UC3842A Current Mode Controller IC

The UC3842A designed as a high-performance fixed frequency current mode controller explicitly for off−line and DC−to−DC converter applications. It offers the designer a cost-effective method with minimal external components with which they can obtain all the performance advantages of current mode operation

These integrated circuits include a trimmed oscillator for precise duty cycle control, a temperature corrected reference, a high gain error amplifier, a current detecting comparator, and a high current totem pole output that’s excellent for power MOSFET driving. Input and reference under voltage lockouts with hysteresis, cycle by cycle current limiting, programmable output deadtime, and a latch for single pulse metering are among the extra safety features. These devices are manufactured in an 8−pin dual−in−line plastic package as well as the 14−pin plastic surface mount (SOIC−14). For the totem pole output stage, the SOIC14 package has separate power and ground pins.

The UC3842A has 16 V (on) and 10 V (off) UYLO thresholds, making it ideal for off-line converters. The UC3842 is an integrated pulse width modulator (PWM) that was created with both of these goals in mind. The UC3842 series has also been designed for efficient power sequencing of off-line converters and DC to DC regulators. In the off state, the output stage, which can drive either N Channel MOSFETs or bipolar transistor switches, is low. In addition, the UC3842A IC has a startup current of less than 0.5 mA and an oscillator discharge of 8.3 mA. In addition, for VCC > 5V, the output stage drains at least 10 mA at less than 1.2V during UVLO. The UC3842 runs at a set temperature between 0 and 70 degrees Celsius.

Applications

• Switch Mode Power Supplies (SMPS)
• DC-DC Converters
• Power Modules
•  Industrial PSU
• Battery Operated PSU