Diode Selection

Diodes in wireless charging serve as output rectifiers, bootstrap clamps, snubber elements, and transient suppressors. Selection balances reverse voltage margin, average and surge current, forward drop, and reverse recovery charge Qrr.

Fast recovery diodes trade lower Qrr against higher forward drop — synchronous rectification removes output diodes but not all diode functions.

01Receiver rectifier diodes

• Schottky where voltage allows for low VF — watch leakage at hot temperature.
• Ultrafast silicon for higher voltage receiver outputs.
• Parallel diodes only with matched sharing layout — rarely preferred over single larger die.

02Clamp and snubber diodes

Must be rated for repetitive peak current in ringing networks. Soft recovery types sometimes reduce EMI at cost of snubber dissipation. Place close to the switch or transformer terminal they protect.

03Qualification

• Test reverse recovery under actual dI/dt from coil current, not datasheet alone.
• Thermal interface for rectifier heat sinking on compact AMR receivers.
• Spares catalog: diode failures often correlate with alignment abuse — log fleet events.