www.fairchildsemi.com
FAN7680
PC Power Supply Outputs Monitoring IC
Features
Description
• PC Power Supply Output Monitor Circuitry
• Few External Components
• Over Voltage Protection for 3.3V, 5V and 12V(Vcc)
Outputs
• Under Voltage Protection for 3.3V, 5V and 12V(Vcc)
Outputs with Delay Time
• Fault Protection Output with Open Drain Output
• Open Drain Power Good Output
• 300ms Power Good Delay
• 38ms PSON On/Off Debounce
• 73us Debounce
• 2.3ms PSON to FPO Turn Off Delay
• Latch Function Controlled by PSON and Protection
Inputs
The FAN7680 is a complete output supervisory circuitry
intended for use in the secondary side of a switched mode
power supply. It provides over voltage protection (OVP),
under voltage protection (UVP), fault protection output
(FPO), remote On/Off (PSON), latch, internal delay circuits
and power good signal generator to monitor and control the
output of the switching power supply system. As for output
control, power good output(PGO) and fault protection output(FPO) are included. It directly senses all the output rails
for OVP and UVP without external dividers. The FAN7680
offers a simple and cost effective solution with minimum
number of external components and greatly reduces PCB
board space for power supply.
8-DIP
Typical Application
• PC Power Supply
1
8-SOP
1
OVP
FPO
The FAN7680 has OVP functions for +3.3V, +5V,
+12V(Vcc) outputs. This block is made up of three comparators with two inputs and resistor dividers. One input of a
comparator is connected to a reference voltage and another
input is connected to a resistor divider.
The FPO(Fault Protection Output) is a signal which indicates
the system fault condition according to protection signals.
When a fault state is occured, the FPO signal becomes high
and the PGO signal becomes low and the main power is to be
turned off.
Normal State; "Low"
Fault State; "High"
UVP
The FAN7680 also has UVP functions for +3.3V, +5V,
+12V(Vcc) outputs. This block is made up of three comparators with two inputs and resistor dividers. One input of a
comparator is connected to a reference voltage and another
input is connected to a resistor divider.
PSON
The remote on/off(PSON) section is for controlling the
SMPS externally. When a high signal is applied to the PSON
input, the FPO signal becomes a high state and all secondary
outputs are grounded. The remote on/off signal is transferred
with some on/off debounce time.
PGO
The power good signal generator provides a signal according
to output voltage conditions of a power supply for safe operation of a secondary system. The power good output should
be low state before the output voltage is out of regulation at
turn-off of the input power switch.
Normal State ; "High"
Fault State ; "Low"
Rev. 1.0.0
©2003 Fairchild Semiconductor Corporation
FAN7680
Internal Block Diagram
Vcc
Start-up
PSON
3.6V
REF.
clr
Delay
2.3ms
Vref
Oscillator
POR
CLK
CLK
Reset
VCC 7
R
VS5 6
UVP L
R
L
H
VS33 5
Delay
75ms
R
Debounce
73us
CLK
L
L
3
FPO
4
PSON
8
PGO
2
GND
L
S
Q
H
L
CLK
clr
L
R
L
PGI_O
Vcc
150uA
3.6V
OVP L
PSON L
L
Debounce
38ms
R
L
CLK
Vref
3.6V
PSON
L
UVP
L
PGI 1
H
R
H
PGI_O
CLK
CLK
Debounce
73us
H
clr
H
Q
H
Delay
300ms
L
L
L
L
Vref
Typical Applicatin Circuit
5Vsb
PGI
PGO
+12V
PSON
1 PGI
PGO
8
2 GND
VCC
7
5Vsb
3 FPO
VS5
6
+5V
VS33
5
+3.3V
4 PSON
FAN7680
2
FAN7680
Pin Assignments
GND
2
FPO
3
PSON 4
YWW
1
FAN7680
PGI
8
PGO
7
VCC
6
VS5
5
VS33
YWW :Work Week Code
Pin Definitions
Pin Number
Pin Name
I/O
Pin Function Description
1
PGI
I
Power Good Input
2
GND
-
Ground
3
FPO
O
Low Active Fault Protection Output, Open Drain Output Stage
4
PSON
I
Remote On/Off Control Input
5
VS33
I
3.3V Output Voltage Input
6
VS5
I
5V Output Voltage Input
7
VCC
I
Supply Voltage and 12V Output Voltage Input
8
PGO
O
Power Good Output Signal
3
FAN7680
Absolute Maximum Ratings
(Note2,3)
Parameter
Symbol
Value
Supply Voltage
VCC
16
V
Supply Current
ICC
1
mA
8
V
VPSON, VS5
Input Voltage
VS33, VPGI
VPGO
8
VFPO
16
TO
-40 ~ +125
°C
Storage Temperature
TS
-65 ~ +150
°C
Power Dissipation
PD
1
W
Output Voltage
Operating Temperature
Recommended Operating Conditions
Characteristic
Symbol
Supply Voltage
VCC
Input Voltage
Output Voltage
Output Sink Current
Supply Voltage Rising Time
4
Unit
V
(Note2,3)
Test Condition
Min.
Max.
Unit
15
V
7
V
VPGO
7
V
VFPO
15
V
IFPO
30
mA
IPGO
10
mA
4
VPSON , VS5,
VS33, VPGI
tr
Note1
1
Typ.
ms
FAN7680
Electrical Characteristics
(VCC = 5V, Ta=25°C, unless otherwise specified)
Over Voltage Protection, Under Voltage Protection and FPO
Characteristic
Over Voltage Threshold
Under Voltage Threshold
Symbol
Test Condition
Min.
Typ.
Max.
VS33OV
3.9
4.1
4.3
VS5OV
5.8
6.1
6.4
12V(VCC)OV
13.3
13.8
14.3
VS33UV
2.55
2.69
2.83
VS5UV
4.1
4.3
4.5
12V(VCC)UV
Leakage Current(FPO)
ILKG1
Low Level Output Voltage(FPO)
VOLI
8.8
9.3
9.8
VFPO = 5V
-
-
5
Isink=10mA
-
-
0.3
Isink=30mA
-
-
0.7
Min.
Typ.
Max.
Unit
V
V
uA
V
PGI and PGO
Characteristic
Symbol
Test Condition
Unit
Input Threshold Voltage(PGI)
VPGI
1.16
1.20
1.24
V
Leakage Current(PGO)
ILKG2
VPGO = 5V
-
-
5
uA
Low Level Output Voltage(PGO)
VOL2
Isink=10mA
-
-
0.4
V
Min.
Typ.
Max.
Unit
-
150
-
uA
PSON Control
Characteristic
Symbol
Test Condition
VPSON = 0V
Input Pull-up Current
High-Level Input Voltage
2.4
-
-
V
Low-Level Input Voltage
-
-
1.2
V
Min.
Typ.
Max.
Unit
-
-
1
mA
Total Device
Characteristic
Symbol
Supply Current
ICC
Test Condition
VPSON = 5V
Timing Characteristics
(VCC=5V, Ta=25°C, unless otherwise specified)
Characteristic
Symbol
Test Condition
Note 4
PGO Delay Time(PGI to PGO)
tb1
tb2
td1
Internal UVP Delay Time
td2
FPO goes low and
every time PGI > 1.20
PSON Off to FPO Delay Time
td3
Debounce Time(PSON)
Noise Debounce Time
Min.
Typ.
Max.
Unit
25
38
51
ms
50
73
100
us
200
300
410
ms
51
75
102
ms
tb1+1.6
tb1+2.3
tb1+3.2
ms
Note
1. VCC slew rate must be less than 14V/ms.
2. All voltages are measured with respect to the ground pin, unless otherwise specified.
3.The Absolute Maximum Ratings indicate the limits that if exceed, damage to the device may occur. Recommended Operating
Conditions indicate conditions in which the device is functional, but do not guarantee specific performance limits.
4. This parameter, although guaranteed over the Timing Characteristics, is not 100% tested in production.
5
FAN7680
6
6
5
5
4
4
PGO (V)
FPO (V)
Typical Characteristics
3
3
2
2
1
1
0
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
1.14
1.16
1.18
1.20
PSON (V)
6
6
5
5
4
4
3
3
2
2
1
1
0
0
2.83
2.79
2.75
2.71
2.67
2.63
2.59
2.55
3.90 3.94 3.98 4.02 4.06 4.10 4.14 4.18 4.22 4.26 4.30
VS33 (V)
VS33 (V)
Figure 3. +3.3V UVP Voltage
Figure 4. +3.3V OVP Voltage
6
6
5
5
4
4
FPO (V)
FPO (V)
1.24
Figure 2. PGI Threshold Voltage
FPO (V)
FPO (V)
Figure 1. PSON Threshold Voltage
3
3
2
2
1
1
0
0
4.50
4.45
4.40
4.36
4.31
4.26
4.21
VS5 (V)
Figure 5. +5V UVP Voltage
6
1.22
PGI (V)
4.16
4.12
5.80
5.88
5.96
6.04
6.12
6.20
6.28
VS5 (V)
Figure 6. +5V OVP Voltage
6.36
FAN7680
6
6
5
5
4
4
FPO (V)
FPO (V)
Typical Characteristics
3
3
2
2
1
1
0
0
9.80
9.60
9.40
9.20
Vcc (V)
Figure 7. +12V UVP Voltage
9.00
8.80
13.30
13.50
13.70
13.90
14.10
14.30
14.50
Vcc (V)
Figure 8. +12V OVP Voltage
7
FAN7680
Timing Chart
1) AC Input ON/OFF - Normal State
VCC
AC Input
Enable
POR
PSON
FPO
tb1
PGI
AC Input
Disable
UVP
Threshold
OUT
tb2+td1
PGO
2) PSON ON/OFF - Normal State
PSON
FPO
td3
tb1
PGI
UVP
Threshold
OUT
tb1+tb2
PGO
- Vcc : Supply Voltage
- POR : Power On Reset
- PSON : Power Supply On/Off
- FPO : Fault Protection Output
- PGI : Power Good Input
- OUT : Output Voltages
- PGO : Power Goood Output
8
tb2+td1
FAN7680
3) Under Voltage at Normal State
PSON
Latch
FPO
tb1
tb2
PGI
UVP
Threshold
UVP
Threshold
OUT
tb2+td1
PGO
4) Under Voltage at AC Input ON
VCC
AC Input
Enable
POR
Latch
PSON
FPO
PGI
tb1
tb2+td2
PGI
Threshold
UVP
Threshold
OUT
PGO
tb2+td1
9
FAN7680
5) Under Voltage at PSON ON/OFF
Latch
PSON
FPO
td3
tb1
tb2+td2
PGI
PGI
Threshold
UVP
Threshold
OUT
tb1+tb2
tb2+td1
PGO
6) Over Voltage at PSON ON/OFF
PSON
FPO
Latch
tb2
PGI
OUT
PGO
10
tb1
UVP
Threshold
OVP
Threshold
tb2+td1
FAN7680
Application Information
Power Good(PGO) and Power Good Delay
A PC power supply is commonly designed to provide the motherboard with a power good signal, which is defined by the computer manufactures. If the +3.3V, +5V, and +12V outputs are above the undervoltage threshold limit, the PC power supply
makes the power good signal high after some delay. At this time the power supply should be able to provide enough power to
assure continuous operation within the specification. Conversely, when one of the +3.3V, +5V, or +12V outputs falls below the
undervoltage threshold or rise above the overvoltage threshold, or when main power has been turned off for a sufficiently long
time so that power supply operation is no longer assured, a PGO signal will be a low state.
The AC input, power good(PGO), remote on/off(PSON), and +3.3V/+5V/+12V supply rails are shown in figure 1.
T1
T5
VAC
PSON
+12VDC
+5VDC
+3.3VDC
PGO
95%
10%
Figure 1. Timing Diagram
T3
T2
T4
T5
Although there is no requirement for specific timing parameters, the following signal timings are recommended :
-T1(Power On Time) : T1 < 500ms
-T2(Rise Time) : 0.1ms ≤ T2 ≤ 20ms
-T3(PGO Delay) : 100ms < T3
很抱歉,暂时无法提供与“FAN7680N”相匹配的价格&库存,您可以联系我们找货
免费人工找货