47 kHz switching with a 50 % duty ceiling
The UCC2806M is a current-mode PWM controller from Texas Instruments, switching at 47 kHz with a hard 50 % maximum duty cycle. That duty limit is deliberate — it prevents transformer saturation in push-pull and half-bridge topologies where flux walking would otherwise accumulate over consecutive cycles. The 8 V to 14.5 V supply range powers the control logic and gate drive directly, so no external bias rail is needed for a typical off-line flyback or forward converter.
Topology flexibility — boost, flyback, forward
The controller supports boost, flyback, and forward converter topologies, with an output configuration that is positive and isolation-capable. Two transistor-driver outputs drive external MOSFETs in a master-slave or interleaved arrangement; the synchronous rectifier enable means the secondary-side SR FET can be driven in phase with the primary switch, reducing conduction loss in low-voltage outputs. Control features include current limit, an enable pin for sequencing, and frequency control — the oscillator frequency is set by an external RC network, so you can push or pull the 47 kHz nominal to suit the transformer core size and EMI filter corner. The 16-SSOP package (3.90 mm body width) fits a compact layout on a four-layer board; the 0.154-inch pitch is hand-solderable but benefits from a reflow profile matched to the MSL level on the reel label.
The device is ROHS3 Compliant, so it passes the EU RoHS exemption list without conflict.