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KA3505

PC SMPS Supervisory IC
Features
· · · · · · · · · · · · · PC Power Supply Output Monitor Circuitry Few External Components Over Voltage Protection for 3.3V/5V/12V Output Under Voltage Protection for 3.3V/5V/12V Output With Delay Time Over Current Protection for 3.3V/5V/12V Output With Delay Time Fault Protection Output With Open Collector Output Power Supply on/off Delay Time Control (PSON) Power Good Signal Generator With Hysteresis Open Collector PG Output 300ms Power Good Delay Current Sense Setting Function With RI Latch Function Controlled by PSON and Protection Input 16-Pin Dual In-line Package

Description
The KA3505 is complete output supervisory circuitry intended for use in the secondary side of the switched mode power supply. It provides all the functions necessary to monitor and control the output of the power supply system. Power good signal generator, Remote on and off control, some precision protection features against over-voltage, under-voltage and over-current are implemented. It directly senses all the output rails for OVP and UVP without any external dividers. As for output control, Power Good Output (PGO) and Fault Protection Output (FPO) are also included. Utilizing a minimum number of external components, the KA3505 offers a simple and cost effective solution, greatly reducing PCB board space for power supply system.

OCP (Over Current Protection)
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 output inductor that is located in the secondary output of SMPS.

FPO (Fault Protection Output)
Fault Protection Output indicates the fault condition as protection signal. When fault state occurs, the main power is to be turned-off and the PGO signal goes LOW. NORMAL = "LOW", FAULT = "HIGH"

OVP (Over Voltage Protection)
It has OVP functions for +3.3V, +5V, +12V outputs. The circuit is made up of a comparator with three detecting inputs.

PGO (Power Good Output)
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 delay time is programmed by a timing capacitor connected to TPG pin of KA3505. The power good output should be low state before the output voltage is out of regulation at turn-off. NORMAL = "HIGH", FAULT = "LOW"

UVP (Under Voltage Protection)
It also has UVP functions for +3.3V, +5V, +12V outputs. The block is made up of a comparator with three detecting inputs.

Remote ON/OFF
Remote on/off section is used to control SMPS externally. If a high signal is supplied to the remote on/off input, FPO 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 with 0.1µF external capacitor.
16-DIP

1

Rev. 1.0.1
©2002 Fairchild Semiconductor Corporation

KA3505

Internal Block Diagram
VS33
1

VS5 VS12
2 3

RI
11

Vcc
5

FPO PGI
6 4

Start Up
Internal Bias

Bandgap Reference
Vref VBG =1.25V RI=62K Iref(20µA) ICHG(PG)=15 µA
9

OVP Detector
Vref

UVP Detector
Vref ICHG(PROT)=20 µA COMP4 S Q R Q1 COMP7 UVP Detector Output

PGO

COMP8 Q3 1.8 ~ 0.6V Q2

IS12

14

COMP1 Iref × 5 (100µA)

1.8~ 0.6V 1.25V
On/Of f Delay Con t rol

COMP6

IS5

15

COMP2 Iref × 5 (100µA)

COMP5 1.4V 1.8~ 0.6V

IS33

16

COMP3 Iref × 5 (100µA)
13 7 8 12 10

T PROT PSON

T PSON

GND

T PG

Absolute Maximum Ratings
Parameter Supply Voltage Input Voltage FPO Voltage FPO Maximum Current Operating Temperature Storage Temperature Range Power Dissipation Symbol VCC Vinput VFPO IFPO Topr Tstg PD Value 15 ~ 30 30 30 20 -25 ~ +85 -65 ~ +150 1 Unit V V V mA °C °C W

2

KA3505

Pin Assignments : KA3505

VS33 1 VS5 2 VS12 3 PGI 4 Vcc 5 FPO 6 PSON 7 TPSON 8

16 15

IS33 IS5 IS12 TPROT GND RI TPG PGO

K A 3 5 0 5

14

13

12

11

10

9

3

KA3505

Pin Definitions
Pin No.
1 2 3 4 5 6

Name
V33 V5 V12 PGI VCC FPO

Pin Function Description Over and Under Voltage Protection Input for the 3.3V. It directly senses the 3.3V rail without any external divider. Over and Under Voltage Protection Input for the 5V. It directly senses the 5V rail without any external divider. Over and Under Voltage Protection Input for the 12V. It directly senses the 12V rail without any external divider. Power Good Signal Generator Input. It should be supplied from a bulk dependent voltage in order to detect power on and off state. Supply voltage. Its recommended operating voltage is ranged from 15V to 30V. Fault Protection Output (Open Collector Output). This pin indicates the fault condition. When fault state occurs, the PGO signal goes Low. Normal = 'Low", Fault = "High". Remote on/off input. It does TTL operation and its threshold voltage is 1.4V. In case of open circuit, the voltage at this pin is High (5.0V). If PSON = "Low", then FPO = "Low". It means the main SMPS is working. When PSON = "High or Open", then FPO = "High" and the main SMPS stops to work. Timing pin for PSON delay. Ton/Toff=8ms/24ms (Typ.) with Cpson=0.1µF externally. PSON On Delay Time (Ton) is measured as PSON input goes Low to High. PSON Off Delay Time (Toff) can be measured reversely. Power Good Output Signal (Open Collector). PGO = "High" means "Power Good" for operation and PGO = "Low" means "Power Fail". Timing pin for PGO delay. TPG = 270ms (Typ.) with CPG = 2.2µF externally. The high/low threshold voltages are 1.8V/0.6V and the voltage of pin10 would be charged up to 2.9V for noise margin. OCP current sense setting pin. The reference voltage at this pin is set to 1.25V internally.You can fix the OCP reference current by using RI resistor. Ground Timing pin for under voltage protection and over current protection blank-out time. Its threshold voltage is 1.8V and clamped at 2.9V after full charging. Target of delay time is 38ms and it is realized through external capacitor (C=0.47µF). Current sense input for +12V. This pin is connected to the current sensing resistor or inductor. You can define OCP offset voltage for +12V by using RI resistor externally. If you connected RI resistor of 62k at Pin11 to ground, the reference current(Iref) should be 20µA. After that, you can make a constant OCP offset voltage (VOFFSET = RO × 5 × Iref). In case the voltage drop (=IO.12 × RS) of the sense resistor or inductor is larger than offset voltage, FPO becomes "High" after some delay time and the main SMPS is turned-off. So the over current level is determined by following equation. (IO.12 = VOFFSET/ RS) See application note for details. Current sense input for +5V. You can make the +5V OCP function as previous method in IS12 (Pin14). Current sense input for +3.3V. You can also make the +3.3V OCP function as previous method in IS12 (Pin14).

7

PSON

8

TPSON

9

PGO

10

TPG

11 12 13

RI GND TPROT

14

IS12

15 16

IS5 IS33

4

KA3505

Electrical Characteristics
(VCC = 20V, -25°C < Ta < 85°C, unless otherwise specified) Characteristic Symbol PROTECTION SECTION Over Voltage Protection for 3.3V VOVP33 Over Voltage Protection for 5V VOVP5 Over Voltage Protection for 12V VOVP12 Under Voltage Protection for 3.3V VUVP33 Under Voltage Protection for 5V VUVP5 Under Voltage Protection for 12V VUVP12 Offset Voltage of OCP Comparator Voffset Charging Current for OCP, UVP Delay ICHG(PROT) 3.3, 5, 12V Over Current Delay Time TD(OCP) 3.3, 5, 12V Under Voltage Delay Time TD(UVP) POWER SUPPLU ON/OFF SECTION (PSON) Note PSON Input Threshold Voltage VTH(PSON) PSON Open Voltage VOPEN(PSON) PSON Input Low Current ILOW(PSON) ON Delay Time TON(PSON) OFF Delay Time TOFF(PSON) FPO SECTION FPO Saturation Voltage VSAT(FPO) FPO Leakage Current VLKG(FPO) Test Conditions VPSON = 0V VPSON = 0V VPSON = 0V VPSON = 0V VPSON = 0V VPSON = 0V VPSON = 0V C = 0.47µF C = 0.47µF PSON: "H" "L" PSON: Open VPSON = 0V C = 0.1µF C = 0.1µF IFPO = 10mA VFPO = 20V Min. 3.9 5.7 13.6 2.69 4.1 9.8 -3 -15 24 24 1 4 4 16 Typ. 4.1 6.1 14.3 2.83 4.3 10.3 -21 38 38 1.4 8 24 0.2 0.01 Max. 4.3 6.5 15.0 2.97 4.5 10.8 3 -30 57 57 1.8 5.25 -1.6 14 34 0.4 1 Unit V V V V V V mV µA msec msec V V mA msec msec V µA

Electrical Characteristics (Continued)
(VCC = 20V, -25°C < Ta < 85°C, unless otherwise specified) Characteristic POWER GOOD SECTION PG Input Threshold Voltage Hysteresis Voltage 1 Hysteresis Voltage 2 Charging Current for PG Delay PG Delay Time PG Output Saturation Voltage TOTAL DEVICE Stand-by Supply Current Symbol VIN(PG1) HY1 HY2 ICHG(PG) TD(PG) VSAT(PG) ICC Test Conditions PG: "H""L" COMP7 COMP4, 6, 8 C = 2.2µF IPG = 10mA Min. 1.20 10 0.6 -9 150 Typ. 1.25 40 1.2 -14 270 0.2 5 Max. 1.30 80 -22 450 0.4 10 Unit V mV V µA msec V mA

Note: 1. It does TTL operation and its threshold voltage is 1.4V. 2. Power Supply ON Delay Time (Ton) is measured as PSON input goes "Low" to "High". 3. Power Supply OFF Delay Time (Toff) is measured as PSON input goes "High" to "Low".

5

KA3505

Timing / Housekeeping / Control

Remote on/off

Toff Delay

Ton Delay

Output Voltage (3.3V, 5V, 12V) PGO
PG Delay PG Delay

FPO
Operating Mode Stand-by Mode

Vcc

PGI Detection Point Main Power Switch ON

Power on/off

OFF

6

KA3505

Test Circuit

1 VS33 2 VS5 3 VS12 4 PGI 5 Vcc
20V 10

IS 3 3 16 IS 5

15

6 FPO 7 PSON
0.1µF

K A 3 5 0 5

IS12 14 T PROT 13 GND 12 RI

0. 47µF

11
62 2.2µF

TPG S 10 PGO 9

8 TPSON

5V 1

7

KA3505

Typical Characteristics

Icc
0.006 20 0.005
Icc=4.881mA Vcc=20V

VOVP33

0.004

15

Icc[A]

0.003

FPO Voltage[V]
0 10 20 30 40

10

0.002

5

0.001 0

0.000

3.4

3.6

3.8

4.0

4.2

4.4

4.6

Vcc[V]

3.3V Output Voltage[V]

Figure 1. VCC - ICC
VOVP5

Figure 2. Over Voltage Protection for 3.3V
VOVP12

20

20

15

15

FPO Voltage[V]

10

FPO Voltage[V]
5.4 5.6 5.8 6.0 6.2 6.4 6.6

10

5

5

0

0

13.0

13.5

14.0

14.5

15.0

5V Output Voltage[V]

12V Output Voltage[V]

Figure 3. Over Voltage Protection for +5V

Figure 4. Over Voltage Protection for +12V
VUVP5

VUVP33

20

20

15

15

PGO Voltage[V]
2.5 2.6 2.7 2.8 2.9 3.0

PGO Voltage[V]

10

10

5

5

0

0

4.0

4.1

4.2

4.3

4.4

4.5

3.3V Output Voltage[v]

5V Output Voltage[V]

Figure 5. Under Voltage Protection for +3.3V

Figure 6. Under Voltage Protection for +5V

8

KA3505

Typical Characteristics (Continued)
VUVP12

VTH.PSON

20

20

15

15

10

PGO Voltage[V]
9.4 9.6 9.8 10.0 10.2 10.4 10.6 10.8 11.0 11.2

PGO Voltage[V]

10

5

5

0

0

0

1

2

3

4

5

12V Output Voltage[V]

PSON Voltage[V]

Figure 7. Under Voltage Protection for +12V
ION.OFF
0.000010
20

Figure 8. PSON Input Threshold Voltage

PGI

0.000005

0.000000

15

-0.000005

PGO Voltage[V]

ION.OFF[A]

10

-0.000010

5

-0.000015
0

-0.000020 0 1 2 3 4 5

1.0

1.1

1.2

1.3

1.4

1.5

PSON Voltage[V]

PGI Voltage[V]

Figure 9. PS On/Off Delay Current
HY1

Figure 10. PG Input Threshold Voltage

HY2

20

20

15

PGO Voltage[V]

10

PGO Voltage[V]
1.0 1.1 1.2 1.3 1.4 1.5

15

10

5

5

0

0

0.0

0.5

1.0

1.5

2.0

2.5

PGI Voltage[V]

TPG Voltage[V]

Figure 11. Hysteresis Voltage 1

Figure 12. Hysteresis Voltage 2

9

KA3505

Voltage Mode Application Schemata
D1 L1 L4

D2 AC Input FUSE C2 1000uF

1uF R2

C5

C8 1000uF

-

+ C1 220uF M1 D3 L2 L5

D4 R1 0.27 C3 1000uF

1uF R3

C6

R5 C9 1000uF

D5

L3

L6

D6 C4 1000uF

1uF R4

C7

C10 1000uF

R6

+5Vsb 5 5 6 6 7 8

KA38XX
4 3 2 1

C15

R12 R7 Vcc R15

C14 10nF R13 10

TL431

R8 R10

C11 8 0.1uF 7 10 6 11 5 12 4 13 3 14 2 15 1 16DIP 16

KA3505
R14 10 D7 R15 330 Q1 R11 REMOTE ON/OFF +5Vsb POWER GOOD C12 2.2uF R9 C13 62 0.47uF R16 9

10

KA3505

Current Mode Application Schematic
D1 L1 L4

D2 AC Input FUSE C2 1000uF

1uF R2

C5

C8 1000uF

-

+ C1 220uF M1 D3 L2 L5

D4 R1 0.27 C3 1000uF

1uF R3

C6

R5 C9 1000uF

D5

L3

L6

D6 C4 1000uF

1uF R4

C7

C10 1000uF

R6

+5Vsb 5 5 6 6 7 8

KA38XX
4 3 2 1

C15

R12 R7 Vcc R15

C14 10nF R13 10

TL431

R8 R10

C11 8 0.1uF 7 10 6 11 5 12 4 13 3 14 2 15 1 16DIP 16

KA3505
R14 10 D7 R15 330 Q1 R11 REMOTE ON/OFF +5Vsb POWER GOOD C12 2.2uF R9 C13 62 0.47uF R16 9

11

KA3505

Mechanical Dimensions
Package Dimensions in millimeters

16-DIP
( #1 #16 0.81 ) 0.032 6.40 ±0.20 0.252 ±0.008

19.80 MAX 0.780

19.40 ±0.20 0.764 ±0.008

#8

#9

7.62 0.300

3.25 ±0.20 0.128 ±0.008

0.38 0.014 MIN

5.08 MAX 0.200

3.30 ±0.30 0.130 ±0.012

0~15°

0.25 ­0.05 0.010 ­0.002
+0.004

+0.10

12

2.54 0.100

0.46 ±0.10 0.018 ±0.004

1.50 ±0.10 0.059 ±0.004

KA3505

Ordering Information
Product Number KA3505 Package 16-DIP Operating Temperature -25°C ~ +85°C

13

KA3505

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: 1. 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.
www.fairchildsemi.com 10/29/02 0.0m 001 Stock#DSxxxxxxxx 2002 Fairchild Semiconductor Corporation

2. 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.