电池充电电路设计及关键考虑点.pdfVIP

Battery Charger Design: Key considerations and system design limitations 1 Agenda • Single Cell Charger Systems • Input Considerations and Limitations • Topology Options – Pros Cons of Power Path Architecture • Thermal Issues • Market Trends Needs vs. Limitations • Input Current Optimizer (ICO • Summary and Questions 2 Single Cell Systems Overview • Single Cell – Most Common Solution for Smartphones (1s) and Tablets (1sXp) today – Allows for simple, low voltage design on the system (Max Battery Voltage 4.35V on some lithium based chemistries) – Simple design to charge from a 5V supply as the charger will always operate in step down mode – Multiple cells in parallel allow for longer run times due to extra capacity • This will require a higher charge currents to maintain an acceptable charge time. Charge current will be a function of the current capability of the adapter. 1s configuration 1sXp configuration 3 Input Considerations • How many input connectors will the device have? – Single Input (i.e. Micro-USB, Proprietary Connector) – Multiple Inputs (i.e. Micro-USB and Dock Connector) • How many input sources will the product support? – USB charging only (Max current: 500mA for USB2.0, 900mA for USB3.0) – USB charging and/or adapter into single port • For Micro-USB port, maximum current Output current change based on input voltage (assume supported by adapter is 1.8A 90% effici