EFM32WG Datasheet, PDF (241/834 Pages) List of Unclassifed Manufacturers – The EFM32WG Wonder Gecko is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive applications.

15.3.2.1 Bus-powered Device
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A bus-powered device configuration is shown in Figure 15.2 (p. 241) . In this configuration the voltage
regulator powers the PHY and the EFM32 at 3.3 V. The voltage regulator output (USB_VREGO) can
also be used to power other components of the system.
In this configuration, the VREGO sense circuit should be left disabled.
Figure 15.2. Bus-powered Device
VDD
EFM3 2
USB_VREGO
USB_VREGI
USB_VBUS
USB_DP
USB_DM
VBUS
D+
D-
GND
15.3.2.2 Self-powered Device
A self-powered device configuration is shown in Figure 15.3 (p. 241) . When the USB is configured as
a self-powered device, the voltage regulator is typically used to power the PHY only, although it may also
be used to power other 3.3 V components. When the USB is connected to a host, the voltage regulator is
activated. Software can detect this event by enabling the VREGO Sense High (VREGOSH) interrupt. The
PHY pins can then be enabled and USB traffic can start. The VREGO Sense Low (VREGOSL) interrupt
can be used to detect when VBUS voltage disappears (for example if the USB cable is unplugged).
In this configuration, the VREGO sense circuit must be enabled.
Figure 15.3. Self-powered Device
1.8V – 3.6V
VDD
EFM3 2
USB_VREGO
USB_VREGI
USB_VBUS
USB_DP
USB_DM
VBUS
D+
D-
GND
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
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