TPS6102x

      The TPS6102x has features including 96% Efficient Synchronous Boost Converter,200-mA Output Current From 0.9-V Input,500-mA Output Current From 1.8-V Input;Output Voltage Remains Regulated When Input Voltage Exceeds Nominal Output Voltage;Device Quiescent Current: 25-A (Typ);Input Voltage Range: 0.9-V to 6.5-V.
      The TPS6102x devices provide a power supply solution for products powered by either a one-cell,two-cell, or three-cell alkaline, NiCd or NiMH, or one-cell Li-Ion or Li-polymer battery. Output currents can go as high as 200 mA while using a single-cell alkaline, and discharge it down to 0.9 V. TPS6102x can also be used for generating 5 V at 500 mA from a 3.3-V rail or a Li-Ion battery. The boost converter is based on a fixed frequency, pulse-width-modulation (PWM) controller using a synchronous rectifier to obtain maximum efficiency. At low load currents the converter enters the Power Save mode to maintain a  high efficiency over a wide load current range.The TPS6102x devices keep the output voltage regulated even when the input voltage exceeds the nominal output voltage. The output voltage can be programmed by an external resistor divider, or is fixed internally on the chip. The converter can be disabled to minimize battery drain. During shutdown, the load is completely disconnected from the battery.A low-EMI mode is implemented to reduce ringing and, in effect, lower radiated electromagnetic energy when the converter enters the discontinuous conduction mode. The TPS6102x is packaged in a 10-pin QFN PowerPAD™package measuring 3 mm x 3 mm (DRC).
      Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating conditions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.The controller circuit of the TPS6102x is based on a fixed frequency multiple feedforward controller topology. Input voltage, output voltage, and voltage drop on the NMOS switch are monitored and forwarded to the regulator. So changes in the operating conditions of the converter directly affect the duty cycle and must not take the indirect and slow way through the control loop and the error amplifier. The control loop, determined by the error amplifier, only has to handle small signal errors. The input for it is the feedback voltage on the FB pin or, at fixed output voltage versions, the voltage on the internal resistor divider. TPS6102x is compared with the internal reference voltage to generate an accurate and stable output voltage.