LM2601

LM2601 NSC | Alldatasheet

Document overview

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Technical content

Features

n Detects an AC-DC adapter suitable for battery charging or an airplane or car power line adapter that should not be used for battery charging n Allows the implementation of intelligent switchover circuits for portable systems n LM2601 shuts down automatically when adapter is removed n Low leakage current from battery when not powered n Drives P-channel FETs, no Schottky diodes are required n No reverse inrush current from battery into the adapter output capacitance n Allows for battery capacity gas-gauge calibration under system software/firmware control n Adapter over current threshold programmable with external resistors n Wide input range: 5V - 24V n Available in TSSOP-14 package

Applications

n Portable IAs (Internet Appliances, Information Appliances) n Other Battery Powered Devices Block Diagram 10130901 April 2001 LM2601 Adapter Interface Circuit © 2001 National Semiconductor Corporation DS101309 www.national.com

Ordering Information

Order Number Package Number Package Type Supplied As * LM2601MTC MTC14 TSSOP-14 Rail (94 Units/Rail) LM2601MTCX MTC14 TSSOP-14 Tape and Reel (2500 Units/Reel) * Partial Rails are available, there is no minimum order quantity. Tape and Reel is supplied as full reels only. Pin Description Pin No. Name Function 1 MPS DELAY A capacitor between this pin and ground sets the delay of the MPS risetime. See MPS DELAY description in Typical Application section.

2 MASTER POWER

Bi-directional logic pin. If driven high by an external source, indicates that a battery is powering the power bus. If driven high by the AIC, indicates the adapter is powering the bus. AIC cannot drive MPS low. If there is no valid adapter voltage present, the pin is not an output but a high impedance logic input. The input is pulled-down via an internal 40k resistor.

3 ADAPTER

Logic input pin. Active high. Grants permission to the adapter to drive both the power bus and the MPS signal.

4 ADAPTER

Logic output pin. High when 12 volts < VADAPTER < 17 volts. The output typically has 40k pull-down resistor. The source current is not internally limited and the part can be damaged if the output is shorted to ground when driven HIGH.

5 CHARGER

Logic output pin. High when V ADAPTER > 17 volts. The output typically has 40k pull-down resistor. The source current is not internally limited and the part can be damaged if the output is shorted to ground when driven HIGH. 9 GND IC ground pin. 10 DISCONNECT Drives the gate of the disconnect P-ch FET. 11 BACKFEED Drives the gate of the backfeed P-ch FET.

12 DIRECTION

Connection for current sense resistor to control BACKFEED. 13 PEAK SENSE Connection for current sense resistor to control DISCONNECT. 14 V ADAPTER Power input pin. Output of AC adapter, auto adapter or airline adapter. LM2601 www.national.com 2

Absolute Maximum Ratings (Note 1) If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. V ADAPTER −0.3V to 28V VPEAK SENSE ,VDIRECTION SENSE , VBACKFEED ,V DISCONNECT −0.3V to VADAPTER VADAPTER ENABLE , VMASTER POWER SOURCE −0.3V to 5.5V VMPS DELAY −0.3V to 2V Storage Temperature −40˚C to 125˚C ESD Ratings Human Body Model (Note 2) Machine Model (Note 3) 2kV 200V Operating Ratings(Note 1) Supply Voltage (VADAPTER ) 5 Vt o2 4 V Ambient Temp. Range −20˚C to 70˚C Junction Temp. Range −20˚C to 85˚C

Electrical Characteristics

Limits with standard typeface apply for TJ = 25˚C, and limits inboldface typeapply over the full temperature range (Note 4) Symbol Parameter Conditions Min Typ Max Units VAE Adapter Enable - 3V- or 5V-CMOS or TTL Logic Input High Low 2.0 0.8 V VAP, CP Logic Output Voltage Adapter present, Charger present High Low, ISINK = 5µA 2.9 3.1 0.25 0.6 V VMPS I Master Power Source 5V-CMOS Logic Input High Low 4.0 0.8 V VMPS O Logic Output Voltage Master Power Source VADAPTER > 5.8V High Low 4.5 4.75 0.05 0.5 V V ADAPTER Adapter Voltage for VAP Low-to-High Transition 11.7 12.0 12.3 V Hysteresis 1.8 2.0 2.2 VCHARGER Adapter Voltage for VCP Low-to-High Transition 16.5 17.0 17.4 V Hysteresis 0.08 0.10 0.12 ΔVBACKFEED Current Sense Differential Voltage Threshold for Driving Backfeed FET Vadapter − Direction sense, VADAPTER =5 V 91 7 mV ΔVDISCONNECT Current Sense Differential Voltage Threshold for Driving Disconnect FET Vadapter − Peak sense, VADAPTER = 24V 127 125 135 143 145 mV VBACKFEED , FET Control Voltage V ADAPTER > 11V High VADAPTER - 0.5V V VDISCONNECT VADAPTER > 11V Low VADAPTER - 10V or GND+0.5V, whichever is greater tDRIVE Rise/Fall Time of FET Drive (Note 5) VADAPTER = 10V C Load = 3000pF 3 6 µS IQ Quiescent Current V ADAPTER = 24V 2 10 mA IL,B, IL,D Leakage Current into Backfeed or Disconnect V ADAPTER =0 V VBACKFEED ,V DISCONNECT = 18V 1 15 µA IL,AE Input Current into Adapter Enable Input VAE = 3.3V, Backfeed/Disconnect = 18V 50 µA IL, MPS Input Current into MPS Input V MPS = 5.5V 175 µA TC DELAY Delay Time Temperature Coefficient 4000 ppm/˚C Note 1:Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the ElectricalCharacteristics. Note 2:The human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. Note 3:The machine model is a 200pF capacitor discharged directly into each pin. All pins are rated for 200V except pins 4 and 5 which are rated for 100V. Note 4:Datasheet min/max specification limits are guaranteed by design, test, or statistical analysis. LM2601 www.national.com3

Electrical Characteristics(Continued) Note 5:Adapter Enable input is used to change the state of Disconnect, Direction Sense input is used to change the state of Backfeed. a. Fall time is measured as the time it takes Backfeed or Disconnect voltage to go from a high level (approx. VADAPTER − 0.5V) to (VADAPTER − 4V) after the signal is initiated at Adapter Enable or Direction Sense. b. Rise time is measured as the time it takes Backfeed or Disconnect voltage to go from a low level (approx. 0.5V) to (VADAPTER − 2V) after the signal is initiated at Adapter Enable or Direction Sense. Typical Application 10130903 Notes 1. R SENSE value should be selected to guarantee that a programmed over current will cause a voltage drop across R SENSE of approx. 135mV. If a higher value of R SENSE has to be selected then R1/R3 resistor divider should be used to scale the voltage drop down. 2. Internal and external circuits associated with Direction Sense and Backfeed FET pins allow to emulate a Schot- tky diode functionality with much lower forward voltage drop and, therefore, with much lower power dissipation. R2/R4 resistor divider programs the backfeed current protection threshold. The backfeed FET Q1 turns off when the backfeed current pulse level causes more than 9 mV (typical value) voltage drop between V adapterpin and Direction Sense pin. 3. Voltage difference (VDIRECTION SENSE -V ADAPTER ) must be higher than 20mV to reliably isolate the adapter in case of leakage. 4. R5 and R6 prevent the FETs from turning on unless driven by LM2601. 5. C DELAY value can be calculated from the following for- mula: C DELAY (nF) = TDELAY (µs)/90 at 25˚C 6. T DELAY temperature coefficient equals 4000ppm/˚C. See also the Typical Delay Time vs. Temperature graph. 7. Pin Master Power Source (MPS) should be connected to System Management Controller’s (SMC) and battery packs’ GPIOs. When SMC detects a powered AC adapter via active signals at Charger Present or Adapter Present outputs, it asserts Adapter Enable signal and isolates the battery pack(s). Adapter Enable signal turns the Disconnect FET on. When the AC adapter is un- plugged or powered off, SMC enables one of the system battery packs. The battery packs’ embedded controller starts driving the logic MPS signal high that turns the Disconnect FET off. LM2601 www.national.com 4

Typical Delay Time vs. Temperature 10130905

Application Information

The adapter interface circuit (AIC) IC provides the control functions necessary for use in mating a constant voltage output AC-DC adapter or airline adapter to a notebook com- puter system or a portable device. It allows optimal battery charging during computer operation, and allows battery dis- charge for battery gas gauge calibration. It receives control signals from the notebook computer, monitors input current from the adapter, provides adapter voltage status to the notebook system management microcontroller (or″embed- ded controller″), and appropriately drives MOSFET switches to electrically connect the adapter to the computer. AIC will allow a system designer to solve various power management tasks typical for an adapter powered systems containing a rechargeable battery. When a notebook computer is being powered from a battery and the adapter is plugged in, the computer should start drawing power from the adapter, not from the battery. The most time efficient charging scenario is when a computer draws the full rated current from a constant voltage adapter. The computer uses what it needs to run, and passes all remaining power on to the battery for charging. The com- puter should be able to automatically refuse to charge a battery when powered from an airplane power line. It may be necessary sometimes to have a computer fully discharging the battery and then fully recharging it (for battery gas gauge calibration purposes) while being powered by an AC adapter. AIC will also allow a computer to prevent backfeeding cur- rent into an adapter if the adapter is not powered while being plugged into the computer (some of existing adapters can draw current from the computer under this conditions for charging the AC adapter output bulk capacitance from the computer battery). While the lowest usable adapter voltage is about 9.5V, that is V ADAPTER = 11.7V minus 2.2V hysteresis, AIC is operational down to VADAPTER = 5V. This means that AIC will not gen- erate false readings down to VADAPTER = 5V. Such false readings would be MPS = HIGH, ADAPTER PRESENT = HIGH, CHARGER PRESENT = HIGH. AIC determines usable voltage ranges by comparing V ADAPTER with an internal 2.5V voltage reference (see also Electrical Characteristics). AIC detects operating current limit and leakage current limit into the adapter jack by differential sensing across current sense resistor R SENSE either directly or scaled down by resistor dividers R1/R3 and R2/R4. When designing the LM2601 into a system it may be neces- sary to consider ESD protection requirements for the adapter jack according to your system design spec. LM2601 www.national.com5

Physical Dimensionsinches (millimeters) unless otherwise noted 14-Lead Thin Shrink Small-Outline Package For Ordering, Refer to Ordering Information Table LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. National Semiconductor Corporation Americas Tel: 1-800-272-9959 Fax: 1-800-737-7018 Email: support@nsc.com National Semiconductor Europe Fax: +49 (0) 180-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 National Semiconductor Asia Pacific Customer Response Group Tel: 65-2544466 Fax: 65-2504466 Email: ap.support@nsc.com National Semiconductor Japan Ltd. Tel: 81-3-5639-7560 Fax: 81-3-5639-7507 www.national.com LM2601 Adapter Interface Circuit National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.