'Selector' related articles 1

  1. 2008/06/24 AAT4672 - Power Supply Selector Switch

General Description
The AAT4672 SmartSwitch™ is a member of AnalogicTech’s Application Specific Power Management IC™ family.
This device is a dual input, single output power supply selector switch, designed to operate from USB ports, AC adapter inputs, batteries, or any other power supply with an input voltage up to 6V.
The AAT4672 connects the supply on the MAIN pin to the OUT pin through a very low on-resistance power MOSFET when the device is enabled, the MAIN pin voltage is higher than the under voltage lockout (UVLO) threshold, and MAIN pin voltage is greater than the AUX pin voltage plus 200mV.
The AUX pin connects to the OUT pin only when the MAIN pin voltage drops 0.2V below the AUX pin voltage and the AUX pin voltage is greater than the UVLO threshold.
If both input supplies (MAIN/AUX) are below the UVLO threshold, then the OUT pin floats.
The two internal power switches are current limited and the thresholds can be programmed through resistors on the IMAIN and IAUX pins respectively.
A power level selection pin, PWRSEL, is provided to toggle the AUX current limit between 100% and 20% of the current limit setting programmed by the resistor on the IAUX pin.
This is particularly useful for USB applications where the power supply can be powered by either a 500mA or a 100mA USB port.
The AAT4672 is available in a thermally enhanced, space-saving, Pb-free 12-pin TSOPJW package and is specified for operation over the -40°C to +85°C temperature range.

* Input Voltage Supply Range: 2.5V to 6V
* High Level of Integration:
- Reverse Blocking Diode
- Current Sensing
- Programmable Current Limiting
- Automatic Power Supply Switching
* Break-Before-Make Switch-Over
- Minimum Output Voltage Drop During Change-Over
* Shutdown Current < 1μA
* Thermal Protection
* TSOPJW-12 Package

* Bluetooth™ Headsets
* Cell Phones
* Digital Still Cameras
* MP3 Players
* Personal Data Assistants (PDAs)


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