DESCRIPTION

· The UCC3752 controller drives a power stage for low-frequency, high-voltage sinusoidal signals in telephone ringing applications.
· It is ideal for up to 5-line systems, emphasizing low cost, high efficiency, and minimal components.
· The ring generator operates in a non-isolated, open-loop manner with a semi-regulated DC voltage offset.
· It drives primary switches for a push-pull resonant converter and secondary sampling switches.
· Primary and secondary frequencies are offset to produce a high-voltage, low-frequency output.
· Off-hook detection is achieved by sensing AC current, triggering a flag on the OFFHOOK pin.
· Frequencies are derived from a 3.579545 MHz crystal, with primary switching at 89.489 kHz and sampling at 20, 25, or 50 Hz less based on FS0 and FS1 pins.

FEATURES

· Novel topology for cost-effective and efficient ring voltage generation.
· Suitable for multi-line operation.
· Selectable ring frequencies: 20, 25, and 50 Hz.
· Secondary (AC) current limiting for off-hook detection.
· Primary current limiting to disable the power stage under fault conditions.
· Operates from a single 12V supply.

APPLICATIONS

· Telephone ringing signal generation.
· Low-cost, high-efficiency multi-line systems.