When using a triple output power supply, it can sometimes be risky to simple turn on all
the outputs.
A lot of devices need to be powered up in a very specific order – or you could damage
them.
Today, we’re going to look at a way to protect your device using a power supply mode called sequencing
Hi I’m Daniel Bogdanoff, and I’m here with Bill Griffith on of our Power Supply
folks here at Keysight.
Many devices or models require multiple bias or rail voltages, and devices such as an FPGA
require the voltages to turn on and off in a set sequence.
If you’re working with devices that have specific timing requirements, you’ll want
to use a power supply with power sequencing.
Thanks for having me!
Power supply sequencing allows you to automatically set voltage outputs and delays according to
a pre-scripted pattern of your choosing.
This means you won’t have to manually turn on different channels or manually set output
voltages – helping you avoid accidental damage.
So, let’s look at how to set up power sequencing – we’re going to use the E36312A, if you’re
using a different supply your menus will look different.
Also, instead of powering up an FPGA or board – we’re going to use these lights Bill
brought with him, so it’ll be obvious when power is applied.
The first step is to set up each output for the correct voltage and current limit.
This power supply’s three outputs are all independent and isolated, so it’s easy to
set the voltages and not worry about having a common ground.
Once we’ve done that, it’s time to set our delays.
I’ll Configure the “On Delay” and “Off Delay” for each channel.
The on delay is how long it waits to turn on after you start the sequence, and the off
delay is how long it waits once you initiate the end of the sequence.
The delays can be set with millisecond resolution but realize the power outputs take 10 to 50
ms to reach their programmed voltage.
We’re using rather long delays, so we can see each output turn-on and then off.
Now that everything’s setup, we’re ready to connect to our light and start our sequence.
I’ll press the “on all” button.
You can see the outputs turn on with their respective delays.
Likewise, you can turn off all the outputs and see the turnoff delays.
Some device can be damaged if they are not powered down in the correct order.
What if you need more than three voltages?
You can couple and sync multiple supplies together using the digital I/O ports on the
back.
Once we’re physically connected to the IO pins, we have to configure the digital IO
port.
The digital IO port can be used for many different tasks.
I will configure Pins 2 and 3 of both supplies to be set to “on couple” and “off couple”.
Fun UI fact that Bill taught me, the “meter view” button acts as a home button and is
an easy way to exit out of any menu tree.
With the digital IO configured we will setup the coupling on the first power supply.
On the second power supply, we select the outputs to be enabled upon receiving the signal.
I’ll choose two channels.
We can also set the output delays from this same screen.
Lastly, we need to check the output voltage and current limit on each output – not checking
is a good way to damage a device.
Now let’s put it all together.
To start it up, we push the “On-all” button.
When sequencing is setup, the on-all button will start up the sequence.
When you’re done, you can hit the same button to start the off sequence.
Right, all the outputs will turn off in our predefined sequence.
So, a quick recap, some devices require sequencing to be properly powered on and off.
For tests requiring a larger number of channels, power supplies can be coupled together.
I find that I can often borrow a second or third power supply for a test and promptly
return them as it takes very little time to setup the additional power supplies.