While searching around for regulators to convert my new scope to 12v power, I remembered I had some DC-DC modules from Texas Instruments that I’d got a while ago. Luckily a couple of these are inverting controllers, that will go down to -15v DC at 15W/3A capacity.
I’ve had to order a new module from TI to do the -17v rail, but in the meantime I’ve been getting the other regulators set up & ready to go.
The DC-DC module I’ve got for the -7.5v rail is the PTN78060A type, and the +7.5v & +5v rails will be provided by the PTN78020W 6A buck regulators.
These regulators are rated well above what the scope actually draws, so I shouldn’t have any issues with power.
Here’s the regulators for the 5v, 7.5v & -7.5v rails, with multiturn potentiometers attached for setting the voltage output accurately. I’ve also attached a couple of electrolytics on the output for some more filtering. I’ll add on some more LC filters on the output to keep the noise down to an absolute minimum. These are set up ready with the exact same output voltage as the existing mains AC switching supply, when the final regulator arrives from TI I will put everything together & get some proper rail readings.
There won’t be a proper PCB for this, as I don’t have the parts in Eagle CAD, and I simply don’t have the energy to draw them out from the datasheets.
This is an old USB 1.1 hub that was recently retired from service on some servers. Top of the unit visible here.
Bottom label shows that this is a model F5U021 hub, a rather old unit.
PCB is here removed from the casing, Indicator LEDs along the bottom edge of the board, power supply is on the left. Connectors on the top edge are external power, USB host, & the 4 USB outputs. Yellow devices are polyswitch fuses for the 500mA at 5v each port must supply.
This is the USB Hub Controller IC, which is a Texas Instruments TUSB2046B device. Power filter capacitors next to the USB ports are visible here also, along with 2 of the polyswitches.
The power supply section of the unit, which supplies regulated 5v to the ports, while supplying regulated 3.3v to the hub controller IC. Large TO-220 IC is the 5v regulator. Smaller IC just under the power selector switch is the 3.3v regulator for the hub IC. The switch selects between Host powered or external power for the hub.
This is a device designed to reset Epson brand ink cartridges that are reportedly out of ink, so they again report full to the printer Here is the front of the unit, with the guide for attaching to a cartridge.
Back of the device removed. 3 button cells provide power to the PCB. Indicator LED sticks out of the top of the device for reset confirmation.
Row of pads on far left edge of the PCB are presumably a programming header for the uC on the other side of the board.
Here is the front of the PCB, main feature being the grid of pogo pins to connect to the cartridge chip. IC on lower right of that is a MSP430F2131 uController, a Texas Instruments part.
The IC directly to the left of the pogo pin bed is a voltage regulator, to step down the ~4.5v of the batteries down to the ~3.3v that the uC requires.