Transcript PowerPoint 프레젠테이션

Fairchild Power Switch
Sep, 2004
Power Conversion
The Value Proposition of PoE
Before
Each end device needs
it’s own power supply.
External AC/DC Adaptor
After
Each end device gets
it’s own power from the network.
Built in DC/DC Converter
The Motivation for Power over Ethernet
Almost all appliances require both data connectivity and a power supply. In a familiar example,
telephones are powered from the telephone exchange through the same twisted pair that carries
the voice. Now we can do the same thing with Ethernet devices.
So why bother? Here are some reasons:
• Only one set of wires to bring to your appliance - simplifies installation and saves space.
• There is no need to pay for an expensive electrician, or delay your installation to meet the
electrician's schedule - saves time and money.
• The appliance can be easily moved, to wherever you can lay a LAN cable - minimal disruption
to the workplace.
• Safer - no mains voltages anywhere.
• A UPS can guarantee power to the appliance even during mains power failure.
• As well as the data transfer to and from the appliance, you can use SNMP network
management infrastructure to monitor and control the appliances.
• Appliances can be shut down or reset remotely - no need for a reset button or power switch.
• In wireless LAN systems it simplifies the RF survey task, as the access point can easily be
moved and wired in.
Some Possible Uses of the Technology
Already manufacturers have products on the market. Many of these are described in the
Products section of the www.PowerOverEthernet.com website. There is no shortage of the
Power Sourcing Equipment Midspan Hubs, so you can start playing with the technology now.
The big market players are using it for these applications:
• VoIP (Voice over Internet Protocol) telephones.
• IEEE802.11 Wireless LAN Access Points.
• Bluetooth Access Points.
• Web cameras.
But Power Over Ethernet will enable many more appliances. Here's a list - but you can imagine
others!
• Smart signs/web signs.
• Vending machines.
• Gaming machines.
• Audio and video juke boxes.
• Retail point of information systems.
• EPOS systems.
• Building access control systems.
• Time and attendance systems.
• Battery chargers for mobile phones and PDAs.
• Electronic musical instruments.
Power-over-Ethernet(PoE) LAN switches
The user would merely have to plug the devices into a traditional Category-5,
Ethernet-cable wall socket.
How PoE is done
The power for Power-over-Ethernet devices can be supplied through the spare
wires of a typical CAT-5 cable. This is supported by the standard.
Cat5 cable
RG-45
RG-45
RG-45
RG-45
Switch End
DTE end
Switch End
DTE end
Normal legacy network
Power Supplied over the Spare Pins
FS6X1220R

Description
• The FS6X1220R is a high voltage power
switching regulator that combines the
required converter functions with allowing a
simple power system solution for DC-DC
converters

Features
• Optimized for Off-line type DC to DC
Converter
• High switching frequency for good efficiency
(300KHz)
• Line UVLO monitoring and Sleep on/off
• Various protection functions (OVP, OLP, TSD)
• Auto restart mode
• TO-220F-5L / D2-PAK-5L
• Over 80% Efficiency
 Low Rds(on) QFET minimizes conduction
losses
 Low capacitance QFET cuts switching
losses
Start-up
• During start up, the power is supplied to Vcc pin from DC link through startup
resistor.
• When Vcc reaches the UVLO upper threshold, the power is supplied from
auxiliary transformer winding.
VDC
Vds
Rstart
Vc
Vcc
Vcc
3
15V
Vref
9V/15V
Vcc good
Internal
Bias
9V
Feedback for off-line DC/DC converters
Vcc
Idelay
VFB
Vref
IFB
4
FB
28R
OSC
PWM
Vx
R
S
Q
R
Q
Gate
driver
LEB
Vx
2
GND
 Optimized Feedback for off-line DC/DC converters
 Current Mode PWM IC
Features: Over Load Protection
Vck
Secondary Side
5uA
Vo
1mA
FPSTM
OSC.
FB
V
Shutdown
7.5V
2.8R
Cfb
S
Vfb*
R
R
Q
3V
Voffset
LEB
0
7.5V
Reset
Thermal
Shutdown
t1
R
S
Q
t
t2
Shutdown
•Time Constant :
5uA = Cfb * 4.5V / t2
• Consider the load current increasing significantly
• FPSTM increases its duty cycle within the limits of its pulse-by-pulse current limit
• Output voltage falls and the feedback voltage rises
• If just a momentary surge then the output will rise after the surge and the feedback voltage will resume
its steady state
• However, if output is shorted to ground, then feedback voltage continues to rise
• At 3V, feedback voltage is pulled up with a small internal 5µA current allowing for adjusting the delay
as shown above
• When feedback voltage crosses the over-load shutdown (VSD) threshold, the FPS stops switching
• With FPSTM not switching, no bias current is supplied and supply Vcc will fall
• When the Vcc voltage reaches its “Under Voltage Lock Out” threshold, the FPSTM is automatically
restarted
• The cycle will repeat until the fault condition is removed.
Over Voltage Protection
FS6X1220RT
5uA
1mA
Vck
OSC.
2.5R
S
Vfb*
Q
R
R
Reset
R
Shutdown
Q
S
7.5V
Vcc
Vcc
Thermal
Shutdown
Vovp
 Protection for over voltage
 Auto restart mode
Auto Restart
Vds
Power
on
Fault
occurs
Fault
removed
Vcc
3
9V/15V
Vcc good
Vref
Vcc
Internal
Bias
OLP
9V
OVP
Line
UVLO
15V
S
Q
R
Q
Stop
switching
OTP
Icc
10mA
60uA
t
Normal
operation

Fault
situation
Normal
operation
Auto-restart : protection latch is automatically reset when Vcc < 9V
Sleep mode and Line UVLO
Vin
Vcc
3
Vcc good
9V/15V
R1
VSL
(1.8v)
Sleep
ON OFF
Enable
Vref
Line
Sense
5
R2
VLU
(2.5V)
Line UVLO
Internal
Bias
 Line UVLO mode (VLS<2.5V): operating current = 10mA
 Sleep mode (VLS<1.8V): operating current = 300uA
 Startup current : 60 uA
Measured Efficiency
Input = 36V
Io
Vo
Po
Pin
Efficiency
Input =60V
Io
Vo
Pin
Po
Efficiency
1A
3.362V
3.36W
4.14W
81.13%
1A
3.378V
3.38W
4.80W
70.33%
2A
3.357V
6.71W
7.64W
87.91%
2A
3.373V
6.75W
8.57W
78.73%
3A
3.351V
10.05W
11.31W
88.92%
3A
3.365V
10.10W
12.22W
82.62%
4A
3.345V
13.38W
15.02W
89.08%
4A
3.357V
13.43W
16.01W
83.86%
5A
3.338V
16.69W
18.66W
89.45%
5A
3.346V
16.73W
19.87W
84.21%
6A
3.362V
20.17W
22.78W
88.55%
6A
3.334V
20.00W
23.84W
83.91%
Input =48V
Io
Vo
Pin
Po
Input =72V
Efficiency
Io
Vo
Pin
Po
Efficiency
1A
3.374V
3.37W
4.58W
73.72%
1A
3.381V
3.38W
5.09W
66.41%
2A
3.369V
6.74W
8.20W
82.20%
2A
3.375V
6.75W
8.97W
75.28%
3A
3.363V
10.09W
11.89W
84.88%
3A
3.368V
10.10W
12.67W
79.73%
4A
3.355V
13.42W
15.67W
85.67%
4A
3.359V
13.44W
16.45W
81.70%
5A
3.345V
16.73W
19.53W
85.63%
5A
3.346V
16.73W
20.31W
82.37%
6A
3.334V
20.00W
23.57W
84.87%
6A
3.335V
20.01W
24.25W
82.52%
Measured Efficiency
FS6X1220R Efficiency
95.00%
90.00%
85.00%
Efficiency
80.00%
75.00%
70.00%
65.00%
Input
Input
Input
Input
60.00%
55.00%
=
=
=
=
50.00%
1A
2A
3A
4A
Output Current
5A
6A
36V
48V
60V
72V