UC2824

www.ti.com UC1824 UC2824 UC3824 SLUS326A – MARCH 1997 – REVISED JULY 2007 HIGH SPEED PWM CONTROLLER FEATURES Complementary Outputs Practical Operation Switching Frequencies to 1 MHz 50-ns Propagation Delay to Output High Current Dual Totem Pole Outputs (1.5 A Peak) Wide Bandwidth Error Amplifier Fully Latched Logic With Double Pulse Suppression Pulse-by-Pulse Current Limiting Soft Start/Maximum Duty Cycle Control Under-Voltage Lockout with Hysteresis Low Start Up Current (1.1 mA) Trimmed Bandgap Reference (5.1 V ± 1%) DESCRIPTION The UC1824 family of PWM control devices is optimized for high frequency switched mode power supply applications. Particular care was given to minimizing propagation delays through the comparators and logic circuitry while maximizing bandwidth and slew rate of the error amplifier. This controller is designed for use in either current mode or voltage mode systems with the capability for input voltage feed-forward. Protection circuitry includes a current limit comparator with a 1-V threshold, a TTL compatible shutdown port, and a soft-start pin which doubles as a maximum duty cycle clamp. The logic is fully latched to provide jitter free operation and prohibit multiple pulses at an output. An under-voltage lockout section with 800 mV of hysteresis assures low start up current. During under-voltage lockout, the outputs are high impedance. BLOCK DIAGRAM Clock 4 RT 5 CT 6 Ramp 7 1.25V + OSC E/A Out 3 Error Amp NI 2 INV 1...