Mixed-Signal Products SLVA049 IMPORTANT NOTICE Texas Instrum

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TPS202x/3x TPS204x/5x Power Distribution
Mixed-Signal Products
SLVA049
IMPORTANT NOTICE Texas Instruments subsidiaries (TI) reserve right make changes their products discontinue product service without notice, advise customers obtain latest version relevant information verify, before placing orders, that information being relied current complete. products sold subject terms conditions sale supplied time order acknowledgement, including those pertaining warranty, patent infringement, limitation liability. warrants performance semiconductor products specifications applicable time sale accordance with TI's standard warranty. Testing other quality control techniques utilized extent deems necessary support this warranty. Specific testing parameters each device necessarily performed, except those mandated government requirements. CERTAIN APPLICATIONS USING SEMICONDUCTOR PRODUCTS INVOLVE POTENTIAL RISKS DEATH, PERSONAL INJURY, SEVERE PROPERTY ENVIRONMENTAL DAMAGE ("CRITICAL APPLICATIONS"). SEMICONDUCTOR PRODUCTS DESIGNED, AUTHORIZED, WARRANTED SUITABLE LIFE-SUPPORT DEVICES SYSTEMS OTHER CRITICAL APPLICATIONS. INCLUSION PRODUCTS SUCH APPLICATIONS UNDERSTOOD FULLY CUSTOMER'S RISK. order minimize risks associated with customer's applications, adequate design operating safeguards must provided customer minimize inherent procedural hazards. assumes liability applications assistance customer product design. does warrant represent that license, either express implied, granted under patent right, copyright, mask work right, other intellectual property right covering relating combination, machine, process which such semiconductor products services might used. TI's publication information regarding third party's products services does constitute TI's approval, warranty endorsement thereof.
Copyright 1998, Texas Instruments Incorporated
Contents
Introduction TPS202x/3x TPS204x/5x Power Distribution Switches Definitions Power Distribution Power Distribution Self-Powered Hubs (Including Hosts) Self-Powered Port Protection Topologies Ganged Port Protection Individual Port Protection Output Capacitance Ferrite Beads Transient Response Self/Bus Powered Hybrid Summary
List Figures
Maximum Voltage Drops Droops Power Distribution System Self Powered Simplified Ganged Port Protection Topology TPS2024 Ganged Port Protection Topology Four-Port Ganged Using Tantalum Electrolytic Four-Port Ganged Using Aluminum Capacitors Simplified Individual Port Protection TPS2044 Individual Port Protection Application TPS2044 Four Port Using Tantalum Output Capacitors TPS2044 Four Port Using Aluminum Electrolytic Output Capacitors Filter Self/Bus Powered Hybrid
List Tables
Texas Instruments Power Distribution Switches Voltage Droop Results Ganged Port Protected Self-Powered Topology Voltage Droop Results Individual Port Protected Self-Powered Output Capacitors Used Testing Voltage Droop Ferrite Beads Used Testing Voltage Droop
TPS202x/3x TPS204x/5x Power Distribution
SLVA049
TPS202x/3x TPS204x/5x Power Distribution
ABSTRACT specification, revision 1.1, defines power distribution requirements self-powered hubs (including hosts), bus-powered hubs, functions. This application report demonstrates Texas Instruments power management products meet exceed voltage regulation, voltage droop, requirements power distribution system.
Introduction
Universal Serial (USB) interface 12-Mb/s 1.5-Mb/s, multiplexed serial medium bandwidth peripherals (e.g., keyboards, printers, scanners, mice). four-wire interface provides dynamic attach-detach (hot plug-unplug) peripherals. lines provided differential data lines provided power distribution. data 3.3-V level signal, power distributed allow voltage drops cases where power distributed through more than hub. Each function must provide regulated from input from internal power supply. specification defines following five classes devices, each differentiated power consumption requirements: Bus-powered hubs Self-powered hubs power, bus-powered functions High power, bus-powered functions Self-powered functions Self-powered bus-powered hubs distribute data power downstream functions. This application report describes power distribution solutions both types hubs functions.
TPS202x/3x TPS204x/5x Power Distribution Switches
TPS202x/3x TPS204x/5x Power Distribution Switches
Texas Instruments offers variety power switch devices applications: TPS202x, TPS203x, TPS204x, TPS205x. devices high-side switches with built-in overcurrent protection that includes open-drain, active-low overcurrent flag output overcurrent reporting. switches provide power switching maintenance-free fault protection; they controlled 3.3-V logic level compatible enables. added flexibility interfacing with controllers, devices available active-low active-high enables. TPS202x (active-low) TPS203x (active-high) families devices 50-m high-side N-channel MOSFET switches that offered different current limit levels. TPS202x/3x families ideal ganged-port protected power distribution system topologies. TPS2041/2/4 TPS2051/2/4 series devices 135-m high-side N-channel MOSFET switches rated fixed continuous current with typical current limit TPS204X series differs number power switches available each packaged device: TPS2041 (Single), TPS2042 (Dual), TPS2044 (Quad). TPS2041 series ideal individual port protection one-port (TPS2041), two-port (TPS2042), four-port (TPS2044) topologies. TPS204X devices enabled with active-low logic enable. TPS2042 TPS2044 devices incorporate dual thermal trip allow fully independent operation dual power distribution switches. over-current short-circuit conditions, junction temperature rises. Once temperature rises internal trip point, thermal sense circuitry determines which switch over-current condition turns that power switch off, isolating fault without interrupting operation adjacent power switch. second thermal trip point higher temperature point that turns both switches. Active-high versions also available: TPS2051, TPS2052, TPS2054 single, dual, quad power switches. Table lists characteristics TPS20xx family devices. Table Texas Instruments Power Distribution Switches
PART NUMBER TPS2041 TPS2051 TPS2042 TPS2052 TPS2044 TPS2054 TPS2022 TPS2032 TPS2023 TPS2033 TPS2024 TPS2034 SWITCHES Single Single Dual Dual Quad Quad Single Single Single Single Single Single ENABLE LOGIC Active-low Active-high Active-low Active-high Active-low Active-high Active-low Active-high Active-low Active-high Active-low Active-high RESISTANCE CONTINUOUS CURRENT CURENT LIMIT
Product Preview, release 1Q99
SLVA049
Definitions
Definitions
Bus-powered Bus-powered hubs (BPH) obtain power from upstream ports often contain nonremovable function. typical application keyboard. total current drawn controller current, nonremovable function, downstream port greater than unit loads. Each port must distribute unit load. Current limit specification requires SPHs limit current downstream ports report over-current conditions controller. Downstream port port that electrically further from host generates downstream data traffic from hub. Dynamic attach detach attach remove devices while host operation (hot-plug, unplug event). High-power, bus-powered function power these devices comes from upstream port. current draw unit load before configuration unit loads after configuration. Host host computer system where host controller installed. Inrush current current surge into uncharged downstream input capacitors. Low-power, bus-powered function power these devices comes from upstream port. current draw less than unit load. Power Switching specification requires BPHs power switch downstream ports limit aggregate current draw controller, function, ports less than before enumeration. Self-powered function draw unit load from upstream port. remainder power provided from local power supply. Self-powered Self-powered hubs (SPH) have local power supply that power nonremovable functions downstream ports. Typical self-powered hubs PCs, monitors, printers, stand alone hubs. required have current limit report overcurrent conditions. must able supply unit loads external downstream ports even when suspended state. battery-powered configure unit load unit loads output current port. Unit load unit load Upstream port port device that electrically closer host generates upstream data traffic from hub. Universal Serial Voltage droop momentary drop voltage under transient load conditions. Voltage regulation difference voltage levels under continuous load no-load conditions.
TPS202x/3x TPS204x/5x Power Distribution
Power Distribution
Power Distribution
power distribution requirements designed that 4.35 minimum voltage supplied downstream functions. power distribution system supplied power from host self-powered distributed downstream. Resistive voltage drops associated with each connection, trace, cable, other component power distribution system. specification dictates minimum voltages downstream ports self-powered hubs, bus-powered hubs, downstream function when operating continuous load current states transient states during hot-plug events (see Figure minimum voltage self-powered hubs board side connection 4.75 bus-powered hub. Bus-powered hubs allowed 100-mV voltage drop leaving 250-mV voltage drop cable. During hot-plug connections, self-powered voltage allowed drop 4.42 4.07 bus-powered hub. Downstream functions should have voltage 4.35 hubs functions must able provide configuration information with minimum voltage connector upstream cables. specification also dictates that downstream devices (self-powered hubs, bus-powered hubs, bus-powered functions, self-powered functions) only sink (draw) current from source voltage. downstream devices must able enter into suspend state reduce current consumption. Suspend current function unit load allocation. devices initially default power limited suspend current. Devices configured high power enabled wake source draw Configured bus-powered hubs consume suspend current port nonremovable function total When determining suspend current, current through pull-up (1.5 pull-down resistors data lines must included. Figure summarizes voltage drops droops power distribution system.
Host Self-Powered 4.75 V/4.42 Minimum Bus-Powered V/4.07 Minimum Low-Power Bus-Power Function 4.35 Minimum
Figure Maximum Voltage Drops Droops Power Distribution System
SLVA049
Power Distribution Self-Powered Hubs (Including Hosts)
Power Distribution Self-Powered Hubs (Including Hosts)
Self-powered hubs (SPH) have local power supply that powers nonremovable functions downstream ports (Figure must supply 5.25 4.75 board side downstream connection under full-load no-load conditions required have current limit report overcurrent conditions software. Typical SPHs desktop PCs, monitors, printers, stand alone hubs. Power controller supplied local power supply upstream voltage loads advantage using power from upstream port that communication controller possible distinction between unconnected unpowered device made. Most controllers 3.3-V supply voltage, drop-out (LDO) voltage regulator needed regulate voltage number downstream ports supported self-powered hubs limited current local power supply support safety concerns. Each port must capable supplying unit loads must limit current when aggregate current drawn exceeds current limit should exceed continuous current level enough ensure that dynamic-attach events startup currents trip overcurrent protection. Figure shows typical SPH.
Upstream Data Port Controller TUSB2070 TUSB2040 TUSB2140 Downstream Data Port
Upstream Voltage Unit Load (max)
Regulator TPS7133 TPS7233
Regulator TPS7133 TPS7233
Nonremovable Function
On/Off
Current Limit TPS2041/51 TPS2042/52 TPS2044/54 TPS2022/23/24 TPS2032/33/34 Current Limit TPS2041/51 TPS2042/52 TPS2044/54 TPS2022/23/24 TPS2032/33/34
mA/Port
Downstream Voltage
On/Off Local Power Supply
mA/Port
Downstream Voltage
Figure Self Powered
TPS202x/3x TPS204x/5x Power Distribution
Self-Powered Port Protection Topologies
Self-Powered Port Protection Topologies
self-powered power distribution system designed with distinct topologies port protection: individual port protection ganged port protection. ganged port protection most economical least flexible topology fault isolation. ganged topology uses common current limit element more ports. ganged solution, more current flows through current limit device. resistance current limit device must low, exceed maximum voltage drop limit under full operating conditions. Fault isolation another limitation ganged solution. isolate fault ganged solution, power will interrupted adjacent port. This desirable some applications. individual port protection topology provides more robust configuration better end-user experience. individual port protection most flexible topology fault isolation power distribution system. individual port protection topology uses current limit elements each port, making isolating faults with minimal interruption adjacent ports possible. Ganged Port Protection When designing ganged topology low-resistance switch needed minimize voltage drop hub, because current downstream ports passes through current limit device (see Figure TPS202x power switches 50-m devices with current limit overcurrent response flag required self-powered hubs. current limit level devices been optimized ganged (TPS2022), three (TPS2023), four (TPS2024) port protection topologies. TPS2022 ideal two-port ganged solution; rated continuous current current limit Using ferrite beads with resistance less, two-port TPS2022 ganged port solution designed with 5.05 power supply with trace resistance higher current path. more trace resistance required, following equation calculate required source voltage tighter tolerance power supply.
4.75 number ports SWITCH
TRACE
RSWITCH
BEAD
manner similar two-port ganged protection solution, three- fourport ganged solution designed with TPS2023 TPS2024 devices, respectively. using above equation, right power supply calculated specific number ports, power switches, trace resistances. minimum voltage power supply full load over temperature range line regulation. output voltage must greater than 4.75 greater than 5.25 over legal load conditions upstream side connector.
SLVA049
Self-Powered Port Protection Topologies
R(TRACE) R(SWITCH) POWER SUPPLY I(T) I(1) 4.75
I(2) 4.75
I(3) 4.75
I(4) 4.75
Figure Simplified Ganged Port Protection Topology typical voltage droop two-, three- four-ganged port self-powered measured using different types (e.g. tantalum aluminum) values output capacitors with legal plug load Tantalum, aluminum electrolytic, ceramic capacitors were used 10-µF load capacitors investigate effect drooping. 10-µF ceramic capacitor resulted largest output voltage droop aluminum electrolytic gave smallest droop. Typical applications aluminum electrolytic capacitors less, voltage droop results will shown using 10-µF, 50-V capacitor. Voltage droop output varied with length cable equivalent series resistance load output capacitors. Figure shows TPS2024 ganged-port protection topology, Table lists voltage droop results ganged topology. Figure shows scope traces four port ganged using 33-µF tantalum capacitors, Figure shows same data using 100-µF aluminum electrolytic capacitors.
TPS202x/3x TPS204x/5x Power Distribution
Self-Powered Port Protection Topologies
TPS2024 Local Power Supply
Figure TPS2024 Ganged Port Protection Topology Table Voltage Droop Results Ganged Port Protected Self-Powered HubTopology
GANGED ALUMINUM
Figure Four Port Ganged Using Tantalum Capacitors
SLVA049
Self-Powered Port Protection Topologies
Figure Four-Port Ganged Using Aluminum Electrolytic Individual Port Protection Individual port protection advantages over ganged port protection power distribution system: individual port fault isolation, better voltage droop performance. ganged-port protection system, fault single port will interrupt service adjacent port. individual port protection system, fault isolated without interruption adjacent ports. Also, individual port protection provides better voltage droop performance resistive isolation power switches between ports, reducing charge sharing voltage droop during plug events. TPS2042 ideal device two-port requiring individual port protection solution; device rated continuous current switch with typical current limit TPS2042 also features independent thermal protection each switch, which disables switch overcurrent when over temperature condition occurs. two-port designed with trace resistance higher current path using 5.05-V power supply ferrite beads each port with resistances less. more trace resistance needed, tighter tolerance power supply should used.
4.75 number ports SWITCH
TRACE
SWITCH
BEAD
Using above equation power supply tolerance calculated three- four-port individually protected using TPS204x power switch devices. tolerance power supply must such that voltage will exceed 5.25 drop below 4.75 over conditions. same 10-µF/44- load used voltage droop test individually protected part. Figure shows simplified individual port protection schematic, Figure shows TPS2044 individual port protection application.
TPS202x/3x TPS204x/5x Power Distribution
Self-Powered Port Protection Topologies
R(TRACE) R(SWITCH) POWER SUPPLY I(T) I(1) 4.75
R(SWITCH)
I(2)
4.75
R(SWITCH) I(3)
4.75
R(SWITCH)
I(4)
4.75
Figure Simplified Individual Port Protection
TPS2044 GND1 GND2 OUT1 Local Power Supply OUT2 OUT3 OUT4
Figure TPS2044 Individual Port Protection Application
SLVA049
Self-Powered Port Protection Topologies
Table lists voltage droop individual port protected SPH. Figures show scope traces TPS2044 four-port using 33-µF tantalum 100-µF aluminum electrolytic output capacitors respectively. Table Voltage Droop Results Individual Port Protected Self-Powered
VOLTAGE DROOP SELF-POWERED GANGED ALUMINUM
Figure TPS2044 Four-Port Using Tantalum Output Capacitors
Figure TPS2044 Four-Port Using Aluminum Electrolytic Output Capacitors
TPS202x/3x TPS204x/5x Power Distribution
Self-Powered Port Protection Topologies
Output Capacitance minimum 120-µF equivalent-series-resistance (ESR) output capacitance required (i.e., four-port minimum port) bypass Vbus power lines. plug droop voltages should considered when choosing type capacitor. output capacitor affects Vbus voltage droop during plugging when maximum allowable load parallel with high-power bus-powered device, transitions from low-power mode high-power mode. cable length load capacitor determines peak inrush current maximum voltage droop. voltage applications, solid tantalum capacitors take less physical space same capacitance voltage rating than aluminum electrolytic capacitors, suffer from electrolyte out, which limits life expectancy aluminum electrolytic capacitors. meet specification, tantalum capacitors used four-, three-, two-port hubs, respectively. through-hole components preferred output capacitors, 100-µF aluminum electrolytic capacitors with less than used meet voltage droop requirement. Table summarizes data capacitors used test voltage droop. Table Output Capacitors Used Testing Voltage Droop
VALUE 0.90 0.70 0.70 0.46 CAPACITOR TYPE Tantalum Tantalum Tantalum Radial Aluminum Electrolytic PART NUMBER 293D336X0010D2T 293D476X0010D2T 293D686X0010D2T ECA-1AFQ101 MANUFACTURER Vishay Sprague Vishay Sprague Vishay Sprague Panasonic
Ferrite Beads Ferrite beads should used series with each Vbus, ground, data line reduce voltage droop during hot-plug events. Table lists ferrite beads used testing TPS20xx parts. ferrite beads that were used have resistance that minimal impact voltage regulation. Table Ferrite Beads Used Testing Voltage Droop
IMPEDANCE RESISTANCE FERRITE BEAD Ferrite bead surface mount Ferrite bead surface mount Ferrite bead surface mount PART NUMBER ACB-1812-5.0A SMB40 2743037447 MANUFACTURER Associated Components Technology Allied Components Fair-Rite
Transient Response hot-plug connection legal load 10-µF load enabled power switch device cause false overcurrent response when inrush current flows through device, charging down stream capacitor. filter must connected shown Figure reduce erroneous responses. Also, using ESR, large value, electrolytic capacitors output devices reduces pulse width eliminates false response minimizing current flow through device during hot-plug events, thereby providing lower impedance energy source.
SLVA049
Self-Powered Port Protection Topologies
pulse width erroneous response typically less than without output capacitor device when plugging 10-µF aluminum electrolytic capacitor. hot-plug load greater than 10-µF, pulse width will greater. Since response dependent many components power distribution, recommended test power distribution system with only pullup resistor determine necessary filter attenuate glitch. Once pulse width glitch known, filter resistance capacitance values calculated using equation below. most applications sufficient. precautionary note, pullup resistance should large cause false overcurrent response startup when controller voltage reaches final voltage well before voltage.
Tfilter Tstartup
Rfilter Cfilter (Rpullup Rfilter
TPS2042
Cfilter
V(pullup) R(FILTER) R(FILTER) OUT1 OUT2 C(FILTER)
Controller
Figure Filter Self/Bus Powered Hybrid Many available self-powered hubs designed switch bus-powered mode when local power available. TPS2041 TPS2021 used upstream vbus power line, shown Figure prevent power flow upstream. disable signal should used turn power switch when local power supply present.
TPS202x/3x TPS204x/5x Power Distribution
Self-Powered Port Protection Topologies
Upstream Data Port
Upstream Voltage Unit Load (max)
Power Switch TPS2041 On/Off
Controller TUSB2070 TUSB2040 TUSB2140 Downstream Data Port
Regulator TPS7133 TPS7233
Nonremovable Function
On/Off
Current Limit TPS2041/51 TPS2042/52 TPS2044/54 TPS2022/23/24 TPS2032/33/34 Current Limit TPS2041/51 TPS2042/52 TPS2044/54 TPS2022/23/24 TPS2032/33/34
mA/Port
Downstream Voltage
On/Off Local Power Supply
mA/Port
Downstream Voltage
Figure Self/Bus Powered Hybrid
SLVA049
Summary
Summary
Texas Instruments power management products meet exceed voltage regulation, voltage droop, requirements power distribution system.
TPS202x/3x TPS204x/5x Power Distribution

Mixed-Signal Products SLVA049 IMPORTANT NOTICE Texas Instrum

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