On-chip DC/DC converter powers digital isolators

The isolators include a DC/DC controller with user-adjustable frequency for minimising emissions, a soft-start function for safety, a shutdown option, and loop compensation. The Si88x2x modules’ topology allows them to sense the output voltage on the secondary side without requiring additional optocouplers and support circuitry to bias those optocouplers. This allows the DC-DC converter to operate with excellent line and load regulation while reducing external components and increasing lifetime reliability.

The DC-DC converter works in conjunction with an external transformer to provide up to 5W of isolated power with a 24V input supply and an external switch to supply the secondary side of the Si88xx2x, as well as other circuits on the isolated side with a 5V supply.

The ultra-low-power digital isolation channels offer substantial data rate, propagation delay, size, and reliability advantages over legacy isolation technologies. Data rates up to 100Mbps are supported, and all devices achieve propagation delays of only 23ns (max).

The Silicon Labs Si886xxISO-EVB Evaluation Kit, also available from Mouser Electronics, demonstrates the digital isolation capabilities of the installed Si88621ED-IS and its DC-DC converter performance.

Convenient test points are included to measure and observe time varying currents and voltages to calculate relevant parameters like efficiency and load/line regulation.

The AEC-Q100-qualified and RoHS-compliant Silicon Labs Si88x2x Dual Digital Isolators are ideal for power supply, electric vehicle, industrial, and motor control applications.