Watch a demonstration of the ZL8801 four phase digital DC/DC controller demo board.


Hello. My name is Brandon Howell, I handle technical marketing with Renesas' Digital Power Group. I'm here to discuss the ZL8801, specifically our four-phase demo board. So here is our ZL8801 four-phase demo board. It consists of two ZL8801 controllers, our DrMOS power supplies, there's four of those, one for each phase, our output inductors then also our output capacitance. On the board we've got headers for the input voltage, this is for the output voltage. I've got the output voltage connected to an electronic load. And then we have our USB to PMBus dongle. This allows the board to interface with a windows PC right in our PowerNavigator software. The ZL8801 is a fully digital controller, because of that there's very little components around the controller itself. We have some decoupling capacitors, a few resisters to set the output voltage and the PMBus address, but really that's it. Everything else is adjusted inside the device using digital registers and then stored using our non-volatile memory. So that's a quick overview of the board and let's jump into PowerNavigator software and talk to the board, and look at the load, the output voltage etc.

Now let's launch PowerNavigator and start communicating with this ZL8801 four-phase eval board. So again, once the PowerNavigator launches, it automatically scans the PMBus using the dongle. And we've discovered two ZL8801 controllers, both on this eval board. One's at address 20 the other's at address 21. So I'm gonna go ahead and launch the software. As I click the start button, the tool automatically goes out, downloads all the configuration settings from the device. And now I'm talking to the eval board directly. So, PowerNavigator has a power map, that shows the controller. It has a Monitor View that shows the output voltage, the current, the input voltage, the voltage monitor. I can also expand on this, and actually show individual phases. So the panel on the left shows the total load current, the output voltage, and the input voltage of course is the same. And then the two panels on the right here show the load current per controller. So once I enable the output, you can actually look in real time and see what the current balance is between the controllers as everything is running.

So I'm gonna go ahead and turn on the output. I actually have an electric load connected to this board right now. The load is set for approximately 22A. So I'm actually sourcing 22A from the eval board. The board itself is showing an output current of 22A, and the current balance between controllers is very good within about, half an amp. So I've got about ten, ten and a half amps per controller being supplied to the load. Using the GUI, I can turn the output voltages off, I can turn the output voltages down, so I will margin high. When I margin high, in this case I have set the margin to 1.3V, I can margin back to the nominal voltage, I can margin low. In this case I set the margin low voltage to 1.1V. And then again I can margin back to nominal. I can also change the output voltage into real time, to something else besides the preset margins. So, for example, if I wanna go at 1.25V, I can type in 1.25V, I hit the return key, and the output automatically goes to 1.25V. So, it is a nice feature, even though the controllers are in current share, I can still change the output voltage dynamically with the VOUT commands. When I turn the load current off, the load goes away, and now we're in a no load situation. I can also disable the output using the GUI, very easy to evaluate the eval board with.