UC1861

The UC1861 is a kind of resonant-mode power supply controller. It is designed for the control of zero current switched and zero voltage switched quasi-resonant converters. The primary control blocks implemented include an error amplifier to compensate the overal system loop and to drive a voltage controlled oscillator (VCO).

There are some features of UC1861 as follows: (1)zero-crossing terminated one-shot timer; (2)precision 1% soft-started 5 V reference; (3)programmable restart delay following fault; (4)voltage-controlled oscillator (VCO) with programmable minimum and maximum frequencies from 10 kHz to 1 MHz; (5)low start-up current (150A typical); (6)dual 1 A peak FET drives; (7)UVLO option for off-line or DC/DC applications.

The following is about the absolute maximum ratings of UC1861: (1)VCC: 22 V; (2)output current: source or sink (pins 11 & 14): 0.5 A; DC pulse (0.5s): 1.5 A; (3)power ground voltage: ±0.2 V; (4)inputs (pins 2, 3, 10 & 15): -0.4 to 7 V; (5)error amp output current: ±2 mA; (6)power dissipation: 1 W; (7)junction temperature (operating): 150; (8)lead temperature (soldering, 10 sec): 300.