FPF1320 Power Multiplexer Carrier with USB Micro-B Connector

The FPF1320 dual-input single-output power switch is a unique IC that switches a load between two power sources. It behaves as a power multiplexer (or mux), using a digital select signal to determine which of the two 1.5 V to 5.5 V input power rails to connect to the output, and can handle a maximum of 1.5 A while blocking unwanted reverse current from flowing from output to input or between inputs. Each input channel is controlled by an internal MOSFET switch.

The board is configured so that the “B” power rail is preferred and will be selected by default when that power source is present. USB power is connected to this preferred rail, so the default behavior is for the board to select USB power when USB is connected and the alternate “A” power rail when it is not. This enables the common application of having a device that can be powered by USB or an external power supply, automatically choosing the appropriate source based on what is connected. The default behavior can be changed through a surface-mount jumper and overridden through the power select (SEL) input.

Power connections without USB:

If you want to select from between two general power supplies, you can connect one power source across VINA and GND and the other across VINB and GND. The voltages on these power inputs should be between 1.5 V and 5.5 V. The load should be connected across VOUT and GND and should draw no more than 1.5 A. In this configuration, the “B” power supply is preferred and connected to the output by default when it is present.

Power connections with USB:

The Micro-B USB connector makes it easy to use USB as one of the two power sources. By default, the VBUS line from the USB connector is tied to VINB. This allows you to power your circuit from either USB or an external power source connected to VINA, with USB as the preferred power source.

If you want the external source to be preferred instead of USB, you can use a hobby knife to cut the trace in the board’s surface-mount jumper that connects the VINB and VBUS pads, then bridge the VBUS and VINA pads to connect those two lines together. You can then connect your external source to VINB, making it the preferred supply.

Documents / Downloads:

• FPF1320 datasheet
• Schematic
• Dimension

Package includes:

• 1x FPF1320 Power Multiplexer Carrier with USB Micro-B Connector
• 1x 12Pin straight Male Header