Current Mode PWM Controller 1.5A 16-Pin SOIC T/R

The UC1823 family of PWM control ICs 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, a TTL compatible shutdown port, and a soft start pin which will double as a maximum duty cycle clamp. The logic is fully latched to provide jitter free operation and prohibit multiple pulses at the output. An under-voltage lockout section with 800mV of hysteresis assures low start up current. During under-voltage lockout, the output is high impedance. The current limit reference (pin 11) is a DC input voltage to the current limit comparator. Consult specifications for details. These devices feature a totem pole output designed to source and sink high peak currents from capacitive loads, such as the gate of a power MOSFET. The on state is defined as a high level.

Compatible with Voltage or Current-Mode Topologies

Practical Operation @ Switching Frequencies to 1.0MHz

50ns Propagation Delay to Output

High Current Totem Pole Output (1.5A peak)

Wide Bandwidth Error Amplifier

Fully Latched Logic with Double Pulse Suppression

Pulse-by-Pulse Current Limiting

Soft Start/Max. Duty Cycle Control

Under-Voltage Lockout with Hysteresis

Low Start Up Current (1.1mA)

Trimmed Bandgap Reference (5.1V ±1%)