Current Mode PWM Controller 1.5A 16-Pin CDIP

The UC1825 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 with a 1V threshold, 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 an output. An under-voltage lockout section with 800mV of hysteresis assures low start up current. During under-voltage lockout, the outputs are high impedance. These devices feature totem pole outputs designed to source and sink high peak currents from capacitive loads, such as the gate of a power MOSFET. The on state is designed as a high level.

Compatible with Voltage or Current Mode Topologies

Practical Operation Switching Frequencies to 1MHz

50ns Propagation Delay to Output

High Current Dual Totem Pole Outputs (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)