Our popular VIM3 single board computer with the Amlogic A311D SoC and 5.0 TOPS NPU has been updated from v13 to v14!
The TPS2121RUXR chip used in the v13 has been replaced with the WS4684C in v14 as the original chip that controls the power source selection between USB-C and VIN is in short supply. Find out what's changed in this blog post.
Updated Power Supply Design
1. Schematics:
A new circuit diagram showing the changed between TPS2121RUXR and WS4684C.
2. Circuit Description:
a) The TPS2121RUXR chip used in the v13 has been replaced with the WS4684C in v14 as the new power management chip.
b) DCIN, which provides electrical power, is the unified power supply for the entire system.
c) DCIN_USBC and DCIN_VIN are two paths to supply power to DCIN. DCIN then supplies power to the VIM3. Both DCIN_USBC and DCIN_VIN are in a high-impedance state when there is no power input:
The DCIN_USBC transmit power via the USB-C port of VIM3.
The DCIN_VIN transmit power via the VIN port on the back of the VIM3.
d) The power supply priority of DCIN_VIN is higher than that of DCIN_USBC. This means that if electrical power is supplied to both the USB-C and VIN ports simultaneously, VIM3 will choose to use power from the VIN port.
e) When the power supply switches from DCIN_USBC to DCIN_VIN, that is, when the VIM3 is powered via the USB-C port and the VIN port is then simultaneously connected, the power supply will switch to the VIN port. When this happens, the WS4684C will incur a 22ms switching delay, and this will cause VIM3 v14 to restart.
3. WS4684C Power Switching Logic Table:
USB-C Port (Net: DCIN_USBC) | VIN Connector (Net: DCIN_VIN) | Power Selection (DCIN) |
ON | OFF | USB-C |
OF | ON | VIN |
ON | ON | VIN |
New PCB Layout
1. PCB 2D Layout
2. PCBA Photograph
3. Possible Risk
When the VIM3 v14 is powered via the USB-C port, and then power is also supplied to the VIN port, then VIM3 v14 will switch over to the VIN power supply, causing the device to restart.
When will v14 be in stock?
Presently, all VIM3 boards purchased from Khadas Shop, AliExpress and Amazon are guaranteed to be the v14 version. The new boards are available now!
To improve your productivity and satisfaction is always in our first priority. If you have any questions on the VIM3 update, please feel free to contact us at support@khadas.com :p
Links & References:
Warmly,
Khadas Maker Team
