Power supply unit

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Power supply unit receives filtered output voltage from batteries and transforms it into required set of stable DC voltages. Its main purpose is to provide a wide spectrum of different voltages, transformed efficiently, and also provide enough power rails and current for any actual or future device. In this sense it is very similar to a power supply of a personal computer. However, this power supply unit is not designed to run robot's embedded computer, but only electronic schemes. Embedded computer is powered up from the one or several widely spread DC-DC ATX converters.

The input voltage range is 17V-28VDC.

There is a range of required output voltages:

Optional rails:

All of 1.8 VDC, 3.3 VDC, 5.0 VDC and 12.0 VDC - are high current rails, short circuit protected; Negative voltage lines -5.0 VDC and -12.0 VDC - are low current rails (up to 0.3A total per rail);


Version 2

Version 2 is planned and must come as close to the initial requirements as possible. Also there must be an option to manually disable each of the conversion rails, to reduce power consumption.

Schematic capture

PSU schematic capture. Version 2.0. This board is designed to provide high power output through multiple rails with different ratings.

PCB Layout

Two-sided PCB is shown below:

PCB of the PSU. This version is not copper-poured (but the final version is).

Device photo

Device photo of the PSU (copper-poured version). Copper pouring reduces ground rail resistance and improves frequency and thermal parameters of the board.


Preliminary ratings

Output rail voltage, VDC Max current, Amps Device name Description
12 10 Vicor V24C12T100BG (24V->12V) Total power: 100W. Vicor Brick DC-DC converter. Can be switched on with the jumper or by the external logic (CMOS-compatible).
5 10 Vicor VI-JW0-EY (24V->5V) Total power: 50W. Vicor Mini DC-DC converter. Can be switched on with the jumper or by the external logic (CMOS-compatible).
5 (external standby) 30 mA @ 24V input;
18 mA @ 40V input
LM2936 Total power: 600 mW. Linear regulation from input voltage 22.2V (18-27V) with LM2936 (linear regulator with low quiescent current). External standby can be switched ON with the jumper (default - jumper closed). Internal standby is always ON.
3.3 18 ACON DH50S24033 (24V->3.3V) Total power: 50W. Efficiently converted with integrated switched mode DC-DC from input voltage (range 18-36V). ACON DC-DC switched mode, single output 3.3V with trim. Can be switched on with the jumper or by the signal of external logic (CMOS-compatible).
1.8 8 PT6526L Total power: 14W. Converted with switched mode DC-DC converter. input voltage range 3.1-5.5V. Fed by the 3.3V power supply output rail. Can be switched on with the jumper or by the signal of the external logic (CMOS-compatible).
-5 0.1A LMC7660 (IC 5V->(-5V)) Total power: 1.2W. Efficiently converted from standby voltage source. Can be turned on by the jumper, but not externally controllable.

Tested ratings

Standby current

Output rail voltage, VDC Standby current, mA No load current, mA Device name Description
12 4mA 4.4-6.1 Watts Vicor V24C12T100BG (24V->12V)
5 6mA 1.35-2.0 Watts Vicor VI-JW0-EY (24V->5V)
5 (external standby) 15uA @ no load (100uA) 0.5mA @ 10mA + Iload LM2936 (IC 24V->5V)
3.3 30-50mA PT6601 (5V->3.3V)
1.8 15-25mA PT6526L (5V->1.8V)
-5 N/A 400uA LMC7660 (IC 5V->(-5V))


Parts list

Version 1

There is a first, preliminary, version of a Power Supply Unit.

Schematic capture

PSU schematic capture (original name is LP-PSU2). Version 1.0. This board is designed to provide low power output through multiple rails with different ratings.

PCB Layout

Device photo

A photo of the both sides of the Power Supply Unit (version 1) (original name is LP-PSU2). First pin is marked with blue and yellow dot.

It is capable to provide the following outputs:

However, since 24/3.3VDC converter lacks a ballast load, and because of its switching nature, there is some extra heating of converter's surface and increased energy consumption, even when it is not loaded.

Also, as appeared, this version is not mountable into the back capsule of the robot because of not properly placed mounting holes.

See also

Personal tools