SYSTEM GENERAL SG6108 Product Specification
Product Specification
Power Supply Supervisor + PWM SG6108
© System General Corp. - 1 - www.sg.com.tw • www.fairchildsemi.com
Version 1.0.1 (IAO33.0048.B0) September 26, 2007
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Main Transfor mer
5Vsb
Pok
Pson
Vdd
12V
5V
-5V
-12V
3.3V
5V
12V
12V
-12V
UVAC IS12
Vcc
PG
IS5
IS33
V33
V5
V12
VS12B
Pson
OP1
NVP
RI
GND
IN
COMP
SS
OP2
OPP
SG6108
FEATURES
PC half-bridge (or 494) power supply supervisor +
PWM
Highly Integrated and Few external components
required
Over voltage protection 3.3V/5V/12V (two 12V)
Under voltage protection 3.3V/5V/12V (two 12V)
Under voltage protection for –12V and/or –5V
Over current protection 3.3V/5V/12V (two 12V)
Over power protection
Short circuit protection
Power-down warning circuitry
Power good circuitry
Delay time for PSON and PG signals
Remote ON/OFF function
On-Chip oscillator and Error amplifier
Latching PWM for cycle-by-cycle switching
Soft-start
Maximum 48% duty cycle
APPLICATIONS
Switching mode power supplies for computers such
as ATX, NLX, and SFX (micro-ATX).
DESCRIPTION
The SG6108 controller is designed for desktop PC
switching mode power supplies. It provides everything
necessary to monitor and control the output of the power
supply. Remote ON/OFF control, power good circuitry,
over-voltage protection, over-power protection, and
over-current protection are all included. The SG6108
directly senses all the output rails for over voltage
conditions without requiring external dividers. An
innovative AC-signal sampling circuit provides an
adequate power-down warning signal for PG. A built-in
timer generates accurate timing for the control circuit.
Cycle-by-cycle PWM switching protects the power
transformer from saturation and ensures a rapid response
for short-circuit protection. This greatly reduces the stress
on the power transistors. The SG6108 utilizes a minimum
number of external components while including all the
functions needed for push-pull and/or half-bridge
topologies. This decreases production costs and PCB
space while increasing the power supply’s MTBF.
TYPICAL APPLICATION
查询SG6108DZ供应商
Product Specification
Power Supply Supervisor + PWM SG6108
© System General Corp. - 2 - www.sg.com.tw • www.fairchildsemi.com
Version 1.0.1 (IAO33.0048.B0) September 26, 2007
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20
19
18
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16
15
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12
11
PSON
V33
V5
OPP
UVAC
NVP
VS12
OP2
OP1
PG
VS12B
IS12
IS5
IS33
GND
COMP
IN
SS
RI
VCC
MARKING DIAGRAMS P I N CONFIGURATION
ORDERING INFORMATION
Part Number Pb-Free Package
SG6108DZ
20-Pin DIP
T : D = DIP
P : Z = Lead Free
Null=regular package
XXXXXXXX: Wafer Lot
Y: Year; WW: Week
V: Assembly Location
20
1
SG6
108
TP
XXXXXXXXYWWV
Product Specification
Power Supply Supervisor + PWM SG6108
© System General Corp. - 3 - www.sg.com.tw • www.fairchildsemi.com
Version 1.0.1 (IAO33.0048.B0) September 26, 2007
PIN DESCRIPTIONS
Name Pin Type Function
PSON 1 Logic Input
Remote On/Off logic input for the CPU or the controller. Turns the PWM output on/off following a 45
msec / 16 msec delay.
PSON = 0 means that the main SMPS is operational.
PSON =1 means that the main SMPS is off and the latch is reset.
V33 2 Analog Input 3.3V over-voltage/under-voltage control sense input.
V5 3 Analog Input 5V over-voltage/under-voltage control sense input.
OPP 4 Analog Input
Over-power sense input. This pin is connected to the driver transformer or the output of the current
transformer. When not in use, this pin should be grounded.
UVAC 5 Analog Input AC fail-detection. This detects main AC voltage under-voltage and/or failure.
NVP 6 Analog Input The protection input for negative outputs, such as –12V and/or –5V. Trip voltage = 2.1V.
VS12 7 Analog Input 12V over-voltage/under-voltage control sense input.
OP2/OP1 8/9 Analog Output
The totem-pole output drivers of a push-pull PWM. The outputs are enabled (low) only when the
NAND gate inputs are high. The maximum duty cycle on an output (OP1 or OP2) is 48%.
PG 10 Logic Output
Power Good logic output, 0 or 1 (open-collector). PG = 1 means that the power is good for operation.
The PG delay is 300 msec.
VS12B 11 Analog Input Second 12V over-voltage/under-voltage control sense input.
IS12 12 Analog Input 12V over current protection sense input. The sink current = 8 x IRI
IS5 13 Analog Input 5V over current protection sense input. The sink current = 8 x IRI
IS33 14 Analog Input 3.3V over current protection sense input. The sink current = 8 x IRI
GND 15 Supply Ground.
COMP 16 Analog Output The error amplifier output and the input of the PWM comparator.
IN 17 Analog Input
The negative input of the error amplifier. The positive input of the error amplifier is a 2.5V reference
voltage.
SS 18 Analog Input
Soft-start. This can be set through the external capacitor. The current source output at this pin is 8uA
and the voltage is clamped at 2.5V.
RI 19
Program.
Analog Input
This is connected to the external resistor to provide a reference setting. It determines the PWM
frequency, and also the OCP current setting. Setting RI = 75kΩ will result in a PWM frequency of
65kHz. Do not attach a capacitor to this pin. For OCP current settings please refer to the Over Current
Protection section on page 13.
VCC 20 Supply Supply voltage. 4.5V ~ 5.5V. It is connected to the 5V-standby.
Product Specification
Power Supply Supervisor + PWM SG6108
© System General Corp. - 4 - www.sg.com.tw • www.fairchildsemi.com
Version 1.0.1 (IAO33.0048.B0) September 26, 2007
BLOCK DIAGRAM
Product Specification
Power Supply Supervisor + PWM SG6108
© System General Corp. - 5 - www.sg.com.tw • www.fairchildsemi.com
Version 1.0.1 (IAO33.0048.B0) September 26, 2007
TIMING DIAGRAM
VCC
PSON
3.3V,5V,12V
t
pson(on)
t
uvp
NVP
t
pson(off)
t
nvp
SS(on/off)
t
psoff
PG
t
PG
VCC
PSON
Voltage < V
UVAC
UVAC
t
OPP
OPP
SS(on/off)
PG
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