UC1875 family

      This is the description of UC1875 family: The UC1875 family of integrated circuits implements control of a bridge power stage by phase-shifting the switching of one half-bridge with respect to the other, allowing constant frequency pulse-width modulation in combination with resonant, zero-voltage switching for high efficiency performance at high frequencies. This family of circuits may be configured to provide control in either voltage or current mode operation, with a separate over-current shutdown for fast fault protection. A programmable time delay is provided to insert a dead-time at the turn-on of each output stage. This delay, providing time to allow the resonant switching action, is independently controllable for each output pair (A-B, C-D). With the oscillator capable of operation at frequencies in excess of 2MHz, overall switching frequencies to 1MHz are practical. In addition to the standard free running mode, with the CLOCKSYNC pin, the user may configure these devices to accept an external clock synchronization signal, or may lock together up to 5 units with the operational frequency determined by the fastest device. Protective features include an undervoltage lockout which maintains all outputs in an active-low state until the supply reaches a 10.75V threshold. 1.5V hysteresis is built in for reliable, boot-strapped chip supply. Over-current protection is provided, and will latch the outputs in the OFF state within 70nsec of a fault. The current-fault circuitry implements full-cycle restart operation. Additional features include an error amplifier with bandwidth in excess of 7MHz, a 5V reference, provisions for soft-starting, and flexible ramp generation and slope compensation circuitry.
      And these are the features of UC1875 family : Zero to 100% Duty Cycle Control; Programmable Output Turn-On Delay; Compatible with Voltage or Current; Mode Topologies; Practical Operation at Switching Frequencies to 1MHz; Four 2A Totem Pole Outputs; 10MHz Error Amplifier; Under voltage Lockout; Low Startup Current 150 A; Outputs Active Low During UVLO; Soft-Start Control; Latched Over-Current Comparator; with Full Cycle Restart; Trimmed Reference.
      And these are the absolute maximum ratings of UC1875 family: Supply Voltage (VC, VIN) is 20V; Output Current, Source or Sink DC is 0.5A and Pulse (0.5 s) is 3A; Analog I/0s (Pins 1, 2, 3, 4, 5, 6, 7, 15, 16, 17, 18, 19) is from 0.3 to 5.3V; Storage Temperature Range is from65°C to +150°C; Junction Temperature is from 55°C to +150°C; Lead Temperature (Soldering, 10 sec.) is +300°C.