.2 2.4 V

FAN3506

Electrical Characteristics

(Continued)

(VCC= 5V, Ta = 25°C, unless otherwise specified)

Parameter Symbol Test Conditions Min. Typ. Max. Unit POWER GOOD SECTION

PGI Threshold Voltage V V33 Under Voltage Level V V5 Under Voltage Level V V12 Under Voltage Level V Pin10 Clamping Voltage V10

pgi

33 V33 : 3.3V to 2V 2.66 2.8 2.94 V

12 V12 : 12V to 9V 9.8 10.3 10.8 V

max

PGI : 1.5V to 1V 1.21 1.26 1.31 V

5 V5 : 5V to 3.5V 4.1 4.3 4.5 V

TPG : Open 3.4 3.9 4.4 V PG Delay Comparator Threshold Voltage Vth(TPG) TPG : 0V to 2.5V 1.5 1.8 2.1 V PG Delay Comparator Hysteresis Voltage HY TPG : 2.5V to 0V 0.3 0.6 0.9 V Charging Current for PG Delay lchg TPG = 0V -9 -15 -23 uA PG Delay Time Td(PG) Cpin10 = 2.2uF 100 300 500 msec PG Output Rising Time (Note5) Tr Cpin9 = 0.1uF - 1 - usec PG Output Falling Time (Note6) Tf Cpin9 = 0.1uF - 1 - usec PG Output Saturation Voltage Vsat(PG) lsink = 15mA - 0.2 0.4 V PG Output Leakage Current lleak(PG) V(PG) = 20V 0 0.01 1 uA

PROGRAMMABLE SHUNT REGULATOR (KA431) SECTION

Reference Input Voltage V

ref

IK = V

, IK = 1mA 2.45 2.50 2.55 V

REF

Load Regulation Vref IK = 1mA to 10mA - 5 15 mV Temperature Stability (Note7) ∆Vref/∆T Ta = -25 ~ +85°C-4.517mV Output Sinking Current Capability lsink - 10 25 - mA Gain Bandwidth (Note8) GBW GV = 1 - 1 - MHz

TOTAL DEVICE

Supply Current Icc PSON = 2V - 3 8 mA

Note :

1. Power Supply ON Delay (PSON :High → Low). Power Supply is Active when PSON is Low.

2. Power Supply OFF Delay (PSON :Low → High). Power Supply is Off when PSON is High.

3. Ton = (Cpin8 * Von) / lon = (Cpin8 * VthH) / lon

4. Toff = (Cpin8 * Voff) / loff = [Cpin8 * (V8max - VthL)] / (VRd / Rd) 5,6,7,8 : These parameters, although guaranteed, are but not 100% tested in production.

Block Description & Application Hints

1. OVP Block

FAN3506

R4 R6

V12

1.26V

+ +

VCC

SET of Latch

COMP1

PT1

PT2

V33

OVP function is simply realized by connecting Pin1, Pin2, Pin3 to each secondary output. R1,2,3,4,5,6 are internal resistors of the IC. Each OVP level is determined by resistor ratio and the typical values are 4V/6.1V/14.2V.

- OVP Detecting voltage for +3.3V . Vovp33 = (R1+R2)/R2 * 1.26V = 4.1V(Typ)

- OVP Detecting voltage for +5V . Vovp5 = (R3+R4)/R4 * 1.26V = 6.1V(Typ)

- OVP Detecting voltage for +12V . Vovp12 = (R5+R6)/R6 * 1.26V = 14.3V(Typ) Especially, Pin13 & Pin14 are prepared for extra OVP inputs or another protection signal, respectively. That is, if you want

over voltage protection of extra output voltage, then you can make a function with two external resistors.

- Threshold Voltage of Protection Input 1 : Vpt1 = 1.26V

- Threshold Voltage of Protection Input 2 : Vpt1 = 1.26V OVP function operates without delay time. In the case of OVP, system designer should know a fact that the main power can be

dropped after a little time because of system delay, even if FPO is triggered by OVP. So when the OVP level is tested with a set, you should check the secondary outputs(+3.3V/+5V/+12V) and FPO(Pin5)

simultaneously. you can know the each OVP level as checking each output voltage in just time that FPO is triggered from low to high.

+ 11 hidden pages