Digital Multiphase Controllers with PowerNavigator

Part 2: Control Loop
Added on October 26, 2016

Learn about full digital control loop and how easy it is to tune using the PowerNavigator GUI software. The patented Intersil synthetic current control technology achieves the industry's fasted transient response.

Video Transcript

This video highlights the full digital control loop in our latest generation, multiphase products. Renesas' multiphase products have a control loop called synthetic current control. It's a full digital control loop that's very easy to tune.

We are using the ISL68137 evaluation board to demonstrate. The eval board has a controller as well as our smart power stages. On the eval board is a 100A low transient generator with a DIDT of 100A/µs. On the oscilloscope, we have the output voltage, the load step, and two of the six PWM signals driving the power stage. With our default configurations, the output voltage is within plus minus 4% of the 1V set point.

Using the PowerNavigator™ GUI software, we will show how easy it is to dial in and improve the transient response with the synthetic current control loop. Moving to PowerNavigator, the first thing we'll show is increasing the gain of the control loop. There's a proportional gain term by increasing it with the GUI, and then going back to the transient response, you can see now, we've reduced the peak-to-peak deviation to plus minus 3%.

The next feature we'll show is called pulse advance. Pulse advance allows us to temporarily speed up the switching frequency during a load step. Currently, pulse advance is disabled. As we enable it and turn up the pulse advance gain, you can see now that the load step, the output voltage deviation is down to 2%.

On the load release side, synthetic current control has a feature called diode breaking. Diode breaking turns on the low-side MOSFET during a load release to improve the output voltage deviation during the load release. We'll go ahead and enable that. Now the output voltage deviation has decreased to plus 2%.

That wraps up our demonstration of synthetic current control. With Renesas' PowerNavigator GUI software, full digital control loop, and latest digital multiphase products, tuning the transient response for any type of load step is now very simple.