常用电源芯片使用 PPT
电源管理ic
电源管理IC技术与发展趋势
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01
电源管理IC简介及其重要性
电源管理IC的定义与作用
电源管理IC（Power Management Integrated Circuit）是一种集成化的电源管理芯片
• 负责对电子设备中的电源进行高效、 稳定、安全的管理和控制 • 实现电源转换、电压调节、电池管理 等功能 • 保障电子设备在各种工作状态下的稳 定运行和节能效果
航能力
数码相机：负责数码相 机的电源管理和充电功 能，保障相机的稳定工
作
电源管理IC在工业与汽车电子中的应用案例
01 工业自动化设备：负责设备的电源管理和保护功能，提高设备的可靠性和稳定性 02 汽车电子控制系统：负责汽车的电源管理和保护功能，保障汽车的安全行驶 03 通信基站：负责基站的电源管理和节能功能，降低基站的运行成本和能耗
• 高效、高密度的电源管理场景：如LED照明、移动电源等 • 对电源效率和体积要求较高的场景：如笔记本电脑、平 板电脑等
电池管理IC技术原理与应用
电池管理IC技术原理
• 对电池进行充电、放电、保护等管理 • 提高电池的使用寿命和续航能力
电池管理IC的应用
• 便携式电子设备：如智能手机、数码相机等 • 无线通信设备：如蓝牙耳机、无线鼠标等 • 电动汽车、储能系统等领域
电源管理IC的设计难点
• 如何在有限的芯片面积内实现高性能的电源管理功能 • 如何在提高电源管理IC性能的同时降低功耗 • 如何在保证电源管理IC性能的同时降低成本
电源管理IC的选型原则与方法
电源管理IC的选型原则
• 根据电子设备的应用场景和性能要求选择合适的电源管理IC • 考虑电源管理IC的功耗、效率、稳定性、成本等因素
MCP73842 电源芯片
2004 Microchip Technology Inc.DS21823B-page 1MMCP73841/2/3/4Features•Linear Charge Management Controllers •High-Accuracy Preset Voltage Regulation:-+ 0.5% (max)•Four Preset Voltage Regulation Options:- 4.1V - MCP73841-4.1, MCP73843-4.1- 4.2V - MCP73841-4.2, MCP73843-4.2-8.2V - MCP73842-8.2, MCP73844-8.2-8.4V - MCP73842-8.4, MCP73844-8.4•Programmable Charge Current•Programmable Safety Charge Timers •Preconditioning of Deeply Depleted Cells •Automatic End-of-Charge Control•Optional Continuous Cell Temperature Monitoring (MCP73841 and MCP73842)•Charge Status Output for Direct LED Drive •Automatic Power-Down when Input Power Removed•T emperature Range: -40°C to 85°C•Packaging: MSOP-10 - MCP73841, MCP73842MSOP-8 - MCP73843, MCP73844Applications•Lithium-Ion/Lithium-Polymer Battery Chargers •Personal Data Assistants •Cellular Telephones •Hand-Held Instruments •Cradle Chargers •Digital Cameras •MP3 PlayersTypical Application CircuitDescriptionThe MCP7384X family of devices are highly advanced linear charge management controllers for use in space-limited, cost-sensitive applications. The MCP73841 and MCP73842 combine high accuracy,constant-voltage, constant-current regulation, cell pre-conditioning, cell temperature monitoring, advanced safety timers, automatic charge termination and charge status indication in space-saving, 10-pin MSOP packages. The MCP73841 and MCP73842provide complete, fully-functional, stand-alone charge management solutions.The MCP73843 and MCP73844 employ all the features of the MCP73841 and MCP73842, with the exception of the cell temperature monitor. The MCP73843 and MCP73844 are offered in 8-pin MSOP packages.The MCP73841 and MCP73843 are designed for applications utilizing single-cell Lithium-Ion or Lithium-Polymer battery packs. Two preset voltage regulation options are available (4.1V and 4.2V) for use with either coke or graphite anodes. The MCP73841 and MCP73843 operate with an input voltage range of 4.5V to 12V.The MCP73842 and MCP73844 are designed for applications utilizing dual series cell Lithium-Ion or Lithium-Polymer battery packs. Two preset voltage regulation options are available (8.2V and 8.4V). The MCP73842 and MCP73844 operate with an input voltage range of 8.7V to 12V.The MCP7384X family of devices are fully specified over the ambient temperature range of -40°C to +85°C.Package Types+-V SS DRV SENSE V DD V BATSTAT136712MCP73843810µF10µF 100k Ω100m Ω5V SingleLithium-Ion CellNDS8434MA2Q7051A Lithium-Ion Battery ChargerEN5TIMER40.1µF10-Pin MSOPSENSEV DD STAT1ENDRV V BAT V SS TIMER12348765M C P 73843M C P 738448-Pin MSOPV DD STAT1EN THREFV BAT V SS TIMER THERM23459876M C P 73841M C P 73842SENSEDRV 110Advanced Single or Dual Cell Lithium-Ion/Lithium-Polymer Charge Management ControllersMCP73841/2/3/4DS21823B-page 2 2004 Microchip Technology Inc.Functional Block DiagramCharge Termination Comparator Voltage Control AmplifierV REFI REG /10Precondition ControlCharge_ok PreconV DDCharge Current Control Amplifier+–V REF V REFPrecondition Comp .V BAT V SS DRV90k Ω90k Ω10k Ω10k Ω+–Charge Current AmplifierV DD SENSEMCP73841 and MCP73842 Only300k Ω (825k Ω)12k Ω1k ΩUVLOComparatorV UVLOT emperature ComparatorsBias and Reference GeneratorV UVLOV REF (1.2V)Power-On DelayV REFOscillatorConstant-Voltage/ Recharge Comp.Charge Control, Charge Timers,And Status LogicDrv Stat 1Charge_okI REG /10THERMENTIMERSTAT1THREF100k Ω50k Ω50k Ω74.21k Ω0.79k Ω150.02k Ω5.15k Ω (4.29k Ω)+-+-+-+-+-+-+-MCP73841/2/3/41.0ELECTRICALCHARACTERISTICSAbsolute Maximum Ratings†V DD.................................................................................13.5V All inputs and outputs w.r.t. V SS................-0.3 to (V DD+0.3)V Current at DRV Pin ......................................................±4mA Current at STAT1 Pin .................................................±30mA Maximum Junction Temperature, T J.............................150°C Storage temperature.....................................-65°C to +150°C ESD protection on all pins:Human Body Model (1.5kΩ in Series with 100pF).......≥ 2kV Machine Model (200pF, No Series Resistance).............200V *Notice: Stresses above those listed under “Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational listings of this specification is not implied. Expo-sure to maximum rating conditions for extended periods may affect device reliability.DC CHARACTERISTICSElectrical Specifications: Unless otherwise indicated, all limits apply for V DD= [V REG(Typ)+0.3V] to 12V, T A = -40°C to +85°C. Typical values are at +25°C, V DD = [V REG(Typ) + 1V].Parameters Sym Min Typ Max Units ConditionsSupply InputSupply Voltage V DDMCP73841, MCP73843 4.5–12VMCP73842, MCP738448.7–12VSupply Current I SS––0.250.7544µAmADisabledOperatingV DD =V REG(Typ)+1VUVLO Start Threshold V STARTMCP73841, MCP73843 4.25 4.45 4.60V V DD Low-to-High MCP73842, MCP738448.458.658.90V V DD Low-to-High UVLO Stop Threshold V STOPMCP73841, MCP73843 4.20 4.40 4.55V V DD High-to-Low MCP73842, MCP738448.408.608.85V V DD High-to-Low Voltage Regulation (Constant-Voltage Mode)Regulated Output Voltage V REGMCP73841-4.1, MCP73843-4.14.079 4.1 4.121V V DD = [V REG(Typ)+1V], I OUT = 10mA,T A = -5°C to +55°CMCP73841-4.2, MCP73843-4.24.179 4.2 4.221V V DD = [V REG(Typ)+1V], I OUT = 10mA,T A = -5°C to +55°CMCP73842-8.2, MCP73844-8.28.1598.28.241V V DD = [V REG(Typ)+1V], I OUT = 10mA,T A = -5°C to +55°CMCP73842-8.4, MCP73844-8.48.3588.48.442V V DD = [V REG(Typ)+1V], I OUT = 10mA,T A = -5°C to +55°CLine Regulation|(∆V BAT/V BAT)|/∆V DD –0.0250.25%/V V DD = [V REG(Typ)+1V] to 12V,I OUT = 10mALoad Regulation|∆V BAT|/V BAT–0.010.25%I OUT = 10mA to 150mA,V DD = [V REG(Typ)+1V]Supply Ripple Attenuation PSRR–-58–dB I OUT = 10mA, 100Hz–-42–dB I OUT = 10mA, 1kHz–-30–dB I OUT = 10mA, 10kHzOutput Reverse LeakageCurrentI DISCHARGE–0.41µA V DD Floating, V BAT = V REG(Typ) Current Regulation (Fast Charge Constant-Current Mode)Fast Charge Current Regulation Threshold V FCS100110120mV V DD – V SENSE,T A = -5°C to +55°C2004 Microchip Technology Inc.DS21823B-page 3MCP73841/2/3/4DS21823B-page 4 2004 Microchip Technology Inc.Preconditioning Current Regulation (Trickle Charge Constant-Current Mode)Precondition Current Regulation ThresholdV PCS 51015mVV DD – V SENSE,T A = -5°C to +55°CPrecondition Threshold VoltageV PTHMCP73841-4.1,MCP73843-4.1 2.70 2.80 2.90V V BAT Low-to-High MCP73841-4.2,MCP73843-4.2 2.75 2.85 2.95V V BAT Low-to-High MCP73842-8.2,MCP73844-8.2 5.40 5.60 5.80V V BAT Low-to-High MCP73842-8.4,MCP73844-8.4 5.505.705.90VV BAT Low-to-HighCharge TerminationCharge Termination Threshold V TCS4710mVV DD – V SENSE,T A = -5°C to +55°CAutomatic Recharge Recharge Threshold VoltageV RTHMCP73841,MCP73843V REG -300mV V REG -200mV V REG -100mV V V BAT High-to-Low MCP73842,MCP73844V REG -600mV V REG -400mV V REG -200mVVV BAT High-to-LowExternal MOSFET Gate Drive Gate Drive CurrentI DRV –2–mA Sink, CV Mode –-0.5–mA Source, CV Mode Gate Drive Minimum Voltage V DRVMIN –– 1.0V V DD = 4.5V Gate - Source Clamp Voltage V GS -7.0–-4.5V V DD = 12.0VThermistor Reference - MCP73841, MCP73842Thermistor Reference Output VoltageV THREF 2.475 2.55 2.625V T A = +25°C, V DD = V REG (Typ)+1V,I THREF = 0mAT emperature Coefficient TC THREF –+50–ppm/°C Thermistor Reference Source CurrentI THREF 200––µA Thermistor Reference Line Regulation|(∆V THREF /V THREF )|/∆V DD –0.10.25%/VV DD =[V REG (Typ)+1V] to 12V Thermistor Reference Load Regulation∆V THREF /V THREF–0.010.10%I THREF = 0mA to 0.20mAThermistor Comparator - MCP73841, MCP73842Upper Trip Threshold V T1 1.18 1.25 1.32V Upper Trip Point Hysteresis V T1HYS –-50–mV Lower Trip Threshold V T20.590.620.66V Lower Trip Point Hysteresis V T2HYS –80–mV Input Bias Current |I BIAS |––2µAStatus Indicator Sink Current I SINK 4712mA Low Output Voltage V OL –200400mV I SINK = 1mAInput Leakage CurrentI LK–0.011µAI SINK = 0mA, V STAT1 = 12VDC CHARACTERISTICS (CONTINUED)Electrical Specifications: Unless otherwise indicated, all limits apply for V DD = [V REG (Typ)+0.3V] to 12V, T A = -40°C to +85°C.Typical values are at +25°C, V DD = [V REG (Typ) + 1V].ParametersSym Min Typ Max Units Conditions2004 Microchip Technology Inc.DS21823B-page 5MCP73841/2/3/4AC CHARACTERISTICSTEMPERATURE SPECIFICATIONSEnable InputInput High-Voltage Level V IH 1.4-–V Input Low-Voltage Level V IL –-0.8V Input Leakage CurrentI LK–0.011µAV ENABLE = 12VElectrical Specifications: Unless otherwise indicated, all limits apply for V DD = [V REG (Typ)+0.3V] to 12V, T A = -40°C to +85°C. Typ-ical values are at +25°C, V DD = [V REG (Typ)+1V].ParametersSym Min Typ Max Units ConditionsUVLO Start Delay t START––5msecV DD Low-to-HighCurrent Regulation Transition Time Out of Preconditioningt DELAY ––1msec V BAT < V PTH to V BAT > V PTH Current Rise Time Out of Preconditioningt RISE ––1msec I OUT Rising to 90% of I REG Fast Charge Safety Timer Period t FAST1.21.41.6HoursC TIMER = 0.1µFPreconditioning Current Regulation Preconditioning Charge Safety Timer Period t PRECON506070MinutesC TIMER = 0.1µFCharge TerminationElapsed Time Termination Period t TERM2.52.93.3HoursC TIMER = 0.1µFStatus Indicators Status Output turn-off t OFF ––200µsec I SINK = 10mA to 0mA Status Output turn-ont ON––200µsecI SINK = 0mA to 10mAElectrical Specifications: Unless otherwise specified, all limits apply for V DD = [V REG (Typ)+0.3V] to 12V.Typical values are at +25°C, V DD = [V REG (Typ)+1.0V].ParametersSymMinTypMaxUnitsConditionsTemperature Ranges Specified Temperature Range T A -40+85°C Operating Temperature Range T A -40+125°C Storage T emperature Range T A-65+150°CThermal Package Resistances Thermal Resistance, MSOP-10θJA 113°C/W 4-Layer JC51-7 Standard Board, Natural ConvectionThermal Resistance, MSOP-8θJA206°C/WSingle-Layer SEMI G42-88 Board, Natural ConvectionDC CHARACTERISTICS (CONTINUED)Electrical Specifications: Unless otherwise indicated, all limits apply for V DD = [V REG (Typ)+0.3V] to 12V, T A = -40°C to +85°C.Typical values are at +25°C, V DD = [V REG (Typ) + 1V].ParametersSymMinTypMaxUnitsConditionsMCP73841/2/3/4DS21823B-page 6 2004 Microchip Technology Inc.2.0TYPICAL PERFORMANCE CURVESNote: Unless otherwise indicated, V DD = [V REG (Typ) + 1V], I OUT = 10mA and T A = +25°C.FIGURE 2-1:Battery Regulation Voltage (V BAT ) vs. Charge Current (I OUT ).FIGURE 2-2:Battery Regulation Voltage (V BAT ) vs. Supply Voltage (V DD ).FIGURE 2-3:Battery Regulation Voltage (V BAT ) vs. Supply Voltage (V DD ).FIGURE 2-4:Supply Current (I SS ) vs. Charge Current (I OUT ).FIGURE 2-5:Supply Current (I SS ) vs. Supply Voltage (V DD ).FIGURE 2-6:Supply Current (I SS ) vs. Supply Voltage (V DD ).Note:The graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. The performance characteristics listed herein are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore outside the warranted range.MCP73841/2/3/4 Note: Unless otherwise indicated, V DD = [V REG(Typ) + 1V], I OUT = 10mA and T A= +25°C.FIGURE 2-7:Battery Regulation Voltage (V BAT) vs. Charge Current (I OUT).FIGURE 2-8:Battery Regulation Voltage (V BAT) vs. Supply Voltage (V DD).FIGURE 2-9:Battery Regulation Voltage (V BAT) vs. Supply Voltage (V DD).FIGURE 2-10:Supply Current (I SS) vs. Charge Current (I OUT).FIGURE 2-11:Supply Current (I SS) vs. Supply Voltage (V DD).FIGURE 2-12:Supply Current (I SS) vs. Supply Voltage (V DD).2004 Microchip Technology Inc.DS21823B-page 7MCP73841/2/3/4DS21823B-page 8 2004 Microchip Technology Inc.Note: Unless otherwise indicated, V DD = [V REG (Typ) + 1V], I OUT = 10mA and T A = +25°C.FIGURE 2-13:Output Reverse Leakage Current (I DISCHARGE ) vs. Battery Voltage (V BAT ).FIGURE 2-14:Thermistor Reference Voltage (V THREF ) vs. Thermistor Bias Current (I THREF ).FIGURE 2-15:Thermistor Reference Voltage (V THREF ) vs. Supply Voltage (V DD ).FIGURE 2-16:Output Reverse Leakage Current (I DISCHARGE ) vs. Battery Voltage (V BAT ).FIGURE 2-17:Thermistor Reference Voltage (V THREF ) vs. Thermistor Bias Current (I THREF ).FIGURE 2-18:Thermistor Reference Voltage (V THREF ) vs. Supply Voltage (V DD ).MCP73841/2/3/4 Note: Unless otherwise indicated, V DD = [V REG(Typ) + 1V], I OUT = 10mA and T A= +25°C.FIGURE 2-19:Line Transient Response. FIGURE 2-20:Load Transient Response. FIGURE 2-21:Power Supply Ripple Rejection.FIGURE 2-22:Line Transient Response. FIGURE 2-23:Load Transient Response. FIGURE 2-24:Power Supply Ripple Rejection.V DDV BAT MCP73841-4.2VV DD Stepped From 5.2V to 6.2VI OUT = 10 mAC OUT = 10 µF, X7R, CeramicMCP73841-4.2VV DD = 5.2VC OUT = 10 µF, X7R, CeramicV BATI OUT100 mA10 mAV DDV BAT MCP73841-4.2VV DD Stepped From 5.2V to 6.2VI OUT = 500 mAC OUT = 10 µF, X7R, CeramicV BAT MCP73841-4.2VV DD = 5.2VC OUT = 10 µF, X7R, CeramicI OUT500 mA10 mA2004 Microchip Technology Inc.DS21823B-page 9MCP73841/2/3/4DS21823B-page 10 2004 Microchip Technology Inc.3.0PIN DESCRIPTIONSThe descriptions of the pins are listed in Table 3-1.TABLE 3-1:PIN DESCRIPTION TABLE3.1Charge Current Sense Input(SENSE)Charge current is sensed via the voltage developed across an external precision sense resistor. The sense resistor must be placed between the supply voltage (V DD ) and the external pass transistor (Q1). A 220m Ωsense resistor produces a fast charge current of 500mA, typically.3.2Battery Management Input Supply (V DD )A supply voltage of [V REG (Typ) + 0.3V] to 12V is recommended. Bypass to V SS with a minimum of 4.7µF.3.3Charge Status Output (STAT1)Current limited, open-drain drive for direct connection to a LED for charge status indication. Alternatively, a pull-up resistor can be applied for interfacing to a host microcontroller.3.4Logic Enable (EN)Input to force charge termination, initiate charge, clear faults or disable automatic recharge.3.5Cell Temperature Sensor Bias (THREF)Voltage reference to bias external thermistor for continuous cell temperature monitoring and prequalification.3.6Cell Temperature Sensor Input (THERM)Input for an external thermistor for continuous cell-temperature monitoring and pre-qualification. Apply a voltage equal to 0.85V to disable temperature-sensing.3.7Timer Set (TIMER)All safety timers are scaled by C TIMER /0.1µF .3.8Battery Management 0V Reference (V SS )Connect to negative terminal of battery.3.9Battery Voltage Sense (V BAT )Voltage sense input. Connect to positive terminal of battery. Bypass to V SS with a minimum of 4.7µF to ensure loop stability when the battery is disconnected.A precision internal resistor divider regulates the final voltage on this pin to V REG .3.10Drive Output (DRV)Direct output drive of an external P-channel MOSFET for current and voltage regulation.MCP73841, MCP73842 Pin No.MCP73843, MCP73844Pin No.Name Function11SENSE Charge Current Sense Input 22V DD Battery Management Input Supply 33STAT1Charge Status Output 44EN Logic Enable5—THREF Cell T emperature Sensor Bias 6—THERM Cell T emperature Sensor Input 75TIMER Timer Set86V SS Battery Management 0V Reference 97V BAT Battery Voltage Sense 108DRVDrive OutputMCP73841/2/3/44.0DEVICE OVERVIEWThe MCP7384X family of devices are highly advanced, linear charge management controllers. Figure4-1 depicts the operational flow algorithm from charge initiation to completion and automatic recharge.4.1Charge Qualification andPreconditioningUpon insertion of a battery or application of an external supply, the MCP7384X family of devices automatically perform a series of safety checks to qualify the charge. The input source voltage must be above the undervoltage lockout threshold, the enable pin must be above the logic-high level and the cell temperature monitor must be within the upper and lower thresholds. The cell temperature monitor applies to both the MCP73841 and MCP73842, with the qualification parameters being continuously monitored. Deviation beyond the limits automatically suspends or terminates the charge cycle.Once the qualification parameters have been met, the MCP7384X initiates a charge cycle. The charge status output is pulled low throughout the charge cycle (see Table5-1 for charge status outputs). If the battery voltage is below the preconditioning threshold (V PTH), the MCP7384X preconditions the battery with a trickle-charge. The preconditioning current is set to approximately 10% of the fast charge regulation current. The preconditioning trickle-charge safely replenishes deeply depleted cells and minimizes heat dissipation in the external pass transistor during the initial charge cycle. If the battery voltage has not exceeded the preconditioning threshold before the preconditioning timer has expired, a fault is indicated and the charge cycle is terminated.4.2Constant-Current Regulation –Fast ChargePreconditioning ends and fast charging begins, when the battery voltage exceeds the preconditioning threshold. Fast charge regulates to a constant-current, I REG, based on the supply voltage minus the voltage at the SENSE input (V FCS) developed by the drop across an external sense resistor (R SENSE). Fast charge continues until the battery voltage reaches the regulation voltage (V REG); or until the fast charge timer expires. In this case, a fault is indicated and the charge cycle is terminated.4.3Constant-Voltage RegulationWhen the battery voltage reaches the regulation voltage (V REG), constant-voltage regulation begins. The MCP7384X monitors the battery voltage at the V BAT pin. This input is tied directly to the positive terminal of the battery. The MCP7384X is offered in four fixed-voltage versions for single or dual series cell battery packs with either coke or graphite anodes:- 4.1V (MCP73841-4.1, MCP73843-4.1)- 4.2V (MCP73841-4.2, MCP73843-4.2)-8.2V (MCP73842-8.2, MCP73844-8.2)-8.4V (MCP73842-8.4, MCP73844-8.4)4.4Charge Cycle Completion andAutomatic Re-ChargeThe MCP7384X monitors the charging current during the constant-voltage regulation phase. The charge cycle is considered complete when the charge current has diminished below approximately 7% of the regulation current (I REG) or the elapsed timer has expired.The MCP7384X automatically begins a new charge cycle when the battery voltage falls below the recharge threshold (V RTH), assuming all the qualification parameters are met.2004 Microchip Technology Inc.DS21823B-page 11MCP73841/2/3/45.0DETAILED DESCRIPTION5.1Analog Circuitry5.1.1CHARGE CURRENT SENSE INPUT (SENSE)Fast charge current regulation is maintained by the voltage drop developed across an external sense resistor (R SENSE ) applied to the SENSE input pin. The following formula calculates the value for R SENSE :The preconditioning trickle-charge current and the charge termination current are scaled to approximately 10% and 7% of I REG , respectively.5.1.2BATTERY MANAGEMENT INPUT SUPPLY (V DD )The V DD input is the input supply to the MCP7384X.The MCP7384X automatically enters a power-down mode if the voltage on the V DD input falls below the undervoltage lockout voltage (V STOP ). This feature prevents draining the battery pack when the V DD supply is not present.5.1.3CELL TEMPERATURE SENSOR BIAS (THREF)A 2.55V voltage reference is provided to bias an external thermistor for continuous cell temperature monitoring and pre-qualification. A ratio metric window comparison is performed at threshold levels of V THREF /2 and V THREF /4. Cell temperature monitoring is provided by both the MCP73841 and MCP73842.5.1.4CELL TEMPERATURE SENSOR INPUT (THERM)The MCP73841 and MCP73842 continuously monitor temperature by comparing the voltage between the THERM input and V SS with the upper and lower temperature thresholds. A negative or positive temperature coefficient (NTC or PTC) thermistor and an external voltage divider typically develop this voltage. The temperature-sensing circuit has its own reference, to which it performs a ratio metric comparison. Therefore, it is immune to fluctuations in the supply input (V DD ). The temperature-sensing circuit is removed from the system when V DD is not applied,eliminating additional discharge of the battery pack.Figure 6-1 depicts a typical application circuit with connection of the THERM input. The resistor values of R T1 and R T2 are calculated with the following equations.Applying a voltage equal to 0.85V to the THERM input disables temperature monitoring.5.1.5TIMER SET INPUT (TIMER)The TIMER input programs the period of the safety timers by placing a timing capacitor (C TIMER ) between the TIMER input pin and V SS . Three safety timers are programmed via the timing capacitor.The preconditioning timer starts after qualification and resets when the charge cycle transitions to the con-stant-current, fast charge phase. The fast charge and elapsed timers start once the MCP7384X transitions from preconditioning. The fast charge timer resets when the charge cycle transitions to the constant-volt-age phase. The elapsed timer will expire and terminate the charge if the sensed current does not diminish below the termination threshold.MCP73841/2/3/45.1.6BATTERY VOLTAGE SENSE (V BAT )The MCP7384X monitors the battery voltage at the V BAT pin. This input is tied directly to the positive terminal of the battery. The MCP7384X is offered in four fixed-voltage versions for single or dual series cell battery packs, with either coke or graphite anodes:- 4.1V (MCP73841-4.1, MCP73843-4.1)- 4.2V (MCP73841-4.2, MCP73843-4.2)-8.2V (MCP73842-8.2, MCP73844-8.2)-8.4V (MCP73842-8.4, MCP73844-8.4)5.1.7DRIVE OUTPUT (DRV)The MCP7384X controls the gate drive to an external P-channel MOSFET . The P-channel MOSFET is controlled in the linear region regulating current and voltage supplied to the cell. The drive output is automatically turned off when the voltage on the V DD input falls below the undervoltage lockout voltage (V STOP ).5.2Digital Circuitry5.2.1CHARGE STATUS OUTPUT (STAT1)A status output provides information on the state-of-charge. The current-limited, open-drain output can be used to illuminate an external LED. Optionally, a pull-up resistor can be used on the output for communication with a host microcontroller. T able 5-1 summarizes the state of the status output during a charge cycle.The flashing rate (1Hz) is based off a timer capacitor (C TIMER ) of 0.1µF. The rate will vary based on the value of the timer capacitor.5.2.2LOGIC ENABLE (EN)The logic-enable input pin (EN) can be used to terminate a charge anytime during the charge cycle,initiate a charge cycle or initiate a recharge cycle.Applying a logic-high input signal to the EN pin, or tying it to the input source, enables the device. Applying a logic-low input signal disables the device and terminates a charge cycle. When disabled, the device’s supply current is reduced to 0.25µA, typically.MCP73841/2/3/46.0APPLICATIONSThe MCP7384X is designed to operate in conjunction with either a host microcontroller or in stand-alone applications. The MCP7384X provides the preferred charge algorithm for Lithium-Ion and Lithium-Polymercells: constant-current followed by constant-voltage.Figure 6-1 depicts a typical stand-alone application circuit, while Figure 6-2 depicts the accompanying charge profile.FIGURE 6-1:Typical Application Circuit.FIGURE 6-2:Typical Charge Profile.MCP73841/2/3/4DS21823B-page 16 2004 Microchip Technology Inc.6.1Application Circuit DesignDue to the low efficiency of linear charging, the most important factors are thermal design and cost, which are a direct function of the input voltage, output current and thermal impedance between the external P-channel pass transistor and the ambient cooling air. The worst-case situation occurs when the device has transitioned from the preconditioning phase to the constant-current phase. In this situation, the P-channel pass transistor has to dissipate the maximum power. A trade-off must be made between the charge current, cost and thermal requirements of the charger.6.1.1COMPONENT SELECTIONSelection of the external components in Figure 6-1 are crucial to the integrity and reliability of the charging system. The following discussion is intended to be a guide for the component selection process.6.1.1.1Sense ResistorThe preferred fast charge current for Lithium-Ion cells is at the 1C rate, with an absolute maximum current at the 2C rate. For example, a 500mAh battery pack has a preferred fast charge current of 500mA. Charging at this rate provides the shortest charge cycle times without degradation to the battery pack performance or life.The current sense resistor (R SENSE ) is calculated by:For the 500mAh battery pack example, a standard value 220m Ω, 1% resistor provides a typical fast charge current of 500mA and a maximum fast charge current of 551mA. Worst-case power dissipation in the sense resistor is:A Panasonic ® ERJ-6RQFR22V, 220mW, 1%, 1/8W resistor in a standard 0805 package is more than sufficient for this application.A larger value sense resistor will decrease the fast charge current and power dissipation in both the sense resistor and external pass transistor, but will increase charge cycle times. Design trade-offs must be considered to minimize space while maintaining the desired performance.6.1.1.2External Pass TransistorThe external P-channel MOSFET is determined by the gate-to-source threshold voltage, input voltage, output voltage and fast charge current. Therefore, the selected P-channel MOSFET must satisfy the thermal and electrical design requirements.Thermal ConsiderationsThe worst-case power dissipation in the external pass transistor occurs when the input voltage is at the maximum and the device has transitioned from the preconditioning phase to the constant-current phase.In this case, the power dissipation is:Power dissipation with a 5V, ±10% input voltage source, 220m Ω, 1% sense resistor is:Utilizing a Fairchild™ NDS8434 or an International Rectifier IRF7404 mounted on a 1in 2 pad of 2 oz.copper, the junction temperature rise is 75°C,approximately. This would allow for a maximum operating ambient temperature of 75°C.By increasing the size of the copper pad, a higher ambient temperature can be realized, or a lower value sense resistor could be utilized.Alternatively, different package options can be utilized for more or less power dissipation. Again, design trade-offs should be considered to minimize size while maintaining the desired performance.Electrical ConsiderationsThe gate-to-source threshold voltage and R DSON of the external P-channel MOSFET must be considered in the design phase.The worst-case V GS provided by the controller occurs when the input voltage is at the minimum and the fast charge current regulation threshold is at the maximum.The worst-case V GS is:R SENSE V FCSI REG------------=Where:I REG is the desired fast charge current.PowerDissipation 220m Ω551mA 2×66.8mW ==PowerDissipation V DDMAX V PTHMIN –()I REGMAX×=Where:V DDMAX is the maximum input voltage.I REGMAX is the maximum fast charge current.V PTHMIN is the minimum transition threshold voltage.PowerDissipation 5.5V 2.75V –()551mA × 1.52W==V GS V DRVMAX V DDMIN V FCSMAX )–(–=Where:V DRVMAX is the maximum sink voltage at the V DRV outputV DDMIN is the minimum input voltage source V FCSMAX is the maximum fast charge current regulation threshold。
《DCDC电源电路经验》课件
通信系统中的DCDC电源电路
应用背景：通信系统中需要稳定的电源供应 功能：为通信设备提供稳定的电源 特点：高效率、低噪声、高可靠性 应用实例：基站、路由器、交换机等通信设备中的DCDC电源电路
工业控制中的DCDC电源电路
应用领域：工业自 动化、机器人、数 控机床等
功能：提供稳定、 可靠的电源输出
线性DCDC电源电路：优 点是输出电压稳定，缺点 是效率低
开关DCDC电源电路：优 点是效率高，缺点是输出 电压可能不稳定
应用：广泛应用于各种电 子设备，如手机、电脑、 家电等
DCDC电源电路设计
输入输出电压范围
输入电压范围：通常为10-30V
电压精度：一般要求达到±2%或更 高
添加标题
添加标题
DCDC电源电路的控制策略
电压控制模式
优点：简单易行，易于实现
电压控制模式：通过控制输 出电压来调节电源输出
缺点：输出电压可能不稳定， 需要额外的稳压措施
应用：适用于对输出电压要 求不高的场合
电流控制模式
电流模式：通过 控制电流来调节 输出电压
电压模式：通过 控制电压来调节 输出电流
混合模式：结合 电流模式和电压 模式，实现更精 确的控制
法规要求：满足日 益严格的环保和能 效法规要求
应用领域：拓展新 的应用领域，如电 动汽车、可再生能 源等
THANK YOU
汇报人：
减小体积：宽禁带半导体材料可以减小电源电路的体积，提高便携性
提高可靠性：宽禁带半导体材料可以提高电源电路的可靠性，延长使用寿命
降低成本：随着技术的发展，宽禁带半导体材料的成本有望降低，进一步推动其在电源 电路中的应用
未来挑战与展望
技术挑战：提高转 换效率、降低功耗、 提高稳定性等
触发器NE555的应用分析课件
为了满足不同的应用需求， NE555芯片也在向多功能集成 方向发展。例如，将NE555芯 片与其他芯片集成在一起，实 现更复杂的功能。
NE555芯片的未来展望
01
更广泛的应用领域
随着科技的不断发展，NE555芯片的应用领域将更加广泛。除了传统的
定时器、振荡器、信号产生器等领域外，还将拓展到其他领域，如无线
发展。
06
参考文献参考文献来自NE555 Datasheet: This datasheet provides
detailed information about the NE555 IC, including its pinout, specifications, and operation.
NE555 Application Note: This
噪声和干扰问题
总结词
噪声和干扰问题可能影响NE555芯片的输出信号质量。
详细描述
在实际应用中，噪声和干扰可能来自各种来源，如电源噪声、电磁干扰等。这些因素可能影响NE555 芯片的输出信号质量，导致信号失真或不稳定。为了减小噪声和干扰的影响，可以采取一系列措施， 如滤波、屏蔽等。
05
NE555芯片的发展趋势和未来展望
通讯、物联网等。
02
更智能化的控制
随着人工智能技术的不断发展，NE555芯片也将逐渐实现智能化控制。
通过与AI技术的结合，实现对各种应用场景的智能感知、智能控制和智
能优化。
03
更高效的生产工艺
随着制程技术的不断进步，NE555芯片的生产工艺也将更加高效。这将
有助于降低生产成本，提高生产效率，进一步推动NE555芯片的应用和
脉冲宽度调制（PWM）应用
常用模拟开关芯片型号与功能和应用介绍-PPT精选文档
注意：
AD7501，AD7502，AD7503 芯片都是单向多到
一的多路开关，即信号只允许从多个 (8个) 输入端向
一个输出端传送。
单八路模拟开关CD4051
• CD4051相当于一个单刀八掷开关，开关接通哪一通 道，由输入的3位地址码ABC来决定。
当选通Ｅ为 1 时，而输入端Ａ为０时，则 S2 端为 1 ， S1端为０，这时ＶＴ1截止，VT2导通，输出端Ｂ为０， Ａ＝Ｂ，也相当于输入端和输出端接通。 当选通端Ｅ为０时，这时ＶＴ1和ＶＴ2均为截止状 态，电路输出呈高阻状态。 从上面的分析可以看出，只有当选通端Ｅ为高电 平时，模拟开关才会被接通，此时可从Ａ向Ｂ传送信 息；当输入端Ａ为低电平时，模拟开关关闭，停止传 送信息。
AD 7501
14 13 12 11 10 9
... ...
S1 S8
图3.7 AD7501（AD7503）芯片结构及引脚功能
片上所有逻辑输入与TTL／DTL及CMOS 电路兼容。
表3.1 AD7501真值表
A2
0 0 0 0 1 1 1 1 ×
A1
0 0 1 1 0 0 1 1 ×
A0
0 1 0 1 0 1 0 1 ×
二、常用的CMOS模拟开关集成电路
在模拟开关的集成过程中，晶体三极管和场效应 晶体管均可用来做模拟开关的有源器件，实际上，由 于场效应晶体管特性的对称性不存在残余电压等优点， 所以在模拟开关中用的最多的还是场效应晶体管。 • 开关在电路中起接通信号或断开信号的作用。最常见的 可控开关是继电器，当给驱动继电器的驱动电路加高电 平或低电平时，继电器就吸合或释放，其触点接通或断 开电路。 • CMOS模拟开关是一种可控开关，它不象继电器那样可 以用在大电流、高电压场合，只适于处理幅度不超过其 工作电压、电流较小的模拟或数字信号。
开关电源芯片HT2263、2269的基本运用(1)
设备，电子产品，照明产品等等，目前在中国市 场上做得最多的是照明产品，包括节能灯(CFL， 灯具(RLF)，交通信号灯和出口指示灯。 目前全球计有七个国家参与美国环保署推动 的能源之星计划，分别为美国、加拿大、日本、 台湾、澳洲、新西兰、欧盟。
对于小型开关电源的标准如下：
Foxit PDF Document
二、 开关电源的概念 开关电源就是用通过电路控制开关管进行 高速的导通与截止．将直流电转换为高频率的交 流电提供给变压器进行变压，从而产生所需要的 一组或多组电压的电源。 1、开关电源主要有以下特点： （1）.体积小、重量轻：由于没有工频变压器， 所以体积和重量只有线性电源的20～30%。 （2）.功耗小、效率高：功率晶体管工作在开关 状态，所以晶体管上的功耗小，转 化效率高， 一般为60～70%，而线性电电源只有30～40%。
五、我们公司的AC-DC产品
产品型号 SP3706 SP3842 SP3843 SP7500 TL494 VIPER22A HT202 HT203 HT2262 HT2263 HT2268 HT2269 功能 PWM PWM PWM PWM PWM PWM+MOSFET PWM+三级管 PWM+三级管 PWM PWM PWM PWM Vin(AC) 85-264V 85-264V 85-264V 85-264V 85-264V 85-264V 85-264V 85-264V 85-264V 85-264V 85-264V 85-264V Vdd 4.8-5.3V 10－30V 10-30V 7-40V 7-40V 9-38V 4.8-9V 4.8-10V 11-30V 11-30V 12-23V 12-23V 启动电流 70uA 0.5mA 0.5mA 1mA 2.4mA 2.4mA 3uA 3uA 6.5uA 6.5uA 输出最大电 振荡频率 流/功率 10W 1A 1A 200mA 200mA 20W 5W 18W 30W 30W 100W 100W Adaptive 500KHz 500KHz 300KHz 300KHz 60KHz 66KHz 66KHz 65KHz 65KHz 65KHz 65KHz 封装 SOIC-8 SOIC-8 DIP8 SOIC-8 DIP8 SOIC-16 DIP-16 SOIC-16 DIP-16 DIP-8 DIP-8 DIP-8 SOT23-6 SOT23-6 SOIC-8 DIP8 SOIC-8 DIP8 备注
电机驱动LM298课件
步进电机驱动实例
总结词
精确控制，适用于需要高精度定位的场合。
详细描述
步进电机是一种通过脉冲信号控制的电机，能够实现精确的定位和速度控制。使用LM298驱动步进电机时，可以 通过控制脉冲信号的频率和数量来实现电机的转动角度和速度。这种控制方式适用于需要高精度定位的场合，如 数控机床、打印机等。
伺服电机驱动实例
电机。
通过PWM（脉冲宽度调制）控 制信号，LM298可以调节电机
的转速和方向。
LM298内置保护功能，如过流 保护和过热保护，能够提高系统
的稳定性和安全性。
LM298的优势与局限性
01
优势
02
高电压、大电流输出能力，适用于驱动多种类 型的电机。
03
内置保护功能，提高系统安全性。
LM298的优势与局限性
问题2
电机转动方向不对。解决方案：检查 输入信号的相位是否正确，可以通过 调整输入信号的顺序来改变电机的转 动方向。
05
电机驱动LM298的应用实 例
直流电机驱动实例
总结词
简单易用，适用于小型直流电机驱动。
详细描述
LM298是一款常见的电机驱动芯片，常用于直流电机驱动。它具有简单的控制方 式，只需通过PWM信号调节电机速度，同时支持正反转控制。由于其简单易用 ，广泛应用于小型直流电机驱动，如玩具车、无人机等。
连接方式
LM298的电源引脚应连接到适当的电 源，通常为直流电源。同时，输入和 输出引脚应连接到相应的电路中，以 实现电机的驱动和控制。
调试步骤与注意事项
调试步骤
首先，检查LM298的电源是否正常，确保电源电压在规定范围内。然后，检查 输入和输出引脚的信号是否正常，可以使用示波器或逻辑分析仪进行检测。
常用ADDA芯片的使用：并行ADC0809、串行ADC0832、串行PCF8591
⑶ 延时等待方式
工作在延时等待方式时,0809 EOC端可不必与80C51相连 端可不必与80C51相连, 工作在延时等待方式时,0809 EOC端可不必与80C51相连,是根 据时钟频率计算出A/D转换时间,略微延长后直接读A/D转换值。 A/D转换时间 A/D转换值 据时钟频率计算出A/D转换时间,略微延长后直接读A/D转换值。 14】 20中 EOC端开路 fosc=6MHz， 端开路， 【例9-14】 图9-20中，0809 EOC端开路，fosc=6MHz，试用延 时等待方式编制程序， 路模拟信号依次A/D转换一次， A/D转换一次 时等待方式编制程序，对8路模拟信号依次A/D转换一次，并把 结果存入以50H为首址的内RAM 50H为首址的内RAM中 结果存入以50H为首址的内RAM中。 编程如下： 解：编程如下：
ORG LJMP ORG LJMP ORG STAT: MOV MOV SETB SETB SETB MOV MOVX LJMP 0000H STAT 0013H PINT1 0100H R1,#30H R7,#8 IT1 EX1 EA DPTR,#0FEF8H @DPTR,A MAIN ;复位地址 ;转初始化程序 ;中断服务子程序入口地址 中断,转中断服务子程序; ;中断,转中断服务子程序; ;初始化程序首地址 ;置数据区首址 ;置通道数 ;置边沿触发方式 ;开中 ;CPU开中 ;CPU开中 0809通道 通道0 ;置0809通道0地址 启动0通道A/D ;启动0通道A/D 转主程序,并等待A/D A/D中断 ;转主程序,并等待A/D中断
⑵ 查询方式
工作在查询方式时,0809 EOC端可不必通过反相器与或相连 端可不必通过反相器与或相连， 工作在查询方式时,0809 EOC端可不必通过反相器与或相连， 直接与80C51 P1口或P3口中任一端线相连 口或P3口中任一端线相连。 直接与80C51 P1口或P3口中任一端线相连。 13】 20中 P1.0直接与 直接与0809 EOC端相连 端相连， 【例9-13】 图9-20中，用P1.0直接与0809 EOC端相连，试用查 询方式编制程序， 路模拟信号依次A/D转换一次， A/D转换一次 询方式编制程序，对8路模拟信号依次A/D转换一次，并把结果 存入以40H为首址的内RAM 40H为首址的内RAM中 存入以40H为首址的内RAM中。 解：
凌特选型高集成电源芯片使用介绍
TEMP
（J6）：
温度监视器。
输出电压调节方式
Output voltage regulation mode
调节输出电压的方式是改变电阻的阻值进行调节，在VFB 引脚与地之间增设一个电阻器RFB，可设置输出电压
输出电压公式：
VOUT=0.6V*(60.4K+RFB)/RFB
LTM4650 50a0.95v uses an instance
PIN 介绍
The PIN is introduced
（F5、F9）：
运行控制引脚。当RUN引脚上的电压 高于1.25V时，将开启模块中的每个通 道。当RUN引脚上的电压低于1.25V时， 将关闭相关的通道。
RUN1、 RUN2
（F8）：
内部远端采样放大器输出。 把该引脚连接至VOUTS1或 VOUTS2。在并联操作中， 把 其 中 一 个 VOUTS 引脚 接 至DIFFOUT即可。
LTM4650的50A0.95V使用实例
原理图设计详解
Schematic diagram design details
输入VIN管脚的 设计
输出管脚VOUT
在手册中的建议是每个通 道需要两个22uF输入陶瓷 电容抑制纹波电流，大容 量电容输入推荐的是 150uF额定电压为25V。所 以在本次VIN管脚接入了4 个22uF的瓷片电容，一个 大容量电容输入推荐的是 150uF。
原理图设计详解
Schematic diagram design details
VFB1、VFB2
电压跟踪信号 TRACK1、TRACK2
COMP1和 COMP2
SGND、GND、 SW
VFB1、VFB2是调节两个 输出电压的管脚，调节方 式是使用电阻调节，上文 中已描述，在多相操作中 把VFB引脚连接在一起可 实现并联运作。在本次设 计中两个管脚并联之后连 接一个103.5K欧姆的电阻 接至地端。
电源基础知识介绍ppt课件
原边过温保护（OTP）
保护模块工作于一定的温度范围内，自身保护的一种
原边欠压保护（UVP）
自我保护的一种，同时也是保证系统正常工作的一种电路
原边限流保护（OCP）
模块自身的保护，保护在副边电路发生故障时，不使故障扩大
副边过压保护（OVP）
保护用户电路在模块发生故障时不会损坏
线性电源
8、线性电压调整器的设计考虑因素： 压差 输出电流 损耗功率 输入电压范围
线性电源
9、线性电压调整器的设计实例
开关电源
开关电源
定义：利用功率半导体器件使变压器工作在高频开关状态 （饱和导通或截止），利用L、C储能并通过PWM控制获得 需要的电压的装置。
1、开关电源的缺点与优点
及续流二极管承受过大电流。
Is Vo 2 VsR
开关电源
Boost升压变换器
Vin
L
D
Vo
S
C
R
稳态输入/输出关系
V0
1 V in
1 d
(0 < d < 1)
开关电源
Boost 电路的特点 1） 输入电流纹波小，输出电流纹波大。开关管、
二极管的电流总是脉动的。过大的电压、电流 应力容易损坏器件。 2）连续方式下，纹波电流随电感的增大而变小。 3）在BOOST电路中，不能空载，否则输出电压 很高，有可能损伤电路中器件。
开关电源
13、电源模块应用主要参数：
输入电压范围：48V 36出电压范围：额定±1％
输出额定电流：应用中超过该额定值，输出电压跌落，通常 模块设计中会有一定的裕度。
开关电源
9、非隔离DC/DC开关电源实例
BUCK型开关电源
MAX485典型电路ppt课件
第9章 串行接口技术 4）写操作
下面以MAX485为例来介绍RS－485串行接口的应用。MAX485
的封装有DIP、SO和uMAX三种，其中DIP封装的管脚如图9.1所示。
管脚的功能如下：
RO：接收器输出端。若A比B大200mV，RO为高；反之为低电平。
RE：接收器输出使能端。RE为低时，RO有效；为高时，RO呈高阻
状态。
DE：驱动器输出使能端。若DE＝1，驱动器输
第9章 串行接口技术
(2)发送应答位和非应答位子程序
IIC总线上的第9个时钟对应于应答位，相应数据线上“0” 为“ACK”和“1”为“”。发送应答位和非应答位的子程序 分别如下。
①发送应答位ACK MACK： CLR SDA
SETB SCL NOP NOP CLR SCL SETB SDA RET
该子程序的入口条件是待发送的字节位于累加器ACC中。
WRB： MOV R7，#8 WLP： RLC A ；欲发送位移入C JC WR1 ；此位为1，转WR1 CLR SDA ；此位为0，发送0
SETB SCL
NOP
NOP
CLR SCL DJNZ R7，WLP ；未发完8位，转WLP
RET
；8位已发完，返回
9.2.3 典型IIC串行存储器的扩展 9.2.3.1 串行IIC总线EEPROM AT24CXX的扩展
1）基本原理 AT24CXX的特点是：单电源供电，工作电压范围宽1.8V～5.5V；低功耗 CMOS技术(100KHz(2.5 V)和400KHz(5V)兼容)，自定时写周期(包含自动 擦除)、页面写周期的典型值为2ms，具有硬件写保护。
第9章 串行接口技术
②控制字节的第5～7位为1～8片的片选或存贮器内的块地址选择位。此 三个控制位用于选片或者内部块选择。标准的IIC规程允许选择16K位的 存贮器。通过对几片器件或一个器件内的几个块的存取，可完成对16K 位存贮器的选择，如表9-6所示。
芯片 ppt课件
具有三态缓冲功能，这样才可以和数据总线相连)。 ❖ 锁存器扩展输出口（锁存器： 74LS273、74LS373、
74LS377等） ❖ 输出接口的主要功能：进行数据的保持（数据锁存）。
00
方式1:A、B口基本I/O；C口输入
11
方式2:A、B口基本I/O；C口输出
01
方式3:A口选通I/O；B口基本I/O
10
方式4:A、B口选通I/O
A口 0:禁止中断 B口 1:允许中断
计数器 方式
00:空操作 01:停止计数 10:计满后停止 11:开始计数
8155的命令字格式
D7 D6 D5 D4 D3 DD32 D2D1 DD01 D0 TM2 TM1 IEB IEA PC2 PCP2C1 PCP1B PAPB PA
PC0 PC1 PC2 PC3 PC4 PC5
37 38 39 1 2 5
芯片引脚功能：
三态地址/数据 复用线
地址锁存线
RAM及IO选择
CPU
复位端
读选通信号线 写选通信号线
片选线
AD0
PA0
AD1
PA1
AD2
PA2
AD3 AD4 AADD56 AD7
PA3 PA4 PPAA56 PA7
PB0
ALE
概述
一、I/O 系统的组成
I/O 系统
I/O 设备
输入：键盘、磁盘、光盘、扫描仪 … 输出：显示、打印机、笔绘仪、磁盘 …
I/O 接口：8155、8255、8253、8251、8279 …
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在LM317和LM337的使用过程中需要注意以下问题：
⑴当输出功率过大时应加散热片，以免烧毁芯片。
⑵芯片的in和out间的压差不能超过35V，
⑶芯片使用时,如果R2并联一个电容,可以大幅提高抵 抗谐波的能力.并联一个电容的同时,应该多加一个二 极管,使得电容放电时,保护芯片不受损坏。
3、LM2940
LM2940的典型应用电路如下所示：
当稳压芯片离电源滤波电路较远时应当加输入电容 C1。
输出电容Cout必须大于22uF，并且尽可能的靠近 稳压芯片，以减少干扰。
4、AMS1117
AMS1117是一款低压差的线性稳压器，当输出 1A电流时，输入输出的电压差典型值仅为 1.2V。 AMS1117除了能提供多种固定电压版本外 （Vout＝1.8V,2.5V,2.85V,3.3V,5V），还提供 可调端输出版本，该版本能提供的输出电压范 围为1.25V~13.8V。 AMS1117提供完善的过流保护和过热保护功能， 确保芯片和电源系统的稳定性。
Vout=1.25V（1+R2/R1）+Iadj*R2，但由于Iadj较小， 通常情况下可忽略不计。
LM337的典型应用电路如下图所示：
芯片的输出电压由R1和R2的比值决定，当固定R1 为120Ω时，其输出电压可由以下公式得出：
Vout=-1.25V*(1+R2/R1).当输入滤波电路离芯片的 距离超过10cm时需加输入电容Cin.
⑵当需要一个能输出1.5A以上电流的稳压电源时， 通常采用几块三端稳压电路并联起来，使其最大输 出电流为N个1.5A，但应使用同一厂家、同一批次 的产品。
⑶78/79系列的稳压集成块的极限输入电压是36V， 最低输入电压为输出电压的3-4V以上。
2、LM317、LM337
LM317L 三端正可调1.2V to 37V稳压器(0.1A) LM317T 三端正可调1.2V to 37V稳压器(1.5A) LM337K 三端可调-1.2V to -37V稳压器(1.5A) LM337T 三端可调-1.2V to -37V稳压器(1.5A) LM337L 三端可调-1.2V to -37V稳压器(0.1A)
1、78xx、79xx系列
78LXX 78MXX 78XX 79LXX 79MXX 79XX
正XXV稳压器(100mA) 正XXV稳压器(500mA) 正XXV稳压器(1.5A) 负XXV稳压器(100mA) 负XXV稳压器(500mA) 负XXV稳压器(1.5A)
78/79系列三端稳压芯片组成稳压电源所需的外围元件 极少，电路内部还有过流、过热及调整管的保护电路 ，使用起来可靠、方便，而且价格便宜。该系列集成 稳压IC型号中的78或79后面的数字代表该三端集成稳 压电路的输出电压。
LM2940CT-5.0 LM2940CT-8.0 LM2940CT-9.0 LM2940CT-10 LM2940CT-12 LM2940CT-15
5.0V低压差稳压器 8.0V低压差稳压器 9.0V低压差稳压器 10V低压差稳压器 12V低压差稳压器 15V低压差稳压器
பைடு நூலகம்
LM2940是输出电压固定的低压差三端稳压器， 输出电流1A；输出电流1A时，最小输入输出电 压差小于0.8V，能达到0.5V；当输出电流为 100mA时，最小压差为0.1V。最大输入电压 26V；工作温度-40～+125℃；内含静态电流降 低电路、电流限制、过热保护、电池反接和反 插入保护电路。常用封装如下图所示：
2、开关稳压电源
开关电源是指用于电压调整的管子工作在饱和和 截止区，即开关状态。 ⑴输出纹波较线性电源要大, ⑵结构简单,成本低, ⑶效率高(市面上的开关电源的效率也可达 90%以上)在很多场合已经替代了线性电源,是 未来电源发展的趋势。
二、常用线性稳压芯片
常用的线性稳压芯片有： 78XX、79XX LM317、LM337 LM2940 AMS1117 TPS7350 LT1764 MC34063
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10
LM317和LM337的使用非常简单，仅需两个外接电 阻来设置输出电压。此外它的线性调整率和负载调 整率也比标准的固定稳压器好。常用封装有SO-8和 TO-92，如下图所示：
LM317典型应用电路如下图所示：
其中Cin和Cout是两个滤波电容，通过改变R1和R2的 比率就可以改变输出端的电压。
LM317 和LM337的输出电压范围均是1.2V 至37V， LM317负载电流最大为1.5A。LM337负载电流最 大为 0.4~2.2A。内置有过载保护、安全区保护等 多种保护电路。通常LM317 和LM337不需要外接 电容，除非输入滤波电路到芯片输入端的连线超 过6 英寸（约 15 厘米）。
在78/79系列三端稳压器中最常应用的是TO-220 和 TO-202 两种封装。这两种封装的图形以及引脚序号、 引脚功能如附图所示:
78/79系列集成稳压器的典型应用电路如下图所示
实际应用注意事项：
⑴实际应用时应在三端集成稳压芯片上安装足够大 的散热器（小功率的条件下不用），当稳压管温度 过高时，稳压性能将变差，甚至损坏。
常用电源芯片的使用
一、常用电源芯片分类
根据调整管的工作状态，我们常把稳压电源分成两类：
1、线性稳压电源
电压反馈电路工作在线性(放大)状态，线性稳压直流电源的特 点是： ⑴输出电压比输入电压低； ⑵反应速度快，输出纹波较小； ⑶工作产生的噪声低； ⑷效率较低（现在经常看的LDO就是为了解决效率问题 而出 现的）； ⑸发热量大（尤其是大功率电源），间接地给系统增加热噪 声
AMS1117的典型应用电路如下所示：
使用说明： ⑴对于所有应用电路均推荐使用输入旁路电容C1为10uF钽电容。 ⑵为保证电路的稳定性，在输出端接22uF钽电容C2。 ⑶若想进一步提高纹波抑制比可考虑使用可调电压版本，并在可调
端接旁路电容CAdj，推荐使用10uF左右的钽电容。22uF的输出 电容基本可以满足在所有工作条件下，电路正常工作。CAdj值的 选取满足2*Fripple*CAdj<R1