Programmable dc-dc converter for active-matrix OLEDs

Diodes is aiming at active matrix OLED panels with three-output power management dc-dc converter.

Diodes AL3565 oled dcdc

Running from 2.9 to 4.8V, AL3565 produces:

  • 4.6 to 5.0V (VPOS) with 0.5% accuracy at up to 500mA from a buck-boost converter
  • -1.4 to -5.4V (VNEG) with 0.5% accuracy at up to 500mA from an inverting buck-boost converter
  • 5.8 to 7.9V (AVDD) with 0.5% accuracy at up to 100mA from a boost converter

A single pad programs the VPOS and VNEG output voltages in steps of 100mV, as well as AVDD in steps of 300mV.


Depending on this pad, the outputs default to: 4.6V, -2.5 or -4.0V and 6.1 or 6.4V at power-up.


Diodes AL3565 oled dcdc

“Once the device is enabled, AL3565 starts with its default values,” said Diodes. “The interface counts the rising edges applied to the pad and sets
the new values.”

When programmability is not required, the same pad can act as a standard enable pad and,

Soft-start limits in-rush currents, and the output rails rise in sequence: AVDD, VPOS, VNEG.

Another input controls whether or not the outputs are fast-discharged when the device is disabled.

Protections include short-circuit and thermal shut-down when its junction exceeds +150°C (typ) – it automatically re-starts when the junction gets back down to +140°C typ.

Operation is over -40 to + 85°C, and packaging is 3 x 3mm 16pad QFN3030 with an exposed pad, although WL-CSP is among special-order options.

Steve Bush

Steve Bush is the long-standing technology editor for Electronics Weekly, covering electronics developments for more than 25 years. He has a particular interest in the Power and Embedded areas of the industry. He also writes for the Engineer In Wonderland blog, covering 3D printing, CNC machines and miscellaneous other engineering matters.

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