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KA3504
PC SMPS Supervisory IC
Features
* * * * * * * * * * * * PC Power Supply Output Monitor Circuitry Few External Components Over Voltage Protection for 3.3V / 5V / 12V Output 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 KA3504 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 and over-current are implemented. It directly senses all the output rails for OVP 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 KA3504 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 prorammed by a timing capacitor connected to TPG pin of KA3504. The power good output should be low state before the output voltage is out of regulation at turn-off. NORMAL = "HIGH", FAULT = "LOW"
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 0.1mF external capacitor.
16-DIP
1
Rev. 1.0.0
(c)2001 Fairchild Semiconductor Corporation
KA3504
Internal Block Diagram
RI
11 Internal Bias
Vcc
5 Start Up Bandgap Reference Vref
FPO PGI
6 4
VS12
3 OVP Detector
VBG=1.26V
VS5 2 VS33 1
Vref
Iref=20uA ICHG(PG)=15uA
Vref COMP8 COMP1
ICHG(PROT)=20uA
9
PGO
S Q R
S Q1 COMP7 Q2
1.8V !" 0.6V
Q3
IS12
14
Iref*5 (100uA)
COMP4
1.8V !" 0.6V
COMP2
COMP5
IS5 1 5
On/Off Delay Control
1.25V COMP6
Iref*5 (100uA)
1.4V
IS33 1 6
Iref*5 (100uA)
1.8V !" 0.6V
COMP3
13
7
8
12
10
TPROT PSON
TPSON
GND
TPG
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 10 ~ 30 30 30 20 -20 ~ +85 -65 ~ +150 1 Unit V V V mA C C W
2
KA3504
Pin Assignments : KA3504
VS33 VS5 VS12 PGI Vcc FPO
1
16 IS33 15 IS5
2
3
4
5
6
PSON 7 TPSON 8
K A 3 5 0 4
14 IS12 13 TPROT
12 GND 11 RI
10 TPG 9 PGO
3
KA3504
Pin Defintions
Pin No.
1 2 3 4 5 6
Name
VS33 VS5 VS12 PGI VCC FPO
Pin Function Description Over Voltage Protection Input for the 3.3V. It directly senses the 3.3V rail without any external divider. Over Voltage Protection Input for the 5V. It directly senses the 5V rail without any external divider. Over 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 10V 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=0.1F 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 = 2.2F 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=0.47F). 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 62 at Pin11 to ground, the reference current(Iref) should be 20A. After that, you can make a constant OCP offset voltage (VOFFSET = RO x 5 x Iref). In case the voltage drop (=IO.12 x 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
KA3504
Electrical Characteristics
(VCC = 20V, -25C < Ta < 85C, 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 Offset Voltage of OCP Comparator Voffset Charging Current for OCP Delay ICHG(PROT) 3.3, 5, 12V Over Current Delay Time TD(OCP) POWER SUPPLU ON/OFF SECTION (PSON) Note PSON Input Threshold VTG 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 C = 0.47F PSON: "H" "L" PSON: Open VPSON = 0V C = 0.1F C = 0.1F IO = 10mA VFPO = 20V Min. 3.9 5.7 13.6 -3 -15 24 1 4 4 16 Typ. 4.1 6.1 14.3 -21 38 1.4 8 24 0.2 0.01 Max. 4.3 6.5 15.0 3 -30 57 1.8 5.25 -1.6 14 34 0.4 1 Unit V V V mV A msec V V mA msec msec V A
Electrical Characteristics
(VCC = 20V, -25C < Ta < 85C, 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 = 2.2F VPG = 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 A 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
KA3504
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
KA3504
Test Circuit
F A K N A 3 3 5 0 5 4 0 4
7
KA3504
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
ION.OFF
0.000010
20
Figure 4. Over Voltage Protection for +12V
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 5. PS On/Off Delay Current
Figure 6. PG Input Threshold Voltage
8
KA3504
Typical Characteristics (Continued)
HY1
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 7. Hysteresis Voltage 1
Figure 8. Hysteresis Voltage 2
9
KA3504
Application Circuit
B+
1 R27 2 C103
Q2
TX1 1 L1 D5 D6 F1 P C109 C110 TX2 4 C112 R28 2 N 1 C111 D8 Q3 L5 C113 2 SW2 C106 3 L3 D7 C107 + C104
L2 V12
C105 L4 V5 C108 L6 V33 C114
D9 C115 1 D11 10 Q4 C1 8,9 TX4 2 3 1 C119 7 Q5 C2 1 6 D13 R38 R41 D14 C124 D15 FB Vref R44 Vcc FPO Q6 C125 R45 U6 1 2 3 4 5 6 1 R51 C126 1 R52 7 8 2 2 KA7500 C1 1 R54 C2 1 R56 2 2 Vcc EA1(+) EA2(+) EA1(-) EA2(-) COMP DTC Ct Rt GND C1 Vref OC Vcc C2 E2 E1 16 15 R46 14 13 12 11 C127 10 RT2 9 R53 R47 2 Vref 2 U5 R42 C123 R43 C122 2 1 5 R39 2 1 1 R32 2 2
Vcc1
U4 Vcc 1 R29 2 R31 3 R34 4 C117 5 6 R35 7 C120 8 VS33 VS5 VS12 PGI Vcc FPO PSON Tpson IS33 IS5 IS12 Tprot GND RI Tpg PGO 16 15 14 13 12 R36 11 R37 10 9 C121 KA3504 PSON R40 Vcc
D10 R30 2 1 R33 D12
Lp1 Ls
B+
TX3 C116
C118 M1 PWM IC PGO
1
FPO
V33
V12
V5
R49 R48
R50
FB
R55
10
KA3504
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
2.54 0.100
0.46 0.10 0.018 0.004
1.50 0.10 0.059 0.004
11
KA3504
Ordering Information
Product Number KA3504 Package 16-DIP Operating Temperature -25C ~ +85C
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 11/30/01 0.0m 001 Stock#DSxxxxxxxx 2001 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.

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