T EC H NO LO GY
`
`DESIGN
`NOTES
`
`PCI Express Power and Mini Card Solutions – Design Note 346
`Mitchell Lee and Vladimir Ostrerov
`
`Introduction
`PCI Express is the third generation of PCI (Peripheral
`Component Interconnect) technology used to connect
`I/O perhipheral devices in computer systems. It is
`intended as a general purpose I/O device interconnect
`that meets the needs of a wide variety of computing
`platforms such as desktop, mobile, server and commu-
`nications. It also specifi es the electrical and mechanical
`attributes of the backplane, connectors and removable
`cards in these systems.
`Power Requirements
`Each add-in card connector requires two power rails:
`12V and 3.3V, along with a third, optional 3.3V auxil-
`iary rail. If the designer elects to provide the auxiliary
`3.3V rail in his system or if the platform supports the
`WAKE# signal, the 3.3VAUX rail must be supplied to all
`connectors.
`In PCI Express, as in PCI, the Hot Swap™ controller is
`resident on the platform side of the system, delivering
`power to the connectors only after a card is inserted.
`This way, empty and otherwise unused connectors
`are safely unpowered, reducing the risk of inadvertent
`power supply faults, connector damage and simplifying
`power-up when a card is inserted into the connector.
`Table 1 shows the PCI Express power supply rail
`specifi cations per connector, based on the number of
`connectors in the system.
`Table 1. Summary of PCI Express Power Supply
`Requirements
`
`×1
`CONNECTOR
`
`×4/×8
`CONNECTOR
`
`×16
`CONNECTOR
`
`0.5A
`300μF
`
`3A
`1000μF
`
`0.375A
`150μF
`
`2.1A
`1000μF
`
`4.4A (Up to 5.5A)
`2000μF
`
`3A
`1000μF
`
`0.375A
`150μF
`
`3A
`1000μF
`
`0.375A
`150μF
`
`POWER RAIL
`12V
`Supply Current
`Capacitive Load
`3.3V
`Supply Current
`Capacitive Load
`3.3VAUX
`Supply Current
`Capacitive Load
`
`09/04/346_conv
`
`PCI Express Mini Card also provides two power sources:
`3.3V and 1.5V. The auxiliary voltage (3.3VAUX) is sourced
`over the same pins as the primary 3.3V supply and is
`available during the standby/suspend state to support
`wake-event processing on the Mini Card. Table 2 sum-
`marizes PCI Express Mini Card power specifi cations.
`There is no requirement for supply sequencing in either
`PCI Express or PCI Express Mini Card; the supplies may
`come up or go down in any order.
`
`PRIMARY POWER AUXILIARY POWER
`1A
` —
`
`Table 2. Summary of PCI Express Mini Card Supply
`Requirements
`POWER RAIL
`3.3V
`Peak Supply Current
`1.5V
`Peak Supply Current
`3.3VAUX
`Peak Supply Current
`Note: All values are maximums.
`
`0.5A
`
`0.33A
`
`—
`
`0.25A
`
`Circuit Solutions
`Figure 1 shows a circuit for a ×16 connector PCI Express
`system, implemented with an LTC®1647 dual Hot Swap
`controller. As shown, port power is gated by a control
`signal applied through 4.7k resistors to the ON pins.
`The FAULT outputs are cross-coupled with the ON pins
`such that if an overcurrent fault occurs on either sup-
`ply, the unaffected rail also shuts down. Shutdown is
`reset by toggling the control signal into the off state
`for at least 100μs.
`The supply rails slew at less than 1.5V/ms, well under
`any of the PCI Express limits. Thus the only alteration
`necessary to scale the design for ×1, ×4 and ×8 connec-
`tor systems is to replace the 12V supply sense resistor
`with 70mΩ (×1) or 15mΩ (×4/×8) as appropriate.
`
`L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks
`and Hot Swap and ThinSOT are trademarks of Linear Technology Corporation. All
`other trademarks are the property of their respective owners.
`Exhibit
`2102
`
`Netlist Ex 2102
`Samsung v Netlist
`IPR2022-00996
`
`

`

`VIN
`12V
`
`VIN
`3.3V
`
`100nF
`
`100nF
`
`7mΩ
`500mW
`
`IRF7413
`
`10μF
`
`12mΩ
`500mW
`
`IRF7413
`
`10μF
`
`10Ω
`1k
`
`10Ω
`
`1k
`
`10nF
`
`VOUT
`12V
`5.5A
`
`VOUT
`3.3V
`3A
`
`15
`S1
`
`13
`G1
`
`16
`VCC2
`
`14 12
`S2 G2
`
`10nF
`
`LTC1647-3CGN
`
`GND
`8
`
`DN346 F01
`
`1
`VCC1
`FAULT2
`ON1
`ON2
`
`FAULT1
`
`5 2
`
`4 3
`
`4.7k
`
`4.7k
`
`OFF/RESET ON
`
`Figure 1. PCI Express Port Power for ×16 Connector
`Satisfi es dV/dt Specifi cations, Soft-Starts Full Load
`Capacitance and Guards Against Short Circuits and
`Overloads
`
`Figure 2 shows a current limited circuit breaker for the
`optional 3.3VAUX rail, using the LTC4210 Hot Swap
`controller in a 6-lead ThinSOT™ package. With the
`ON pin (3) hard-wired to 3.3V, the LTC4210 operates
`autonomously, featuring a timed current limit to protect
`against overloads. Should the circuit breaker trip in the
`presence of a sustained fault, the LTC4210 automatically
`restarts after a time delay, requiring no intervention on
`the part of the PCI Express port manager.
`PCI Express Mini Card
`Mini Card circuit requirements differ from PCI Express
`in several ways, but most importantly the Hot Swap
`controller resides on the card itself. In this confi guration,
`it is important for the Hot Swap controller to monitor
`the incoming power and switch on only when those
`voltages are fully established.
`
`Figure 2. Optional 3.3VAUX Port Power with Self-
`Reseting, Current-Limited Circuit Breaker Operates
`Autonomously or Under Logic Control
`
`Figure 3 shows a Mini Card Hot Swap control circuit
`implemented with an LTC1645, with undervoltage and
`overcurrent monitoring on both the 3.3V and 1.5V sup-
`plies. A fault on either supply rail causes both channels
`to shut down simultaneously. An open-drain signal
`at the ON pin permits optional logic control over the
`LTC1645. Similar to the LTC1647, pulsing ON low resets
`the LTC1645 after a fault.
`For 3.3VAUX, simply add the circuit of Figure 2 in parallel
`at the 3.3V output. Note that with both circuits enabled
`and providing power to the 3.3V output, the available
`current is greater than 1.5A.
`A complete defi nition of the PCI Express power delivery
`requirements is found in the PCI Express Card Electro-
`mechanical Specifi cation and PCI Express Mini Card
`Electromechanical Specifi cation. Further information
`is available at www.pcisig.com.
`
`VOUT
`3.3V
`1A
`
`VOUT
`1.5V
`0.5A
`
`CLOAD
`
`CLOAD
`
`RESET
`
`DN346 F03
`
`10V
`
`100nF
`
`10k
`
`124Ω
`
`1370Ω
`
`VIN
`3.3V
`
`VIN
`1.5V
`
`40mΩ Si1400DL
`
`10Ω
`
`82mΩ
`
`Si1400DL
`
`10Ω
`
`6 4 5
`
`3
`2
`S2 G2
`FB
`
`FAULT
`
`RESET
`
`330nF
`
`4990Ω
`
`1820Ω
`
`124Ω
`
`1370Ω
`
`14
`VCC1
`ON
`COMPOUT
`
`COMP+
`
`10
`9
`
`8
`
`13
`S1
`
`12
`G1
`
`1
`VCC2
`
`LTC1645CS
`
`GND
`7
`
`TIMER
`11
`
`Figure 3. PCI Express Mini Card Hot Swap Circuit Resides on Mini Card
`
`Data Sheet Download
`www.linear.com
`
`For applications help,
`call (408) 432-1900
`
`Linear Technology Corporation
`1630 McCarthy Blvd., Milpitas, CA 95035-7417
`(408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com
`
`dn346f_conv LT/TP 0904 435K • PRINTED IN THE USA
`
`Li LII1tAJ≥
`
`TECHNOLOGY
`© LINEAR TECHNOLOGY CORPORATION 2004
`
`100mΩ
`
`Si1400DL
`
`VIN
`3.3V
`
`100nF
`
`AUX OUTPUT
`3.3V
`375mA
`
`10μF
`
`(OPTIONAL
`LOGIC
`CONTROL
`INPUT)
`
`OFF ON
`
`3
`
`100Ω
`100Ω
`
`4
`
`10nF
`
`5
`
`6
`S
`G
`VCC
`LTC4210-1CS6
`
`ON
`GND
`2
`
`TIMER
`1
`
`220nF
`
`DN346 F02
`
`Netlist Ex 2102
`Samsung v Netlist
`IPR2022-00996
`
`